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THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
PRESENTED BY
PROF. CHARLES A. KOFOID AND
MRS. PRUDENCE W. KOFOID
CHEMISTRY
OF
ANIMAL BODIES
BY
THOMAS THOMSON, M. D.
REGIUS PROFESSOR OF CHEMISTRY IN THE UNIVERSITY OF GLASGOW,
President of the Glasgow Philosophical Society, Fellow of the Royal Societies of
London and Edinburgh, Member of the Royal Irish Academy, Fellow of the Linnean
Society, Fellow of the Geological Society, Member of the Cambridge Philosophical
Society, of the Cambrian Natural History Society, of the Imperial Medico-Chi-
rurgical and Pharmaceutic Societies of St Petersburg, of the Royal Academy of
Sciences of Naples, of the Mineralogical Society of Dresden, of the Caesarean Na-
tural History Society of Moscow, of the Literary and Philosophical and Natural
History Societies of New York, of the Natural History Society of Montreal, &c. &c.
EDINBURGH:
ADAM AND CHARLES BLACK :
LONGMAN, BROWN, GREEN, & LONGMANS, LONDON.
MDCCCXLIII.
PRINTED BY JOHN STARK, EDINBURGH.
PREFACE.
THE object of the present work is to lay before the British
public as complete a view as I can of the present state of the
Chemistry of Animal Bodies. This branch of Chemistry is much
more difficult than the chemical investigation of vegetable bodies.
The difficulty does not lie in the analysis ; for accurate and simple
methods of analyzing animal bodies as well as vegetable have
been devised ; but in separating the different animal bodies from
each other, and obtaining each in a state of purity. These pro-
cesses with respect to vegetable bodies are much facilitated by
the property which they have of crystallizing. Unfortunately
the most important animal substances, as albumen, fibrin, gelatin,
casein, &c. want that property. The consequence is, that we
have no good criterion for determining when these bodies are
pure, or what the substances are with which they are mixed.
The consequence of this difficulty has been, that the greater
number of modern chemists have confined their investigations to
those animal substances, as sugar, cholesterin, cetin, urea, &c. which
are capable of crystallizing. I am not aware of any modern
British chemist who has attempted to investigate any animal sub-
stance incapable of crystallizing. To Dr Wollaston we owe an
IV PREFACE.
interesting set of experiments on urinary and gouty calculi ; but
they were made and published before the method of analyzing
animal substances had been thought off. The same remark ap-
plies to Mr Hatchett's experiments on shells, bone, zoophytes,
and membrane. They contain many important facts which have
been overlooked by modern chemists ; but at the time of the pub-
lication of these experiments, namely, 1799 and 1800, it was
not to be expected that any attempt at ultimate analysis could
be made.
The modern chemists to whom we are indebted for the most
important analyses of animal substances, hitherto laid before the
public, are Mulder and Scherer. The results of their investiga-
tions will be seen in the following work. By laying the pre-
sent state of our knowledge before the reader, it is to be hoped
that British chemists, when aware of the vast quantity of inves-
tigations yet requisite to place Animal on the same footing as
Vegetable Chemistry, and when medical men become sensible
that the farther improvement and final perfection of physiology
will depend upon an accurate knowledge of the constituents and
properties of animal substances, the subject will speedily draw
general attention, which alone is wanting to insure a rapid
advance.
CONTENTS.
DIVISION I. OF ANIMAL PRINCIPLES, Page 2
CLASS I. ANIMAL ACIDS, ...... 2
Chap. I. Of Animal acids destitute of azote, . . 4
Sect. 1. Mesoxalic acid, ..... 4
2. Formic acid, ..... 7
3. Succinic acid, ..... 9
4. Lactic acid, ..... 9
5. Suberic acid, . . . . . 1 1
6. Sebacic acid, . . . . . 12
7. Choloidic acid, . . . . . 13
8. Cholic acid, 15
9. Pyrozoic acid, . . . . . 16
10. Pimelic acid, 18
11. Adipic acid, ..... 19
12. Lipic acid, . . . . . 21
13. Azelaic acid, 22
14. Azoleic acid, 22
15. Lithofellic acid, . . . . 22
16. Butyric acid, 26
17. Phocenic acid, 26
18. Caproic acid, ..... 26
19. Capric acid, 26
20. Hircic acid, 26
21. Ambreic acid, , 27
22. Castoric acid, 27
23. Bombycic acid, ..... 27
Chap. II. Of Animal acids containing azote, . 28
Sect. 1. Cyanogen and its compounds, . . 28
2. Uric acid, . 31
3. Pyruric acid, .....
4. Parabanic acid, . . 40
5. Oxaluric acid, . . . . 42
VI CONTENTS.
Sect. 6. Alloxanic acid, .... Page 45
7. Mycomelic acid, .... 48
8. Dialuric acid, ..... 50
9. Thionuric acid, .... 53
10. Uramilic acid, . 56
11. Hippuric acid, ..... 59
12. Choleic acid, .... 59
13. Cholesteric acid, ... 62
14. Hydromelonic acid, .... 66
15. Cerebric acid, 69
16. Oleophosphoric acid, .... 72
17. Nitroleucic acid, .... 73
CLASS II. ANIMAL BASES, . 75
Chap. I. Of Urea, . . 75
II. Of Odorin, . 83
III. Of Animin, . 87
IV. Of Alanin, 88
V. Of Ammolin, 90
VI. Of Fuscin, 91
VII. Of Crystallin, ... 92
VIII. Of Aposepedin, 93
IX. Of Taurin, 95
X. Of Chitin, ....... 97
XI. Of Ammonia, 97
CLASS III. INTERMEDIATE ANIMAL OXIDES, . . 102
Chap. I. Of Animal oxides containing azote and not oily, 102
Sect. 1. Xanthic or uric oxide, . . . 103
2. Cystin, 105
3. Allantoin, 107
4. Alloxane or erythric acid, . . . Ill
5. Alloxantin, . . . . . 115
6. Uramile, 118
7. Murexide, 119
8. Murexane, 124
Chap. II. Of Oxides not containing azote and not oily, 126
Sect. 1. Melain, 126
2. Oonin, 128
3. Diabetes sugar, . . . . 129
4. Sugar of milk, . . . . 131
Chap. III. Of Oily oxides saponifiable, . . . 134
CONTENTS. Vll
Sect. 1. Hog's lard, .... Page 134
2. Ox fat, 135
3. Goat fat, 137
4. Human fat, 137
5. Goose fat, 138
6. Duck fat, 1 39
7. Turkey fat, 139
8. Whale oil, 139
9. Oil of Delphinus Phocaena or porpoise, 140
10. Of Delphinus globiceps, . . . 140
11. Fat of Coccus cacti, or cochineal insect, 141
Chap. IV. Of Oily oxides not saponifiable, . . 145
Sect. 1. Margaron, . . , . . 146
2. Ethal, .... 147
3. Cetene, 148
4. Castorin, . . ... 148
5. Ambrein, . . . . . . 150
6. Cholesterin, . . . . 152
7. Serolin, . . . .155
8. Cantharidin, . . . • „ . 156
CLASS IV. ANIMAL COLOURING MATTERS, . . . 157
Chap. I. Of Carmin, ... 158
II. Of Sericin, ... 161
III. Of Cancrin or the colouring matter of crabs, 163
IV. Of Peristerin or the colouring matter of pigeon's
feet, ... 164
V. Of Anserin, or the colouring matter of goose foot, 165
VI. Of the colouring matter of the ancient purple dye, 166
CLASS V. ANIMAL AMIDES, . , 167
Chap. I. Of Protein, .... 168
Sect. 1. Albumen, 180
2. Albumen from silk, . . .184
3. Casein, .... 185
4. Fibrin from blood, . 192
5. Fibrin from silk, . . 198
6. Ricottin, ... 200
Chap. II. Of Gelatin, ... 201
Sect. 1. Collin, ... 201
2. Chondrin, .
3. Gelatin from silk, . . . • 217
Vlll CONTENTS.
Chap. III. Of Hematosin, . . . Page 219
IV. Of Spermatin, 226
V. Of Salivin, 228
VI. Of Pepsin, 229
VII. Of Pancreatin, 232
DIVISION II. OF THE PARTS OF ANIMALS, 232
PART I. OF THE SOLID PARTS OF ANIMALS, . , . 233
Chap. I. Of Bones, 233
II. Of Teeth, 243
III. Of Cartilage, 250
IV. Of Marrow, 253
V. Of Shells, 256
VI. Of Crusts, 260
VII. Of Zoophytes, . 262
VIII. Of Brain and Nerves, . . 265
IX. Of Muscles, 273
X. Of Tendons, . 288
XI. Of Ligaments, 289
XII. Of Cellular substance, . . . . 291
XIII. Of the Skin, 292
XIV. Of the Epidermis, .... 298
XV. Of the Rete mucosum, ... 300
XVI. Of Hair and Feathers, . . . . 301
XVII. Of Horns, Nails, and Scales, . 306
XVIII. Of Hart's Horn, .... 312
XIX. Of Serous Membranes, . . 313
XX. Of Mucous Membranes, . . 314
XXI. Of Arteries and Veins, . . . 316
XXII. Of the Mammae or Breasts, . . . 319
XXIIL Of the Pancreas, .... 320
XXIV. Of the Liver, 320
XXV. Of the Kidneys, 326
XXVI. Of the other Glands, .... 330
XXVII. Of the Lungs, 333
XXVIII. Of the Membranes of the Eye, . . 335
XXIX. Of Silk, 339
XXX. Of Spiders' Webs, ... 346
PART II. OF THE LIQUID PARTS OF ANIMALS, . . 349
Chap. I. Of Blood, 349
II. Of Saliva, 383
III. Of the Liquid of Ranula, . . .392
CONTENTS. ix
Chap. IV. Of the Gastric Juice, . . . pftge 393
V. Of the Pancreatic Juice, . . . 403
VI. Of Bile, 406
VII. Of Chyle, 413
VIII. Of Lymph, 416
IX. Of Milk, 424
X. Of the Eggs of Fowls, . . . 445
XI. Of the Roe of Fishes, . ... 455
XII. Of Urine, 459
XIII. Of Semen, . . . . . . 499
XIV. Of Synovia, 502
XV. Of Mucus, 506
XVI. Of Tears, 511
XVII. Of Liquors of the Eye, .... 512
XVIII. Of Cerumen, 516
XIX. Of Perspiration and Sweat, . . . 519
XX. Of the Liquor of the Amnios, . , . 526
XXI. Of the Liquor of Allantois, . . . 531
XXII. Of Pus, 534
XXIII. Of Animal Poisons, .... 537
XXIV. Of Feces, 542
XXV. Of the Air contained in the Swimming Bladder of
Fishes, 550
PART III. OF MORBID CONCRETIONS, . . . 552
Chap. I. Of Urinary Calculi 552
II. Of Gouty Concretions, .... 570
III. Of Salivary Concretions, . . . . 571
IV. Of Biliary Concretions, .... 574
V. Of Ossifications, . . 578
VI. Of Intestinal Concretions, . . . 580
DIVISION III.— OF THE FUNCTIONS OF ANIMALS, 585
Chap. I. Of Digestion, 586
II. Of Respiration, ..... 604
III. Of the Action of the Kidneys, . . . 643
IV. Of Perspiration, 648
V. Of Assimilation, . . . . . 651
APPENDIX, . ...... 659
1. On the mode of analyzing Organic Bodies, . 659
2. Table of Atomic Weights of Animal and Vegetable
Substances, ...... 680
b
CHEMISTRY OF ANIMAL BODIES.
THE object of this important branch of Chemistry is to give an
account of the numerous principles or definite compounds which
exist in the Animal Kingdom.
When we compare animals and vegetables together, each in
their most perfect state, nothing can be easier than to distinguish
them from each other. The plant is confined to a particular
spot, and exhibits no mark of consciousness or intelligence ; the
animal, on the contrary, can remove at pleasure from one place
to another, is possessed of consciousness, and a high degree of
intelligence. But on approaching the contiguous extremities of
the animal and vegetable kingdom, these striking differences gra-
dually disappear, the objects acquire a greater degree of resem-
blance, and at last approach each other so nearly, that it is
scarcely possible to decide whether some of those species which
are situated on the very boundary belong to the animal or vege-
table kingdom.
To draw a line of distinction, then, between animals and ve-
getables, would be a very difficult task ; but it is not necessary
at present to attempt it ; for almost the only animals whose bo-
dies have been hitherto examined with any degree of chemical
accuracy, belong to the most perfect classes, and consequently
are in no danger of being confounded with plants. Indeed, the
greater number of facts which I have to relate apply only to the
human body, and to those of a few domestic animals. The task
of analysing all animal bodies is immense, and must be the work
of ages of indefatigable industry.
ANIMAL PRINCIPLES.
The same arrangement which was followed in the Chemistry
of Vegetable Bodies may also be applied to animal bodies. We
shall first give an account of the animal principles., so far as their
nature and constitution have been determined. In the second
place, the different parts, both liquid and solid, of which the ani-
mal body is composed, will be described ; and in the third place,
we shall treat of those animal functions which are likely to be
elucidated by chemistry.
DIVISION I.
OF ANIMAL PRINCIPLES.
The substances which have hitherto been detected in the ani-
mal kingdom, and of which the different parts of animals are
supposed to be composed, may be arranged under the following
heads : —
1. Animal acids.
2. Animal bases.
3. Intermediate oxides.
4. Colouring matters.
5. Amides?
These will be described in succession under their respective
heads.
CLASS I.
OF ANIMAL ACIDS.
Several of these acids have been described in the Chemistry
of Inorganic Bodies, (Vol. ii. 45.) But so much has been done
by chemists since the year 1831, when that work was published,
that it will be necessary to resume the account of them here, re-
ferring to the former work for every thing which does not re-
quire to be corrected or amended.
The acids derived from the animal kingdom, which have been
recognized by modern chemists, and more or less accurately ex-
amined, amount to about 40. They are all compounds of two,
three, four or five different constituents. The following table
exhibits the composition of such of them as have been subjected
to analysis : —
ANIMAL ACIDS.
Atomic
weight
1. Cyanogen,
C2 Az
= 3-25
2. Mesoxalic acid,
C304
= 6-25
3. Hydrocyanic acid,
C2 Az + H
=: 3-375
4. Cyanic,
C2 Az + 0
= 4-25
5. Formic,
C2H03
= 4-625
6. Succinic,
C4 H2 O3 + HO
= 7-375
7. Lactic, .
C6 H3 O4
= 8-875
8. Butyric,
C8 H5 O3
= 9-625
9. Suberic, .
C8 H6 O3 + HO
= 10-875
10. Sebacic,
C10 H8 O3
= 11-5
11. Choloidic,
C32 H25 O6
- 33-125
12. Hydromellonic,
C6 Az4 + H
= 11-625
13. Fulminic, . 2
(C2 Az) + O2
= 8-5
14. Cyanuric, . 1^
(C2 Az) + H i* -f O3
= 8-0625
15. Cyanilic, . 3
(C2 Az) + H3 + O6
- 16-125
16. Parabanic,
C6 H2 Az2 O6
= 14-25
17. Oxaluric, .
C6 H4 Az2 O8
16-5
18. Pimelic,
C7 H5 O3 + HO
= 10-
19. Adipic,
C14 H9 O7 + 2 (HO)
= 20-875
20. Lipic, .
C5 H3 O4 + HO
= 9-25
21. Azelaic, .
C10 H8 O4 + HO
= 13-625
22. Azoleic,
C13 H13 O4
- 15-375
23. Alloxanic,
C8 H2 Az2 O8
= 17-75
24. Dialuric, .
C8 H6 Az2 O8
= 18-25
25. Mycomelic,
C8 H5 Az4 O5
= 18-625
26. Hippuric, .
C18 H8 Az O5
= 21-25
27. Theionuric,
C8 H5 Az3 O12 S2
— 27-875
28. Uramelic, .
C16 H10 Az5 O15
= 37
29. Choleic,
C41 H32 Az O12
= 48.5
30. Ch'olesteric,
C13 H10 Az* O6
= 17-875
31. Uric acid,
C8Az204-f C2H4Az202
= 21
ANIMAL ACIDS DESTITUTE OF AZOTE.
CHAPTER I.
OF ANIMAL ACIDS DESTITUTE OF AZOTE.
THESE acids are twenty-two in number. The following table
shows their names: —
1. Mesoxalic. 12. Lipic.
2. Formic. 13. Azelaic.
3. Succinic. 14. Azoleic.
4. Lactic. 15. Butyric.
5. Suberic. 16. Phocenic.
6. Sebacic 17. Caproic.
7. Choloidic. 18. Capric.
8. Cholic. 19. Hircic.
9. Pyrozoic. 20. Ambreic.
10. Pimelic. 21. Castoric.
11. Adipic. 22. Bombycic.
As nine of these acids have not hitherto been subjected to
analysis, their constitution is unknown. It is only from analo-
gy that they have been placed here.
SECTION I. OF MESOXALIC ACID.
This acid was discovered by Wohler and Liebig, and an
account of it published by them in 1838.* When a saturated
solution of alloxanate f of barytes is raised to the boiling tempe-
rature and allowed to cool, a precipitate falls, which is a mix-
ture of carbonate, alloxanate, and mesoxalate of barytes. If we
evaporate the residual liquid we obtain a crystalline crust, From
this crust alcohol separates urea,| and leaves mesoxalate of ba-
rytes.
If we let fall drop by drop a solution of alloxan§ into a boil-
ing solution of acetate of lead, a very heavy granular precipi-
tate of mesoxalate of lead falls and urea remains in solution.
* Annalen der Pharmacie, xxvi. 298.
f This acid will be described in a subsequent section. It is one of the acids
containing azote.
J An animal oxide which will be described in a subsequent part of this work.
§ Another animal oxide to be described afterwards.
MESOXALIC ACID 5
This salt of lead may be decomposed by adding the quantity of
sulphuric acid just requisite to saturate the oxide of lead. Or we
may separate the lead by passing a current of sulphuretted hy-
drogen gas through water with which the mesoxalate of lead has
been mixed. If we filter to get rid of the lead, and apply heat
to drive off what sulphuretted hydrogen may exist in the liquid,
we obtain a solution of mesoxalic acid in water.
Mesoxalic acid crystallizes readily, though the shape of the
crystals has not been determined. Its reaction is strongly acid,
and it is very soluble in water. With the salts of lime and ba-
rytes it gives precipitates, but only after the addition of ammo-
nia. It does not give oxalic acid when evaporated or boiled in
an open vessel. Its distinguishing characteristic is to form with
the salts of silver, after the addition of a little ammonia, a yellow
precipitate, which, on exposure to a gentle heat, is reduced to the
metallic state, while a great deal of carbonic acid gas is given off.
When mesoxalate of lead is heated with a little nitric acid, it
is converted into oxalate of lead, while, at the same time, nitrous
gas is given out, showing that oxygen has been added to the acid
of the salt.
When alloxanate of silver is dissolved in boiling water, it does
not change colour, but if we add a little ammonia, it becomes
yellow, and if the boiling be prolonged, it becomes all at once
black, while a lively effervescence takes place. The alloxanate
of silver in this case is decomposed into mesoxalate, to which that
kind of reaction is peculiar.
Liebig analyzed the mesoxalate of lead, and obtained
Carbon, . 6-85
Hydrogen, . 0-20
Oxygen, . 12-21
Oxide of lead, . 80-74
100-00
The quantity of hydrogen is so small, that he was of opinion
that the acid in reality contains none. In that case it is a com-
pound of carbon and oxygen only, like oxalic acid. If the oxide
of lead in the salt amount to two atoms, then the atomic weight
of the mesoxalic acid will be 6-67. For 80-74 : 19-26 : 1 28 : 6-67.
Now the numbers that accord best with the analysis and with
this atomic weight are the following :
ANIMAL ACIDS DESTITUTE OF AZOTE.
3 atoms carbon, = 2*25, or per cent 6*57
4 atoms oxygen, = 4 '00, ... 11-67
2 atoms oxide of lead, = 28.00, .., 81-76
100-00
This would make mesoxalic acid C3 O4 = 6-25, or it is equi-
valent to two atoms carbonic acid, together with an additional
atom of carbon. Admitting this composition to be correct, we
have no fewer than five acids composed of carbon and oxygen,
namely,
Croconic, . C5 O4
Mesoxalic, . C3 O4
Oxalic, . C2 O3
Rhodizonic, . C3 O5
Carbonic, . C O2
Liebig is of opinion that the want of exact accordance between the
analytical and theoretical numbers in the above analysis was owing
to the presence of a little cyanate or cyanurate of lead in the me-
soxalate subjected to analysis. This, however, can only be con-
sidered as a plausible explanation. Additional experiments are
still wanting to decide the point completely. Meanwhile, if we
admit the constituents of mesoxalic acid to be as above stated, it
is easy to explain the conversion of mesoxalate of silver by heat
into metallic silver and carbonic acid. Mesoxalate of silver must
be a compound of
1 atom mesoxalic acid, . — C3 O4
2 atoms oxide of silver, . — 2 (Ag O)
By heat the two atoms of oxygen leave the silver and combine
with the mesoxalic acid. We have consequently C3 O6 -f 2 Ag.
but C3 O6 is equivalent to three atoms of carbonic acid.
When a solution of alloxanate of barytes is boiled, it under-
goes decomposition. A white precipitate falls, which is a mix-
ture of mesoxalate, alloxanate, and carbonate of barytes. When
calcined, it gives out a notable quantity of hydrocyanic acid and
effervesces feebly with acids. When the liquid separated from
this precipitate is evaporated, it gives a yellow foliated mass of
mesoxalate of barytes, which may be purified by washing it with
alcohol. When this salt was heated with oxide of copper, it gave
no trace of azote ; 100 parts of it gave 72-1 of carbonate of ba-
FORMIC ACID. 7
rytes, equivalent to 55*91 of barytes. From this analysis, Lie-
big concludes that the salt was composed of
1 atom mesoxalic acid, . 6 '25, or per cent 37*04
1 atom barytes, . . 9'5, ... 56-30
1 atom water, . 1-125, ... 6-66
16-875 100-00
It is easy to see how mesoxalic acid results from the decompo-
sition of alloxanic acid.
Hydrous alloxanic acid is . C8 H4 Az2 O10
Subtract 1 atom urea, C2 H4 Az2 O2
Remain 2 atoms mesoxalic acid, C6 O8
SECTION II. OF FORMIC ACID.
An account of this acid has been given in the Chemistry of In-
organic Bodies, ii. 58, and the Chemistry of Vegetables, p. ] 7.
It is secreted by the Formica rufa or red ant, and is the liquid
that renders the bites of these insects so painful. It was first
publicly noticed by Mr Ray in the year 1670.* Dr Hulse had
written him that he had found this passage in Lang ham's Gar-
den of Health, " Cast the flowers of cichory ( Cichorium Intybus)
among a heap of ants, and they will soon become as red as blood."
He mentions that the fact had been observed before by various
individuals, among others by John Bohin. Dr Hulse said that
he had tried the experiment and found it to succeed. Mr Fisher
had stated to Mr Ray several years before, that, " if you stir a
heap of ants so as to rouse them, they will let fall on the instru-
ment you use a liquor which, if you presently smell to, will twinge
the nose like newly distilled oil of vitriol." Mr Fisher farther
stated, that, " when ants are distilled by themselves or with wa-
ter, they yield a spirit like spirit of vinegar, or rather like spirit
of viride aris." It dissolves lead and iron. When you put the
animals into water, you must stir them to make them angry, and
then they will spirt out their acid juice." Margraaf obtained this
acid in 1749, by distilling ants mixed with water and rectifying
the liquid, which came over. The acid obtained had a sour taste
and smell. It combined with potash and ammonia, and formed
crystallizable salts with both. It did not precipitate nitrates of
* Pail. Trans, v. 2063, or Abridgement, i. 554
8 ANIMAL ACIDS DESTITUTE OF AZOTE.
lead, silver, or mercury, nor chloride of calcium. It did not at-
tack silver, but dissolved its oxide. It did not dissolve red oxide
of mercury, but when digested with it, the mercury was reduced
to the metallic state. It did not attack copper, but dissolved its
oxide, and formed with it beautiful green crystals. It dissolved
iron filings, and yielded small crystals. This, he says, is worthy
of remark, because the solution of iron in distilled vinegar does
not crystallize. It did not attack lead, but readily dissolved red
lead, and formed beautiful crystals similar to those of acetate of
lead. It dissolved zinc, and yielded crystals quite different from
those of acetate of zinc. It scarcely acted on bismuth or anti-
mony or their oxides. It dissolved carbonate of lime with rapi-
dity, and formed with it a crystalline mass.*
In 1781, Arvidson confirmed the observations of Margraaf,
and gave ample details respecting the preparation and concentra-
tion of this acid.f In 1782, Bucholz showed how it might be
obtained in a very concentrated state by forming dry formate of
potash, mixing the dry salt with the requisite quantity of sulphu-
ric acid and distilling. He formed also a small quantity of for-
mic ether.J In 1784, Hermbstadt published an elaborate paper
on the preparation of this acid, but did not add much to what
was already known. § Richter followed in 1793, and proceeded
nearly as Bucholz had done.|| Deyeux started the notion that
formic was identical with acetic acid, and this was followed up by
a set of experiments by Fourcroy and Vauquelin, from which they
concluded that it was a mixture of acetic and malic acids. 1F This
opinion was called in question by Suerzen, who demonstrated that
pure formic acid contains no malic acid, and that its properties
were different from those of acetic acid.** This indeed had been
already proved by Margraaf; but the French chemists had paid
no attention to his experiments. Gehlen resumed the subject in
1812, and showed, in the most convincing manner, that formic
and acetic acids possess different characters, f f
Dobereiner discovered a method of preparing formic acid ar-
tificially by mixing tartaric acid and binoxide of manganese in a
* Opuscules Chymiques de M. Margraaf, i. 301.
t Wieglib's Geschichte, ii. 242. \ Ibid, ii. 269.
§ Crell's Annalen, 1784, ii. 209.
|| Ueber die neueren Gegenstande der Chemie, vi. 135.
J Phil. Mag. xv. 118. ** Gehlen's Jour. iv. 3.
•j-f Schweigger's Jour. iv. 1.
SUCCINIC ACID LACTIC ACID. 9
still, and pouring over the mixture sulphuric acid, diluted with
water. An effervescence takes place, and formic acid may be
distilled over. Wdhler and Liebig have shown that sugar, starch,
&c. may be substituted for tartaric acid. But, as the preparation
of this acid has been minutely described in the Chemistry of
Vegetable Bodies, (p. 17), the reader is referred to that work.
The characteristic property of formic acid is this : When
formic acid or formate of soda is put into a solution of any salt
of gold, platinum, or silver, an effervescence takes place, and
the gold, platinum, or silver is deposited in the metallic state. It
effervesces also, and reduces to the metallic state oxide of silver
and oxide of mercury.
This acid has been shown to consist of C2HO3 = 4.625. It
differs from oxalic acid by containing an atom of hydrogen, while
oxalic acid is C2 O3 = 4.5.
SECTION III. OF SUCCINIC ACID.
This acid has been known for nearly a century. The mode of ob-
taining it, together with its properties and constitution, has been
given in the Chemistry of Inorganic Bodies, (Vol. ii. p. 89.) A
curious discovery made by M. Bromeis during the course of the
winter 1839-40, makes it necessary to introduce it here. He
found that when nitric acid is made to act upon stearic acid,
one of the products obtained is succinic acid.* When the nitric
acid solution formed is evaporated to one-half, it concretes in
twenty-four hours to nearly a solid mass, which, when put into a
glass funnel, and washed with cold water, is freed from the mother
ley. When these washings are concentrated, they yield a white
firm crystalline salt ; which Bromeis found to be succinic acid
composed of C4 H2 O3 + HO, and agreeing in all its properties
with succinic acid from amber.
v»
SECTION IV. OF LACTIC ACID.
This acid is formed when milk becomes sour. It was first ex-
amined by Scheele, who pointed out its most remarkable proper-
ties, and noticed its analogy to acetic acid.f He called it milk
acid, which was afterwards converted into lactic acid, as more
* Annalen der Pharmacie, xxxv. 90.
t Kong. Vet. Acad. Handl. 1780, p. 116, or Scheele's Essays, p. 273.
10 ANIMAL ACIDS DESTITUTE OF AZOTE.
suitable to the English language. The French chemists endea-
voured to prove that lactic acid is merely the acetic, holding some
animal matter in solution. But this opinion was refuted by
Berzelius. It was afterwards observed that lactic acid is formed
when various vegetable substances are allowed to get sour, parti-
cularly when oatmeal is left in a considerable quantity of water.
The constitution and properties of lactic acid were fully inves-
tigated by MM. Jules Gay-Lussac and Pelouze. A full account
of the facts which they ascertained has been given in the Che-
mistry of Vegetable Bodies, (p. 22). The reader is therefore re-
ferred to that work. It has been shown by these chemists that
the atomic weight of lactic acid is 9, and that its constitution is
C6 H4 O9.
MM. Fremy and Boutron-Charlard have ascertained that
all animal substances which act as ordinary ferments have the
property of gradually converting sugar, dextrin, gums, starch,
&c. into lactic acid. The process is stopped by a heat of 212*.
Their observations have led them to the following method of
preparing lactic acid : — Put malt, slightly moistened, for a few
days into a stoppered bottle. The animal matter contained in
the malt undergoes a modification ; the temperature rises, and
if we keep this modified malt for two or three days in water of
the temperature of 104°, that water becomes strongly acid, and
contains a notable quantity of lactic acid. *
They have found that animal membranes (bladder for example)
after being dried and kept in moist air till it begins to undergo
decomposition, has the property of converting a solution of sugar
into lactic acid. When milk becomes sour lactic acid is gene-
rated by the .action of the casein on the sugar of milk. The
casein combines with lactic acid, and becomes insoluble, which
stops the process. But if we saturate the lactic acid formed with
bicarbonate of soda, the casein becomes again soluble, and act-
ing on the sugar of milk a new portion of lactic acid is formed.
This process of neutralization may be repeated till the whole
sugar of milk is converted into lactic acid, f
MM. Cap and Henry have discovered that the urea in urine
is in the state of lactate of urea. They have made some obser-
vations on the lactates which deserve to be stated J
* Jour, de Pharm. xxvi. 477. f Ibid, xxvii. 325.
j Ibid. xxv. 133.
3
SUBERIC ACID. 1 1
Lactate of zinc crystallizes in fine needles. Its taste is acid
and styptic. It is more soluble in hot than in cold water. It is
scarcely soluble in alcohol, and is precipitated in white flocks by
the alkaline sulphurets.
Lactate of lime forms small white crystals, which feel gritty
between the teeth. It has a bitterish taste. When heated it
melts and assumes the aspect of a resin. It is more soluble in
hot than in cold water. When heated with sulphuric acid there
is a slight effervescence, and the mixture becomes black, and
gives out the smell of apples.
Lactate of barytes does not crystallize, but assumes the aspect
of gum. It is very soluble in water and alcohol.
When lactic acid is treated with peroxide of lead, or deutoxide
of barytes, it is converted in a great measure into oxalic acid.
When chlorites or chlorous acid are used, the decomposition is
rapid. Oxalates are formed, which continue only for a very
short time, the effervescence showing the evolution of carbonic
acid.
Lactic acid, even when dilute, rapidly dissolves most phosphates
of lime ; oxalate of lime also is to a certain extent soluble in the
same acid.
SECTION V. OF SUBERIC ACID.
Chevreul states that when oleic, stearic, or margaric acid is
boiled with 100 times its weight of concentrated nitric acid, till
the whole oily acids disappear, we obtain on evaporation a mix-
ture of an insoluble oily acid, and another acid soluble in twenty
times its weight of water. * M. Laurent repeated the experi-
ments of Chevreul, and obtained the same acid substance. He
found it a mixture of several different acids ; but the one which
existed in greatest abundance was suberic acid •)• M. Bromeis
confirmed this curious discovery of Laurent, and analysed the
suberic acid with great care. J
If we evaporate the nitric acid solution to one-half it concretes
in twenty-four hours to a mass nearly solid. This mass is put
into a glass funnel, and washed with cold water to free it from
the mother ley. After being three times crystallized from warm
water, exposed to pressure and dried, suberic acid is obtained in
a state of purity.
* Sur les corps gras, p. 28. f Ann. de China, et de Phys. Ixvi. 157.
| Annalen der Pharm. xxxv. 89.
12 ANIMAL ACIDS DESTITUTE OF AZOTE.
Suberic acid thus obtained melts at 248 , and congeals into a
mass consisting of clear, fine, pointed needles. When heated in
a small glass flask, it generates a vapour highly impeding respi-
ration, which collects into drops and congeals into crystals, leav-
ing behind it a charry residue. The free acid precipitates ace-
tate of lead, and the precipitate is insoluble in water and in alco-
hol. Suberate of ammonia precipitates solutions of chlorides
of calcium, strontium, and barium upon the addition of alcohol.
It precipitates also the neutral salts of silver, mercury, zinc, and
tin, white. The last precipitate is readily soluble in alochol.
Sulphate of copper is precipitated bluish green, and persulphate
of iron brownish red.
Bromeis found suberate of silver composed of
Suberic acid, . . 42*1 or 10-543
Oxide of silver, . . 57-9 or 14-5
100-0
Neutral suberate of lead was composed of
Suberic acid, . . 42-38 or 10-297
Oxide of lead, . . 57-62 or 14-
100-00
Disuberate of lead
Suberic acid, » . 19-58 or 10-228
Oxide of lead, . 80-42 or 28-
100-00
Suberate of soda
Suberic acid, . . 70-62 or 9-62
Soda, . . . 29-38 or 4-
100-00
Suberate of ethyloxide
Suberic acid, . 9-75
Ether, . . . 4-625
Hydrated suberic acid being analysed with oxide of copper,
was composed of C8 H6 O3 -f HO = 10-875 ; so that the anhy-
drous acid has an atomic weight of 9-75.
SECTION VI. OF SEBACIC ACID.
Though sebacic acid is obtained during the distillation of tal-
CHOLOIDIC ACID. 13
low, and is therefore an animal product ; yet its characters are
so similar to the acids belonging to the vegetable kingdom, that
it was thought requisite to place it among them, Accordingly
it has been described in the Chemistry of Vegetable Bodies (p. 31,)
to which work the reader is referred. It has been shown by
Dumas and Peligot that the atomic weight of this acid is 11.5,
and that its components are C10 H8 O3.
SECTION VII. OF CHOLOIDIC ACID.
This acid was discovered by M. Dema^ay in the year 1838.*
The process which he employed to obtain it was the following : —
Dissolve ox bile in twelve or fifteen times its weight of water, and
boil it with an excess of muriatic acid for three or four hours,
and then let it cool. The choloidic acid will be found collected
at the bottom of the vessel in a solid mass. Decant off the liquid
portion, and melt the acid by heat three or four times successive-
ly in small quantities of distilled water. Finally, dissolve the
acid in alcohol, and agitate the solution with a little ether to dis-
solve out any cholesterin and margaric acid that it may contain.
After this treatment, if the solution be evaporated to dryness over
the water bath, there will remain choloidic acid nearly pure, but
still retaining a trace of common salt.
Choloidic acid thus obtained is a solid fatty looking substance,
of a yellow colour, destitute of smell, and having a very bitter
taste. It does not melt till heated above 212.° While solid, it
is brittle and easily reduced to powder. When heated in boil-
ing water, it melts into a brown, pasty magma. It is very
soluble in alcohol, even when weak, but little soluble in water,
and scarcely at all in ether.
The solutions of this acid strongly redden litmus-paper, and
decompose the carbonates with effervescence. The choloidates
thus formed are little soluble in water, and even in alcohol ; but
they are neutral. Acids throw it down from these compounds
in yellow flocks, which unite when heated and liquefy.
The choloidates of zinc, manganese, iron, lead, copper, and
silver are flocky precipitates, which, when cautiously heated,
become granular, and melt at about 176°. They are all slightly
soluble in water.
Demar9ay attempted to analyse the choloidates of lead, barytes,
* Ann. de Chim. et de Phys. Ixvii. 198.
14 ANIMAL ACIDS DESTITUTE OF AZOTE.
copper, and silver ; but could not succeed in obtaining these salts
constant in their composition. Water decomposes them into
super and subsalts. Hence it happens that, when we obtain the
choloidates by precipitation, the proportion of acid in them
varies with the concentration of the liquid, and when we attempt
to wash them. The consequence of this is, that the atomic weight
of this acid is still unknown.
Demar9ay made three ultimate analyses of it by means of
oxide of copper, and obtained as a means of the three,
Carbon, . 72-46
Hydrogen, . 9 '5 7
Oxygen, . 17-97
100-00
Now, it will be shown in a subsequent section that ox bile is a
compound of cJwleic acid and soda, and that choleic acid is com-
posed of C42 H36 Az O12. When bile is boiled with muriatic
acid, besides choloidic acid there is another substance formed,
which L. Gmelin, the discoverer, distinguished by the name of
taurin. This substance, which will be described in a subsequent
chapter of this volume, was analysed by Demarcay, and found
composed of C4 H7 Az O10.
Now, if from choleic acid, . C42 H36 Az O12
We subtract taurin, C4 H7 Az O10
And to the remainder, .^ C38 H29 O2
Add four atoms water, . H4 O4
We get, . . . C38 H33 O6
Now this approaches somewhat the constitution of choloidic
acid:
For 37 atoms carbon, = 27-75 or per cent. 74
30 atoms hydrogen, = 3*75 10
6 atoms oxygen, =6-00 16
37-50 100
But this formula differs too much from the analysis to be con-
fided in. And Dema^ay ascertained that the atomic weight of
choloidic acid was not 37.5. The number of atoms that would
suit the analysis would be —
CHOLIC ACID. 15
32 atoms carbon, = 24- or per cent. 72*45
25 atoms hydrogen, = 3-125 9-43
6 atoms oxygen, =6- 18 '12
33-125 100-00
But these atomic constituents differ from those of Dema^ay by
five atoms of C H.
SECTION VIII. OP CHOLIC ACID.
It has been already mentioned in the last section that bile is a
compound of choleic acid and soda. Now, when we boil bile
with a fixed alkali, the choleic acid is changed into cholic acid.
But it is not easy in this way to obtain cholic acid in any quan-
tity. The most convenient method, according to Demarcay, who
discovered this acid, is the following.*
Boil in a capsule equal parts of bile and caustic potash dis-
solved in twice its weight of water, adding just water enough to
keep the mixture liquid. This boiling process should be con-
tinued for some days. The brown clots, which separate by the
evaporation of the alkaline liquid, are removed, drained, washed
on the filter, and dissolved in water. Acetic acid precipitates
from the solution white flocks, which collect on the surface,
forming a solid crust, spongy and very friable, if most of the
choleic acid has been decomposed ; but if not, the flocks are
brown and pitchy, and require to be again treated with potash.
The precipitate is thrown on a filter, washed, dissolved in al-
cohol, and the solution left to spontaneous evaporation. White
acicular crystals gradually appear on the surface. They are
to be separated by decantation, and washed in cold alcohol. By
degrees, the liquid separates into two layers ; the undermost of
which has the colour of cashew nut, and is thick and viscid. It
is a mixture of choleic and cholic acids. The uppermost is clear
and transparent. It is a dilute solution of the two acids. This
mixture of the two acids must be again boiled with potash as
before.
The crystals must be dissolved in hot alcohol. By evapora-
tion, the acid separates in tetrahedrons. It may be rendered
pure by two or three crystallizations from alcoholic solutions.
The crystals of cholic acid are at first transparent and colour-
* Ann. de Chim. et de Phys. Ixvii. 200.
16 ANIMAL ACIDS DESTITUTE OF AZOTE.
less, but by exposure to the air they become opaque. Yet the
silky crystals deposited from boiling alcohol retain their limpi-
dity and their other characters.
The taste of cholic acid is bitter but weaker than that of bile.
It is very soluble in alcohol and ether ; but insoluble in water.
The solution reddens litmus paper, decomposes the carbonates
with effervescence, and neutralizes bases. When -the etherial so-
lution is rapidly evaporated, it leaves a deposit having a greasy
feel, showing that the acid belongs to the tribe of oily acids.
It is fixed, burning with flame, giving out smoke, and leaving
a good deal of charcoal.
The characters of the cholates are quite different from those
of the choleates and choloidates. They have not a resinous con-
sistence, do not melt in boiling water and dry easily. It is diffi-
cult to obtain them quite neutral.
The cholates of potash and soda are soluble in water, while the
cholates of lime, barytes, zinc, copper, and silver are insoluble
in that liquid. They are readily decomposed into bisalts and
disalts.
SECTION IX. OF PYROZOIC ACID.
This name was applied by Berzelius to an acid formed when ani-
mal substances are distilled per se, Unverdorben,* who first exa-
mined its properties, distinguished it by the name of brandsaure.
When an animal substance, glue, muscle, &c. is distilled
per se9 the first product is carbonate of ammonia, partly dry
and partly dissolved in a brown-coloured liquid, which con-
tains a variety of substances besides. The second product
is an empyreumatic oil ; which is generally called Dippel's oil ;
because it was Dippel who first obtained it in a state of purity.
This oil in its crude state has a yellow or rather brown colour,
and contains a variety of bases, which will be described in a sub-
sequent part of this volume. The empyreumatic oil is mixed
with potash and distilled. The pyrozoic acid remains in com-
bination with the potash. The potash residue is diluted with
water and evaporated. And this process is repeated several
times to get rid of all the empyreumatic oil which it contains.
As soon as the smell of empyreumatic oil can no longer be per-
ceived, dilute sulphuric acid is added to the alkaline liquor as
long as a matter similar to tar continues to precipitate. It is
* Poggendorf s Arinalen, viii. 262.
4
PYROZOIC ACID. 17
then distilled in a retort, and when it begins to get thick, new
portions of water are added, and the distillation is continued
till no more volatile oil passes into the receiver along with the
vapour of water. It is this volatile oil which constitutes the py-
rozoic acid.
It is a limpid liquid of a pale yellow colour, and has a sharp
and empyreumatic smell. According to Unverdorben, it is to
the presence of this acid that the empyreumatic oils owe their
peculiar odour. Its vapours redden litmus paper. It is insolu-
ble in water ; but very soluble in alcohol, ether, and the volatile
oils. In the dilute acids it does not dissolve. It ought to be
kept in well stopped phials, which should be filled with it, because
when in contact with the air, it is speedily decomposed, becom-
ing brown, and then black and thick.
It is a very feeble acid, being incapable of decomposing the al-
kaline carbonates, even when assisted by heat. Its salts crystallize
with difficulty. When exposed to the air, they gradually un-
dergo decomposition, a resin being deposited, and, if we believe
Unverdorben, a butyrate of the base remains.
Pyrozoate of potash is formed by dissolving the acid to satu-
ration in caustic potash ley. If, during the evaporation, we add
an excess of acid, we obtain at first a syrup, then minute crystals,
and finally, a dry white mass, split in all directions. This mass
bears a strong heat, without decomposition ; but it becomes at
last black, and then, according to Unverdorben, water extracts
from it butyrate of potash.
Pyrozoate of lime is soluble in fifteen times its weight of water.
When the solution is evaporated, the salt separates partly as a
pellicle and partly as a powder.
Pyrozoate of copper may be formed by double decomposition.
It is a light green powder. It is slightly soluble in water, com-
municating to that liquid a green tint. It is more soluble in al-
cohol, ether, and the fixed and volatile oils. The alkalies partly
decompose it, leaving a brown-coloured subsalt. When distilled
per se it gives off about half the acid, which it contains, unalter-
ed. It gives off also oderin, a little butyric acid, and a brownish-
coloured- substance soluble in potash.
Pyrozoic acid combines also vtifafuscin, forming a brown in-
soluble compound, from which potash extracts the acid, leaving
the fuscin.
18 ANIMAL ACIDS DESTITUTE OF AZOTE.
SECTION X. OF PIMELIC ACJD.
This acid was discovered by Laurent, and was one of the nu-
merous products obtained when oleic acid is heated with concen-
trated nitric acid.* Bromeis got it in the same way, and sub-
jected it to a rigid analysis.f
It is found most abundantly in the water employed to wash
the suberic acid, obtained from oleic acid by the process describ-
ed in a former section. It exists also in smaller quantity in the
mother ley from which the suberic acid had precipitated, and
may be obtained by slow evaporation. After being repeatedly
crystallized from water to free it from two very soluble acids,
which will be described in the two following sections, it forms a
mass, differing in appearance from suberic acid, and consisting
of single white, small grains. After having been dried in a heat
of 212° it melts at 273°, and may be easily sublimed in fine,
silky, feather-shaped crystals. It is rather more soluble in water
than suberic acid. Pimelate of ammonia does not precipitate
chlorides of barium, strontium, calcium, manganese, and zinc, nor
sulphate of copper.
It has no smell but a much stronger acid taste than suberic
acid has. It is not altered by exposure to the air. It is very
soluble in boiling water. At 64-|° one part of it is soluble in
35 of water. Alcohol, ether, and sulphuric acid dissolve it rea-
dily when assisted by heat.
It was analyzed with nearly the same result by Laurent and by
Bromeis. The last mentioned chemist found pimelate of silver
composed of
Pimelic acid, . 37-75 or 87-37
Oxide of silver, 62-25 or 14-5
100-00
When analyzed by means of oxide of copper, the hydrous acid
gave Laurent
Carbon, . 52-52
Hydrogen, . 7-50
Oxygen, . 39-98
100-00
\
* Ann* de Chim. et de Phys. Ixvi. 163. f Annalen der Pharm. xxxv. 104.
ADIPIC ACID. 19
Bromeis obtained
Carbon, . 49-56
Hydrogen, . 7 -06
Oxygen, . 43-38
100-00
And the analysis of the pimelate of silver gave him
Carbon, . 21-98
Hydrogen, . 2-64
Oxygen, . 13-13
Oxide of silver, 62-25
100.
From these analyses the following formula may be deduced,
C7 H5 O3 + HO = 10. For
7 atoms carbon 5*25 or per cent 52-5
6 atoms hydrogen = 0*75 7.5
4 atoms oxygen = 4*00 40-0
10-00 100-
SECTION XI. OF ADIPIC ACID.
This acid, like the preceding, was discovered by Laurent*
The mother water from which the pimelic acid had been obtain-
ed was freed as much as possible from nitric acid by evapora-
tion, taking care not to evaporate too far, otherwise the whole
mass is decomposed violently and becomes black. We must
therefore, after a cautious evaporation, let the solution crystal-
lize for two or three days. Draw off the liquid portion by a
sucker, and wash the crystals with a little cold water. These
evaporations and crystallizations must be repeated till the liquid
ceases to deposit any more crystals. The crystals are dissolved
in water and again crystallized. They constitute a mixture of
adipic and lipic acids. To separate them, the crystals are dried
and then dissolved in ether by the assistance of heat The solu-
tion is left to spontaneous evaporation till it is reduced to one-
half. The portion remaining liquid is decanted off the crystals
deposited and evaporated. The two products thus obtained from
* Ann. de China, et de Phys. Ixvi. 166.
20 ANIMAL ACIDS DESTITUTE OF AZOTE.
the ether are dissolved separately in boiling alcohol, and the so-
lutions are left to spontaneous evaporation. These solutions and
crystallizations are repeated two or three times. Two sets of
crystals are obtained. The one in groups of round tubercles is
the adipic acid ; the other in elongated plates is the lipic acid.
Adipic acid thus obtained is in tubercles composed of needles
radiating from a centre. Laurent always obtained it of a brown
colour, which enabled him to distinguish it from pimelic acid,
which is white. The spherules of which it is composed are softer
and longer than those of pimelic acid. After being dried at 212°,
it melts when heated to 293°, and, like pimelic acid, it may be
readily sublimed in beautiful crystals. It is almost equally so-
luble in ether, water, and nitric acid.
Adipate of ammonia crystallizes in needles. It does not pre-
cipitate chlorides of barium, strontium, and calcium; nor sulphates
of magnesia, manganese, nickel, cobalt, and copper ; nor ace-
tate of lead. It precipitates perchloride of iron brick-red. When
nitrate of silver is dropt into adipate of ammonia, no precipitate
appears at first ; but when a sufficient quantity of nitrate has
been added, a white precipitate falls.
M. Bromeis analyzed adipate of silver, and found it compos-
ed of
Adipic acid, . 39-39 or 18-846
Oxide of silver, 60-61 or 29.
100-00
The adipate of barytes was composed of
Adipic acid, . 48-58 or 17-95
Barytes, . . 51-42 or 19.
100-00
Bromeis found the constitution of the hydrous acid to be
Carbon, . 49-56
Hydrogen, . 7.06
Oxygen, . 43-38
100-
The analysis of adipate of silver agreed with this ; only that
there were two atoms of water in the acid. They had been dis-
placed by the oxide of silver. Now, the formula that accords
LIPIC ACID.
best with this analysis, and with the atomic weight of the anhy-
drous acid, as it exists in adipate of silver, is C14 H9 O7 +
2 (HO) = 20-875.
14 atoms carbon, = 10-5 or per cent. 50-30
1 1 atoms hydrogen, = 1-375 ... 6-58
9 atoms oxygen, = 9-0 ... 43-12
20-875 100-
+
SECTION XII. — OF LIPIC ACID.
This acid is contained in the thick brown mother ley separated
from pimelic acid, as mentioned in the 10th section of this chap-
ter. When this liquid is farther evaporated, and left for some
time at rest, the lipic acid separates in large transparent crystals
as mentioned in the last section.
The crystals are oblique elongated plates, usually grouped
together. This acid is much more soluble in cold water than
either of the two preceding acids. It dissolves readily in alco-
hol and ether. When heated in a retort, it may be distilled over
without alteration. When slowly heated, it sublimes in long
needles. When the temperature is raised cautiously, it gives out
water, and an anhydrous acid remains which melts between
284° and 293°. Its vapour excites coughing, and is very suffo-
cating.
Lipate of ammonia crystallizes in long prisms. When mixed
with a solution of chloride of barium, nothing happens at first ;
but in a few minutes crystals of lipate of barytes are deposited.
They are square prisms passing into octahedrons. In twenty-four
hours hardly any lipate of barytes remains in solution.
Chloride of calcium behaves nearly as chloride of barium.
Chloride of strontium gives a kind of coronet.
When the dry lipates are heated with sulphuric acid, lipic
acid is disengaged in needles.
Lipate of ammonia does not precipitate the salts of manganese
nor of magnesia. It precipitates the salts of iron, copper, and
silver. According to the analysis of Laurent, to whom we are in-
debted for everything known of this acid, its constitution may
be represented by this formula, C5 H3 O4 + HO = 9-25.
ANIMAL ACIDS DESTITUTE OF AZOTE.
SECTION XIII. OF AZELAIC ACID.
This acid, like the three preceding, was discovered by Lau-
rent ; but he procured it only in small quantity, and probably
not pure. It was obtained, like the preceding, from the liquid
formed by digesting oleic acid in nitric acid. The suberic acid,
obtained by the method described in a former section, was agi-
tated with ether, which dissolved the azelaic acid. The ether was
evaporated, and the residue left in contact with cold ether, and
this ether was again evaporated. This process was repeated.
What remained was azoleic acid. It constituted an opaque mass,
in which small radiated spheres may with difficulty be distinguish-
ed.
Azelate of ammonia does not precipitate chlorides of barium,
strontium, and magnesium, not even though alcohol be poured
into the mixture. Concentrated chloride of calcium gives a pre-
cipitate ; but if that salt be dilute, no precipitation takes place.
The salts of lead, silver, and mercury are precipitated white.
According to the analysis of Laurent, the constitution of this
acid is represented by this formula, C10 H8 O4 + H O = 13-625.*
SECTION XIV. OF AZOLEIC ACID.
This acid was also discovered by Laurent, and is one of the
products of the action of nitric acid on oleic acid. It was ob-
tained from the oil swimming on the surface of the nitric acid,
which amounted to about a fifth of the oil originally employed.
This oil was converted into an ether by mixing it with alcohol
and sulphuric acid, and distilling off a certain portion. If we
distil the whole, the ether is decomposed. The ether was de-
composed by an alcoholic solution of potash. The potash being
now neutralized by muriatic acid, the azoleic acid separated. It
is liquid and insoluble in water. Laurent analyzed it, (suppos-
ing it to contain four atoms oxygen,) and gives the following for-
mula for its constitution : C13 H13 O4 - 15-375. f
This acid has been but very imperfectly examined. M. Bro-
meis has promised us a set of experiments on it and the azelaic
acid.
SECTION XV.- — OF LJTHOFELLIC ACID.
This acid was discovered by M. GoebelJ of Dorpat, in a sup-
* Laurent, Ann. de China, et de Phys. Ixvi. 172. f
Ann. der Pharra. xxxix. 237.
LITHOFELLIC ACtD. 23
posed gall-stone in the zoological cabinet of that place, labelled,
a gall-stone consisting of concentric layers. There was no ac-
count of its origin or history. It was oval, had a nucleus of al-
bumen coloured by bile, weighed 240 grains, and had a specific
gravity of 1*043 at the temperature of 68°. It was insoluble in
water, muriatic acid, and acetic acid ; slightly soluble in ether,
and readily soluble in boiling alcohol, with the exception of a
little albumen coloured greenish-brown by bile. From this so-
lution it crystallized in hard pulverizable crystals, which Wohler
found to be short six-sided prisms.
When heated in a platinum spoon it melted into a yellow li-
quid, which caught fire when the heat was raised, leaving a small
quantity of shining charcoal, which gradually burnt away without
leaving any residue.
When heated with nitric acid it frothed strongly and the acid
was partly decomposed, then it dissolved in the surplus acid.
The solution being evaporated left a beautiful lemon-yellow mass
insoluble in water ; but when rubbed or heated in that liquid it
assumed the appearance of a white resin.
When heated with potash ley it is saponified, giving out the
smell of ambergris. From this soap acids throw down a yellow-
ish white powder, identical with the crystals from the alcoholic
solutions, and constituting a new acid, to which Goebel has given
the name of lithofellic acid.
To obtain this acid the concretion was dissolved in boiling al-
cohol of 99 per cent, and the greenish brown filtered liquid slow-
ly evaporated. The acid was deposited in crystals coloured
greenish yellow by bile. They were pulverized and washed with
cold alcohol to remove the colouring matter, and again dissolved
in boiling alcohol and crystallized. They were now nearly co-
lourless. The crystals were oblique prisms with oblique termi-
nations.
At 68° it dissolves in 29*4 times its weight of alcohol, and in
six and a-half times its bulk of boiling alcohol ; 44*4 parts of
ether were required at 68°, and 47 parts of boiling ether to
dissolve one of the acid.
The melting point of the crystallized acid is 401°. At that
temperature, if allowed to cool, it becomes solid, assumes a crys-
talline appearance, and becomes opaque. But if the temperature be
24 ANIMAL ACIDS DESTITUTE OF AZOTE.
raised a few degrees above 401°, it assumes on cooling the form
of a transparent vitreous, brittle matter, which becomes electric
when rubbed. In this state it fuses at 221°. It is not the least
crystalline, but when a little alcohol is poured on it many cracks
appear, which have a certain regularity, and even under a thin
layer of alcohol it is speedily converted into a mass of crystals.
When heated in a retort a white vapour was given out, which
condensed into a yellowish liquid, and there passed over into the
receiver a mixture of empyreumatic oil and acid water. The oil
had a penetrating smell similar to that of oil of amber. A small
quantity of charcoal remained in the retort. The product of
distillation seemed to contain a new acid. It formed with potash
a soap, which, when decomposed by muriatic acid, was analogous
to the empyreumatic oil employed.
When heated with a solution of potash or soda, and when the
solution is concentrated, it is almost immediately converted into
a soap. The soap separates from the liquid when sufficiently
concentrated, and swims on the surface as long as the heat con-
tinues ; on cooling it constitutes a hard mass, like white colo-
phon. This soap is soluble in ether, alcohol, and water, and is
decomposed by acids.
Twenty-eight grains of pure lithofellic acid being saponified
by soda, and the soap decomposed by muriatic acid, left 24-375
grains of white dry lithofellic acid. The chloride of sodium
weighed 4-875 grains. This quantity corresponds with 2-553 of
soda. Hence the soap is composed of
Lithofellic acid, 24-375 or 38-19
Soda, . . 2-553 or 4
Lithofellic acid dissolves in liquid ammonia, and is again preci-
pitated unaltered in the state of a white powder by muriatic
acid. If we heat the solution on the water-bath decomposition
takes place, the lithofellic acid being precipitated in plates. The
soda soap of this acid gives heavy and insoluble precipitates with
salts of silver, mercury, iron, lead, platinum, lime, and barytes.
By the action of nitric acid on lithofellic acid a new acid is
formed, which has a lemon-yellow colour, dissolves in soda ley,
and separates as a soap from the concentrated ley. Muriatic acid
throws down a brown mass insoluble in water, which on cooling
becomes solid.
This acid was subjected to an ultimate analysis by burning it
3
LITHOFELLIC ACID. 25
with oxide of copper by MM. Ettling and Will. 573*5 parts of
it gave 1480-5 of carbonic acid and 558-5 of water. Hence tbe
constituents are
Carbon, . 70-41
Hydrogen, . 10-82
Oxygen, . 18-77
100*
From an analysis of lithofellate of silver they have been induced
to represent its constitution by the formula C42 H38 O8 = 44.25.
If we calculate from this formula we get
42 carbon = 31'5 or per cent 71-19
38 hydrogen = 4'75 . 10-73
8 oxygen — 8 . 18-08
44-25 100-00
Were we to adopt the atomic weight of 38*125 derived from
Groebel's analysis of the soda soap, we might consider lithofellic
acid as composed of C36 H33 O7 = 38-125— a formula which
approaches the numbers obtained by the analysis of Ettling and
Will pretty nearly. Wdhler gives the formula C40 H36 O8 =
42*5, which agrees very closely with his analysis. He obtained
Carbon, . 70-83
Hydrogen, . 10-60
Oxygen, . 18-57
lOOf
The lithofellate of lead was composed of
Acid,. . . 68 or 44.6
Oxide of lead, . 32 or 21 or 1J atom
100
This would make the atomic weight of the acid 44-6. The sil-
ver salt, according to Wohler's analysis, is composed of
Lithofellic acid, . 75 or 43-5
Oxide of silver, . 25 or 14-5
100
* Ann. der Pharm. xxxix. 244. f Ibid. xli. 154.
^O ANIMAL ACIDS DESTITUTE OF AZOTE.
Wdhler considers the formula C40 H36 O8 = 42-5 as most pro-
bable, because the acid has all the characters of a resin.
SECTION XVI. OF BUTYRIC ACID.
The existence of this acid was announced by Chevreul in
1814 ; but it was not till the year 1818 that he got it in a state
of purity. As the name indicates, it is obtained from butter.
It has been described in detail in the Chemistry of Inorganic
Bodies, (ii. 132,) and we have no additional information to state.
To that work, then, we refer the reader.
The constitution of butyric acid, according to the analysis of
Chevreul, is C8 H5 O3 = 9-625.
SECTION XVII. OF PHOCENIC ACID.
This acid was extracted from the oil of the porpoise, (Delphi-
nus globiceps,) by Chevreul in 1817. There is nothing to add
to the account given of it in the Chemistry of Inorganic Bodies,
(ii. 130.)
According to the analysis of Chevreul, the constitution of this
acid is C10 H7* O3 = 11-4375. It is exceedingly probable from
this analysis, that phocenic acid is identical with the sebacic.
SECTION XVIII. OF CAPROIC ACID.
Discovered by Chevreul in 1818 in the butter of the cow and
goat. It has been described in the Chemistry of Inorganic Bo-
dies, (ii. 134.)
According to Chevreul's analysis, it is composed of C12 H10
O3 = 13-25.
i
SECTION XIX. OF CAPRIC ACID.
Discovered by Chevreul in 1818 in the butter of the cow and
goat. It has been described in the Chemistry of Inorganic Bo-
dies, (ii. 136.)
Its constituents are C18 H14 O3 - 18*25.
SECTION XX. OF HIRCIC ACID.
The few facts ascertained by Chevreul respecting this acid have
been stated in the Chemistry of Inorganic Bodies, (ii. 137.)
It has not hitherto been analyzed.
AMBREIC, CASTORTC, AND BOMBYCIC ACIDS. 27
SECTION XXI. OF AMBREIC ACID.
Described in the Chemistry of Inorganic Bodies, (ii. 141.)
SECTION XXII. OF CASTORIC ACID.
This acid was obtained by Brandes* from casforin, a substance
extracted from castor, which is secreted in two bags in the ingui-
nal regions of the beaver.
When castorin is treated with nitric acid till it is completely
decomposed, and the residual liquid concentrated, small yellow
prisms and grains are deposited, which constitute castoric acid.
It reddens litmus-paper ; it is soluble in water, and the solu-
tion is yellow ; it forms with ammonia a supersalt, which crys-
tallizes in small grains. This salt, when neutral, does not pre-
cipitate the salts, having the alkaline earths for bases. But it
throws down the salts of protoxide of iron white ; the salts of cop-
per light-green ; the salts of lead and the nitrate of silver white ;
and these last precipitates do not alter their colour by exposure
to the air.
SECTION XXIII. OF BOMBYCIC ACID.
It was observed by Chaussier in 1783, that silk-worms have
the property of reddening litmus-paper. Hence he inferred that
they contained a peculiar acid.f It appears, from Chaussier's
statement, thatBoissier de Sauvage had already noticed this acid ;
but neither of them gave any account of its properties, or seem
to have attempted to procure it in a separate state.
In 1836, M. Mulder mixed together 100 grammes of raw yel-
low silk and 50 grammes of sulphuric acid previously diluted
with 5 litres of water in a retort, and distilled cautiously that the
heat might not be sufficiently high to injure the silk.J The li-
quid which came over was acid, and had a strong and peculiar
smell. To free it from any sulphuric acid which it might have
contained, an excess of bary tes water was added, and the sulphate
of bary tes being separated, the uncombined barytes which it might
still cpntain was thrown down by a current of carbonic acid gas.
The liquid was then evaporated to dryness, and a saline crust
was obtained, which was bombycic acid. When a little sulphu-
* Br. Arch. xvi. 281.
t Nouv. Mem. de Dijon, 1783, p. 70 ; or Ci ell's Annalen, 178*, i. 576.
J Poggendorfs Annalen, xxxvii. 611.
28 ANIMAL ACIDS CONTAINING AZOTE.
ric acid was mixed with this crust, a sharp and penetrating smell
was perceived, and a white vapour exhaled, which acted as an
acid. From this experiment it follows, that silk contains an acid
which is separated from it by sulphuric acid ; that this acid is vo-
latile, has a strong smell, and forms a soluble salt with barytes.
Bombycic acid is not found in the fibres of silk, but in its ge-
latin and albumen. It may be obtained by boiling the raw silk
in water, and evaporating the liquid.
When mixed with a great deal of water, it has a peculiarly
strong fatty smell, is very volatile ; has a sharp taste, and reacts
weakly as an acid. When exposed to the light, it is decompos-
ed ; the peculiar smell vanishes, and a crop of mucors make their
appearance.
It forms soluble salts with lime, barytes, potash, soda, and am-
monia, and is separated from these bases by the strong acids, as
becomes evident by the smell. Its solution in water is not pre-
cipitated by salts of iron, mercury, copper, and silver, showing
that its combinations with the bases of these salts are soluble.
Concentrated acids mixed with dilute aqueous solutions of
bombycic acid do not act upon it, if we except muriatic acid,
which occasions a smell similar to that of iodine.
It is obvious, from the characters of this acid, thus determined
by Mulder, that it is neither cyanic acid, as Liebig conjectured,
nor benzole acid, as was the opinion of Proust.
CHAPTER II.
ANIMAL ACIDS CONTAINING AZOTE.
THESE acids are all, or at least the greater number of them,
feeble. They amount at present to about eighteen species ; but
they will probably be greatly augmented as the examination of
animal substances proceeds.
SECTION I. OF CYANOGEN AND ITS COMPOUNDS.
These have been treated of at great length in the Chemistry
of Inorganic Bodies, (Vol. ii. p. 208,) and- in the Chemistry of
Vegetable Bodies, (p. 207.) But the compounds of this very pro-
lific substance are so numerous, that it may not be improper to
give a list of the principal of them in this place.
CYANOGEN AND ITS COMPOUNDS. 29
Cyanogen, C2 Az - 3.25
1. Chloride of cyanogen, C2 Az + Chi. = 775.*
2. Bromide of cyanogen, C2 Az + Br. = 13-25. f
3. Iodide of cyanogen, C2 Az + lod. — 194
4. Sulpho-cyanogen, C2 Az + S2 = 7-75.
1. Cyanic acid, C2 Az O + Aq = 5-375.§
2. Fulminic acid, 2(C2 Az O) = 4-25. ||
3. Cyanuric acid, 3(C2 Az O) + 3 HO - 7-625.1F
1. Cyanate of ammonia, C2 Az O -f Az H3 + HO = 6*5.
Urea, C2 Az O + Az H3 + HO = 6-5.
2. Cyanate of potash, C2 Az O -f- KO = 11-375. And so of
the other cyanates.
1. Fulminate of mercury, 2 (C2 Az O) + 2 (Hg O) = 35-5.
2. Fulminate of silver, 2 (C2 Az O) + 2 (Ag O) = 37-5.
3. Fulminate of copper, 2 (C2 Az O) + 2 (Cu O) = 14-25.
4. Fulminate of Zinc, 2 (C2 Az O) + 2 (Zn O - 14-5. And
so of the other fulminates.
1. Crystallized cyanuric acid, 3 (C2 Az O) + 3 (HO) +
4 Aq = 15.5.
2. Cyanurate of ammonia, 3 (C2 Az O) + Az H3 + HO
= 10-875.
3. Cyanurate of potash, 3 (C2 Az O) + 2 (HO) + KO =
15-875.
or 3(C2 Az O) + HO + 2(KO)=20.75
or 3 (C2 Az O) + 3 (KO) = 35.625.
4. Cyanurate of silver, 3 (C2 Az O) + 2 (Ag O) + HO -
37-75.
or 3 (C2 Az O) + 3 (Ag O) = 51-125.
1. Hydrocyanic acid or prussic acid, C2 Az H = 3-375.**
2. Hydrocyanate of ammonia, C2 Az H + Az H3 = 5.5. And
so of the other hydrocyanates.
1. Cyanet of potassium, C2 Az + K = 8-25.
2. Cyanet of sodium, C2 Az + Na = 6-25
3. Cyanet of zinc, . C2 Az + Zn = 7-375.
4. Cyanet of iron, . C2 Az -f Fe = 6-75.
* See Inorganic Chemistry, ii. 234. f Ibid. ii. 238.
t Ibid. ii. 239. § Ibid. ii. 225. || Ibid. ii. 229.
^ Ibid. ii. 227 ; and Vegetable Chemistry, p. '208.
*» Chemistry of Inorganic Bodies, ii. 219.
30
ANIMAL ACIDS CONTAINING AZOTE
5. Cyanet of mercury, C2 Az -4- Hg — 15-75.
6. Cyanet of silver, C2 Az -f Ag = 1675.
7. Cyanet of palladium, C2 Az -f Pa = 10-
8. Cyanet of gold, C2 Az -f 2 (Au) = 28-25. And so
of the other cyanets.
1. Ferrocyanogen, 3 (C2 Az) + Fe = 13-25.
Symbol for ferrocyanogen Cfy.
2. Ferro-cyanhydric acid Cfy + H2 = 13.5.
Ferro-prussic or Ferro-chyazic acid of Porret.
3. Ferrocyanet of potassium, Cfy -f 2 K ±= 23.28.
Prussiate of potash. But it contains also three atoms water.
r *} F i
4. Ferrocyanet of potassium and iron, 2 Cfy -f < ^ V = 35.
5. Prussian blue, 3 Cfy -f^Fe2 — 43.25.
6. Basic prussian blue, 3 Cfy -f 1 2J^f |-f FeO1* — 54*75.
7. Soluble prussian blue, 2 Cfy -f | ^ j — 38-5.
8. Ferrocyanet of zinc and potassium, 2 Cfy + 1 3^n | -41-875
9. Ferrocyanet of ammonium, Cfy + 2 (Az H4) -f- 3Aq =
17-625.
10. Ferrocyanet of sodium, Cfy -f 2 N -f- 12 Aq = 32-75. And
so of the other ferrocyanets.
11. Ferocyanet of potassium and calcium, Cfy + «j p , >=20-75.
12. Ferrocyanet of potassium andiron, 2 Cfy -f < «^ >=42
This is the greenish white precipitate which falls when a solu-
tion of protoxide of iron is mixed with prussiate of potash.
13. Basic cyanodide of iron, 3 Cfy + ||Q?| } = 58-25
The preceding salt washed and then dissolved in water :
1. Ferricyanogen, 2 Cfy = 26-5.
The supposed basis of Gm elm's red prussiate of potash :
2. Ferricyanhydric acid, 2 Cfy + 3 H = 26-875.
3. Ferricyanet of potassium, 2 Cfy -f- 3 K = 41-5.
Gmelin's red prussiate of potash :
4. Ferricyanet of iron, 1 atom ferricyanogen, — 26-5.
3 atoms iron, — 10-5.
37-
URIC ACID. 31
This is the blue precipitate thrown down from a solution of
protoxide of iron by the red prussiate.
1. Sulphocyanogen, C2 Az + S2 = 7*75.
2. Sulphocyanhydricacid, (C2 Az + S2) + H = 7-875.
3. Sulphocyanet of ammonium, (C2 Az + S2) + Az H4 = 10.
4. Sulphocyanet of potassium, (C2 Az H- S2) K = 12-75.
5. Sulphocyanet of lead, (C2 Az + S2) + Pb = 20-75.
6. Basic sulphocyanet of lead, (C2 Az -f- S2) + Pb + PbO -
34-75.
7. Sulphocyanet of mercury, (C2 Az -f S2) + Hg = 20-25.
SECTION II. OF URIC ACID.
This very important substance was discovered, and its charac-
ters ascertained by Scheele, in 1776.f He found it in urinary
calculi ; and all the calculi examined by him consisted of it.
From the properties of it pointed out by Scheele, it was consi-
dered as an acid, and Morveau gave it the name of lit hie acid. {
The experiments of Scheele were confirmed by those of Berg-
man,§ and of Fourcroy and Vauquelin during their examination
of urinary calculi. || In 1798, a long paper on urinary calculi
by Dr Pearson was inserted in the Philosophical Transactions.^!
It contained little that had not been already determined by
Scheele. But Pearson affirmed that the characters of the lithic
acid of Scheele were not those of an acid. He called it an oxide,
and the term lithic being in his opinion improper, he distinguished
it by the name of uric oxide ; a term which he had already em-
ployed in his translation of the French Chemical Nomenclature.**
Fourcroy, admitting the impropriety of the name lithic, but still
maintaining that the substance was an acid, gave it the name of
uric acid, which was generally adopted. ff
Brugnatelli made some experiments on this acid, one of which
* Inorganic Chemistry, ii. 241.
f Kougl. Vet. Acad. Handbl. 1.776, p. 327 ; or Scheele's Chemical Essays,
p. 199.
\ EneycL Meth. Chemic Art. Acides ; or Lavoisier's Traite de Cbimie,
p. 318.
§ Kong. -Vet. Acad. Handl. 1776, p. 333.
|| Ann. de Chim. xvi. 63, and xxvii. 225.
f Phil. Trans. 1798, p. 15.
** See the last table in that work. ft Ann. de Chim. xxvii. 286.
ANIMAL ACIDS CONTAINING AZOTE.
was rather important. He showed that when it was treated with
nitric acid, a considerable quantity of oxalic acid was formed.*
This throws some light upon the existence of oxalate of lime in
urinary calculi ; for Scheele had shown that uric acid is a con-
stant ingredient in urine.
Gay-Lussac first attempted to analyse uric acid by means of
black oxide of copper. He measured the volumes of carbonic
acid and azotic gases evolved, and found them to each other as
69 : 31, or as 5 : 2-246.f This, as we shall see afterwards, con-
stitutes a tolerably near approximation to the truth. The pro-
perties of uric acid were farther investigated by Dr Henry, who
made it the subject of his thesis, when he took his medical degree
at Edinburgh in 1807. His experiments were revised and pub-
lished in an English dress in 18134 Berard subjected it to
analysis, and published the result in his thesis on the analysis of
animal substances, which he supported at Montpellier, when he
graduated in that University in 1817.§ In the same year an im-
portant paper by Dr Prout, on the nature and proximate princi-
ples of urine, was published in the eighth volume of the Medico-
Chirurgical Transactions. He gives an analysis of uric acid, re-
markable for the care and accuracy with which it was conducted.
Uric acid was again analyzed by Kodweiss in 1830,|| by Mitscher-
lich,1f and by Liebig** in 1834.
Scheele had observed that when uric acid is distilled, an acid
substance sublimed, which he considered as analogous to succinic
acid. Dr Pearson obtained it also, and considered it as benzoic
acid. It was examined more in detail by Dr Henry, who con-
cluded from his experiments that it was a new acid united to
ammonia. The subject was taken up by Chevallier and Las-
saigne in 1820. ft These gentlemen examined its properties in
detail, showed its peculiar characters, subjected it to analysis,
and distinguished it by the name of pyruric acid.
In the year 1838, a most important set of experiments on uric
acid, and the various new compounds which it is capable of yield-
* Ann. de Chim. xxviii. 56. f Ibid. xcvi. 53.
\ Memoirs of the Literary and Philosophical Society of Manchester, (2d Se -
ries), Vol. ii.
§ Ann. de Chim. et de Phys. v. 292. || Poggendorf's Armalen, xix. 1.
^f Ibid, xxxiii. 335. ** Annalen der Pharmacie, x. 47.
ff Ann. de Chim. et de Phys. xiii. 158.
URIC ACID. SS
ing, was published by Wohler and Liebig,* These chemists have
thrown a new light upon the nature of uric acid, and on the im-
portant part which it acts in the animal economy. If the view
which they have taken prove correct, — and it agrees better with
the phenomena than the old opinion, — the statement of Dr Pear-
son, that uric acid is not entitled to be considered as a real acid,
will after all be the true one. Liebig and Wohler consider it
as a salt having urea for its base. The other, or acid constituent,
has never been obtained in a separate state, and perhaps is inca-
pable of existing except when united to a base.
Uric acid exists in small quantity in human urine, and may
be obtained in crystals when that liquid is cautiously concentra-
ted. Many urinary calculi consist almost entirely of it. In
them, however, it is mixed with the colouring matter of urine,
with the mucus of the bladder, and with other substances. The
urine of birds, as was first shown by Dr "Wollaston, consists
chiefly of urate of ammonia. The excrements of serpents (void-
ed about once a month) consist almost entirely of the same sub-
stance.
The easiest method of obtaining uric acid is to take the ex-
crements of serpents or of birds, which are solid, nearly white,
and consist of urate of ammonia, mixed with more or less of
animal matter. Dissolve this matter by means of heat in a ley
of caustic potash or soda, and evaporate the solution to a thick
magma. Spread this magma upon a fine cloth, and wash it cau-
tiously with hot water till the liquid passes off colourless ; then
subject it to strong pressure between folds of blotting-paper.
Dissolve it in boiling water, and precipitate the uric acid by
means of muriatic acid. Collect it on a filter, and wash it with
cold water till that liquid ceases to have any taste.
Thus obtained, uric acid has a snow-white colour, and is usu-
ally in fine powder, though sometimes in very minute prismatic
crystals. It has been obtained in pretty large crystals by Bott-
ger. They were hydrated uric acid composed of one atom uric
acid, and four atoms water, f
It is destitute of taste and smell. According to Dr Henry, it
dissolves, in about 1400 times its weight of boiling water, and the
* Annalen der Pharmacie, xxvi. 241 ; or Ann, de Chim. et de Pbys. Ixviii.
225.
f Ann. der Pharm. xxxii. 315.
C
< ANIMAL ACIDS CONTAINING AZOTE.
solution reddens litmus-paper. Dr Pearson states it to be inso-
luble in cold water, and with his statement my trials agree. It
certainly requires more than 10,000 times its weight of cold
water to dissolve it. Muriatic acid does not dissolve it, nor sul-
phuric acid, but it dissolves with effervescence in nitric acid
when assisted by heat, and if the solution be cautiously evapo-
rated to dryness, the residue gradually assumes a beautiful pink
colour. Water dissolves this residue, and assumes the same pink
colour, but it gradually fades and disappears. The alkaline car-
bonates do not dissolve uric acid, but it dissolves readily in caus-
tic potash or soda ley, and also in ammonia, though less readily.
The alkaline solutions are promoted by heat. It decomposes soap
when assisted by heat, as it does also the alkaline sulphurets.
Lime-water also dissolves uric acid, as was first shown by Scheele.
It is insoluble in alcohol and ether.
M. Lipowitz* has made some experiments on the solubility of
uric acid, which deserve to be stated. One part of carbonate or
bicarbonate of potash or soda, dissolved in 90 parts water,
dissolves two of uric acid. The mixture must be boiled. During
the boiling, the carbonic acid is expelled and an alkaline urate
formed. On cooling, the urate is ^deposited in warty crystals,
which require much water to dissolve them. The affinity of uric
acid for bases is augmented by heat. When uric acid is boiled
with a solution of acetate of potash, the acetic acid is disengaged
and urate of soda formed. On cooling, the acetic acid again
displaces the uric. When one part of borax is dissolved in nine-
ty parts water, the solution dissolves little more than one part
of uric acid, but the solution does not require heat. A gelati-
nous biurate of soda separates. When this salt is burnt, it leaves
carbonate of soda. When we add boracic acid so as to form
2 atoms biborate of soda -f 1 atom uric acid, and heat, we get
2 atoms urate of soda -f- 1 atom quaterborate of uric acid.
On cooling, we have 1 atom biurate of soda -f- 1 atom biborate
of soda -f 1 atom biborate of uric acid.
When phosphate of soda is dissolved in water and the solution
boiled with uric acid, urate of soda is formed, which is deposited
on cooling, and the liquid becomes acid.
Carbonate of lithia requires 200 times its weight of water to
dissolve it. If it be suspended in water, mixed with uric acid,
* Ann. der Pharm. xxxviii. 348.
URIC ACID. 35
and heated, a solution immediately takes place : 1 part of lithia,
and 1 of uric acid, dissolve in 90 parts water, at the temperature
of 122°, and they remain in solution when the liquid is cooled.
At the boiling point, 1 part of lithia, and almost 4 parts of uric
acid dissolve in 90 parts of water, with the evolution of much car-
bonic acid. On cooling, the whole concretes into a gelatinous
mass, easily redissolved by heat. Urate of lithia at 122° is so-
luble in sixty times its weight of water. Caustic lithia dissolves
about six times its weight of uric acid. Urate of lithia is com-
posed of
Uric acid, 85-54 or 10-35 or 1 atom.
Lithia, . 14-46 or 1*75 or 2 atoms.
100-00
M. Lipowitz proposes lithia as an excellent reagent for sepa-
rating uric acid from the other ingredients in calculi. We have
only to heat the powdered calculus with a solution of lithia ;
filter and add muriatic acid ; pure uric acid falls down. He
boiled lepidolite in fine powder with uric acid. On dropping
muriatic acid into the filtered liquid, uric acid precipitated. The
same experiment succeeded with spodumen, containing lithia.
When dry uric acid is heated in chlorine gas, cyanic acid,
muriatic acid, and chloride of cyanogen are formed. When moist
uric acid is subjected to the same treatment, the substances form-
ed are carbonic acid, ammonia, and oxalic acid. When it is long
boiled in caustic potash ley ammonia is given out, and oxalic
acid formed.
According to Braconnot it combines with the alkalies in two
proportions, forming with each, urates and diurates. The diurate
of potash, according to his analysis is composed of
Uric acid, . 66-4 or 23-1
Potash, 33-6 or 12-
100-
According to this analysis its atomic weight is 23.
When the alkaline urates are heated to redness in the open
air, the residue is a mixture of charcoal and carbonate of the al-
kali. But when the experiment is conducted in close vessels,
cyanodide of the alkali, cyanate and carbonate are formed, as
appears from the experiments of Lipowitz.*
* Ann. der Pharm. xxxviii. 356.
36
ANIMAL ACIDS CONTAINING AZOTE.
The following table exhibits the result of the different ultimate
analyses of uric acid :
Berard.
Prout.
Kodweiss.
Mitcherlich.
Liebig.
Carbon,
33-62
39-875
39-79
35-82
37-15
Hydrogen,
7-06
2-225
2-00
2-38
2-49
Azote,
39-23
31-125
37-40
34-60
34-66
Oxygen, .
20-09
26-775
20-81
27-20
25-70
100-00 100- 100- 100- 100-
If we leave out Berard's analysis, because his hydrogen differs
so much from all the others, the mean of these analyses gives,
Carbon, . 38-16
Hydrogen, .- 2-27
Azote, . 34.45
Oxygen, . 25-12
100-00
Now the number of atoms which agrees best with this mean,
and which approaches the atomic weight determined by Bracon-
not, is the following :
10 atoms carbon, . 7-5 or per cent. 35*72
4 atoms hydrogen, 0-5 ... 2-38
4 atoms azote, . 7-0 ... 33-33
6 atoms oxygen, . 6-0 ... 28-57
21-0 100-00
The carbon does not agree with the above mean, but it almost
coincides with the result of Mitcherlich's analysis. The quantity
of oxygen is above the mean ; the number of atoms of oxygen
deduced from that mean should only be 5£ instead of 6.
I am disposed, in consequence of these discrepancies, to adopt
the analysis of Dr Prout as the most exact. It leads to the fol-
lowing atomic constitution :
11 atoms carbon, — 8-25 or per cent 37-94
4 atoms hydrogen, = 0'5 ... 2-30
4 atoms azote, = 7-0 ... 32-18
6 atoms oxygen, = 6-0 ... 27-58
21-75 100-00
Wbhler and Liebig have adopted the formula, C10 H4 Az4 Oc,
URIC ACID. 37
but C11 H4 Az4 O6 would have answered their purpose as well.
They consider uric acid to be a compound of 1 atom urea and
1 atom of a peculiar acid represented by the formula, C8 Az2 O4 ;
but we may as well suppose it C9 Az2 O4, and then we have
1 atom urea, . C2 H4 Az2 O2
1 atom peculiar acid, . C9 Az2 O4
Making ] atom of uric acid, C11 H4 Az4 O6 = 21-75
When uric acid is subjected to distillation in a retort, it fur-
nishes a considerable quantity of cyanuric acid and urea.
From the] late experiments of Liebig, it would appear that
the atomic weight of cyanuric acid ought to be doubled. If so,
it consists of 3 (C2 Az) Az3 O6 = 16-125. This being the atomic
weight of the acid, it is clear that the salt formerly called bicy-
anurate of potash is, in fact, a cyanurate, and when heated to
212°, the cyanuric acid loses an atom of water ; for the salt is
composed of
1 atom, 3 (C2 Az) + H2 O5, . 15
1 atom potash, . . .6
21
He analyzed the salt formerly called cyanurate of potash, (but
which will be a dicyanurate if we double the atomic weight of
the acid), and found it had lost another atom of water, the acid
now consisting of (C2 Az)3 HO4.
He analyzed cyanurate of silver, and found it a compound of
three atoms oxide of silver, with a new modification of cyanuric
acid. For it is deprived of an additional atom of water, and con-
sisted of (C2 Az)3 O3 = 12-75.*
Thus it appears that cyanuric acid exists in three states.
When uncombined it is . (C2 Az)3 H3 O6 = 16-125
When united to 1 atom potash, . (C2 Az)3 H2 O5 = 15.
United to 2 atoms potash, . (C2 Az)3 H O4 = 13-875
United to 3 atoms oxide of silver, (C2 Az)3 O3 = 12-75
An additional atom of base always displacing a corresponding
atom of water.
Now, neither urea nor cyanuric acid, in any of these four
states, is volatile ; yet they are obtained from uric acid by sub'
limation. But the cyanuric acid may be a product from the de-
* Ann. cle Chim. et de Phys. lxviii.18.
38 ANIMAL ACIDS CONTAINING AZOTE.
composition of urea, if we admit with Wohler and Liebig, that
urea is one of the constituents of uric acid.
SECTION III. OF PYRURIC ACID.
It has been stated in the last section, that when Scheele sub-
jected uric acid to distillation, a substance sublimed which he
took for succinic acid ; that Dr Pearson considered it to be ben-
zoic acid ; that Dr Henry examined it more in detail, and was
of opinion that it constituted a new and peculiar acid; and, finally,
that Chevallier and Lassaigne subjected it to a rigorous examina-
tion, and gave it the name of pyruric acid.
It may be obtained either by heating uric acid, or uric acid
calculi in a retort : the calculi must be pulverized and washed
with boiling water before being put intt) the retort. The acid
sublimes in plates, which attach themselves to the upper part of
the retort. Besides this there is a good deal of acid, combined
with ammonia, dissolved in the water which comes over into the
receiver. There comes over at the same time cyanuric acid, and,
in general, carbonate of ammonia, and an empyreumatic oil.
The acid may be obtained from the matter which has passed
into the receiver, and which speedily assumes a solid form. This
matter is to be treated with boiling water, and filtered. The
filtered liquor lets fall a brown bituminous-looking substance-
When saturated with ammonia and evaporated, small crystals
are formed, consisting of super-pyrurate of ammonia, but disco-
loured by an empyreumatic oil. Being, dissolved in water, and
the solution mixed with diacetate of lead, a precipitate falls,
which, being washed with water, and decomposed by sulphuret-
ted hydrogen gas, filtered and evaporated, yields crystals of pyruric
acid. The colour is still yellow, but they may be purified by re-
peated solutions and crystallizations.
Pyruric acid is white. It crystallizes in small needles. When
heated it melts and sublimes entirely in white needles. When
passed through a red-hot glass-tube it is decomposed into char-
coal, oil, carburetted hydrogen, and carbonate of ammonia. It
dissolves in about forty times its weight of cold water. The so-
lution reddens vegetable blues. It dissolves in boiling alcohol
(of 0*843) and when the solution cools is deposited in small white
grains.
It dissolves in concentrated nitric acid. When the solu-
PYRURIC ACID. 39
tion is evaporated to dryness we obtain the pyruric acid unal
tered.
Lime forms with pyruric acid a salt which crystallizes irregu-
larly, and which has a bitter and slightly acrid taste. When ex-
posed to a gentle heat this salt melts, and on cooling assumes the
appearance of yellow wax. When calcined in a platinum crucible
it left 8 -6 of lime. Hence Chevallier and Lassaigne concluded
that it was a compound of
Pyruric acid, . 9 1 -4 or 3 7 * 1
Lime, . . 8-6 or 3-5
100-0
When barytes is united to this acid a white pulverulent salt is
obtained little soluble in cold water. With potash and ammonia
it forms soluble and crystallizable salts. The pyrurate of soda
is soluble, but it does not crystallize. The acids when dropt into
a solution of these salts precipitate the pyruric acid in the form
of a wh ite powder. Of all the metallic salts tried, only the salts of
peroxide of iron, black oxide of copper, oxide of silver, oxide of
mercury, and the trisacetate of lead are precipitated by the py-
rurate of potash.
The pyrurate of peroxide of iron has a chamois-leather colour,
that of copper is light-blue, and those of silver, mercury, and lead
white. The salt of lead formed by mixing solutions of pyrurate
of soda and trisacetate of lead is composed, according to Che-
vallier and Lassaigne, of
Pyruric acid, . 28-5 or 16*6
Oxide of lead, . 71-5 or 48 or 3 atoms.
100O
If we suppose the pyrurate of lime analyzed to be a bisalt and
this a tris-salt, the atomic weight of pyruric acid will be 17*5. It
was analyzed by Chevallier and Lassaigne, who obtained
Carbon, . . 28-29
Hydrogen, . . 10-00
Azote, . . 16*84
Oxygen, . . 44-32
99-45
There is no likelihood that these numbers are exact. The
smallest number of atoms that would agree with this analysis is,
ANIMAL ACIDS CONTAINING AZOTE.
4 Atoms carbon, = 3 or per cent. 27 '9
8 atoms hydrogen =1 ... 9*3
1 atom azote, =1-75 ... 16-3
5 atoms oxygen. =5 ... 46*5
10-75 100
But 10-75 does not at all agree with the atomic weight of py-
ruric acid, as deduced from the analysis of the two pyrurates
above stated, namely, 17 '5.*
SECTION IV. OF PARABANIC ACID.
This acid was discovered by Wcihler and Liebig in 1838.f
They prepared it in the following way : Uric acid was dissolv-
ed by means of heat in eight times its weight of moderately
strong nitric acid, and after all evolution of gas had ceased, the
solution was evaporated. At a certain point of concentration,
it deposits colourless, lamellar crystals, Sometimes the whole
liquid concretes into these crystals, and sometimes they do not
appear till after an interval of some time. These crystals con-
stitute the parabanic acid of Wb'hler and Liebig. They may
be purified by a second crystallization.
The crystals are six-sided prisms, colourless and transparent,
they have a strong acid taste, similar to that of oxalic acid. But
parabanic acid is more soluble in water than oxalic. The crys-
tals do not effloresce though exposed to the heat of 212°. They
preserve their shape and transparency, but assume a red colour.
When exposed to a stronger heat they melt ; one portion is su-
blimed while another is decomposed with the disengagement of
hydrocyanic acid.
When the cold solution of parabanic acid is mixed with ni-
trate of silver, a white pulverulent precipitate falls, which is very
much increased by the cautious addition of ammonia. The last
formed portion of this precipitate is gelatinous.
When this acid is decomposed by oxide of copper the volume
of azotic gas evolved is to that of the carbonic acid gas as 1 : 3.
Hence it follows that the atoms of azote and carbon in the acid
are to each other as 1 : 3.
Wohler and Liebig analysed parabanate of silver in order to
ascertain the atomic weight of the acid. This salt is insoluble
in hot water; but, like most of the salts of silver, it dissolves in
* Ann. de Chim. et de Phys. xiii. 155. f Ibid. Ixviii. 273.
PARABANIC ACID. 41
liquid ammonia and in nitric acid. 100 parts of the salt prepar-
ed without ammonia yielded 70-6 parts of oxide of silver. Hence
it was composed of,
Parabanic acid, 2 9 '4 or 12-06
Oxide of silver, 70-6 or 29 = 2 atoms.
100-0
100 parts of the same salt, which had been thrown down by
ammonia, contained 70*11 of oxide of silver, and, therefore, was
composed of,
Parabanic acid, . 29-89 or 12-34
Oxide of silver, . 71-11 or 29= 2 atoms.
100-00
The mean atomic weight of parabanic acid deduced from these
two analyses, (supposing the salt to contain two atoms of oxide of
silver,) is 12-2.
The crystals of parabanic acid were analyzed three times suc-
cessively in Liebig's laboratory. The mean result of these an-
alyses give the composition as follows :
Carbon, . 31-66
Hydrogen, . 1-95
Azote, . 24-62
Oxygen, . 41-77
100-00
We have just seen that the atoms of azote are to those of car-
bon as 1 : 3. But if we were to calculate the number of atoms
on the supposition that 24*62 represented only 1 atom of azote,
we would obtain 7*125 for the atomic weight. While from the
analysis of parabanate of silver we know that the atomic weight
is above 12. It is clear from this that the acid must contain 2
atoms of azote. Hence its constitution must be,
Six atoms carbon = 4*5, or per cent, 31-58
Two atoms hydrogen = 0-25 . 1-75
Two atoms azote = 3-5 . 24-56
- Six atoms oxygen =6-0 . 42-11
14-25 100-
This would make the atomic weight of parabanic acid 14-25.
But the atomic weight deduced from the parabanate of silver is
12-2. The difference amounts to 2-05, or very nearly two atoms
ANIMAL ACIDS CONTAINING AZOTE.
of water. It would appear from this, that when parabanic acid
is united with oxide of silver it parts with two atoms of water,
which are replaced by two atoms oxide. Hence the acid united
with the oxide of silver contains no hydrogen, but is composed
of C6 Az2 O4 = 12.
No other parabanate but that of silver is known. Whenever
the acid is placed in contact with a soluble base it is converted,
under the influence of the most gentle heat, into oxaluric acid.
When heated with other acids it undergoes no alteration. Nor
is it altered when its aqueous solution is boiled.
SECTION V. OF OXALURIC ACID.
This acid also was discovered by Wb'hler and Liebig in
1838,* during their important examination of uric acid and its
compounds.
Parabanic acid, the preparation of which was given in the
preceding section, is very soluble in caustic ammonia, and the
solution is perfectly neutral. If it be raised to the boiling point,
and then left to itself, it concretes on cooling into a white mag-
ma composed of small needles. This substance is oxalurate of
ammonia. If, to a hot concentrated solution of this salt in wa-
ter, we add sulphuric or muriatic acid, and cool the mixture as
quickly as possible, oxaluric acid falls in a white crystalline
powder. It may be purified by^ washing it in cold water, as it
is but little soluble in that liquid.
Its solution has a decidedly acid taste, reddens litmus paper,
and neutralizes the bases. The neutral oxalurates, when dis-
solved in water, precipitate nitrate of silver in white flocks, which
dissolve in boiling water, and crystallize on cooling in long silky
needles.
Neither" oxaluric acid nor oxalurate of ammonia throw down
any precipitate when dropped into dilute solutions of salts of
lime. But, if we add an excess of ammonia, a white gelatinous
precipitate falls, soluble in a great deal of water.
If we boil free oxaluric acid in water till no crystals are de-
posited on cooling, the acid is completely decomposed. The so-
lution is very acid. When concentrated, it first deposits crys-
tals of oxalate of urea and then pure oxalic acid.
When oxaluric acid is decomposed by oxide of copper, the
volumes of azotic gas and carbonic acid gas obtained are to each
other as 1 '. 3, as is the case with parabanic acid.
* Ann. de Chim. et de Phys. Ixviii. 276.
OXALURIC ACID. 43
The mean of two analyses in Liebig's laboratory gave the con-
stituents of oxaluric acid as follows :
Carbon, 27-06 or 6 atoms = 4*5 or per cent. 27-27
Hydrogen, 3-07 or 4 atoms = 0-5 . 3-03
Azote, 21-05 or 2 atoms = 3 -5 . 21-21
Oxygen, 48-82 or 8 atoms = 8-0 . 48-49
100- 16-5 100-
Its atomic weight is 16*5. It is easy to see how, by boiling, it
is decomposed into urea and oxalic acid.
Oxaluric acid is C6 H4 Az2 O8
2 atoms oxalic acid are C4 O6
1 atom urea . C2 H4 Az2 O2
Making together . C6 H4 Az4 O8
which is obviously an atom of oxaluric acid.
When crystallized oxaluric acid unites to oxide of silver, it
parts with an atom of water, which is replaced by an atom of
oxide of silver. This is obvious from the composition of oxalu-
rate of silver. The mean of three analyses give
Oxaluric acid, . 51-28 or 15-26
Oxide of silver, . 48-72 or 14-5 = one atom.
100-
The atomic weight of the acid united to the oxide of silver is
15-26, while that of the crystals is 16-5 ; the difference, 1-24, is
very nearly an atom of water. Hence the acid, when in com-
bination with oxide of silver, is C6 H3 Az2 O7= 15-375. This
constitution was confirmed by an analysis of oxalurate of silver
by means of oxide of copper.
Oxalurate of ammonia crystallizes in silky needles. It is
very soluble in hot, but little soluble in cold water. When
heated to 212° it loses no weight. The mean of two analyses by
means of oxide of copper gave,
Carbon, 24-07 or 6 atoms = 4-5 or per cent. 24-16
Hydrogen, 4-85 or 7 atoms = 0-875 . 4-70
Azote, 28-08 or 3 atoms = 5 -25 . 28-19
Oxygen, 43-00 or 8 atoms = 8-00 . 42-95
18-625 100-00
ANIMAL ACIDS CONTAINING AZOTE.
This is obviously 1 atom acid, . C6 H4 Az2 O8
1 atom ammonia, . H3 Az
C6 H7 Az3 O8
When solutions of oxalurate of ammonia and chloride of cal-
cium are mixed, brilliant and transparent crystals of oxalurate
of lime are gradually deposited. With excess of lime another
precipitate is obtained in a granular and yet gelatinous form.
This last compound may be prepared by supersaturating oxalu-
ric acid with lime, or by pouring some ammonia on crystallized
oxalurate of lime. It is soluble in a great quantity of water,
and very soluble in dilute acids, even in acetic acid.
Oxaluric acid is obviously a combination of two atoms oxalic
acid with one of urea.
Two atoms oxalic acid, . C4 O6
One atom urea, . C2 H4 Az2 O2
Constituting an atom of oxaluric acid, C6 H4 Az2 O8
It deserves attention that the oxalate of urea possesses also
acid characters.
One atom of uric acid + 4 atoms oxygen may be resolved
into 1 atom urea, 2 atoms carbonic acid, and 1 atom anhydrous
parabanic acid, provided we adopt the constitution of uric acid
given by Liebig.
1 atomuricacid C10H4Az4 O6 1 f l atom u!"eaj . , 9* H" Az" £*
4 atoms oxveen O4 f = 1 2 carbomc acid C °
tl parabanic acid C6 Az2O4
C10H4Az4 O10 C10 H4 Az4O10
Alloxane, heated with an excess of nitric acid, combines with
two atoms of oxygen, and may be resolved into carbonic acid,
parabanic acid, and water.
1 atomalloxane C8H4Az2Ow 1 f Satomscarb. acid C2 O4
2 do. oxygen O2 /=: V Pa^banic acid C6 AzK*
1-4 water . H4 O4
C8H4Az2O12 C8H4Az2O12
ALLOXANIC ACID. 45
SECTION VI. OF ALLOXANIC ACID.
This acid was discovered by Wohler and Liebig in 1838.*
They prepared it in the following way :
Barytes water was added to a hot solution of alloxane.\ A
precipitate fell, which was soluble by a gentle heat. On
continuing to add barytes water, a point was reached at which
the whole liquor became muddy, and being left to itself, a ba-
rytes salt was deposited, crystallized in white heavy plates. This
salt assumed a red colour when the solution happened to contain
a little alloxantin. The liquid which covered these crystals was
an aqueous solution of the same salt, and contained nothing else.
This salt was alloxanate of barytes.
We obtain the same precipitate, though not quite so pure,
when we add chloride of barium to a solution of alloxane, and
then pour in a little ammonia. The salt in that case is deposit-
ed under the form of a thick gelatinous magma, which is com-
pletely dissolved by the addition of a great deal of water, or by
a dilute acid, however weak.
A similar salt is formed when alloxane is treated in the same
way with strontian or lime water, or by chloride of strontium, or
of calcium and ammonia. The strontian salt scarcely differs
in appearance from that of barytes. The salt of lime presents it-
self in the form of grains or short transparent prisms. All these
salts contain water of crystallization, which they lose when
heated to 248°. Alloxane does not precipitate nitrate of silver ;
but, if we add ammonia to the mixture, a white precipitate falls,
which becomes yellow by boiling.
Alloxanate of barytes is easily decomposed by sulphuric acid,
and the alloxanic acid obtained from it in a state of purity.
Alloxanic acid possesses considerable power. It decom-
poses the carbonates and acetates with facility. When eva-
porated to the consistence of a syrup, it crystallizes in a few
days into a hard radiated mass, which does not absorb moisture
from the atmosphere. When combined with barytes it forms a
salt precisely similar to that from which it was obtained. With
ammonia it forms a crystallizable salt. Oxide of silver dissolves
in it, and when the solution is dried it resembles gum in appear-
* Ann. de Chim. et de Phys. Ixviii. 284.
•}• This substance, which is obtained by treating uric acid with strong nitric
acid, will be described in a subsequent chapter of this volume.
46 ANIMAL ACIDS CONTAINING AZOTE.
ance. Alloxanate of ammonia precipitates the salts of silver
white. The free acid dissolves zinc with the disengagement of
hydrogen gas. Sulphuretted hydrogen has no action on it.
Alloxanate of silver was analysed in Liebig's laboratory. It
was formed by mixing together solutions of alloxane, ammo-
nia, and nitrate of silver. It became gray when dried, and was
found composed of,
Alloxanic acid, . 38-53 or 18-17
Oxide of silver, . 61-47 or 29 = 2 atoms.
100-
The atomic weight by this analysis is 18-17.
When the salt was decomposed by oxide of copper, the azotic
gas and carbonic acid gas evolved were to each other as 1 : 4.
The mean of two analyses in Liebig's laboratory gave,
Carbon, . 12-91 or 8 atoms — 6-0 or per cent. 12-84
Hydrogen, . 0-68 or 2 atoms — 0-25 . 0.54
Azote, . 7-53 or 2 atoms = 3-5 . 7-48
Oxygen, . 17-41 or 8 atoms = 8-0 . 17-11
Oxide of silver, 61-47 or 2 atoms = 29.0 . 62.03
100-00 46-75 100.00
This makes the constitution of the acid C8 H2 Az2 O8 = 17-75.
Doubtless the crystallized acid contained two atoms of water,
which were replaced in the salt by two atoms of oxide of silver.
Hence the constituents of the crystals must have been C8 H4
Az2 O10 = 20.
Alloxanate of silver deflagrates at a temperature much be-
low redness. The residue gives out a considerable quantity of
cyanic acid.
Alloxanate of Barytes. — This salt, prepared in the way de-
scribed in the beginning of this section, constitutes short trans-
parent prisms or a precipitate in brilliant crystalline plates. It
loses water when heated to 212°. The crystals then become
opaque and milky-white. When decomposed by oxide of copper
the volumes of azotic and carbonic acid gases evolved are to each
other as 1 : 3. When heated to 248° it loses 20 per cent of water.
100 parts of the salt were found to contain 49-35 of barytes.
This was the mean of two analyses, the first yielding 49*25, the
second, 49-46 per cent.
ALLOXANIC ACID. 4?
When decomposed by oxide of copper the volume of azotic
gas was to that of carbonic acid gas as 1 : 3.
The mean of two analyses, the first by oxide of copper, the se-
cond by chromate of lead, gave the following constituents of the
salt:
Carbon, 14-20 or 8 atoms = 6 or per cent. 15.84
Hydrogen, 1-17 or 3 atoms = 0-375 . 0.99
Azote, 9-21 or 2 atoms — 3-5 . 9-24
Oxygen, 26-07 or 9 atoms = 9-0 . 23-76
Barytes, 49-35 or 2 atoms = 19.0 . 50-17
37-875 100.
According to this analysis the atomic weight of alloxanic acid
is 18-875. But it was afterwards found, that when the salt was
heated to 302° it lost 2 per cent of water, which is nearly equi-
valent to one atom. Hence the atomic weight of the acid is
17-75, and its constitution C8 H2 Az2 O8, and alloxanate of bary-
tes is,
1 atom alloxanic acid, . 17*75
2 atoms barytes, . 19*
36-75
Alloxanate of Strontian. — This salt may be prepared in the
same way as alloxanate of barytes. It is in the form of small
acicular transparent crystals, containing water of crystallization.
When decomposed, the volumes of azotic and carbonic acid gases
obtained are to each other as 1 : 3. At 248° it loses 22-5 per
cent of water. 100 parts of the crystals left when ignited, 45-16
of carbonate of strontian, equivalent to 31-73 of strontian.
Hence the constituents of the salt are,
Alloxanic acid, 45*77 or 1 atom = 17-75 or per cent. 44 '66
Strontian, . 31-73 or 2 atoms = 13.00 32-70
Water, . 22'50 or 8 atoms = 9-00 . 22-64
39-75 100.
Alloxanate of Lime. — When we add chloride of calcium to a
solution of alloxane, no precipitate falls until ammonia be ad-
ded, which occasions the separation of a thick gelatinous depo-
site, very soluble in acetic acid, and becoming crystalline when
48 ANIMAL ACIDS CONTAINING AZOTE.
left to itself. It was analyzed by Wohler and Liebig, and found
composed of,
1 atom alloxanic acid, (C8H2 Az2 O8) 17-75
2 atoms lime, . . 7-00
2 atoms water, . . 2-25
27.
Now alloxane is C8 H2 Az2 O8 + 2 (HO). Hence it would ap-
pear, that when alloxane combines with a base, it divides itself
into one atom of alloxanic acid, and 2 atoms of water.
SECTION Vn. OF MYCOMELIC ACID.
When a gentle heat is applied to a mixture of ammonia and
alloxane, it becomes yellow, and when cooled and concentrated
it concretes into a yellow jelly. This jelly is a combination of
ammonia and anew acid, which Wohler and Liebig, who discover-
ed it, have distinguished by the name of mycomelic acid*
If we employ concentrated solutions of alloxane and ammo-
nia, there generally separates, as soon as we apply heat, a heavy
yellow powder, which is the same combination. When the li-
quid assumes a red colour alloxantin is present.
Mycomelate of ammonia dissolved in hot water and treated
with an excess of dilute sulphuric acid, gives a transparent gela-
tinous precipitate of mycomelic acid, which when washed and
dried assumes the form of a yellow porous powder. We obtain
the same acid directly if we supersaturate a hot mixture of
alloxane and ammonia with dilute sulphuric acid, and boil the
mixture for a few minutes.
Mycomelic acid is very little soluble in cold water, but rather
more soluble in hot water. It reddens vegetable blues and dis-
solves in ammonia and the fixed alkalies, but does not form with
them crystallizable salts. Mycomelate of silver is yellow and
flocky. It may be obtained by mixing together solutions of my-
comelate of ammonia and nitrate of silver. The mixture may
be boiled without in the least altering the nature of the salt.
Mycomelic acid, after being dried in the temperature of 248°,
was decomposed by means of oxide of copper. The volume of
azotic gas evolved was to that of the carbonic acid gas as 1 : 2.
The constituents of the acid were found to be,
• Ann. de Chim. et de Phys. Ixviii. 295.
OF ALLOXANIC ACID. 1<)
Carbon, 31-06 or 8 atoms — 6 or per cent. 32-21
Hydrogen, 3.57 or 5 atoms = 0-625 . 3-35
Azote, 36-24 or 4 atoms = 7-0 . 37.59
Oxygen, 29-13 or 5 atoms = 5-0 . 26-85
100-00 18-625 100-
The difference between the experimental and calculated re-
sults in this case are rather too great. This difference Wohler
and Liebig ascribe to the presence of a little uramile* in the salt,
which is a product of the decomposition of alloxantin by am-
monia.
It is easy to explain the formation of mycomelic acid. One
atom of alloxane and two of ammonia are decomposed into one
atom of mycomelic acid and five atoms of water.
1 atom alloxane, C8H6Az2O10 "J /"I atom mycomelic
2 atoms ammo- i i ac^' ~ C8 H5 Az4 O5
nia, H6Az2 ) V 5 atoms water, H5 0s
C8H10Az4010 C8H10Az4010
Dry mycomelic acid possesses exactly the same composition
as allantoin when united to oxide of silver.
Wohler and Liebig attempted to determine the atomic weight
of this acid by analyzing mycomelate of silver, but they did not
consider the results which they obtained as deserving of confi-
dence ; because the yellow gelatinous precipitate obtained by
mixing nitrate of silver with mycomelate of ammonia changes
its colour even when washed in the dark, It becomes brown, and
•when dried on the water-bath assumes the form of a hard green
mass, giving an olive coloured powder, not completely soluble in
ammonia. They obtained from this salt by combustion 44.39
per cent of silver, equivalent to 47*68 of oxide of silver. This
would make the salt,
Mycomelic acid, 52-32 or 15-91
Oxide of silver, 47-68 or 14-5 = 1 atom.
100-
According 'to this analysis the atomic weight of mycomelic acid
is 15-91. The difference between this weight and that of the
liydrous acid is 2*715, which is more than two atoms of water,
* This substance will be described in a subsequent chapter of this work,
D
50 ANIMAL ACIDS CONTAINING AZOTE.
Were we to admit in the hydrous acid two atoms of water, its
constitution would be C8 H3 Az4 O3 -f 2 (HO), and its atomic
weight in the anhydrous state would be 16*375. But analogy
would lead to the inference that the hydrous acid contains only
one atom of water, and that its atomic weight is 17*5.
When mycomelate of silver is heated by itself, it gives out a
great deal of cyanate of ammonia, which, when dissolved in wa-
ter and evaporated, becomes urea. There is formed besides a
crystalline substance, having a peculiar smell, and coloured red
by another matter.
SECTION VIII. OF DIALURIC ACID.
We owe the discovery of this acid also to Wohler and Liebig.*
When a current of sulphuretted hydrogen gas is passed through
a solution of alloxane, this last substance is converted into allox-
antin. If we continue the current of sulphuretted hydrogen
through the boiling solution after all the alloxane is converted
into alloxantin, there is a new deposit of sulphur, and the liquid
becomes decidedly acid. If, after all the alloxantin is decom-
posed, we saturate the liquor with carbonate of ammonia, a great
quantity of white crystalline matter falls, consisting of dialuric
acid united to ammonia.
We may obtain the same salt in abundance by dissolving uric
acid in dilute nitric acid, and mixing the liquid with sulphohy-
drate of ammonia, taking care that there is left in the liquid a
slightly acid reaction. The precipitate (which contains sulphur)
is to be washed, dissolved in boiling water, and treated with car-
bonate of ammonia. On cooling the liquid concretes into a
white crystalline mass.
If we reduce alloxane by means of zinc and muriatic acid, and
after separating the crystals formed, we treat the residue with
carbonate of ammonia till the oxide of zinc, at first precipitated,
is again redissolved ; the same salt is deposited, provided the mix-
ture be left for some time in a state of repose.
This white precipitate becomes red when dried at the common
temperature. At 212° it becomes blood red without losing am-
monia. It is very soluble in boiling water, but is mostly depo-
sited again when the solution cools, especially if we add carbonate
of ammonia to the liquid.
* Ann. de Chim. et de Phys. Ixviii. 263.
DIALURIC ACID. 51
Its solution precipitates salts of barytes, white ; salts of lead
in yellow flocks. The precipitate becomes violet when exposed
to the air. The salts of silver are immediately reduced by it.
When decomposed by oxide of copper the volume of azotic
gas evolved is to that of the carbonic acid gas as 3 : 8. The
mean of three analyses made in Liebig's laboratory by means of
oxide of copper gave
Carbon, 31-27 or 8 atoms — 6 or per cent 29*82
Hydrogen, 4-49 or 7 atoms = 0-875 ... 4-34
Azote, 27-36 or 3 atoms = 5-25 ... 26-09
Oxygen, 36-88 or 8 atoms =. 8-00 ... 39'75
100 20-125 100*
If from C8 H7 Az3 O8 we subtract H3 Az, or an atom of am-
monia, the remainder C8 H4 Az2 O8 must give us the constitu-
tion of dialuric acid. Its atomic weight is 18. We may con-
sider it as alloxane minus 2 atoms of oxygen, or alloxantin minus
1 atom oxygen and 1 atom water.
Dialurate of ammonia dissolves in potash with the disengage-
ment of ammonia. The acids throw down nothing from the so-
lution.
The attempts of Wohler and Liebig to obtain dialuric acid in
an isolated state were unsuccessful. When separated from its
base it is decomposed with great facility into a great number of
products which have not yet been accurately examined.
* There is obviously a mistake in the numbers given in Liebig's paper, (An-
nalen der Pharmacie, xxvi. 277.) The data given,
1st. 0-5095 grammes of dialurate of ammonia gave 0-215 water, and 0-542
carbonic acid.
2rf. 0-430 of the salt gave 0-163 water and 0-5635 carbonic acid.
3d. 0 377 gave 0- 455 water and 0-404 carbonic acid.
0-455 water in the third experiment is probably a typographical error for 0-155.
But 0-5095 of the salt furnished less carbonic acid than 0-430. This must be
a mistake, which affects the quantity of carbon, which of course acts upon the
azote and the oxygen. Liebig's numbers are
Carbon, . . 29-830
Hydrogen, . . 4-406
Azote, . . 25-913
Oxygen, . . 39-851
100
Numbers coming very near those deduced from the formula C8 H7 Az3 O8.
52 ANIMAL ACIDS CONTAINING AZOTE.
When dialurate of ammonia is moistened with dilute sulphuric
acid, that acid combines with the ammonia, and a matter scarcely
crystalline remains, which, when dissolved in water, disappears
altogether before it can be freed from sulphuric acid. The water
employed in washing it deposits, after an interval of some hours,
transparent and brilliant crystals of alloxantin. The liquor
freed from sulphuric acid by carbonate of barytes, and concen-
trated, gives a mother liquor, which, being mixed with nitric acid
and set aside for some hours, does not deposit nitrate of urea ;
but it concretes into transparent prisms similar to oxalic acid.
Dialurate of ammonia dissolved in hot muriatic acid gives on
cooling a number of crystals similar to those of alloxantin, but
differing decidedly in their shape. The muriatic acid solution
contains urea.
After having saturated a boiling solution of alloxane with sul-
phuretted hydrogen, and after ascertaining that the whole allox-
ane had been converted into the new product, the liquid was
concentrated in a retort out of the contact of air. On cooling
there was deposited a thick white opaque crust, having brilliant
facets. This crust became red when dried. It was very soluble
in cold water, had an acid reaction and taste, reduced oxide of
silver, gave with barytes a violet-coloured precipitate, and with
carbonate of ammonia, a little ammoniacal salt after an interval
of some time.
When it is dissolved in boiling water or muriatic acid, the so-
lution, on cooling, deposits transparent crystals similar to allox-
antin. The mother liquor scarcely, if at all, reduces the salts of
silver. On the addition of ammonia and nitrate of silver, it
gives a white precipitate which, by the action of heat, becomes
dark-purple, without being reduced. This mother water gives
a white precipitate with barytes water.
Wohler and Liebig distinguish, by the name of urile, the hy-
pothetical substance which they suppose to constitute uric acid,
when combined with urea : And it has been stated in a preced-
ing section of this chapter, that they consider the constitution of
urile to be C8 Az2 O4. Now
If to one atom urile "... . C8 Az2 O4
We add four atoms water, . H4 O4
We obtain an atom of dialuric acid, C8 H4 Az2 O'
THIONURIf ACID. 53
SECTION JX. OF TIIIONURIC ACID.
This remarkable acid was discovered by Wohler and Liebig
during their researches on uric acid in 1838.*
If we add sulphurous acid to a cold saturated solution of allox-
ane, it loses its smell. When to such a solution, containing a
slight excess of sulphurous acid, we add as much ammonia as will
saturate the acid, heat the mixture, and keep it boiling for a
short time, it deposites on cooling a considerable quantity of
brilliant quadrangular plates. The best method of preparing
this substance on a large scale, is to take sulphate of ammonia
previously mixed with an excess of carbonate of ammonia, to
add to it a solution of alloxane, to raise the mixture to the boil-
ing point, and keep it boiling for half an hour. The salt thus
obtained is a combination of thionuric acid and ammonia. When
dry, it is in thin plates having a strong pearly lustre, soluble in
water and again crystallizable without any other alteration than
the assumption of a red colour. At 212°3 its loses its water and
becomes rose red.
Dr Gregory of Aberdeen has given the following process as
the easiest for preparing thionurate of ammonia. Take a
pretty strong cold solution of alloxan, add to it half its volume
of a strong solution of sulphite of ammonia, with a little free am-
monia, boil for five minutes. On cooling, a large quantity of
thionurate of ammonia is deposited in beautiful silvery scales.
They are to be slightly washed and dried by pressure.
If we raise the aqueous solution of this salt to the boiling
temperature, and pour into it a solution of acetate of lead, a gela-
tinous precipitate falls, which, on cooling, assumes the form of fine
needles, arranged concentrically, and having sometimes a white,
sometimes a red colour, This is thionurate of lead. By mixing it
with water and passing a current of sulphuretted hydrogen gas
through the mixture, the lead is separated, while the acid dis-
solves in the water. On evaporating the aqueous solution in a
gentle heat, the acid is deposited white and crystalline, though
the shape of the crystals cannot be determined.
Thionuric acid does not absorb moisture from the atmosphere.
It has a decidedly sour taste, and reddens vegetable blues.
When we boil its aqueous solution, the acid is decomposed, being
* Ann. de Chiin. et de Phys. Ixviii. 253.
54 ANIMAL ACIDS CONTAINING AZOTE.
converted into sulphuric acid and uramile.* It becomes muddy
during the boiling, and concretes into a silky mass of uramile,
while the sulphuric acid remains dissolved in the water.
Though thionuric acid contains sulphuric acid, yet the or-
dinary reagents are incapable of detecting that acid in thionurate
of ammonia. The salts of barytes throw down a thick, flocky,
gelatinous precipitate, which is soluble in muriatic acid. The
salts of lead behave in the same manner.
A solution of thionurate of ammonia mixed cold with muriatic,
sulphuric, or nitric acids, undergoes no alteration at the com-
mon temperature, but when boiled for a few minutes, it becomes
muddy, and concretes into a white magma, consisting of micro-
scopic needles, having a satiny lustn\ This precipitate contains
no sulphuric acid, but consists of uramile. After this decom-
position, the sulphuric acid may be discovered in the liquor by
the usual reagents.
The thionurate of lead being analyzed in Liebig's laboratory,
was found to be composed as follows ;
Carbon, . 10-83 or 8 atoms = 6 .or per cent, 10'7
Hydrogen, . 1*04 or 5 atoms = 0-625 ... 1-1
Azote, . 9-47 or 3 atoms — 5-25 ... 9-3
Oxygen, . 10-83 or 6 atoms — 6-00 ... 10-7
Sulphuric acid, 18-05 or 2 atoms = 10-00 ... 17.9
Oxide of lead, 49-78 or 2 atoms = 28-00 ... 50-3
55-875 100-0
If we admit, with Wohler and Liebig, that the salt is a dithi-
onurate, it is obvious that the constitution of thionuric acid is Cs
H5 Az3 O6 + 2 (S O3) = 29-875. This conclusion was con-
firmed by a careful analysis of thionurate of ammonia. Between
the tube filled with chloride of calcium, and that containing the
caustic potash, a tube was interposed filled with peroxide of lead.
This peroxide absorbed the sulphurous acid given out, and con-
verted it into sulphate of lead. The mean of three analyses gave
the constituents of the salt as follows :
* This product of uric acid will be described in a subsequent chapter.
4
THIONURIC ACID. 55
Carbon, . 17-84 or 8 atoms =6 or per cent. 17-45
Hydrogen, . 4-90 or 13 atoms = 1-625 ... 4-72
Azote, . 26-01 or 5 atoms = 8-750 ... 25-45
Oxygen, . 22-78 or 8 atoms = 8-000 ... 23-28
Sulphuric acid, 28-47 or 2 atoms = 10-000 ... 29-10
100 34-375 100
If from the preceding constituents, C8 H13 Az5 O8 + 2 (S O3)
We subtract 1 atom thionuric acid, C8 H5 Az3 O6 + 2 (S O3)
There will remain, . . H8 Az2 O2
From this remainder subtract 2 atoms
water, H2 O2
There will remain, . . H6 Az2 which is equal
to 2 atoms ammonia.
So that thionurate of ammonia consists of
1 atom thionuric acid, C8 H5 Az3 O6 2 (S O3)
2 atoms ammonia, . H6 Az2
2 atoms water, . H2 O2
C8 H13 Az5 O8 + 2 (S O3)
We see that hydrated thionuric acid contains two atoms water,
or it is C8 H7 Az3 O8 + 2 (S O3) = 32-125.
Thionurate of lime is obtained by mixing together hot solu-
tions of thionurate of ammonia and nitrate of lime. It separates
under the form of small short prisms, having a satiny lustre. It
is composed of
1 atom thionuric acid, . 29-875
2 atoms lime, . . 7-000
36-875
Thionurate of zinc constitutes small aggregated crystals, which
have a lemon- yellow colour. It is very soluble in water, and is
obtained by mixing a salt of zinc with a solution of thionurate of
ammonia.
A hot solution of thionurate of ammonia mixed with sulphate
of copper gives a brown precipitate, approaching to yellow, which
is obviously protoxide of copper. By the action of heat, it dis-
solves completely into a yellowish-brown liquid, and separates
again on cooling in an amorphous state.
56 ANIMAL ACIDS CONTAINING AZOTE.
When thionurate of ammonia is mixed with nitrate of silver,
the oxide is reduced to the metallic state, and the silver is depo-
sited on the inside of the tube, giving it the appearance of a mir-
ror.
Thionurate of barytes, recently precipitated, even from a di-
lute solution, has the form of a gelatinous mass, which gradually
becomes opaque and crystalline. When boiled with nitric acid,
this salt gives sulphate of barytes, and no sulphuric acid remains
free. This shows that the salt is a compound of one atom thio-
nurie acid and two atoms barytes.
The formation of thionuric acid from alloxane and sulphurous
acid is easily explained.
1 atom alloxane is . C8 H4 Az2 O10
1 atom ammonia, , , H3 Az
2 atoms sulphurous acid," ... O4 S2
Making altogether, . C8 H7 Az3 O14 S2
1 atom thionuric acid, ;^ C8 H5 Az3 O12 S2
2 atoms water, . » . H2 O2
Making together, . C8 H7 Az3 O14 S2
From this we see that two atoms sulphurous acid and one atom
©f ammonia unite with one atom of allophane, and the product
is one atom of thionuric acid and two atoms of water.
Wohler and Liebig seem to be of opinion that the sulphurous
acid in thionuric acid is converted into sulphuric acid. But there
seems no evidence for this. We see only that the elements of
two atoms sulphurous acid and one atom ammonia unite with an
atom of alloxane, and form thionuric acid. If it existed in the
state of sulphuric acid, barytes surely would be able to detect its
presence. But we have seen that this is not the case.
SECTION X. OF URAMILIC ACID.
This acid also was discovered by Wohler and Liebig during
their important investigation of uric acid and its products in
1838.*
It may be obtained by mixing a cold solution of thionurate of
ammonia with a small quantity of sulphuric acid, and evaporating
the mixture in a gentle heat. The uramile separates by little
* Ann. de Chim. et cte Phys. lxviii.308.
3
URAMILIC ACID, ^7
and little, and is then decomposed by the free acid. The solu-
tion, when concentrated, becomes yellow, and in twenty-four
hours crystals of uramilic acid are deposited. The success of this
process depends upon the quantity of acid added to the thionu-
rate of ammonia. With too little sulphuric acid, we obtain by
evaporation a pap of small flocky crystals, which are white, very
confused, and consist of bithionurate of ammonia. It is always
more advantageous to prepare this salt first. For we obtain a
considerable quantity of uramilic acid by dissolving it anew in
sulphuric acid and evaporating.
If we employ too much sulphuric acid, we do not obtain a
trace of uramilic acid, but when the liquid is left long exposed
to the air, transparent crystals are deposited, which have the form
and the characters of dimorphous alloxantin. These crystals are
oblique four-sided prisms, belonging probably to the trimetric
systems. They are formed of the four faces distinguished by M.
Gr. Rose by the letter g, and terminated by a perpendicular
plane. This base is so large in proportion to the faces g, that
the crystals have the form of tables. The obtuse angle of the base
is about 121°. Alloxantin, from the dialurate of ammonia, has
the same crystalline form. The crystalline shape of alloxantin
is also an oblique four-sided prism belonging to the same sys-
tem ; but the obtuse angle of the base is only 105°.
When uramilic acid is deposited slowly from a moderately
concentrated solution, it forms pretty large four-sided prisms,
which are colourless and transparent, and have a vitreous lustre.
From a hot saturated solution, it crystallizes in fine silky
needles. When dried by means of heat, it assumes a rose-red
colour, without losing any sensible weight. Its solution in water
has a feebly acid reaction. It combines with ammonia and the
fixed alkalies, and forms with them crystallizable salts. The salts-
of lime and barytes are not decomposed by free uramilic acid,
but the addition of ammonia determines the precipitation of thick
white matter, which is again dissolved by the addition of a great
quantity of water. Uramilic acid does not throw down nitrate
of silver, but if we previously combine the acid with ammonia.,
we obtain a thick white bulky precipitate.
Uramilic acid dissolves in concentrated sulphuric acid without
the evolution of any gas or any change of colour. When long
boiled with dilute sulphuric or muriatic acid it undergoes an al~
ANIMAL ACIDS CONTAINING AZOTE.
teration. The liquid, after a certain time, acquires the property
of precipitating barytes water violet, whereas at first it gives with
it a white precipitate. The acid liquor gives crystals of dimor-
phous alloxantin.
The reaction of uramilic and nitric acid is remarkable. It
dissolves in that acid at first without the evolution of any gas ;
but if we boil it with concentrated nitric acid, nitrous acid is dis-
engaged. The liquid becomes yellow when concentrated, and
gives a notable quantity of white crystalline plates, which are
soluble in hot water and crystallize on cooling. With this they
form a yellow solution and acetic acid throws down a white pow-
der. This new substance has not been sufficiently examined.
It resembles xanihic oxide.
When uramilic acid is heated with oxide of copper it furnishes
azotic and carbonic acid in volumes, which are to each other as 1
to 3-2. The acid being subjected to an analysis in Liebig's labo-
ratory, the constituents obtained were the following : —
Carbon, 31-64 or 16 atoms =12 or per cent. 32-43
Hydrogen, 3-63 or 10 atoms = 1-25 ... 3-37
Azote, . 23-07 or 5 atoms = 8-75 ... 23-65
Oxygen, 41-66 or 15 atoms = 15-00 ... 40-55
100-00 37 100-00
These atomic numbers were pitched upon by Wohler and Liebig
from a supposed relation between nramile and uramilic acid.
Uramile is C8 H5 Az3 O6. Now from
2 atoms uramile, ... C16 H10 Az6 O12
Subtract 1 atom ammonia, . . H3 Az
We have . . •£& C16 H7 Az5 O12
Add 3 atoms water, . H3 O3
And we get , . . C16 H10 Az5 O15
which is an atom of uramilic acid.
Liebig attempted to determine the true atomic weight of ura-
milic acid by analysing uramilate of silver. But in drying the
salt it was accidentally exposed to too high a temperature, and
became black. This made the proportion of silver in the salt
greater than it ought to have been. It was composed of
HIPPURIC AND CHOLEIC ACIDS. 59
Uramilic acid, . 23-08
Oxide of silver, . 76-92
100-
If we admit that in uramilic acid the three atoms water substi-
tuted for ammonia and the two atoms of water in the two atoms
of uramile are replaced by 5 atoms of oxide of silver, the con-
stitution of the salt would be,
Acid, . . . 31-375 or per cent 30-29
Oxide of silver, . 72-5 69*71
100-
Now this does not deviate very far from the result of the analy-
sis of uramilate of silver.
SECTION XI. OF HIPPURIC ACID.
This acid has been described in the Chemistry of Vegetable
Bodies, (p. 46.) No additional facts respecting this acid, so far
as I know, have been discovered since the publication of that
volume, except the formation of hippuric ether, an account of
which will be given in the appendix.
Its constitution is C18 H8 Az O5 = 21-25.
SECTION XII. OF CHOLEIC ACID.
This acid constitutes the greatest part of ox bile. It had been
considered as an acid by the older chemists and physiologists.
Berzelius gave it the name of biliary matter, and Thenard that
of picromel. But from the recent analysis of ox bile by M. De-
ma^ay* it appears that the old opinion advanced by Cadet, that
bile is of a soapy nature, is after all, the true one. Dema^ay
has shown that the essential constituents of bile are soda, and an
oily acid to which he has given the name of choleic.} This acid
may be obtained pure from ox bile by the following process : —
Evaporate the bile to dryness over the steam-bath and digest the
dry residue in alcohol. The choleate of soda will be dissolved, while
the mucus mixed with the bile is left behind. Distil off the al-
cohol by 'a steam heat, and dissolve the residue in water. To
* Ann. de Chim. et de Phys, Ixvii. 177.
f From £ox», bile.
60 ANIMAL ACIDS CONTAINING AZOTE.
this solution add as much sulphuric acid as will exactly neutra-
lize all the soda in the solution, digest for two days in a mode-
rate heat, agitating frequently. Then evaporate to dryness over
the water-bath, and digest the residue in alcohol. The choleic
acid is dissolved while sulphate of soda in crystals remains be-
hind. Finally, distil off the alcohol, substituting water, and
evaporating to dryness over the steam-bath.
Choleic acid thus obtained possesses the following properties :
It is a yellow, spongy, pulverulent matter, which rapidly absorbs
moisture from the atmosphere. Its taste is very bitter, with an
impression of sweetness. Its powder irritates the nostrils and
throat. It is insoluble in ether; but very soluble in alcohol,,
and pretty soluble in water.
It cannot be distilled without decomposition. When heated
it melts, swells up and burns with flame, giving out smoke and
leaving a bulky charcoal, which may be burned completely with-
out leaving any residue. It melts imperfectly at 248°, and is
not decomposed till heated considerably above 400°.
Its solutions redden litmus-paper, and decompose the alka-
line and earthy carbonates with effervescence. But in this
way we can form only bicholeates. The choleic acid thus
combined with a base is precipitated by acetic acid; though
that acid does not act on bile. The acids throw down choleic
acid in flocks, which soon collect into a brown viscid fluid. Mu-
riatic, sulphuric, and phosphoric acids decompose it into choloidic
acid and taurin* Nitric acid decomposes it, deutoxide of azote
is evolved, and a peculiar white substance formed. The caus-
tic fixed alkalies decompose it into cholic acid and ammonia.
M. Demar9ay analyzed it by oxide of copper and obtained,
Carbon, . 62-82 ,
Hydrogen, . 8.91
Azote, « 3.30
Oxygen, . 24-97
100-
He analyzed choleate of soda, and obtained for the atomic
weight of choleic acid 50-213. The number of atoms which agree
best with the atomic weight and analysis are,
* The choloidic acid was described in the last chapter. Taurin is a crystal-
line substance obtained from bile, which will be described in a subsequent chap-
ter.
C1IOLEIC ACID. ()1
41 atoms carbon, = 30-75 or per cent. 63-23
33 atoms hydrogen, — 4-125 ... 8*48
1 atom azote, - =1-75 ... 3.60
12 atoms oxygen, =12-00 ... 24-69
48-625 100-
If we suppose the acid in the choleate of soda analyzed to re-
tain 2 atoms of water, the atomic weight will be 50.875, which
approaches the result of the analysis of Demarcay, 1 •£• atom wa-
ter would make the atomic weight 50-3125, which agrees very
nearly with the actual analysis of choleate of soda.
A few only of the salts of choleic acid have hitherto been ex-
amined. The following are the facts which have been ascer-
tained.
1. Choleate of Soda. — To form this salt, (which constitutes
bile,) alcoholic solutions of choleic acid and of soda were mixed
together till the reaction became alkaline. Then a current of
carbonic acid gas was passed through the solution for several
hours. Being left at rest, the carbonate of soda separated in
small crystals. The liquid was filtered and evaporated to dry-
ness. The residue readily dissolved in alcohol of 0-800 without
leaving any residue. Hence it was pure.
The reaction of this salt is weakly alkaline. It has the taste
and properties of bile. When evaporated it leaves a brown re-
sinous magma, similar in appearance to choleic acid. When
dry it forms a yellow, very light, friable mass, which attracts hu-
midity from the atmosphere. It is soluble in all proportions in
water and alcohol. It melts at the same temperature as cho-
leic acid, and concretes into a brown and very friable mass.
When heated it behaves like bile.
Bicholeate of Soda may be obtained by digesting choleic acid
over bicarbonate of soda.
2. Choleate of Potash may be formed in the same way as cho-
late of soda, and possesses the same properties.
3. Choleates of Barytes and Strontian are soluble in alcohol
and water. When evaporated they leave a resinous residue
like all the choleates.
4. With oxide of lead choleic acid combines in two proportions.
When a solution of nitrate of lead is dropt into choleate of soda
a neutral choleate is formed. When diacetate of lead is em-
)2 ANIMAL ACIDS CONTAINING AZOTE.
ployed a dicholeate of lead falls. Both are nearly insoluble in
water, but soluble in acetic acid. They have a resinous con-
sistence.
5. Nitrate of silver forms with choleate of soda a white preci-
pitate, which by washing is converted into dicholeate of silver.
After being dried in vacuo over sulphuric acid, its constituents
were,
Choleic acid, 50*58
Oxide of silver, 29-
Now 29 is the weight of two atoms of oxide of silver. Hence
the salt is a dicholeate.
SECTION XIII. OF CHOLESTERIC ACID.
Cholesterin, a substance having some resemblance to sperma-
ceti, and a very frequent ingredient in gall-stones, seems to have
been first particularly noticed by Gren in 1788.* In the year
1817, the action of nitric acid upon this substance was particu-
larly examined by Pelletier and Caventou.f They ascertained
that by this action a peculiar acid was formed, to which they
gave the name of cholesteric. The subject was again resumed
by Pelletier in 1832.} He subjected it to an ultimate analysis
and determined its constituents.
Cholesterin was treated with its own weight of concentrated
nitric acid. The acid when assisted by heat speedily dissolved
the cholesterin, while at the same time abundance of deutoxide
of azote was evolved. When the solution cooled a yellow-co-
loured matter separated, and when the liquid swimming over this
deposit was diluted with water, an additional portion of the same
substance was separated. This yellow substance was not sensi-
bly soluble in water ; but on elevating the temperature, it swam
like butter upon the surface of the water. When well washed
it was deprived of all acid taste ; but had a peculiar though
slight stypticity. Yet it was capable of reddening litmus-paper,
and of saturating the alkaline bases with considerable energy.
To purify the cholesteric acid thus obtained Pelletier and Ca-
ventou proceeded in the following manner : A portion of it was
» Diss. contin. duas observations circa calculos, Sfc. Hal. 1788, 62. As
quoted by L. Gmelin, Handbuch der Theoretischen Chemie, ii. 504.
t Jour, de Pharmacia, iii. 292.
{ Ann. de Chim. et de Phys. li. 189.
CHOLESTERIC ACIU. 63
mixed with water and heated till the azote melted. A little car-
bonate of lead was now added and the mixture boiled for seve-
ral hours, changing repeatedly the water. The liquids when eva-
porated gave all of them a little cholesterate of lead ; but none
of them, except the first, gave any nitrate of lead. The acid thus
treated was digested in alcohol, which dissolved it, leaving the cho-
lesterate of lead and carbonate of lead untouched. By evaporating
this solution, the cholesteric acid was obtained in a state of purity.
Cholesteric acid is soluble in alcohol, and when the liquid is
left to spontaneous evaporation, the acid crystallizes in white
needles. But when concreted into an uncrystallized mass, its
colour is orange-yellow. Its smell has some analogy to that of
butter, and its taste is slightly styptic. It melts, when heated, to
136°. When heated above 212°, it is decomposed into oil,
water, carbonic acid, and carburetted hydrogen. Its specific gra-
vity is higher than that of alcohol, but lower than that of water.
It is slightly soluble in water, for that liquid when left in contact
with it acquires the property of reddening litmus-paper. It is
more soluble in hot than in cold alcohol.
It readily combines with the bases, and forms salts. The acids
have little action on it. Concentrated sulphuric acid becomes
first red, and then chars it when left long in contact with it.
Nitric acid dissolves it without alteration. It does not act upon
it so as to produce decomposition even when boiled with it
When evaporated, the cholesteric acid remains, possessing all its
properties. Acetic acid has no action on it, and is incapable of
dissolving it. It is very soluble in sulphuric and acetic ethers.
The volatile oils dissolve it readily even while cold, but the fixed
oils do not act upon it.
From the analysis of cholesterate of bary tes made by Pelletier
and Caventou it follows that it is composed of
Cholesteric acid, . 64- or 16 '9
Barytes, . . 36- or 9*5
100
Cholesteric acid was analyzed by Pelletier who obtained,
Carbon, . 54*93
Hydrogen, . 7 '01
Azote, - 4*71
Oxygen, . 33-35
100-00
64 ANIMAL ACIDS CONTAINING AZOTE.
The number of atoms which agrees best with this analysis and
with the atomic weight is
13 atoms carbon, = 9-75 or per cent. 54-34
10 atoms hydrogen, = 1-25 ... 6'50
£ atom azote, =0-875 ... 4-90
6 atoms oxygen, =6-0 ... 33-56
17*875 100-
The analysis of cholesterate of strontian is considered by Pel-
letier as the most accurate. It was found composed of
Cholesteric acid, 100- or 16-5
Strontian, . 36-98 or 6-5
This would make the atomic weight of cholesteric acid 16-5,
which does not deviate much from that obtained by the ultimate
analysis.
All the cholesterates are more or less coloured. The alkaline
cholesterates are very soluble and deliquescent, but the earthy
and metalline cholesterates are very little or not at all soluble
in water. They are decomposed by all the mineral and most of
the vegetable acids, if we except carbonic acid. The alkaline
cholesterates precipitate all the metallic solutions, and the preci-
pitates vary in colour according to the kind of metal or the de-
gree of its oxydizement.
1. Cholesterate of potash has a brownish-yellow colour, does
not crystallize, is very deliquescent, and does not dissolve in al-
cohol or ether. It is incapable of uniting with a second dose of
the acid. When this salt is decomposed by sulphuric or any other
acid, the cholesteric acid separates in white flocks, which float
upon the surface of the liquid. When heat is applied to this
salt, the acid undergoes decomposition. There pass over water,
oil, and carburetted-hydrogen gas, while carbonated-potash re-
mains in the retort. No hydrocyanic acid is evolved during this
decomposition.
2. Cholesterate of soda resembles the preceding salt so exactly
that we can only distinguish them by separating the base, and
ascertaining its nature
3. Cholesterate of ammonia, obtained by directly uniting the
constituents of the salt together, has the same taste, colour, and
smell, as the two preceding species ; and its reactions are similar.
4. Cholesterate of barytes is easily obtained by double decom-
CHOLESTERIC ACID. 65
position. It is very little soluble in water. When newly pre-
cipitated, it has a lively red colour ; but on drying it becomes
of a dark muddy red. It has neither taste nor smell. Accord-
ing to the analysis of Pelletier and Caventou, it is composed of
Cholesteric acid, . 16'9
Barytes, . . 9-5
They found that cholesteric acid required for its saturation about
three and a-half times as much barytes as sulphuric acid does. Ac-
cording to that statement, its atomic weight should only be 17*5.
5. Cholesterate of strontian may be obtained, like the preced-
ing salt, by double decomposition. It has an orange-red colour,
is almost insoluble in water, and is destitute of taste and smell.
Pelletier and Caventou analyzed it after it had been dried in the
temperature of 212°, and obtained,
Cholesteric acid, . 16*5
Strontian, . . 6*5
6. Cholesterate of lime was obtained by mixing solutions of
chloride of calcium and cholesterate of potash. It has a brick-
red colour, is destitute of taste and smell, and is more soluble in
water than the two preceding species.
7. Cholesterate of magnesia is obtained by double decomposi-
tion. It has a deep brick- red colour, and is insoluble in water.
8. Cholesterate of alumina may be obtained by mixing together
solutions of alum and cholesterate of potash. When newly pre-
cipitated it has a beautiful red colour, but becomes dark and
dull on drying.
9. Cholesterate of platinum is obtained by mixing solutions of
chloride of platinum and cholesterate of potash. It has a brown
colour, is insoluble in water, and very heavy.
10. Cholesterate of silver has an orange-red colour, which be-
comes dull on drying.
11. Cholesterate of lead was obtained by mixing nitrate or
acetate of lead with cholesterate of potash. It has a deep brick-
colour, but loses its beauty on drying. It is insoluble in water,
but dissolves in acetic acid, or rather it is decomposed by that
acid.
Pelletier and Caventou found that 100 parts of this salt yield-
ed 100 parts exactly of sulphate of lead. Now 100 sulphate of
lead contain 73*68 of oxide of lead. Hence the cholesterate of
lead must be a compound of
(i() ANIMAL ACIDS CONTAINING AZOTE.
Cholesteric acid, . 26-32 or 5 or 17-875
Oxide of lead, . 73-68 or 14 or 50 - 3^ atoms.
It was probably a mixture of tetrakis-cholesterate of lead and
cholesterate of lead.
12. Cholesterate of mercury. — When cholesterate of potash is
poured into proto-nitrate of mercury a black precipitate falls.
The colour of the precipitate is deep-red when the mercurial
salt is the per-nitrate.
13. Cholesterate of copper. — When cholesterate of potash is
poured into any salt of copper an olive-coloured precipitate falls,
without taste or smell, and quite insoluble. According to the
analysis of this salt by Pelletier and Caventou it is composed of
Cholesteric acid, . 5 or 15 — 1 atom
Oxide of copper, . 15 or 45 — 9 atoms.
It is very unlikely that this analysis can have been made upon
any thing else than a mixture. At least no analogous compound
has hitherto been observed.
14. Cholesterate of iron. — When cholesterate of potash is
poured into sulphate of iron a deep-brown precipitate falls, which
is slightly soluble in water. On exposure to the air it becomes
yellow by absorbing oxygen. This salt was analyzed by Pelle-
tier and Caventou, and found composed of
Cholesteric acid, . 11-1 or 16*65 — 1 atom
Oxide of iron, . . 4*5 or 6-75 = 1^ atom.
From this analysis it would appear that the salt was a subsesqui-
cholesterate of iron.
15. Cholesterate of Zinc is obtained by double decomposition.
It has a fine red colour, and is slightly soluble in cold water, and
still more soluble in boiling water.
1 6. Cholesterate of cobalt is obtained by double decomposition,
and has a yellow colour similar to that of plain Spanish snuff.
17. Cholesterate of tin is also yellow, but lighter, and having
a tint of orange.
18. Cholesterates of nickel and manganese have a bistre colour.
SECTION XIV. OF HYDROMELONIC ACID.
This acid was discovered by M. L. Gmelin in 1835, and nam-
ed hydrojnelonic, because it is composed of one atom of melon
and one atom of hydrogen.*
* Annalen der Pharmaeie, xyi. 252.
HYDROMELONIC ACID. 67
In preparing sulpho-cyanic acid, when the mixture of prussiate
of potash and sulphur had been heated too high, he occasionally
got small quantities of another salt. In such cases, when the
iron had been precipitated, and the filtered liquid, after having
been sufficiently concentrated, was set aside, white cauliflower-
looking crystals of this new salt were deposited. These being
again dissolved in hot water, crystallized, exposed to pressure,
and washed with hot alcohol till the salt no longer struck a red
with the persalts of iron, were considered as freed from all ad-
mixture of sulpho-cyanate of potash. When this salt was dis-
solved in boiling water, and the solution mixed with muriatic,
sulphuric, or nitric acid, a dirty-white gelatinous precipitate fell,
which dried into a yellow powder. This precipitate is a hydrate
of hydromelonic acid. It is slightly soluble in cold water, but
more soluble in that liquid when hot. It dissolves also in alco-
hol. It is destitute of taste and smell, but has a feeble acid re-
action. When heated it decrepitates slightly, and leaves melon,
which may also be driven off by continuing the heat. It dis-
solves readily in nitric acid, and the solution may be evaporated
without decomposing the hydromelonic acid. It dissolves also
in sulphuric acid. Hydromelonate of po ash effervesces when
heated with nitric acid, dissolves in water, and is decomposed by
acids.
To analyze this acid, Grmelin employed hydromelonate of lead,
dried in the open air at 60°. 100 parts of this salt exposed to a
heat of 212°, lost 11 '08 7 parts of water ; and when the heat was
raised to 248°, it suffered an additional loss of 3-043 ; making
the whole water in the salt amount to 14*13 per cent. 100 parts
of the same salt being decomposed by sulphuric acid, left 6 2 '3 8
of sulphate of lead, equivalent to 45^946 of oxide of lead. Hence
the constituents of the salt were
Hydromelonic acid, . 39*906 or 12-154 = 1 atom.
Oxide of lead, . . 45*964 or 14 — 1 atom.
Water, - . . 14*130 or 3*304 = 4 atoms.
100-000
This analysis gives as the atomic weight of hydromelonic acid,
12*154.
Gmelm analyzed hydrous hydromelonate of lead by means of
oxide of copper, and obtained
()8 ANIMAL ACIDS CONTAINING AZOTE.
Carbon, . 14720 or 6 atoms = 4*5 or per cent. 14*94
Hydrogen, . 2-037 or 5 atoms = 0-625 ... 2-08
Azote, . . 23-010 or 4 atoms = 7-0 or per cent 23-24
Oxygen, . 14-269 or 4 atoms — 4-0 ... 13-18
Oxide of lead, 45-964 or 1 atom = 14-0 ... 46-46
100-000 30-125 100*
But it is clear from the preceding analysis, that the salt thus
analyzed contained 14*13, or 4 atoms of water. Subtracting
this there remain for the constituents of hydromelonic acid
6 atoms carbon, = 4-5
1 atom hydrogen, 0-125
4 atoms azote, — 7*000
11*625
Thus it appears that hydromelonic acid is composed of
1 atom melon, (C6 Az4) = 11*5
1 atom hydrogen, — 0*125
11-625
Hydromelonate of Potash is a yellowish white opaque cohesive
mass, having a bitter taste. When heated, it gives out carbo-
nate and hydrocyanate of ammonia, and melts into a clear yel-
low liquid, which concretes on cooling. When heated with ni-
tric acid it froths, but without effervescence. It dissolves in hot
sulphuric acid, and is again precipitated by water. It is scarcely
soluble in cold, but very soluble in hot water. Alcohol scarcely
acts upon it, even at a boiling temperature. It is decomposed by
all the strong acids, hydromelonic acid being disengaged. The
earthy alkaline salts, earthy salts, and most of the metalline salts
occasion a precipitate in hydromelonate of potash, consisting of
flocks most commonly white. But the salts of oxide of chromi-
um give a bluish white ; those of peroxide of iron, a light brown ;
those of oxide of cobalt, a rose red ; those of oxide of nickel, a
bluish white ; those of suboxide of copper, a whitish yellow ; those
of black oxide of copper, a sisken green ; those of oxide of gold,
a yellowish white ; and those of oxide of platinum, a brownish
yellow precipitate.
It has been ascertained that when hydromelonic acid is heated
in contact with a metallic oxide, water is formed, and the melon
unites with the metal, constituting a melonet. The only one of
CEREBR1C ACID. 69
these melonets hitherto examined is the melonet of potassium. It
may be formed by fusing sulphocyanate of potash in a porcelain
crucible at a red heat, adding melon as long as an evolution of
bisulphuret of carbon and sulphur is observed. A brown opaque
glassy mass is obtained, which, being dissolved in boiling water,
and the solution allowed to cool, deposits hydrated crystals of
melonet of potassium. It may be formed also by fusing five parts
of butter of antimony with eight parts of sulphocyanate of potash,
and removing by boiling water the soluble portion of the resi-
due, after the sulphur and bisulphuret of carbon have been dri-
ven off.
It crystallizes from its aqueous solution in fine needles, which
collect into large flocks. A concentrated solution congeals into
a white mass, not easily dissolved in cold water. The crystals
contain water of crystallization, which they lose when heated.
They then fuse without loss of weight into a transparent yellow
glass. The solution of this compound is tasteless, and precipi-
tates all earthy and metalline salts.
SECTION XV. OF CEREBRIC ACID.
This substance, which constitutes an important constituent of
the brain, was first noticed by Vauquelin in his chemical analy-
sis of the brain, published in 1812 * He gives it the name of
white fatty matter ; but did not obtain it in a state of purity ;
Kiihn also noticed it under the name oimyelocone. f Couerbe, in
1834, obtained it also, though not in a state of complete purity,
and gave it the name of cerebrote. J In 1841 it was again ex-
amined by Fremy, § who brought it to a state of comparative
purity, discovered its acid properties, and gave it the name of
cerebric acid.
Couerbe's method of obtaining it was to digest the matter of
brain in ether, till every thing soluble in that liquid was remov-
ed, the residue was treated with boiling alcohol, as long as any
thing continued to dissolve. The alcohol, on cooling, deposited
a white 'matter consisting chiefly of cerebrote and cholesterin.
Cold alcohol dissolved the latter of these substances, and left
the cerebrote. But Fremy ascertained that cerebrote obtained
in this way still contained sensible quantities of cerebrate of lime
* Ann. de Chim. Ixxxi. 37, or Annals of Philosophy, i. 332.
f Dissert, de Cholestearine, p. 20. \ Ann, de Chim. et de Phys. Ivi. 171
§ Jour, de Pharmacie, xxvii. 439.
70 ANIMAL ACIDS CONTAINING AZOTE.
and albumen. He succeeded in obtaining it pure by the follow-
ing process.
He digested the mass obtained by evaporating the etherial solu-
tion of the brain in a great quantity of ether. By this means a
white substance is precipitated, which is isolated by decantation,
and which, when exposed to the air, is transformed into a waxy
and fatty matter. This precipitate contains cerebric acid, often
combined with phosphate of lime, or soda, and with albumen*
It was dissolved in boiling absolute alcohol slightly acidulated
by sulphuric acid. The sulphates of lime and soda, with some
albumen, remained in suspension, and were separated by the fil-
ter. The cerebric and oleophosphoric acids were held in solution,
and were deposited as the liquid cooled. The precipitate was
washed with cold ether, which dissolved the oleophosphoric acid,
and left the cerebric. Finally, the cerebric acid was dissolved
in boiling ether, and crystallized three or four times. It was
then pure.
Thus obtained it is white, and composed of small crystalline
grains. It is entirely soluble in boiling alcohol, almost insolu-
ble in cold ether, but more soluble in that liquid when boiling
hot. It has the remarkable property of swelling like starch in
boiling water, though it is quite insoluble in that liquid. When
strongly heated it melts, but its fusing point is very little lower
than that at which it undergoes decomposition.
When heated in the open air it burns, giving out a characte-
ristic odour, and leaving a charcoal which burns with difficulty,
and which is sensibly acid. Sulphuric acid blackens it. Nitric
acid decomposes it very slowly. When calcined with nitre and
carbonate of potash, no sulphate of potash is formed ; a proof
that it contains no sulphur. But phosphoric acid is always formed
in. such quantities as may be determined.
When heated with an excess of potash, ammonia is disengag-
ed, proving the presence of azote.
This acid was analyzed by Fremy in the usual way. He found
the constituents to be
Carbon, . 66-7
Hydrogen, . 1 0-6
Azote, 2-3
Phosphorus, . 0-&
Oxygen, . 19-5
100-0
CEREBRIC ACID. 71
To determine its atomic weight, he analyzed cerebrate of barytes,
which he had obtained in the following manner : — Cerebric acid
was boiled with water to convert it into a hydrate. An excess
of barytes water was then poured into the liquid, and it was kept
boiling for some time, taking care to exclude carbonic acid gas.
A white, flocky insoluble precipitate fell, which, when washed and
dried, was composed of
Cerebric acid, . 92-2 or 112-29
Barytes, . . 7*8 or 9-5
100-0
Were we to consider the salt as a neutral cerebrate, the ato-
mic weight of cerebric acid would be 112-29. But it is more
probable from analogy that it contains two atoms barytes united
to one atom of cerebric acid. This would make the atomic weight
of the acid 224-58.
The atomic composition agreeing best with this weight, and
with Fremy's analysis is
198 atoms carbon, . — 148-5 or per cent. 66-90
186 atoms hydrogen, . —23-25 ... 10-47
3 atoms azote, . — 5-25 ... 2-36
1 atom phosphorus, . = 2- ... 0-90
43 atoms oxygen, . =43. ... 19-37
222- 100-00
or perhaps 3 (C66 H63 Az O14) + Ph. These numbers corre-
spond sufficiently with the analysis, and make the atomic weight
of the acid 222.
Cerebric acid combines in definite proportions with bases. It
is therefore an acid, though possessed of very little energy.
When heated with dilute solution of potash, soda, or ammonia, it
is not dissolved ; yet it combines with their different bases. These
combinations may be obtained by putting an alcoholic solution
of cerebric acid in contact with these bases. A precipitate im-
mediately falls, almost quite insoluble in alcohol, which consists
of the acid united to the respective bases. Lime, barytes, and stron-
tian combine directly with cerebric acid, and make it lose the
property of forming an emulsion with water. The remaining
cerebrates have not yet been examined.
72 ANIMAL ACIDS CONTAINING AZOTE.
SECTION XVI. OF OLEOPHOSPHORIC ACID.
The presence of this acid in the human brain, and doubtless
in that of the inferior animals, has been lately discovered by M.
Fremy. *
It has been stated in the preceding section, that when the ethe-
rial product of the brain is treated with ether, there remains in
solution a viscid substance which contains oleophosphoric acid,
frequently combined with soda. To obtain the acid we must de-
compose this salt with an acid, and digest the mass in boiling
alcohol, which dissolves the oleophosphoric acid, and lets it pre-
cipitate as it cools. Thus obtained it is always mixed with olein,
which may be removed by anhydrous alcohol. We may free
it from cholesterin, which is often present, by alcohol and ether,
which dissolve the cholesterin more readily than the oleophos-
phoric acid. It has not yet, however, been obtained in a state
of purity. Fremy was not able to free it completely from cho-
lesterin and eerebric acid.
It has usually a yellow colour, like olein. It is insoluble in
water, and swells a little when put into boiling water. It is al-
ways viscid. In cold alcohol it is insoluble, but dissolves rea-
dily in that liquid when at the boiling temperature. It is soluble
in ether.
When placed in contact with potash, soda, or ammonia, it im-
mediately forms soapy compounds similar to the matter extract-
ed from brain when treated with ether. With the other bases
it forms compounds insoluble in water. When oleophosphoric
acid is burnt in the open air, it leaves a strongly acid charcoal,
in which the presence of phosphoric acid may be detected.
When this acid is boiled for a long time in water or alcohol,
it gradually loses its viscidity, and is changed into a fluid oil,
which possesses the characters of pure olein. The water or al-
cohol holds a notable quantity of phosphoric acid in solution.
This decomposition is very slow and incomplete when the oleo-
phosphoric acid is treated with pure water or alcohol, but be-
comes very rapid when these liquids are rendered slightly acid.
It takes place at the common temperature, but very slowly. The
atmosphere has no share whatever in this decomposition.
Olein is soluble in absolute alcohol, but oleophosphoric acid is
quite insoluble in that liquid. This shows that oleophosphorie
* Jour, de Pharm., xxvii. 463.
NITROLEtJCIC ACID. JS
Acid is not a mere mixture of olein and phosphoric acid, but a
compound of the two. But after the oleophosphoric acid has
been boiled in water or alcohol, the olein being separated from
the acid, is readily taken up by absolute alcohol, even without
the application of heat. The olein thus disengaged burns upon
platinum foil without leaving any residue, which is not the case
with oleophosphoric acid.
From these facts it is obvious that oleophosphoric acid is very
easily altered in its nature. Hence the reason why it is frequently
found in a brain quite fresh ; though no traces of it can be dis-
covered after the brain has been left for some time to putrefy ;
but instead of it, much olein and phosphoric acid in a separate
state. M. Fremy is of opinion that this tendency to decomposi-
tion may account for some of the changes which are apt to take
place in a living brain.
Oleophosphoric acid is readily acted on by fuming nitric acid.
Phosphoric acid is dissolved, and a fatty acid swims on the sur-
face of the liquid. The quantity of phosphoric acid determined
in this way varies from 1'9 to 2 per cent
The alkalies added in excess transform the oleophosphoric acid
into oleates, phosphates, and glycerin.
Fremy considers oleophosphoric acid to be a compound of
phosphoric acid and olein. But he could not succeed in his at-
tempts to combine these two bodies artificially. It must be ac-
knowledged that such a compound, if it do exist, is of a very sin-
gular nature. Olein is a compound of oleic acid and glycerin,
in reality a salt, while phosphoric acid is a powerful acid.
SECTION XVII. OF NITROLEUCIC ACID.
This acid was discovered by Braconnot in 1820.* When
minced animal muscle is digested in water till everything solu-
ble is removed, and, after being exposed to pressure, is mixed with
its own weight of concentrated sulphuric acid, it swells up and
dissolves and a little fatty matter swims on the surface, which
must be removed. This mass being mixed with twice its weight
of water and boiled for nine hours, taking care to add water as
fast as it Evaporates, the muscle undergoes decomposition. Am-
monia is formed, which unites with the sulphuric acid, while from
the other constituents of the muscle at least three new principles
* Ann. de Chim. et de Phys. xiii. 118.
74 ANIMAL ACIDS CONTAINING AZOTE,
are formed. These three may be separated from each other in
the following way. Saturate the acid liquid with carbonate of
lime, and filter in order to get rid of the sulphate of lime formed,
and then evaporate to dryness^ A yellowish mass remains, hav-
ing the flavour of boiled meat. If we boil this matter with alco-
hol of O845, two of the three principles are dissolved. The alco-
holic solutions are mixed and distilled. The residue taken out of
the retort is evaporated to dryness, and what remains is treated with
a small quantity of alcohol of 0-83. An extractive looking sub-
stance is dissolved, which attracts moisture from the air, and has
the smell and taste of roasted meat.
The portion insoluble in alcohol of 0-83 has been called by
Braconnot leucin (from Xsuxos, white.) It is a white powder solu-
ble in water and crystallizable. It generally contains some fo-
reign matter, from which it may be freed by cautiously adding
solution of tannin. If, after filtering, we evaporate till a pelli-
cle begins to appear on the surface, and then leave it at rest, a
great number of small round grains are deposited, flat, and hav-
ing an elevated margin so as to resemble some buttons. These
crystals are leucin.
Leucin crackles under the teeth ; its taste resembles that of
boiled meat When heated to 212° it melts and undergoes a
partial decomposition, giving out at the same time the smell of
roast meat. One portion sublimes unaltered in the form of small
white opaque crystalline grains, while at the same time there
comes over into the receiver ammoniacal water and a little em-
pyreumatic oil. Leucin is very soluble in water and but little
soluble in alcohol. But hot alcohol dissolves a greater portion
than it can retain when cold. The aqueous solution of leucin is
not precipitated by diacetate of lead nor by any metalline salt, ex-
cept pernitrate of mercury, which throws it down completely in the
state of a white magma, while the supernatant liquor becomes red.
To obtain nitro-leucic acid the leucin is to be dissolved in ni-
tric acid by means of a gentle heat. A slight effervescence takes
place, but no red vapours appear. When sufficiently concen-
trated the liquid concretes into a mass of white crystals. When
freed from nitric acid by pressure between the folds of blotting-
paper and purified by a second crystallization, these crystals con-
stitute nitroleucic acid.
Its taste is sour but weak. It combines with bases and forms
salts called nitroleucates. Only two of them, nitroleucate of lime
UREA. 75
and of magnesia, have been examined by Braconnot. They crys-
tallize and do not absorb moisture from the atmosphere.
It would be an object of some consequence to examine this
acid more in detail. It is probably analogous to the compound
acid described in the Chemistry of Vegetable Bodies, p. 168.
CLASS II.
OF ANIMAL BASES.
THESE bodies have been hitherto but imperfectly examined
The number of animal bodies which are known to combine and
neutralize acids does not exceed eleven, and, if we except urea,
not one of them has hitherto been subjected to an ultimate ana-
lysis. It is true, indeed, that ammonia is obtained from the ani-
mal kingdoms, and that it is a very decided base. But, for reasons
too obvious to require being stated here, that alkali was described
while treating of the chemistry of inorganic bodies. Here, there-
fore, we shall simply give a list of the principal combinations in-
to which it enters.
CHAPTER II.
OF UREA.
THE substance now known by the name of urea was discover-
ed by Rouelle Junr., during his researches on urine, which were
published in the Journal de Medecine for 1773 and 1777. He
obtained it by evaporating recent urine to dryness and digesting
the residue in alcohol. The urea, which he distinguished by the
name of soapy matter, was dissolved. By proper evaporation it
was obtained in crystals. He mentions that it is difficult to ob-
tain it in a dry state, and that it absorbs moisture from the at-
mosphere. When heated, it yielded, he says, much more than
half its weight of carbonate of ammonia.* In 1808 a new set of
experiments was made upon it by Fourcroy and Vauquelin.f
* Macquer's Dictionnaire de Chimie (second edition), ii. 645.
t Ann. de Mus. d'Hist. Naturelle, ii. 226.
76 ANIMAL BASES.
They give a process for procuring it, and describe its properties
at considerable length, though they did not succeed in obtaining
it in a state of purity.
In the year 1798, Dr Rollo published his cases of Diabetes
Mellitus. To the second edition of this work was added an ap-
pendix by Mr Cruikshanks of Woolwich on Urine. In this
very important paper Mr Cruikshanks, who seems to have been
ignorant of what Rouelle had done, describes urea anew, and
gives a much more detailed account of its properties. Fourcroy
and Vauquelin take no notice of Cruikshanks in their paper,
and might have been supposed ignorant of the discoveries of the
British chemist, had not Fourcroy added copious notes to the
French translation of Hollo's work, and must therefore of neces-
sity have been acquainted with that book. In his Systeme de
connaisanqes Chimiques, published about the beginning of the
present century, he notices Cruikshanks's discoveries, and parti-
cularly the property which urea has of combining and crystal-
lizing with nitric acid ; but blames him for calling it animal ex-
tractive matter instead of distinguishing it by a peculiar name.
In the elaborate paper upon Urine by Fourcroy and Vauquelin,
published in 1800,* they notice Cruikshanks's discoveries; but
assure their readers that they had discovered urea and ascertain-
ed its characters, a whole year before they became acquainted
with Rollo's work, in consequence of the notice of it in the Bi-
bliotheque Britannique.
Neither Rouelle, Cruikshanks, nor Fourcroy and Vauquelin,
had obtained urea in a state of purity. But in 1 808 Berzelius
published the second volume of his Djurkemien in which he de-
scribes a process, rather complicated indeed, but successful, by
which he obtained it in a state of purity, and was enabled to deter-
mine its properties.! But, as this book was written in the Swe-
dish language, the discovery of Berzelius remained unknown till
his View of the Progress and present State of Animal Chemistry
was published in English in 1813.
In 1818, Dr Prout published his Observations on the Nature
of some of the Proximate principles of Urine.\ In this important
paper he gives a much easier and shorter process for obtaining
* Ann. de Chim. xxxi. 48, and xxxii. 80.
•f Forelasningar i Djurkemien, ii. 279.
\ In the eighth volume of the Medico- Chirurgical Transactions.
UREA. 77
pure urea than that of Berzelius, with which, indeed, he was un-
acquainted. He described the properties of pure urea and sub-
jected it to an accurate ultimate analysis. An analysis had been
previously made by Berard and another by Prevost and Dumas ;
both of which approached very near the results obtained by Prout,
except in the hydrogen, of which they obtained a great excess, be-
cause their urea had not been freed from water. More lately
Wohler made the curious discovery, that urea may be made ar-
tificially by uniting together cyanic acid and ammonia* He
described also the phenomena which take place when urea is ex-
posed to a high temperature, f He showed likewise thaf urea is
obtained when uric acid is distilled. } Berzelius, in the seventh
volume of the French translation of his Traite de Chimie, gives
a new process for obtaining urea. It seems merely a modifica-
tion of that of Prout.
The process of Dr Prout is the following : Evaporate by a
gentle heat a quantity of fresh urine to the consistence of a syrup.
Allow it to cool, and add by degrees pure concentrated nitric
acid till the whole assumes the form of a crystallized mass, hav-
ing a deep brown colour. Let this mass be washed with a little
cold water, and left to drain, then pour upon it slowly a pretty
concentrated solution of carbonate of potash or soda till it is com-
pletely neutralized. Concentrate the liquid by a cautious eva-
poration, and set it aside till the nitre formed is deposited in crys-
tals. Separate the liquid portion from these crystals, and add to
it enough of animal charcoal to reduce the whole to the state of
a thin paste. Let the mixture remain at least for some hours,
and then pour upon it a sufficient quantity of cold water to se-
parate the urea. Evaporate the colourless liquor to dryness by
a gentle heat and then boil the residue in very strong alcohol,
which will dissolve the urea, but leave the nitre and most other
saline substances behind it. By evaporating the alcoholic solu-
tions we obtain the urea in crystals, and two or three solutions in
alcohol and crystallizations are sufficient to bring it to a state
of purity.
The process of Berzelius is as follows : Evaporate the urine
to the consistency of a syrup, and then dry it over the steam-bath
* Poggendorf's Annalen, xii. 253.
f Jour, de Pharmacie, xvi. 298, or Poggendorf's Annalen, xv. 619.
\ Poggendorf, ibid. p. 529.
78 ANIMAL BASES.
as completely as possible. Treat the residue with absolute alco-
hol till every thing which that liquor is capable of taking up is
dissolved. Distil the alcoholic solution over the steam-bath.
Dissolve the residue in a little water, and digest it with a little
animal charcoal, which will render it nearly colourless. Filter
the liquid. Heat it to 122,° and dissolve in it as much oxalic
acid as it is capable of taking up at that temperature. On cool-
ing colourless crystals of oxalate of urea are deposited. By eva-
porating the residual liquid in a gentle heat we obtain more oxa-
late of urea. When it begins to thicken and has no longer a
strong acid taste, we may obtain a great deal more oxalate of
urea by heating it to 122°, and adding a new dose of oxalic acid.
Collect the whole crystals thus obtained and wash them with a
little cold water. Then dissolve them in boiling water, adding
a small quantity of animal charcoal, filtrate and evaporate. Oxa-
late of urea is deposited in crystals as white as snow. Dissolve
these crystals in water and mix it with carbonate of lime in very
fine powder, which decomposes the oxalate of urea with efferves-
cence. When the liquor no longer reddens litmus-paper, let it
be filtered to get rid of the oxalate of lime, and evaporate the
clear liquid over the water-bath. We obtain a white mass of a
saline appearance, which is urea, but still mixed with an alkaline
oxalate. This oxalate is removed by digesting the saline mass
in absolute alcohol. Nothing is dissolved but pure urea. What
remains is a chemical combination of urea and an alkaline oxa-
late, usually oxalate of ammonia.
Liebig has lately given another process, which he says is less
expensive, and which is merely the method used by Wohler to
convert cyanate of ammonia into urea.*
Twenty-eight parts of dry prussiate of potash are mixed with
14 parts of peroxide of manganese in powder, and the mixture
is made as intimate as possible. This mixture is heated on a
plate of iron over a charcoal fire to a dull red heat It takes
fire, but is gradually extinguished, and it must be well stirred
while cooling to prevent agglutination and to facilitate the admis-
sion of air. When cold it is digested repeatedly in cold water,
and the solution is mixed with 20^ parts of sulphate of ammo-
nia. The first concentrated liquid obtained by washing the pre-
cipitate should be set aside, and the sulphate of ammonia dis-
* Ann. der Pharm. xxxviii. 108.
UREA. 79
solved in the succeeding weak liquids. A copious precipitate of
sulphate of potash falls. The supernatant liquid is decanted oft*
and evaporated over the water-bath. More sulphate of potash
falls, which is separated, and this is repeated as long as the sul-
phate continues to form. The liquid is now evaporated to dry-
ness, and the solid residue is digested in boiling alcohol of 80 or
90 per cent. The urea is dissolved. It crystallizes as the al-
cohol cools or is evaporated. By this process a pound of prus-
siate of potash will furnish one-third of a pound of urea, colour-
less and crystallized.
The precipitate of potash when heated with black oxide of
manganese is converted into cyanate of potash, a salt very solu-
ble in water. When the solution of this salt is mixed with sul-
phate of ammonia, sulphate of potash and cyanate of ammonia
are formed, which last by a gentle heat, as Wohler first discover-
ed, is converted into urea.
Urea when pure and in crystals is white and transparent. It
has no smell, but a cooling taste, and its lustre is pearly. When
deposited from a concentrated hot solution it is in the form of
fine needles ; but by spontaneous evaporation it assumes the
form of long, narrow four-sided prisms. It is best obtained in
crystals by allowing a boiling-hot saturated alcoholic solution to
cool slowly. It produces no change on vegetable blues. It is
not affected by exposure to the air, unless the atmosphere be very
moist, when it deliquesces slightly, but is not decomposed. When
heated it melts, one portion is decomposed and another sublimed
without any apparent change. The specific gravity of its crys-
tals, as determined by Prout, is 1 '350.
At the temperature of 60°, water dissolves more than its own
weight of urea. The solution exposed to the air for some months
underwent no alteration. Boiling water dissolves any quantity
whatever of urea, and the urea is not altered at that temperature.
At the ordinary temperature alcohol of 0'816 dissolves the
fifth part of its weight of urea, and when boiling hot it dissolves
more than its weight of it. On cooling the additional quantity
is precipitated in crystals. It is hardly soluble in ether and oil
of turpentine, though it renders these liquids opaque.
The fixed alkalies and the alkaline earths decompose urea, es-
pecially when assisted by heat and when water is present. It
combines with most of the metallic oxides. Its combination with
80 ANIMAL BASES.
oxide of silver is grey. This compound detonates when heated
and the oxide is reduced. But urea does not seem capable of
decomposing any of the metallic salts. We can only combine it
with the oxides by double decomposition. The best way of ob-
taining these compounds is to mix a solution of a metallic salt
with a concentrated solution of urea, and to add as much alkali
as will saturate the acid of the metallic salt. We may combine
urea with oxide of lead by digesting the oxide in a concentrated
solution of urea.
Nitric acid forms with urea a compound which crystallizes in
large brilliant plates or transparent prisms ; though it is very
difficult to obtain the compound in regular crystals. These crys-
tals have an acid taste, and are not altered by exposure to the
air. At the temperature of 50° 100 parts of water dissolve 19-7
parts of nitrate of urea. This salt was found by Dr Prout's ana-
lysis to be composed of,
Nitric acid, . , 6-75
Urea, . . . *7-45
14-2
Wrhen heated in a retort it gives out a combustible gas,f and is
converted into nitrate of ammonia. When heated rapidly on
platinum foil it detonates. A good deal of cold is produced
when nitrate of urea is dissolved in water. When the aqueous
solution is boiled an effervescence takes place and carbonic acid
is disengaged. There remains a solution of carbonate and ni-
trate of ammonia.
Dr Prout discovered that oxalic acid forms a crystalline com-
pound with urea as well as nitric acid. Oxalate of urea is in
long slender plates. Its taste is cooling. When heated it melts
and boils, carbonate of ammonia is disengaged and cyanuric acid
is formed. Oxalate of urea dissolves in much greater quantity
in boiling than in cold water, and is deposited in crystals as the
* There is probably another compound of nitric acid and urea. I obtained a
•compound of nitric acid, 6-75 ; urea, 17-23, or rather more than twice the urea
stated in the text. In this case the urea was not deprived of its colouring mat-
ter, and therefore was heavier than it ought to have been. Had it been pure it
would in all likelihood not have exceeded fifteen, or double the quantity which
Prout obtained.
•j- Probably cyanogen.
UREA. 81
liquid cools. At 61° 100 parts of water dissolve only 4-37 of
oxalate of urea. It is still less soluble in alcohol than in water.
One hundred parts of alcohol of 0'833 dissolves only 1-6 of oxa-
late at the temperature of 61.° According to the analysis of Ber-
zelius this salt is composed of,
Oxalic acid, . • 37-436 or 4-5
Urea, . . . 62-564 or 7-525
100-000
It contains no water of crystallization. According to Berze-
lius this salt is capable of combining with the neutral alkaline
oxalates, forming double salts, which are soluble in alcohol. Lime
decomposes these salts in such a way that oxalate of lime preci-
pitates, while the urea and alkaline oxalate remain in solution.
When cyanuric acid is boiled with a concentrated solution of
urea, and the solution filtered while hot, fine needles are depo-
sited as the solution cools. These are composed of cyanuric
acid and urea. The same salt is obtained when uric acid is dis-
tilled in a retort. It is soluble in alcohol. Nitric acid decom-
poses it, nitrate of urea being formed, and cyanuric acid set at
liberty.
MM. Cap and Henri, by treating lactate of lime with oxalate
of urea, obtained lactate of urea, which crystallizes in white pris-
matic needles. They have extracted the same salt from urine.
They separated the free lactic acid from urine by an excess of
hydrate of zinc, and obtained lactate of urea identical with that
prepared by direct combination.* Urea possesses the property
of a base, and combines not only with nitric, oxalic, and lactic
acid, but also with sulphuric acid. Sulphate of urea may be ob-
tained by mixing 100 parts of oxalate of urea with 125 parts of
sulphate of lime in silky crystals, adding a little water and heat-
ing for an instant Add four or five volumes of alcohol, of spe-
cific gravity 0-843, filter and evaporate. The sulphate of urea
crystallizes in grains and needles ; its taste is sharp and cooling.
Whan common salt is dissolved in urine, it crystallizes in oc-
tahedrons, while sal-ammoniac, under the same circumstances,
crystallized in cubes. This alteration in the shape of the crystals
is ascribed to the salts entering into combination with urea.
* Phil. Mag. third series, xiii. 478; or Jour, de Pharm. xxv. 133.
F
ANIMAL BASES.
Urea is not precipitated from its solutions by any metallic salt
nor by tannin.
Urea was subjected to an ultimate analysis by Berard and by
Prevost and Dumas, but the proportion of hydrogen obtained by
these chemists was greatly in excess. It was analyzed by Dr
Prout in 1818,* with great precision. He obtained
Carbon, . 19-99
Hydrogen, . 6-66
Azote, . 46-66
Oxygen, . 26-66
100-
In Dobereiner's supplement it is stated that Wohler and Lie-
big made two analyses of urea with the following results :
Carbon, 20-02 20-20
Hydrogen, . 6-71 6-60
Azote, . 46-73 46-76
Oxygen, . 26-54 26-44
100-00 100-00
I do not know where these analyses were published. But it is
obvious at a glance that they coincide most satisfactorily with
the results previously obtained by Dr Prout.
Some idea of the atomic weight of urea may be formed from
the constitution of nitrate of urea and oxalate of urea. The
former gives 7*45, and the latter 7-52, the mean of which is
7-485. Now, if its atomic weight be 7*5, its constitution must
be
2 atoms carbon, . = 1-5 or per cent. 20*00
4 atoms hydrogen, . = 0'5 ... 6-66
2 atoms azote, . =3-5 ... 46-66
2 atoms oxygen, . =2-0 ... 26-66
7-5 100-
which corresponds exactly with the analysis of Dr Prout.
Wohler discovered that when a solution of sal-ammoniac is
poured upon cyanate of silver recently precipitated, chloride of
silver is formed, and instead of cyanate of ammonia, which ought
to be formed, if we evaporate the solution we get white crystals,
* Annals of Philosophy, first series, xi. 353.
ODORIN. 83
possessing the characters of urea. It is obvious that the consti-
tuents of urea and of cyanate of ammonia are identical.
Urea is . C2 H4 Az2 O2.
Cyanate of ammonia, C2 Az O -f H3 Az + H O.
At first cyanate of ammonia actually exists in the liquid.
But by the evaporation, the constituents of this salt arrange
themselves in a different manner, and constitute the more sta-
ble compound, urea. The difference between the properties of
cyanate of ammonia and urea is very great, yet the ultimate
constituents of both are the same. We see here strikingly ex-
emplified how entirely the properties of substances depend upon
the way in which the ultimate atoms are arranged.
Urea some years ago was introduced in France in medicine
as a diuretic. But I have never seen any well attested evidence
that it really possesses diuretic properties. Urea is not confined
to the urine. It has been detected in the blood and in the liquor
of dropsy.
CHAPTER II.
OF ODORIN.
WHEN animal substances are distilled, one of the constant
products is an empyreumatic oil, usually called DippeTs animal
oil, because that chemist was the first who obtained it in a state of
purity.* Unverdorben examined this oil in the year 1826,f and
extracted from it four different salifiable bases, which he distin-
guished by the name of odorin, animin, olanin, and ammolin.
Rectified Dippel's oil is composed of these four substances.
Odorin may be obtained from the rectified oil by the following
process : Saturate the ammonia in the oil till the alkaline reac-
tion is destroyed ; but care must be taken not to add more than
is sufficient for that purpose. Then distil the oil over the steam-
bath without adding any water to it. What comes over first is
* He made it known as a medicine in 1711, in a pamphlet, published at Ley-
den. All animal substances, he says, yield it. He purified it by 30 successive
rectifications.
f Poggendorf's Annalen, viii. 253.
84 ANIMAL BASES.
odorin. Examine what comes over from time to time, by letting
a drop of it fall into water. As long as it dissolves complete-
ly in the water, it is pure odorin, but as soon as it begins to ren-
der the water muddy, we may conclude that animin is coming
over also. We must then change the receiver that we may not
injure the purity of the odorin, which has already distilled over.
If we continue the distillation till only one-twentieth of the oil
remains in the retort, we obtain a mixture of odorin and animin.
The last 20th is a mixture of animin and olanin.
Odorin* is a colourless oil, which refracts light very power-
fully. It has a peculiar and disagreeable odour, differing from
that of Dippel's oil. Its taste is acrid and peculiar. It restores
the blue colour of litmus-paper reddened by an acid. It boils
at about 212°, and does not become solid though cooled down
to —13°.
It is very soluble in water, alcohol, ether, and the volatile
oils. It combines with the acids and forms salts. It dissolves
the resins, and the compounds formed with them are decomposed
when the solution is distilled with water. It combines also with
various extractive matters so intimately that it cannot be sepa-
rated from them by distillation. But these compounds are de-
composed by the more powerful salifiable bases.
All the salts of odorin have the form of oils ; and they have
little stability. A portion of the odorin makes its escape, and a
subsalt remains, or even the acid alone, if it is feeble and fixed.
The nitrate, muriate, and acetate of odorin may be distilled over
along with water. Odorin is separated from its combination
with acids by almost all the other bases. The few observations
made upon the salts of odorin by Unverdorben, the only person
who hitherto has examined them, are the following :
1. Sulphate of odorin. — When we mix concentrated sulphu-
ric acid with more odorin than it can saturate, the mixture be-
comes boiling hot. The sulphate precipitates under the form of
a heavier oil, through the excess of odorin, which does not dis-
solve it. This sulphate is very soluble in water. When we dis-
til or evaporate it a portion of the odorin escapes, and a super-
sulphate of odorin remains.
2, Sulphite of odorin is formed when odorin is made to ab-
sorb sulphurous acid gas. Heat is evolved, and an oily salt
* Unverdorben, Poggendorf's Annalen, xi. 61.
ODOKIN, 85
formed, which may be distilled over without alteration. It is
very soluble in water, and when exposed to the air absorbs oxy-
gen, and is converted into sulphate. Acids decompose it with the
evolution of sulphurous acid gas.
3. Nitrate of odorin may be distilled over ; but it undergoes
a partial alteration during the process. What comes over is
a mixture of nitrate and nitrite of odorin, together with an em-
pyreumatic oil. The residue in the retort, besides undecomposed
salt, consists of an extractive matter and a resin soluble in po-
tash.
4. Carbonate of odorin is a volatile oiL
5. Borate and benzoate of odorin when exposed to the air,
let go by far the greatest part of their base ; but retain a small
portion of it with considerable force.
6. Unverdorben did not succeed in his attempts to combine
odorin with arsenious acid.
7. Muriate of odorin may be formed by causing the base to
absorb the acid in the gaseous state. It is a colourless oil, which
does not become solid though cooled down to — 13°. It may be
distilled over without decomposition, and is very soluble in water.
When a current of chlorine is passed through odorin, decom-
position takes place, muriate of odorin is formed, but the great-
est part of the liquid is converted into a thick yellow magma.
About two-thirds of the odorin is converted into this matter,
while the remaining third becomes muriate. The yellow mag-
ma is partly soluble in potash, from which it is precipitated by acids
in the state of a yellowish-brown powder. The portion insoluble
in potash is a resinous-looking substance, fusible and soluble in
concentrated sulphuric acid.
Muriate of odorin has a brownish-yellow colour, and is solu-
ble in water, alcohol, and ether. When distilled odorin passes
over, and a supersalt remains in the retort.
8. When iodine is added to odorin, a powder is formed, hav-
ing a brown colour, and insoluble. There is formed at the same
time an extractive-looking substance, soluble in ether, and pre-
cipitated by the salts of lead and silver.
9. The double salts of odorin have more fixity and a stronger
resemblance to the common class of salts than the simple salts.
Sulphate of copper is dissolved by odorin, and the solution
has an intense blue colour. A subsalt of sulphate of copper re-
86 ANIMAL BASES.
mains, showing that sulphate of odorin and copper has been
formed. By evaporation we obtain it of a green colour ; and
the excess of odorin may be gradually driven off.
Acetate of copper behaves with odorin in the same way as
sulphate. When we mix an aqueous solution of this salt with
odorin, no precipitate falls, and when the mixture is left to spon-
taneous evaporation, in proportion as the excess of odorin is vo-
latilized, a double subsalt is deposited in four-sided short prisms,
having a grass green colour. This salt does not lose its odorin
though exposed to the air. It is soluble in water and alcohol,
but insoluble in ether. When distilled, odorin comes over first,
then acetate of odorin, and there remains in the retort acetate
of copper, mixed with brown subacetate, which has precipitated.
Neither oxide of copper nor carbonate of copper is soluble in
odorin.
When a solution of corrosive sublimate is mixed with muriate
of odorin, the two salts combine together, and when we evapo-
rate the liquid, an oil precipitates limpid-like water. This oil is
a double salt not altered by exposure to the air. When we mix
a solution of corrosive sublimate with a solution of odorin, a
subsalt precipitates in the form of a crystalline powder, which is
soluble in ten times its weight of boiling water, and which is
mostly deposited in crystals as the solution cools. If we boil the
solution, the odorin escapes with the steam, and nothing remains
but the corrosive sublimate. The anhydrous salt behaves in the
same way. It is soluble in alcohol and ether, and is slowly de-
composed when exposed to the air.
When chloride of gold is mixed with muriate of odorin, a
double salt precipitates in small yellow crystals, soluble in twen-
ty times their weight of boiling water. . The solution of this salt
reddens litmus-paper. It is more soluble in alcohol than in
water, and is insoluble in ether. It may be fused, but in that
case is easily decomposed into muriate of odorin, chlorine, and
metallic gold ; dilute acids dissolve it at a boiling temperature,
and it is again deposited unaltered as the liquid cools.
When odorin is mixed with chloride of gold, a yellow saline
powder precipitates, which is a double subsalt almost insoluble
in cold water, slightly soluble in boiling water, but again preci-
pitated as the solution cools. It is not altered by exposure to
the air, and may be fused without undergoing decomposition.
ANIMIN. 87
After cooling, it is yellow and transparent. When exposed to
a stronger heat, muriate of odorin may be distilled over, leaving
metallic gold with some other products of decomposition in the
retort. Nitric acid scarcely dissolves it even at a boiling heat.
Chloride of platinum gives with muriate of odorin a double
salt, which crystallizes, has a yellow colour, and is soluble in four
times its weight of water. With odorin alone it forms a subsalt,
which is very little soluble, and which precipitates under the form
of a powder. Boiling water dissolves a small quantity of it,
which is deposited as the solution cools. The action of these
two double salts upon reagents is similar to that of the two cor-
responding salts of gold.
CHAPTER III.
OF ANIMIN.
IT was stated in the last chapter, that when rectified oil of Dip-
pel, saturated with ammonia, was subjected to distillation, the
first liquid which came over was pure odorin. As soon as the
liquid which distils begins to render water muddy, a new re-
ceiver is applied, and the distillation continued, till only one-
twentieth of the original quantity remains in the receiver. The
liquor thus obtained is a mixture of odorin and animin. If we
agitate it with a little water, the odorin will be dissolved, together
with a little animin. We may extract the odorin from this solu-
tion by supersaturating the liquid with sulphuric acid, evaporat-
ing the solution, and distilling the residue with a base. The
animin remains under the form of an oil. It has a peculiar
smell. It is soluble in twenty times its weight of cold water,
but it is much less soluble in hot water. Hence it happens that
the cold solution becomes milky when heated, and resumes its
limpidity again when allowed to cool. The solution changes
reddened litmus-paper to a violet blue colour. It is very solu-
ble in alcohol, ether, and oils.
Its affinity for acids seems nearly the same as that of odorin.
Its salts resemble oils like those of odorin ; but they are much
less soluble in water.
1, Sulphate of animin is an oily body very little soluble in
88 ANIMAL BASES.
water. When we boil it with water, a portion of the animin is
volatilized, and there remains a supersalt very soluble in water
and alcohol, and which undergoes no farther change, though the
boiling be prolonged.
2. Benzoate of animin is little soluble in cold water, but more
soluble in hot water, by which it is not so easily decomposed as
benzoate of odorin.
3. Muriate of Animin forms double salts with the chlorides of
copper, gold, and platinum. The double chloride of animin and
mercury has the form of a colourless oil, that of chloride of ani-
min and gold the form of a brown oil, while the chloride of ani-
min and platinum crystallizes. All these double salts are very
little soluble in water.*
CHAPTER IV.
OF OLANIN. t
IT has been already stated, in the preceding chapters, that
when rectified Dippel's oil is distilled to one-twentieth part, what
passes over is odorin and animin. The twentieth that remains is
chiefly olanin ; though it still retains a portion of animin. If we
agitate this residue four times successively with five times its
weight of water, the animin will be dissolved by that liquid, and
the olanin will remain in a state of purity.
It is an oily liquid, somewhat thick, and resembling a fat oil.
It has a peculiar but not a disagreeable odour, and reacts very
feebly as an alkali upon reddened litmus-paper. When expos-
ed to the air it becomes brown, and is gradually converted into
fuscin. It is but little soluble in water, but very soluble in al-
cohol and ether.
Its salts are all oily ; and, according to Unverdorben, they re-
semble the salts of odorin very closely in their properties. But
they have been very imperfectly examined. The following are
the facts stated by Unverdorben, and I am not aware that they
have been examined by any other chemist.
* Unverdorben, Poggendorf's Annalen, xi. 67.
f The name is derived from the first syllables of ofeum animale, adding to them
the termination in.
3
OLANIN. 89
1. When Per chloride of Iron is mixed with muriate of ola-
nin, a double oily salt is formed, having a deep brown colour so-
luble in twice its weight of cold water ; but requiring four times
its weight of hot water to dissolve it. Hence when a saturated
cold solution is raised to the boiling temperature, a great deal of
the salt is separated, which is again redissolved as the solution
cools. This double salt is neither decomposed by boiling nor by
acids. It dissolves in oil of cumin, and water can only take it
from that solution by long boiling, and in proportion as the oil
evaporates.
2. Corrosive sublimate and 'muriate of olanin form an oily co-
lourless double salt. Olanin combines with corrosive sublimate
into a subsalt, little soluble in water, and having a yellow colour.
It is fusible, and resembles a resin. It requires a thousand times
its weight of boiling water to dissolve it, and from this solution
it is deposited in a crystalline form. It is not decomposed by
boiling, and is insoluble in alcohol.
3. Chloride of gold forms with muriate of olanin a neutral
double salt, having a deep-brown colour. It is little soluble in
cold, but more soluble in hot water, and is very soluble in alco-
hol and ether. When this salt is long boiled with water, a little
of the gold is reduced to the metallic state.
Chloride of gold and olanin form a subsalt resembling a re-
sin. It is hard, brown, insoluble in water, but soluble in alco-
hol. If we pour muriatic acid into that solution, the salt be-
comes neutral. But this scarcely happens unless alcohol be pre-
sent.
4. With chloride of platinum, olanin forms a double neutral
salt, which has the appearance of tar. It is more soluble in wa-
ter than the chloride of gold and olanin. It is also very soluble
in alcohol, but insoluble in ether.*
* Unverdorben, Poggendorf's Annalen, xi. 70.
90 ANIMAL BASES.
CHAPTER V.
OF AMMOLIN. *
THIS substance, like the three preceding, was first obtained
and examined by Unverdorben. His process for obtaining it is
the folio wing :v
Pour dilute sulphuric acid into unrectified Dippel's oil, as long
as any effervescence is produced. When this is at an end, add
as much more sulphuric acid as has been already mixed with the
oil; allow the mixture to remain for some hours, agitating it
frequently during that time. When the sulphuric acid liquor
and the oil have separated from each other, draw off the oil and
wash it with water. Add these washings to the sulphuric acid
liquor. This acid solution contains supersulphates of odorin,
animin, olanin, and also of ammolin, saturated with empyreuma-
tic oil dissolved. To get rid of this last oil, let the liquor be
boiled for three hours in an open vessel, replacing the water as
it evaporates. By this treatment, a portion of the oil is vola-
tilized, and another portion separates under the form of a brown
resin. Mix the liquor, which has now become brown, with a
fortieth part of its weight of nitric acid, and evaporate till only a
fourth part of the original quantity remains. Add water till the
original bulk of the liquid is restored, and after having nearly,
but not fully, saturated it with carbonate of soda, distil till what
comes over has neither the smell of odorin nor animin. What
remains in the retort is a mixture of sulphate of ammonia and
sulphate of ammolin. After taking this residue out of the re-
tort, let the sulphuric acid be completely saturated with carbon-
ate of soda, and then evaporate the liquid. Carbonate of ammo-
nia is disengaged, and a brown oil separates. This oil is to be
cautiously distilled. What passes over is ammolin, containing
an empyreumatic oil, having the smell of horse-radish. What
remains in the retort isfuscin.
Boil what has been distilled over with water. A portion of
the empyreumatic oil is volatilized, and another portion dissolves
in the water. The ammolin which remains is a colourless oily
body, which is heavier than water, and which instantly restores
the colour of litmus-paper reddened by an acid.
* The word is made-up of the first syllables of the words awwoniacum and
o/eum, adding the termination in.
FUSCIN. 91
It is so little volatile that when boiled with wate very little
of it, if any, is volatilized. It dissolves in forty times* its weight
of boiling water, and 200 times its weight of cold water.
If we evaporate the solution, the water may be driven off, leav-
ing the ammolin behind. Ammolin is very soluble in alcohol and
ether.
Chlorine decomposes it ; the products are muriate of ammolin,
animin, fuscin, and an extractive-looking matter. Ammolin
combines readily with extractive matter and resins. It is more
strongly alkaline than any of the three preceding bases When
boiled with ammoniacal salts, it expels the ammonia, doubtless
in consequence of its little volatility. When even a great
excess of ammonia is added to an ammolin salt, very little of the
ammolin is disengaged.
The ammolin salts are oily, very soluble in water and alcohol ;
but insoluble in ether. Sulphate and nitrate of ammolin are
probably decomposed when distilled, free ammolin coming over,
mixed with the products of decomposition. Acetate and mu-
riate of ammolin may be distilled over almost completely, with-
out being decomposed. With succinic and benzoic acids am-
molin forms oily salts, which may be heated without undergoing
decomposition.*
CHAPTER VI.
OF FUSCIN. t
To Unverdorben we are indebted also for the discovery of fus-
cin, which he extracted from unrectified Dippel's oil by the fol-
lowing process :
One part of the oil is mixed with one-eighth of hydrate of
potash dissolved in six parts of water. This mixture is cautiously
distilled till the volatile substances and the empyreumatic oil
pass into the receiver, and there remains in the retort solution
of potash united to pyrozoic acid, on which swims a viscid pitchy
substance. It is this last substance which contains the fuscin.
When it is digested in acetic acid a portion is dissolved. This
portion is precipitated by the alkalies. The precipitate is brown.
* Unverdorben, Poggendorf's Annalen, xi. 74.
| The name derived from,/«sci/s, Irown.
92 ANIMAL BASES.
Digest it in absolute alcohol, a portion is dissolved. This por-
tion is fuscin. When the alcohol is evaporated, we obtain the
fuscin in a brown coloured mass, cracked in all its dimensions.
Fuscin is solid, has a brown colour, and is insoluble in water.
The acids dissolve it, and when the solutions are evaporated a
brown matter remains, which is soluble in water and in aqueous
alcohol ; and which, while in a solid state, may be exposed to
the atmosphere without undergoing any alterations. The com-
pounds of fuscin with succinic and benzoic acids constitute an ex-
ception to this solubility in water ; for they are insoluble in that
liquid. When any of the solution of salts of fuscin is mixed with
potash, fuscin precipitates, which, when washed and dried, has
the form of a brown powder. It does not melt when heated, but
is charred, and gives out a smell similar to that of burning horn.
Fuscin, whether in the state of a dry powder, or in solution,
in acids gradually absorbs oxygen from the atmosphere, and as-
sumes a red colour. The solutions in that case contain the same
substance which alcohol leaves undissolved when digested on
the brown matter precipitated by alkalies from the acetic acid
solutions mentioned in the process for procuring fuscin. This
substance, as well as fuscin, combines with the acids. But it soon
loses this property, and assumes the form of a brown powder,
insoluble in all menstrua. *
CHAPTER VII.
OF CRYSTALLIN. t
THIS substance was obtained by Unverdorben from indigo ;
but its analogy to the five preceding bases is so strong, that it was
deemed better to place it here than among the products of vege-
table substances.
When indigo is distilled per se it gives first water and oil,
and then oil holding resin in solution passes over. The oil
is colourless and volatile, and has not an empyreumatic smell,
but one similar to that of indigo when strongly heated. This
oil, when left exposed to the air, becomes yellow, and then con-
* Unverdorben, Poggendorfs Annalen, viii. 261.
t So called because its salts are capable of crystallizing, which is not the case
with those of any of the preceding five bases.
APOSEPEDIN. 93
tains ammonia, crystallin, and several other substances. The
crystallin may he obtained by the following process : —
Mix the oil with sulphuric acid, which dissolves it, leaving the
other substances behind. Mix the acid liquid with another base,
and distil. The crystallin passes over.
Crystallin is a colourless oil, which is heavier than water. Its
odour is strong, and has some resemblance to that of new honey.
It does not react sensibly as an alkali. It is but little soluble in
water, yet it may be distilled over with that liquid. When ex-
posed to the air it becomes red, and then communicates a yellow
colour to water when dissolved in it.
Sulphate of crystallin crystallizes, whether it be neutral or con-
tain an excess of acid. When the neutral salt is evaporated, it
is converted into a supersalt. It is insoluble in absolute alco-
hol. Its aqueous solution becomes gradually brown, and then it
contains sulphate of fuscin. When supersulphate of crystallin is
heated, it melts and concretes on cooling into a crystalline mass.
When exposed to a stronger heat it undergoes decomposition, and
there are formed sulphate of crystallin, sulphate of odorin, and a
great quantity of sulphate of ammonia. The charcoal remaining
leaves no residue when burnt.
Phosphate of crystallin crystallizes readily, when it is neutral ;
but the superphosphate does not crystallize at all. Alcohol se-
parates the crystals by removing the excess of acid and the water.*
CHAPTER VIII.
OF APOSEPEDIN. t
THIS substance was first noticed by M. Proust in 1818, J who
gave it the name of cheesy oxide. It was again examined, and
its properties ascertained by Braconnot in 1827, § who distin-
guished it by the name of aposepedin, because it is formed when
casein undergoes a species of putrefaction.
Cheese, as every body knows, consists essentially of coagulat-
ed casein, || from which the great quantity of liquid which it ori-
* Unverdorben, Poggendorfs Annalen, viii. 397.
f From. dLTtot and o-Hirtfeev, putridity.
$ Ann. de Chim. et de Phys. x. 40. § Ibid., xxxvi. 161.
H This substance will be described in a subsequent chapter of this volume.
94 ANIMAL BASES.
ginally contained has been expelled by pressure. When thus
treated it may be kept a considerable time, during which it is
slowly undergoing an alteration, which renders it more agree-
able to the taste. If the liquid portion has not been squeezed out
with care, it undergoes a species of putrefaction, similar to what
takes place when moist gluten of wheat is left in a similar state.
Proust conceived that during this process a peculiar acid was
formed, which he distinguished by the name of caseic acid, toge-
ther with another substance which he called caseous or cheesy
oxide. Braconnot showed that the caseic acid of Proust was com-
posed of a congeries of substances which he separated from each
other. The cheesy oxide he found a peculiar substance, and dis-
tinguished it, as has been already stated, by the name of apose-
pedin.
He mixed 4167 grains of fresh cheese from creamed milk
with 61 cubic inches of water, and left the mixture to putrefy for
a month in a temperature varying from 68° to 77°. During this
interval the greatest part of the cheese was dissolved. The so-
lution was separated by filtrations from the undissolved portions.
Its smell was putrid, but no odour of sulphur could be distin-
guished in it. When evaporated to the consistence of honey it
gradually congealed into a granular mass, one portion of which
dissolved in alcohol, while another portion remained unattached
by that liquid. The first of these portions was the caseate of am-
monia of Proust, and the second his caseous oxide.
This last substance was dissolved in water and the solution
treated with animal charcoal, which rendered it colourless. This
liquid being left to spontaneous evaporation, deposited brilliant
crystalline vegetations, constituting rings and cauliflower-looking
concretions on the edges of the liquid. To obtain it perfectly
white it was necessary to dissolve and evaporate it two or three
times successively. Thus purified its properties were as follows :
Its colour is white ; it has no smell, its taste slightly bitter"
with a flavour of roasted meat It crackles under the teeth ; it
is heavier than water, and is easily reduced to powder. It burns
away without leaving any residue. When heated in a tube of
glass open at both ends a portion of it is volatilized unaltered,
under the form of long slender crystals. Every time that this
process is repeated a new portion is decomposed. When dis-
tilled per se in a retort it does not sublime but undergoes decom-
position. A solid oil passes over into the receiver together with
TAURIN. 95
a liquid holding carbonate and sulphohydrate of ammonia in so-
lution.
When aposepedin is heated on polished silver, the metal is
blackened, being converted into sulphuret. At the temperature
of 57° aposepedin is soluble in%2 times its weight of water. The
solution speedily putrefies, and acquires a very disagreeable smell.
Aposepedin is very soluble in alcohol. When a boiling alco-
holic solution cools, the oxide is precipitated under the form of
a fine light powder, which after being dried, has a good deal of
resemblance to magnesia. Nitric acid converts it into a bitter
matter and a yellow oil ; but no oxalic acid is formed. Muria-
tic acid dissolves a greater quantity of it than water, and when
the solution is concentrated it concretes into a mass on cooling.
The aqueous solution of aposepedin is neither precipitated by
alum nor persulphate of iron. The infusion of nut-galls throws
it down abundantly in flocks, which are redissolved by adding a
great excess of the reagent. When mixed with a solution of su-
gar no fermentation is produced.
The portion of the cheese dissolved in ammonia owes its acid
properties to acetate of ammonia, generated during the putrefac-
tion of the cheese. It contained also a brown extractive matter,
ammonia-phosphate of soda and a brown oil, heavier than water,
and having an acrid and burning taste. Braconnot considered
it as a compound of oleic acid with an acrid oil.
CHAPTER IX.
OF TAURIN.
THIS substance was discovered by L. Gmelin in 1824, during
the researches of Tiedemann and Gmelin on ox bile ; and its pro-
perties were described by him in 1827.* They distinguished it
by the name of gallenasparagin, which L. Gmelin afterwards
changed into taurin, obviously from the Latin name of the ani-
mal from whose bile it was extracted. There can be little doubt
that it was formed from the choleic acid of bile by the processes
to which Gmelin subjected ox bile ; though he was of opinion
that it constituted one of the many ingredients of which he con-
* Poggendorf's Annalen, viii. 326.
96 ANIMAL BASES,
sidered the bile to be composed. Gmelin's method of obtaining
it was the following :
Ox bile was mixed with muriatic acid, and filtered to separate
a mucous or albuminous matter which had precipitated ; the filter-
ed liquor being left for some dd^ in repose, some stearic acid
was deposited. The filtered liquor was then concentrated by eva-
poration till only a small quantity remained. This residue con-
sisted of a resinous matter and an acid liquor. The liquor being
separated from the resin and still farther concentrated, more of
the resin fell, and finally crystals of taurin and of common salt
were deposited. The taurin was picked out and purified by a
second crystallization. When the resin is dissolved in absolute
alcohol and the solution filtered, taurin in small crystals remains
on the filter. It may be purified by washing it in absolute alco-
hol, dissolving it in water and crystallizing.
Thus purified taurin consists of transparent colourless crystals.
The primitive form is a right rhombic prism with angles of 111°
44', and 68° 16'. But it is usually in six or eight-sided prisms,
terminated by four or six-sided pyramids. These crystals crackle
under the teeth, and have a sharp taste, neither sweetish nor sa-
line. Taurin neither reacts as an acid nor an alkali, and is not
altered by exposure to the air, even when heated to 212.°
When strongly heated taurin melts into a thick liquid, becomes
brown, swells, and exhales an agreeable but empyreumatic odour,
similar to that of burning indigo. It leaves a charcoal which is
easily consumed. When distilled per se it gives a thick brown
oil with a little yellow coloured and acidulous water, which con-
tains an ammoniacal salt in solution, and reddens a solution of
perchloride of iron.
Taurin dissolves in 15 J times its weight of water at the tem-
perature of 54.° It is much more soluble in boiling water, and
the surplus crystallizes as the solution cools. Boiling alcohol of
0*835 dissolves only ji^th part of its weight of taurin, and in ab-
solute alcohol it is almost insoluble.
Concentrated sulphuric acid dissolves it without the assistance
of heat, forming a transparent brown liquor from which the tau-
rin is not precipitated by water. When this solution is raised
to the boiling point its colour becomes darker, but no sulphurous
acid is disengaged. Cold nitric acid dissolves taurin readily, and
when the acid is evaporated away the taurin remains unaltered.
The aqueous solution of taurin is not sensibly acted on by
muriatic acid, potash, ammonia, alum, chloride of tin, chloride
CHITIN AMMONIA. 97
of iron, sulphate of copper, corrosive sublimate, nitrate of mer-
cury, or by nitrate of silver.
Taurin, according to the analysis of M. Dema^ay, is com-
posed of C4 H7 Az O10. This may be resolved into,
2 atoms oxalic acid, C4 O6
1 atom ammonia, . H3 Az
4 atoms water, . . O4 H4
C4 H7AzO10= 15-625
This composition has been confirmed by the analysis of Dumas
and Pelouse.*
CHAPTER X.
OF CHITIN.
THIS name (from %/7<wi>, tunica) has been given by Dr Odier
to the hard horny crust which forms the outer covering of many
insects, and in particular the elytra of the coleopterous insects.!
When these elytra are boiled in a solution of caustic potash, the
menstruum extracts albumen, a matter analogous to the extract
of meat, and a fatty coloured matter which is soluble in the al-
kali ; but insoluble in alcohol and water. What remains is chitin.
Chitin is white and translucent. It does not melt when heat-
ed ; but is charred without giving out ammonia or hydrocyanic
acid. It is soluble in dilute sulphuric acid, and in nitric acid
when assisted by heat. The solution in nitric acid is not yellow,
CHAPTER XL
OF AMMONIA.
AMMONIA is beyond question the most important of all the anU
mal bases. But its use is so indispensable to the chemist at the
very commencement of his investigations, that it it was necessary to
describe its properties while treating of the Chemistry of Inor-.
ganic Bodies. (Vol. i. p. 138.)
• Ann. der Pharm xxvii. 292.
f Odier, Mem. de Mus. d'Hist, Nat. i. 35.
98 AMMONIA.
It enters into a greater number of combinations tban perhaps
any other base whatever. I propose in this section to give
merely a catalogue of the most important of these compounds,
and, at the same time, to explain the views at present entertained
respecting their nature.
Ammonia has been long known to be a compound of azote
and hydrogen. But azote and hydrogen are at present con-
ceived to be capable of uniting in three different proportions.
1. The first, called amide, is a compound of one atom azote,
and two atoms hydrogen, Az H2 — 2. It is considered as the
radical of ammonia, and has not hitherto been obtained in an
isolated form. It is not a base ; but is capable of combining
with bases, and seven of such compounds are known.
2. The second compound of azote and hydrogen is ammonia.
It consists of one atom of azote combined with three atoms am- *
monia, Az H3 = 2-125. It is a powerful base, and readily com-
bines with and neutralizes acids.
3. The third compound of azote and hydrogen is called am-
monium. It is a compound of one atom of azote with four atoms
hydrogen, Az H4 = 2-25. It possesses the character of a metal,
and is capable of combining with metals. Hitherto it has not
been obtained in an isolated state. But all the ammoniacal salts
containing oxygen acids are considered at present as compounds
of the acid and oxide of ammonium.
Let us take a view of the compounds which these three modi-
fications of ammonia are capable of forming.
I. AMIDES.
1. Amide of potassium, . Az H2 -f- K r= 7
2. Amide of sodium . Az H2 -f Na = 5
3. Amide of mercury, . Az H2 + Hg — 14-5
White precipitate, Az H2 Hg -f Chi. Hg = 31-5 (Kane) ob-
tained by precipitating corrosive sublimate by caustic ammonia.
When white precipitate is treated with caustic potash, we ob-
tain a yellow powder composed of Az H2 Hg + 2 Hg O -f
Chl. Hg = 58-5 (Kane.)
A number of other complex compounds have been analysed by
Dr Kane of Dublin.
4. Amide of copper and hyposulphate of ammonium, Az H2
Cu + (S2 O5) (Az H4 O) = 18-25.
AMMONIA. 99
5. Amide of copper and nitrate of ammonium, Az H2 Cu -f
(Az O5) + (Az H4 O) = 16.
And so of the other compounds of metallic amides with salts
of ammonium.
1. Oxamide, C2 O2 + Az H2 = 5-5.
This was the substance originally discovered by Dumas, which
led to the whole doctrine of amides. It is oxalate of ammonia
— an atom of water
2. Sulphamide, Az H2 + SO2 = 6.
Discovered by Regnault Obtained by mixing chlorine gas,
sulphurous acid gas and olefiant gas. A liquid is formed which, by
a current of ammoniacal gas, is converted into a white powder
and sal-ammoniac. The white powder is sulphamide.
3. Sulphohydramide, SO3 + Az H4 = 7-25.
The anhydrous sulphate of ammonia of Rose.
4. Bisulphohydramide, 2 (S O2) + Az H4 = 10-25.
The anhydrous acid sulphite of ammonia discovered by Rose.
ii. AMMONIA, Az H3 = 2-125.
1. Liquid ammonia, Az H3 -f 3 Aq.
It dissolves oxides of zinc, copper, nickel, cobalt, &c.
2. Ammoniated oxide of copper, 2 (Az H3) -f- 3 (Ca O) -f- 6
Aq — 26 (Kane.)
A blue powder.
3. Ammoniated oxide of mercury, Az H3 -f 3 (Hg O) -f 3
Aq — 46 (Kane.)
And so of the other ammoniated oxides.
1. Ammonietted chloride of sulphur, Az H3 4- S Chi = 8-625
and 2 (Az H3) + S Chi = 10-75.
2. Ammonietted sesquichloride of phosphorus, 5 (Az H3) -f
(Ph Chl4) = 21-375.
3. Ammonietted perchloride of phosphorus, 5 (Az H3) -f Ph
Chi2* =• 23-875.
4. Ammonietted chloride of boron, 3 ( Az H3) + 2 (Bo Chi1*)
= 15-125.
5. Ammonietted perchloride of tin, Az H3 + 2 (St Chi2) =
18-375.
6. Ammonietted chloride of calcium, 4(AzH3)+Ca Chl=15*5.
7. Ammonietted chloride of strontium, 4 (Az H3) -f Str Chi
= 18-5.
100 AMMONIUM.
8. Ammonietted chloride of copper, 3 (Az H3) -f- Cu Chi =
14-875.
9. Ammonietted chloride of nickel, 3 (Az H3) + N Chi =
14-125.
10. Ammonietted chloride of cobalt, 2 (Az H3) + Cb Chi = 12.
11. Ammonietted chloride of lead, 3 (Az H3) + 4 (Pb Chi) =
76-375.
12. Ammonietted chloride of antimony, Az H3 -j- Sb Chi3* =
21-375.
13. Ammonietted chloride of mercury, Az H3 + 2 (Hg Chi)
= 36-125.
14. Ammonietted dichloride of mercury, Az H3 + 2 (Hg2 Chi)
= 61-125.
15. Ammonietted chloride of silver, 3 (Az H3) + 2 (Ag Chi)
- 42-375.
16. Ammonietted chloride of platinum, Az H3 -j- PI Chi —
18-625.
Ammonia combines also with bromides, iodides, and fluorides.
It combines also with sulphates of magnesia, zinc, copper, nickel,
cobalt, cadmium, silver, and with nitrate of silver ; though the
exact proportions have not been determined.
in. AMMONIUM, Az H4 —
Amalgam of ammonium, Hg -f Az H4 = 14-75.
1. Sal-ammoniac, or chloride of ammonium, Chi -f Az H4 =
6-75.
2. Chloride of ammonium and magnesium, (Chi -f- Az H4) 4-
Mg Chi = 12-75.
3. Chloride of ammonium and zinc, 2 (Chi -f- Az H4) -{- 2
(Zn Chi) + Aq = 31-875, (Kane.)
There is another compound constituting a pearly powder, which
contains also oxide of zinc, according to the analysis of Kane.
4. Chloride of ammonium and nickel, (Chi -f Az H4) -f- (Az
H3 + N O) -|- Aq z* 14-25.
5. Chloride of ammonium and copper, (Chi -f- Az H4) -f- Ga
Chi -f Aq = 16-375.
6. Chloride of ammonium and mercury, (Chi + Az H4) -f
Hg Chi + Aq = 24-875.
7. Chloride of ammonium and platinum, (Chi + Az H4) +
PI Chi = 23-25.
8. Bromide of ammonium, Az H4 -f Br = 12-25.
AMMONIUM. 101
9. Iodide of ammonium, Az H4 + I = 17-875.
Iodide of ammonium and gold, (I -f- Az H4) -f Au I3 =
77-626.
10. Fluoride of ammonium, Az H4 -f Fl = 4-5.
11. Seleniet of ammonium, Az H4 + Se = 7-25.
12. Sulphuret of ammonium, Az H4 S = 4-25.
13. Bisulphuret of ammonium, Az H4 S2 =, 6-25.
14. Persulphuret of ammonium, Az H4 S5 — 12-25.
Sulphohydrate of ammonium, Az H4 S + HS — 6-375.
Bisulphocarburet of ammonium, Az H4 S + CS2 = 9.
15. Oxide of ammonium, Az H4 O = 3-25.
16. Sulphate of ammonium, SO3 -f Az H4 O + Aq = 9-375.
17. Bisulphate of ammonium, 2 (SO3) + Az H4 O = 13-25.
18. Ammonium-sulphate of magnesia, (SO3 -f Az H4 O) -f
(SO3 + Mg O) + 7 Aq = 23-625.
19. Ammoniacal alum, (SO3 + Az H4 O) + 3 (SO3 + Al O)
-f 24 Aq = 54.
And so with the double ammoniacal salts described in the
Chemistry of Inorganic Bodies, (Vol. ii. p. 750.) Adding an
atom of water to convert ammonia into oxide of ammonium.
1. Nitrate of ammonium, Az O5 4 Az H4 O = 10.
And so with the double ammoniacal nitrates.
2. Chlorate of ammonium, Chi O5 + Az H4 O = 12-75.
3. lodate of ammonium, IO5 + Az H4 O = 24.
4. Carbonate of ammonium, CO2 + Az H4 O = 6. This salt
exists only in solution.
And so with the double ammoniacal carbonates.
5. Phosphate of ammonium, 2 (PO2*) + Az H4 O + 2 (HO)
+ Aq = 15-625, and 2 (PO2*) -f 2 (Az H4 O) -f- H O
= 16-625.
6. Soda-phosphate of ammonium, 2 (PO2*) -f
CNa O ^
-J Az H4 O V
(HO j
+ 8 Aq = 26-375.
And so with the other double ammoniacal phosphates.
7. Chromate of ammonium, Chr O3 -f Az H4 O -j- Aq
= 10-875.
8. Permanganate of ammonium, Mn O7 + Az H4 O -f- Aq
= 14-875.
9. Tungstate of ammonium, Tu O3 -f Az H4 O + Aq
= 19-875.
102 ANIMAL OXIDES WITH AZOTE NOT OILY.
10. Molybdate of ammonium, Ml O3 + Az H4 O = 12-25.
11. Vanadiate of ammonium, VO3 -f Az H4 O — 14-75.
12. Selenite of ammonium, Se O2 + Az H4 O =r 10-25.
For farther information respecting the compounds of ammonia,
we refer the reader to the Memoir of M. Bineau in the Annal.
de Chim. et de Phys. Ixvii. 225 ; and Ibid. Ixx. 251.
CLASS III.
INTERMEDIATE ANIMAL OXIDES.
THE animal principles belonging to this class have been so im-
perfectly examined, that the characters of many of them are only
inferred from very imperfect analogies. We shall divide them
into five sets.
1. Oxides containing azote and not oily.
2. Oxides not containing azote and not oily.
3. Oily oxides saponifiable.
4. Oily oxides not saponifiable.
5. Colouring matters.
It can scarcely be doubted that the oily saponifiable oxides
contain an acid ; and it is probable that the animal colouring
matters resemble the vegetable in their nature.
CHAPTER I.
OF ANIMAL OXIDES CONTAINING AZOTE AND NOT OILY.
THESE bodies have been all recently discovered, and most of
them have been formed artificially by treating uric acid with va-
rious reagents. They are eight in number ; namely,
1. Xanthic or uric oxide.
2. Cystin.
3. Allantoin.
4. Alloxane or erythric acid.
5. Alloxantine.
k
6. Uramile.
7. Murexide.
8. Murexane.
XANTHIC OR URIC OXIDE. 103
SECTION I. OF XANTHIC OR URIC OXIDE.
Dr Marcet gave the name of xanthic oxide to the constituent
portion of a small calculus, which Dr Babington having receiv-
ed from one of his patients gave to Marcet for examination. Its
texture was compact, hard, and laminated. The surface was
smooth, and it had a reddish cinnamon colour, which was much
heightened by adding caustic alkali to the calculus in powder.
Before the blow-pipe, it crackled, split in pieces, became black,
and was ultimately consumed, leaving only a minute particle of
wliite ash. The smell which it emitted was that of an animal
substance, and was peculiar, though feeble and not easily defined.
When exposed to destructive distillation, it crackled, split into
scaly fragments, blackened, and emitted a fetid ammoniacal li-
quor, from which carbonate of ammonia crystallized, leaving a
heavy yellowish oil.
When reduced to an impalpable powder, the greatest part of
it dissolved in boiling water, and the solution reddened litmus pa-
per. When the liquid was allowed to cool, it became covered
with a white flocculent film, which gradually subsided and con-
stituted a white crust.
Caustic potash dissolved this calculus very readily, and the so-
lution was precipitated by acetic acid, provided the acid was not
added in great excess. The mineral acids also dissolved it, though
not nearly so readily as the alkalies. Concentrated sulphuric
acid did not blacken it
When the solution of the calculus in nitric acid was evaporat-
ed to dryness, the residue assumed a bright lemon colour. This
yellow residue was partly soluble in water, to which it commu-
nicated its colour. The addition of an acid destroyed the yel-
low colour, but caustic potash turned it red, and upon evapora-
tion, it assumed a brilliant crimson hue. This colour disappear-
ed on adding water, the yellow tint being reproduced, while the
liquid remained transparent. The previous action of nitric acid
is necessary for these changes of colour : for if potash be added
to the pure xanthie oxide, no change of colour takes place.
Xanthic oxide is insoluble in alcohol and ether, very sparing-
ly soluble in acetic, and not at all in oxalic acid. It is insoluble
in bicarbonate of potash and bicarbonate of ammonia.*
Such are the properties of this uncommon substance as deter-
* Marcel's Essay on Calculous Disorders, p. 96.
104 ANIMAL OXIDES WITH AZOTE NOT OILY.
mined by Dr Marcet. In the year 1816, a similar calculus was
extracted from a patient by Langenbeck, and given to Stromeyer,
who determined it to be the same as the xanthic oxide of Marcet.
A considerable portion of this calculus is still in Langenbeck's
collection. It weighs eleven grammes, or almost 170 grains.
It is much larger than the one described by Marcet. It has been
lately examined and analyzed by Wohler and Liebig, *
The surface of the calculus was partly light brown, smooth, and
shining, partly earthy and whitish. The fracture had a brownish
flesh-colour. It was composed of concentric layers, separable
from each other, and had a nucleus composed of the same mat-
ter with the rest of the calculus. It had the same degree of hard-
ness as the uric acid calculi. When rubbed or scraped, it as-
sumed a waxy lustre.
As it might be supposed to contain more or fewer of the con-
stituents of urine, Wohler and Liebig purified the xanthic oxide, or
uric oxide, as they have called it, in the following way : — The cal-
culus was pulverized and dissolved in caustic potash. The solu-
tion had a dark brownish yellow colour, with a shade of green,
not unlike the colour of bile. Through this solution pure car-
bonic acid gas was passed till the potash was converted into bi-
carbonate. The uric oxide precipitated in the form of a white
powder. When this powder was washed and dried, it assumed
the form of masses of a light yellow, which, when rubbed, acquir-
ed a waxy lustre. It contained no trace of potash, differing in
this respect from uric acid. For when an alkaline solution of
this last is saturated with carbonic acid gas, the precipitate is not
pure uric acid, but urate of potash.
Uric oxide is soluble in sulphuric acid, and the solution has a
yellow colour. The oxide is not precipitated by water. In this
respect also it differs from uric acid. It is insoluble in muriatic
and oxalic acid ; a circumstance which distinguishes it from cystic
oxide.
When subjected to destructive distillation it so far resembles
uric acid, that a great deal of hydrocyanic acid is evolved. But
the empyreuma has a different smell, similar to that of distilled
horn. There is given out also a sublimate of carbonate of am-
monia, but no urea.
When heated with oxide of copper the azotic was to the car-
* Ami. der Pharm. xxvi. 340,
CYSTIN* 105
bonic acid gas as 1:2-5. The result of an analysis of this sub-
stance in Liebig's laboratory gave its composition
Carbon, . 39*28 or 5 atoms — 3-75 or per cent. 39-48
Hydrogen, . 2-95 or 2 atoms = 0-25 ... 2-63
Azote, . 36-35 or 2 atoms — 3-5 ... 36.84
Oxygen, . 21-42 or 2 atoms — 2- ... 21-05
100.00* 9-5 100-
So that its formula is C5 H2 Az2 O2 = 9-5. We have seen be-
fore that the formula for uric acid is C10 H4 Az4 O6. Now the
half of this is C5 H2 Az2 O3. So that uric oxide differs from
uric acid by containing one atom less oxygen. It may probably
be at least occasionally an ingredient in urine ; though it is so
very seldom deposited in a solid form.
SECTION IT. — OF CYSTIN.
This name has been applied to the substances constituting the
whole, or almost the whole of the calculus first observed and de-
scribed by Dr Wollaston, and called by him cystic oxide, f This
calculus Dr Wollaston had obtained about the year 1805 from
Dr Reeve of Norwich. It had been taken from his brother, when
he was five years old, and at that time was covered by a coating
of phosphate of lime very loose in its texture, and consequently
very soon separated; Dr Wollaston only met with one other
calculus of the same kind. It was in the collection of calculi in
Guy's Hospital, and was No. 46 of that collection. It was ex-
tracted by the usual operation from William Small, a man of
36 years of age. Dr Henry of Manchester afterwards found
two calculi in his collection belonging to the same species ; and
Dr Marcet detected cystic oxide calculus in no fewer than three
different cases, of which he has given a description.^ Some years
ago I was kindly presented with another calculus belonging to
the same species by Dr Apjohn, which had been extracted by the
usual operation in Dublin. M. Lassaigne, in 1823, announced
that fie had found the same substance in a calculus from a dog.§
* There must be a typographical error in the data from which this composi-
tion was deduced. For when we calculate from them the result differs enor-
mously from the statement in the text, deduced by Liebig from his analysis.
f Phil. Trans. 1810, p. 223.
$ On the Chemical History and Medical Treatment of Calculom Disorders^
p. 28.
§ Ann. de Chim. et de Phys. xxiii. 328.
106 ANIMAL OXIDES WITH AZOTE NOT OILY.
But his analysis differs so much from that of cystic oxide by Dr
Prout, that I consider it impossible that both operated upon the
same substances. Two cystic oxide calculi exist also in the Muse-
um of St Bartholomew, and have been described by Mr Taylor.*
One of them weighed 740 grains. It is, therefore, the largest
calculus of this species hitherto observed. It was analyzed by
Mr Taylor, and found composed of,
Cystic oxide, . . 91
Phosphate of lime, . . 3-8
Ammonia-phosphate of magnesia, . 1-0
Animal matter, . . . 4-2
100-0
About the year 1836, M. O. Henrie got two very small calculi
of the same species, which had been passed with great pain by
an individual 50 years of age. f
Cystic oxide calculi have a pale yellow colour, are translucent,
and appear irregularly crystallized. They are not composed of
distinct laminae, but constitute one compact mass. They have
also a peculiar glistening lustre, like that of a body having a
high refractive density.
When cystic oxide is submitted to destructive distillation, it
yields foetid carbonate of ammonia, partly fluid, and partly in a
solid state, a heavy foetid oil, and there remains a black spongy
coal, much smaller in proportion than is found after the distilla-
tion of uric acid calculi.
Under the blowpipe it may be distinguished by the smell, which
at no period resembles that of hydrocyanic acid ; but, in addition
to the usual smell of burnt animal substances, there is a peculiar
fcetor quite different from that of any other substance.
Cystic oxide is not soluble in water, alcohol, acetic acid, tar-
taric acid, citric acid, nor in bicarbonate of ammonia. It is dis-
solved in considerable quantity by muriatic, nitric, sulphuric,
phosphoric, and oxalic acids. It is also dissolved readily by pure
alkaline menstrua, by potash, soda, ammonia, and lime-water.
Even bicarbonates of potash and soda dissolve it
The combination of cystic oxide with acids may be made to
crystallize without difficulty, and they form slender spiculae ra-
diating from a centre, which readily dissolve again in water, un-
* Phil. Mag, (3d series) xii. 237. f Jour, de Pharm., xxiii. 71.
ALLANTOIN. 107
less they have been injured by having been in any degree over-
heated. The muriatic salt is decomposed at 2 12°, in consequence
of the volatility of its acid, and the rest are easily destroyed by
a greater excess of heat.
The salt formed by combination with nitric acid does not
yield oxalic acid, and does not become red when similarly treat-
ed with uric acid ; but assumes a brown colour, becoming gra-
dually darker till it is ultimately black.
When the combinations with alkalies are evaporated they leave
small granular crystals. The only definite form observed was
that of flat hexagonal plates. But the primary shape of the crys-
tal could not be ascertained. On the cystic oxide calculus in
Guy's Hospital minute crystals nearly cubical were observed ; but
whether these were crystals of cystic oxide was not determined.
Dr Prout subjected cystic oxide to an ultimate analysis, and
obtained,
Carbon, 2 9 '8 7 5 or 6 atoms = 4'5 or per cent.
Hydrogen, 5*125 or 6 atoms =0.75
Azote, . 11*85 or 1 atom = 1*75
Oxygen, 53*150 or 8 atoms — 8*00
100*00 15* 100*
These numbers merely express the smallest ratios of the number
of atoms of each constituent which cystin contains. For no ex-
periments have been made to determine its atomic weight. The
analogy of uric oxide and urea would lead us to double the num-
ber of atoms of each constituent, and to represent the constitu-
tion of cystin by the following formula, C12 H12 Az2 O16 = 30.
SECTION III. — OF ALLANTOIN.
This substance was first detected by Vauquelin and Buniva in
the liquor of the amnios of the cow, and was called by them am-
niotic acid* It was afterwards found that the liquor from which
it was extracted was not that contained in the amnios but in the
allantois. This induced chemists to change its name to allantoic
acid; and Wohlerand Liebig having found it incapable of neu-
tralizing alkaline bases changed that name to allantoin.
An account has been given in the Chemistry of Vegetable
Bodies, (p. 212) of the method employed by Wohler and Liebig
* Ann. de Chim. xxxiii. 279.
108 ANIMAL OXIDES WITH AZOTE NOT OILY.
to form allantoin artificially. But it will be requisite in this
place to be somewhat more particular.
Pure uric acid extracted from the excrements of serpents was
mixed with water* to the consistence of a thin pap. This mix-
ture was raised to the boiling point, and peroxide of lead in fine
powder was added by little and little. A reaction took place,
carbonic acid was given out with effervescence. The pap thick-
ened considerably unless water was added ; and the peroxide of
lead disappeared. More and more of this peroxide was cautious-
ly added, taking care to renew the water and to keep the whole
in a boiling heat till the mixture, by assuming a chocolate colour,
indicated that a slight excess of peroxide had been added. The
whole was then filtered while hot, and the matter on the filter was
repeatedly washed with boiling water.
The filtered liquid was colourless, and on cooling deposited a
great number of hard brilliant crystals, which were colourless, or
had only a very slight tint of yellow. These crystals constitute
allantoin. The mother water by evaporation yields an addition-
al quantity of them.
The liquid, after depositing the allantoin, having been evapo-
rated to the consistence of a syrup over the water-bath, yielded
on cooling long prismatic crystals of urea. The white matter
collected on the filter is oxalate of lead. If we wash it, mix it
with water, and pass through it a current of sulphuretted hydro-
gen, the oxalic acid freed from lead dissolves in the water, and
may be obtained in crystals.
Thus the products of the reaction of uric acid and peroxide of
lead are allantoin, urea, oxalic acid, carbonic acid, and protoxide
of lead, and these are the only products.
Wohler and Liebig compared the allantoin thus obtained with
a quantity of allantoin from the liquor of the allantois of a calf
which they had in their possession, and found the two to agree in
their characters and composition.
The crystals are colourless and transparent Their primitive
form is a rhomboid. They are hard and their faces are very
brilliant. They are tasteless and do not alter the colour of lit-
mus-paper. At 68° allantoin is soluble in 160 times its weight of
water. But it is much more soluble in hot water, and crystal-
lizes while the solution is cooling. It does not combine with the
* Ann. de Chim. et de Phys Ixviii. 228.
ALLANTOIX. 109
bases into salts, and therefore is not entitled to be considered as
an acid. The oxide of silver makes the only exception to this.
Allan toin forms with it a compound, which is a white powder.
It may be obtained by mixing aqueous solutions of nitrate of sil-
ver and allantoin together, and adding ammonia drop by drop as
long as a precipitate continues to fall. The dilute acids decom-
pose this compound, disengaging the allantoin.
At a high temperature it is decomposed by the caustic alka-
lies into ammonia and oxalic acid. This decomposition is most
easily observed when we employ barytes. If we dissolve allan-
toin in boiling hot barytes water, ammonia is disengaged and a
white powder falls, which is oxalate of barytes. When allantoin
is heated with sulphuric acid exactly the same decomposition
takes place ; only instead of oxalic acid, carbonic acid and car-
bonic oxide are disengaged, and the ammonia combines with the
acid.
Allantoin being subjected to an ultimate analysis in Liebig's
laboratory, was found composed of,
Carbon, . 30-20 or 4 atoms = 3-000 or per cent. 30-38
Hydrogen, 4-04 or 3 atoms = 0-375 ... 3-80
Azote, . 35-27 or 2 atoms — 3-500 ... 35-44
Oxygen, . 30-49 or 3 atoms = 3-000 ... 30-38
100-00 9-875 100-
We might consider it as a compound of,
2 atoms cyanogen, . C4 Az2
3 atoms water, . . H3 O3
To convert it into oxalate of ammonia, or C2 O3 +Az H3, we
must add three atoms water. We have then,
Allantoin, . C4 H3 Az2 O3
3 atoms water, . H3 O2-^ i~ 3
C4 H6 Az2 O6. Now two atoms
oxalate of ammonia, C4 O6 + Az2 H6
The compound of allantoin and oxide of silver being analyzed
in Liebig's laboratory, was found composed of,
Allantoin, . 56-45 or 18-79
Oxide of silver, 43-55 or 44-5
100-
110 ANIMAL OXIDES WITH AZOTE NOT OILY.
If it consist of 2 atoms allantoin united with one atom oxide of
silver, then an atom of allantoin will weigh 9 '4, which approaches
the number 9*875, resulting from Liebig's formula.
The constitution of allantoin, urea, and oxalic acid being
known, it is easy to see what happens when uric acid and per-
oxide of lead are made to act upon each other.
1 atom uric acid is, . C10 Az4 H4 O6
Subtract 1 atom urea, C2 Az2 H4 O2
Remains, . . C8 Az2 O4
Add O2 from peroxide of lead, O2
C8 Az2 O6
Now C8 Az2 O6 are resolvable
into 2 atoms oxalic acid, C4 O6
2 atoms cyanogen, . C4 Az2
C8 Az2 O6
Now we have seen already that if three atoms water be added
to 2 atoms cyanogen, we have an atom of allantoin or C4 Az2
H303.
Thus we see that 1 atom of uric acid -f- 2 atoms oxygen -f
3 atoms water, form
1 atom urea, . C2 H4 Az2 O2
2 atoms oxalic acid, . C4 O6
1 atom allantoin, . C4 H3 Az2 O*
C10H7 Az40n
Which is the same as
1 atom uric acid, a C10H4 Az4 O6
2 atoms oxygen, i-~ O2
2 atoms water, . H3 O3
C10H7 Az4 O11
The carbonic acid evolved is obviously owing to the action of
the peroxide of lead on the oxalic acid.
Liebig conceives that the reason why the atomic weight of al-
lantoin in the allantoate of silver is less than that deduced from
analysis, is that two atoms of allantoin, when they unite with
oxide of silver, lose an atom of water, so that they become C8
Az4 H5 O5.
ALLOXANE OR ERYTHRTC ACID. Ill
SECTION IV. — OF ALLOXANE OR ERYTHRIC ACID.
This remarkable substance was discovered in 1819 by Dr Gas-
pard Brugnatelli ;* but succeeding experimenters were unable to
succeed in forming it till it was discovered again in 1838 by
Wohler and Liebig, who gave a minute detail of the process
which they followed.f
The substances formed by the action of nitric acid on uric acid
vary with the strength of the nitric acid and the temperature.
Alloxane is the compound obtained when the nitric acid is con-
centrated. If we put into cold nitric acid of the specific gravity
1 -425 dry uric acid, a strong effervescence takes place, a good
deal of carbonic acid is disengaged together with some nitrous
acid, and when the gases cease to be evolved, the liquid assumes
the state of a thick bouillee consisting of small prismatic crystals.
The mother water contains ammonia. A gentle heat determines
the evolution of pure azotic gas. The mass contains nothing
but ammonia, and the small crystals, which consist of pure al-
loxane.
If in this experiment we employ a great excess of nitric acid,
and if we boil it with the crystals, on allowing the matter to cool,
long straight prismatic crystals are formed, having a very strong
resemblance to oxalic acid.
If we employ nitric acid of the specific gravity 1'55, alloxane
is still formed ; but a portion of the uric acid undergoes other
modifications. Small masses of it become brown or black as if
charred, and the colouring matter which is developed is not easily
removed from the crystals.
Wohler and Liebig employed the following process for pre-
paring alloxane. The most concentrated fuming nitric acid is
mixed with the ordinary acid of commerce so as to form a liquid
having a specific gravity from 1 45 to 1 '5. This mixture is put
into a very shallow porcelain evaporating basin, and then is ad-
ded to it by little and little at a time half its weight of dry uric
acid ; every portion added being mixed very carefully with the
nitric acid. On every addition an effervescence takes place, and
care must be taken to wait till the effervescence is over, and
the liquid cold, before any more of the uric acid be added.
By this process we obtain a mass almost solid, consisting of
brilliant and transparent crystals. It is poured upon a very
* Ann, de Chim. et de Phys. viii. 201, | Ibid. Ixviii. 240.
ANIMAL OXIDES WITH AZOTE NOT OILY.
porous brick or upon bloating-paper. In twenty-four hours the
liquid portion is removed, and there remains a dry white powder,
easily purified by repeated crystallizations. It is mixed with its
own weight of water in a porcelain capsule, and heated till com-
plete solution takes place. The solution being filtered and left
in a warm place, colourless transparent crystals, having the dia-
mond lustre and considerable bulk, are gradually deposited.
These crystals constitute alloxane in a state of purity.
Alloxane crystallizes in water under different forms. On al-
lowing a hot saturated solution to cool, very bulky crystals are
formed, very deliquescent, and containing a great deal of water
of crystallization. The crystals deposited in a hot solution are
always anhydrous, and do not effloresce. The form of the crystal
is a right prism with a rectangular base, and its primary form is
a rhomboid. They have a pearly lustre, especially after having
been kept for some time, and may be easily obtained an inch in
length. The anhydrous crystals have the form of pyroxen ; the
primitive form being an oblique prism with a rhomboidal base.
The crystals have usually the form of rhomboidal octahedrons
truncated on the angles. They have a vitreous lustre, are trans-
parent and much smaller than the hydrous crystals.
Alloxane is soluble in alcohol, and very soluble in water. Its
solution communicates a red stain to the skin, and a peculiar
disagreeable smell. It reddens litmus-paper ; but loses that
property when a base is present, although it does not form a salt.
Its solution does not decompose the carbonates of lime or barytes.
Oxide of lead may be boiled with it, without oocasioning any al-
teration. From these facts, it is obviously not entitled to the
name of acid.
After the addition of an excess of barytes water, the liquid so-
lution of alloxane remains for some time clear and colourless,
but after some hours, it deposites white brilliant crystals, which
are soluble in hot water, and again deposited when the solution
cools. An excess of lime-water occasions an immediate white
crystalline precipitate, soluble in a great quantity of water.
When alloxane is mixed with the salts of protoxide of iron, it
occasions at first no precipitate ; but the liquid assumes an intense
indigo blue colour.
Alloxane, heated with sulphuric acid and metallic copper, does
not give out a trace of oxide of azote or of nitrous acid. When
ALLOXANE OR ERYTHRIC ACID. 113
a solution of alloxane is gently heated with peroxide of lead,
pure carbonic acid gas is given out. After the process is over,
we obtain a white magma of carbonate of lead, containing merely
a trace of oxalate. The filtered liquor does not contain any
lead; but when evaporated, yields crystals of urea, mixed with a
very minute quantity of a white powder. Thus by the action of
peroxide of lead, alloxane is decomposed into carbonic acid and
urea.
Alloxane was analyzed with much care in Liebig's laboratory.
The atoms of carbon were to those of azote as 4 : 1. The mean
of five analyses made with oxide of copper gave,
Carbon, 30-22 or 8 atoms =6 or per cent 30
Hydrogen, 2*54 or 4 atoms — 0-5 ... 2-5
Azote, 17-63 or 2 atoms = 3-5 ... 17-5
Oxygen, 49-61 or 10 atoms = 10-0 ... 50-0
100-00 20-0 100.
The theoretic constitution, or C8 H4 Az2 O10, corresponds very
well with the analysis.
When the crystals of hydrated alloxane are heated, the water
which they contain is disengaged, and they are converted into
small crystals of anhydrous alloxane. This, as is well-known,
is the case when sulphate of zinc is heated. The hydrated crys-
tals effloresce very quickly in a hot place or in a vacuum, be-
come opaque and white, and fall into powder. When de-
prived of their water by heat, they diminish in weight about 26-3
per cent. — hence they are composed of,
1 atom alloxane, 20 or 74*76
6 atoms water, 6-75 or 25-24
100.
When alloxane is heated, the crystals assume a slight shade
of red.
The composition of alloxane being known, it is easy to explain
its formation by the action of nitric acid on uric acid.
It has been already stated that uric acid may be considered
as a compound of an unknown acid and urea.
1 atom of urea is . C2 H4 Az2 O2
1 atom of the acid, C8 Az2 O4
H
114 ANIMAL OXIDES WITH AZOTE NOT OILY.
The urea is disengaged, and there remains the
acid, Cz8 Az2 O4
Add 2 atoms oxygen, . . O2
4 atoms water, . H4 O4
we have C8 H4 Az2 O10
which is an atom of alloxane.
The urea, as is well known, and the nitrous acid formed mu-
tually, decompose each other into nitrite of ammonia, and free
cyanic acid. The nitrite of ammonia, by a gentle heat, is de-
composed into azotic gas and water ; while the cyanic acid, along
with the elements of water, is decomposed into ammonia and
carbonic acid. Equal volumes of these two gases ought to be
disengaged, while the proportion of ammonia formed by the de-
composition of the cyanic acid ought to remain in the liquid.
Now, as all this is what actually takes place, there can be no
doubt of the accuracy of the explanation of the action of nitric
acid on uric acid given by Wohler and Liebig.
When crystals of anhydrous alloxane are dissolved in concen-
trated muratic acid by the assistance of heat, we perceive an ef-
fervescence which continues till the action is complete. The pro-
ducts differ according to the mode of proceeding. If we only
heat the solution for a few minutes it becomes muddy, and de-
posites on cooling a great number of brilliant and transparent
crystals of alloxantin. The solution being freed from these crys-
tals, and purified from muriatic acid by evaporation, gives crys-
tals of oxalate of ammonia. The decomposition consists in the
separation of two atoms of alloxane into oxalic acfd, oxaluric
acid, and alloxantin.
1 atom oxalic acid, = C2 O3
2 atoms alloxane
= C16H8 Az4CP
1 atom oxaluric acid, = O6 H3 Az2 O7
1 atom alloxantin, = C8 H5 Az2 O10
C16 H8 Az4 O20
The oxaluric acid, by boiling with muriatic acid, is decompos-
ed into cyanate of ammonia, the acid of which, in presence of the
same agent, becomes bicarbonate of ammonia.
Alloxane treated in the same way with dilute sulphuric acid
gives the same products. This is a very convenient and rapid
way of obtaining alloxantin.
By a long continued boiling, the alloxantin disappears in its
ALLOXANTIN. 115
turn, and a new yellow powder, scarcely soluble in water, is de-
posited. The same substance is often obtained when we trans-
form alloxane into alloxantine by zinc and muriatic acid, when
we employ too concentrated a solution, or continue the heat too
long.
It is then deposited under the form of a yellow crust, which
may be purified by washing. It dissolves readily in ammonia,
and brilliant, yellow, granular crystals are soon deposited. When
heated with excess of ammonia they are transformed into a yel-
lowish jelly, very little soluble in water and ammonia.
Wohler and Liebig dissolved in ammonia the yellow crystals
obtained by the action of zinc and muriatic acid on alloxane, and
neutralized the liquid by acetic acid. The yellow substance se-
parated in a few days. The analysis of it led to the formula CG
H3Az203=: 11-375.
When a concentrated solution of pure alloxane is boiled, car-
bonic acid is given out for a long time. It then gives with
barytes a deep blue precipitate, and with carbonate of ammonia
a rich crystallization of murexide. On cooling, and even dur-
ing the boiling, a great quantity of alloxantin falls down, though
none originally existed in the liquid. 3 atoms of alloxane gave,
2 atoms alloxantin, . C16 H10 Az4 O10
1 atom parabanic acid, . C6 H2 Az2 O6
2 atoms carbonic acid, . C2 O4
3 atoms of alloxane . C24 H12 Az6 O20 *
SECTION V. OF ALLOXANTIN.
The solution of uric acid in dilute nitric acid takes place with
the same phenomena as in concentrated acid. But after a gentle
evaporation the liquid deposites hard transparent crystals, which
are colourless, or have a slight yellow tinge. These crystals have
been distinguished by Wohler and Liebig by the name of allox-
antin. f
Alloxantin is scarcely soluble in cold water. It dissolves,
though slowly, in boiling water, but is almost wholly deposited in
crystals as the solution cools. Even after five or six successive
crystallizations it reddens litmus- paper ; yet it wants the charac-
* Ann. der Pharm. xxxviii. 357.
f Ann. de Chim. et de Pliys. Ixviii. 227.
116 ANIMAL OXIDES WITH AZOTE NOT OILY.
ters of an acid ; for when it comes in contact with a base it is
immediately decomposed.
When barytes water is added to a solution of alloxantin, a
copious precipitate of a fine violet colour falls, which becomes
white, and then disappears entirely when the liquor is boiled. An
excess of barytes throws down a fine white precipitate. The reac-
tion of alloxantin with nitrate of silver is very remarkable. As soon
as the two liquids come in contact, a black precipitate of metal-
lic silver falls, though no gas whatever is evolved, nor any thing
else thrown down. When the liquid is separated from the me-
tallic silver by filtration, barytes water throws down a white pre-
cipitate from it. With selenious acid it acts in the same way, a
red precipitate of selenium falling.
When alloxantin is placed in an atmosphere containing gase-
ous ammonia, it assumes a red colour, its crystals become opaque,
and lose no weight though exposed to a temperature of 212°.
At a higher temperature they lose water.
Alloxantin was subjected to an ultimate analysis in Liebig's
laboratory. The mean of four different analyses gave
Carbon, . 30-06 or 8 atoms = 6-0 or per cent 29-82
Hydrogen, . 3*16 or 5 atoms = 0.625 ... 3-10
Azote, . . 17-53 or 2 atoms =3-5 ... 17-40
Oxygen, . . 49-25 or 10 atoms == 10-0 ... 49-68
100-00 20-125 100-
This gave the formula C8 H5 Az2 O10 = 20-125. So that al-
loxantin differs from alloxane by containing an additional atom
of hydrogen.
When alloxantin is formed in dilute nitric acid, one atom of
oxygen only instead of two unites to the elements of the acid, C8
Az2 O4, which, united to urea, constitutes uric acid. Hence the
nitric is converted into nitrous acid (Az O4.) This acid, by the
contact of water, is decomposed into hyponitrous acid (Az O3),
and nitric acid ( Az O5) ; only one of these decomposes the urea.
The consequence is, that a quantity of urea remains undecom-
posed in the liquid. Accordingly, if we add nitric acid, crystals
of nitrate of urea are deposited.
When alloxane is treated by deoxygenizing bodies, it is con-
verted into alloxantin. Thus, if we pass a current of sulphuret-
ted hydrogen gas through a moderately concentrated solution of
ALLOXANTIN. 117
alloxane, the liquid becomes muddy, and a precipitate of pure sul-
phur falls. Soon after a white crystalline powder is deposited,
and if the solution of alloxane was concentrated, the liquor as-
sumes the form of a thick magma of crystals of alloxantin. When
the precipitate is treated with boiling water it dissolves, with the
exception of the sulphur, and deposites a large quantity of allox-
antin in white transparent crystals.
We convert alloxane into alloxantin also by adding to its solu-
tion a little muriatic acid, and then introducing a piece of zina
After an interval of some hours a considerable deposite of allox-
antin makes its appearance under the form of a crystalline crust.
Protochloride of tin likewise throws down alloxantin from a
solution of alloxane.
On the other hand, when alloxantin is treated by oxygenizing
bodies, it is converted into alloxane. If we add a few drops of nitric
acid to a solution of it, a slight effervescence is observed, and the
products of the decomposition of that acid are given out. When
the liquid is evaporated to the consistence of a syrup it congeals
into a crystalline mass, which, being dissolved in water, the
solution, when evaporated, spontaneously deposites colourless
crystals of alloxane.
Alloxantin does not produce anything else than alloxane : no
ammonia nor any other substance is evolved.
When ammonia is added to a hot solution of alloxantin it be-
comes purple ; but the colour disappears by the action of heat,
and also sometime after the hot solution is allowed to cool. When
ammonia is added to alloxane, scarcely a sensible change of co-
lour takes place. When we add nitric acid to alloxantin, drop
by drop, we observe, when we saturate a portion of it from time
to time with ammonia, and heat it a little, that the solution ac-
quires a more and more intense purple colour. After the addi-
tion of a certain quantity of nitric acid, and afterwards of am-
monia, the purple colour becomes so deep that the liquid loses
its transparency. But if more than a certain proportion of ni-
tric acid be added, this property disappears.
A solution of uric acid in dilute nitric acid treated immediate-
ly by ammonia does not acquire a purple colour, or at least
speedily loses it again. The same solution subjected during some
minutes to boiling, or even gentle heat, takes with ammonia a
deep purple colour, and gives a considerable quantity of the
118 ANIMAL OXIDES WITH AZOTE NOT OILY.
beautiful cantharides green crystals constituting the purpurate of
ammonia of Prout. But we do not obtain them, if we conti-
nue the heat beyond a certain time; the solution even loses
the property of becoming coloured with ammonia. The reason
of these phenomena is obvious : the solution of alloxantin treat-
ed with a certain quantity of nitric acid and ammonia furnishes
the green crystals. But when all the alloxantin is converted
into alloxane by the action of the nitric acid, these crystals cease
to make their appearance.
Nitrate of silver converts alloxantin into alloxane, by giving
out an atom of oxygen, which forms water with the additional
atom of hydrogen, while the silver is precipitated in the metal-
lic state.
SECTION VI. OF URAMILE.
Pure uramile* is obtained by boiling for some minutes a mix-
ture of thionuric acid or thionurate of ammonia, and dilute sul-
phuric or muriatic acid. The solution, even though dilute, con-
cretes at that temperature into a white magma consisting of very
minute brilliant needles. This magma is easily washed, and di-
minishes enormously in volume when dried.
Uramile may be prepared exceedingly beautiful by dissolving
thionurate of ammonia in cold water, heating the solution to the
boiling point, adding the requisite quantity of muriatic acid,
keeping the mixture boiling for a few minutes, and then allowing
it to cool. In this case the uramile is formed slowly, and crys-
tallizes in long brilliant hard needles, having a feathery form.
Dr Gregory of Aberdeen has given the following process for
preparing uramile : Dissolve thionurate of ammonia in boiling
water, add a small excess of dilute sulphuric acid, and boil for a
short time. Even while hot uramile is deposited in large quan-
tity. It is to be collected and dried by pressure.
Dry uramile is white, has a satiny lustre, is insoluble in cold
water ; but slightly soluble in boiling water, from which it sepa-
rates as the liquid cools. It dissolves in ammonia and is thrown
down unaltered by the addition of acids to the solution. When
boiled with ammonia it is decomposed ; the liquid becomes yel-
lowish, and acquires the property of assuming a deep purple co-
lour and of depositing green crystalline needles. Uramile con-
* Ann. de Chim et de Phys. Ixviii. 261.
MUREXIDE. 1 19
tains no sulphuric acid. By nitric acid it is decomposed with ef-
fervescence. When the solution is evaporated and saturated
with ammonia, it assumes a purple colour like the solution of
uric acid in nitric acid.
Uramile is soluble in potash ley and in sulphuric acid. It is
precipitated unaltered from the former by acids, and from the
latter by water.
When heated with oxide of copper the carbonic acid and azo-
tic gases evolved were to each other as 8 : 3. When dried by
artificial heat it assumes a slight shade of red. The mean of four
analyses in Liebig's laboratory, by means of oxide of copper, gave
the constituents of uramile as follows :
Carbon, . 32-83 or 8 atoms = 6 or per cent 33-56
Hydrogen, 3-75 or 5 atoms = 0-625 ... 3-50
Azote, . 28-72 or 3 atoms = 5-250 ... 29-38
Oxygen,. 34-70 or 6 atoms = 6-000 ... 33-56
100-00 17-875 100-00
Thus it appears, that, at a boiling temperature, thionuric acid
is decomposed into one atom of uramile and two atoms of sul-
phuric acid.
1 atom thionuric acid is, . C8 H5 Az3 O12 S2
1 atom uramile, . C8 H5 Az3 O6
Remain O6 S2
which is equivalent to two atoms of sulphuric acid.
SECTION VII. OF MUREXIDE. *
This is the substance which Dr Prout first obtained by adding
ammonia to a solution of uric acid in nitric acid, and which he
described under the name ofpurpurate of ammonia. The pre-
paration of it was so uncertain, and depended upon so many
circumstances which had not been determined, that scarcely any
chemist was able to succeed in obtaining it till the subject was
investigated by Wohler and Liebig.
Dr Prout found that this substance dissolves in the alkalies
while ammonia is evolved, and that the acids precipitate from its
solution a white or yellow matter in fine brilliant plates. This
1 ast substance he called purpuric acid.
* Ann. de Chim. et de Phys. Ixviii. 314,
120 ANIMAL OXIDES WITH AZOTE NOT OILY.
The subsequent experiments of Vauquelin* and Lassaigne,f
show only that these chemists conceived that there existed in pur-
purate of ammonia another substance, besides those pointed out
by Prout, but which they did not obtain or characterize by any-
positive results.
Murexide was obtained by Wohler and Liebig in the following
manner : One part of uric acid was put into a porcelain capsule
and moistened with thirty-two times its weight of water. The
mixture was raised to the boiling point, and nitric acid of speci-
fic gravity 1*425 previously mixed with twice its weight of water
was added by small quantities at a time, waiting till the effer-
vescence was at an end before a new quantity was added. The
addition of nitric acid was stopped when only a trace of uric acid
remained. The liquid was raised to the boiling point, filtered
and evaporated by a gentle heat. During this evaporation a
slight effervescence was continually observed. The liquid when
concentrated to a certain point became coloured. The evapora-
tion was stopped when the liquid assumed the colour of an onion.
It was cooled down to 158°, and then dilute caustic ammonia
was added.
The success of the process depends upon the quantity of am-
monia, and on the temperature. The liquid should contain a
very slight excess of ammonia. It ought neither to be cold nor
hotter than 158° ; otherwise the compound is destroyed by the
free ammonia and another formed. The colour of the liquid is
so intense that it is opaque. We cannot therefore assist our-
selves in determining the requisite proportions by the reactions of
vegetable blues. The smell is the best means of determining if
the quantity of ammonia added be sufficient.
Dr Gregory of Aberdeen has^ given the following process for
preparing murexide: Dissolve seven grains of alloxane (con-
taining its water of crystallization), and four of alloxantin in 240
grains of water by boiling, and add the hot solution to 80 minims
of a cold strong solution of carbonate of ammonia. Collect the
crystals after some hours, slightly wash them with cold water, and
dry them by pressure between folds of paper.J
During and after the cooling are deposited the magnificent
crystals of murexide. They have a green colour and the metal-
* Jour. de Phys. Ixxxviii. 258. f Ann. de Chim. et de Phys. xxii. 33<t
Ann. der Pharra. xxxiii. 334.
MUREXIDE.
lie lustre. They are generally mixed with a red flocky powder ;
from which the crystals are easily freed by dilute ammonia, in
which the powder is soluble.
Sometimes when the temperature, during the addition of the
ammonia, has sunk too low, it was found advantageous, when the
quantity of ammonia added was sufficient, to pour into the liquid
its own bulk of boiling water. The crystals then were deposit-
ed slower, and were of remarkable beauty.
But the easiest process, and the one which yields murexide in
the state of greatest beauty, is the following: Mix equal weights
of uramile and red oxide of mercury with from twenty-four to
thirty times their weight of water, add caustic ammonia to the
mixture, and raise it gradually to a boiling temperature. A very
little ammonia is sufficient. The solution gradually acquires an
intense purple colour. When it begins to boil it is opaque, and
has a thick consistence. After allowing it to boil a few minutes
pass it through a filter. Generally flocks of uramile adhere to the
filter. They may be washed offend heated anew with red oxide
of mercury and ammonia. It yields, like the first solution, crys-
tals of murexide. The addition of carbonate of ammonia when
the liquid is almost cold generally occasions the formation of
more crystals.
The crystals of murexide are always small, never exceeding
three or four lines in length. They are short four-sided prisms,
two of the faces of which reflect the light of a metallic green co-
lour like the wings of cantharides, while the two other faces ex-
hibit a mixture of brown. When seen by solar light they have
a garnet red colour, and are transparent. Thus they resemble
in colour the beautiful crystals of sulphomolybdate of potassium.
When in powder the substance is red ; but under the burnisher
becomes green and assumes the metallic lustre.
Murexide is very little soluble in cold water, though it gives
it a deep purple colour. It dissolves more readily in hot water.
It is insoluble in alcohol and ether. A saturated solution of car-
bonate of ammonia scarcely takes up a trace of it. Hence this
salt may be employed with advantage to purify murexide from
substances which are soluble in it. It dissolves in caustic potash,
assuming a fine blue colour.
The formation of murexide is the result of the action of am-
monia upon the alloxane and alloxantin which exist in the nitric
ANIMAL OXIDES WITH AZOTE NOT OILY.
acid solution of uric acid. Wohler and Liebig have ascertain-
ed that both these substances are present, and the former in
greater proportion, and that the decompositions which take place
are very complicated.
If we boil a solution of alloxantin in ammonia till the colour
at first induced disappears, allow the liquid to cool down to 158°,
and then add a solution of alloxane, every drop we add the pur-
ple colour of the liquid increases in intensity, till at last it be-
comes quite opaque. Soon after we see formed on the sides of
the vessel and the surface of the liquid brilliant green crystals
of murexide. But the quantity of them is never proportional to
that of the substances employed. Sometimes these crystals are
mixed with red flocks of uramile, easily separated by washing
them cold in caustic ammonia.
The principal result of the action of ammonia on alloxantin
being the production of uramile, it was natural to think that the
formation of murexide depended on the action of alloxane on
uramile while ammonia was present. They found that when a
solution of alloxantin with sal-ammoniac or oxalate of ammonia
is heated till the decomposition was effected and the uramile
formed, if enough of ammonia be added to redissolve the preci-
pitate at first formed, and after that a solution of alloxane be
poured in, the colour becomes very intense, and murexide sepa-
rates in considerable quantity.
We obtain murexide in great beauty, though in no great quan-
tity, when, after having decomposed alloxantin by sal-ammoniac,
we filter oft7 the uramile formed and saturate the residual liquid
with carbonate of ammonia. Uramile dissolved in ammonia and
treated with alloxane always gives murexide.
The co-operation of alloxantin in the production of murexide
seems merely to consist in the formation of uramile ; but in
what way alloxane acts seems still an enigma.
Wohler and Liebig observed that a simple solution of uramile
in ammonia, evaporated by the assistance of heat, and boiled for
some time, assumes a deep purple colour, and gives, on cooling,
a great quantity of murexide. This would seem to prove that
alloxane does not contribute to the formation of this product, but
by abandoning a portion of its oxygen. This led them to try
whether other substances easily parting with oxygen might not
be substituted for alloxane.
MUUEXIDE. 123
They found that murexide may be prepared with great faci-
lity by putting uramile in boiling water, and adding by little and
little, small quantities of oxide of silver or oxide of mercury.
The oxides are reduced, the liquid assumes a deep purple colour,
and when filtered yields pure crystals of murexide. No gas is
given out during the process.
The slightest excess of oxide causes the red colour to disappear.
The liquid becomes colourless, and contains an ammoniacal salt,
which behaves with the salts of silver and barytes like alloxanate
of ammonia.
When the crystals of murexide are heated, they lose between
three and four per cent, of water.
The analysis of murexide occasions some difficulty, in conse-
quence of the readiness with which protoxide of azote is formed.
It was avoided by causing the gases to pass through very fine
copper filings raised to the requisite temperature. The propor-
tion of azotic gas to that of carbonic acid gas, the mean of four
experiments, was 2 '084 of the former, to 4*994 of the latter, or
as 2 I 4 '7 9, or very nearly as 5 : 12.
The mean of five analyses in Liebig's laboratory, by means of
oxide of copper, gave
Carbon, 33-61 or 12 atoms = 9-00 or per cent 33.97
Hydrogen, 3-00 or 6 atoms — 0-75 ... 2-83
Azote, . 32-70 or 5 atoms = 8-75 ... 33-01
Oxygen, 30-69 or 8 atoms = 8.00 ... 30-19
100-00 26-5 100-00
The formula C12 H6 Az5 O8 agrees very well with the analysis,
and its accuracy has been corroborated by Wohler and Liebig
by the following considerations :
Murexide is obviously not an ammoniacal salt; but an amide —
though a kind of amide hitherto without analogy. The problem of
the exact formula would have been easily resolved, if, by its
decomposition, it had only given two products like the amides.
But it gives origin to five different bodies, susceptible themselves
of being altered by the agents employed to destroy the murexide.
This leads to the supposition that secondary products are pre-
sent.
A boiling solution of murexide, treated by sulphuric or mu-
riatic acid, deposites in a short time pearly plates, which are white,
ANIMAL OXIDES WITH AZOTE NOT OILY.
yellow, or reddish, and which Prout has called purpuric acid
Liebig and Wohler have distinguished this substance by the
name of murexane.
SECTION VIII.-
We obtain this substance when we dissolve murexide in caus-
tic potash ; boil the liquid till the blue colour disappear, and then
pour into it dilute sulphuric acid. To obtain it pure, we have
only to dissolve the murexane thus obtained in potash, and pre-
cipitate it by an acid. It has then the form of a very light pow-
der, very porous, having a silky lustre, and becoming red when
exposed to the vapour of ammonia. It is insoluble in water and
in dilute acids ; but soluble without sensible alteration in con-
centrated sulphuric acid, from which it is precipitated by wa-
ter. It dissolves readily in the alkalies and in ammonia, but
without neutralizing them. When newly precipitated, it has a
great resemblance to uramile ; but it is easily distinguishable
both by its reaction and by its composition.
When burnt with oxide of copper, it gives azotic and carbonic
acid gases in the proportion 1 *. 3.
The mean of four analyses made in Liebig's laboratory gives
its compositions —
Carbon, 32-76 or 6 atoms = 4-5 or per cent 33-33
Hydrogen, 3-73 or 4 atoms = 0-5 ... 3-70
Azote . 25-48 or 2 atoms = 3-5 ... 25-93
Oxygen, 38-03 or 5 atoms = 5-0 ... 37-04
100-00 13-5 100-00
Murexane is not the only product of the decomposition of mu-
rexide. We find ammonia combined with the acid, which was
employed to throw down the murexane. It may be driven off by
the addition of a fixed alkali. If, after having decomposed mu-
rexide by dilute sulphuric acid, we separate the murexane by the
filter, there remains a colourless liquid, which possesses the fol-
lowing characters:
When placed in contact with nitrate of silver, it assumes a
black colour, and deposites in a short time metallic silver, just as
would happen to a solution containing alloxantin. Ammonia
forms in the liquor separated from the silver a dense white pre-
* Ann. de China, et de Phys. Ixviii. 322.
MUREXANE. .
cipitate, which becomes yellow on boiling, without dissolving.
In this respect it agrees with a solution of alloxane mixed with
ammonia.
If we decompose murexide by muriatic acid, separate the mu-
rexane, and add barytes water to the acid liquid, a dense preci-
pitate falls of a light violet colour. This reaction indicates the
presence of alloxantin. The precipitate is not of so deep a vio-
let as with pure alloxantin, but it is not colourless like that from
pure alloxane. A current of sulphuretted hydrogen instantly
destroys the colour of the murexide. Silky plates of murexane
precipitate ; and the liquid gives with barytes water a deep vio-
let precipitate, while ammonia is disengaged. It is obvious that
the alloxane become free is changed by the sulphuretted hydro-
gen into alloxantin.
When we boil murexide with a solution of potash till the deep
indigo blue colour disappear, precipitate the murexane by mu-
riatic acid, and neutralize the liquid exactly with ammonia, it
does not precipitate the salts of lime and barytes. But if we add
a new dose of ammonia, dense white flocks fall, which disappear
when we add a large quantity of water. This reaction charac-
terizes the alloxanates of lime and barytes.
If, after having decomposed murexide by dilute sulphuric acid,
we pour barytes water into the cold liquid, as long' as a precipi-
tate continues to fall, the whole sulphuric acid, and along with
it all the alloxane and alloxantin, except a mere trace, are pre-
cipitated. The filtered solutions being treated with carbonate of
ammonia to separate the free barytes, filtered anew, and evapo-
rated to a small bulk, gives with nitric acid crystals of nitrate of
urea.
The solution obtained by the decomposition of murexide by
means of sulphuric acid being neutralized by carbonate of am-
monia, and evaporated in a very gentle heat, loses, after some
time, the red colour which it had assumed. It gives a crystal-
line mass, in which it is easy to recognize alloxanate of ammonia
mixed with sulphate. The same solution being treated with am-
monia and a salt of silver, gives a white precipitate, which, by
the action of a gentle heat, becomes black while gas is disengaged,
and is reduced to metallic silver.
From all these reactions, it results that murexide produces, by
its decompositions by acids and alkalies, five different products,
126 OXIDES WITHOUT AZOTE NOT OILY.
namely, ammonia, murexane, alloxane, alloxantin, and urea.
Wohler and Liebig consider it as a combination of various
amides. Yet the decomposition of thionurate of ammonia when
decomposed by the acids gives a greater number of products
than even murexide.
CHAPTER II.
OXIDES NOT CONTAINING AZOTE, AND NOT OILY.
THESE bodies have been hitherto very imperfectly investigated.
We can enumerate in the present state of our knowledge only
four such substances, namely,
1. Melain. 3. Diabetes sugar.
2. Oonin. 4. . Sugar of milk.
These bodies will constitute the subject of the following sections :
SECTION I. OF MELAIN.*
This name has been given by Bizio to the black matter which
constitutes the essential constituent of the ink of the cuttle-fish.
Jt was first examined by Mr G. Kempf in the year 1813, after-
wards by Dr Prout in 1815 ;J and finally by Bizio. §
The black liquor of the cuttle-fish is secreted in a bag or blad-
der situated near the ca3cum, which communicates by a narrow
duct, with an opening in the upper part of the belly of the fish.
When chased by other fishes, the cuttle-fish is said to discharge
a quantity of this liquid, which, by rendering the water muddy,
enables it to escape from its enemies. Dr Prout found that when
the black matter in this ink is mixed with water, it takes at least
a whole week to subside. It is therefore admirably adapted for
the purposes of concealment.
The ink of the sepia when fresh is a black glairy liquid, of a
viscid consistence, a peculiar fishy smell, and very little taste.
When allowed to dry in its bladder, it becomes hard and brittle,
has an imperfectly conchoidal fracture, a brownish-black colour,
and exhibits a slight peacock-tail lustre on exposure to a strong
* From fixate, black. f Nicholson's Jour, xxxiv, 34.
| Annals of Philosophy, v. 417. § Brugn. Jour, xviii. 18.
MELAIN. 127
light. When in powder, it has a fine velvet black colour, has no
smell, it taste is saltish, and its specific gravity about 1-640.
Dr Prout analyzed a portion of this dry matter, and found its
constituents as follows :
Melain, . 78-00
Carbonate of lime, 10-40
Carbonate of magnesia, 7-00
Common salt? \ 2.ig
Sulphate of soda, /
Mucus, . . 0-84
98-40
Melain has a fine full black colour, and possesses the shining
appearance of powdered charcoal. It is insoluble in muriatic
and sulphuric acids, even when assisted by heat ; and also in
acetic acid. Concentrated nitric acid acts on it readily, and with
considerable energy, abundance of red fumes being emitted,
and at length a partial solution being formed of a very deep
reddish-brown colour. Potash added to this solution occasions
no precipitate ; but carbonate of potash occasions a slight
one. Caustic potash ley, when assisted by heat, effects a partial
solution of melain. So does caustic ammonia, but in a slighter
degree. The colour of these alkaline solutions is a darker brown
than of the solutions in nitric acid. When muriatic or sulphu-
ric acid is dropt into the alkaline solution, a slight precipitate
falls ; but this does not happen when nitric acid is employed.
Melain burns without melting and with considerable difficulty,
emitting the usual smell of burning animal matters, somewhat
modified by a fishy odour. When burnt, it left a minute portion
of reddish ashes, consisting of a mixture of peroxide of iron, lime,
and magnesia.
Melain is insoluble in water, but mixes with that liquid readily
and remains long suspended ; but the addition of the mineral
acids or ammonia causes it to subside rapidly. It is insoluble in
alcohol and ether.
Melain may be obtained from the dried ink of the cuttle-fish
by boiling that substance in water till every thing soluble in that
liquid is taken up. It is then treated in the same way succes-
sively by alcohol and muriatic acid. Thus purified, it is to be
well-washed with water, containing towards the end a little car-
bonate of ammonia.
128 OXIDES WITHOUT AZOTE, NOT OILY.
SECTION II. OF OONIN.
This name (from <wov, an egg,) has been given to a peculiar
principle which M. Couerbe extracted from the albumen of an
egg in the year 1829, and to which he gave at first the name of
albuminin, but afterwards changed for oonin*
M. Couerbe left a concentrated solution of albumen from an egg
in water, in a temperature varying from 32° to 18°. The solu-
tion became thick without congealing, and in about a month de-
posited a membranous net-work, which was pretty abundant.
This membranous matter is solid, white, translucent, com-
posed of membranes, tasteless, and without smell. It was easily
reduced to powder.
When heated in a glass tube, shut at one end, it is decomposed
without melting, and yields no ammonia. During its calcination
it swells, and leaves a bulky charcoal difficult to burn. When
decomposed by oxide of copper and heat, it gives nothing but
water and carbonic acid gas.
It is insoluble in water, though it is softened by that liquid.
In boiling water it swells without dissolving, and assumes the ap-
pearance of insoluble mucor.
Alcohol, ether, and acetic acid have no action on it whatever,
either cold or hot. It swells slightly in concentrated sulphuric
acid while cold ; but if we apply a gentle heat, the oonin is ra-
pidly charred, and gives out an agreeable smell. When water
is added, the charred matter precipitates, leaving a colourless di-
lute acid. Cold nitric acid acts but feebly on oonin ; but when
heat is applied, it dissolves it with the evolution of deutoxide of
azote. The best solvent of oonin is hot muriatic acid. The so-
lution is colourless, and no precipitate falls when it cools ; but if
we add water, the liquid becomes muddy, and a white precipi-
tate falls in the state of a very fine powder.
Alcoholic solution of potash dissolves it with the assistance of
a little heat When the liquid cools no precipitate appears. If
we saturate the alkali with muriatic acid, the mixture becomes
muddy ; but no precipitate falls during twenty-four hours.
These experiments of Couerbe were repeated and confirmed by
MM. Soubeiran, and Henri, Jun.f
• Ann. de China, et de Phys. xli. 323.
\ Jour, de Pharm. xv. 495, and xix. 299.
DIABETES SUGAR.
SECTION III. - OF DIABETES SUGAR.
It is now universally known that in the disease called dia-
betes, the urine contains a considerable quantity of sugar, which
may be easily extracted in a state of purity. The sweet taste of
diabetic urine, and, of course, the existence of sugar in it, seems
to have been first observed by Dr Willis. Sydenham, though he
describes the disease, and distinguishes it by the name of diabe-
tes, takes no notice of the sweet taste of the urine, but only of
its great quantity.* The first person who attempted to obtain the
sugar in a separate state was Mr Cruikshanks. He gives an ac-
count of his experiments in an appendix to Dr Rollo's book on
Diabetes, which was published in 1797. He extracted from dia-
betic urine about one- twelfth of its weight of a sweet tasted ex-
tract like honey.
In 1815, Chevreulf analyzed diabetic urine, and extracted
from it the sugar in a state of purity. He found that the shape
of the small crystals which it formed (small spherules) was pre-
cisely the same as that of grape sugar. It possessed all the
qualities of that sugar, has the same solubility in water and alco-
hol, and like grape sugar melts when exposed to a gentle heat.
From these facts, Chevreul concluded that diabetic sugar was
precisely the same with that of grapes. Cruikshanks had already
compared it to honey ; and we now know that sugar of honey is
identical with that of grapes. M. Calloud| found diabetic and
grape sugar to agree also in another property, namely, that of
combining with common salt and forming crystals which have the
form of dodecahedrons composed of two six-sided pyramids
applied base to base, or sometimes of rhomboids. According to
Calloud these crystals are composed of,
Common salt, . 8.3
Sugar, . . 91-7
-
100-
This differs essentially from Brunner's analysis, which I have
given in the Chemistry of Vegetables, p. 638. Calloud's analy-
sis would indicate four atoms of sugar to one of common salt, while
Brunner's make the compound to consist of an atom of each con-
stituent. But when he combined common salt directly with
* Opera, p. 271. t Ann. de Chirn. xcv. 319.
Jour, de Pharmacie, xi. 562.
130 OXIDES WITHOUT AZOTE NOT OILY.
sugar of grapes, he obtained a compound exactly coinciding
with Brunner's, since it consisted of,
Common salt, . 28
Sugar, . 75
100
In some rare cases of diabetes, the quantity of common salt in
the urine is so great, that, by evaporating it by a gentle heat,
crystals are deposited consisting of common salt combined with
diabetes sugar.
Sugar of diabetes was first analyzed by Dr Prout.* He found
it composed of
Carbon, 36- to 40-
Hydrogen, 7*11 to 6-66
Oxygen, 56*89 to 53-34
100-00 100-00
But these differences are too great to enable us to deduce the
constitution of diabetes sugar from the analysis. Peligotf ana-
lyzed diabetes sugar with great care in 1838, and found its con-
stituents to be
Carbon, . 35'88
Hydrogen, . 7-44
Oxygen, . 56-68
100-00
This gives the formula,
12 atoms carbon, . = 9*00 or per cent 36-36
14 atoms hydrogen, =1-75 ... 7-07
14 atoms oxygen, = 14-00 ... 56*57
24.75 100.00
This is obviously the same constitution which sugar of grapes
has. By heat diabetes sugar may be deprived of two atoms of
water, and thus it becomes,
» Phil. Trans. 1827, p. 373. f Ann. de Chim. et de. Phys. kvii. 142.
6
SUGAR OF MILK. 131
12 atoms carbon, . — 9*0 or per cent. 40'
12 atoms hydrogen, =1*5 ... 6-6(5
12 atoms oxygen, = 12- ... 53-34
22-5 100,00
I found that, by combining it with certain bases, it might be
deprived of another atom of water, and thus reduced to
12 atoms carbon, = 9* or per cent. 42.11
11 atoms hydrogen, = 1-375 ... 6-43
11 atoms oxygen, = 11- ... 51-46
21-375 ... 100-
Thus it is identical with grape sugar in its constitution. Hence
the reason why diabetic urine is so apt to ferment and evolve
alcohol.
SECTION IV. OF SUGAR OF MILK.
Sugar of milk may be extracted from whey in the following
manner : Evaporate the whey to the consistence of a syrup, and
set it aside for some weeks in a cool place. Granular crystals
of sugar of milk will be deposited. To obtain it pure we must
redissolve it in water, and crystallize it a second time. And this
process must be repeated two or three times.
Fabricius Bartholetti, an Italian, was the first European who
mentioned this sugar. He described it in his Encyclopedia
Hermetica-Dogmatica, published at Boulogna in 1619;* but it
seems, from what Haller says, to have been known in India long
before that time. It is manufactured in large quantities in
Switzerland, from which country all the sugar of milk of com-
merce comes. The person who chiefly contributed to make su-
gar of milk generally known, was Ludovico Testi, who gave it
out as an invention of his own, and sold it as a powerful remedy
in the gout and other diseases. He was a physician in Venice,
where he died in 1707. After his death Valisneri published
the process which Testi employed in extracting his sugar from
whey.
Sugar of milk is white, and crystallizes in right four-sided
prisms, usually terminated by four-sided pyramids. It has a
* According to Beckman, he called it manna, seu nitrum seri lactis. His.
tory of Inventions, ii. 494.
OXIDES WITHOUT AZOTE NOT OILY.
taste only slightly sweetish. Its specific gravity at the tempera-
ture of 55° is 1-543. At 59° it is soluble in 5 times its weight
of water, and 2£ times its weight of boiling water. When the
crystals are melted they lose 12 percent, of water. When thus
fused the sugar is transparent and colourless. On cooling it
concretes into a white opaque mass. It dissolves but slowly in
water. But the solution may be evaporated much beyond the
crystallizing point without any crystals forming. It is scarcely
soluble in absolute alcohol ; but its solubility is increased when
the alcohol is diluted with water. In ether it is insoluble.
When long boiled in dilute sulphuric acid it is converted into
sugar of grapes. Nitric acid converts it into oxalhydric, oxalic,
and mucic acids. When in powder it absorbs muriatic acid gas
in great quantity, and assumes the form of a grey coherent mass.
It absorbs also ammoniacal gas, and when completely saturated
the weight augments from 100 to 112.4 or the compound of su-
gar of milk and ammonia is composed of,
Sugar of milk, . 100- or 17.137
Ammonia, . 12-4 or 2-125
Caustic potash converts it into a brown, bitter tasted substance,
which is insoluble in alcohol.
When digested with oxide of lead at a temperature not ex-
ceeding 122°, a combination takes place. The liquid is a solu-
tion of oxide of lead holding in suspension an insoluble com-
pound, which may be obtained by filtering in a covered vessel to
exclude the carbonic acid of the atmosphere. It is mucous, and
when dried becomes gray and translucent. At 212° it loses
water and becomes yellow. It is composed of,
Sugar of milk, . 36-47 or 8.018
Oxide of lead, 63-53 or 14'
100-00
The filtered liquid contains a soluble compound of sugar of
milk, and oxide of lead. Its taste is at once sweet, alkaline, and
styptic. When evaporated in vacuo it leaves a yellow transpa-
rent substance resembling gum, which is soluble in water. It is
composed of,
Sugar of milk, . 81-88tor 63*117 = 8.018 + 8
Oxide of lead, . 18-12 or 14-
100.00
SUGAR OF MILK. 183
If we add ammonia to the soluble compound, the insoluble
compound, noticed above, falls down. If we digest it for a long
time with an excess of oxide of lead we obtain a subsalt compos-
ed of,
Sugar of milk, . 12-55 or 8-
Oxide of lead, 87-45 or 55-74 = 14 x 4
100.00
Sugar of milk was first subjected to an ultimate analysis by
Gay-Lussac and Thenard.* Berzelius analyzed it in 1815,f
Prout in 1827,J Liebig in 1834,§ and Brunner in 1835.|| The
following table exhibits the result of these analyses :
andyTh"Snard Berzelius- Prout. Liebig. Brunner. Mean.
Carbon, 38-825 39474 40.00 3951 40-437 39-649
Hydrogen, 7-341 7-167 6-66 6-74 6-7J1 6-926
Oxygen, 53-834 53-359 53-33 53.75 52-852 53.425
100-000 100-000 100-00 10000 100-000 100-000
These experiments exhibit the constitution of sugar of milk in
crystals. They lead to the formula,
12 atoms carbon = 9 or per cent. 40
12 atoms hydrogen = 1-5 ... 6-66
12 atoms oxygen =12-0 ... 53-33
22-5 100-00
But, according to Berzelius, 100 parts of crystals of sugar of
milk when dried at 212°, or when combi»ed with oxide of lead,
lose 12 of water. Hence 22-5 would lose 2-7 of water or 2J
atoms. Let us suppose the loss to be only 2.25 or two atoms
water, then it would follow that anhydrous sugar of milk is com-
posed of,
12 atoms carbon, — 9 or per cent. 44-44
10 atoms hydrogen, = 1-25 ... 6-18
10 atoms oxygen, = 10- ...49-38
20-25 100-00
This is precisely the constitution of anhydrous cane sugar. Yet
the properties of the two differ exceedingly from each other.
* Recherches Physico-Chimiques, ii. 295.
t Annals of Philosophy, v. 266. J Phil. Trans. 1827, p. 383.
§ Annalen der Pharmacie, ix. 24. || Poggendorf a Annak M, xxxiv. 335.
OILY OXIDES, SAPONIFIABLE.
It is a generally received opinion that sugar of milk is inca-
pable of fermenting, or of being decomposed into carbonic acid
and alcohol. But the well-known fact, that the Tartars and the
inhabitants of the Shetland Islands make an intoxicating liquor
by fermenting milk, is inconsistent with this opinion, and proves
that sugar of milk when properly treated may be made to fer-
ment as well as common and grape sugar. Doubtless, like com-
mon sugar, it is first converted into sugar of grapes before it
can be capable of fermenting or of being decomposed into alco-
hol and carbonic acid.
CHAPTER III.
OF OILY OXIDES, SAPONIFIABLE.
THE terms fat, tallow, suet, lard, &c. are applied to a secre-
tion of an oily nature, usually solid in the hot-blooded, and
fluid in cold-blooded animals. This substance is deposited in
the cellular substance. The quantity formed depends in some
measure upon the food ; and when the food becomes deficient,
or the power of digestion imperfect, the fat disappears. It is
deposited in the cellular tissue of all animals, but the fat of only
a small number of species has hitherto been examined by che-
mists. Of these the following are the most important : —
*
1. HOG'S LARD.
This is the fat of the Sus scrofa, or common hog. It is depo-
sited to a considerable thickness immediately under the skin
of the domestic animal. It is white, and has very little smell ;
but when we melt it in contact of boiling-water, the smell becomes
strong and disagreeable. It melts completely at 99°, and then has
the appearance of a transparent and nearly colourless fixed oil.
A thermometer placed in it sinks gradually to 80°. The lard
then begins to congeal, and the thermometer remains at 80° all
the time of congealing, which occupies several minutes. It is
clear from this that 80° is the melting point of hog's lard.
Its specific gravity at 102° is 0*9028 ; at 60° it is 0-9302.
When hog's lard is left exposed to the air, it becomes gra-
dually yellow-coloured and rancid, acquires a strong smell, and
reddens vegetable blues. A volatile fatty acid is developed, th
OX FAT. 135
nature of which has not yet been examined, but Chevreul consi-
ders it as analogous to caproic acid.
Hog's lard, like all the other varieties of fat, has been shown
by Chevreul to consist of two distinct oily bodies ; the one solid
at the ordinary temperature of the atmosphere, and the other li-
quid at the same temperature. The first on that account has
been called stearin ; the second elain. Braconnot showed that
if hog's lard be subjected to pressure between folds of blotting-
paper, the elain is absorbed by the paper while the stearin re-
mains. According to his experiments, hog's lard is composed of
Elain, . 62
Stearin, . 38
100
The elain has a specific gravity of 0'915. 100 parts of abso-
lute alcohol dissolve 123 parts of it.
The stearin is without smell, translucent, dry, and granular.
It melts when heated to 109^°. On congealing, it assumes an
imperfectly crystallized texture.
It has been shown that stearin is a compound analogous to a salt,
consisting of stearic add combined with glycerin. In like man-
ner, elain is a compound of oleic acid and glycerin. If we di-
gest lard with caustic potash ley, the acids gradually combine
with the potash, and constitute with it a soap while the glycerin
is disengaged. In this way it has been ascertained that pure
lard is composed of
Stearic and oleic acids, 94'65
Glycerin, . 9
When hog's lard is digested with nitric acid it is converted
into oleic and margaric acids.*
2. ox FAT.
The fat of oxen has a yellowish-white colour, and a slight but
peculiar smell. It melts when heated to 100°. Boiling alcohol
of 0'82,1 specific gravity dissolves about the fortieth part of its
weight of this fat.
Like hog's lard it is a mixture of stearin and elain. But, as it
is much firmer and harder than lard, we might infer that the
proportion of stearin which it contains is much greater than in
* Bussy and Lecanu, Jour, de Phartn. xii. 605.
136 OILY OXIDES, SAPONIFIABLE.
lard. And this is the case. The stearin constitutes about thre e-
fourths of ox tallow. It is now separated on a great scale to be
manufactured into candles. The method employed is to melt
the tallow, and to stir it incessantly while in the act of congeal-
ing. It is then exposed to pressure in woollen cloths at the
temperature of 95°. The elain forced out still retains a consi-
derable quantity of stearin. This elain is cooled flown a few de-
grees below 95°, and subjected to pressure again, by which an
additional portion of stearin is obtained. And this process is re-
peated sinking the temperature every time, till at last it is re-
duced as low as 36°. At last an elain is obtained, which is quite
liquid, and which does not become solid though cooled down se-
veral degrees below 32°.
The stearin thus obtained is white, granular, and crystalline.
It melts at 111°, and may be cooled down to 102° before it be-
gins to congeal ; but then the temperature rises to 1 1 1°, and con-
tinues so till the whole stearin is congealed. This stearin has
about the same translucency as white wax. Its feel is not greasy,
and it burns with a light similar to that of wax ; 100 parts of
absolute alcohol at the boiling temperature dissolve 15-48 parts of it.
The elain from ox fat is colourless, and almost without smell.
Its specific gravity is 0-913. 100 parts of absolute alcohol dis-
solve 123-4 of it at the temperature of 167°.
Candles made of the stearin of ox tallow are little inferior to
wax candles. The stearin being brittle and apt to crystallize, it
has been found necessary to mix it with a little white wax, in
order to deprive it of these qualities.
There is an oil obtained from the feet of oxen, and therefore
known in this country by the name of Neat's Foot Oil, which de-
serves to be noticed. It remains liquid though cooled down to
below 32°, and therefore is used very much to oil machinery, in
order to diminish friction.
To obtain it tlie hair and hoofs are removed, and the inferior
part of the bone of the foot being rasped down is boiled in water
together with the surrounding parts. The oil swims on the sur-
face of the water. It is nearly colourless, and may be kept a con-
siderable time without alteration ; but at last it deposites some
solid matter having the aspect of stearin.
3. MUTTON SUET.
This is the name by which the fat of the sheep (Ovis aries)
GOAT FAT HUMAN FAT. 137
is known in this country. It resembles ox fat, but is whiter.
When fresh it has hardly any smell. Some varieties of it melt
at 100° ; others not till 104°, or even 106°. It dissolves in 44
times its weight of boiling alcohol of 0-821 specific gravity.
Its stearin is white and without lustre. It begins to solidify
at 99^°, and the temperature then rises to 111°. On congealing
it crystallizes imperfectly. It is translucent. One hundred parts
of boiling absolute alcohol dissolve 16-09 of it. The elain of mut-
ton suet is colourless, has a slight odour of mutton, and a specific
gravity of 0'913. One hundred parts of absolute alcohol dis-
solve 80 parts of it at the temperature of 167°.
4. GOAT FAT.
This fat resembles that of the ox, but it has a peculiar and dis-
agreeable smell, similar to that of the animal. It is owing to the
presence of a peculiar oily matter to which Chevreul has given
the name of hircin, and which has been very imperfectly examin-
ed. It exists also in small quantity in mutton suet. It is liquid,
and is found in the elain when goat fat is separated into elain
and stearin. Though hircin has not yet been obtained se-
parate from elain, Chevreul succeeded in obtaining hircic acid,
which is presumed to be one of the constituents of hircin.
He obtained it in the following way : Four parts of goat fat
were saponified by digestion in one part of hydrate of potash
dissolved in four parts of water. The soap is decomposed by
phosphoric or tartaric acid. The fatty acids are separated and
washed, and the washings mixed with the acid residue of the
decomposed soap. This liquid is distilled.* The liquor that
passes over contains the hircic acid. Saturate it with carbo-
nate of barytes and evaporate to dryness, and decompose by dis-
tilling it with equal weights of sulphuric acid and water. The
hircic acid will be found swimming on the water in the receiver
under the form of a colourless volatile oil.
5. HUMAN FAT.
This fat is softer than either ox fat or mutton suet. It has a
yellow colour, and its melting point seems to vary. Chevreul
found fat from the kidney, when melted at 104°, begin to con-
geal at 77°. At 75^° it was semifluid, and at 62|° it was con-
* If the matter in the recipient leaves any stain on platinum foil when eva-
porated, it must be distilled again.
138 OILY OXIDES, SAPONIFIABLE.
gealed into a mass in which might be distinguished a white so-
lid matter and a yellow oil. Another specimen from the thigh
continued quite fluid at 59°. When kept for some days at that
temperature in a close flask it deposited a solid matter ; but af-
ter an interval of a fortnight it was still partly liquid, a yellow
oil floating on the solid portion. These variations in the congeal-
ing point depend upon a variation in the proportion of the stearin
and elain in this fat.
Human fat is soluble in 40 times its weight of hot alcohol of
0-821. On cooling the liquid deposites stearin, which, after be-
ing again dissolved in hot alcohol and deposited, and exposed to
pressure between the folds of blotting-paper, possesses the follow-
ing properties : It is colourless, has little lustre, and melts at
122°. It may be cooled down to 106° before it begins to con-
geal, but the instant congelation begins the heat rises to 120°.
The stearin crystallizes in a mass composed of small needles.
One hundred parts of boiling absolute alcohol dissolve 21*5 of
this stearin. But the greatest part precipitates when the solu-
tion cools. The elain is a colourless oil which remains liquid
though cooled down to 25°, but congeals into needles at a few
degrees below that temperature. Its specific gravity at 59° is
0'913. It has no smell but a sweetish taste. One hundred
parts of boiling alcohol dissolve 123 of this elain, and the solu-
tion becomes muddy when cooled down to 170^°.
One hundred parts of human fat when saponified yield,
Margaric and oleic acids, 95 '24 to 96*18
Glycerin, . . 9-66 to 10
The mixture of margaric and oleic acids melt between 88° and
95°. The stearin gives 8 '6 of glycerin with 94'9 of fatty acids,
in which there is no stearic acid, and which melt at 124°. The
elain gives 9 '8 of glycerin and 95 of fatty acids fusible at be-
tween 93° and 95°.
Fourcroy described under the name of adipocirin, a fat obtain-
ed from dead bodies which had been long piled up together, and
which he considered a combination of a peculiar fatty matter with
ammonia. Chevreul has shown that it is merely human fat sa-
ponified (doubtless by ammonia) ; and of course a combination
of margaric and oleic acids with ammonia.
6. GOOSE FAT.
It is colourless, and has a peculiar taste and smell, rather agree-
DUCK FAT. — TURKEY FAT. WHALE OIL. 139
able. If melted it congeals at 80J° into a granular mass, hav-
ing the consistence of butter. When exposed to pressure be-
tween folds of blotting-paper at 28^° it is resolved, according to
Braconnot, into,
Stearin, . 32 fusible at 111°
Elain, . 68
100
The elain is yellowish white, and has a peculiar taste. One hun-
dred parts of boiling absolute alcohol dissolve 36 parts of the
stearin. When saponified it yields,
Margaric and oleic acids, . 94*4
Glycerin, . . .8-2
The specific gravity of the elain is 0'929. One hundred parts
of absolute alcohol at 167° dissolve 123^° of it It begins to
precipitate when cooled down to 124°. When saponified it gives
89 per cent, of fatty acids.
7. DUCK FAT.
It melts at 77°. Braconnot resolved it into
Stearin, . 28 fusible at 126J0
Elain, . 72
100
The elain has the peculiar taste and smell which characterizes
duck fat.
8. TURKEY FAT.
It was resolved by Braconnot into,
Stearin, . 26 fusible at 113°
Elain, . . 74
100
9. WHALE OIL.
This well known oil is obtained by boiling the blubber of the
Balena misticetus or great northern whale. Its colour is brown,
and it has a disagreeable fishy smell. Its specific gravity is 0-927.
It boils at about 620°. When distilled over we obtain a much
more fluid brown oil which boils at 410°.
140 OILY OXIDES, SAPONIFIABLE.
"When cooled it deposites stearin, which may be separated by
the filter. When boiled in alcohol it becomes deeper coloured,
and the elain is separated. One hundred parts of absolute alco-
hol dissolve at a boiling temperature 55^ of stearin. When the
solution is cooled it deposites first white brilliant crystals, and then
yellowish coloured crystals, and there remains a thick brown li-
quor, which has not been examined. When this stearin is sapo-
nified we obtain glycerin, some phocenic acid, and 38*9 per cent,
of fatty acids.
The elain is not decomposed by alcohol. One hundred parts
of boiling absolute alcohol dissolve 122 parts of it. When treat-
ed with half its weight of hydrate of potash it is easily saponified ;
glycerin being evolved together with a little phocenic acid and
margaric and oleic acids. The oleic acid has a fishy smell, which
it communicates to its salts.
10. OIL OF THE DELPHINUS PHOCENA OR PORPOISE.
This oil is liquid, and has a yellow colour. It has at first a
fishy smell, which goes away when the oil is exposed to the sun
and air. Its specific gravity is 0-937. When exposed to the
air it acquires at first a brown colour, which gradually disappears.
It then acquires the smell of oil of colza, and reddens vegetable
blues. 100 parts of boiling alcohol of 0-821 dissolve 20 parts
of the oil ; but the solution becomes muddy on cooling. But
when we boil together equal parts of the oil and alcohol, no pre-
cipitate appears, and we may add more oil almost in any propor-
tion.
When saponified this oil yields,
Margaric and oleic acids, . 82-2
Glycerin, . . 16
Together with a certain quantity of phocenic acid.
11. OIL OF DELPHINUS GLOBICEPS.
This oil is fluid, and has a light lemon-yellow colour, and a
fishy smell. Its specific gravity is 0-918. 100 parts of absolute
alcohol at 68° dissolve 123 parts of it. When cooled slowly to
the point of congelation, or a little below it, this oil deposites a
cetin, similar to that from the Pliyseter macrocephalus, but not
quite identical with it.
When melted, this cetin begins to congeal at 114°, and it is
FAT OF COCHINEAL INSECT. 141
totally solidified at 110°. 100 parts of boiling alcohol of the spe-
cific gravity 0-834 dissolve 2-9 parts of it. It is not so easily
saponified as the cetin of the macrocephalus, furnishes less ethal,
and a greater quantity of fatty acids. The ethal from this oil
melts at 1 16J°, while that from the macrocephalus melts at 1 18 J°.
The oil from which this cetin has been deposited is perfectly
liquid at 68°, and at 59° resembles butter. Its specific gravity
is 0-924 ; 100 parts of alcohol of 0-820 dissolve 149.4 parts of
it before beginning to boil. By saponification, 100 parts of this
oil give 66 parts of margaric and oleic acids, along with which
are 14-3 of a fat not saponifiable, and similar to ethal, only more
fusible, and in fact composed of two fats, of which one melts at
80J0, and the other at 95°. They may be separated from the
fatty acids by the same means as those employed to isolate the
ethal. The saponification produces also 15 parts of glycerin,
and a considerable quantity of phocenic acid.
12. FAT OF COCCUS CACTI OR COCHINEAL INSECT.
In the year 1818, MM. Pelletier and Caventou made a set of
experiments on the fat of this insect* It was extracted by them
by means of ether, which forms with it a yellow solution ; the
ether being evaporated away, the fat remains. To obtain from
it a colourless stearin, we must dissolve it repeatedly in water,
and crystallize it. The crystals are white pearly plates. This
stearin melts at 104°, and is but little soluble in cold alcohol.
When we distil off the alcohol, a little solid fat separates, and
there remains an elain, which continues liquid at 32°, and which
is coloured yellowish-red by the colouring matter of the cochi-
neal insect. It still retains a small quantity of stearin in solu-
tion. This elain is easily saponified. It gives fatty acids, and a
volatile odorous]acid. The Coccus polonicus contains more fat than
the Coccus cacti Two specimens of it, the one moist and the
other dry, were examined by Berzelius, who found the acids
which they yielded similar to those in butter. f
All these fatty or oily substances from animals, and many
others which have not hitherto been examined, are divisible into
two distinct substances, the one solid and called stearin, the other
liquid at the common temperature of the atmosphere, and called
* Ann. de Chim. et de Phys. viii. 270.
f Traite de Chimie, vii. 551.
142 OILY OXIDES, SAPONIFIABLE.
elain. Some fatty bodies yield oils having different properties
from elain. Those that have been examined by Chevreul are
Phocenin, Butyrin, and Hircin. The mode of obtaining these
bodies and their properties have been already described in the
Chemistry of Inorganic Bodies, (Vol. ii. 35.)
Chevreul analyzed the stearin and elain from different fatty
bodies, as human fat, hog's lard, mutton suet, &c. He found
them all compounds of carbon, hydrogen, and oxygen. But the
proportions were not the same in all. Whether this difference
was owing to any diversity in the various stearins and elains, or
to the presence of foreign bodies in greater or smaller quantity,
we have no means of determining.
It has been ascertained that stearin is a compound of stearic
or margaric acid and glycerin, which performs the part of a base.
Stearic acid has been shown by the analytical researches of Messrs
Redtenbacher, Varrentrapp, and Bromeis * to be C68 H66 O3
= 64-25.
In its common state it is a hydrate composed of C68 H66 O5
+ 2 (HO).
Stearates of silver and lead are composed as follows :
Stearate of silver, . C68 H66 O5 + 2 (Ag O)
Stearate of lead, . C68 H66 O5 + 2 (Pb O)
The two atoms of the oxides of silver and lead taking the place
of the two atoms of water in the hydrated acid.
Dr Redtenbacher also formed stearic ether, or, as it is now
called, stearate of oxide of ethyle, by dissolving stearic acid in
alcohol and passing a current of muriatic gas through the solu-
tion till it refused to absorb more. Its composition was
, 1 atom stearic acid, . C68 H66 O5 = 64-25.
1 atom ether, . C4 H5 O = 4-625.
1 atom water, . H O = 1-125.
70
Margaric acid was obtained by M. Redtenbacher and M. Var-
rentrapp by distilling stearic acid. Its constitution is C34 H33
O3 = 32-625.
Hydrated margaric acid is C34 H33 O3 + HO = 33-75.
Margarate of silver is C34 H33 O3 -f Ag O. The atom of oxide
of silver taking the place of the atom of water in the hydrate.
* Annalen der Pharmacie, xxxv. 46, 65, and 86.
FAT OF COCHINEAL INSECT. 143
These two acids have an obvious relation to each other. We
may consider them as consisting of a common radical, C34 H33,
united to oxygen.
Margaric acid will be . C34 H33 + O3
Stearic acid, , . 2 (C34 H33) + O5
The margaric acid is a compound of one integrant particle of
the radical united to 3 atoms oxygen, while the stearic acid con-
tains two integrant particles of the radical united to five atoms
oxygen.
Stearic acid was discovered by Chevreul in 1816, and called
at first margarous acid ; but he afterwards adopted the term stea-
ric acid) * as more proper. To obtain it we must saponify mut-
ton suet, ox's fat, or hog's lard. The soap must be dissolved in
a weak solution of caustic potash. The solution is to be mixed
with a quantity of water forty-five times as great as that of
the tallow saponified. The mixture being left at rest in a tem-
perature between 50° and 60°, there gradually falls to the
bottom a pearly looking substance, which is a mixture of bistea-
rate, bimargarate, and superoleate of potash. This substance
is allowed to dry. It is then washed three times successively in
eight times its weight of boiling alcohol of 0-820. The first of
these, on cooling, deposites a great quantity of crystals consist-
ing chiefly of bistearate of potash. It is rendered quite pure by
repeated solutions in alcohol, and crystallizations. It is then
decomposed by tartaric or muriatic acid.
Thus prepared, stearic acid melts when heated to 158°. Red-
tenbacher found the melting point of the stearic acid which he
prepared 160°. On cooling, it crystallizes in fine brilliant
needles, interlaced with each other. It is tasteless, destitute of
smell, and insoluble in water. While in a liquid state, it com-
bines with alcohol in all proportions. If at the temperature of
167°, we mix equal weights of stearic acid and alcohol, we ob-
tain a solution which, when cooled down to 122°, crystallizes in
brilliant plates. At 113° the whole congeals into a solid mass.
Ether of 0-725 density dissolves its own weight of stearic acid
when assisted by heat. The solution is limpid at 140°. At
1344° it concretes into a mass formed of beautiful plates. This
acid readily combines with the alkalies, and forms a soap. One
* From rrttt£, tallow.
144 OILY OXIDES, SAPONIFIABLE.
atom of stearic acid usually combines with two atoms of base.
Thus pure stearate of soda is composed of,
1 atom stearic acid, . = 64 25
2 atoms soda, . . — 8*
2 atoms water, . . =2.25
74-5
If stearin were composed of stearic acid and glycerin alone, its
constitution would be, according to the analysis of Liebig and
Pelouse, * modified by the subsequent investigations of Redten-
bacher and Verrentrapp, f
2 atoms stearic acid, . C136 H132 O10 = 128-5
1 atom glycerin, . . C6 H7 O5 = 10-375
2 atoms water, . H2 O2 = 2-25
C142 H141 O17 = 141-125
But it is probable that margaric acid, and also oleic acid, &c. are
very common ingredients in most varieties of stearin.
Margaric acid was first described by Chevreul in 1813, under
the name of margarin. In 1816 he gave it the name of marga-
ric acid. But it was not till 1820 that he was able to distin-
guish with precision margaric acid from stearic acid. The mode
of obtaining margaric acid employed by Chevreul has been de-
tailed in the Chemistry of Inorgaric Bodies, (Vol. ii. p. 125.)
Dr Redtenbacher first ascertained that, when pure stearic acid
is distilled over into a receiver, it is converted into margaric acid.
So that the stearic acid from the ox by distillation becomes the
acid of human fat Besides margaric acid there was formed mar-
garon,and a light oily substance which Redtenbacher called (from
its composition) polymo-carburetted hydrogen.
Varrentrapp found that when ox's tallow, mutton suet, hog's
lard, or olive oil were subjected to distillation, the solid products
obtained possessed the characters of margaric acid. They were
freed from the liquid products of the distillation by pressure, and
afterwards purified by repeated solutions in alcohol and crystal-
lizations, and finally they were saponified by soda, and precipi-
tated by means of muriatic acid. The distilled product contain-
ed also margaron and an oily carbohydrogen.
* Ann. de Chim. et de Phys. Ixiii. 148.
f Annalen der Pharm. xxxv. 46.
FAT OF COCHINEAL INSECT. 145
M. Bromeis found that when nitric acid is digested on stearic
acid, a violent action takes place, which becomes gradually more
moderate, and at last nearly ceases. The stearic acid after this
action becomes clear and liquid, and forms a tallowy, solid mat-
ter, which melts at 95° or 113°, according to the duration of the
process. This tallowy matter is margaric acid, mixed with a
product proceeding from the oleic acid present, which is easily
saponified by potash. It then assumes a blood-red colour, and
retains that colour after separation by an acid. The tallowy
mass separated from this body was freed from nitric acid by boil-
ing it in water. It was then dissolved in hot alcohol, and allowed
to cool. The margaric acid was deposited in crystals. It was
purified by repeated solutions in alcohol, by saponification and
precipitation by an acid.
Margaric acid resembles stearic acid very closely ; but it
melts at 140°, according to Chevreul, or 141°, according to
Bromeis ; while stearic acid requires for fusion the temperature
of 158° or 160°.
The constitution of this acid, and its analogy to stearic acid,
have been already pointed out. The common base is C34 H33.
Margaric acid is C34 H33 4. O3 = 32-625
Stearic acid, . 2 (C34 H33) + O5 = 64-25
Margaric acid, in its hydrous state, contains only 1 atom
water, while stearic contains 2. Hence the former combines
with only 1 atom of base, while the latter combines with 2. We
might also represent the constitution of these acids thus :
Margaric acid, C34 H33 + O3 = 32-625
Stearic acid, C34 H33 4. O24 = 32-125
According to that view of their constitution, both, in the hy-
drous state would contain 1 atom of water, and both would
combine with 1 atom of base.
CHAPTER IV.
-OF OILY OXIDES NOT SAPONIFIABLE.
THE oily bodies from the animal kingdom not capable of
being converted into soap are not numerous, and have been but
K
146 OILY OXIDES NOT SAPONIFIABLE.
imperfectly examined. The most important of them are Mar-
garon, Ethal, and Cholesterin, of which an account will be given
in the following sections.
SECTION I. — OF MARGARON.
This substance was discovered by M. Bussy in 1833.* He
obtained it by distilling a mixture of four parts of margaric acid
and one part of quicklime. A detailed account of it has been
given in the Chemistry of Vegetable Substances, (p. 120.) It
has been examined since with great accuracy by Messrs Redten-
bacher and Varrentrapp. M. Redtenbacher found that it con-
stituted one of the substances formed when stearic acid is sub-
jected to distillation.f Varrentrapp repeated the experiments of
Bussy, and purified the margaron first by digestion in potash,
and then by repeated solutions in ether and crystallizations.:]:
It is a white, pearly, scaly, crystallized substance, melting ac-
cording to Redtenbacher, at 170°.5, according to Varrentrapp
at 169°, according to Bussy at 170°. These slight differences pro-
bably are owing to errors in the thermometers used.
Margaron was analyzed by Bussy, Redtenbacher, and Varren-
trapp. The result obtained was as follows :
Bussy. Redtenbacher. Varreritrapp. Mean.
Carbon, . 82-22 82-483 81-62 82-108
Hydrogen, 13-51 13-863 13-80 13-724
Oxygen, . 4-27 3-653 4-58 4-168
100-00 100-000 100-00 100-000
These results approach each other very closely. As margaron
neither combines with acids nor bases ; and as it cannot be dis-
tilled over without decomposition, we cannot ascertain its atomic
weight But, if from the formula for hydrous margaric acid we
subtract an atom of carbonic acid and an atom of water, the re-
mainder will agree with the preceding analysis of margaron.
Hydrated margaric acid is . C34 H34 O4
Subtract 1 atom carbonic acid, C O2
And 1 atom water, . . HO
Remain, C33 H33 O
* Ann. de China, et de Phys. liii. 398.
f Annalen der Pharm. xxxv. 57. \ Ibid. p. 80.
ETHAL. 147
Now 33 atoms carbon, = 24*75 giving per cent 82-84
33 atoms hydrogen, — 4*125 ... 13*81
1 atom oxygen, = 1*00 -„. 3*35
29-875 100-00
This accords sufficiently with the mean of the preceding ana-
lyses to render it probable that margaron is formed by abstract-
ing an atom of carbonic acid and an atom of water from hydrous
margaric acid ; and if this be so, then the constitution of marga-
ron is C33 H33 O = 29-875.
SECTION IL OF ETHAL.
This oily-looking substance was discovered by Chevreui in
1818. He obtained it from the solid part of purified spermaceti,
to which he gave the name of cetin. It was saponified and the
soap decomposed by tartaric or phosphoric acid. The fatty mat-
ter which separates is a mixture of ethal with margaric and oleic
acids. These acids are combined with barytes and the excess of
barytes removed by boiling water. The whole is now digested
in cold but very strong alcohol, which dissolves the ethal toge-
ther with some margarate and oleate of barytes. When the al-
cohol is distilled off and the residue treated with absolute alcohol
or ether, the ethal only is dissolved, and may be obtained pure
by distilling off the solvent.
The properties of ethal, as determined by Chevreui, have been
already detailed in the Chemistry of Inorganic Bodies, (Vol. ii.
p. 332.)
In the Chemistry of Vegetable Bodies, (p. 321,) the subse-
quent analysis of ethal by Dumas and Peligot has been given.
They obtained,
Carbon, . 79.2
Hydrogen, . 14-2
Oxygen, . 6*6
100*0
They consider its constitution to be,
16 atoms carbon, — 12 or per cent. 79*34
17 atoms hydrogen, = 2*125 ... 14*05
1 atom oxygen, =1 ... 6*61
15*125 100*00
148 OILY OXIDES NOT SAPONIFIABLE.
which obviously agrees very well with the analysis. These
atomic numbers may be resolved into 4 (C4 H4) -f H O.
Now, when ethal is mixed with dry phosphoric acid in powder
and distilled, the acid retains an atom of water and a volatile
oily body passes over, composed of,
Carbon, . 86 = 16 atoms— 12 or per cent. 85-71
Hydrogen, 14 =16 atoms = 2 ... 14-29
100 14 100-00
Now the specific gravity of this liquid was found by them to
be 7-846. But the specific gravity of
16 volumes carbon, = 6-6666
16 volumes hydrogen, = 1-1111
7-7777
agreeing well with the specific gravity found. It appears from
this that the volatile oily body thus obtained from ethal is a com-
pound of sixteen volumes carbon and sixteen volumes hydrogen
condensed into one volume. To this oily body Dumas and Peli-
got have given the name of cetene,
SECTION HI. OF CETENE.
This substance has been described in the Chemistry of Vege-
table Bodies, (p. 322), to which the reader is referred.
There is every reason for believing that the oily liquid which
M. Redtenbacher obtained along with margaron and margaric
acid, when he distilled stearic acid, is identical with the cetene of
Dumas and Peligot. He found it composed of
Carbon, . 83*92
Hydrogen, . 14-1
which approaches the result of Dumas and Peligot. The dif-
ference was doubtless owing to the presence of a little margaron,
from which it was very difficult to free it.
SECTION TV. OF CASTORIN.
Castor is a well known substance, which is obtained from the
beaver. In each of the inguinal regions of that animal there are
two bags, a large and a small. The large one contains the true
castor ; the small one a substance which has some resemblance
to it, but which is in much less estimation.
CASTORIN. 149
Castor has a yellow colour, and when newly taken from the
animal it is nearly fluid, but, by exposure to the atmosphere, it
gradually hardens, becomes darker coloured, and assumes a resi-
nous appearance. Its taste is bitter and acrid, and its smell strong
and aromatic. In water it softens and tinges the liquid of a pale
yellow colour. The solution contains an alkali.
Castor was examined by Bouillon La Grange,* by Bizio,f and
by Brandes,! and by various other chemists. Bizio first distin-
guished a substance which he extracted from it by the name of
castorin. It had been already noticed by Fourcroy, Barneveld,
and Bohn ; but considered by them as adipocirc. It may be ex-
tracted from castor by the following process :
Boil castor in six times its weight of alcohol of the specific gra-
vity 0-85 ; filter and leave the liquid in an open glass till it is
reduced to one-half by evaporation ; draw off the liquid portion
from the castorin deposited, and wash this last with cold alcohol,
which partly removes the brown-coloured resinous matter. To
remove this matter completely, digest the castorin with an aque-
ous solution of ammonia, potash, or soda ; or treat its alcoholic
solution with animal charcoal. Such is the process employed by
Bizio.
Brande's process is somewhat different. He boiled castor with
alcohol, and filtered it hot. On cooling, it deposited a little fatty
matter. The alcoholic solution was then put into a retort, and
the greatest part of the alcohol distilled off. The liquid portion
in the retort was now separated from the castorin deposited.
This last substance was purified by washing it in cold alcohol.
Castorin is white, and crystallizes from its solutions in fine four-
sided transparent needles collected together in groups. It has
a slight smell of castor, and a peculiar metallic taste. It does
not alter vegetable colours. It is light and easily reduced to
powder. When put into boiling water, it melts into an oil, which
swims on the surface of the liquid, and which, after becoming so-
lid on cooling, remains transparent. When boiled with water
in a retort, it goes over in small quantities with the liquid, which
is at first limpid ; but after a certain time, deposites castorin.
When heated per se in a retort, it melts, boils, and an orange-
* Jour, de Phys. xlii. f Brugn. Giorn. xvii. 174-
Br. Arch. xvi. 281.
150 OILY OXIDES NOT SAPONIFIABLE.
yellow oil distils over, which, on cooling, constitutes a soft mat-
ter, having a resinous aspect.
Castorin is inflammable, and hums without smoke or smell,
leaving a quantity of charcoal hehind it. It is insoluble in cold
water ; boiling water dissolves a small quantity, which in a few
days is deposited in crystals. It dissolves with difficulty in alco-
hol, but the stronger that liquid is, the more of it does it dissolve-
Alcohol of 0.860 dissolves only j^th of its weight of castorin at
the boiling temperature. It is more soluble in ether. The vo-
latile oils while cold do not dissolve it. But oil of turpentine
dissolves it with the assistance of heat, and becomes muddy on
cooling. It may be melted with the fat oils.
Concentrated sulphuric acid dissolves it readily. The solution
is yellow, and water throws down the castorin of a yellow colour.
Diluted sulphuric acid dissolves it when assisted by heat. The
castorin is precipitated when the solution cools, or when the acid
is saturated with ammonia. Cold nitric acid does not dissolve it ;
but this acid dissolves it while boiling hot, and the solution has
a yellow colour. It becomes muddy on cooling, and the casto-
rin is precipitated by the addition of water. When nitric acid is
made to act long on castorin, it converts it into castoric acid.
Boiling acetic acid dissolves castorin abundantly ; when the
solution is concentrated by evaporation, the castorin is deposited
in crystals. The dilute alkaline leys dissolve a little of it when
assisted by heat, and on cooling the castorin is deposited unalter-
ed. Concentrated solution of caustic potash dissolves it at a boil-
ing temperature, and when the ley is diluted with water, the cas-
torin precipitates unaltered.
SECTION V. OF AMBREIN.
The substance called ambergris is found floating on the sea
near the coasts of India, Africa, and Brazil, usually in small
pieces, but sometimes in masses of 50 or 100 Ibs. weight. Va-
rious opinions have been entertained respecting its origin. Some
affirmed that it was the concrete juice of a tree ;* others thought
it a bitumen ; others altered bees-wax. f But it is now consider-
ed as pretty well established that it is a concretion formed in the
stomach or intestines of the Physeter macrocephalus, or spermaceti
whale. This fact was first ascertained by the fishermen of New
* Phil. Trans. 1673, viii. 6113. "f See Pomet on Drugs, ii. 4&
3
AMBREIN.
England about the year 1720. They found about 20 Ibs. of am-
bergris in the intestines of one of these animals.* This account
was confirmed in 1783 by Dr Schwediawer,f and in 1791 by Mr
Champion. :f
Ambergris, when pure, is a light soft substance which floats in
water. Its specific gravity, as determined by Brisson, varies from
0-78 to 0*92. Its colour is ash-gray, with brownish-yellow and
white streaks. It has an agreeable smell, which improves by
keeping. It is insipid to the taste.
Ambergris was subjected to a chemical examination by Bouillon
Lagrange about the beginning of the present century ;§ by Bu-
cholz in 1810. || Pelletier and Caventou subjected it to a new
examination in 1820, 1F and showed that it consisted chiefly of a
peculiar fatty matter, which they distinguished by the name of
ambrein ; and in 1832 Pelletier subjected ambrein to a chemical
analysis.**
Ambrein may be obtained by digesting ambergris in hot alco-
hol of the specific gravity 0*827. The alcohol, on cooling, de-
posites the ambrein in very bulky and irregular crystals, which
still retain a considerable portion of alcohol. This may be got
rid of, by subjecting the ambrein to pressure between folds of
blotting-paper.
Ambrein thus purified is a white, brilliant, and insipid solid.
It has an agreeable smell, which may be driven off by keeping
the ambrein a long time in a state of fusion by means of a gentle
heat ; or by repeated solutions in alcohol and crystallizations.
According to Pelletier and Caventou, it melts, when heated,
to 86°, and softens at 77°. When heated on platinum foil, it
melts, smokes, and is volatilized, without leaving any residue. It
is insoluble in water, but dissolves readily in alcohol and ether.
When distilled per se in a retort, it becomes brown, but passes
over into the receiver without having suffered any notable alte-
ration, leaving in the retort a little charcoal. It dissolves also
in volatile and fixed oils. Nitric acid converts it into a peculiar
acid,, which has been already described in a preceding chapter of
this volume under the name of ambreic acid.
* Phil. Trans. 1724, xxxvii. 193, 256. f Ibid. 1783, p. 226.
\ Phil. Trans. 1791, p. 43. § Ann. de Chim. xlvii. 6&
|| Ann. de Chim. Ixxiii. 95. J Jour, de Pharm. vi. 49*
•* Ann. de Chim. et de Phys. li. 187.
OILY OXIDES NOT SAPONIFIABLE.
Ambrein, like cholesterin, is incapable of being converted
into soap, showing clearly that it does not possess acid properties.
Pelletier subjected ambrein to an ultimate analysis by means
of oxide of copper, and obtained,
Carbon, . 83-37
Hydrogen, . 13-32
Oxygen, . 3-31
100-00
As we do not know any substance with which ambrein com-
bines in definite proportions, we cannot determine its atomic
weight. This puts it out of our power to state the number of
atoms which enter into its composition. But the smallest num-
ber of atoms which correspond with the preceding analysis is the
following :
33 atoms carbon, = 24-75 or per cent. 83-20
32 atoms hydrogen, = 4. ... 13-44
1 atom oxygen, = 1* ... 3-36
29-75 100-00
This would make the atomic weight 29*75. It is obvious, from
the quantity of oxygen, that the number of atoms cannot be
fewer than here stated ; but, for any thing that appears, they
may be double or triple that quantity.
SECTION VI. OF CHOLESTERIN.
This substance was noticed by Gren in 1789, as constitut-
ing the greatest part of a gall-stone which he subjected to a
chemical analysis.* He gave it the name of a waxy-looking sub-
stance. Chevreul afterwards examined its properties more in
detail, and stated that he had discovered it as one of the consti-
tuents of oils. He made its distinctive characters known in a
paper which was read to the French Institute in the year 1814.
The same subject was again taken up by him in his Recherches
Chimiques sur les Corps Gras, published in 1823,f In that work,
Chevreul assures us, that cholesterin was first obtained by Poul-
letier de la Salle by treating gall-stones with boiling alcohol. I
find this statement verified by Macquer, who, in the second edi-
* Beytr. z. d. Chem. Annalen, iv. 19. f Sur les Corps Gras, p. 155.
CHOLESTERIN. 153
tion of his Dictionary of Chemistry, published in 1778, notices
cholesterin as a singular substance, and gives some of its proper-
ties, and informs us, that it was discovered by the author of the
French translation of the London Pharmacopoeia.* This was
Poulletier de la Salle. In 1834, Couerbe showed that it exists
also as a constituent of the brain ; though between that in the
brain and in human gall-stones there are some differences which
we shall point out at the end of this section.
Cholesterin may be obtained in a state of great purity by di-
gesting human gall-stones in boiling alcohol, drawing off the
clear solution, and leaving it to cool. The cholesterin is depo-
sited in beautiful crystalline plates. It may be obtained from
bile by the following process :
Evaporate the bile to the consistence of a thick extract ; agi-
tate this extract several times in succession with ether, till that
liquid ceases to extract any thing from it. Mix all these ethe-
rial liquids, and draw off the greatest part of the ether by distil-
lation. The residue, on cooling, deposites crystals of cholesterin,
mixed with some oleic acid. This may be got rid of either by
digesting the impure cholesterin with dilute caustic alkali, which
dissolves the oleic acid, and leaves the cholesterin pure ; or, by
dissolving the impure crystals in boiling alcohol, as the solution
cools, the cholesterin is deposited in crystals, and in a state of
purity.
Cholesterin crystallizes in beautiful white plates, having a
pearly lustre. It has some resemblance to spermaceti, but is
more beautiful. It has neither taste nor smell. It is lighter than
water, and when heated to 278°, it melts into a liquid as colour-
less as water. On cooling, it concretes into a foliated crystalline
mass, translucent, and capable of being reduced to powder. But
the powder attaches itself strongly to every body with which it
comes in contact. When distilled per se in a retort, (air being
excluded,) it mostly passes over unaltered, and is deposited in
crystalline plates. But if air have free access, the cholesterin
undergoes decomposition, assumes a brown or yellow colour, and
a considerable quantity of empyreumatic oil is formed, which holds
a portion of cholesterin in solution. According to Kiihn,f if we
heat cholesterin in a glass-tube till a portion of it sublimes, and
* Macquer's Diet. i. 501. f Diss. de Cholesterine. Leipsik, 1828.
154 OILY OXIDES NOT SAPONIFIABLE,
then allow it to cool, the portion not sublimed remains in a
liquid state, even though cooled down to zero.
Cholesterin does not act on vegetable blues ; does not form a
soap with potash ; with sulphuric acid it strikes an orange-red
colour.*
The crystals of cholesterin deposited from alcohol contain
about 5 '15 per cent, of water of crystallization, which may be
driven off by heat. When heated on platinum foil, it catches
fire and burns like wax. It is very little soluble in water. Cold
alcohol dissolves very little ; but the stronger the alcohol, the
more it dissolves. According to Chevreul, boiling alcohol of
0*84 dissolves the ninth part of its weight of cholesterin ; while
boiling alcohol of 0-816 dissolves j.£j. Pyroxylic spirit behaves
almost exactly as alcohol. But a considerable portion of the
cholesterin is retained in solution after the spirit cools. Ether,
at 32°, dissolves -f1^, at 59°, 7!7, and at a boiling temperature,
2.Js of its weight of cholesterin. It is very slightly soluble in oil
of turpentine, but may be united to the fixed oils by fusion.
It does not dissolve in sulphuric acid, but gives the liquid a
yellow colour. It then becomes viscid, and swims on the sur-
face of the acid in the form of a pitchy mass, while at the same
time sulphurous acid is evolved. The decomposition goes on still
more rapidly when the acid is heated. Nitric acid converts it
into cholesteric acid and artificial tannin.
Cholesterin was subjected to an ultimate analysis by Chevreulf
and by Couerbe,J and by Pelletier,§ who found it composed of,
Chevreul. Couerbe. Pelletier.
Carbon, 85-095 84-b95 83.37
Hydrogen, - 11-880 12-099 13-32
Oxygen, - 3-025 3-006 3-31
100-000 100-000 100-00
The smallest number of atoms which corresponds with thi&
analysis is the following :
38 atoms carbon, — 28-5 or per cent. 85-07
32 atoms hydrogen, = 4'0 ... 11*94
1 atom oxygen, =1-0 ... 2-99
33-5 100.00
* Chevreul; Jour, de Pbysiologie, iv. 257. f Surles Corps Gras, p. 15£
| Ann. de Chim. et de Phys. Ivi. 183. § Ibid. li. 188.
SEROL1N. 155
According to this statement, the atomic weight of cholesterin is
33*5. We have seen that the crystals are composed of,
Cholesterin, 94-85 or 67
Water, 5-15 or 3.636
100-00
Now 3-636 is very nearly the weight of 3 atoms of water-
Hence it is not unlikely that the true atomic weight of choles-
terin is 67, and that its constitution is C76 H64 O2 = 67.
M. Couerbe found cholesterin in the human brain* and doubt-
less it may be extracted from the brains of most of the Mamma-
lia. The brain was digested four times successively in ether,
till every thing soluble in that liquid was taken up. The resi-
due was treated with boiling alcohol till every thing soluble in
that liquid was abstracted. The alcohol on cooling deposited a
white matter. This white matter being digested in cold ether
a quantity of cholesterin is dissolved, which separates in crystals
when the ether is evaporated.
The quantity of cholesterin in the brain is considerable. It
possesses the same characters as that from biliary calculi, except-
ing that it does not melt till heated to 293°. It remains in a
liquid state till cooled down to 239°, provided it be quite still,
but the least agitation, that for instance caused by touching it
with a hair, makes it immediately congeal into a crystalline so-
lid. Couerbe found the ultimate constituents of cholesterin from
biliary calculi, and from the brain the same. The cholesterin
from the brain differs from that of biliary calculi in one remark-
able circumstance. It dissolves better in alcohol, and furnishes
a solution as it were unctuous. When filtered and allowed to
cool it does not deposite crystals immediately. The crystalli-
zation begins after an interval of some time. The crystals are
plates, often several inches long and beautiful, provided no cere-
brote be present.
SECTION VII. — OF SEROLIN.
This substance was detected in the serum of blood by M.
Boudet in 1833.f He obtained it by setting aside a hot alco-
holic decoction of dried serum. As the alcohol cooled, a white mat-
ter, having a slightly pearly lustre, was deposited. It was sero-
lin.
* Ann. de Chim. et de Phys. Ivi. 180. f Jour, de Pharm. xix. 29&
156 OILY OXIDES NOT SAPONIFIABLE.
It is composed of very minute white filaments, distinguishable
only under the microscope. It melts, when heated, to 97°, has no
acid reaction, and, like cholesterin, becomes red when placed in
contact with concentrated sulphuric acid. It does not form an
emulsion with cold water, and when the liquid is heated, the se-
rolin floats on the surface under the form of a colourless oil.
Sulphuric ether dissolves it readily even without the assistance of
heat. Alcohol of 0-842 dissolves only a minute trace of it when
boiling-hot, and it is not in the least soluble in cold alcohol. It
was digested for six hours in potash ley, without being dissolved.
Hence, like cholesterin, it seems incapable of forming soap.
Acetic and muriatic acids do not act upon it whether they be
cold or hot Though long heated in nitric acid, it is not dis-
solved ; but it becomes soluble in potash ley, which it colours
brown.
When distilled, it gives out a very characteristic odour, emits
ammoniacal vapour, and is partly volatilized.
SECTION VIII. OF CANTHARIDIN.
This name has been given to the substance in cantharides or
Spanish flies, (Meloe vesicatorius, Lytta vesicatoria, &c.) which
occasions a blister when applied to the skin. Its properties were
examined by Robiquet in 1810,* and more lately by L. Gmelin.
Robiquet obtained it by the following process :
Cantharides were boiled in water till every thing soluble in that
liquid was taken up. The aqueous solution was concentrated to
the consistence of a thick syrup, which was repeatedly boiled in
alcohol, till that liquid ceased to act upon it The alcoholic so-
lution was evaporated to dryness in a gentle heat. The residue
was put into a phial with ether, and agitated for a considerable
time. After some hours the ether assumed a yellow colour. It
was then decanted off", and left to spontaneous evaporation in an
open dish. As the ether evaporated, small crystalline plates
were deposited mixed with a yellow matter. Alcohol took up
the yellow matter, but left the plates. Being dried between folds
of blotting-paper, these plates constituted cantharidin in a state
of considerable purity.
Thus obtained, it is in small crystalline plates, resembling mica,
which melt, when heated, into a yellow, oleaginous liquid. On
cooling, it concretes into a crystalline solid. When heated more
* Ann. de Chim. Ixxvi. 302.
CANTHARIDIN. 157
strongly it is volatilized in a white smoke, which condenses into
a white crystalline sublimate. The smallest particle of this mat-
ter is sufficient to raise a blister on the skin. Even the eyes, the
nose, and the organs of respiration cannot be exposed to the va-
pour of it without hazard.
Cantharidin is neutral, neither reacting as an acid or base.
It is insoluble in water, almost insoluble in cold alcohol, but so-
luble in that liquid when boiling-hot. It is very soluble in ether
and in the fat oils. It was analyzed by M. Regnault ;* 1060
parts gave 2293 of carbonic acid, and 576 of water. Hence the
constituents are
Carbon, 59.00
Hydrogen, 6-04
Oxygen, 34-96
100-00
He represents the constitution of cantharidin by the formula
C10 H6 O4. If we calculate from this, we get
10 atoms carbon — 7-5 or per cent, of 61-21
6 atoms hydrogen = 0-75 ... 6-13
4 atoms oxygen = 4- ... 32'66
12-25 100
There is always a deficiency of carbon in the ordinary analyses
by Liebig's apparatus. This occasions a corresponding increase
in the oxygen.
CLASS IV.
OF ANIMAL COLOURING MATTERS.
THESE have hitherto been very imperfectly investigated. On-
ly a very few of the great number of colouring matters which
occur in 'the animal kingdom can be noticed here ; because they
have not hitherto attracted the attention of chemists.
* Ann der Pharm. xxix. 314.
158 ANIMAL COLOURING MATTERS.
CHAPTER I.
OF CARMIN.
Cochineal ( Coccus cacti) is an insect which inhabits different
species of cactus* as the coccinellifer, opuntia, turia, &c. These
plants are cultivated in Mexico and some other parts of Ameri-
ca for the nourishment of the insect.
The females are stationary upon the plant. They are collect-
ed, killed by heat, and then dried. They occur in commerce in
the state of small dark-brown grains ; and are employed in dye-
ing scarlet, and in making a beautiful red lake used as a colour
by painters.
Cochineal was first examined by Dr John 1813.f He made
a chemical analysis of the insect, extracted the colouring matter,
and described its characters under the name of cochenillin. In
1818, an elaborate examination of cochineal and of its colouring
matter under the name of carmin, was published by Pelletier
and Caventou,J and in 1832 the subject was farther prosecuted
by Pelletier, who made a chemical analysis of carmin and de-
termined its constitution.§
Carmin may be obtained from the cochineal insect in the fol-
lowing manner : Digest the cochineal insect in alcohol as long
as it communicates a red colour to that liquid. When these so-
lutions are left to spontaneous evaporation they let fall a crystal-
line matter of a fine red colour. This is carmin, but not in a
state of purity. Dissolve these crystals in strong alcohol, and
mix the solution with its own bulk of ether. The liquid becomes
muddy, and after an interval of some days the carmin is deposit-
ed at the bottom of the vessel, forming a beautiful purplish red
crust
Carmin thus obtained has a fine purple red colour. It ad-
heres strongly to the sides of J:he vessel in which it is deposited
It has a granular appearance, as if it were composed of crystals.
* A detailed account of this insect, of the wild cactus, and of the mode of
rearing these insects, and preparing them for dye stuff, may be found in Ban-
croft's Researches concerning the Philosophy of Permanent Colours, i. 236.
•f Chemische Untersuchungen, iii. 210.
\ Ann. de Chira. et de Phys. viii. 250. § Ibid. li. 194,
CARMIN. 159
It is not altered by exposure to the air, nor does it absorb any
sensible quantity of moisture. When heated to 122° it melts.
If the heat be increased it swells up, and is decomposed, yielding
carburetted hydrogen, a great deal of oil and a little water, hav-
ing a slightly acid taste. It gives no trace of ammonia ; yet,
according to the analysis of Pelletier and Caventou, azote consti-
tutes one of its constituents, though its quantity is small.
Carmin is very soluble in water. The solution may be con-
centrated by evaporation to the consistence of a syrup ; but no
crystals are deposited. The aqueous solution has a fine carmine
red colour. A very small quantity of carmin communicates its
colour to a great deal of water. It is soluble also in alcohol ;
but the stronger the alcohol the worse a solvent it becomes. It
is insoluble in ether. The weak acids dissolve it, probably in con-
sequence of the great quantity of water which they contain. No
acid precipitates it when pure ; but they almost all throw it down
when it is in combination with the peculiar animal matter of the
cochineal. All the acids, however, induce a sensible change upon
the aqueous solution of carmin. They cause it, in the first place,
to assume a lively red colour, which gradually acquires a yellow-
ish tinge, and at last becomes quite yellow. When the acids are
not very concentrated, the carmin is not altered in its nature, for
when we saturate the acid, the solution assumes its original co-
lour.
Concentrated sulphuric acid destroys and chars carmin. Mu-
riatic acid decomposes it without charring, and converts it into
a bitter tasted substance, which has no resemblance to the origi-
nal colouring matter. Nitric acid decomposes it with still greater
rapidity. Some needle-form crystals are formed similar in ap-
pearance to oxalic acid ; but they do not precipitate lime-water,
even when mixed with ammonia.
Chlorine acts with energy on carmin, giving it at first a yel-
low colour, and afterwards destroying the colour altogether^
Chlorine causes no precipitation in an aqueous solution of carmin^
provided the solution be pure. It is therefore a useful reagent
to enable us to discover the presence of an animal matter in the
solution of carmin. Iodine acts precisely as chlorine, but with
less rapidity.
The alkalies, when poured into a solution of carmin, give it a
violet colour. If the alkali be saturated immediately, the origi-
160 ANIMAL COLOURING MATTERS.
nal colour of the solution reappears, but if the action of the al-
kali be prolonged, or if it be increased by the application of heat,
the violet colour is destroyed, and the liquid becomes first red
and then yellow.
Lime-water occasions a violet-coloured precipitate when dropt
into the aqueous solution of carmin. Barytes and strontian cause
no precipitate, but produce the same change of colour as the alkalies.
Alumina has a very strong affinity for carmin. When newly
precipitated alumina is put into an aqueous solution of carmin,
the liquid is deprived of its colour, and the alumina converted
into a beautiful lake. If a few drops of acid be added to the
aqueous solution before introducing the alumina, the lake ob-
tained has a fine red colour as before, but it becomes violet on
the application of the least heat. The same effect is produced if
we add to the liquid a few grains of an aluminous salt.
Most of the saline solutions alter the colour of the aqueous so-
lution of carmin, but few of them are capable of throwing down
a precipitate from it. Solutions of gold merely/liter the colour ;
nitrate of silver occasions no change whatever ; the soluble salts
of lead render the colour violet ; and acetate of lead occasions
an abundant violet precipitate. By decomposing this precipitate
by means of a current of sulphuretted hydrogen, we may obtain
the carmin dissolved in water in a state of purity. Protonitrate
of mercury throws down a violet precipitate. Pernitrate of mer-
cury does not act so powerfully, and the colour of the precipitate
is scarlet. Corrosive sublimate produces no effect whatever.
Neither salts of copper nor of iron produce any precipitate ;
but the former change the colour of the liquid to violet, the lat-
ter to brown. Protochloride of tin throws down a copious violet
precipitate ; while the perchloride changes the colour to scarlet,
but precipitates nothing. When gelatinous alumina is added to
the mixture, we obtain a fine red precipitate, which is not altered
by boiling. None of the aluminous salts occasion a precipitate ;
but they change the colour to carmin. The salts of potash, so-
da, and ammonia, change the colour of the liquid to carmin red.
From the action of the different salts on carmin, Pelletier and
Caventou have drawn as a conclusion, that the metals suscepti-
ble of different degrees of oxydizement act like acids on the co-
louring matter when at a maximum of oxidation, but like alkalies
when at a minimum or medium degree ; and that this alkaline
SERICIN.
161
influence may be exercised in the midst of an acid when the oxides
in question are capable of forming an insoluble precipitate with
the carmin.
Tannin and astringent principles in general do not precipitate
carmin.
Pelletier and Caventou analyzed carmin in 1818 by means of
black oxide of copper, without obtaining any azotic gas. But in
a new analysis published by them in 1832, they state the amount
of azote in carmin to be 3-56 per cent. But no particulars re-
specting the mode of the analysis or the substances obtained are
stated. The bare centesimal result is given. So that we have
no means of judging the degree of accuracy which was obtained.
The following table exhibits their analysis :
Carbon, . 49-33 or 32 atoms = 24 or per cent. 49-00
Hydrogen, . 6-66 or 24 atoms = 3 ... 6-63
Azote, . 3-56 or 1 atom = 1-75 ... 3-57
Oxygen, . 40-45 or 20 atoms = 20-00 ... 40-80
100-00 48*75 100-
The carmin subjected to this analysis was previously dried in
vacuo by a heat not specified. Pelletier and Caventou think it
not unlikely that it still retained a portion of water.
In the year 1819, M. Lassaigne examined another species of
Coccus, the Coccus ilicis, or kermes, which is common in the south
of Europe, and which had been employed as a red dye before the
introduction of cochineal after the discovery of America. From
his experiments it appears that kermes in its nature bears a close
resemblance to cochineal, and that it also contains a considerable
proportion of carmin, identical in its nature with that from the
Coccus cacti.*
CHAPTER II.
OF SERICIN, OR THE COLOURING MATTER OF SILK.
IT is universally known that raw silk is a very fine thread spun
by the silk-worm (Bombyx mori,) and in which it envelopes itself
while in the chrysalis state. In China there is a silk-worm which
* Jour, de Pharmacie, viii. 435.
162
ANIMAL COLOURING MATTERS.
spins a thread of the most dazzling whiteness. But the colour
of raw silk from India, Italy, and France is yellow. Some ex-
periments on this colouring matter were made by Hoard in 1807.*
According to him it is a resinous substance, almost solid at the
temperature of 59°, but quite fluid at 86°. Its colour is red-
dish-brown while in lumps, but a fine greenish-yellow when in a
state of division. Silk contains from ^V^h to ^5th part of it. Its
smell is strong, proceeding from a volatile oil which it contains.
Light bleaches it completely in a few days, when concentrated
solutions of it are exposed to its action. It is insoluble in water,
but very soluble in alcohol. The fixed alkaline leys, especially
ammonia, dissolve a little of it while cold, and the action is not
much increased by heat ; while soap, which has little action while
cold, is rather a powerful solvent of it at the temperature of boil-
ing water. Concentrated sulphuric and muriatic acids char it
immediately. Sulphurous acid partially bleaches it Chlorine
bleaches it instantly, converting it into a solid matter like wax.
According to Mulder f the colouring matter of yellow silk has
a fine red colour. He obtained it in the following manner : —
The alcoholic tincture of raw yellow silk is concentrated by dis-
tillation to a small quantity ; flocks of cerin are deposited. The
residual liquid being now evaporated, the colouring matter re-
mains mixed with fat and resin. From these substances it is
freed by digestion in a solution of caustic potash. This solution
must not be too strong, otherwise the fine red of the colouring
matter is rendered dark.
This colouring matter is insoluble in water ; but very soluble
in alcohol, ether, fat and volatile oils. When placed in contact
with chlorine or sulphurous acid, it becomes light yellow ; indeed,
almost white.
The quantity of colouring matter in raw yellow silk is, accord-
ing to Mulder, about ^ggth part of the silk.
Ann, de Chimie, Ixv. 61. t Poggendorf's Annalen, xxxvii. 610.
CANCRTN. 163
CHAPTER III.
OF CANCRIN, OR THE COLOURING MATTER OF CRABS.
IT is well known that the crusts which cover the different spe-
cies of Cancer, as the gammarus (or lobster), the astacus (or craw-
jisti), &c. are black, or nearly so, but become of a fine red co-
lour when boiled. It is evident from this that they contain a
peculiar colouring matter.
Dr John made a chemical examination of the crust of the Can-
cer astacus in 1811. * He notices some of the characters of the
colouring matter ; but does not seem to have made any attempt
to obtain it in a separate state. Lassaigne, in 1820, succeeded in
isolating it, and made some experiments on it. f The investiga-
tion was carried somewhat farther in 1821 by M. Macaire, who
found two different colouring matters in these crusts \
The colouring matter of these crusts is analogous to suet. In
the natural state its colour is dark bluish-green. When heated
to 158° it becomes red, and then has some resemblance to the
beak of the duck. It is contained partly in the shell, and partly
in the greenish membrane immediately under the shell. Some
of it is also to be found in another membrane situated immedi-
ately below the green one, and from which it may be separated
by maceration in water. But in this second membrane, the co-
louring matter is already red. Lassaigne obtained the colouring
matter by digesting the clean shell in alcohol till that liquid
ceased to extract any thing more. The alcoholic solution is red.
When it is evaporated to dryness there remains a solid red mat-
ter, similar to suet, which, after having been washed in hot water,
may be kept without undergoing any alteration. It is insoluble
in water ; but very soluble in alcohol and ether. The alcoholic
solution has a scarlet colour, and is not precipitated by water.
It is soluble by the assistance of heat in melted tallow, and in
the vplatile oils. It is stated by Macaire not to be soluble in the
fixed oils.
It dissolves readily in dilute sulphuric acid, but is decomposed
* Chemische Untersuchungen, ii. 49.
•f- Jour de Pharmacie, vi. 174
\ Bibl. Univer., July 1821, or Schweigger's Journal, xxxiii. 257-
164 ANIMAL COLOURING MATTERS.
by that acid when in a concentrated state. Nitric acid converts
it into a bitter tasted matter. When the alcoholic solution is
mixed with sulphuric or nitric acid, it becomes green, and the
red colour is not restored by saturating the acid with an alkali.
Caustic potash dissolves it, assuming a red colour. From this
solution it is precipitated by the acids, without having been aci-
dified. The alcoholic solution loses its colour when alum is ad-
ded to it. If we add ammonia we obtain the colouring matter
united to alumina. The alcoholic solution is precipitated by
acetate of lead. The compound of the colouring matter and
oxide of lead is violet. The salts of iron, tin, copper, and mer-
cury have no action on it.
The deep green shell of the cancri is reddened by acids, al-
kalies, by some salts, by putrefaction ; by the action of air and
oxygen, but it is not reddened by carbonic acid nor by hydro-
gen. Chlorine gas bleaches it. According to the analysis of
Goebel it is composed of,
Carbon, 68-18 or 16 atoms carbon = 12 or percent. 68.08
Hydrogen, 9-24 or 13 atoms hydrogen = 1-625 9-22
Oxygen, 22-58 or 4 atoms oxygen — 4- 22-70
100-00* 17-625 100-
CHAPTER IV.
OF PERISTERIN OR THE COLOURING MATTER OF PIGEON'S FEET,
THIS r "1 colouring matter was examined by Goebel, who fou ~ d
it analogous to that of the craw-fish. It is easily separated by
digesting the pigeon's foot in water. The external cuticle by
this process is easily separated, so that the red pigment is quite
exposed, and may be easily separated by a fine knife.
It is easily soluble in absolute ether and alcohol, forming a
fine carmine red solution. When the liquid is evaporated the
colouring matter remains as a fine shining red mass, having the
consistence of tallow. It is insoluble in water. On hot water it
swims in red drops ; but concretes into a solid mass when the li-
quid cools. It dissolves in caustic potash. The solution may be
* Scliweigger's Journ. xxxix, 429.
ANSERIN. 165
diluted with water, and the colouring matter is precipitated un-
altered by acids. Acetic acid does not dissolve it. Sulphuric
and nitric acids decompose it. It is soluble in volatile oils;
and all its solutions have a fine red colour.
Its taste and smell are weak and mouldy, somewhat similar to
that of fat It does not alter the colour of vegetable blues. Ac-
cording to the analysis of Goebel it is composed of,
Carbon, . 69-02
Hydrogen, 8 -74
Oxygen, . 22-24
100-00*
As we are ignorant of the atomic weight of this substance we
cannot deduce its constitution from this analysis. But the smal-
lest number of atoms of each constituent deducible from it are
the following :
4 atoms carbon, — 3- or per cent 68-58
3 atoms hydrogen, — 0-375 . 8-57
1 atom oxygen, = 1- . 22.85
4-375 100-00
CHAPTER V.
OF ANSERIN, OR THE COLOURING MATTER OF GOOSE FOOT.
THE pigment on the feet and bills of the goose has a yellow
colour, and possesses all the chemical characters of the colour-
ing matter of the craw-fish and pigeon's foot At the ordinary
temperature of the atmosphere it is liquid and resembles oil, but
at 45 £°, it assumes the consistence of tallow. Its constituents,
as determined by Goebel, are,
Carbon, . 65-53
Hydrogen, . 9.22
Oxygen, . 25.25
100-OOf
The atomic weight being unknown we cannot deduce the con-
* Schweigger's Journ. xxxix. 426. f Ibid, xxxix. 450.
166
ANIMAL COLOURING MATTERS.
stitution of the pigment from this analysis. But the smallest
number of atoms which corresponds with the preceding analy-
sis is the following :
10 atoms carbon, . — 7*5 or per cent. 64-52
9 atoms hydrogen, — 1-125 . 9-68
3 atoms oxygen, . = 3-000 . 25.80
11-625 100-00
CHAPTER VI.
COLOURING MATTER OF THE ANCIENT PURPLE DYE.
THE most celebrated and precious of all the ancient dyes was the
purple. The method of dyeing which was monopolized by the Ty-
rian dyers, who seem to have been acquainted with it at a very
early period. The dye stuff was a white^clammy liquor, obtain-
ed from a variety of univalve shells found on the coast of the
Mediterranean. Pliny divides these Shells into two genera, which
he distinguishes by the names of Buccinum and Purpura. * About
two drops of the liquid was obtained from each fish, by opening
a reservoir placed in the throat To avoid the trouble of ex-
tracting it from every individual fish, they were often bruised in
a mortar. The liquor when extracted was mixed with salt to
prevent putrefaction. It was then diluted with five or six times
its weight of water, and kept moderately hot in leaden or tin
vessels for the space of ten days, during which the liquor was of-
ten skimmed to separate impurities. After this the wool, pre-
viously washed, was immersed and kept therein for five hours. It
was then taken out, carded, and immersed again, and kept in the
liquid till all the colouring matter was extracted. Pliny informs
us that the Tyrians first dyed their wool in the liquor of the Pur-
pura and afterwards in that of the Buccinum.
Another mode of preserving the purple dye was by covering
it with honey. Plutarch, in his Life of Alexander the Great, in-
forms us, that there was found in the King of Persia's palace at
Susa, five thousand talents of the purple of Hermione, which,
though it had been laid up one hundred and ninety years, retain-
* Plinii, lib. ix. c. 36.
4
PURPLE DYE. 167
ed its first freshness and beauty. The reason assigned for this
is, that the purple wool was combed with honey and the white
with white oil.*
The wool thus dyed was so costly that, in the time of Au-
gustus, each pound of it sold for 1000 Roman denarii, (about
L. 36 Sterling).
The art of dyeing this colour came at last to be practised on-
ly by a few individuals, maintained by the emperors for that pur-
pose. It was interrupted about the beginning of the twelfth
century, and all knowledge of it was lost. But in the year 1683,
Mr Cole of Bristol, being told that a person at a sea-port in Ire-
land gained a living by marking linen with a red coloured dye
stuff, was induced to make inquiry into his mode of proceed-
ing. He found that the individual in question made use of a
white liquor in the head of the Buccinum lapillus of LinnaBus ;
a shell very common on our coasts.
Mr Cole procured this liquor from the fish, and stained linen
with it. When exposed to the light of the sun the stain be-
came first green, then blue, and finally a purple red.f
These experiments of Cole were afterwards repeated success-
fully by M. Jussieu, M. Reaumur, and M. Duhamel. They ob-
served the same succession of colours. And they mention also
a fetid smell like a mixture of garlic and assafoetida, given out
while it was changing its colours. This smell had been also no-
ticed by Cole. As no experiments on this curious liquid have
been made by modern chemists, we are still ignorant of its nature
and properties. I have mentioned it here merely to draw the
attention of such chemists as, living upon the sea-coast, may have
it in their power to procure the shell fish that yield it.
CLASS V.
OF ANIMAL AMIDES.
THE substances included under this name constitute a very
important portion of the materials of which animal bodies are
composed. They are still so imperfectly known that we do not
* Langhorne's Plutarch, ix, 373. f Phil. Trans, xv. 1278.
168 ANIMAL AMIDES.
know whether they ought to be placed among animal acids or
bases, or whether they are not rather indifferent substances. The
last supposition accords best with the present state of our know-
ledge. They have a strong analogy to the amides from the ve-
getable kingdom ; the account of which will be found in the
Chemistry of Vegetable Bodies, p. 590. For this reason they
have been placed together under that provisional denomination.
They may be arranged under the following heads :
I. Protein. II. Gelatin,
(1.) Albumen. (1.) Collin.
(2.) Albumen from silk. (2.) Chondrin.
(3.) Casein. (3.) Gelatin from silk.
(4.) Fibrin of blood. III. Hematosin
(5.) Fibrin of silk. IV. Spermatin.
(6.) Ricotin. V. Salivin.
VI. Pepsin.
VII. Pancreatin.
These will be the subject of the seven following chapters.
CHAPTER I.
OF PROTEIN.
THIS name was given by Mulder to a substance which consti-
tutes the bases of albumen, fibrin, flesh, casein, and probably of
other animal tissues.* To obtain it, albumen from eggs or blood
may be taken and digested in water, alcohol, and ether, till every
thing soluble in these liquids has been removed. It is then
treated with dilute muriatic acid, which removes the insoluble
earthy salts, especially phosphate of lime. It is then to be dis-
solved in a moderately strong alkaline ley, and the solution must
be heated to 122°, by which a little phosphate of potash and sul-
phuret of potassium are formed, originating from sulphur and
phosphorus existing in the albumen in an unoxydized state.
The protein thus treated is precipitated from its alkaline solu-
* So named from av*T«i/». I am first.
3
PROTEIN. 169
tion by acetic acid, added only to a very small excess, because
too much would again dissolve the protein. The gelatinous pre-
cipitate is collected on a filter, and washed till every trace of
acetate of potash is removed.
Protein thus purified constitutes gelatinous, translucent, grey-
ish flocks which, when dried, assume a yellowish colour, and be-
come hard and brittle, and easily pulverized. The powder is
amber yellow, destitute of smell and taste, absorbs moisture from
the atmosphere ; which it again loses when heated to 212°.
When heated, it undergoes decomposition before it melts. It
swells up, gives out empyreumatic oil, ammoniacal water, and
inflammable gas, and leaves a porous charcoal, which burns rea-
dily in the air without leaving any residue.
Protein sinks in water, and when left in that liquid, softens
and swells* and assumes the original appearance which it had be-
fore it was dried. It is insoluble in water, alcohol, ether, and
volatile oils. When boiled in water, it is partly dissolved, but
the process is so slow, that after sixty hours boiling, most of the
protein still remains unacted on. When the dissolved portion
is evaporated, the matter remaining is translucent and yellow,
and consists of two substances, one of which dissolves in alcohol^
and the other not.
Protein combines both with acids and bases. It dissolves in
all very dilute acids, and forms with them a kind of neutral com-
pound, which is insoluble or difficultly soluble when there is an
excess of acid present. Hence, if to a solution of protein sulphu-
ric, nitric, phosphoric, or muriatic acid be added, the protein pre-
cipitates in combination with the acid added. And when the ex-
cess of acid is washed away, the precipitate again dissolves.
Acetic acid and phosphoric acid constitute an exception, as they
dissolve protein even when added in excess. When treated with
them in a concentrated state, the protein first gelatinizes, and
then dissolves. From the solution in acetic acid protein is pre-
cipitated by prussiate of potash, by tannin, and by an alkali.
The action of the strong acids produces alterations on pro-
tein. Concentrated muriatic acid, when air is excluded, gives a
yellow solution, which becomes brown when oxygen gas is ad-
mitted. When the muriatic acid is allowed to act upon protein
in an open vessel, the colour of the solution gradually deepens
ligo blue. When heat is applied, the liquid becomes black,
170 ANIMAL AMIDES.
containing humin and sal-ammoniac, while an altered muriate
of protein is deposited.
In concentrated sulphuric acid, protein swells into a jelly.
When this jelly is cut into pieces, and put into cold water, that
liquid removes the excess of acid, and the mass shrivels up into
a white sulphate of protein, which is insoluble in water. This is
the substance to which Mulder has given the name of sulpho-
proteic acid. Its characters will be given afterwards. When
protein is boiled with dilute sulphuric acid, it becomes purple-
coloured.
Protein combines with alkalies and bases. With the alkalies
and alkaline earths, it forms compounds soluble in water, from
which it may be precipitated by the addition of alcohol. Its
compounds, with the earths and metallic oxides, are insoluble.
Mulder analyzed three specimens of protein, the first obtain-
ed from fibrin, the second from albumen of eggs, and the third
from albumen of serum of blood.* Dr Scherer analyzed also
three specimens, the first from the crystalline lens of the eye,
the second from albumen, and the third from fibrin.f The fol-
lowing table exhibits the results of these analyses :
Mulder. Scherer. Mean.
1. 2. 3. 1. 2. 3.
Carbon, 54-94 54-93 55-40 55-300 55-160 54-848 55-096
Hydrogen, 6-95 7-07 7*16 6.940 7-055 6-959 7*022
Azote, 15-83 15*83 16-00 16-216 15-966 15 847 15-948
Oxygen, 22-29 22-17 20-34 21-544 21-819 22-346 21-752
100-01 100- 98-90 100- 100- 100-
Mulder represents the constitution of protein by the formula,
C40 H31 Az5 O12 = 54-625. If we calculate from this formula,
we get
40 atoms carbon, = 30- or per cent 54-93
31 atoms hydrogen, = 3-875 ... 7-09
5 atoms azote, = 8-750 ... 16-02
12 atoms oxygen, =12-000 ... 21-96
54-625 100-00
Numbers which almost coincide with the mean of the six analy-
* Ann. der Pharm. xxviii. 74. f Ibid. xl. 43.
PROTEIN. 171
ses. Scherer represents the constitution of protein by the for-
mula C48 H36 Az6 O14 = 65. This formula gives,
48 atoms carbon, = 36* or per cent 55*38
36 atoms hydrogen, = 4-5 ... 6-92
6 atoms azote, — 10'5 ... 16-16
14 atoms oxygen, = 14-0 ... 25*54
65-0 100-00
This formula also comes very near the experimental quantity,
showing how difficult it is to determine by calculation the con-
stitution of such complicated compounds.
Protein has the property of combining with sulphuric acid,
and of forming an acid to which Mulder has given the name of
sulpho-proteic acid.
To prepare it, he mixed purified casein with concentrated sul-
phuric acid.* The solution was treated with ammonia, the ex-
cess of which was driven off by evaporation. Nitrate of silver
dropt into the liquid gave a precipitate of sulpho-proteate of sil-
ver, which was washed and dried at 266°. He prepared another
sulpho-proteate of silver by treating albumen of eggs in the same
manner. 487 of the salt from casein gave 739 carbonic acid
and 231 water : 120 parts gave 22 of metallic silver, and 760
gave 140 of sulphate of barytes. Hence the constituents in 100
parts must be,
Carbon, . 41-36
Hydrogen, . 5-27
Sulphuric acid, 6*35
Oxide of silver, 19-68
72-66
What is wanting to make up the hundred parts must be azote
and oxygen. But protein contains five atoms of azote and twelve
atoms of oxygen. Hence the azote in 100 parts of the salt must
weigh 14-08, and of consequence the oxygen must be 13-26 ;
477 pf the salt containing the albumen gave 647 of carbonic
acid, and 200 water. Hence 100 parts contain,
Carbon, . 37-08
Hydrogen, . 4*66
* Ann. der Pharm. xxxi. 127.
ANIMAL AMIDES.
According to these imperfect analyses, the two salts consist of,
From Casein. From Albumen.
Carbon, . 41-36 . 37-08
Hydrogen, . 5-27 '. 4-66
Azote, . 14-08
Oxygen, .(> 13-26
Sulphuric acid, 6*35
Oxide of silver, 19-68
100-00
Mulder considers the salt as composed of,
1 atom protein, . C40 H31 Az3 O12
1 atom sulphuric acid, . SO3
1 atom oxide of silver, . Ag O
He prepared sulpho-proteate of copper, and subjected it to
analysis. Its constituents were,
Carbon, . 32-17
Hydrogen, . 4-58
Azote, . . 9-87
Oxygen, . 16-85
Sulphuric acid, . 11-68
Oxide of copper, . 25-85
101-00
He considers it as composed of
1 atom protein, . C40 H31 Az5 O12
2 atoms sulphuric acid, . 2 (SO3)
5 atoms oxide of copper, . 5 (Cu O)
It is, in his own opinion, (C40 H31 Az5 O12 + SO3) -f (2 Cu
O + SO3) + (3 CuO + 3 Aq).
I think it unnecessary to enter into any examination of these
results, because the conclusions are obviously conjectural.
Tannate of Protein. — When albumen is mixed with water and
the liquid passed through a filter, if we mix it with a solution of
pure tannin, a white flocky precipitate falls, which is difficult to
wash. When dried at 266° it still retains its white colour, and
the tannin is unaltered, if the drying be cautiously conducted.
It was subjected to analysis by Mulder.* It contained two per
* Ann. der Pharm. xxxi. p. 129.
PROTEIN. 173
cent, of a calcareous salt. He endeavoured to get a purer tannate
by precipitating a solution of protein in acetic acid by tannin.
596 parts of this last salt gave 1154 of carbonic acid, and 290 of
water. The volumes of carbonic acid and azotic gases were to
each other as 58 to 5. Hence the constituents were.,
Carbon, 52-80
Hydrogen, 5 '41
Azote, . 10*87
Oxygen, 30-92
100-00
He represents the composition of the salt by the formula,
C58 H38 Az5 O23 resolvable into
1 atom protein, C40 H31 Az5 O12
1 atom tannin, C18 H5 O9
2 atoms water, . H2 O2
C58 H38 Az5 O23
Protein-oxide of Lead. — When a solution of protein in acetic
acid is mixed with a lead salt, a precipitate falls, composed of 10
atoms protein and 1 atom oxide of lead. If there be a great ex-
cess of acetic acid, the precipitate is composed of 5 atoms protein
and 1 atom oxide of lead.*
Sulpho-bi-proteic Acid. — If we dissolve albumen in acetic acid,
and add dilute sulphuric acid, we obtain a flocky precipitate, which
may be washed with alcohol. When dried at 266° it is a com-
pound of protein and sulphuric acid in definite proportions. It
was analyzed by Mulder. 132 parts of it gave 16 of sulphate
of barytes. Hence 100 parts contain 4*18 of sulphuric acid.
51 parts gave 95*2 of carbonic acid, and 31 of water. Hence it
contained,
Carbon, . . 50-90
Hydrogen, . 6-74
Azote, . . 15-03
Oxygen, . . 23-15
Sulphuric acid, . 4-18
100-00
The azote was not determined ; but calculated on the supposition
* Ann der Pharm. xxxi. p. 131.
174- ANIMAL AMIDES.
that it amounted to 20 atoms. He represents its constitution by
the formula C80 H64 Az10 O26 + SO3. Calculating from it we
get,
80 carbon, f:.,&i = 60 or per cent. 51-51
64 hydrogen, >- ^ = 8 ... 6-86
10 azote, m&% = 17-5 ... 15-03
26 oxygen, ~. = 26 ... 22-31
1 sulphuric' acid, =5 ... 4-29
116-5 100,
Mulder considers the precipitate as composed of
2 atoms protein, C80 H62 Az10 O24
2 atoms water, H2 O2
1 atom sulphuric acid, SO3
C80 H64 Az10 O26 SO3
Chloro-U-proteic Add. — This acid may be formed in the same
way as the last It is composed of 2 atoms protein, 2 atoms
water + 1 atom muriatic acid.
Action of Chlorine on Protein. — Mulder has made some expe-
riments on the action of chlorine on protein.* When a current
of dry chlorine is passed over protein it is absorbed, but the pro-
tein is not decomposed. The compound formed is a compound
of 1 atom protein and 1 atom of chlorous acid. Hence its for-
mula is C40 H31 Az5 O12 + CIO3. This compound is easily
washed and obtained in a state of purity.
To form it albumen was dissolved in water, and the liquid
filtered. This solution being treated with chlorine no gas was
evolved, but white flocks almost immediately appeared. They
increased in number. In a few hours the action was at an end.
The precipitate, which smelt of chlorous acid, was collected on a fil-
ter and washed. The washing was continued till the water nearly
ceased to be acted on by nitrate of silver. But, as the precipitate
is not altogether insoluble in water, the process must not be con-
tinued too long. The precipitate thus washed was pressed between
folds of filtering-paper, and dried at 176°. It has a white co-
lour with a tint of straw-yellow. It was finally dried at 212°.
When heated on platinum foil it melted, gave out gas, swelled
and burnt all away, without leaving any residue. During its
* Ann. der Pharm. xxxvi. 68.
PROTEIN. 175
combustion it gave out a smell analogous to saffron. The com-
bustion was very slow. It was subjected to an ultimate analysis
by Mulder. 527 parts of it gave 927 of carbonic acid, and 293
of water. 2750 parts of it gave 756 of chloride of silver. Hence
100 would have given 27*49 of chloride of silver = 6*87 chlo-
rine = 11-62 chlorous acid. The azotic gas was determined
by measurement, and was one-eighth part of the bulk of the car-
bonic acid gas. Hen^e the constituents are
Carbon, . 47-97
Hydrogen, . 6-18
Azote, . 14-10
Oxygen, . 20-13
Chlorous acid, 11-62
100-00
He gives as the formula for its composition C40 H31 Az5 O12
-f CIO3 ; that is to say, an atom of protein and an atom of chlo-
rous acid united together. Doubtless the oxygen of the chlorous
acid was obtained by the decomposition of three atoms of water.
When casein or fibrin was used instead of albumen, the com-
pounds formed were identical ; showing that the protein from
albumen is isomeric with that from casein and fibrin.
The liquid from which the chloro-proteic acid had been pre-
cipitated by chlorine was transparent, very acid, and smelled of
chlorous acid, though very little of that acid was present. When
saturated with ammonia only two or three bubbles of azotic gas
were extricated. Being evaporated to dryness, it left a great
quantity of sal-ammoniac. We see from this that the water had
been decomposed by the action of the chlorine ; the chlorous acid
united to the protein, but the muriatic acid remained dissolved
in the water.
Dry chloro-proteic acid is a straw-yellow powder with a fatty
feel. It is insoluble in alcohol and ether, and almost insoluble in
water. In concentrated sulphuric acid it dissolves without com-
municating any colour. When water is added to the solution
white flocks precipitate. When nitric acid is made to act upon it
for several days at the common temperature of the atmosphere
it gradually dissolves it, and converts it to xanthoproteic acid.
When acted on by muriatic acid cold, it is not converted into hu-
min as is the case with protein. It forms in it a colourless solu-
tion.
ANIMAL AMIDES.
Chloroproteic acid is soluble in barytes water. If no heat be
applied to the solution, carbonic acid may be passed through it.
If we then heat and filter it we have a colourless solution, which,
when evaporated, leaves a residue containing organic matter,
barytes, and chlorine. Chloroproteic acid is soluble in ammo-
nia with the evolution of much azotic gas. When the solution is
evaporated we obtain a residue soluble in hot water. Alcohol
throws down from this solution a new organic matter, while sal-
ammoniac remains in solution. Mulder distinguishes this new
organic matter by the name of Oxyprotein.
It is a yellow powder which must be treated with boiling alco-
hol to free it from the ammoniacal salt : and it always retains a
small quantity of chlorine. Mulder dried it at 212°, and subject-
ed it to an ultimate analysis. 603 parts of it gave 1108 of car-
bonic acid, and 358 water. 100 parts gave 15*12 of azote.
Hence the constituents are,
Carbon, . 50-16
Hydrogen, . 6.50
Azote, , 15.12
Oxygen, . 28-22
100-00
He represents the constitution by the formula C40 H31 Az5
O15 -f HO. It is therefore a hydrated oxide of protein ; or
protein combined with three atoms water. The chloroproteates
when they lose their chlorine by the action of ammonia do not
lose the oxygen of the chlorous acid, which forms with the pro-
tein a new body.
Oxy-protein constitutes a brittle and easily pulverized mass,
having an amber colour. It is heavier than water and soluble
in that liquid. It is scarcely soluble in alcohol and quite in-
soluble in ether. It dissolves in dilute sulphuric acid at a boil-
ing temperature. Strong boiling muriatic acid dissolves it also
without becoming coloured. By nitric acid it is converted into
xanthoproteic acid. It is soluble in potash, soda, ammonia, and ba-
rytes water. The aqueous solution is not precipitated by prus-
sic acid. Sulphuric acid throws down a white precipitate, which
dissolves when the liqour is heated, and again falls when it cools.
With infusion of nutgalls it gives an abundant precipitate. Ni-
PROTEIN. 177
trate of silver, chloride of iron, acetate of copper, are precipitat-
ed by it.
Mulder subjected this last precipitate to an analysis. 110
parts dried at 248° gave 4 of oxide of copper. 418 parts gave
752 carbonic acid, and 243 water. The azote amounted to
14 '8 7 per cent Hence the constituents are,
Carbon, . 49-06
Hydrogen, . 6-46
Azote, . 14-87
Oxygen, . 25-97
Oxide of copper, 3-64
100-
He represents the constitution by the formula C80 H63 Az10
O31 + CuO. He considers it as a compound of 1 atom oxy-
protein, and 1 atom oxide of copper, together with a compound
of one atom oxy-protein, and 1 atom water.
1 atom oxy-proteate of copper, C40 H31 Nz5 O15 -f CuO
1 atom oxy-protein -f Aq, C40 H31 Az5 O15 + HO
C80 H62 Az10 O30 + HO
Chloroxy-proteates. — Chloro-proteic acid, when dissolved in
barytes water, and a current of carbonic acid passed through the
solution to throw down the excess of barytes, and finally, when
filtered, gives a barytes salt, the constituents of which are con-
stant Alcohol being added to the aqueous solution, the new
salt is precipitated while the chloride of barium remains in solu-
tion. The new salt was washed with boiling alcohol and dried
at 266°.
When acetate of copper is dropt into the aqueous solution of
the barytes salt, as we have it before precipitation by alcohol,
bluish flocks precipitate. This precipitate was thoroughly wash-
ed and dried at 266*.
With chloride of iron a third salt was obtained. But the an-
alysis of it was found difficult
The barytes salt being subjected to analysis was found com-
posed of,
178 ANIMAL AMIDES.
Carbon, . 44-91
Hydrogen, 5-65
Barytes, . 11'88
Chlorine, . 1'70
64-14
What is wanting to make up the hundred consists, doubtless,
of azote and oxygen.
The copper salt contained,
Carbon, . 48-94
Hydrogen, . 6-33
Chlorine, . 1-73
Oxide of copper, 3-48
60-48
The ferruginous salt contained,
Carbon, . 48-07
Hydrogen, . 6-21
Chlorine, . 1-76
Peroxide of iron, 2-37
58-41
These analyses would require repetition, and the quantity of
azote should be determined.
Xantho-proteic Acid. — This name has been given by Mulder
to a yellow coloured acid, obtained first by Fourcroy, by treat-
ing fibrin or albumen with nitric acid. During the action
azotic gas is evolved, while oxalic acid and ammonia are formed.
This acid was analyzed by Mulder, who found it composed of,
Carbon, . 51-32 or 34 atoms = 25-5
Hydrogen, . 6-575 or 26 atoms = 3-25
Azote, . . 14- or 4 atoms = 7-00
Oxygen, . 28-105 or 14 atoms — 14-00
100-000 49-75
He considers it as a compound of,
1 atom xantho-proteic acid, . C34 H24 Az4 O12
2 atoms of water, . H2 O2
C34 H26 Az4 O14
PROTEIN. 179
Mulder confirmed these views by analyzing several of the salts
of xantho-proteic acid.*
He dissolved pure xantho-proteic acid in ammonia, and the
beautiful red liquid formed was evaporated on the water bath
till all the uncombined ammonia was driven off. The residue
was divided into two portions, the first of which was dried, and
the other again dissolved in water, and a current of chlorine gas
passed through it. The dried portion when heated to 212° gave
out ammonia. It lost its red colour and became orange yellow.
It was analyzed after being dried at 284°. 326 parts gave 618
of carbonic acid and 198 of water. The azote per cent, was es-
timated at 14 *3 7. Hence its constituents are,
Carbon, . 5170 or 34 atoms = 25*5
Hydrogen, 675 or 25 atoms — 8-125
Azote, . 14-37 or 4 atoms = 7*000
Oxygen, . 27-18 or 13 atoms - 13-000
100- 53-625
It is obviously composed of one atom xantho-proteic acid, and
one atom water. The ammonia had escaped and the hydrat-
ed acid remained.
When a current of chlorine was passed through the aminoni-
acal solution of xantho-proteic acid it lost its red colour and
white flocks with a shade of yellow precipitated. When
washed and dried at 212°, these flocks became lemon yellow.
This substance being analyzed was found to be a compound of two
atoms of hydrated xantho-proteic acid, and one atom of chlorous
acid. The analysis gave,
Carbon, . 49-61 or 68 atoms = 51-
Hydrogen, 6-22 or 50 atoms = 6 '25
Azote, . 12-89 or 8 atoms = 14-
Oxygen, 23-29 or 26 atoms = 26-
Chlorous acid, 7-36 or 1 atom = 7 -5
99-37 104-75
When the lemon yellow powder is dissolved in ammonia, azo-
tic gas is evolved. If we evaporate to dryness and dissolve off
the salamoniac by alcohol, we have the xantho-proteic acid in a
Ltate of purity.f
* Ann. der Pharm. xxviii 78. t Ibid, xxxvi. 81.
180 ANIMAL AMIDES.
SECTION I. OF ALBUMEN.
The term albumen employed by Pliny to denote the white
of an egg,* began, about the end of the last century, to be
applied to certain organic substances, which have the property
of coagulating, when heated to the temperature of 159.° In
their natural state they are soluble in water, but lose this solubi-
lity by coagulation. The word albumen does not occur in the- table
of the new chemical nomenclature, published by the French che-
mists in 1787. But we find it employed by Fourcroy about the
year 1789.f He and Vauquelin seem to have been the first che-
mists that attempted to fix its meaning with something like preci-
sion. Albumen may be obtained sufficiently pure from the white
of an egg and from the serum of blood.
When healthy blood is drawn from an animal, and left at rest,
it gradually separates into two portions ; namely, a gelatinous-
looking substance, containing all the red globules, and called the
cras&amentum or clot, and a liquid portion of a greenish-yellow
colour, which floats over the clot. This liquid is called the se-
rum of the blood.
It was first observed by Dr Harvey, that when serum is heat-
ed, it coagulates, and becomes as firm as the coagulated white of
an egg, though not so white.f The coagulating point, as deter-
mined by my thermometer, is 159°. It has been long known that
the white of an egg coagulates when heated to the same point.
Rouelle and Bouquet, about the year 1776, first compared serum
of blood and white of egg together, and concluded that both con-
tained a similar substance. To this substance, as has been al-
ready stated, the name albumen was applied, from a notion (now
known to be erroneous), that it existed in the state of greatest pu-
rity in the white of an egg.
The white of egg was examined with some care by Neumann,
who ascertained its property of being coagulated by heat, alco-
hol, and acids ; found that, in a gentle heat, it might be evapo-
rated to dryness, leaving a yellowish translucent substance, re-
sembling amber in appearance, and still capable of dissolving in
cold water. When thus dried, he found that 100 parts of albu-
* Plinii Hist. lib. xxviii. c. 6. f Ann de Chem. iiL 252.
\ De Generatione Anim. p. 161.
ALBUMEN. 181
men were reduced in one case to 10-15, and in another to 14*28
parts.*
It has not hitherto been possible to free albumen from all fo-
reign matters ; but it is brought to a state approaching purity by
the following process :
Mix the white of eggs with a considerable quantity of distilled
water, and rub the mixture intimately in a glass or porcelain
mortar, to break down all the membranous cells in which the
albumen is lodged, and allow it to dissolve in the water. Throw
the whole on a filter of very bibulous paper, and raise the tem-
perature of the filtered liquor to 160°. The albumen will coa-
gulate in white flocks. Let it subside to the bottom of a cylin-
drical glass in which the whole liquid has been put. Draw off
the clear liquid, and add a new portion of distilled water. Agi-
tate well, allow the albumen again to subside, and draw off the
water a second time. This process may be repeated a third time,
after which the albumen is to be dried in a gentle heat. Reduce
it to a fine powder, digest it in alcohol till that liquid ceases to
dissolve any thing. Finally, dry it over the steam-bath. It is
now as pure as it is in our power, with our present knowledge, to
make it.|
Albumen purified in this manner, when burnt, leaves about
2 per cent, of a gray-coloured ash ; doubtless, the earthy salts
(chiefly phosphates) which the white of egg contained. Scheele
observed, that when the white of an egg was dissolved by boiling
it in very dilute acids, it was again precipitated by adding some
concentrated acid. During this precipitation a smell of sulphu-
retted hydrogen was perceptible, showing clearly that it contains
sulphur.J
Albumen prepared in this way is transparent, and has an
amber colour. When put into water it swells up, becomes opaque
and white, and assumes the appearance of coagulated white of
egg. According to Chevreul, 1000 parts of water dissolve 7
parts of coagulated albumen.
It dissolves in concentrated muriatic acid, and the solution, as
* Neumann's Chemistry, p. 554.
f It will not be freed from soda nor from the earthy phosphates which may
have existed in white of egg. To get rid of these it must be treated with an
acid.
J Scheele's Chemical Essays, p. 268.
182 ANIMAL AMIDES.
was first noticed by Caventou and Bourdois, has a fine blue
colour. The addition of water precipitates the albumen white ;
but the acid still retains its blue colour. Caustic potash or soda
dissolves it, and the solution has the property of blackening sil-
ver. Coagulated albumen and fibrin possess exactly the same
properties.
Uncoagulated albumen seems to possess acid characters,
though it does not alter the colour of vegetable blues. In the
serum of blood, it is combined with soda. When we add a so-
lution of a metallic salt to the serum of blood, and then drop in
as much caustic potash as will decompose the salt, the metallic
oxide does not precipitate, but remains in solution united to the
albumen.
When to a solution of albumen we add acetic acid, and then
drop into it prussiate of potash, a copious white precipitate falls.
This is one of the most delicate tests of the presence of albumen
in liquid.
Protosulphate of iron and sulphate of copper, according to
Schiibler, precipitate a very dilute solution of albumen ; but if
we increase the quantity of the metallic salt, the precipitate
again dissolves.
The salts of tin, lead, bismuth, silver, and mercury, precipitate
albumen white. The subacetate of lead gives a precipitate with
a very minute quantity of albumen. Corrosive sublimate precipi-
tates albumen from a liquid containing only 5^o crth of its weight
of that principle. The precipitate is a compound of corrosive
sublimate and albumen. By this combination, the poisonous quali-
ties of corrosive sublimate are destroyed. Hence, the white of
egg constitutes the best antidote to this poison. According to
Orfila the albuminate of corrosive sublimate (if the term may be
permitted) is composed of,
Albumen, . 62-22 or28
Corrosive sublimate, 37 '78 or 17
100-00
According to Bostock, of
Albumen, . 88-89 or 136 = 28 x 5 nearly.
Corrosive sublimate, 1 1 • 1 1 or 17
lOO'OO
ALBUMEN. 183
Albumen was analyzed by Gay-Lussac and Thenard, by Mi-
chaelis and by Prout. Gay-Lussac and Thenard merely dried
the white of an egg in the temperature of 212°, and analyzed it
without any attempt to purify it.* Dr Prout employed albumen
from the serum of the blood of a patient labouring under a slight
inflammation. Mulder has made a more recent analysis, and
took the precaution to purify his albumen by the process de-
scribed at the beginning of this section. Hence it would be free
from a small portion of mucus, which is known to exist in the
white of egg. The result of all these analyses will be seen in the
following table :
Michaelis. Mulder.
Gay-Lussac From arte- From venous White of Serum of
& Thenard. rial blood. blood. Prout. egg. blood.
Carbon, . 52-883 53 009 52-660 49-750 53-960 54-398
Hydrogen, 7-540 6-993 7-350 7-775 7-052 7-024
Azote, 15-705 15-562 15-505 15-550 15-696 15-843
Oxygen, 23-872 24-436 24-484 26-925 23-292 22-744
100- 100- 100- 100- 100- 100-
But Mulder has more recently subjected albumen to a new
analysis, and determined the phosphorus and sulphur which it
contains. The following are his results :f
From Eggs.
Carbon,
54-48
Hydrogen, .
7.01
Azote,
15-70
Oxygen,
22-00
Phosphorus, .
0-43
Sulphur,
0-38
100- 100-
He represents its constitution by the formula, 10 (C40 H31 Az5
O12) -f Ph -f S2, or ten atoms protein united to one atom phos-
phorus and two atoms sulphur. If we calculate from this formula
we get,
400 atoms carbon, = 300 or per cent 54*33
310 atoms hydrogen, = 38-75 ... 7*02
50 atoms azote, = 87-50 ... 15-84
120 atoms oxygen, =120-00 ... 2173
* Recherches Physico-Chemiques, ii. 331. f Ann. der Pharm. xxviii. 74.
ANIMAL AMIDES.
1 atom phosphorus, — 2-00 ... 0-36
2 atoms sulphur, = 4-00 ... 0-72
552-25 100-
Still more lately albumen has been subjected to a careful
analysis by Dr Scherer in Liebig's laboratory.* He analyzed
albumen from blood, from eggs, from the liquor of a hydrocele,
and from pus. The result came so near those of Mulder, that
it seems unnecessary to state them. It has been already stated,
that his formula for protein is C48 H36 Az6 O14. It differs from
that of Mulder only by an atom of hydrogen. In the present
state of our knowledge, it is difficult, if not impossible, to decide
which of the two formulas is nearest the truth.
It is evident from the analyses that the chemical constitution
of albumen from the egg and from serum is identical. Yet re-
agents do not in all cases produce the same effect upon each.
Chevreul informs us, that ether and oil of turpentine coagulate
white of egg, while, according to Tiedemann and Gmelin, they
do not produce the same effect on the serum of blood.
SECTION II. OF ALBUMEN FROM SILK,
This. substance was first particularly examined by M. Mulder
in 1836. He obtained it by the following process.
Silk was treated with boiling water till every thing soluble in
that liquid was taken up. The aqueous solution was evaporated
to dryness and the residue digested in alcohol and ether. The
matter not acted upon by these liquids was a mixture of coagu-
lated albumen and gelatin. Boiling water dissolved the latter
substance and left the albumen in a state of purity.
It is brittle, easily reduced to powder, and heavier than water.
When placed on a hot iron it is charred and emits the smell of
burning horn. It burns with flame, leaving a large quantity of
white ashes. When distilled per se it gives out much carbonate
of ammonia and empyreumatic oil. A dry portion of it being
left for 24 hours in concentrated sulphuric acid remained unal-
tered. But when heat was applied it was charred with the evo-
lution of sulphurous acid gas. Moist albumen dissolves in sul-
phuric acid at the common temperature of the atmosphere. In
dilute sulphuric acid it is not soluble even when heat is applied
* Ann. de Pharra. xl. 36.
CASEIK. 185
Nor does it dissolve in cold nitric acid ; but it is easily soluble
in that acid when assisted by heat. Moist albumen dissolves in
nitric acid at the common temperature, and oxalic acid is formed.
It is not acted on by muriatic acid unless heat be applied when
it is dissolved. Moist albumen dissolves in it at the ordinary
temperature of the atmosphere. By phosphoric acid and heat it
is charred and decomposed.
When dissolved in concentrated acetic acid, the solution has a
fatty feel, which Mulder considers as a remarkable distinguish-
ing character. When prussiate of potash is dropt into this so-
lution a beautiful green precipitate falls, which is insoluble in wa-
ter. By this property a minute quantity of this albumen may
be discovered.
It dissolves in potash, soda, and ammonia, and is precipitated
again by acids. If we add acetic acid to the potash solution it
will not blacken silver. It is insoluble in carbonated potash, so-
da, or ammonia.*
According to Mulder's analysis it is composed of,
Carbon, . 54-005
Hydrogen, . 7-270
Azote, . 15*456
Oxygen, . 23-269
100-OOOf
These numbers come sufficiently near the various analyses of
albumen from blood and eggs to show that all these substances
are isomeric.
SECTION III. OF CASEIN.
Milk is the well known liquid secreted by the females of the
whole class of mammalia to nourish their new-born offspring.
The milk of the cow has been used as a common article of food
from the earliest ages. Hence its appearance, its taste, and its
nourishing properties are known to every person.
Milk underwent a chemical examination from Neumann. He
ascertained the quantity of water which it contained, and Dr
Lewis showed that its boiling point was the same as that of wa-
ter ; that it is coagulated by acids and also by alkalies. The co-
* Poggendorf s Amialen, xxxvii. 608. f Ibid. xl. 270.
186 ANIMAL AMIDES.
agulum by acids falls to the bottom of the serum, but that by al-
kalies swims on the surface.*
Neumann also made some experiments on cheese, a well-known
preparation of curd. He tried the action of water, nitric acid,
sulphuric acid, muriatic acid, and caustic alkalies, both fixed and
volatile ; and found that they dissolved cheese either partially or
completely.
Scheele examined milk and curds in 1780, and was the first
person who compared curds with coagulated white of egg. He
showed that the properties of both were the same. Milk is coa-
gulated by acids, and the coagulum formed is a compound of the
acid employed and curd. The mineral acids when used in ex-
cess dissolve a portion of the precipitate, but the vegetable acids
dissolve little or nothing. Hence the reason why more curd is
obtained when milk is coagulated by vegetable than by mineral
acids.f
The first attempt to make a regular analysis of milk was by
Parmentier and Deyeux, in a memoir which gained the prize of-
fered by the Society of Medicine of Paris, for the year 1790.J
These chemists examined the curd of milk in considerable detail,
and determined many of its properties, though they did not ob-
tain it in a state of purity. They distinguished it by the name
of matiere caseeuse.
Fourcroy in his Systeme des Connoissances Chimiques, pub-
lished about the beginning of the present century, gives a pretty
detailed account of the curdy part of milk, chiefly taken from the
Memoir of Parmentier and Deyeux. He distinguishes it, as these
chemists did, by the name of caseous matter. §
In 1808, the second volume of the Animal Chemistry of Ber-
zelius was published in Stockholm. It contains an excellent
analysis of milk, || and a detailed examination of the characters
of the curdy portion, which he distinguishes by the name of ost,
(cheese). He pointed out some difference in the characters of
* Lewis's Neumann's Chemistry, p. 573.
f Scheele's Chemical Essays, p. 265.
\ See an abstract in Ann de Chim. vi. 183. The memoir itself was publish-
ed in Paris in 1800.
§ Vol ix. p. 515 of the English translation.
II Forelassningor i Djuskemier, ii. 409.
CASEIN. 187
ost and albumen, which Scheele had from his observations pro-
nounced identical.
I do not know who first applied to the curdy part of milk the
name casein. But it occurs in the 27th volume of the Diction-
naire des Sciences Medicales, published in 1818. The word case-
us, applied to the same substance, is found in the Dictionnaire de
C/timie of Klaproth and Wolff, the French translation of which
appeared in 1810.
Casein may be obtained from cow's milk by the following pro-
Mix skimmed milk with dilute sulphuric acid. The casein
and acid unite and precipitate in the state of a white curd. Let
the curd be collected on a filter, and well washed with water to
remove the whey which it contains. Thus cleaned, it is to be
mixed with water and digested over carbonate of barytes. The
sulphuric acid unites with the barytes, while the casein set at li-
berty dissolves in the water. When this liquid is filtered to free
it from the sulphate of barytes and the excess of carbonate em-
ployed, it has a pale yellow colour, and resembles in consistence
a solution of gum. When heated in an open vessel it emits the
smell of boiling milk, and a white pellicle forms on the surface,
similar to that which is formed on the surface of boiling milk.'
When the liquid is evaporated to dryness in a gentle heat we
obtain the casein in the state of an amber-coloured mass, which
is still soluble in water. The aqueous solution is coagulated by
all acids, even by the acetic, especially when assisted by heat
This property distinguishes casein from albumen ; which last is
not precipitated by acetic acid.
Braconnot assures us that casein obtained by the above process
is not quite free from impurity. He recommends -the following
process as better. Take 400 parts of curd formed by rennet,
and well washed in boiling water to get red of the whey. Mix
them with one part of bicarbonate of potash in crystals, and a
sufficient quantity of water. Heat the mixture, an effervescence
takes place, and the curd and alkali combine and dissolve in the
water. When this solution is cautiously evaporated to dryness
it constitutes the soluble casein of Braconnot, a substance which
he recommends for a variety of useful purposes.
To obtain pure casein, dissolve a quantity of soluble casein
in boiling water. Pour the solution into a funnel, having its
188 ANIMAL AMIDES.
beak shut up, and let it remain at rest for 24 hours. A quan-
tity of cream collects on the surface, which is separated by allow-
ing the clear solution to pass through the funnel, retaining the
cream. Pour into this clear liquid a little sulphuric acid. A
curdy precipitate falls, consisting of casein combined with sul-
phuric acid. Wash this precipitate, heat it in water mixed with
a very small quantity of carbonate of potash, scarcely sufficient
to dissolve all the matter. We obtain a mucilaginous liquid,
which, while still hot, must be mixed with its own bulk of alco-
hol. No precipitate should fall till 24 hours after the mixture.
The precipitate consists of butter, sulphate of potash, and a por-
tion of casein. Let the liquid be passed through a cloth. We
obtain a transparent liquid, which, when evaporated to dryness,
leaves pure casein.*
When the aqueous solution of casein is left to itself it gradu-
ally alters, gives out the smell of old cheese, and becomes ammo-
niacal.
When alcohol is poured upon casein, dried in a low heat, it
becomes opaque, and assumes the aspect of coagulated albumen.
The alcohol abstracts the water with which it was united, and
thus occasions the alterations. At the same time the alcohol
dissolves a portion of the casein, which remains when the alco-
holic liquid is evaporated to dryness. Casein is still more solu-
ble in boiling alcohol. The excess precipitates as the liquid cools.
By this solution the characters of the casein are not in the least
altered.
Anhydrous casein, or casein digested or dissolved by alcohol,
swells in water, and gradually dissolves into a mucilaginous fro-
thy mass, which becomes transparent and liquid when heated,
and then assumes the original characters of casein dissolved in
water.
Acids act upon casein very nearly as upon albumen. With
a little acid it forms a compound soluble in water ; but when
the quantity of that acid is increased, the compound becomes
little soluble. By washing with water we may remove this excess,
and thus render it again soluble in water. The precipitate by
acetic acid may be again dissolved. But much more acid is ne-
cessary for that purpose than is required for albumen or fibrin.
Solutions of casein in acids are precipitated by prussiate of po-
* Ann. de Chim. et de Phys. liii. 343.
CASEIN. 189
tash. But phosphoric and arsenious acid, according to Bracon-
not, do not precipitate casein, though, when we add prussiate
of potash to a solution of casein containing phosphoric acid, a
copious precipitate falls.* Alcoholic solutions of casein are not
precipitated by acids. And alcohol dissolves readily the preci-
pitates thrown down from water by acids.
Casein combines with the alkalies without undergoing any al-
teration, unless the alkaline solutions be concentrated and heat
be applied. In that case the solution becomes brown, ammonia
is given out, and an alkaline sulphuret is formed.
Casein combines with the alkaline earths. If the quantity of
earth be small, the compound is soluble, and the earth is not pre-
cipitated by exposure to the air, or by passing through the liquid
a current of carbonic acid gas. Indeed casein, as extracted from
milk, appears to contain caseate of lime. When casein is placed
in contact with an excess of hydrate of lime, a bulky compound
is formed very little soluble in water. When this compound is
boiled in water, the casein is gradually decomposed. A kind of
extractive, soluble in water, is formed, from which oxalic acid pre-
cipitates lime.
If we heat sugar with a concentrated solution of casein, it loses
its consistence and becomes very fluid. But if we increase the
quantity of sugar considerably, the casein separates in curdy
masses or clots. But when washed these clots again dissolve in
water. When casein is mixed with gum-arabic, it loses its solu-
bility entirely ; owing, in the opinion of Braconnot, to a free acid
and earthy salts contained in the gum.
Solution of casein in water is precipitated by all the earthy
and metallic salts capable of precipitating uncoagulated albumen.
Tannin throws it down both from its aqueous and alcoholic so-
lution.
Like albumen it is capable of existing in two states, uncoagu-
lated and coagulated. The characters of uncoagulated casein
have been given. We must now state the properties of coagu-
lated casein.
For coagulation it requires the boiling temperature or rennet.
When an aqueous solution of casein or skimmed milk is mixed
with rennet and gently heated, coagulation takes place. Rennet
is formed by digesting the innermost membrane of a calfs sto-
• Ann. de Chim. et de Phys. liii 344.
190 ANIMAL AMIDES.
raach in cold water. A small quantity of a peculiar substance
is dissolved, to which the name pepsin has been given, because it
has the extraordinary property of dissolving food and converting
it into chyme in the stomach of living animals. A very minute
quantity of pepsin is sufficient to coagulate a great quantity of
milk. Berzelius evaporated a quantity of rennet to dryness in
a gentle heat He mixed one part of the dry residue with 1800
parts of milk, and heated the whole to 122°. The whole casein
was so completely coagulated, that scarcely a trace of it could
be detected in the whey. The dry rennet being separated was
found to weigh 0*96. So that one part of pepsin coagulated
45000 parts of milk.*
Coagulated casein, when pure and dried, is hard, translucent,
and yellowish. Unless it be well freed from all traces of butter,
it has a resinous lustre. This may be removed by digesting the
coagulated casein in ether, which dissolves the butter without al-
tering the casein. When put into water it softens and swells ;
but does not dissolve. When strongly heated before it has been
quite dried, it is rendered soft without melting, and becomes
elastic like caoutchouc. If the temperature be increased, it
swells, melts and burns with flame. The products obtained when
it is distilled are the same as those given by albumen. The com-
pounds of coagulated casein with acids and alkalies are similar
to those of uncoagulated albumen with the same bodies. But
when the acid is withdrawn by means of carbonate of barytes or
carbonate of lime, the casein does not dissolve in water, as hap-
pens with uncoagulated casein.
Coagulated casein (or cheese, as it is called in common lan-
guage,) is soluble in concentrated sulphuric acid, from which it
is precipitated by water. It dissolves in nitric acid of 1*29, to
which it communicates a yellow colour. Muriatic acid dissolves
it very slowly, requiring to be continued for several days. The
solution, like that of albumen and fibrin, becomes blue, if the
temperature has exceeded 60°. By degrees the colour changes
to a dirty violet When the acid is saturated with potash, the
colour disappears, and the cheese is precipitated greyish-white.
With concentrated acetic acid it forms a jelly, and dissolves when
we add water and apply heat But a great deal of acid is neces-
sary. It is very soluble in the hydrates and in the carbonates of
* Traite de Chimie, vii. 601.
CASEIN. 191
potash and soda, when diluted with water and cold. Caustic
ammonia dissolves it very slowly and imperfectly.
When cheese coagulated by rennet is burnt, it leaves 6 per
cent, of subsesqui -phosphate of lime, and half a per cent, of caus-
tic lime, which had been in combination with the casein in the
milk.
When cheese is long kept, it undergoes peculiar alterations,
which have been investigated by Braconnot* He mixed 270
grammes of skim-milk cheese with a litre of water, and left the
mixture a month to putrefy, at a temperature between 68° and 77°.
The greatest part of the cheese dissolved, and the solution was
separated from the undissolved portion by filtration. It had a
putrid smell, without anything sulphureous. Being evaporated
to the consistence of honey, it gradually congealed into a gra-
nular mass. Alcohol dissolved a portion of this matter, and left
a portion untouched.
The undissolved portion was dissolved in water and treated
with animal charcoal, which deprived it of its colour. Being now
left to spontaneous evaporation, it gave small brilliant crystalline
vegetations, and fine needle-form crystals, constituting cauliflower
rings round the borders of the liquid. To obtain this substance
white, it was necessary to dissolve and crystallize it several times.
Braconnot distinguished this substance by the name of apose-
pedin. f Proust had previously called it caseic oxide. Its
properties have been already detailed in a former part of this
volume. The first attempt to analyze casein was made by The-
nard and Gay-Lussac. The casein which they employed was
obtained by spontaneous coagulation. It was washed thoroughly
with water, and then dried and pulverized. It was then burnt
with chlorate of potash, and the quantity of carbonic acid, &c. ob-
tained, determined from which the constituents were inferred.^
Mulder has shown that its base is protein, and that it consists of
ten atoms of protein united to one atom of sulphur, or 10
(C^'H31 Az5 O12) + S. Dr Scherer also subjected it to analy-
sis. § Milk was mixed with twice its bulk of alcohol ; and the
coagulum was boiled repeatedly in alcohol and ether. When all
the butter was removed, the coagulum was boiled in water to se-
* Ann. de Chim. et de Phys. xxxvi. 159.
f From euro and rmrtJetv, putrefaction.
| Recherches Physico-Chimiques, ii. 382. § Ann. der Pharrn. xl. 40.
192 ANIMAL AMIDES.
parate the sugar of milk. It was then dried at 212°. Its con-
stituents were,
Carbon, . 54-825
Hydrogen, . 7-153
Azote, . 15-628
Oxygen, j 2
Sulphur, /
100-000
Several other analyses gave nearly the same result
SECTION IV. OF FIBRIN FROM BLOOD.
When the crassamentum of blood is put into a linen cloth,
and carefully washed till all the red colouring matter is remov-
ed, the substance which remains has a fibrous texture, and is, on
that account, distinguished by the name of fibrin. This name
seems to have been imposed by Fourcroy and Vauquelin ; at
least I have not observed it in the writings of any earlier chemist.
It was long the opinion of physiologists, that the globules of
the blood consisted of a nucleus of fibrin enclosed in a vesicle of
colouring matter. Hence it was supposed was the reason why
it exists in the crassamentum. But later observations have con-
siderably modified this opinion. Piorry and Scelles de Monde-
zert have remarked, that, if we cautiously and rapidly remove the
serum which floats on the crassamentum, we will frequently find
it become opaline and muddy, and finally covered with a skin
analogous, if not identical with fibrin.* According to Muller,
if we amputate the thigh of a frog, and after mixing the blood
that flows out with an equal quantity of water, holding sugar in
solution, throw the whole upon a moistened filter, the red glo-
bules, which are very large in that animal, are retained upon the
filter, while a colourless and clear liquid passes through. In this
liquid, a coagulum of fibrin speedily appears.
From these facts, there seems no reason to doubt, that the
fibrin exists in the serum of blood as well as the albumen, and
that the globules consist of the red-colouring matter, and a white
insoluble substance analogous to coagulated albumen or fibrin.
Indeed, Lecanu has shown, by numerous experiments, that the
* Lecanu, Etudes Chimiques sur le Sang Humain, p. 43.
FIBRIN FROM BLOOD. 193
globules consist of three distinct substances, namely, hematosin,
albumen, and fibrin.*
Fibrin may be procured likewise from the muscles of animals.
Mr Hatchett cut a quantity of lean beef into small pieces, and
macerated it in water for fifteen days, changing the water every
day, and subjecting the beef to pressure at the same time, in or-
der to squeeze out the water. The shreds of muscle, which
amounted to about three pounds, were now boiled for five hours every
day for three weeks in six quarts of fresh water, which was re-
gularly changed every day. The fibrous part was now subject-
.ed to pressure, and then dried on the water-bath. In this state,
it possessed the characters of fibrin.f
It is very difficult to free the fibrin of blood completely from
hematosin. The easiest way is to stir new-drawn ox-blood
rapidly with a stick. The fibrin adheres to the stick. Let it be
taken off, and washed in cold water till that liquid ceases to be
coloured by it. Then steep it in water for twenty-four hours,
washing it frequently and carefully during that time, Finally,
let it be digested in alcohol, or still better in ether, to separate
a fatty matter which it still contains.
Fibrin, when dried, assumes a dirty-yellow colour, and be-
comes hard and brittle, but continues opaque. When put into
water, it imbibes that liquid, and recovers its original appear-
ance, and nearly its original weight. It has neither taste nor
smell. When heated, it does not alter till it reaches the point
of decomposition. It then melts, swells greatly, catches §re,
and burns with a yellow flame, giving out much smoke. It is
insoluble in water, whether cold or hot. When boiled in that
liquid, it contracts and becomes at last extremely friable. The
water becomes muddy, and if we evaporate it to dry ness, we ob-
tain a solid, brittle, yellow substance, having the smell of boiled
meat, and soluble in water. This substance does not assume the
form of a jelly, and is precipitated by tannin in insulated flocks,
which do not unite into an elastic mass like tannate of gelatin.
Fibrin, like albumen and casein, possesses both the characters
of an acid and a base. The concentrated acids cause it to swell,
and to become gelatinous and transparent. With sulphuric acid,
it swells into a yellow jelly, but. does not dissolve. Heat is evolv-
* Lecanu, Etudes Chimiques sur le Sang Humain, p. 5.
f Phil. Trans. 1800, p. 827.
194 ANIMAL AMIDES.
ed, and, unless the temperature is kept down, sulphurous acid is
disengaged, and the fibrin becomes black. When the acid is di-
lute, or when water is poured on the jelly, the fibrin suddenly
contracts to less than its original bulk. This contracted mass is
a compound of sulphuric acid and fibrin. When it is collected
on a filter, and washed with water, it becomes transparent and
gelatinous, and at last dissolves completely in water. This so-
luble matter is a neutral compound of sulphuric acid and fibrin.
The addition of sulphuric acid renders it insoluble as at first.
Nitric acid gives fibrin a yellow colour. When cold and di-
lute, it forms two compounds with fibrin, as sulphuric acid does,
and having the same characters. But when heat is applied, and
the acid is strong, azotic gas is given out, the acid becomes yel-
low, and the fibrin is converted into a yellow or orange mass,
which does not dissolve in water. This substance was first de-
scribed by Fourcroy under the name of yellow acid.
Pyrophosphoric acid produces with fibrin the same phenomena
as sulphuric acid. With common phosphoric acid, fibrin does
not swell into a jelly, but forms a compound soluble in water, and
not precipitated by an excess of acid.
In concentrated acetic acid fibrin becomes immediately soft
and transparent, and, with the assistance of heat, is converted
into a tremulous jelly. By adding hot water, this jelly is
completely dissolved with the evolution of a small quantity of
azotic gas. The solution is colourless, and has a mawkish and
slightly acid taste. During its evaporation a transparent mem-
brane appears on the surface, and after a certain degree of con-
centration the gelatinous substance is again reproduced. When
completely dried it is a transparent mass which reddens litmus-
paper, but is insoluble in water without a fresh addition of acetic
acid. When ferrocyanate of potash, an alkali, or sulphuric, ni-
tric, or muriatic acid is dropped into this solution a white preci-
pitate falls. The acid precipitate is a compound of fibrin and the
acid. If it be washed, a certain portion of acid holding fibrin
in solution is carried off, and the remainder is soluble in water.
This solution contains a neutral compound of the acid and fibrin.
The addition of a little more of the acid causes it to precipitate
again. *
* Berzelius, Annals of Philosophy, ii. 20.
FIBRIN FROM BLOOD.
195
In weak muriatic acid fibrin shrinks and gives out a small
quantity of azotic gas ; but scarcely any portion is dissolved even
by boiling ; nor does the acid liquid afford any precipitate with
ammonia or ferrocyanate of potash. The fibrin thus treated is hard
and shrivelled. When repeatedly washed with water it is at last
converted into a gelatinous mass, which is perfectly soluble in
warm water. The solution reddens litmus-paper, and yields a
precipitate with acids as well as alkalies. Fibrin, therefore,
combines with muriatic acid in two proportions. The one gives
a neutral compound soluble in water, the other with an excess of
acid is insoluble, but becomes soluble by the action of pure wa-
ter.*
In caustic alkali fibrin increases in bulk, becomes transparent
and gelatinous, and at length is completely dissolved. The solu-
tion is yellow with a shade of green. Acids occasion in it a pre-
cipitate which gradually becomes confluent. Alcohol occasions
a precipitate in it. Some alteration is produced upon the fibrin
by the alkali, but nothing in the least similar to a soap is formed.f
Ammonia behaves with fibrin as potash does, only the action
is slower.
When sulphate of soda or nitrate of potash is put into blood,
it is prevented from coagulating, and of course the fibrin does
not separate.
Fibrin possesses exactly the characters of coagulated albumen.
Fibrin from blood was analyzed by Gay Lussac and The-
nard,J by Michaelis,§ and more recently by Mulder Jj and Vogel.lf
The following table exhibits the result of these analyses :
Gay Lussac
and Thenard.
Carbon, 53-360
Hydrogen, 7-021
Azote, . 19-934
Oxygen, 19-685
100000 100000 100-000 100000 100-00
* Berzelius, Annals of Philosophy, ii. 20. f Ibid.
{ Recherches Physico-chimiques, ii. 328.
§ Diss. de partib. constitut. sanguin. arteriosi et venosi.
|j Poggendorf's Annalen, xl. 255. f Jour, de Pharmacie, xxv. 587-
** Varrentrapp and Will obtained 16 02 percent, of azote. — Ann. der Pbarm
xxxix. 292.
Michael is.
Arterial.
51-374
Venous.
50-440
Mulder.
53-328
Vogel.
51-76
7-254
8-228
6-830
7O9
17-587
17-267
15-465
1805 •
23-785
24-065
24-377
23-10
196 ANIMAL AMIDES.
The differences between these results are considerable, proba-
bly depending upon the presence of some foreign matter. The
mean of the five is as follows :
Carbon, . 52-05
Hydrogen, . 7-28
Azote, . 17-66
Oxygen, . . 23-51
100-00
Before we can draw any conclusion from these analyses we
must know the atomic weight of fibrin. Berzelius made some
experiments to show that its atomic weight may be determined,
but has stated no numerical results. Mulder made several salts
of fibrin and subjected them to analysis. It will be worth while
to state the results which he obtained.
1. Fibrate of copper. — When sulphate of copper is added to a
solution of fibrin in caustic potash, green flocks of fibrate of cop-
per precipitate. This salt being analyzed gave,
Fibrin, . 798 or 64-35 = 1 atom.
Oxide of copper, 62 or 5' = 1 atom.
3. Subsesqui-Jibrate of lead. — It was obtained by mixing sub-
acetate of lead with fibrate of potash. It was composed of,
Fibrin, . 38331 or 63.896 = 1 atom.
Oxide of lead, 5599 or 21- = 1± atom.
3. Fibrate of silver. — It was prepared by dissolving fibrin in
acetic acid and mixing the solution with nitrate of silver. It
was composed of,
Fibrin, . 6984 or 62-52 = 1 atom.
Oxide of silver, 403 or 3-625 = J atom.
The mean atomic weight of fibrin deduced from these three
analyses is 63-588.
4. Mulder passed a current of dry muriatic acid over dry
fibrin, till no more absorption took place, and then passed through
the apparatus a current of dry air till muriatic acid fumes no
longer made their appearance. 1112 of fibrin by this treat-
ment increased in weight 80. Hence the muriate of fibrin was
composed of,
Muriatic acid, 80 or 4-625 = 1 atom.
Fibrin, . 1112 or 64-287 = 1 atom.
The mean of all these analyses gives us 63.76 for the atomic
FIBRIN FROM BLOOD. 197
weight of fibrin, or rather protein. Now the numbers which
agree best with the mean of the analyses, and with the atomic
weight deduced from the experiments of Mulder, are the follow-
ing:
45 atoms carbon, . — 33-75 or per cent. 52-03
38 atoms hydrogen, = 4*75 ... 7-32
6 J atoms azote, . =11-375 ... 17-53
15 atoms oxygen, . =15-00 ... 23-12
64-875 100-00
More lately Mulder has endeavoured to determine the quan-
tity of sulphur and phosphorus which occurs in fibrin. These
two substances he considers as combined and forming a sulphu-
ret of phosphorus. By an ultimate analysis of fibrin he got,
Carbon, . 54*56
Hydrogen, . 6-90
Azote, . 17-72
Oxygen, . 22-13
Phosphorus, 0-33
Sulphur, . 0-36
102-00*
He represents the constitution by 10 (C40 H31 Az5 O12) PhS.
Calculating from this, we get,
400 carbon, . =r 300- or per cent. 54-52
310 hydrogen, •= 38-75 ... 7-04
50 azote, . = 87-5 ... 16-90
120 oxygen, . =120-0 ... 21*35
1 phosphorus, = 2- ... 0-36
1 sulphur, = 2- ... 0-36
550-25
Fibrin from venous human blood was purified by Dr Scherer,f
and subjected to various ultimate analyses; being burnt sometimes
with oxide of copper, but in four out of six analyses by chromate
of lead. The following is the mean result of these six analyses :
Ann. der Phar m. xxviii. 74. f Ibid. xl. 33.
198 ANIMAL AMIDES.
Carbon, . 54-393
Hydrogen, . 6-963
Azote, . 15-783
Oxygen, ^
Sulphur, 22-861
Phosphorus, )
100-
Numbers which agree exceedingly well with the result of
Mulder's analyses. We may therefore conclude that fibrin is a
compound of ten atoms protein, with one atom sulphur, and one
atom phosphorus, or 10 (C40 H31 Az5 O12) + S + Ph.
SECTION V. OF FIBRIN FROM SILK.
This species of fibrin has been examined with much ingenuity
and skill by M. Mulder.* Raw silk was boiled successively in
water, alcohol, ether, and acetic acid, till every thing soluble in
these liquids was removed ; what remained was considered as
fibrin. In yellow raw silk it amounted to 53-37, and in white raw
silk to 54 '04 per cent,
Its colour is white, but it is much softer and more brittle than
natural raw silk, and has much less coherence. So that a tuft of
it breaks with the greatest facility into an infinite number of very
minute threads, spreading out in every direction. Hence neither
so beautiful nor so strong a fabric could be woven of it, as of raw
silk in its natural state.
It is heavier than water. When burnt it emits the smell of horn.
When distilled it gives much carbonate of ammonia, empyreu-
matic oil, and water, and leaves a bulky charcoal. When thrown
upon a red hot plate of iron it melts, or at least becomes soft,
swells out, and burns with a light blue flame, and leaves a bulky
charcoal.
It is insoluble in water, alcohol, ether, and acetic acid. It is
equally insoluble in fat and volatile oils. It dissolves immedi-
ately in concentrated sulphuric acid at the common temperature
of the atmosphere, forming a light brown thick solution. When
heated it becomes first of a beautiful red, then of a brown, and
finally of a black colour, while sulphurous acid is given off.
From this solution it is not thrown down by water. But when
* Poggendorf's Annalen, xxxvii. 603, and xl. 266.
FIBRIN FROM SILK. 199
infusion of nutgalls is added an abundant white precipitate sepa-
rates. W hen the solution is diluted with water this matter falls
like a jelly to the bottom, but is again dissolved by agitation.
When potash is added white flocks fall down, but they are again
dissolved, when a great excess of potash is added.
Fibrin of silk is soluble in muriatic acid at the common tem-
perature. When heat is applied the colour becomes brown. It
is soluble in nitric acid at the common temperature of the at-
mosphere, with the exception of a few flocks, which remain un-
dissolved. When heat is applied to the solution oxalic acid is
formed. In phosphoric and pyrophosphoric acids it is insoluble
at the common temperature of the atmosphere, but dissolves rea-
dily when the action of the acid is assisted by heat.
In weak potash ley it remains unaltered, but when the ley is
strong the fibrin dissolves in it by the assistance of heat. On
adding water to the solution the fibrin separates in flocks. Sul-
phuric acid also throws it^down in minute threads. It is very
remarkable that when this fibrin is precipitated from its solutions
it always assumes the form of minute threads. When mixed
with dry caustic potash and heated while the mixture is kneaded
together (unter kneten), it is converted into oxalic acid, as Gay
Lussac had already observed to have been the case with silk.
It is insoluble in carbonate of potash and in liquid ammonia.
When fibrin of silk is burnt in a platinum crucible a consi-
derable quantity of salt remains behind, which cannot be sepa-
rated from the fibrin till its texture is destroyed. This ash is
partly soluble in water, and the solution reacts weakly as an al-
kali. When muriatic acid was poured upon it, an effervescence
took place, and the whole was dissolved except a little silica.
The solution contained lime, iron, magnesia and soda ; manga-
nese, common salt, phosphoric acid, and sulphuric acid.
Mulder subjected this fibrin to analysis, and obtained,*
Carbon, . 47 -99
Hydrogen, . 6-57
Azote, . 17-35
Oxygen, . 28-09
100.
* Poggeridorf's Amialen, xl. 266.
200 ANIMAL AMIDES.
Mulder found that muriatic acid, combined with the fibrin of
silk, so as to form a compound of,
Muriatic acid, . 6-962 or 4-625
Fibrin, . . 93-038 or 61-671
If the two are combined atom to atom, the atomic weight will be
61-671, and the fibrin will consist of,
38 atoms carbon, . — 28-5 or per cent. 47-60
31 atoms hydrogen, — 3.875 ... 6-47
6 atoms azote, . =10-500 ... 17*54
17 atoms oxygen, . = 17-000 ... 28-39
59-875 100
Supposing fibrin of silk to be pure, and Mulder's analysis ac-
curate, it obviously differs in its composition from the fibrin
of blood. But the subject is too obscure to warrant any infe-
rence s.
SECTION VI. OF RICOTTIN.
This is a name given (ricotta) by the Italians to a substance
which exists in milk, but is not separated from the whey by ren-
net. In Switzerland it goes by the name of zieger, and in the
Vosges by that of bracotte. It has been examined by Schubler,
and is considered by him as intermediate between casein and al-
bumen. *
It may be obtained in the following manner : — Coagulate milk
by rennet and separate the whey. Raise the temperature of this
whey (after it has been filtered) to 167°, and mix it with acetic
acid. v A new coagulation takes place, and the ricottin is preci-
pitated. In Switzerland it is manufactured into a poor cheese,
which is said to be used in that country as food for cattle.
The characters of this substance, as given by Schubler, re-
semble so closely those of casein, that we can scarcely hesitate i
adopting the opinion of L. Gmelin, that ricottin is nothing else
than uncoagulated casein united to acetic acid.
Ricottin, in its fresh state, contains 84-4 per cent, of water. It
is a white, slimy, mucilaginous substance, very similar to albu-
men, not thready, and it has a specific gravity of 1 -055. Its taste
is that of albumen mixed with tallow. When dried it becomes
* Schubler, as quoted by L. Gmelin, Handbuch der Theoretischen Chemie,
ii. 1078.
4
GELATIN. 201
greyish-white, opaque, without lustre, hard, friable, and has a
specific gravity of 1*355. And when again moistened with wa-
ter, acquires the taste and smell of soap. The action of reagents
on it is the same as on casein.
CHAPTER II.
OF GELATIN.
THE term gelatin was introduced into chemistry to denote glue,
when deprived by a chemical process of all its impurities. The
name was contrived to point out the characteristic property of
pure glue. When put into water it swells up into a bulky gela-
tinous substance, but does not dissolve. When this jelly is heat-
ed up to 93° it dissolves in the water ; but the whole solution
assumes the form of a jelly when it is allowed to cool. It has
been shown by M. J. Miiller that there are two species of gela-
tin,— one which is not precipitated from its aqueous solution by
the addition of acetic acid, while acetic acid precipitates the whole
of the second species. As it is necessary to distinguish these two
species from each other, the first, which is obtained by boiling
skins and bones in water, is called common gelatin, or we may
give it the shorter appellation of collin* The second species,
which is obtained by boiling the permanent cartilages, has been
called chondrin by Miiller. We shall describe these two species
in succession.
SECTION I. COMMON GELATIN OR COLLIN.
Glue was well known to the ancients, and is said by Pliny to
have been first made by Daedalus, who lived in the time of Solo-
mon, or about 1000 years before the commencement of the
Christian era. It was applied by the ancients to the same pur-
poses for which it is used by the moderns. In this country it is
made from the clippings or parings of the skins of oxen, or other
large and full-grown animals. They are boiled in fresh water
till they are dissolved, and the liquid begins to get thick. It is
* From *e xx at, glue.
ANIMAL AMIDES.
then strained through baskets to separate the undissolved portions,
suffered to settle, and then farther evaporated till, on being pour-
ed into flat moulds, it concretes on cooling into solid gelatinous
cakes, which are cut in pieces, and dried on a kind of mat. In
France and Germany glue is made by boiling bones. Some
years ago Mr Yardley of Camberwell took out a patent for ex-
tracting glue from triturated bones, and contrived an ingenious
apparatus for the purpose. It is commonly believed that glue,
from ox hides, is stronger than that from bones. I have never
had an opportunity of comparing them together, so as to enable
me to judge of the validity of this opinion.
Glue consists chiefly of gelatin ; mixed, however, with various
impurities, which may be removed in the following manner : —
Put the glue into cold water. It gradually absorbs moisture,
and swells into a tremulous jelly, but does not dissolve. Pour
off this cold water once in twenty-four hours, and substitute a
new portion in its place till the liquid ceases to dissolve any thing
from the glue. Let it be now broken in pieces, and suspended
in a cloth in a great quantity of water of the temperature of about
60°. Any thing still soluble will be taken up by the water, and
the glue left nearly pure. If we now take this jelly and heat it
to 122°, it will become liquid, and may be passed through a cloth
or a filter, leaving behind it any coagulated albumen and mucus
which it may have contained. On cooling it again assumes the
form of a jelly, which may be dried in a low heat It is now
pure gelatin or collin.
Collin thus obtained is colourless, transparent, hard, and ex-
ceedingly cohesive. It is insipid, and has no smell. When
thrown into water it swells very much, and is converted into a
tremulous jelly ; but none of it dissolves. This tremulous jelly
becomes liquid when heated up to 93°, and again assumes the
gelatinous form on cooling.
From the experiments of Dr Bostock, we learn, that when one
part of isinglass (which is nearly pure gelatin) is dissolved in
1 00 parts of hot water, the solution on cooling is wholly convert-
ed into a jelly. But one part of isinglass, in 150 parts of water,
does not become concrete ; though the solution is to a certain de-
gree gelatinous.*
* Nicholson's Jour. xi. 250.
3
COL LIN. 203
Dry gelatin undergoes no change when kept ; but in the ge-
latinous state, or when dissolved in water, it very soon putrefies ;
an acid makes its appearance in the first place (probably the
acetic,) a fetid odour is exhaled, and afterwards ammonia is
formed.
When dry gelatin is exposed to heat, it whitens, curls up like
horn, then blackens, and gradually consumes to a coal ; but tre-
mulous gelatin first melts, assuming a black colour. When dis-
tilled, it yields, like most animal substances, a watery liquid im-
pregnated with ammonia, and a fetid empyreumatic oil ; leaving
a bulky charcoal of difficult incineration. It is by no means a
very combustible substance.
Collin is not sensibly soluble in alcohol,* and when alcohol is
poured into a warm concentrated solution, the whole gelatin coa-
gulates into a white, coherent, elastic, and fibrous mass, which
adheres strongly to glass, and gelatinizes in cold water, without
dissolving. Collin is likewise insoluble in ether and in oils both
fixed and volatile.
When a current of chlorine gas is passed through a solution
of gelatin in water, a white solid matter collects on the surface,
and whitish filaments swim through the liquid. This solid mat-
ter, when separated by the filter and purified, possesses the fol-
lowing properties ; its colour is white ; it is specifically lighter
than water ; it has little or no taste ; when dried in the open air
it falls to powder ; it is not soluble in boiling water ; it dissolves
in hot nitric and acetic acids, but precipitates again as the solu-
tion cools ; when triturated with potash it emits the smell of am-
monia ; it does not affect vegetable blues.f Bouillon La Grange,
to whom we are indebted for these facts, has given the gelatin
thus altered the name of oxygenized gelatin. It has been recently
examined by M. Mulder.J
When a current of chlorine gas is passed through a solution
of isinglass in lukewarm water, no change is apparent at first.
But in two or three minutes each bubble becomes surrounded
with a white substance, which adheres gradually to the sides of
the vessel as a white, elastic, and very cohesive substance. This
* Isinglass dissolves very well in rectified spirits. This property, together
with want of colour, distinguishes it from common collin.
f Bouillon La Grange, Nicholson's Jour. xiii. 209.
\ An", der Pharm. xxxi. 332.
204
ANIMAL AMIDES.
frothy-like substance increases more and more. The solution
becomes muddy from a small quantity of white flocks interposed
through it, while a gelatinous translucent substance collects on
the bottom of the vessel. The frothy substance, according to
Mulder, is a compound of four atoms of collin, and one atom
of chlorous acid, or 4 (C13 H10 Az2 O5) + Cr O3. The white
flocks are composed of C13 H10 Az2 O5 + Cr O3. The gela-
tinous substance at the bottom is 1^ (C12 H10 Az2 O5) + Cr O3.
This chloride of collin is insoluble in water and alcohol. It
reacts as an acid, and this property cannot be destroyed by wash-
ing it in warm water. It has also the smell of chlorine or rather
of chlorous acid. If we dissolve this chloride of collin by means
of ammonia, and put the solution into a glass tube standing over
mercury, azotic gas is slowly disengaged from it, and the whole
becomes a frothy mucus. If we evaporate the ammoniacal solu-
tion to dryness over the water bath, and mix the dry residue with
alcohol to extract a little sal-ammoniac which it contains, and
then dry the precipitate, we get a transparent matter of a pale-
yellow colour, which softens in water, melts when gently heated,
and gelatinizes imperfectly on cooling. It dissolves in a great
deal of water, and in its properties rather resembles gum than
gelatin, but reactives exhibit the same phenomena as with unal-
tered collin.
Chloride of collin becomes gelatinous in acetic acid, and dis-
solves in it. Water renders the solution muddy, but prussiate
of potash causes no precipitate, showing that no albumen has
been formed.
If we saturate the solution of chloride of collin with carbonate
of potash, and evaporate, we get a mixture of chloride of potas-
sium, and a small quantity of yellow matter.*
So far as is known, neither bromine nor iodine have the pro-
perty of combining with collin.
When collin is digested with concentrated sulphuric acid,
Braconnot has shown that it is converted into leucin, sugar of
collin, and a substance containing less azote than collin does.
Nitric acid, when digested with collin, causes the disengagement
of a little azotic acid gas, the collin is dissolved except an oily
matter, which swims on the surface, and converted partly into
* Berzelius, Traite de Chimio, vii. 706.
COLL IN.
oxalic and malic acids.* A quantity of artificial tannin is also
formed, and when the solution is evaporated to dry ness it de-
tonates.
Muriatic acid dissolves glue with great ease. The solution is
of a hrown colour, and still continues strongly acid. It gra-
dually lets fall a white powder. This solution precipitates tan-
nin in great abundance from water ; and may be employed with
advantage to detect tannin when an alkali conceals it.
Concentrated acetic acid softens and gradually dissolves col-
lin. The solution does not gelatinize, but the residue when
dried still retains the properties of collin. Dilute acids do not
prevent collin from gelatinizing on cooling, acetic acid does not
precipitate collin from its solutions.
The fixed alkalies dissolve collin with facility, especially when
assisted by heat. Dilute alkaline solutions added to liquid col-
lin do not prevent it from gelatinizing. The earths, barytes,
strontian, lime, and magnesia have no sensible action on collin,
at least they occasion no precipitate.
Collin combines with many salts. It dissolves a considerable
quantity of newly precipitated phosphate of lime. Alum does
not occasion a precipitate in solution of collin ; but if we add
an alkaline ley to the mixture, a copious precipitate falls, consist-
ing of collin combined with disulphate of alumina. The preci-
pitate resembles pure alumina : but if we heat it, we easily re-
cognize the presence of animal matter. Persulphate of iron does
not precipitate collin. But if we add to the persulphate enough
of ammonia to give it a deep red colour, and then mix it with
solution of collin, we obtain an abundant precipitate under the
form of a thick viscid, light-red clot.
Neither acetate nor diacetate of lead nor sulphate of alumina
occasion any precipitate in solution of collin.
If we mix by degrees solution of collin with that of corrosive
sublimate, a muddiness is produced which soon disappears.
This 'continues till we have added a certain quantity of the cor-
rosive sublimate. If we now add an additional quantity of this
reactive, the collin is thrown down under the form of a white clot,
which is coherent and very elastic. Similar precipitations are
obtained with nitrate of mercury and protochloride of tin. So-
lutions of silver and gold do not precipitate collin ; but when
* Scheele*; Crell's Annals, ii. 17. English Trans.
206 ANIMAL AMIDES.
the mixtures are exposed to the solar rays, a certain portion of
the metals is reduced. Sulphate of platinum precipitates collin
in brown viscid flocks, which become black in drying, and may
then be easily reduced to powder. Mr Edmond Davy, to whom
we owe the knowledge of this precipitate, informs us that it is
composed of
Peroxide of platinum, 56-11 or 14 = 1 atom.
Sulphuric acid, . 20-02 or 5 — 1 atom.
Collin and water, . 23-87
100-00
When the solution of tannin is dropped into collin, a copious
white precipitate appears, which soon forms an elastic adhesive
mass, not unlike vegetable gluten. This precipitate is composed
of gelatin and tannin ; it soon dries in the open air, and forms a
brittle resinous-like substance, insoluble in water, capable of re-
sisting the greater number of chemical agents, and not suscepti-
ble of putrefaction. It resembles exactly overtanned leather. The
precipitate is soluble in the solution of gelatin, as Davy first ob-
served. Neither is the whole tan thrown down, unless the solu-
tions both of tannin and gelatin be somewhat concentrated.
Tremulous gelatin, as was first observed by the same chemist,
does not precipitate tannin ; but if we employ a solution of gela-
tin so strong that it gelatinizes when cold, and heat it till it be-
comes quite liquid, it answers best of all for throwing down tan-
nin. It is by this property of forming a white precipitate with
tannin that gelatin is usually detected in animal fluids. It is not,
however, a perfectly decisive test, as albumen is also thrown down
by tannin. But collin is precipitated by tannin when in a much
more dilute state than albumen. A solution of one part of col-
lin in 5000 parts of water is sensibly precipitated by tannin.
When we mix a hot concentrated liquid solution of collin with
infusion of nutgalls, a white, curdy precipitate falls, which, if
there be an excess of tannin, forms a coherent elastic mass, which
constitutes a horizontal layer on the bottom of the vessel. It is
insoluble in water and alcohol ; though both of these liquids de-
prive it of a little tannin. When dry, it is black, hard, brilliant,
and breaks with a vitreous or rather resinous fracture. In water,
it softens and assumes its original appearance. According to
Davy, it is composed of
COLLIN. 207
Tannin, . 46 or 26-5
Collin, 54 or 31-1
100-
According to Schiebel, 26-8 of tannin combine with 22-36 of
collin, when 100 parts of collin are precipitated by a great ex-
cess of infusion of 1 part of oak-bark in 9 parts of water. When,
on the contrary, we mix a very dilute solution of oak-bark with
a solution of collin, taking care not to throw down the whole of
the collin, we obtain a precipitate, which is deposited slowly, and
can scarcely be separated by the filter. This precipitate is com-
posed of,
Tannin, . 59-25 or 26-5
Collin, . 100- or 44-72
It would seem from this that the first compound consists of
an atom of collin united to an atom of tannin, and the second of
two atoms of collin united to one atom of tannin. This would
make the atomic weight of collin, 22-36.
According to Mulder, neutral tannate of collin is composed of,
Tannin, • 10
Collin, . 13
23*
The first attempt to analyze collin was made by Gay-Lussac
and Thenard. They mixed it with chlorate of potash, and burnt
the mixture, and determined the products.! The result was as
follows :
Carbon, . 47-881
Hydrogen, . 7-914
Azote, . 16-998
Oxygen, . 27-207
100-000
\Vhat prevents us from drawing a satisfactory conclusion from
this analysis is our uncertainty about the purity of the collin,
examined. M. MulderJ has analyzed two specimens of collin,
which he purified in the following manner : The first specimen
• Ann. der Pharm. xxxi. 124. f Recherclies Physico-Chemiques, ii. 336.
\ PoggemlorPs Animlen, xl 279.
208 ANIMAL AMIDES.
was obtained by boiling pure hartshorn in water for two hours,
washing the jelly with alcohol, and then with water. In this
state, it left 5*406 per cent, of ashes; doubtless consisting of
phosphate of lime, which it is well known collin has the property
of dissolving. This specimen being subjected to analysis, was
found (abstracting the ashes) to be composed of,
Carbon, . 50-048
Hydrogen, 6-560
Azote, . 18-369
Oxygen, . 25 023
100-000
The second specimen of collin analyzed by Mulder was ob-
tained by boiling very pure isinglass for half an hour in water,
evaporating the solution by the water-bath, washing it with alco-
hol, and then drying it by a steam-heat. It contained 0-64 per
cent of ashes ; doubtless phosphate of lime. Its constituents
were,
Carbon, . 50757
Hydrogen, . 6-644
Azote, „ 18-313
Oxygen, . 24-286
100-000
A specimen carefully prepared from isinglass was analyzed in
Liebig's laboratory by Dr Scherer.* He obtained,
Carbon, . 50-557
Hydrogen, . 6-903
Azote, . 18-790
Oxygen, . 23-750
100-000
Four other analyses gave as a mean,
Carbon, . 50-573
Hydrogen, . 7-141
Azote, L ,>;$• 18-458
Oxygen, . 23-528
100-
* Ann. der Pharm. xl 46.
COLLIN. 209
He gives as the formula for its constitution, C48 H41 Az7£ O18.
If we calculate from this formula, we get,
48 carbon, = 36- or per cent. 49-83
41 hydrogen, = 5-125 ... 7-12
74 azote, = 13-125 ... 18-14
18 oxygen, = 18-000 .,. 24-91
72-25 100-00
These numbers agree tolerably well with the analyses ; but
they do not quite agree with the formula of Mulder, which will
be given immediately. Scherer's formula, reduced to Mulder's
numbers, would be, C15 H11 Az2 O5 ; while Mulder's is, C13
H10 Az2 O5 ; thus differing from Scherer's by an atom of hydro-
gen.
If we double the formula for collin we get, C96 H82 Az15 O36
If from these we subtract 2 protein, . C96 H72 Az12 O28
There remains . . H10 Az3 O8
This is equal to 3 (Az H3) + HO -f O7 or three atoms of
ammonia, one atom of water, and eight of oxygen.
Collin when dissolved in water and exposed to heat gradually
alters in its properties. Berzelius put a quantity of glue in a ge-
latinous state into a bottle, which was hermetically sealed. For six
successive days it was kept ten hours at the temperature of 176°.
During the remaining fourteen hours it was left to cool. It assum-
ed the form of a jelly less and less firm every day. After the
sixth day, it did not gelatinize at all. It was limpid and slight-
ly brownish. On opening the bottle, a little air entered. When
the liquid was evaporated, it left a transparent brownish mass so-
luble in cold water.* A similar set of experiments made by M.
L. Gmelin had the same result.
Gelatin, like all other constituents of animal bodies, is suscep-
tible of numerous shades of variations in its properties, and of
course is divisible into an indefinite number of species. Several
of these have been long known and manufactured for different
purposes : and many curious varieties have been pointed out by
Hatchett in his admirable Dissertations on Shell, Bone, and
Zoophytes, published in the Philosophical Transactions for 1797
and 1800. The most important species are the following:
* Traite de Chimie,
ANIMAL AMIDES.
Glue, — This well known substance has been long manufac-
tured in most countries, and employed to cement pieces of wood
together. It is extracted by water from animal substances, and
differs in its qualities according to the substances employed.
Bones, muscles, tendons, ligaments, membranes, and skins, all
yield it ; but the quality is best when skins are employed ; and
those of old animals yield a much stronger glue than those of
young animals. English glue is considered as the best, owing
to the care with which it is made. The parings of hides, pelts
from furriers, the hoofs and ears of horses, oxen, calves, sheep,
&c. are the substances from which it is extracted in Britain, and
quantities of these substances are imported for the purpose.
They are first digested in lime-water to clean them, then steeped
in clean water, laid in a heap till the water runs off, and then
boiled in brass caldrons with pure water. The impurities are
skimmed off as they rise ; and when the whole is dissolved, a lit-
tle alum or finely powdered lime is thrown in. The skim-
ming having been continued for some time, the whole is strained
through baskets, and allowed to settle. The clear liquid is gently
poured back into the kettle, boiled a second time, and skimmed
till it is reduced to the proper consistency. It is then poured
into large frames, where it concretes on cooling into a jelly. It
is cut by a spade into square cakes, which are again cut by
means of a wire into thin slices ; these slices are put into a kind
of coarse net- work, and dried in the open air.* The best glue is
extremely hard and brittle ; it has a dark brown colour, and an
equal degree of transparency without black spots. When put
into cold water, it swells very much, and becomes gelatinous, but
does not dissolve. When glue is soluble in cold water, it is a
proof that it wants strength. Dry glue, according to Dr Bos-
tock, contains 10^ per cent, of water.f
Size. — This substance differs from glue in being colourless
and more transparent It is manufactured in the same way, but
with more care ; eel skins, vellum, parchment, some kinds of
white leather, and the skins of horses, cats, rabbits, are the sub-
stances from which it is procured. It is commonly inferior to
glue in strength. It is employed by paper-makers to give
* Clennell. See Johnson's History of Animal Chemistry, i. 315,
j- Nicholson's Jour. xxiv. 7*
CHONDRIN.
strength to that article, and likewise by linen-manufacturers,
gilders, polishers, painters, &c.*
Isinglass. — This substance agrees with size in being transpa-
rent, but it is much finer, and is therefore sometimes employed
as an article of food. It is prepared in Russia from the air-blad-
ders and sounds of different kinds of fish which occur in the
mouths of large rivers ; chiefly different species of Accipenser, as
the Sturio stellatus, Huso ruthenus, and likewise the Siluris glanis.
The bladder is taken from the fish, clean washed, the exterior
membrane separated., cut lengthwise and formed into rolls, and
then dried in the open air. When good, isinglass is of a white
colour, semitransparent, and dry. It dissolves in water with
more difficulty than glue, probably because it is not formed ori-
ginally by solution. From the analysis of isinglass by Hatchett,
we learri that it is almost completely convertible into gelatin by
solution and boiling. Five hundred grains of it left by incine-
ration 1 -5 grain of phosphate of soda, mixed with a little phos*
phate of lime.
A coarse kind of isinglass is prepared from sea-wolves, por-
poises, sharks, cuttle-fish, whales, and all fish without scales. The
head, tail, fins, &c. of these are boiled in water, the liquid skim-
med and filtered, and then concentrated by evaporation till it ge-
latinizes on cooling. At that degree of concentration, it is cast
on flat slabs and cut into tablets. This species is used for clari-
fying, stiffening silk, making sticking-plaster, and other pur--
poses.f
SECTION II. OF CHONDRIN.
When any of the permanent cartilages of the body,J as those
of the larynx, ribs, or joints, are boiled from twelve to eighteen
hours in water, they dissolve more or less completely, and when
the solution is sufficiently concentrated, it gelatinizes precisely
like collin, and when dried constitutes a glue, which may be used
for all1' the purposes to which common glue is applied. It is,
therefore, a gelatin ; but it differs from collin by several proper-
ties first determined by M. J. Miiller, who gave it the name of
* Clennell. See Johnson's History of Animal Chemistry, i. 315.
f Fabricius de Ichthyocolla, Jackson on British Isinglass, Phil. Trans. Ixiii.
and Johnson's Animal Chemistry, i. 231.
\ The cartilages of the ear and the eyelids excepted, which yield no glue in,
forty-eight hours boiling.
ANIMAL AMIDES.
chondrin ;* and in 1841 a set of experiments, serving still farther
to characterize it, was published by M. Vogel, Jun.f It may be
distinguished by the following properties.
1. It is less brown than collin.
2. It is precipitated completely from its aqueous solution by
acetic acid, The precipitate is in very fine flocks, and gives the
liquid a white colour. It is not redissolved by an excess of acid ;
but if we neutralize the acid with carbonate of potash, the preci-
pitate is again dissolved. Acetic acid is incapable of throwing
down collin from its aqueous solution, or of rendering that solu-
tion muddy.
Vogel found that a similar precipitate was occasioned by most
of the mineral acids and organic acids tried. To precipitate by
sulphuric acid, we must employ a very small quantity of the acid.
If into half-an-ounce of the solution of chondrin we dip a rod
moistened with sulphuric acid diluted with six times its weight
of water, a precipitate falls. But the addition of a drop of the
acid redissolves the precipitate. Sulphurous acid precipitates
chondrin, and the precipitate is not redissolved by adding an ex-
cess of the acid. Nitric acid precipitates and readily dissolves
chondrin. This is the case also with phosphoric acid, but pyro-
phosphoric acid throws it down and an excess of the acid does
not redissolve the precipitate.
Phosphorous acid and fluoric acid precipitate chondrin, and the
precipitate is redissolved by an excess of the acids. A current
of carbonic acid long enough continued throws down the whole
of the chondrin, and does not again redissolve it. The precipi-
tate is a carbonate of chondrin.
The precipitates by arsenic, tartaric, oxalic, and citric acids
are not redissolved by an excess of these acids.
3. The aqueous solution of chondrin is precipitated by alum,
sulphate of alumina, acetate of lead, and persulphate of iron.
These reagents have no action on the aqueous solution of collin.
Alum or sulphate of alumina occasions the greatest precipitate.
It consists of white compact flocks, which speedily coalesce into
balls. The precipitate by acetate of lead or persulphate of iron
is in larger or smaller flocks, according as the liquid is more or
less concentrated. The addition of a small quantity of alum or
sulphate of alumina is sufficient to precipitate the whole chondrin
* Poggendoi-fs Annalen, xxxviii. 304. f Jour, de Pharm. xxxvii. 494.
3
CHONDRIN.
from its solution. The precipitate is insoluble in water, whether
cold or hot ; but an excess of alum or sulphate of alumina im-
mediately dissolves it. Hence, to precipitate chondrin completely
by these reagents, we must add them cautiously, and drop by
drop, to avoid any excess. The filtered liquor will not gelatinize,
and contains very little animal matter.
The precipitate by alum or sulphate of alumina is not redis-
solved by the addition of a little acetate of potash or of soda, or
of common salt ; but if a great quantity of these salts be added,
the precipitate is redissolved.
The precipitate by acetate of lead is not redissolved by an ex-
cess of the reagent. The precipitate by persulphate of iron is
abundant and bulky. It is not redissolved by an excess of the
reagent unless we apply heat, in which case solution takes place.
4. If to a solution of chondrin we add muriatic acid in very
minute quantity, not more than a fraction of a drop, the chondrin
is precipitated. A greater quantity of the acid not only does
not precipitate but redissolves what may have at first fallen.
Muriate of chondrin, (if we can give that name to a mixture of
solution of chondrin and muriatic acid,) is not precipitated by
prussiate of potash.
5. A very concentrated solution of chondrin is not precipi-
tated by caustic alkaline ley. But this ley precipitates collin ;
and the precipitate contains a great deal of phosphate of lime.
6. Chondrin is precipitated by chloride of platinum, but not
by nitrate of silver.
7. Alcohol throws down chondrin from a concentrated solu-
tion in white, consistent, thready flocks. If we filter off the al-
cohol the chondrin remains translucent and does not seem alter-
ed in its properties. For it dissolves in hot water and gelatinizes
as before. In this respect chondrin agrees with collin.
The alcohol will be found to have dissolved a small quantity
of a substance which is not chondrin. For it dissolves in cold
water, does not gelatinize, and is precipitated by tannin. These
are the . characters assigned to the principle distinguished by
Thenard by the name of osmazome, about which we at present
know very little.
8. The only known animal substance precipitated by acetic
acid besides chondrin is casein. But the two cannot easily be
confounded together. Casein does not gelatinize. Its acid so-
ANIMAL AMIDES.
lution is precipitated by prussiate of potash, but the muriate of
chondrin is not Muriatic acid precipitates casein, but dissolves
chondrin, and only occasions a precipitate when added in very
minute quantity.
9. Chondrin like collin is precipitated by tannin, chlorine, al-
cohol and corrosive sublimate.
Chondrin was subjected to an ultimate analysis by Vogel.
He states the constituents to be,
Carbon, . 48-97
Hydrogen, . 6-53
Azote, . 14*55
Sulphur, . 0-32
Oxygen, . 29-63
100-00
As we have no data to determine the atomic weight of chondrin,
we cannot state from this analysis the number of atoms which it
contains. Supposing the sulphur accidental, and the azote to be
three atoms, the composition would be C24 H19 Az3 O11. Hence
we see how much less azote it contains than collin.
The analysis of Mulder approaches pretty near to that of
Vogel.* He obtained,
Carbon, . 49-96
Hydrogen, . 6-63
Azote, . 14-44
Sulphur, . 0-38
Oxygen, . 28-59
100-00
He represents the constitution by the formula, C320 H260 Az40 S
O140 or 10 (C32 H26 Az4 O14) + S.
Dr Schererf analyzed chondrin from the cartilages of the
ribs. He obtained,
Carbon, . 50-195
Hydrogen, . 7-047
Azote, . 14.908
Oxygen, . 27-850
100-000
* Ann. der Pharm. xxviii. 328. f Ann. der Pharm. xl. 49.
CHONDRIN. 215
Chondrin from the cornea of the eye was found composed of,
Carbon,
49-522
Hydrogen, .
7-097
Azote,
14-399
Oxygen,
28-982
100-000
He represents it by the formula C48 H40 Az6 O20. Calculating
from this we get,
48 carbon, = 36 or per cent. 50-35
40 hydrogen, = 5 ... 7 '00
6 azote, =10-5 ... 24-68
20 oxygen, =20 ... 27 -97
71-5 100-
These numbers agree pretty well with the analyses. In compar-
ing the formula of Scherer with that of Mulder we must leave
out the sulphur which Scherer did not attempt to estimate. If
we reduce Scherer's formula to that of Mulder it will be C32 H27
Az4 O13, differing by an atom of hydrogen in excess and an atom
of oxygen deficient. If we adopt Scherer's formula, and compare
chondrin with protein we have,
Chondrin, . C48 H40 Az6 C20
Protein, . C48 H36 Az6 O14
H4 O6, which may be
represented by 4 (H O) -}- O2 ; or two atoms of water and two
of oxygen.
We cannot at present explain the cause of the different proper-
ties which collin and chondrin possess, though it must be connected
with the mode in which the elementary atoms are arranged in each.
There can be little doubt that chondrin as well as collin is an
amide ; but nothing is known respecting the acid, which may be
extracted from it, though it is probably the same as that from collin.
It will now be proper to point out the different textures of the
animal body which yield colliri and chondrin respectively. The
subject has been examined with care by J. Miiller and Schwann.
1. Skins give collin.
2. Tendons give collin.
3. The cornea of the eye gives chondrin.
216 ANIMAL AMIDES.
4. Elastic membranes ; for example the ligamenta flava of the
falx, the ligamentum hyothyroideum and cricotliyroideum me-
dium of the larynx, the ligaments of the larynx connected with
the voice, the middle coat of the arteries, &c. when hoiled suffi-
ciently long in water, give a glue possessed of peculiar charac-
ters ; but approaching nearer chondrin than collin. These mem-
branes have a yellow colour. They consist of fibres full of knots
and running into each other. They may be kept for years in
alcohol without losing their elasticity.
The glue from them is precipitated by acetic acid and acetate
of lead, though not to the same degree as chondrin. It is pre-
cipitated also by alum and sulphate of alumina. But persulphate
of iron does not occasion a precipitate, it only renders the liquid
opal coloured.
5. Fibrous cartilages, such as the cartilaginosiinarticulares, those
of the inter vertebral cartilages, those of the eyelids, likewise the
semilunar cartilages of the knee-joint of the sheep, give collin.
6. The spongy cartilages, viz. the cartilages of the ear, the
epiglottis, the appendages to the cartilagines arytenoidece in cat-
tle and swine, give various kinds of gelatin.
That from the cartilages of the ear differs from collin and
chondrin in this important respect, it does not gelatinize. The
glue obtained by boiling the sound of the cod also refuses to ge-
latinize, but dries into a hard brown substance, which may be em-
ployed to glue pieces of wood together. In chemical properties
the glue from spongy cartilages agrees with chondrin, excepting
that it is scarcely precipitated by acetic acid.
7. Permanent cartilages, such as those that attach the ribs to
the sternum or to each other, the cartilages of the joints, Sec-
yield chrondrin,
8. The cartilages of bones, obtained by removing the bone-
earth by an acid, yield collin, A great many were examined
by Miiller, and all yielded collin. Yet the same cartilages be-
fore ossification has taken place yield chondrin. It appears from
this that during ossification a change in the cartilaginous struc-
ture takes place* What tliis change is we have at present no
notion.
9* Permanent cartilages ossified by disease, yield collin.
10.. The cartilages of the teeth yield collin.
H. Fungous bones yield chondrin*
GELATIN FROM SILK. 217
12. Bones softened by osteomalacea yield neither collin nor
chondrin. When such bones are long boiled in water we obtain
an extract which is quite liquid, and does not gelatinize. When
filtered it has a brownish yellow colour. It is precipitated by
tannin and alcohol, but not by acetic acid, acetate of lead, or per-
sulphate of iron. Sulphate of alumina produces very little al-
teration on it, only a scarcely perceptible precipitate of flocks
redissolved by adding an excess of the reagent. Caustic potash
ley occasions no precipitate. These remarks apply to the very
highest stage of osteomalacea when the bones are quite flexible
and feeble.*
SECTION III. GELATIN FROM SILK.
This is probably the substance described by Hoard under the
name of yum.} Mulder first obtained it in a state of purity in
1836, described its properties, \ and subjected it to a chemical
analysis. § He obtained it from raw silk in the following man-
ner:
The silk was boiled successively in water till every thing solu-
ble in that liquid was taken up. The aqueous solutions were
evaporated to dryness, and the residue was treated with alcohol
and ether. What remained after the action of these liquids was
digested in hot water. The aqueous solution being evaporated
to dryness, the residue was considered as pure gelatin from silk.
It has a yellowish colour, is translucent, brittle, and destitute
of taste and smell. It is heavier than water, and is not altered
by exposure to the air. When heated in the open air it swells,
burns with flame, and leaves a bulky charcoal. When this char-
coal is consumed a white ash remains, consisting chiefly of car-
bonate of soda.
It is soluble in water ; but insoluble in alcohol, ether, fat and
volatile oils. The aqueous solution is very viscid ; it speedily
undergoes decomposition, giving out an ammoniacal odour. In
concentrated sulphuric acid it dissolves at the common tempera-
ture of the atmosphere without any change of colour. When
heat is applied the solution becomes black, and gives out a mixed
smell of caromel and sulphurous acid. In dilute sulphuric acid
* Muller ; Poggendorf's Anrmlen, xxxviii. 322. f Ann. de Chim. Ixv. 60..
t Poggendorfs Annalen, xxxvii. 606. § Ibid. xl. 284.
218 ANIMAL AMIDES.
it dissolves when assisted by heat When this solution is boiled
for some time the gelatin is converted into starch sugar. Nitric
acid dissolves the gelatin at the ordinary temperature of the at-
mosphere. When heat is applied deutoxide of azote is given
out and oxalic acid formed. In concentrated muriatic acid it
dissolves without any change of colour. In phosphoric acid it
dissolves, and if the solution be heated it blackens.
The solution in concentrated acetic acid forms when evaporated
a thick mass. When we mix it with water, no precipitate falls.
But prussiate of potash throws down a fine green precipitate,
which is soluble in water.
It dissolves in potash, soda, and ammonia, but is thrown down
by acids. The solution in acid is also precipitated by alkalies,
but the precipitate is again dissolved by adding an excess of po-
tash. We see from this that the gelatin is insoluble in solutions
of neutral salts with alkaline bases. It is soluble by boiling in
carbonate of potash. When acetic acid is added to this solution,
no disagreeable smell is evolved ; nor does the liquid become
black when silver is added to it.
When the aqueous solution is concentrated and set aside to
cool, it gelatinizes — a white precipitate falls, when the following
liquids are added to the aqueous solutions of this gelatin ; -alcohol,
infusion of nut-galls, protonitrate of mercury, diacetate of lead,
chloride of tin, chlorine water, bromine. The chloride of gold
throws down a yellow precipitate.
The following liquids occasion no precipitate when added to
an aqueous solution of gelatin : oxalic acid, acetate of lead, cor-
rosive sublimate, nitrate of silver, nitrate of cobalt, cyanodide of
mercury, perchloride of iron, chloride of barium, sulphate of
potash, iodide of sodium, sulphohydrate of ammonia, acetate
of copper, tartar emetic, borax, persulphate of iron. When iodine
is triturated with the aqueous solution of gelatin, no action is
perceptible,
It was analyzed by Mulder, who found its constituents (ab-
stracting 5-2 per cent, of ashes),
Carbon, . 49-49
Hydrogen, . 5*98
Azote, . 19-19
Oxygen, . 25-34
100-00
HEMTOSIN. 219
These numbers approach so near those obtained by analyzing
isinglass and common collin, that we cannot hesitate to consider
it as isomeric with these bodies.
CHAPTER III.
OF HEMATOSIN.
THIS name was given by Chevreul to the colouring matter of
blood, which Dr Wells,* as early as 1797, showed to be"an animal
substance of a peculiar nature. Vauquelin and Brande pro-
posed processes for obtaining it in an isolated state, but they did
not succeed in freeing it from the albumen with which, in the
crassamentum of blood, it is always united. Berzelius and En-
gelhart proposed other processes ; but what these chemists con-
sidered as hematosin was in reality a compound of hematosin and
albumen. And as the albumen greatly "preponderated in point
of quantity, the characters which they assigned to the colouring
matter were very nearly those which belonged in reality to al-
bumen. .
M. Lecanu, in his thesis published in 1837, has given the fol-
lowing process for obtaining pure hematosin.f Into human
blood deprived of its fibrin by agitation with a rod, pour sulphu-
ric acid, drop by drop, till the liquor, which assumes a brown
colour, coagulates into a thick magma. Dilute this magma with
alcohol, which causes it to contract in bulk. Put the whole into
a cloth, and subject it to sufficient pressure to squeeze out the al-
cohol together with the water formerly contained in the blood.
What remains in the cloth has a brown colour. It is to be re-
duced to small particles, and treated repeatedly with boiling al-
cohol, (the last portions of which must be acidulated,) till the li-
quid-ceases to assume a red colour.
The alcoholic solutions are left at rest till they are quite cold,
and then filtered to separate a quantity of albumen which will
have precipitated. The filtered liquid must be saturated with
ammonia, and then filtered again to get rid of some sulphate of
* See Phil. %g. xvi. 154.
f Etudes Chimiques sur le sang humain, p. 28.
220 ANIMAL AMIDES.
ammonia, which has precipitated together with a new portion of
albumen. The alcohol is now to be distilled off. What re-
mains is hematosin mixed with saline matter, some organic mat-
ter and some fat. Let it be successively treated with water, al-
cohol, and ether till it has been freed from everything solu-
ble in these three liquids. It is now to be digested in alcohol
containing about 5 per cent, of liquid ammonia. Filter again,
distil off the alcohol, and evaporate the residuum to dryness.
Wash what remains with distilled water, and dry it in a gentle
heat. It is pure hematosin.*
Hematosin thus obtained possesses the following properties :
It is solid, without taste and smell, and of a dirty brown colour,
provided it be obtained by the process above detailed ; but it has
the metallic lustre, and a reddish black colour when obtained
by evaporating an ammonico-alcoholic solution over the vapour
bath.
It is insoluble in water, alcohol of all strengths, sulphuric
ether, acetic ether, whether cold or hot.
Water, alcohol, and acetic ether, containing a very small quan-
tity of caustic ammonia, potash, or soda, dissolve it easily and
assume a blood red colour. But these alkalies never loose their
alkaline reaction, how great soever the quantity of hematosin may
be, which they may have dissolved.
Oil of turpentine and olive oil dissolve it when assisted by heat.
The solution has a fine red colour.
Alcohol slightly acidulated with sulphuric or muriatic acid
dissolves it readily. The solution is brown, but becomes blood-
red when the acids are saturated.
Alcohol of 0*8428, or still better, alcohol of 0-9212, dissolves
it when assisted by sulphate of soda. But this salt does not ren-
der hematosin soluble in water.
Water throws it down completely from its acidulated alcoholic
solution. The precipitate is pure hematosin, and contains no
acid. Water does not precipitate it from its ammoniaco-alco-
holic solution. When the solution is much diluted and boiled
for a long time, the hematosin is altered. It assumes a green-
ish tint, and becomes insoluble in ammoniated alcohol.
» Lecanu at first gave to the colouring matter of blood freed from albumen,
the name of globulin. But the observations of Gay Lussac and Serullas induced
him to abandon that term and adopt hematosin.
HEMATOSIN.
When the acidulous alcoholic solution is mixed with a solu-
tion of albumen in weak alcohol, and the acid is supersatu-
rated, the whole colouring matter precipitates with the albumen
in red flocks, which may be washed repeatedly in ammoniated
alcohol, without completely losing its red colour.*
When chlorine is passed through water holding hematosin in
suspension, this colouring matter is altered in its nature. White
flocks precipitate, which are insoluble in water, but soluble in al-
cohol ; while the liquid contains iron easily discoverable by the
usual reagents.
Concentrated sulphuric acid does not dissolve hematosin ; but
it deprives it of iron, and converts it into a black mass insoluble
in ammoniated alcohol and sulphuric acid. Very dilute suphu-
ric acid does not dissolve hematosin ; but it deprives it of iron,
and partly converts it into a new matter soluble in alcohol and
ether. The solutions have a red colour, and contain a good deal
of oxide of iron. Concentrated muriatic acid behaves almost
exactly like dilute sulphuric acid.
Concentrated nitric acid dissolves it, assuming a brown colour,
and quite altering the nature of the hematosin.
Mulder has lately examined the action of chlorhie on pure he-
matosin.f If we pass a current of chlorine gas through a mix-
ture of hematosin and water, the colour immediately disappears,
and the hematosin becomes white. The white flocks were collect-
ed on a filter and washed with water. On analysis they were
found to be a compound of the organic matter of hematosin and
chlorous acid. It had lost all its iron, which was found dissolv-
ed by muriatic acid in the aqueous solution. The liquid portion
contained, besides iron and muriatic acid, a little of the organic
matter which is not quite insoluble in that acid.
The flocks being dried at 284°, we found composed of
Carbon, . 37-34 or 44 atoms = 33
Hydrogen, . 3-01 or 22 atoms = 2-75
Azote, . 5-89 or 3 atoms = 5-25
Oxygen, . 24-34 or 24 atoms = 24-
'Chlorine, .' 29-42 or 6 atoms = 27-
100-00 92-00
* It was to this compound of hematosin and albumen that Lecanu gave the
name of globulin.
f Ann. der Pharm. xxxvi. 79.
222 ANIMAL AMIDES.
This is 1 atom hematosin, . C44 H22 Az3 O6
6 atoms chlorous acid, . 6(Ch O3)
When triturated with twice its weight of saltpetre, and thrown
into a red-hot platinum crucible, it is decomposed. The pro-
duct of the deflagration dissolves in water with the exception of
a little oxide of iron. The solution, when neutralized by nitric
acid, contains no sensible quantity of sulphuric or phosphoric
acid. Hence it follows that hematosin contains neither sulphur
nor phosphorus as constituents.
When hematosin is heated in a retort, it does not melt, but
gives out ammonia and an empyreumatic oil, and leaves a bril-
liant charcoal of small bulk, which, when charred, yields a quan-
tity of peroxide of iron. From 100 parts of hematosin Lecanu,
in four successive experiments, extracted ten parts of peroxide of
iron. Three of these portions of hematosin were obtained from
individuals aged about twenty-nine years, and that of the fourth
from an indhidual of eighty-three years of age. Now ten peroxide
is equivalent to seven metallic iron.
It is remarkable that iron is not separated from hematosin by
ammonia, potash, or soda ; nor is its presence indicated by tan-
nin or prussiafe of potash. It is difficult to conceive it to exist
in the state of oxide ; for if it did no reason can be assigned why
it is not acted on by these powerful reagents, which are so capa-
ble of detecting the presence of oxide of iron in ordinary cases.
Berzelius has suggested that it must exist in hematosin in the
metallic state. If we were to adopt this opinion, it would follow
as a consequence that the red colour of blood cannot be owing
to the iron which it contain?.
Hitherto hematosin and albumen have been considered as sub-
stances possessing very nearly the same properties ; doubtless, be-
cause the hematosin hitherto examined contained a notable quan-
tity of albumen. The following table, drawn up by M. Lecanu,
exhibits the differences between the two in a very striking point
of view :
Albumen. Hematosin.
Colourless, dull. Black, lustre metallic.
Soluble in water, unless coagulated. Insoluble in water.
Scarcely soluble in ammonia, slight- Very soluble in ammonia and po-
ly in weak potash ley. tasb, to which it gives a blood-red co-
lour.
HEMATOSIN.
Albumen. Hematosin.
Insoluble in alcohol and acetic ether, Very soluble in alcohol and acetic
amrnoniated or mixed with sulphuric, ether ammoniared or mixed with sul-
muriatic, or acetic acids. phuric, muriatic, or acetic acid.
Soluble in acetic acid, and in weak Insoluble in acetic, muriatic, and
muriatic and sulphuric acids, when as- sulphuric acids, whether weak or con-
sisted by heat. centrated.
Lecanu examined hematosin from human blood, and from
that of the ox, domestic fowl, duck, frog, carp, and mackerel,
and found it in all cases possessed of the very same properties.
The only difference observed was in the proportion of peroxide
of iron left when the hematosin was incinerated. Human hema-
tosin left 10 per cent., that of the ox left 12-76 per cent., while
that of the domestic fowl left 8 '34 percent
It seems not unlikely that the yellow, blue, and brown colour-
ing matters obtained by M. Sansen from blood, were hematosin
altered by the processes to which he had subjected it. His red
colouring matter evidently contained albumen.*
Hematosin was subjected to an ultimate analysis by Mulder,
by means of oxide of copper, f He obtained from the hematosin
taken from the arterial blood of oxen and sheep,
Carbon, . 64-57
Hydrogen, . 5-25
Azote, . 10-54
Iron, . 6*67
Oxygen, . 12-97
100-00
If we suppose the iron to amount to one atom, the constituents
of hematosin will be,
43 atoms carbon, = 32-25 or per cent 64-89
21 atoms hydrogen, = 2-625 ... 5-29
3 atoms azote, = 5-25 ... 10-70
1 atom iron, =3-50 ... 7-03
6 atoms oxygen, 603 ... 12-09
49-625 100-00
Mulder, to ascertain the atomic weight of hematosin, dried it
at the temperature of 266°, and passed a current of chlorine gas
over it till it refused to absorb any more. Nothing whatever
* Jour de Pharmacie, xxi. 420. f Annalen de Pharm. xxx'u 134.
ANIMAL AMIDES.
separated. The hematosin acquired a dark-green colour. He
obtained a compound of
Hematosin, . 66-19 or 8-78
Chlorine, 33-87 or 4-5
100-00
Now, if we suppose with Mulder that six atoms of chlorine
have combined with one atom of hematosin, the atomic weight
of this last substance must be 52-68, which approaches, though
not very nearly, to 49-625, the weight deduced from Mulder's
analysis.
Mulder has again repeated this analysis, and now considers
hematosin to be composed of C44 H23 Az3 O6Fe - 50-5.*
The compound of chlorine and hematosin is deep-green. It
dissolves in alcohol, communicating to that liquid the colour of
bile. Neither acids nor alkalies alter the colour of this solution.
But when boiled with potash, it becomes straw-yellow. When
heated with sulphohydrate of ammonia, the alcoholic solution be-
comes red.
Mulder did not succeed in combining iodine in definite quan-
tity with hematosin. When the compound was heated to 302°,
a temperature necessary to drive off the excess of iodine, the
whole of that substance escaped ; however, the hematosin was
altered, for it was insoluble in alcohol, mixed with ammonia or
with sulphuric acid.
When phosphorus or sulphate of iron is boiled with a solution
of hematosin, the colour is not altered. Boiling hot sulphuric
acid becomes coloured when mixed with hematosin ; but the
greatest part of this last substance remains undissolved ; yet its
nature is altered, for it is no longer dissolved when alcohol is
added. When sulphurous acid gas is passed through a solution
of hematosin in alcohol, acidulated with sulphuric acid, the co-
lour is not altered ; but when the solvent is ammoniated alcohol,
the colour becomes light-red.
When hematosin, dried at 266°, is put into dry muriatic acid
gas it assumes a violet red colour. The muriate formed dis-
solves in alcohol, and the liquid assumes a fine red colour. It
reacts as an acid. Mulder found that 100 parts of hematosin
absorbed 12-97 of muriatic acid. But when the compound was
* Ann. der Pharm. xxxi. 134, and xxxvi. 79.
IIEMATOSIN.
heated to 212*, 100 hematosin only retained 6.63 of muriatic
acid. Hence the first was composed of,
Hematosin, . 49.625 or 52.68
Muriatic acid, 6436 or 6-863
and the second of,
Hematosin, . 49-625 or 52-68
Muriatic acid, 3-29 or 3-493
The quantity of acid in the first compound was twice as great as
in the second. The first compound (if we reckon the atom of
hemafcosin 52*68) is composed of,
1 atom hematosin, . 52-68
1| atom muriatic acid, 6-9375
The second compound retains only three-fourths of an atom of
muriatic acid united to an atom of hematosin.
Hematosin combines with the metallic oxides as well as with
acids in definite proportions. Nitrate of silver being mixed with
an ammoniacal alcoholic solution of hematosin, and a little ni-
tric acid added, a dark brown precipitate falls. The filtered so-
lution is colourless, and neither contains iron nor colouring mat-
ter, the precipitate is a compound of hematosin and oxide of sil-
ver. 135 hematosin gave 22-55 of a mixture of 5-15 oxide of
silver, and 4-684 peroxide of iron. This compound is black,
has a glistening lustre, and burns like hematosin.
It combines in various proportions with oxides of copper and
lead. These compounds may be formed in the same way as that
of hematosin and oxide of iron.
From the preceding statement it appears that hematosin is
capable of combining in definite proportions, both with acids and
bases, though it does not neutralize either the one set of bodies
or the other.
Lecanu, as has been already stated, extracted 12-67 per cent,
of oxide of iron from ox blood. Mulder from the blood of
oxen and sheep, only obtained 9*6 per cent
Mulder has some speculations respecting the difference of he-
matosin in arterial and venous blood. He thinks it possible that
arterial hematosin may be, C43 H21 Az3 O6 + Fe
and venous, . C43 H21 Az3 O6 + Fe C
and that this carburet of iron is decomposed into iron and car-
bonic acid by the oxygen absorbed in the lungs.
ANIMAL AMIDES.
CHAPTER IV.
OF SPERMATIN.
THIS name has been given to what is considered as the essential
part of human semen. When emitted it is a translucent sub-
stance, swelled up, and having much the appearance of mucus,
only thicker, and frequently in cylindrical concretions. At first
it is insoluble in water : but after a certain time it becomes spon-
taneously liquid, and then dissolves or mixes readily with water.
This remarkable property distinguishes it from all other animal
substances.
When semen, at the instant of its emission, is let fall into alco-
hol of the specific gravity 0-833, it becomes opal coloured, it co-
agulates into a clot resembling a clue of pack-thread ; as if the
spermatin consisted of a long thread which had rolled upon it-
self in passing through the canal of the urethra. Thus coagu-
lated by alcohol it loses the property of liquefying by standing.
When dried it remains thready as before, has a snow white co-
lour, and is opaque. In water it gradually softens and assumes
the appearance of mucus, especially when boiled in that liquid ;
but very little of it dissolves. When the water in which it has
been boiled is evaporated to dryness, a white opaque matter re-
mains ; one portion of which is soluble in cold, and the remain-
der only in boiling water. Both solutions are abundantly pre-
cipitated by infusion of nut-galls. The portion of spermatin not
dissolved by the boiling water is equally insoluble in a weak so-
lution of caustic potash.
Spermatin coagulated by alcohol is soluble in cold sulphuric
acid, to which it gives a yellow colour. Water throws down the
portion dissolved white ; and the portion not dissolved contracts
when water is added and abandons the acid. The precipitate is
insoluble in water, even when assisted by heat.
Nitric acid while cold gives a yellow colour to spermatin, but
does not dissolve it ; when assisted by heat a solution takes place,
but the spermatin is again precipitated by the addition of water.
In concentrated acetic acid spermatin becomes gelatinous and
translucent. When the acid is raised to the boiling tempera-
ture solution takes place ; but the liquid still continues muddy,
from small undissolved threads remaining interspersed through
SPERMATIN. 227
it. The solution is precipitated by prussiate of potash; but not
by carbonate of ammonia nor corrosive sublimate. It is precipi-
tated also by infusion of nut-galls.
Spermatin coagulated by alcohol is softened in a concentrated
solution of caustic potash, but not dissolved, unless the action be
assisted by heat. The solution is not precipitated by acetic acid.
But if we supersaturate the liquid with this acid, evaporate to
dryness, and wash out the acetate of potash with alcohol, the ani-
mal matter remains undissolved. Water only dissolves it par-
tially, and the solution is precipitated by corrosive sublimate and
infusion of nut-galls.
The alcohol in which semen has been coagulated has an opal
tinge, and does not filter clear. When evaporated to dryness, it
leaves a residue which has the same properties as that left by
water in which the semen has coagulated.
When the semen falls into water at the instant of its emission,
it coagulates pretty much as in alcohol, constituting a white fi-
brous mass, which, on the least touch, separates into threads, and
when taken out of the water, dissolves in acetic acid. The solu-
tion is copiously precipitated by prussiate of potash. If these fi-
laments are left in water, they gradually dissolve and disappear
except a few threads, which subside very slowly. When these
are separated by the filter and the watery solution evaporated,
it exhales for a long time the peculiar smell of semen, becomes
opal-coloured, and when evaporated to dryness, leaves a trans-
parent varnish, scarcely visible, at the bottom of the vessel.
Water softens this varnish, and dissolves a little of it, which gives
it a yellow colour. When we evaporate this solution and treat .
the residue with absolute alcohol, a portion is dissolved, which,
when freed from alcohol, has the form of a yellow extract, which
reddens litmus-paper.
Cold water dissolves very little of the matter on which the al-
cohol does not act. But boiling water takes up more, and leaves
a yellowish-brown and very mucous matter. The aqueous solu-
tions, whether hot or cold, have the same properties. When
evaporated to dryness, they leave a yellowish transparent matter,
having the smell of toasted bread and a peculiar taste. Water
makes it white and mucous, and dissolves it rapidly. The solu-
tion is precipitated by acetate of lead, protochloride of tin, cor-
rosive sublimate, nitrate of silver, and infusion of nut-galls.
ANIMAL AMIDES.
The portion insoluble in boiling water is not dissolved by ace-
tic acid. It is partially dissolved in cold potash ley.*
CHAPTER V.
OF SALIVIN.
SALIVIN or ptyalin, as it is also called, is a peculiar substance
which exists in human saliva. It seems to have been first no-
ticed by Dr Bostock in 1805, who describes it under the name
of pure mucusj It is not described by Berzelius in the second
volume of his Djurkemien, published in 1808. But in his paper
on the Chemical Properties of Animal Fluids, published in 1813,
it is particularly noticed under the name Salivary, or peculiar Ani-
mal Matter. \ More lately its properties have been examined by
Tiedemann and L. Gmelin.§ Salivin may be obtained in the
following manner :
Evaporate saliva to dryness in a gentle heat. Digest the re-
sidual mass in rectified spirits, which dissolve most of the salts
of saliva. An additional portion of alcohol acidulated with ace-
tic acid will remove any soda that might still remain. Nothing
now remains but a mixture of salivin and mucus. Water dis-
solves the former of these substances, and leaves the mucus. The
aqueous solutions being evaporated in a gentle heat, leaves pure
salivin.
Thus obtained it is a transparent white substance, which does
not crystallize, and is destitute of taste and smell. It is not al-
tered by exposure to the air. It dissolves readily in water, but
is insoluble in alcohol. The aqueous solution is not precipitat-
ed by alkalies or acids, nor by solutions of diacetate of lead, ||
corrosive sublimate, or of tannin. It does not become turbid on
boiling, and does not gelatinize when the concentrated solution
is allowed to cool. The only substances which precipitate it from
its aqueous solution are alcohol and nitrate of silver. And this
* Berzelius, Trait6 de Chimie, vii. 558.
t Nicholson's Jour. ii. 251. \ Annals of Philosophy, (1st series,) ii. 380.
§ Recherches Experimen tales, i. 12.
|| Bostock obtained a precipitate with this salt because his salivin contained
uncombined soda.
PEPSIN.
last precipitate is soluble in ammonia. Salivin is not precipitat-
ed by chlorine.
When salivin is charred, ammonia is given off, and the coal
contains potash and soda,
Salivin from neutral saliva does not act as an alkali, but
slightly as an acid. If the saliva be not previously neutralized,
reddened litmus-paper, when dipt into it, becomes, blue. The
colour of the salivin is yellowish-brown when the alkali of the
saliva is not neutralized, and it absorbs moisture from the air.
CHAPTER VI.
OF PEPSIN.
THIS name, (from vwrgig, digestion,) was given by Dr
Schwann of Berlin* to a substance which constitutes an essential
portion of the gastric juice, as without its action many articles of
food could not be converted into chyme in the stomach. All
articles of food containing coagulated albumen, fibrin, and (to
a certain extent also) casein, f To make an .artificial gastric
juice capable of dissolving these substances, the inner coats of
the third and fourth stomachs of an ox were digested for twenty-
four hours in water containing a mixture of 2 J per cent, of mu-
riatic acid of commerce. After this digestion (without heat) the
liquor was filtered. It contained in solution 2*75 per cent, of
solid matter, and required rather more than 2 per cent, of carbo-
nate of potash to neutralize it. When this liquor was digested
for several hours on coagulated albumen, (at the temperature of
98*,) in powder, it dissolved it completely.
Muller's experiments showed that the mere acid solution will
not dissolve coagulated albumen ; and Eberle and Schwann found
that the same acid solution, after the ox's stomach was digested
in it, has acquired the property of dissolving albumen. Hence
something is taken up from these stomachs which gives the acid
liquid the property of dissolving albumen and fibrin. It is to this
something that the name of pepsin has been given.
The following are the facts respecting this principle which
* Poggendorf's Annalen, xxxviii. 358.
t The chymosin of Deschamps is obviously the same with pepsin. See Jour,
1« Pharm. xxvi. 412.
230 ANIMAL AMIDES.
have been determined, and for which we are chiefly indebted to
Dr Schwann :
1. When the pepsin solution is neutralized by potash, nothing
is precipitated ; but its digesting properties are destroyed.
2. Though the pepsin solution be much diluted with acidulat-
ed water, its digesting powers are not injured, but it cannot be
diluted with pure water without the destruction of these powers.
3. The quantity of acid necessary for the digestive properties
of the liquid continuing, is regulated not by the pepsin present,
but by the water. The muriatic acid of commerce present must
amount to 2J per cent.
4. When food is dissolved in this acidulated liquor, none of
the acid is saturated. The quantity still uncombined is the same
as at first.
5. If we neutralize the solution, evaporate it to dryness in a
low temperature, and digest the residue in alcohol, the digestive
properties are destroyed.
6. If the pepsin liquor be heated to the boiling point, its di-
gestive properties are destroyed.
7. When acetate of lead is dropt into the pepsin solution, the
pepsin is precipitated in combination with the oxide of lead, and
the precipitation is more complete if the liquor has been previous-
ly neutralized. Pepsin is precipitated also from its neutral so-
lution by corrosive sublimate, but not by prussiate of potash.
8. But the most characteristic action of pepsin is its coagulat-
ing milk, and throwing down the casein. When one part of pep-
sin solution is mixed with 238 parts of milk, the whole is coagu-
lated. The quantity of muriatic acid of commerce necessary to
produce the same effect is 3-3 per cent.
The neutralized pepsin solution still coagulates milk, but if its
temperature be raised to the boiling point, this property is de-
stroyed.
9. Pepsin and casein may be reciprocally used as reagents for
each other. A liquid containing only 0-0625 per cent, of casein
is precipitated by the neutral pepsin solutions. This delicate ac-
tion on casein is the most characteristic property of pepsin
hitherto observed, and puts it in our power to distinguish it from
other substances, especially from mucus, with which, from some
of its properties, it might otherwise be confounded.
10. The small quantity of pepsin which causes the solution of
PEPSIN.
albumen is remarkable. Acidulated water, holding in solution
only O25 per cent, of pepsin, shows a decided action on albu-
men. 98 grains of water acidulated with muriatic acid, and con-
taining only 4-8 grains of the solution of pepsin, dissolves 49
grains of albumen in twenty-four hours at the temperature of
9 9°. 5. Now as 4 '8 grains of the digesting liquor contain only
Oil grain of solid matter, it follows that one grain of pepsin is
capable of causing the solution of at least 100 grains of dry al-
bumen.
11. When pepsin liquor is employed to dissolve albumen, it
partly loses its digestive power. Hence it must suffer an alte-
ration during the process.
12. It acts best at the temperature of 100°, but it will act also
at 54° or 55°, though not so well.
M. Wasmann has succeeded in obtaining pepsin in an isolated
state by the following process :* He separates the glandular
membrane of the stomach without cutting it, washes it, and
digests it in distilled water at a temperature between 86°
and 95°. After several hours, he decants off the liquid, and
washes the membrane again in cold water till it gives out a pu-
trid smell. The waters are mixed and filtered. The liquid thus
obtained is transparent, a little viscid, and possessed of a strong
digestive power, when a little muriatic acid is added to it. To
separate pure pepsin from it, acetate of lead is added, the pre-
cipitate washed, mixed with water, and decomposed by sulphu-
retted hydrogen. The liquid separated anew is fluid, colourless,
and acid. When, after having evaporated that liquid to the con-
sistence of a syrup, in a temperature which must not exceed 95°,
we pour absolute alcohol into it, a copious flocky precipitate falls,
which, being carefully dried, is a yellow gum-like substance, which
does not attract moisture from the atmosphere.
Pepsin is soluble in water, which it makes acid, because it re-
tains obstinately a little acetic acid. The solution, though it
contained no more than ^oo-th of pepsin, dissolves in six or eight
hours white of egg slightly acidulated : but it loses its digestive
properties when boiled or saturated with potash. In the last case,
it deposites flocks which are insoluble in water, but dissolve slow*
ly in dilute acids, constituting feebly digestive liquids.
We recognize pepsin by the precipitates thrown down by di«
* Jour, de Pharm. xxvi. 481.
232 PARTS OF ANIMALS.
lute acids from its solution, and which are again redissolved by
an excess of the acids. It is distinguished from albumen by the
precipitates produced by acetic acid and muriatic acid in its
aqueous solutions, and from casein, because prussiate of potash
does not precipitate its acid solutions.
A concentrated solution of pepsin is thrown down by corrosive
sublimate and acetate of lead, but the precipitates are redissolved
by adding an excess of the reagent, and also by acetic and mu-
riatic acids. The sulphates of iron and the protochloride of tin
also precipitate pepsin ; and all the precipitates by metallic solu-
tions possess digestive properties.
When burning, pepsin gives out the odour of burning horn,
and leaves a charcoal difficult to incinerate, in which is found
lime, soda, phosphoric acid, and a little iron.
CHAPTER VII.
QF PANCREATIN.
THIS substance was detected in the pancreatic juice of the
dog by Tiedemann and L. Gmelin, but they did not obtain it in
a separate state. The only characteristic property of it which
they ascertained is this : it is coloured red by a small quantity
of chlorine, and discoloured by a small quantity.
DIVISION II.
OF THE PARTS OF ANIMALS.
THE different substances which compose the bodies of animals
may be divided into two classes, namely, 1st, the solid parts, such
as bones, muscles, skin, &c. of which their bodies are made up ;
2d, the fluid parts. Some of these, as the chyle and blood, are
intended for the nourishment of the living being ; others, as sa-
BONES. C233
and bile, are secreted to answer important purposes in the
animal economy ; others, as the urine, are separated from the
blood to be thrown out of the body as useless to the system ; and
others, as milk, for the nourishment of the young animals. To
these may be added certain foreign substances which make their
appearance in various parts of the body in consequence of dis-
ease. These being usually solid bodies have received the name
of morbid concretions. This important division will therefore be
divided into three parts, namely, 1. The Solid Parts of Animals ;
2.The Liq uid Parts ; and 3. Morbid Concretions.
PART I.
OF THE SOLID PARTS OF ANIMALS.
THE solid parts of animals are very numerous, and many of
them hitherto have scarcely been examined. The following chap-
ters contain a general view of such of them as have hitherto
come under chemical investigation.
CHAPTER I.
OF BONES.
BY bones are meant those hard, solid, well-known parts to
which the firmness, strength, and shape of living animals are in
some measure owing. In man, quadrupeds, and most other ani-
mals, the bones are situated below the other parts, and scarcely
any of them are exposed to view ; but in some of the tribes of
the lower animals, as the Conchifera and Mollusca, the bony por-
tion is placed on the outside of their bodies, evidently for de-
fence; In this case, they are distinguished by the name of shells.
In other animals, as lobsters and crabs, the external bony cover-
ing is called a crust. We shall treat of bones in the present
chapter, and of shells, crusts, and zoophytes afterwards.
The bones in a human skeleton of mature age amount to about
200, not reckoning the teeth; but in extreme youth they are
234 SOLID PARTS OF ANIMALS.
more numerous ; because various bones, at first separate, gra-
dually unite into one as the age of the individuals advances.
They are very various in their shape. Some, as the shoulder-
bone, the thigh-bone, &c. are long and hollow ; others, as those
of the cranium, are flat and thin ; while others, as those of the
wrist and heel, are short and solid, or nearly so. They are cover-
ed by an external membrane, which adheres to them closely, and
called the periosteum. The external cavity of the long bones is
also lined with a periosteum, from which many of the vessels des-
tined to nourish the bones originate. The flat bones are hard
and dense at the surface, but interiorly they have a kind of ca-
vity divided into innumerable cells by means of thin bony parti-
tions.
When bones are stripped of their periosteum by long boiling,
they are white, if from a healthy animal. When the animal has
been diseased, the bones frequently have a shade of yellow. The
specific gravity varies a little : that of the blade-bone or scapula
of an ox is 1-656, as determined by Mr John Caswell.*
The following little table exhibits the specific gravity of various
bones as determined by me :
Os femoris of a sheep, . . 2-0345
Tibia of sheep, . . . 2-0329
Ileum of an ox, . . . 1*8353
Human os humeri, . . . 1-7479
Vertebra of haddock, . . 1-6350
First phalanx of human great toe, . 0-9775
As the age of these bones was unknown, it is impossible to draw
any general inference from these experiments. The lightness of
the bone of the great toe was obviously owing to the cavity with-
in. When boiled in water, they do not lose their shape, but a
quantity of collin is separated, and likewise a portion of fatty
matter. Alcohol and ether, when digested on bones, also dis-
solve a quantity of fatty matter. When left in contact with mu-
riatic acid the earthy matter of bones dissolves, and a cartilage re-
mains, soft and flexible, but retaining nearly the shape and bulk
of the original bone. When this cartilage is boiled for a long
time in water, it is dissolved and converted into collin, with the
exception of a small portion of fibrous-looking matter, which still
» Phil. Trans. 1693, xvii. 694.
BONES. 285
remains, and which Berzelius assures us consists of the small
blood-vessels which traversed the bone in order to supply it with
nourishment.
The fact that muriatic acid deprives bones of their earthy
matter, leaving only cartilage, was not unknown to chemists at
an early period. It is mentioned by Boerhaave as well-known
in his time.* It had also been long observed that when bones
are heated in an open fire they burn with flame, and leave a
white, brittle, friable substance, having the shape of the original
bone, but much lighter, and distinguished by the name of earth
of bones. In some of the earlier systems of chemistry, the earth
of bones is considered as a substance sui generis, and ranked
among the earths. About the year 1768, Assessor Gahn of
Fahlun discovered that this supposed earth consisted chiefly of
phosphate of lime. Scheele, in his experiments on fluor spar,
published in 1771, mentions, when giving an account of the ac-
tion of phosphoric acid on fluor spar, that it had been lately dis-
covered that the earth of bones was phosphate of lime.f In con-
sequence of this notice, it was for some time believed that Scheele
was the discoverer of the constitution of bone-earth ; and Asses-
sor Gahn was so indifferent about his reputation as a discoverer,
that he never tried to correct a mistake, which had been so long
prevalent.
The first person that attempted an analysis of bone was Me-
rat-Guillot, an apothecary at Auxerre, who, about the year
1 798, published a comparative analysis of the bones of man, and
of a variety of other animals ;J but his results were far from
near approximations to the truth. About the year 1801, Four-
croy and Vauquelin announced the discovery of phosphate of
magnesia in bones, and published an analysis of the bones of an
ox.§ In 1808, Berzelius published the second volume of his
Animal Chemistry, in which he gave an analysis both of hu-
man bone and that of the ox.|| Morichini had announced a year
or two- before that fossil bones contained fluoric acid in combina-
tion with lime, and this discovery was confirmed by the experi-
ments of Gay-Lussac.1T Berzelius, in his elaborate analysis of
* Boerhaave 's Chemistry, i. 518 ; English translation.
f Scheele's Essays, p. 13; English translation.
\ Ann. de China, xxxiv. 68. § Ibid, xlvii. 244.
|| Djurkemie, ii. 120. f Phil. Mag. xxiii. 264, or Ann. de Chim. lv. 258.
236 SOLID PARTS OF ANIMALS.
bones, published in 1806,* announced the existence of fluate of
lime in fresh bones ; but this discovery has not been verified by
other experimenters. Dr Wollaston tried in vain to extract
fluoric acid from recent bones ; and unless I have been misinform-
ed the same want of success attended the researches of Mr Brande
upon the same subject. In 1829, M. Denis published a compa-
rative analysis of human bones from subjects of very different
ages.f About the same time M. D'Arcet pointed out the quan-
tity of nourishment which bones contain, and the best method of
extracting itj The investigations of Muller in 1836, on the
structure and chemical properties of the animal matter in bones
and cartilages,§ have added considerably to our knowledge of a
set of bodies highly worthy of a more accurate and complete in-
vestigation than they have hitherto met with.
1. If we leave a bone in dilute muriatic acid at the common
temperature of the atmosphere, the earthy salts are gradually
dissolved, and the acid may be removed by keeping the bone
for some time in water, which must be renewed till it comes off
from the solid residue of the bone quite tasteless. What remains
is now the cartilage. It has the size and shape of the original
bone ; but is soft, elastic, and translucent, and has a yellowish
white colour. When dried the cartilage diminishes somewhat in
bulk, though it retains its translucency. It is hard and brittle,
and assumes very much the appearance of horn.
From the microscopic observations of Purkinje and Deutsch, ||
it appears that when the cartilage from a long bone is examined
it consists of a congeries of long minute tubes filled with marrow.
These tubes, according to Muller, consist of very fine circular
plates, and the intervals between them are filled up by numerous
circular plates which encircle the tubes. These plates may be
separated from each other by macerating the cartilage for a long
time in water. Besides these marrow tubes the cartilage con-
tains numerous scattered oval-shaped particles, the length of
which varies from 0-0004 to 0-0006 inch, and their breadth from
0-00014 to 0-00025 - inch, according to the measurement of
Miescher. These particles usually lie so that their length is
* Afhandlingar, i. 195. t J°ur. de Physiologic, ix. 183.
\ Jour, de Pharmacie, xv. 236. § Poggendor£s Annalen, xxxviii. 295.
II Muller, Poggendorfs Annalen, xxxviii. 296.
BONES. 237
parallel to that of the marrow tubes. They are rather more
opaque than the concentric plates which surround the marrow
tubes. Whether they be solid or perforated has not been de-
termined. In the cartilages of the ribs these particles are very
irregular in their position.
The weight of cartilage in the long bones varies from 28 to
33 J per cent. It is very difficult to prevent a portion of it from
being dissolved by the muriatic acid employed to remove the
earthy salts of the bone. The best way is to take care that the
acid be very dilute . When the cartilages of bones are boiled a
sufficient time in water they are converted into collin, while the
permanent cartilages of the body by the same treatment become
chondrin. It is obvious from this that there is a difference be-
tween the cartilages of bones and the permanent cartilages,
though in what that difference consists we cannot at present spe-
cify. It has been already stated, on the authority of Berzelius,
that when the cartilage is thus converted into collin or chondrin
the blood-vessels of the bones remain undissolved, and fall to the
bottom of the liquid under the form of delicate fibres.
2. The other constituent of bone is the earthy salts, which are
gradually deposited in the cartilage as the age of the animal ad-
vances. The bones of the foetus, at a certain interval before
birth, are all cartilage. At birth they are partly bone and part-
ly cartilage. The ossification goes on progressively, and in old
age only those permanent cartilages retain their nature which
are necessary for the maintenance of life and motion ; as the
cartilages of the ribs and those that tip the articulating bones.
The earthy salts are held in solution by the muriatic acid.
From the effervescence which attends the action of muriatic acid
on bones, it is obvious that one of these salts is a carbonate.
And as calcined bones contain carbonate of lime, there is no
reason to doubt that carbonate of lime constitutes one of the
earthy salts which exists in bones.
If we saturate the muriatic acid solution with caustic ammo-
nia, adding an excess of that alkali, the phosphate of lime
precipitates and may be collected on the filter. It constitutes
more than one-half of the weight of the bone subjected to ana-
lysis.
If we now add carbonate of ammonia to the liquid which has
238 SOLID PARTS OF ANIMALS.
passed through the filter, the carbonate of lime will be thrown
down, and may be collected on a filter. The liquid still contains
magnesia, which was prevented from falling by the excess of am-
monia jised, or rather of sal-ammoniac formed, which, constitut-
ing with the magnesia a double salt, prevented it from falling
down when the carbonate of ammonia was added.
Let the residual liquid be evaporated to dryness and the resi-
due exposed to a strong heat. The 'magnesia will remain near-
ly pure. But it is mixed with a little common salt. Water
dissolves the common salt and leaves the magnesia. In this
way may all the constituents of the earth of bones be separated
from each other. They consist of
Subsesquiphosphate of lime,
Carbonate of lime,
Magnesia,*
Common salt,
Probably the common salt in the bone may have been partly in
the state of soda.
Berzelius analyzed human and ox bones, having first deprived
them of all the fatty matter or marrow which they contained,
and also having freed them from their periosteum. The follow-
ing are the results which he obtained :
Human. Ox.
Cartilage soluble in water, 32-171 QQ on
Vessels, . MS/
Subsesquiphosphate of lime, 53*04 5 7 '35
Carbonate of lime, . 11-30 3-85
Phosphate of lime, . 1-16 2-05
Soda with a very little common salt, 1*20 3-45
100-00 100-00
From the experiments of Dr Rees,f it appears that the pro-
portion of cartilage and earthy matter differs somewhat in dif-
ferent bones. The following are the proportions in different
human bones of an adult :
* The magnesia is not in the state of phosphate, as Fourcroy and Vauquelin
supposed ; otherwise it would have been precipitated by the caustic ammonia.
It may have been in the state of carbonate.
f Medico- Chirurgical Transactions, Vol. xxi.
BONES. 239
Earthy matter. Cartilage.
Femur, . . 62-49 . 37-51
Tibia, . . 60-01 . 39-99
Fibula, . . 60-02 . 39-98
Humerus, . . 63-02 » 36-98
Ulna, . . . 60-50 . 39-50
Radius, . . 60-51 . 39-49
Squamous portion of temporal bone, 63-50 . 36-50
Vertebra, (arch of dorsal), . 57-42 . 42-58
Rib, (external crust), . 57*49 . 42-51
Clavicle, . . 57-52 . 42-48
Eeum, (near the crest), . 58-79 . 41-21
Scapula, (coracoid process), . 54-51 . 45-49
Sternum, . . 56-00 . 44-00
Metatarsal bone of great toe, 56*53 . 43-47
The cancellated structure of various bones gave the following
results :
Earthy matter. Cartilage.
Head of femur, . 60-81 . 39-19
Rib, . . 83-12 . 46-88
Solid portion of ditto, 57-77 . 42-23
Dr Rees examined also the bones of a foetus, and obtained the
following result :
Earthy matter. Cartilage,
Femur, . 57-51 . 42-49
Tibia, . 56-52 . 43-48
Fibula, . 56-00 . 44-00
Humerus, . 58-08 . 41-92
Radius, . 56-50 . 43-50
Ulna, . 57*49 . 42-51
Clavicle, . 56*75 . 43-25
Ileum, . 58-50 . 41-51
Scapula, . 56-60 . 43*40
Rib, . 57-35 . 42-65
Parietal bone, . . 55-90 . 44-10
The following analyses were made by M. Denis. He does not
notice magnesia, but perhaps it may be included in the carbo-
nate of lime :
240 SOLID PARTS OF ANIMALS.
Radius of a girl Do. of Do. Do. of Do.
aged 3 years. aged 20. aged 78. '
Water with a little grease, . 33-34 . 13 . 15-4
Cartilage, . 33-34 . 27-8 . 27-9
Phosphate of lime, . 23-32 . 53-0 . 43-9
Carbonate of lime, . 10 . 6-2 . 12-8
100-00 100-0 100-0
Ox bones were analyzed by Fourcroy and Vauquelin, who stated
their constituents to be,
Cartilage, . 51-0
Phosphate of lime, 37*7
Carbonate of lime, 10-0
Phosphate of magnesia, 1*3
100-0
Lassaigne analyzed the callus of a broken bone with the dif-
ferent sound parts of the bone in its neighbourhood, and obtained
the following results :
Callus; Ditto. Sound Ditto. Sound part Exos-
outer side, inner side. bone, thickened. in do. tosis.
Animal matter, 50-0 48.5 40- 43- 41-6 46-
Soluble salt, 11-3 12-8 12-4 14-2 8-6 10-
Carbonate of lime, 5-7 6-2 7-6 6'5 8-2 14-
Phosphate of lime, 33-0 32-5 40-0 36-3 41-6 30.
100-0 100-0 100-0 100-0 100-0 100-
According to Berzelius's analysis, the proportion of carbonate of
lime is much greater in the human bone than in that of the ox. But
the analysis of Fourcroy and Vauquelin gives a different result.
The following table by Fernandez de Barros shows the relative
quantities of phosphate and carbonate of lime found in the ashes
of the bones of various animals :*
Phosphate of lime. Carbonate of lime.
Lion, 95' . 2-5
Sheep, 80- . 19-3
Fowl, 88-9 . 10-4
Frog, 95-2 '. 2-4
Fish, 91-9 , 5-3
Berzelius analyzed the ashes of human bones, (we do not know
of what age,) and found them composed of,
* Berzelius, Traite de Chimie, vii. 475.
BONES. 241
Human. Ox.
Phosphate of lime, 81-9) gg, QQ.*
Fluate of lime, . 3-0 /
Lime, . 10-0 9-3 1-45
Magnesia, . . 0-3 1*10
Phosphate of magnesia, 1*1
Soda, . 2-0 2-0 3-75
Carbonic acid, . 2-0 2-0 3-
190-0* 100-0 100-0
The loss in the analyses varied from 1 to 1 J per cent The
proportions varied somewhat in different specimens of bone. It
is obvious that the bone ashes had been exposed to so strong a
heat as to drive off the carbonic acid from the carbonate of lime.
Now 10 lime requires 7 '8 5 carbonic acid to convert it into car-
bonate. Hence the carbonate of lime must have amounted to
17-85 per cent. From this it appears that the proportion of
phosphate of lime to carbonate of lime in human bones approaches
pretty nearly to that in sheep bones.
The following table exhibits the results of several analyses of
bones made by me :
1. Human thigh bone.
Cartilage, . 39-12 . 35-93
Phosphate of lime, 43-67 . 51-12
Carbonate of lime, 14-00 . 9-77
Magnesia, . 0-49 . 0-63
Soda, . 2-00 . 0-59
Potash, . 0-06 . trace
99-34 98-04
2. Ileum of a sheep.
Cartilage, . 43-30 . 47-20
Phosphate of lime, 50-58 . 46-35
Carbonate of lime, 4-49 . 4-88
Magnesia, . 0-86 . 0-64
Soda, . 0-31 . 2-09
Potash, . 0-19 0-25
99-73 101-41
* Gehlen's Jour. (2d series,) iii. 1 ; or Afhandlingar, i, 216.
Q
SOLID PARTS OF ANIMALS,
3. Ileum of ox.
Cartilage, . 48-5
Phosphate of lime, 45-2
Carbonate, of lime, 6*1
Magnesia, . 0-24
Soda, . . 0-20
Potash, . . 0-11
100-35
4. Tibia of a sheep.
Cartilage, . 51-97
Phosphate of lime, 40-42
Carbonate of lime, 7-03
Magnesia, . 0-22
Soda,
Potash,
5. Vertebrae of haddock.
Cartilage,
Phosphate of lime,
Carbonate of lime,
Magnesia,
Soda,
trace
99-83
39-49
56-08
3-57
0.79
0-79
100-72
6. Snout of saw-fish deprived of teeth.
Cartilage, &c.
Phosphate of lime,
Carbonate of lime,
Magnesia,
Soda,
Water,
98-66
The middle or compact part of the long bones contains but
little fatty matter ; but the extremities of these bones are cellu-
lar or spongy, and contain a great deal. The same remark ap-
plies to the extremities of the flat bones. M. D'Arcet, who has
TEETH. 243
paid great attention to the subject, informs us that these spongy
portions of bones are composed of,
Earthy salts, . 60
Cartilage, . 30
Fatty matter, . 10
100-*
The blood-vessels and several membranes of the body some-
times ossify. In such cases it would appear from the analysis of
an ossified pericardium by Petroz and Robinet, that, instead of
cartilage, such ossifications have an albuminous membrane much
smaller in quantity than the cartilage of real bones. The result
of their analysis was as follows :
Animal membrane, gelatin, and albumen, 24-2
Common salt and sulphate of soda, . 4O
Carbonate of lime, . . 6*5
Phosphate of lime, . . . 65*3
lOO'-Of
CHAPTER II.
OF TEETH.
THOUGH the teeth are in fact bones, yet, as they contain some
substances which do not occur in any other part of the bony
structure, they deserve to be described in a separate chapter.
The human teeth in an adult individual amount to 32 ;
16 being set in each jaw. There are 4 incisors or cutting teeth
in each jaw, placed in the fore-part of the mouth, forming the
convex prominent part of the dental arch. They are wedge-
shaped ; being intended, as the name implies, for cutting the food,
that only the quantity capable of being masticated may be taken
into the mouth at once.
There are two canine teeth in each jaw, one on each side of the
incisors. They have a single root like the cutting teeth, but
longer, and their crown terminates in a blunt point.
The bicuspid teeth or smaller molars are four in number in
*~Journ. de Pliarmacie, xv. 23C. f Ibid. ix. 507.
244 SOLID PARTS OF ANIMALS.
each jaw ; two next each incisor. Their roots, as the name im-
plies, terminate near their extremities in two points, and there
is a groove from the neck of the tooth to its bicuspid termina-
tion. The cutting extremities of the crown present two tuber-
cles, one external, the other internal.
The grinding teeth or larger molars are six in number in each
jaw, and are farthest back of all the teeth. These teeth in the
upper jaw have usually three roots, and in the under jaw two.
The upper surface of the crown is flat, but has four tubercles ar-
ranged crosswise, in order to triturate the food.
Every tooth is divided by anatomists into the root, the neck, and
the crown. The root, or the part of the tooth contained within
the alveolus, is similar in its nature to common bone ; the neck is
the part of the tooth intermediate between the root and crown, or
the portion just in contact with the gums. The crown is the
part of the tooth projecting into the mouth, and fully in view.
The central portion of it is bone, but exteriorly it is encased by
a layer of white and very hard laminated substance, called enamel.
This layer is thick on the upper and lateral parts of the crown,
but becomes thinner as it approaches the neck, and disappears
altogether in the root.
The teeth of the inferior animals differ in their form and struc-
ture from those of man. But a description of them belongs to the
comparative anatomist. They are composed of bone and enamel.
The tusks of the elephant have received the name of ivory.
In consequence of its hardness and compact texture, it is suscep-
tible of a fine polish, and is on that account applied to a great va-
riety of purposes. It is liable, especially East Indian ivory, to
become yellow. The tusks of some other animals, as the hip-
popotamus and walrus, consist also of ivory. Even human teeth
contained a portion of ivory. The enamel differs from ivory in
containing very little cartilage, while about a third part of the
weight of ivory consists of cartilaginous matter.
A tooth consists essentially of four parts.
1. The pulp within the cavity of the tooth. It is from it that
the whole tooth originates. In process of time this pulp is fre-
quently converted into bone by the deposition of calcareous salts.
2. The ivory. This constitutes almost the whole of the tooth.
It resembles bone in its composition ; but differs from common
bone in being harder and denser.
TEETH. 245
3. The enamel. It covers the crown of the tooth as far as
the neck. It is very hard, and is obviously intended to prevent
the tooth from wearing so fast as it otherwise would do while
performing the office of mastication. The enamel has no carti-
lage, and, consequently, has a higher specific gravity than the
ivory of the tooth.
4. The capsule. This is a thin double membrane which, be-
fore extrusion, covered the whole tooth. It is gradually worn
away on the crown ; though Mr Nasmyth has frequently found
it either entire, or fragments of it on the crown even of an
adult tooth.* It remains during life on the roots of the teeth.
But it is frequently ossified, and then gets the name of crusta
petrosa.
Leuwenhoek first observed in 1678 that the body of the tooth
is composed of a congeries of transparent tubes, so small, that six
or seven hundred of them together do not exceed the size of a hu-
man hair.f Purkinje, in his work on the teeth, published in 1835,
confirmed this observation of Leuwenhoek. If the calcareous
salts be removed by steeping a tooth in dilute muriatic acid, and
the cartilage be examined under a sufficiently powerful micro-
scope, it is found, he says, to consist of transparent tubes, running
from the centre to the circumference. They are not straight,
but curved, and their diameter does not exceed y-g-o th of an Eng-
lish line. They become smaller as they reach the outer surface
of the tooth, and seem to terminate in cells. They send out nu-
merous branches, especially towards their external extremity.
These tubes, according to Muller, in the tooth, not acted on by
muriatic acid, are white and opaque, being filled with the calca-
reous salts of bone ; not in crystals, but in very fine powder
usually cohering together. The ivory, it would appear from
Retzius's observations, is deposited layer by layer round the sur-
face of the pulp ; the most external layer having been first de-
posited.
The enamel adheres internally to a thin membrane, which
long resists water. It consists of hexagonal tubes which proceed
from the membrane. J
* On the structure, physiology, and pathology of the tooth. Medico- Chirurgi-
cal Transactions, Vol. xxii.
f Phil. Trans, xii. 1002.
| On the structure of the teeth, the reader is referred to an elaborate paper
by Retzius, published in the Memoirs of the Stockholm Academy for 1836, and
246
SOLID PARTS OF ANIMALS.
The following table exhibits the specific gravity of the enamel
of various teeth as determined by my trials :
Human temporary tooth, 2-711
Human adult tooth, 2-688
Hippopotamus, . 2'750
Elephant, . 2-843
Mean, :*>; . 2-748
The specific gravity of the ivory of various teeth is as follows :
Human temporary tooth, 2-090
Human adult tooth,
Cryptenopus Capensis,
Hippopotamus,
Walrus,
Mean, 1-994
The specific gravity of the decayed part of a human tooth was
1-533. That of the crusta petrosa of an elephant's tooth was
1-892.
The following table exhibits the constituents which I extracted
from the enamel of various teeth :
Animal membrane,
Subsesquiphosphate of]
Carbonate of lime,
Magnesia,
Chloride of potassium,
Chloride of sodium,
Water, . . 0-98
Sand, . 0-65
Elephant
Human
Human
Hippopotamus, molar
adult
temporary
tooth.
tooth.
tooth.
1-307 6-80
19-07
7-84
lime, 78-30 81-55
64-84
76-73
12-09 7-65
2-63
7-67
3-92 1-65
1-09
4-09
2-57 105
f 1-49
1-13
M-13
1-74
1-005
99-817 99-705
0-14
99-39
0-63
99-83
entitled Mikroskopiska under sokningar ofver T'dndernes, s'drdeles Taribenets
struktur. It contains a very complete history of all that has been done on the
subject, together with numerous interesting observations of his own.
When Mr Nasmyth's Researches on the development, structure, and diseases
of the teeth, at present in the press, make their appearance, we may expect a
great deal of new information j as he has been long and assiduously occupied
with the anatomy of these organs. His historical introduction already published
is very complete, and very interesting and instructive.
* It is obvious from the result of the analysis, that this enamel was not pure,
4
TEETH.
What is marked sand was in the hippopotamus enamel grains of
sand lodged mechanically. In human teeth it was silica, tinged
slightly with iron.
The following table exhibits the constituents which I ex-
tracted from the ivory of various specimens of teeth subjected to
analysis :
Human
Hippotaraus. Walrus. adult tooth.
Cartilage, , . 28-87 .32-11 25-38
Subsesquiphosphate of lime, 48-30 51-93 54-14
Carbonate of lime, . 7-90 2-58 5-76
Magnesia, . . 1-03 0-94 1-37
Chloride of potassium, . 0-30 ... \
Chloride of sodium, . . . . . 3-30 J
Silica, . . ... 0-21 0-33
Moisture, . 13-09 10-33 10-37
99-49 101-40 100-37
A carious human tooth, having a specific gravity of 1-533,
being subjected to analysis, yielded,
Cartilage, . 57-78
Subsesquiphosphate of lime, 30-00
Carbonate of lime, . 2-09
Magnesia with trace of silica
and peroxide of iron, 2*05
Chloride of potassium, 1-25
Moisture, . 9-45
102-62
The crusta petrosa from an elephant's tooth, having a specific
gravity of 1-892, being analyzed, yielded the following constitu-
ents :
but contained a good deal of ivory. The animal membrane was at least partly
cartilage. The deficiency was occasioned by a portion of the cartilage having
been dissolved in the muriatic acid. The specimen examined was in powder.
It was impossible to determine whether it was pure enamel by the eye.
SOLID PARTS OF ANIMALS.
Cartilage, . 31-05
Subsesquiphosphate of lime, 46-34
Carbonate of lime, . 6-32
Magnesia, . 2-81
Common salt, . 4-21
Water, . 10-86
101-59
It therefore resembles ivory in its composition as it does in its
specific gravity. The excess observable in some of the preced-
ing analyses may have been partly owing to the chlorides of po-
tassium and sodium not existing as such in the teeth but only
their bases. The analysis threw no light upon this. And I was
unable to extract either an alkali or a chloride from the teeth by
simply boiling them in water.
Berzelius analyzed the enamel and ivory of different teeth.*
The result was as follows :
Human. Ox.
Subsesquiphosphate of lime, 88*5 85-0
Carbonate of lime, . . 8-0 7*1
Phosphate of magnesia, 1-5 3-0
Soda, . . ... 1.4
Brown membranes, alkali water, 2-0 3*5
100-0 100-0
His analysis of the ivory of teeth gave the following result :
Human. Ox,
Cartilage and yessels, . 28-0 21-000
Subsesquiphosphate of lime, 64-3 63-15
Carbonate of lime, . 5-3 1-38
Phosphate of magnesia, . 1-0 2-07
Soda with some common salt, 1*4 2-40
100-0 100-00
Lassaignef published the result of his analysis of the teeth of
various animals a good many years ago. He did not separate
the enamel from the ivory ; but appears to have subjected the
•
* Traite de Chimie, vii. 479 ; or Afhandlingar, i. 222.
•f Jour, de Pharmacie, vii. 1.
TEETH. 249
whole tooth to analysis at once. The following table shows his
results.
Animal Phosphate Carbonate
matter. of lime. of lime.
Tooth of a child aged 1 day, 35 . 51 . 14-
Of a child aged 6 years, 28'57 . 60-01 . 11-42
Of an adult man, .29 .61 .10
Of a man aged 80 years, 33 . 66 1
Of an Egyptian mummy, 29 . 55-5 . 15*5
Front teeth of a rabbit, 31-2 . 59-5 . 9-3
Molar of a rabbit, 28-4 . 63-7 . 7-8
Molar of a rat, . 30-6 . 65-1 . 5-3
Molar of a boar, . 29'4 . 63 . 6-8
Tusk of a boar, . 26-8 . 69 . 4-2
Tusk of hippopotamus, 25-1 . 72 . 2-9
Front tooth of a horse, 31-8 . 58-3 . 10
Molar of a horse, 29-1 . 62 . 8-9
Front tooth of an ox, 28 . 64 8
Teeth of an orycteropus, 27-3 . 65-9 . 6-8
Teeth of a gavial, 30-3 . 61-6 8-1
Teeth of a viper, . 30 . 76-3 . 3-2
Poisonous tusks of viper, 21 . 73-8 . 5
Teeth of a carp, . 28 . 49- 16
Mr Pepys* made some analyses of teeth many years ago, which
it will be worth while to state.
From the enamel of the human tooth he obtained,
Phosphate of lime 78
Carbonate of lime, 6
Loss and water, 16
100
From the ivory of the teeth he got,
Roots of Teeth of Milk
the teeth. adults. teeth.
Phosphate of lime, 58 64 62
Carbonate of lime, 466
Cartilage, 28 20 20
Loss, . 10 10 12
100 100 100
* Fox on the Teeth, p. 96.
2,50 SOLID PARTS OF ANIMALS.
Mr Hatchett examined fossil bones from the rock of Gibraltar.
He found them to consist of phosphate of lime without any car-
tilage or soft animal part. Their interstices were filled with car-
bonate of lime. Hence they resemble exactly bones that have
been burnt. They must, then, have been acted upon by some
foreign agent ; for putrefaction, or lying in the earth, does not
soon destroy the cartilaginous part of bones. On putting a hu-
man os humeri, brought from Hythe in Kent, and said to have
been taken from a Saxon tomb, into muriatic acid, he found the
cartilaginous residuum nearly as complete as in a recent bone.
From the experiments of Morichini,* Klaproth,f and Fourcroy,
and Vauquelin,! we learn that fossil ivory and teeth of animals
frequently contain a portion of fluate of lime. Morichini and
Gay-Lussac endeavoured to prove that this salt existed even in
recent ivory, and that the enamel of the teeth was almost entirely
composed of it§ But the experiments of Wollaston, Brande, ||
Fourcroy, and VauquelinlF have shown that there does not exist
any sensible portion of fluoric acid in these substances while re-
cent. Berzelius, however, has announced that he separated 3 per
cent, of fluate of lime from fresh teeth, and that he has detect-
ed it also in bones nearly in the same proportion. He even
affirms that it exists in urine.**
When the cartilage of teeth is boiled in water it dissolves
with the exception of a minute quantity of fibrous matter, which
may be the blood-vessels. The solution possesses the characters
of collin, not of chondrin.
CHAPTER III.
OF CARTILAGE.
THE name cartilage is applied to a hard, highly elastic, white
substance, often with a pearly lustre, which is attached to or
constitutes a part of the texture of bones. The cartilages in the
» Phil. Mag. xxiii. 265. f Gehlen's Jour. iii. 625.
| Phil. Mag. xxv. 265. § Ibid, xxiii. 265.
|| Nicholson's Journ. xiii. 216. f Phil. Mag. xxv. 266.
** Gehlen's Journ. vi 591.
CARTILAGE. 251
human body may be subdivided into three different sets. 1.
Those which at one period of life existed instead of the bones,
and which, after the bones are formed, constitute an essential
part of the bony texture. These have been already treated of
in the last two chapters. 2. Those cartilages which cover the
extremities of those bones which constitute moveable articula-
tions, and which are called cartilages of incrustation. These
cartilages are covered with a syuovial membrane which adds to
the polish of their faces. The greater and the more moveable
the articulations are to which these cartilages belong, the thicker
they are. In old age, these cartilages are occasionally converted
into bones. A portion of cartilage tipping the ileum bone of
an ox had a specific gravity of 1 '1521. 3. The cartilages which
unite the ribs to the sternum or to one another, those of the la-
rynx and of the nose, constitute the third set. They are cover-
ed by a fibrous membrane called perichondrium. They also (if
we except those of the nose) frequently ossify in old age;
The facts respecting the structure of cartilages, so far as in-
vestigated, have been stated in the preceding chapters. They
seem, if we can confide in the microscopic observations of Pur-
kinje, Retzius, and Miiller, to consist of a congeries of very minute
tubes. When these tubes are filled with calcareous salts the
cartilages are converted into bone. It is evident from the dis-
eases to which cartilages are liable that they are supplied with
vessels. But in ordinary cases these vessels do not seem to con-
vey red blood ; though when inflammation intervenes they may
be occasionally seen filled with red blood. And such inflam-
mations may run the same career as in other organs.
In the year 1827, Fromherz and Gugert* analyzed the carti-
lage of the ribs of a young man, aged 20 years, and found it, after
having been dried as completely as possible in the temperature
(of 212°, composed of,
Animal matter, . 96-598
Salts, . 3-402
100-000
The salts being subjected to an analysis were found composed
of,
* Schweiger's Jour. 1. 188.
SOLID PARTS OF ANIMALS.
Carbonate of soda, . 35-068
Sulphate of soda, . 24-241
Common salt, . '8-231
Phosphate of soda, . 0-925
Sulphate of potash, 1 -200
Carbonate of lime, 18-372
Phosphate of lime, 4*056
Phosphate of magnesia, 6-908
Peroxide of iron and loss, 0'999
100-000
The animal portion was soluble by long boiling in water, and
was converted into gelatin. It has been already stated in a for-
mer chapter of this volume, that Miiller has shown that gelatin,
from the permanent cartilages, differs in its properties from collin,
or the gelatin from the skin and serous membranes ; being pre-
cipitated from its solution in water by alum, sulphate of alumina,
acetate of lead, and persulphate of iron, which have no action on
the aqueous solution of collin. On that account he has distin-
guished it by the name of chondrin. The properties of chondrin,
so far as they have been investigated, have been given in a pre-
ceding chapter of this volume.
The cartilages of the ribs, those that unite them to the ster-
num and to each other, give chondrin. Miiller found that the
cartilages obtained from bones by removing the bone earth, by
means of an acid, yielded collin ; yet the same cartilages before
ossification has taken place yield chondrin. From this it seems
to follow that a change takes place in the nature of the cartilage
during the process of ossification.
It is probable that the cartilages of cartilaginous fish would
yield chondrin, though I do not know that the experiment has
been tried.
The cartilages which cover the extremities of bones destined
to move on each other, cannot be converted into collin or chon-
drin by boiling in water. When deprived of the membrane that
covers them, they are much brittler than the cartilages of the
ribs. So far as I know, no chemical analysis of such cartilages
has been hitherto attempted. Mr Hatchett conceives them to
have the properties of coagulated albumen. But this conjecture
would require to be verified by actual experiment before it could
be admitted as true.
MARROW. 253
It is well known that many fish instead of bones have carti-
lages. The cartilaginous dorsal vertebra of the Squalus cornubi-
ensis was analyzed by Marchand,* who obtained from it
Animal combustible matter, . 5 7 '07
Phosphate of lime, . 32-46
Sulphate of lime, . 1-87
Carbonate of lime, . 2 '5 7
Fluoride of calcium, trace . —
Sulphate of soda, . 0-80
Chloride of sodium, . 3*00
Phosphate of magnesia, . 1 -03
Silica, alumina, and loss, . 1-20
100-00
The flat cartilages of the skate gave him,
Animal combustible matter, . 78*46
Carbonate of lime, . 2-61
Phosphate of lime, . 14-20
Sulphate of lime, . 0-83
Fluoride of calcium, trace
Chloride of sodium, , 2-46
Sulphate of soda, . 0-70
Phosphate of magnesia and loss, 0-74
100-00
The translucent cartilages consisted almost entirely of animal
matter, as had been previously shown by Chevreul.
CHAPTER IV.
OF MARROW.
THE hollows of the long bones are, in living animals, filled with
a peculiar species of fat matter, to which the name of marrow has
been given. In some bones this matter is a good deal mixed
with blood, and has a red colour ; in others, as the thigh bones,
* Poggendorfs Annalen, xxxviii. 354.
SOLID PARTS OF ANIMALS.
it is purer, and has a yellow colour. Various experiments on
this matter were made by the older chemists, showing it to be
analogous to animal fats,* and pointing out some of its peculia-
rities. Berzelius has examined it in detail, and published the re-
sults of his experiments.! The marrow on which his trials were
made was obtained from the thigh-bone of an ox.
1. When marrow is digested in cold water it becomes lighter
coloured, while the water acquires the colour which it would have
received had it been digested on blood. When this water is
boiled it becomes muddy, and a dark-brown matter precipitates.
This matter consists of coagulated albumen mixed with some
phosphate of lime, and phosphate of iron. A small portion of a
yellow-coloured salt is dissolved by the action of alcohol or wa-
ter. This matter, separated from marrow by water, is obviously
owing to the blood with which it was mixed. The quantity which
Berzelius obtained from marrow amounted to iJ5th part of the
whole. The portion of it dissolved by water and alcohol con-
sisted partly of gelatin and common salt, and partly of the pe-
culiar brown extractive matter obtained by Thouvenel from the
muscles of animals, which will be described in a subsequent chap-
ter, when treating of the muscles. The proportion of these sub-
stances obtained by Berzelius from marrow amounted to about
j£0th part of the whole.
2. When marrow is boiled in water, the greatest part of it
melts and swims upon the surface of the liquid. The water is at
first muddy and milky, but becomes transparent on standing.
When passed through the filter, a substance is separated which
becomes greyish-green, and semitransparent when dry. More
of this matter precipitates when the liquid is evaporated. When
the water is evaporated to dryness, a substance is obtained of a
sharp aromatic taste like the marrow of roasted meat. These
two substances consist chiefly of extractive, gelatin, and a pecu-
liar substance, which approaches the nature of albumen in its
properties.
3. When marrow, thus purified, is melted in water and passed
through a cloth, a quantity of blood-vessels and skins remain up-
on the cloth, amounting to about t J^th part of the whole.
4. Marrow, thus freed from its impurities, has a white colour
with a shade of blue ; its taste is insipid and rather sweetish. It
* Neumann's Chemistry, p. 560. f Gehlen's Jour. 2d series, ii. 287.
MARROW. 255
softens by the heat of the hand, and melts when heated to 113°.
When cooled slowly, it crystallizes in sphericles like olive oil.
It burns with a flame like tallow. When distilled, it gives first
a transparent fluid yellowish oil, accompanied by carbonic acid
gas, water, and heavy inflammable air. Afterwards there comes
over a white solid oil, accompanied by a less copious evolution of
gaseous bodies, and which does not become dark-coloured, as
happens when tallow is distilled. This had already been observ-
ed by Neumann. This solid oil has a disagreeable smell, amounts
to 0-3 of the marrow distilled, reddens vegetable blues, and when
boiled in water, gives out a portion of sebacic acid, which Berze-
lius considered as benzoic acid.
The empyreumatic oil combines readily with alkalies and their
carbonates. With the latter it forms a snow-white soap, insolu-
ble in water, though it increases in bulk when placed in contact
with that liquid. It combines also with the earths, and forms
soaps likewise insoluble in water.
The water which comes over during the distillation of marrow
is colourless, has a fetid and sour smell, and an empyreumatic
taste. It contains a little acetic acid, empyreumatic oil, and pro-
bably sebacic acid ; but exhibits no traces of ammonia.
The gaseous products amount to -^th of the marrow distilled.
They contain no sulphur nor phosphorus, and consjst of carbo-
nic acid and heavy inflammable air, which burns with a white
flame, and seems to contain oil in solution.
The charry matter in the retort amounts to 0-05 of the mar-
row distilled. It is dark-brown, heavy, and brilliant It is inci-
nerated with difficulty, and leaves an ash consisting of phosphate
of lime, carbonate of lime, and some soda.
5. Concentrated sulphuric acid dissolves marrow without the
assistance of heat. The solution has the appearance of a brown
syrup ; and when the acid is diluted with water, the marrow se-
parates unaltered. When heat is applied, the acid decomposes
the marrow and forms a resinous coal.
Diluted nitric acid digested on marrow, in a moderate heat,
renders it yellow, and gives it more consistence, and the smell of
old bones. Concentrated nitric acid dissolves marrow without
the assistance of heat, and the marrow is not precipitated by the
addition of water.
6. Marrow combines with alkalies and forms soap. Boiling
SOLID PARTS OF ANIMALS.
alcohol and ether dissolve a small portion of it, which precipitates
again as the solution cools.
Marrow from the thigh-bone of an ox was found by Berzelius
to be composed of the following substances :
Pure marrow, . O96
Skins and blood-vessels, . 0-01
Albumen,
Gelatin,
Extractive,
Peculiar matter,
Water,
0-03
1-00
From the preceding detail it appears, that pure marrow is a
species of fixed oil, possessing peculiar properties, and approach-
ing somewhat to butter in its nature. But it differs considerably
in its appearance in different parts of the body, owing chiefly, in
all probability, to a greater or smaller mixture of blood.
CHAPTER V.
OF SHELLS.
UNDER the name of shells I include all the bony coverings of
the different species of shell-fish. For almost all the knowledge
of these substances that we possess, we are indebted to the im-
portant dissertations of Mr Hatchett. A few detached facts, in-
deed, had been observed by other chemists ; but his experiments
gave us a systematic view of the constituents of the whole class.
Shells, like bones, consist of calcareous salts united to a soft
animal matter ; but in them the lime is united chiefly to carbo-
nic acid, whereas in bones it is united to phosphoric acid. In
shells the predominating ingredient is carbonate of lime, where-
as in bones it is phosphate of lime. This constitutes the charac-
teristic difference in their composition.
Mr Hatchett has divided shells into two classes. The first are
usually of a compact texture, resemble porcelain, and have an
enamelled surface, often finely variegated. The shells belong-
ing to this class have been distinguished by the name ofporceta-
SHELLS. £57
neons shells. To this class belong the various species of valuta,
cyprcea, &c. The shells belonging to the second class are usu-
ally covered with a strong epidermis, below which lies the shell
in layers, and composed entirely of the substance well known by
the name of mother-of-pearl* They have been distinguished by
the name of mother-of-pearl shells. The shell of the fresh water
muscle, the Haliotis iris, the Turbo olearius, are examples of such
shells. The shells of the first of these classes contain a very
small portion of soft animal matter ; those of the second contain
a very large proportion. Hence we see that they are extremely
different in their composition.
1. Porcelaneous shells, when exposed to a red heat, crackle
and lose the colour of their enamelled surface. They emit no
smoke or smell ; their figure continues unaltered, their colour
becomes opaque white, tinged partially with pale-gray. They
dissolve when fresh with effervescence in acids, and without leav-
ing any residue ; but if they have been burnt, there remains al-
ways a little charcoal. The solution is transparent, gives no
precipitate with ammonia or acetate of lead ; of course, it con-
tains no sensible portion of phosphate or sulphate of lime. Car-
bonate of ammonia throws down an abundant precipitate of car-
bonate of lime. Porcelaneous shells, then, consist of carbonate
of lime cemented together by a small portion of an animal
matter, which is soluble in acids, and therefore resembles ge-
latin.f
Patellae from Madeira, examined by Mr Hatchett, were found,
like the porcelaneous shells, to consist of carbonate of lime ; but
when exposed to a red heat, they emitted a smell like horn ; and
when dissolved in acids, a semiliquid gelatinous matter was left
behind. They contain, therefore, less carbonate of lime and
more gelatin, which is of a more viscid nature than that of por-
celaneous shells.
2. Mother-of-pearl shells, when exposed to a red heat, crackle,
blacken, and emit a strong fetid odour. They exfoliate, and be-
come partly dark-grey, partly a fine white. When immersed in
acids, they effervesce at first strongly ; but gradually more and
more feebly, till at last the emission of air-bubbles is scarcely
perceptible. The acids take up only lime, and leave a number
* Herissant, Mem. Par. 1766, p. 22. Hatchett, Phil. Trans. 1799, p. 317.
f Hatchett, Phil. Trans. 1799, p. 317.
R
SOLID PARTS OF ANIMALS.
of tliin membranous substances, which still retain the form of the
shell. From Mr Hatchett's experiments, we learn that these
membranes have the properties of coagulated albumen. Mother-
of-pearl shells, then, are composed of alternate layers of coagu-
lated albumen and carbonate of lime, beginning with the epider-
mis, and ending with the last-formed membrane. The animals
which inhabit these shells increase their habitation by the addi-
tion of a stratum of carbonate of lime, secured by a new mem-
brane ; and as every additional stratum exceeds in extent that
which was previously formed, the shell becomes stronger as it
becomes larger.*
Oyster shells, according to the analysis of Bucholz and
Brandes, are composed of
Albuminous matter, . 0-5
Lime, . . 54-1
Carbonic acid, . .44*5
Phosphate of lime, . 1 '2
Alumina, . . 0-2.
100-5 f
The scales on the outside of oyster shells, according to the
analysis of John, are composed of
Animal matter soluble in water with ~i
common salt and trace of phosphates, )
Ditto insoluble in water, . . 10
Carbonate of lime, . . .87
loot
Though this in general is the structure of the mother-of-pearl
shells, yet there is a considerable difference between the propor-
tion of the component parts and the consistency of the albumi-
nous part. Some of them, as the common oyster- shell, approach
nearly to the patellae, the albuminous portion being small, and
its consistence nearly gelatinous ; while in others, as the Haliotis
iris, the Turbo olearius, the real mother-of-pearl, and a species of
fresh-water muscle analyzed by Hatchett, the membranes are
distinct, thin, compact, and semitransparent§ Mother-of-pearl
contains
• Hatchett, Phil. Trans. 1799, p. 317. t Gmelin's Handbuch, ii. 1477.
\ Chem. Schr. vi. 103. § Hatchett, Phil. Trans. 1799, p, 317.
SHELLS. £59
Carbonate of lime, 66
Membrane, . 24
90*
Pearl, a well-known globular concretion, which is formed in
some of these shells, resembles them exactly in its structure and
composition. It is a beautiful substance of a bluish-white colour,
iridescent, and brilliant. It is composed of concentric and alter-
nate coats of thin membrane and carbonate of lime. The iri-
descence is obviously the consequence of the lamellated struc-
ture.!
It is said that the inhabitants of Ceylon have discovered a very
remarkable way of bleaching pearls that have become yellow.
They mix them with the seeds mingled with earth, with which
they feed their fowls ; the birds swallow the pearls ; the stomach
is opened in one or two minutes after, and the pearls are found
perfectly bleached. Were they left too long in the stomach,
they would doubtless be dissolved.^ If this statement be true,
might not the pearls be bleached by steeping them in a very di-
lute muriatic acid for a minute or two.
Mr Hatchett found that what is called the bone of the cuttle
fish is exactly similar to mother-of-pearl shells in its composition.
From the comparative analysis of shells and bones, Mr Hat-
chett was induced to compare them together, and has shown that
porcelaneous shells bear a striking resemblance to enamel of
teeth ; while mother-of-pearl shells bear the same resemblance
to the substance of teeth or bone ; with this difference, that in
enamel and bone the earthy salt is phosphate of lime, whereas in
shells it is pure carbonate of lime.
* Merat-Guillot, Ann. de Chim. xxiv. 71.
t Hatchett, Phil. Trans. 1799. \ Jour de Pharmacie, xi. 175.
260 SOLID PARTS OF ANIMALS.
CHAPTER VI.
OF CRUSTS.
By crusts we understand those bony coverings of which the
whole external surface of crabs, lobsters, and other similar sea
animals are composed. Mr Hatchett found them composed of
three ingredients: 1. A cartilaginous substance, possessing the
properties of coagulated albumen ; 2. Carbonate of lime ;
3. Phosphate of lime. By the presence of this last substance
they are essentially distinguished from shells, and by the great
excess of carbonate of lime above the phosphate they are equally
distinguished from bones. Thus the crusts lie intermediate be-
tween bones and shells, partaking of the properties and consti-
tution of each. The shells of the eggs of fowls must be referred
likewise to the class of crusts, since they contain both phosphate
and carbonate of lime. The animal cement in them, however,
is much smaller in quantity. From the experiments of Berniard
and Hatchett, it is extremely probable that the shells of snails
are composed likewise of the same ingredients, phosphate of lime
having been detected in them by these chemists.
Mr Hatchett examined the crusts of crabs, lobsters, prawns,
and cray fish. When immersed in diluted nitric acid these
crusts effervesced a little, and gradually assumed the form of a
yellowish-white soft elastic cartilage, retaining the form of the
crust. The solution yielded a precipitate to acetate of lead, and
ammonia threw down phosphate of lime. Carbonate of ammonia
threw down a much more copious precipitate of carbonate of lime.
On examining the crust which covers different species of echini,
Mr Hatchett found it to correspond with the other crusts in its
composition. Some species of star- fish yielded phosphate of
lime, others none ; hence the covering of that genus of animals
seems to be intermediate between shell and crust
With these observations of Mr Hatchett the analysis of Me-
rat-Guillot corresponds. From lobster crust he obtained,
Carbonate of lime, . \ 60
Phosphate of lime, . 14
Cartilage, . . 26
100*
* Ann. de Chim. xxxiv. 71.
CRUSTS. 261
One hundred parts of cray fish crust contain
Carbonate of lime, . 60
Phosphate of lime, . .12
Cartilage, . . 28
100*
John analyzed the shield or shell of the fresh water crab in
181 If and extracted from it the following constituents,
Cartilage, . . .33-3
Carbonate of lime, including a little common salt, )
iron, manganese, and colouring matter, j
Phosphate of lime, . . . 5 *7
100-0
Lobster's claws were subjected to analysis by M. Pagurus in
1823. He obtained
Animal matter, . 17*18
Carbonate of lime, . 68-36
Phosphate of lime, . 14-06
99-60J
The shell of the lobster gave him
Animal matter, . . 28-6
Soda salts, . . 1-6
Carbonate of lime, . 62-8
Phosphate of lime, . 6-0
Phosphate of magnesia . 1-0
100-0
One hundred parts of hen's egg-shells contain
Carbonate of lime, . 89-6
Phosphate of lime, . 57
Animal matter, . 4 '7
100.0§
* Merat-Guillot, Ann. de China, xxxiv. 71.
f Chemische Untersuchungen, ii. 49.
J: Schweigger's Jour, xxxix. 440.
§ Vauquelin, Ann, de Chim. xxix. 6.
SOLID PARTS OF ANIMALS.
CHAPTER VII.
OF ZOOPHYTES.
MANY of the substances called zoophytes have the hardness
and appearance of shell or bone, and may therefore be included
among them without impropriety. Others, indeed, are soft, and
belong rather to the class of membrane or horn ; but of these
very few only have been examined. Indeed scarcely any '^chemi-
cal experiments have been published on these interesting subjects,
if we except the dissertation by Hatchett, in the Philosophical
Transactions for 1800, which has been so often quoted. From
this dissertation, and from a few experiments of Merat-Guillot,
we learn that the hard zoophytes are composed chiefly of three
ingredients : 1. An animal substance of the nature of coagulat-
ed albumen, varying in consistency ; sometimes being gelatinous
and almost liquid, at others of the consistency of cartilage. 2.
Carbonate of lime. 3. Phosphate of lime.
In some zoophytes the animal matter is very scanty, and phos-
phate of lime wanting altogether ; in others the animal matter is
abundant, and the earthy salt pure carbonate of lime ; while in
others the animal matter is abundant, and the hardening salt a
mixture of carbonate of lime and phosphate of lime ; and there
is a fourth class almost destitute of earthy salts altogether. Thus,
there are four classes of zoophytes ; the first resemble porcelane-
ous shells, the second resembles mother-of-pearl shells, the third
resembles crusts, and the fourth horn.
1. When the Madrepora virginea is immersed in diluted nitric
acid it effervesces strongly, and is soon dissolved. A few gela-
tinous particles float in the solution, which is otherwise transpa-
rent and colourless. Ammonia precipitates nothing ; but its
carbonate throws down abundance of carbonate of lime. It is
composed, then, of carbonate of lime and a little animal matter.
The following zoophytes yield nearly the same results :
Madrepora muricata.
labyrinthica.
Millepora cerulea.
alcicornis.
Tubipora musica,
2. When the Madrepora ramea is plunged into weak nitric
ZOOPHYTES. 263
acid, an effervescence is equally produced ; but after all the so-
luble part is taken up, there remains a membrane which retains
completely the original shape of the madrepore. The substance
taken up is pure lime. Hence this madrepore is composed of
carbonate of lime, and a membranaceous substance which, as in
mother-of-pearl shells, retains the figure of the madrepore. The
following zoophytes yield nearly the same results :
Madrepora fascicularis.
Millepora cellulosa.
fascialis.
truncata.
Iris hippuris.
The following substances, analyzed by Merat-Guillot, belong
to this class from their composition, though it is difficult to say
what are the species of zoophytes which were analyzed. By red
coral he probably meant the Gorgonia nobilis, though that sub-
stance is known, from Hatchett's analysis, to contain also some
phosphate.
Articulated
White Coral. Red Coral. Coralline.
Carbonate of lime, . 50 . 53-5 . 49
Animal matter, . 50 . 46-5 . 51
100 100-0 100*
3. When the Madrepora potymorpha is steeped in weak nitric
acid, its shape continues unchanged ; there remaining a tough
membranaceous substance of a white colour and opaque, filled
with a transparent jelly. "The acid solution yields a slight pre-
cipitate of phosphate of lime when treated with ammonia, and
carbonate of ammonia throws down a copious precipitate of car-
bonate of lime. It is composed, therefore, of animal substance,
partly in the state of jelly, partly in that of membrane, and har-
dened by carbonate of lime together with a little phosphate of
lime.
Flustra foliacea, treated in the same manner, left a finely re-
ticulated membrane, which possessed the properties of coagulated
albumen. The solution contained a little phosphate of lime, and
yielded abundance of carbonate of lime when treated with the
alkaline carbonates. The Corallina opuntia, treated in the same
* Merat-Guillot, Ann. de Chim. xxxiv. 71.
SOLID PARTS OF ANIMALS.
manner, yielded the same constituents ; with this difference, that
no phosphate of lime could he detected in the fresh coralline, hut
the solution of burnt coralline yielded traces of it. The Iris ochra-
cea exhibits the same phenomena, and is formed of the same con-
stituents. When dissolved in weak nitric acid, its colouring mat-
ter falls in the state of a fine red powder, neither soluble in ni-
tric nor muriatic acid, nor changed by them : whereas the ting-
ing matter of the Tubipora musica is destroyed by these acids. The
branches of this iris are divided by a series of knots. These
knots are cartilaginous bodies connected together by a membra-
nous coat. Within this coat there is a conical cavity filled with
the earthy or coralline matter ; so that, in the recent state, the
branches of the iris are capable of considerable motion, the knots
answering the purpose of joints.
When the Gorgonia nobilis, or red coral, is immersed in weak
nitric acid, its colouring matter is destroyed, an effervescence
takes place, and the calcareous part is dissolved. There remains
an external tubulated membrane of a yellow colour, inclosing a
transparent gelatinous substance. The solution yields only car-
bonate of lime : but when red coral is heated to redness, and
then dissolved, the solution yields a little phosphate of lime also.
Red coral is composed of two parts : an internal stem, composed
of gelatinous matter and carbonate of lime ; and an external
covering or cortex, consisting of membrane hardened by the cal-
careous salts, and both coloured by some unknown substance.
The Gorgonia ceratophyta likewise consists of a stem and cor-
tex. The stem is composed of cartilage, hardened chiefly by
phosphate of lime ; and containing little carbonate of lime ; but
the cortex consists of membrane, hardened almost entirely by
carbonate of lime. The Gorgonia flabellum is almost exactly si-
milar. The cortex of the Gorgonia suberosa yielded gelatine to
boiling water ; when steeped in acids, it left a soft yellowish mem-
brane, and the acid had taken up a little phosphate and a large
portion of carbonate of lime. The stem contained scarcely any
earthy salt. When burnt, it left a little phosphate of lime. To
water it yielded a little gelatin; but it consisted chiefly of a
horny substance, analogous to coagulated albumen. The Gorgo-
nia setosa and pectinata exhibited the same phenomena,
4. Gorgonia antiphates, like the other species of gorgonia, has
a horny stem, but it is destitute of a cortex. To boiling water
BRAIN AND NERVES. 265
it gives out some gelatin. When steeped in nitric acid it be-
comes soft, and exhibits concentric coats of thin opaque brown
membranes, of a ligneous aspect. It contains no earthy salt.
With potash it forms an animal soap, and possesses nearly the
properties of horn.
The stems of the Gorgonia umbraculum and verrucosa resemble
that of the Gorgonia antiphates ; but these are both provided
with a cortex composed of membrane and carbonate of lime.
The Antiphates ulex and myriophyla resemble almost exactly
the horny stem of the Gorgonia antiphates.
Mr Hatchett analyzed many species of sponges, but found
them all similar in their composition. The Spongia cancellata,
oculata, infundibuliformis, palmata, and officinalis, may be men-
tioned as specimens. They consist of gelatin, which they gra-
dually give out to water, and a thin brittle membranous sub-
stance, which possesses the properties of coagulated albumen.
Hence the effect of acids and alkalies on them.
The Alcyonium ficus, asbestinum, and arbor eum, resemble very
much the cortex of the Gorgonia suberosa in their composition.
They yield a little gelatin to water. In nitric acid they soften,
and appear membranous. The acid takes up the carbonate of
lime, and likewise a little phosphate, at least when the substance
has been previously heated to redness.
CHAPTER VIII.
OF BRAIN AND NERVES.
THE brain, that wonderful part of the human body upon
which the exercise of the different senses and of the understand-
ing depends, is situated within the cranium, and is usually di-
vided into the cerebrum and the cerebellum, or the brain, and the
little' brain. The cerebrum is situated farthest up, and is the
part of the brain which comes into view when the parietal and
frontal bones are removed. In an adult individual it is about
eight times the size of the cerebellum.
\ The brain is enveloped in three membranes, which have re-
ceived the names of the dura mater, pia mater, and arachnoid mem-
266
SOLID PARTS OF ANIMALS.
brane. The dura mater, which is most external of the three, is
thick, firm, and resisting, and consists, in fact, of the two coats ;
the outermost one being fibrous, and the innermost serous. It
lines the cranium or scull, to which it is attached, while, at the
same time, it invests the brain, and sends in processes which are
interposed between its different parts. The pia mater, which is
in contact with the brain, is a thin lamella of cellular tissue, per-
meated by numerous minute capillary arteries. It invests the
medulla spinalis as well as the brain, and dips into the sulci be-
tween the convolutions of the latter. The arachnoid membrane
is smooth and transparent. One part of it invests the spinal
cord and the brain, passing over its surface, without dipping into
the convolutions. The other lines the dura mater and its several
processes with which it is connected.
The brain occupies the principal part of the cranial cavity.
Its superior surface is convex and arched ; and is divided into
two equal and similar hemispheres by the duplication 'of the
dura mater called the/«£r. The surface of the brain is render-
ed unequal by several depressions and elevations marked upon
it The elevations are called convolutions, and are situated be-
tween the depressions. The brain itself consists of two substances ;
the outermost portion has a gray colour, and is called the corti-
cal part, while the innermost portion, which is white, is called the
medullary part. The cortical part forms a layer of variable
thickness on the surface of the cerebrum and cerebellum. It is
found also within the brain ; sometimes it is covered by the me-
dullary portion ; sometimes it seems intimately mixed with it ;
or the two substances are disposed in alternate layers.
The first person who attempted to ascertain the structure of
the brain by microscopic observations was Leuwenhoek. In the
year 1674, he announced that the medullary portion of the brain
of a cow was composed of very subtile globules.* Delia Torre
stated that the brain consisted of a pulpy matter swimming in a vis-
cid and transparent fluid. f According to the microscopical obser-
vations of Ehrenberg,t the cortical substance of the brain con-
sists of a fine net-work of vessels, in many places containing par-
ticles of blood. This net- work is connected with the vessels of
the pia mater. Besides this fine net-work, the cortical portion
* Phil. Trans, xi. 106. f Poggendorf s Annalen, xxviii. 449.
Ibid, xxviii. 451.
BRAIN AND NERVES. 267
of the brain consists of a very fine granular soft mass, in which
here and there larger grains are deposited in nests or layers.
The larger grains are free ; the very fine grains, whenever their
softness, sraallness, and transparency allow them to be seen, are
united together in rows by very delicate threads. The white or
medullary substance shows also many distinct fibres, continua-
tions of the cortical fibres, and passing in the same direction to-
wards the base of the brain. They are not simple cylindrical
threads ; but resemble strings of pearls, the pearls not being in
contact, but kept at a little distance from each other. They are
always straight, commonly parallel, sometimes crossing each
other ; in some rare cases they may be seen splitting into two,
but not anastomosing. Near the bases of the brain we find be-
tween knotty bundles of fibres much thicker fibres always isolat-
ed. These last show distinctly an inner and outer limit of their
walls, from which it is evident that they are hollow tubes. We
may call them varicose tubes or canals, because they swell out
in many places, resembling little blown bladders attached to each
other by a narrow tube.
The interior of these varicose tubes is quite transparent, so
that we might conceive them to be filled with vapour or with
water. The milk-white colour which they have when viewed by
the naked eye, is owing to the liquid contained in them, being of
a milk-white colour, and somewhat muddy. This matter even
when magnified 3000 times, does not exhibit any granular sub-
stance as the cause of this muddiness. The milk-white colour
is wanting in the cortical substance of the brain. It consists of
the points or beginnings of the varicose tubes, which exhibit
their walls or boundaries, but want the bulky contents which
exist in the medullary tubes. From this it is evident that the
white colour is owing entirely to the contents of the tubes.
When the tubes are torn, they contract ; but nothing can be per-
ceived coming out of them. The large brain tubes converge to-
wards-the place in the basis of the brain from which the nerves
proceed, and pass over their origins.
The nerves of the senses — seeing, hearing, and smelling, to-
gether with the great sympathetic, consist of cylindrical parallel
tubes about Ti5th of a line in diameter, running close to each
other, but not anastomosing. They are united in bundles,
which again form larger bundles, called nervous cords. Each
268 SOLID PARTS OF AMIMALS.
bundle with the whole cord is covered by a continuation of the pia
mater. Very often different nervous bundles unite by false
anastomoses, the tubes of one bundle passing into another, and
running along with it ; yet two tubes never unite together so as
to become one, as happens with the blood-vessels. In the great
sympathetic minute-jointed or varicose tubes may be distinctly
seen mixed with larger cylinders.
The first attempt to analyze the brain was made by M. Thou-
ret in 1790.* It was at that time that a vast number of dead
bodies which had been hurried in the Saintes Innocent burial-
ground in Paris were exhumed, and it was observed with some
surprise, that in many of these bodies the brain, after an interval
of a great many years, remained still unaltered, and free from
putrefaction. M. Thouret made some experiments on the brain,
in order to account for this long preservation, and concluded from
them that the brain is a soap, composed of an oily matter similar
(if not the very same) with spermaceti united to a fixed alkali.
In 1793 M. Fourcroy published a set of experiments on the
brains of calves, sheep, and man. * He showed that the brain,
besides the animal matter of which it chiefly consists, contains a
small quantity of the phosphates of lime, ammonia, and soda ;
but no free fixed alkali, as Thouret had stated. He subjected
the animal matter of brain to the action of heat, of water, of sul-
phuric acid, of dilute nitric acid, of muriatic acid, and of alcohol.
The last reagent when boiled with brain dissolved a portion of
it, which was deposited, as the alcohol cooled, in brilliant plates
of a yellowish-white colour. This was the substance which
Thouret considered as analogous to spermaceti ; but which Four-
croy showed had no analogy whatever to that substance. He
considered it as constituting a peculiar substance differing from
every other ; (though he did not distinguish it by any peculiar
name,) but approaching nearer to albumen than to anything else.
In 1812, Vauquelin published a set of experiments on the cere-
bral matter of man and some other animals.! He treated the
brain successively with boiling alcohol as long as that liquid con-
tinued to dissolve anything; it deposited, on cooling, a white
matter in plates, the same as had been previously observed by
* Jour, de Phys. xxxviii. 329. f Ann. de China, xvi. 282.
\ Annals of Philosophy, i. 332, or Ann. de Chim. Ixxxi. 37.
BRAIN AND NERVES. 269
Fourcroy. Another fatty matter remained in solution, and was
obtained by distilling off the greatest part of the alcohol, and
drying the residue by heat. Vauquelin concluded from his ex-
periments that the constituents of the brain were
Water, . 80-00
White fatty matter, 4-53
Reddish fatty matter, 070
Albumen, • 7-00
Osmazome, . 1*12
Phosphorus, . . 1*50
Acids, salts, and sulphur, 5-15
100-00
The salts were phosphates of potash, lime, and magnesia and a
little common salt.
In 1816 a number of experiments on the brain of calves and
oxen was published by John. * In 1830 Lassaigne gave a che-
mical analysis of the retina and the optic nerves, f The retina
has been generally considered by anatomists as a mere expansion
of the optic nerve, and this opinion has been confirmed by Las-
saigne, who found the constituents of each the same, excepting
that the retina contained much more water than the optic nerve.
The constituents of the retina were,
Water, .... 92-90
Saponifiable fat and cerebrin, . 0-85
Albumen, . . . . 6-25
100-00
While the optic nerve gave,
Water, .... 70-36
Cerebrin, . . . .4-40
Osmazome and common salt, . 0-42
Gelatin, .... 2.75
Albumen, . . . .22-07
100-00
In 1834, M. Couerbe published an interesting set of experi-
ments on the brain. :f He employed both alcohol and ether as
* Chemische Untersuchungen, iv, 160.
t Ann. de Chim. et de Phys. xlv. 215, $ Ibid. Ivi. 160.
SOLID PARTS OF ANIMALS.
solvents, and discovered, besides Vauquelin's white substance,
to which the name of cerebrate was given, four other constituents,
namely, cholesterin, cephalote, stearoconote, and eleancepholote.
An elaborate set of experiments on the analysis of the brain
was published by Fremy in 1841. * He confirmed the existence
of cerebrote and cholesterin, discovered by Vauquelin and Couer-
be. But showed that cerebrote, when pure, possesses acid pro-
perties, and on that account distinguished it by the name of cere-
brie acid. He found also in brain an acid to which he gave the
name of oleophosphoric ; which he considers as a compound of
olein and phosphoric acid. He extracted also oleic and marga-
ric acid from brain, and agrees with Vauquelin in admitting the
presence of a considerable quantity of albuminous matter. The
cephalote, stearoconote, and eleancepholote of Couerbe, M. Fremy
could not obtain. He considers them as mixtures of the differ-
ent oily acids contained in the brain, and differing in their pro-
perties, and in the proportion of their constituents according to
circumstances.
All that has hitherto been done towards an analysis of the brain
is to determine the nature of the substances which are taken up
from it by ether and alcohol. After the action of these substances
has been exhausted, the residual matter is almost as bulky as ever.
And this residual matter has not yet been subjected to exami-
nation. It consists, doubtless, of the minute varicose tubes de-
scribed by Ehrenberg. The nature of this matter has not hither-
to been determined ; but it contains a very great proportion of
water. Couerbe's analysis being the completest, it will be proper
to state the results which he obtained. The brain was in the first
place stripped off the coats which cover it, and washed in cold
water in order to deprive it as completely as possible of blood.
It was then reduced to pulp in a mortar and macerated in cold
ether. Four successive macerations were requisite to deprive the
brain of every thing which the ether was capable of dissolving.
Indeed the first maceration did little more than deprive it of wa-
ter. The ether being distilled off, and the residue dried in a
capsule to drive off the residue of ether, what remained was a
white fatty substance, partly in streaks and partly in grains.
When the brain thus treated was from a sound individual, almost
the whole of this matter was cerebrote. When the brain was
* Jour, de Pharm. xxvii. 453.
3
BRAIN AND NERVES.
that of an insane person, the cerebrote was combined with some
other substances. To separate them digest the fatty residue in
a little ether. Sometimes the cerebrote remains undissolved,
and may be obtained by passing the etherial solution through a
filter. When the ether dissolves the whole, as sometimes hap-
pens, we must evaporate to drive off the ether, and then subject
the white fatty matter to the action of boiling alcohol. The al-
cohol dissolves three different fatty bodies, one of which is cere-
brote, and leaves undissolved a sold brown substance resembling
wax.
When this brown substance is digested in ether, the greater
part of it is dissolved, but a brown powder remains, which Cou-
erbe has distinguished by the name of stearoconote.
The ether being evaporated, leaves a faun-coloured substance,
which cannot be sufficiently dried to assume the form of a pow-
der. To this brown matter Couerbe has given the name of ce-
phalote. It was first noticed by Kuhn ; but it is to Couerbe we
are indebted for the knowledge of its properties.
The alcoholic solution is filtered through animal charcoal,
and then left to itself. White fatty crystals are deposited, and
an additional quantity of them is obtained by concentrating the
liquid. These crystals being treated with ether, cerebrote is left
in a state of purity, while the ether dissolves a quantity of cho-
lesterin, which may be obtained in crystals by evaporating the
etherial liquid.
When the alcoholic liquid from which the crystals had been
deposited has been weakened by repeated concentrations, a red
oily matter begins to appear. To obtain this oil in a separate
state the liquid must be put into a linen cloth and squeezed. The
alcohol with the oil passes through the cloth, while the crystals,
consisting of cholesterin and cerebrote, remain. Add to the
muddy alcoholic liquid a little ether, which will dissolve the oil,
and render the liquid transparent. Set the solution aside. The
oil gradually subsides while the crystalline matter remains dis-
solved in the ether. When enough has subsided it may be puri-
fied by filtration. To this oil Couerbe has given the name of elean-
cephalote. *
* I think it right to state that I attempted to extract these various bodies,
described by Couerbe from the human brain ; but, with the exception of cere-
biote and cholesterin, I was unsuccessful.
SOLID PARTS OF ANIMALS.
The portion of brain which had been digested in ether was next
treated with boiling alcohol repeatedly, as long as any white matter
was deposited, when the alcohol cooled. This white matter was
cerebrate; the substance which had been already obtained by
Vauquelin by a similar process, and which he had distinguished
by the name of cerebral matter.
The brain deprived of these fatty matters has not materially
changed its appearance or its bulk. Vauquelin has shown that
this neurilema contains albumen and coagulated globules of a
membranous substance, soluble in potash. This substance, when
dried, assumes a gray colour, a semitransparence, and a fracture
similar to that of gum arabic. When put into water it becomes
opaque, swells up and softens, and water dissolves a very small
portion of it. Thus softened it readily dissolves in caustic potash
by the assistance of heat, and during the solution no ammonia
is disengaged. The potash solution is slightly brown, and has a
weak smell. The acids throw it down in white flocks, and dis-
engage a very fetid odour. When acetate of lead is dropt into
the solution, a dark brown precipitate falls, showing the presence
of sulphur. When cautiously distilled, it furnishes carbonate
of ammonia in crystals, and a red oil similar to that which al-
bumen yields when treated in the same way.
According to Vauquelin, the medulla oblongata and spinalis
are of the same nature with the brain, but contain much more
fatty matter, and less albumen, osmazome, and water. Hence,
the reason why the spinal marrow has greater consistence than
the brain. The portion insoluble in alcohol is albumen.
The nerves are likewise of the same nature as the brain, but
they contain much less fatty matter and much more albumen.
They contain besides common fat, which separates from them
when treated with boiling alcohol. When the nerves are de-
prived as much as possible of their fatty matter by alcohol, they
become transparent When digested in that state in boiling water,
they do not dissolve but become white, opaque, and swell up ob-
viously in consequence of absorbing moisture. The residue of
nerve which has been treated with alcohol and water dissolves
almost completely in caustic potash. No ammonia is evolved
during the solution. The potash solution is precipitated in pur-
ple flocks by acids.*
* Annals of Philosophy, i. 345.
4
MUSCLES.
CHAPTER IX.
OF MUSCLES.
THE muscles of man, and indeed of all the mammalia, birds,
and fishes, constitute by far the greatest part of the body. They
are the organs of motion, and constitute what in common lan-
guage is called jflesh. In man, the muscles are divisible into two
kinds, 1. Those which are attached to the bones, and 2. Those
of the viscera. The former, a few excepted, have a red colour
in warm-blooded animals, but are white in the greater number
of fishes. The latter are annular, as in the intestinal canal and
urinary bladder. They are usually pale, if we except the heart,
the muscles of which have the same colour as those attached to
the bones.
The muscles consist of a congeries of fibres, usually parallel
to each other. Each of these fibres, when viewed under the mi-
croscope, is composed of a number of smaller fibres, and the
smallest fibres of all, or what may be called the element of the
muscle, was believed by Leuwenhoek to be a congeries of sphe-
rical molecules, applied to each other so as to constitute a thread,*
and this opinion has been confirmed by subsequent observers.
These globules consist of fibrin. Every muscular fibre is en-
closed in a very delicate sheath of cellular substance, A num-
ber of these fibres associated together is covered and held toge-
ther by another delicate sheath of the same cellular substance.
Several of these are in their turn enveloped in a new common
sheath of the same substance. Thus, the whole muscle is com-
posed of numerous muscular fibres collected together in bundles,
and held together by connecting cellular substance. Hence it is
easier to tear these fibres from each other than to break them in
a direction perpendicular to their length.
The 'structure of muscle has been investigated with much care,
by Mr Skey,f who has confirmed the statements of Messrs
Hodgkin and Lister, that the ultimate filaments of muscle are
not composed of globules, but are hollow tubes, the size of which
does not exceed I7^^th of an inch. They are collected into
* Phil. Trans. 1677, Vol. xii. p. 899. f Phil. Trans. 1837, p. 871.
S
274 SOLID PARTS OF ANIMALS.
fibres about ^o th of an inch in diameter, and surrounded by cir-
cular striaB varying in thickness and in number. Each fibre is
divided into bands or fibrillae composed of many ultimate fila-
ments. Each fibrilla is divided into filaments, of which every
fibre of ¥^o th of an inch diameter contains about 100. The dia-
meter of the filaments is about one-third the size of the globules
of the blood.
Muscles, while they retain their vitality, contract when stimu-
lated either by the prick of any sharp instrument, or by the ap-
plication of any acrid or stimulating substance. When they lose
this property they are considered as dead. Sir Anthony Car-
lisle has shown that a muscle is stronger while it retains its irri-
tability, than when it has lost that property. He laid bare the
muscles of the two hind thighs of a frog, and removed the femoral
bone. He then attached weights to each set of muscles till it
was ruptured. The experiment was made upon the muscles of
one leg while they retained their irritability, and upon the mus-
cles of the other leg, after the irritability was gone. The mus-
cles retaining their irritability were ruptured by a weight of
six pounds avoirdupois ; those that had lost it by a weight of five
pounds.*
Through the muscular fibres run a great number of blood-
vessels and nerves. These may be removed to a certain extent,
but not completely. Especially the nerves, which are very nu-
merous, and which become at last transparent and invisible with-
out any sensible termination ; the cellular substance also which
surrounds the muscular fibres, and divides them into bundles, is
a substance of quite a different nature from the muscular fibre
itself, and would require to be removed before the chemical na-
ture of that fibre could be accurately determined. The red co-
lour of the muscle is doubtless owing to the existence in it, of a
vast number of capillary vessels filled with red blood.
The first attempt at a chemical examination of the muscles of
animals was by M. Claude-Joseph Geoffroy, Junior, in 1730.f
He examined the flesh of oxen, calves, sheep, fowls, pigeons,
pheasants, partridges, in order to determine how much of each
was soluble in water by boiling, and how much each lost when
dried over the steam-bath. The subject was farther continued
* Ptril. Trans. 1805, p. 3.
f Memoires de 1' Academic des Sciences, 1730, p. 217,
MUSCLES. 275
by him in 1832.* But chemical analyses were made at that
early period with so little attention to exactness, that it would
not be safe to trust to his results.
Towards the end of the eighteenth century, Thouvenel re-
peated some of the experiments of Geoffrey with more precision ;
and found that when flesh was boiled in water, not only gelatin
was dissolved, but likewise a particular extractive matter which
fixed his attention. About the year 1802, when Fourcroy pub-
lished his General System of Chemical Knowledge, he gave an
account of a set of experiments which he had made to analyze
the muscles of animals.! ThenardJ soon after examined the mat-
ter dissolved from the muscle by alcohol, and gave it the name of
osmazome. Mr Hatchett, in his Experiments on Zoophytes, publish-
ed in the Philosophical Transactions for 1800, (p. 327),has given
an account of numerous experiments on the component parts of
membranes, and, among other things which he examined, was the
muscular fibre of beef. He freed it as much as possible from
all foreign matter, and then examined it by means of different
reagents. Berzelius, in his Animal Chemistry, the second vo-
lume of which, containing his account of muscles, was printed in
1808, gives an account of an analysis which he had made of
muscle. Besides the substances previously detected by Four-
croy and Hatchett, he found also lactate of soda.§ He says in
his system that he discovered at the same time lactates of potash
and lime ;|| but I do not find any mention of these salts in his
Animal Chemistry. In 1821, Braconnot published an analysis of
the heart of an ox, in order to compare it with the excrements
of a nightingale which had been fed on that heart. 1 These, so
far as I know, are the only chemists who have examined the che-
mical characters and constitution of muscles.
Mr Hatchett took a piece of lean beef, cut it into thin small
pieces, and macerated it for fifteen days in cold water, sub-
jecting it each day to pressure, and changing the water. The
shreds of muscles, which amounted to about three pounds, were
then boiled with about six quarts of water during five hours, and
* Memoires de 1* Academic des Sciences, 1732, p. 17.
f Fourcroy's System, ix. 334. \ Traite de Chimie, iv. 613.
§ Djurkemien, ii. 170. || TraitS de Chimie, vii. 493.
] Ann. de Chim. et de Phys. xvii. 388.
276 SOLID PARTS OF ANIMALS.
the water being changed each time, the same boiling process was
repeated every day for three weeks ; at the end of which time
the water afforded only slight signs of gelatin when infusion of
oak bark or chloride of tin was added. After this the fibrous
part was well pressed, and was dried by the heat of the water-
bath. Muscle thus treated is as pure as it can be made by any
known process. The cold water removes the blood and lymph,
and the hot water dissolves the cellular substance, and converts
it into gelatin. The minute blood-vessels and nerves, which
cannot be separated mechanically, still remain.
Muscle thus treated contracts in its dimensions, has a dirty-
yellow colour, and is brittle, and easily reduced to powder.
Though steeped in water, it does not recover its former flexibi-
lity. 100 parts of muscle when dried are reduced to 17 parts,
so that the solid portion does not much exceed a sixth part
of the whole.
Muscle not boiled, when digested in acetic acid, is converted
into a jelly, which dissolves in water; but the solution is muddy,
and very difficult to filter. When the solution is left long at
rest, a quantity of fatty matter collects on the surface, and a
grey matter is deposited, consisting (probably) of minute blood-
vessels which have not dissolved in the acid.
Dilute caustic potash dissolves it when assisted by a gentle
heat. The solution is muddy, and can scarcely be filtered.
What remains undissolved is probably cellular matter, which
dissolves also when the temperature of the solvent in raised.
When muriatic acid is poured into the alkaline solution, a com-
pound of the acid and fibrin precipitates, which may be washed
in dilute muriatic acid ; but dissolves in water, becoming in the
first place gelatinous and transparent.
When washed muscle is exposed to pressure there exudes a
red liquid, which does not coagulate like blood, and which has
the property of strongly reddening litmus-paper. To obtain
the whole of this liquid we must digest the muscle in water.
This liquid was subjected to a chemical examination by Berze-
lius. He obtained,
1. Albumen. When the liquid is heated it becomes muddy at
122°, and a copious precipitate falls at 126°, in colourless flocks,
which are easily separated by the filter. This precipitate be-
comes white when washed The liquid from which the precipi-
MUSCLES. 277
tate fell has a deep red-colour like that of venous blood. At
134°, the greatest part of the matter which it holds in solution
coagulates, and if we keep it for half an hour at that tempera-
ture we obtain a colourless cake. At 144° another coagulum
falls, having a reddish gray colour ; but the colour of the liquid
from which it fell still continues unaltered. At a higher tem-
perature the colouring matter coagulates ; but its quantity is
very small compared to the preceding deposits. These different
precipitates indicate albumen, probably derived partly from the
blood circulating in the muscle, and partly from the nervous fi-
lament which it contains. The coagulating temperature is lower
than that of albumen in the serum of the blood. But that may
depend upon the acid present, or upon its state of dilution or
concentration.
The colourless coagulated albumen reddens litmus-paper, and
this property cannot be removed by washing. When dried its
colour becomes deeper, and at last almost quite black. Boil-
ing alcohol extracts from it a little fatty and a little animal
matter, which Berzelius considers as a combination of albu-
men with an acid. When long digested with water over
calcareous spar in powder a little lactate of lime is form-
ed. The liquid assumes a yellow colour, but holds in solu-
tion only a minute quantity of animal matter. This shows
that the precipitate from the liquid of muscle by heat is not ca-
sein. It dissolves readily in carbonate of potash, and the solu-
tion has all the characters of a solution of albumen.
2. Lactic acid. — If we filter the liquor from which the albu-
men has been separated by heat, and evaporate it to dryness, it
leaves a yellowish brown extract, more than the half of which is dis-
solved by alcohol of thespecific gravity 0-833. When thealcoholic
solution is evaporated to dryness there remains an extractiform
mass, mixed with crystals of common salt, which has a strongly
acid reaction ; but leaves when burnt some alkaline carbonate.
Hence- it follows that the matter contained a combustible acid,
partly free and partly combined with potash. If we mix the
alcoholic solution with a solution of tartaric acid in alcohol, there
separate bitartrates of potash and soda and tartrate of lime, and
there remains in solution in the liquid, besides tartaric acid and
muriatic acid, the combustible acid. If we digest the liquor with
carbonate of lead in fine powder till a portion of the lead re-
mains in solution the tartrate and chloride of lead precipitate. If
278 SOLID PARTS OF ANIMALS.
we evaporate the alcohol and dissolve the residue in water, and pass
through it a current of sulphuretted hydrogen gas to precipitate
the lead, and then boil the aqueous liquid with animal charcoal,
and evaporate, we obtain a colourless very acid syrup, possessing
all the characters of lactic acid.
3. Satis. — These are of two kinds ; namely, those which are
soluble in alcohol, and those which are only soluble in water.
The salts soluble in alcohol are the lactates of potash, soda,
lime, and magnesia, together with traces of lactate of ammonia,
likewise chloride of potassium and chloride of sodium. If we eva-
porate the alcoholic solution to dryness, and digest the residue
in absolute alcohol, the lactates will be dissolved, while the
chlorides will remain unacted on.
When the solution in absolute alcohol is treated with an al-
coholic solution of tartaric acid, the precipitate, when incinerated,
leaves a good deal of carbonate of potash and a little carbonate
of soda. These carbonates being dissolved, a white powder re-
mains, which dissolves with effervescence in muriatic acid, leav-
ing undissolved a trace of phosphate of lime. If we saturate the
solution with ammonia, oxalic acid precipitates the lime. The
lime being removed, phosphate of ammonia, mixed with a little
ammonia, throws down a small quantity of ammonia-phosphate
of magnesia.
The salts insoluble in alcohol are the phosphates of soda and
of lime.
4. Animal extractive matte?'. — This is partly soluble in alco-
hol of 0-833, and partly only in water.
(1.) The alcoholic extractive matter is what Thenard called
osmazome. It is a mixture of various substances ; among others
of lactic acids and lactates. When alcohol of 0-833 is digested
upon extract of flesh, it divides it into two nearly equal portions ;
the alcohol acquires a yellow colour, and leaves a brown viscid
matter, which is the portion soluble in water.
When the alcohol is distilled off, and the residue dried over
the steam-bath, there remains a transparent yellow matter mix-
ed with crystalline grains. When this matter is digested in ab-
solute alcohol, the greater portion of it is dissolved, and the so-
lution has a light colour and is transparent. If we distil off the
absolute alcohol, a syrup remains, which cannot be dried over the
steam-bath but remains semiliquid. It has an acrid and saline
taste. Its smell is at first similar to that of burnt bread, but
MUSCLES. 279
when kept, it exhales an urinous odour, especially when ammo-
nia is added to it When heated in an open dish it gives out a
very strong urinous smell ; it is then charred, and gives out a
smell exactly similar to that of burnt tartar, and finally swells
up, as happens to a vegetable acid united to an alkaline base. It
dissolves in water, and the solution has a yellow colour. Infu-
sion of nutgalls and corrosive sublimate throw down a very scan-
ty precipitate ; and this is the case also with acetate of lead and
nitrate of silver. Diacetate of lead throws down a very copious
precipitate ; oxalic acid throws down oxalate of lime ; lime- water
throws down nothing. But if we mix the extract with a good
deal of hydrate of lime, and boil for a long time, a disagreeable
ammoniacal smell is disengaged, the hydrate becomes yellow, and
a great proportion of the extract is decomposed. If it be now
treated with animal charcoal, little remains but lactic acid and
salts, which may then be separated. Nitric acid occasions the
formation of no nitrate of urea, but after some weeks crystals of
saltpetre make their appearance, from the decomposition of lac-
tate of potash.
The extractive matter soluble in absolute alcohol contains at
least two substances, which were separated from each other by
Berzelius in the following manner :
(1.) Corrosive sublimate threw down a yellow precipitate,
which was mixed with water, and a current of sulphuretted hy-
drogen passed through the mixture. A yellow solution remain-
ed, which had an acid reaction. When saturated with carbonate
of lead and evaporated, it left a deep yellow matter, from which
neither absolute alcohol nor alcohol of 0*833 is capable of dis-
solving the extractive which remains combined with the chloride
of lead. But it readily dissolves in water, and the solution is
precipitated by corrosive sublimate, but not by acetate of lead or
protochloride of tin, and very little by diacetate of lead. Ni-
trate of silver throws down the extractive matter combined with
chloride of silver. This portion of extractive matter possesses
the following properties : its colour while in solution is light-
yellow ; it has no taste, and has a great tendency to combine
with salts, on the nature of which depends its solubility or inso-
lubility in alcohol. Its compound with corrosive sublimate is
orange. It is slightly soluble in water, but not in water con-
taining an excess of corrosive sublimate. It is this substance^
280 SOLID PARTS OF ANIMALS.
which tannin precipitates from the extract obtained by anhydrous
alcohol. It constitutes but a small portion of that extract.
(2.) When diacetate of lead is poured into the liquid, which
has been precipitated by corrosive sublimate, and which contains
an excess of this last substance, a small quantity of a yellowish
precipitate falls quite similar to what urine furnishes in a similar
case. This precipitate consists of dichloride of lead with a little
dilactate of lead, both united to an extractive matter. If we wash
this precipitate and decompose it by sulphuretted hydrogen, we
obtain a yellowish liquid which has an acid reaction. If we sa-
turate this liquid with carbonate of lead, evaporate to dry ness,
digest the residual matter in alcohol, drive off the alcohol, and
decompose the residue by sulphuretted hydrogen and evaporate,
we obtain a yellow transparent matter, which contains a little
free lactic acid, exhales a weak urinous smell when evaporated,
and is not precipitated by any of the reactives above stated. It
combines with chloride of barium, and with other salts, precisely
as the corresponding matter from urine does.
The portion of the alcoholic extract insoluble in absolute al-
cohol is a viscid mass having a deep yellow colour, and general-
ly opaque. It is no longer completely soluble in alcohol of
0*833. That alcohol dissolves a portion of it, and assumes a yel-
low colour. When evaporated, it leaves an extract, mixed with
a combustible salt. It has no determinate taste. When heat-
ed cautiously till it begins to become brown, it gives out the
smell of roast-meat. If we now dissolve it in water, and treat it
with animal charcoal, most of the extract is separated from the
salt, which, after evaporation, remains in the state of a white mass,
consisting of soda and potash united to a combustible acid, but
without any salt of lime. The extractive matter when in solu-
tion is very slightly precipitated by infusion of nutgalls and cor-
rosive sublimate, and not at all by acetate of lead and protochloride
of tin. This extractive is the same as that which urine gives
under the same circumstances.
The portion which the alcohol of 0*833 leaves undissolved has
a deep-brown colour, and is mixed with crystals of common salt
It dissolves in water, and the solution has a brown colour. This
extract consists of two substances, one^of which is precipitated by
corrosive sublimate, and the other by protochloride of tin.
The precipitate by corrosive sublimate is deep-brown, and the
MUSCLES. 281
liquid over it is yellow. When decomposed by sulphuretted hy-
drogen, the residual liquid reacts as an acid. When concentrat-
ed to a certain point, the extractive which it contains may be pre-
cipitated by absolute alcohol, while the uncombined acid remains
in solution. It is a brown magma, having a slightly bitter taste.
It is soluble in water, and the solution has a brown colour. This
aqueous solution is copiously precipitated by infusion of nut-galls
and corrosive sublimate ; but not by acetate of lead, protochlo-
ride of tin, or nitrate of silver. Diacetate of lead precipitates it
abundantly. We obtain also a complete precipitate when, after
having added protochloride of tin, we pour in a quantity of caus-
tic ammonia.
When protochloride of tin is added to the yellow liquor which
has been already precipitated by corrosive sublimate, a new pre-
cipitate falls, which is colourless, and from which sulphuretted
hydrogen gas separates an almost colourless extractive, which is
tasteless, and exhales an animal odour when burnt. Its solution
is neither precipitated by acetate of lead nor infusion of nut-galls.
The quantity of it is inconsiderable.
(2.) Extractive Matter soluble in Water but not in Alcohol. —
Alcohol of 0-833 leaves a brown and opaque matter, having an
agreeable taste of meat or beef-tea. It has an acid reaction, and
contains lactic acid, which may be extracted in the following way :
Dissolve the extractive matter in water, saturate it with carbonate
of ammonia added in slight excess. Evaporate to the consistence
of a syrup, and mix the residue with alcohol of O833. The lac-
tate of ammonia, together with two extractive substances, will be
dissolved.
If we dissolve in water what remains after the evaporation of
the alcohol, and add infusion of nut-galls to the solution, a pre-
cipitate falls, which, though not quite insoluble in water, is yet
almost wholly separated by an excess of tannin. After having
collected this precipitate on a filter, and subjected it to pressure,
it is.soluble in boiling water, and the tannin may be separated
from it by acetate of lead. The precipitate being separated, and
the excfess of lead thrown down by sulphuretted hydrogen, the
liquid, when evaporated, leaves a yellow extractive matter, hav-
ing the smell and taste of toasted bread, and soluble in water, to
which it communicates a pale yellow colour. Its solution in wa-
ter gives a copious white precipitate with corrosive sublimate ;
282 SOLID PARTS OF ANIMALS.
a yellow precipitate with diacetate of lead and nitrate of silver.
Acetate of lead and protochloride of tin occasion no precipitates.
If we deprive the liquid which has been precipitated, by the
infusion of nut-galls, of its excess of tannin, by adding acetate of
lead, drop by drop, as long as a precipitate falls, and then eva-
porate the filtered liquor over the steam-bath, an acid extracti-
form matter remains, which contains lactate of ammonia. When
heated it gives out the smell of roast-meat. It is a mixture of
lactate of ammonia, and of a quantity of extract identical with
the portion left, when the matter dissolved by alcohol of 0-833
was digested in absolute alcohol.
The aqueous extract remaining after the preceding treatment
with carbonates of ammonia and alcohol of 0-833, contains at
least four different extractive substances. If we dissolve the
mass in water, and then add caustic ammonia, and afterwards
acetate of barytes, a precipitate of subphosphate of bary tes falls,
coloured brown by organic matter. A similar calcareous phos-
phate is precipitated by lime-water. If we wash the precipitate,
and digest it in a stoppered phial with weak caustic ammonia,
a portion of the organic matter is extracted, and a brownish yel-
low solution is formed, which, being filtered and evaporated to
dryness, leaves a brownish yellow matter, having the characte-
ristic taste of the aqueous extract. The barytic phosphate, how-
ever, still retains a portion of organic matter in combination.
The liquor from which this phosphate was precipitated, if it
contain a great excess of alkali, must be neutralized by acetic
acid. It is then to be completely precipitated by acetate of lead ;
saturating the acetic acid, as it becomes free, with ammonia.
The precipitate obtained is light and has a yellow colour. It is
to be collected on a filter, washed, mixed with water, and decom-
posed by sulphuretted hydrogen. The liquor thus treated must
be heated to allow the sulphuret of lead to precipitate. The
filtered liquor is brown, and this colour cannot be removed by
animal charcoal. It has an acid reaction, and contains a little
lactic and muriatic acids. We get rid of them by saturating
them with ammonia, evaporating to the consistence of a syrup,
and treating the matter with alcohol of 0*833. The ammonia-
cal salts are dissolved and the extractive matter remains.
It is a brown matter, which becomes hard when dried, and is
not altered by exposure to the air. It has a strong and agree-
MUSCLES. 283
able taste of beef-tea, exactly similar to that of the substance in-
to which fibrin is converted by boiling. It dissolves in all pro-
portions in water, and is precipitated by alcohol. Yet it com-
municates a yellow colour to alcohol of 0-833, which of
course dissolves a certain portion of it. Acetate of lead, proto-
chloride of tin, and nitrate of silver throw down brownish yellow
precipitates from its aqueous solution. It is not precipitated
by corrosive sublimate, and only very slightly by infusion of nut-
galls.
It is to this substance that boiled and roasted-meat owe their
flavour. Muscular fibre and cellular substance of themselves are
quite insipid, and the other extractive substances have but a very
slight taste. Berzelius proposes to distinguish this extractive
matter by the name of zomidin* Its characters are still very
imperfectly investigated, and it is not probable that it has been
obtained in a state of purity. Indeed, as most animal substan-
ces refuse to crystallize, we have no criterion by which we can
judge of their purity or impurity.
The liquor precipitated by acetate of lead gives with diacetate
of lead a new precipitate, which is almost colourless. If we de-
compose this precipitate by sulphuretted hydrogen, we obtain a
liquid nearly colourless, which, when evaporated, leaves a trans-
parent matter, similar in appearance to gum. When left to dry
in the open air it is easily detached from the glass vessel on
which it was placed. When burnt it gives out an acid smell.
Its taste is similar to that of gum. It softens in water before
dissolving^ and it dissolves in that liquid very readily. This so-
lution is not precipitated by acetate of lead, corrosive sublimate,
nor nitrate of silver. But diacetate of lead throws down a mu-
cous, colourless precipitate. Infusion of nut-gall renders it opal.
The liquid, which is no longer precipitated by the diacetate of
lead, is colourless, provided it be deprived of all lead and filtered.
When evaporated over the water-bath it becomes slightly yel-
low,' and leaves a yellow mass, mixed with a great quantity
of acetates. If we digest it in absolute alcohol to get rid of
the acetates, a yellow matter remains having the following pro-
perties : It is yellowish-brown, has very little taste, and gives
out animal odour when burnt. It dissolves easily in water, to
which it communicates a yellow colour, leaving a small quan-
* From £etmft<,iy broth.
284 SOLID PARTS OF ANIMALS.
tity of a yellow powder, similar to that ofapothem. Its solution is
not precipitated by corrosive sublimate, protochloride of tin, nor
acetate of lead. But with diacetate of lead it gives a copious preci-
pitate, which redissolves when acetate of lead is added. Nitrate
of silver throws down a yellowish grey precipitate, and infusion
of nut-galls renders it opal.
The solution in absolute alcohol is yellow, and contains a mat-
ter, which, being freed from alcohol and dissolved in water, is pre-
cipitable by infusion of nut-galls. If we dissolve this precipitate
in boiling water, precipitate the tannin by acetate of lead, throw
down the excess of lead by sulphuretted hydrogen, and filter and
evaporate the liquid, we obtain a transparent substance having
very little taste. Its aqueous solution is yellow, and exhibits
with reagents nearly the same characters as the preceding sub-
stances.
Such is an abstract of Berzelius's experiments on the expres-
sed juice of muscle. If we attend to the various vessels which
exist in muscle, arteries, veins, and lymphatics, it must be ob-
vious that a portion of these different substances must be derived
from the liquids contained in these vessels. But the liquids con-
tained in arteries, veins, and lymphatics are alkaline, while the
liquid from the muscle contains an excess of lactic acid, and
much more phosphate of lime than exists in blood or lymph. It
is not in our power, in the present state of our knowledge, to ex-
plain the origin of these matters, nor of the numerous extractive
matters which have been described. It is not unlikely that some
of the substances described by Berzelius may have been pro-
duced by the various processes to which the liquor of muscle
was subjected. Much light would be thrown on the subject by
the ultimate analysis of the different extractive substances, espe-
cially of that one which has the taste and smell of roasted-meat,
provided it could be obtained in a state of sufficient purity. Perhaps
the precipitate which it forms with oxide of lead or oxide of sil-
ver might enable a good experimenter to determine its atomic
weight and its ultimate constitution.
I am not aware that any muscles have been subjected to analy-
sis except those of the ox. Hatchett and Berzelius made their
experiments on the lean of beef, while Braconnot analyzed the
heart of an ox. The following table exhibits the result of the
analyses of Berzelius and Braconnot :
MUSCLES.
Berzelius.
Muscular fibre, vessels, and nerves, 15-8 \ 17.70
Cellular substance soluble by carbon, 1 -9 /
Soluble albumen and colouring matter, 2-20
Alcoholic extract with salts, . . 1*80
Aqueous extract with salts, . 1*05
Phosphate of lime containing albumen, 0-08
Water, . . 77-17
100-00*
Braconnot.
Fibrin, vessels, nerves, and cellular substances, 18-196
Albumen with colouring matter and phosphate of) 2 '7 33
lime and magnesia, . . /
Alcoholic extract, • • • 1*566
Lactate of potash, . . 0-186
Phosphate of potash, . . . 0-153
Common salt, . . . 0-126
Water, .... 77-036
100-OOOf
It is universally known that when flesh is left exposed to the
air, it runs into putrefaction very rapidly, giving out an exces-
sively disagreeable smell, and becoming soft and pulpy. But
in an air-tight vessel freed from oxygen gas, it may be kept for
years without any sensible alteration. In this way, it is often
exported from this country to India ; and I have eat beef per-
fectly fresh and good, after it had made a voyage to India and
back again.
The action of reagents on muscle is the same as on fibrin.
When very dilute acids are poured on flesh, a certain portion is
absorbed, the flesh becomes harder, and much less liable to pu-
trefaction. When the acids are stronger, the flesh swells out,
and is. converted into a jelly, which is soluble in water. Dilute
caustic alkalies dissolve flesh slowly ; but when they are concen-
trated, the solution is rapid. During the solution ammonia is
evolved, and a little alkaline sulphuret formed. Salts having an
alkaline base preserve flesh from putrefying. For this purpose
* Djurkemien, ii. 178. t Ann< de Chim. et de Phys. xxvii. 390.
SOLID PARTS OF ANIMALS.
common salt is usually employed. Several of the metalline salts
combine with flesh precisely as they do with fibrin. This is the
case with the salts of iron and mercury. It has long been known
that a very small quantity of corrosive sublimate preserves ana-
tomical preparations from putrefaction.
Muscles, it is well-known, are the organs by means of which
all the different motions of the living body are performed.
When a muscle acts the muscular fibres are shortened, while the
belly of the muscle swells out, and the whole muscle occupies a
greater bulk than before. Sir Anthony Carlisle introduced a
man's arm within a glass cylinder. It was duly closed at the
end which embraced the head of the humerus. The vessel being
inverted, water at 97° was poured in so as to fill it. A ground
brass plate closed the lower aperture, and a barometer tube com-
municated with the water at the bottom of the cylinder. This
apparatus, including the arm, was again inverted, so that the ba-
rometer tube became a gage, and no air was suffered to remain
in the apparatus. On the slightest action with the muscles of
the hand or forearm, the water ascended rapidly in the gage,
making librations of six and eight inches length in the barome-
ter tube, on each contraction and relaxation of the muscles.*
When muscles are strongly contracted their sensibility to pain
is nearly destroyed. This means is employed by jugglers for the
purpose of suffering pins to be thrust into the calf of the leg and
other muscular parts with impunity.f When fish are subjected
to the process called crimping, the specific gravity of the mus-
cles is increased. Crimping consists in cutting the muscles across
at various distances before their vitality is destroyed. The sea-
fish destined* for crimping are usually struck on the head when
caught, which, it is said, protracts the term of this capability ;
and the muscles which retain this property longest are those of
the head. Many transverse sections of the muscles being made,
and the fish immersed in cold water, the contractions called
crimping take place in about five minutes ; but if the mass be
large, it often requires thirty minutes to complete the process.
Sir Anthony Carlisle took two flounders, each weighing 1926
grains, the one being in a state for crimping, the other dead and
rigid. They were both immersed in water of 48° tempera-
* Phil. Trans. 1805, p. 22. f Ibid. p. 27.
4
MUSCLES. 287
ture after being equally scored with a knife. The specific gra-
vity of the crimped fish was 1*105, that of the dead fish, after a?,
equal immersion in water, 1*090.
A piece of cod-fish, weighing twelve pounds, gained in weight
by crimping two ounces avoirdupois, or rather more than one per
cent. ; and another less vivacious piece of fifteen pounds gained
one ounce and a-half. The hinder limb of a frog having the skin
stripped off, and weighing 77*1 grains, was immersed in water
of 54°, and suffered to remain nineteen hours. It became rigid,
and weighed 100*25 grains. So that the increase of weight amount-
ed to 30 per cent., while at the same time the specific gravity had
increased, as in the case of the crimped fish. 630 grains of the
subscapularis muscle of a calf, which had been killed two days
from the 1 Oth of January, were immersed in hard- water at 45°.
In ninety minutes the muscle was contracted, and weighed 770
grains. So that the increase of weight was rather more than
22 per cent. ; while, at the same time, the specific gravity of the
muscle had increased.*
Many attempts have been made to give a theory of muscular
motion ; but hitherto little satisfactory information on this intri-
cate subject has been suggested. One of the latest and most
ingenious theories on the subject is that of Prevost and Dumas.
According to them, the nervous filaments enter the muscles at
right angles, and, a'fter having traversed the muscular fibres turn
back and cross the same fibres in a direction parallel to their ori-
ginal one. A current of electricity passes through these nerves.
It moves in one direction in the first portion, and in the oppo-
site direction in the recurrent nerves. Hence the currents at-
tract each other, the muscular fibres are shortened, and muscular
motion produced. Before examining this theory, it would be ne-
cessary to establish by accurate anatomical dissections that the
direction of the nerves is as these philosophers allege.
* Carlisle, Phil. Trans. 1805, p. 23.
288 SOLID PARTS OF ANIMALS.
CHAPTER X.
OF TENDONS.
TENDONS are strong pearl-coloured bodies, which terminate
the muscles and attach them to the bones. They are known in
common language by the name of sinews. They are of very va-
rious forms, according to their situation. Some are narrow and
cord-like, as those which stretch across the wrist and ankle to
reach the fingers and toes. Others are compressed and strap-
shaped in the middle, and expanded at one or both extremities.
The tendo Achillis is convex on its cutaneous surface and flat on
the other, its fibres spreading out considerably where they run
into those of the muscle. The tendon of the plantaris is very
narrow and thin, but may be easily spread out to ten times its
natural breadth.
Tendons are composed of fibres. They are very strong, and
are so firmly united to the muscle to which they belong, that,
when rupture takes place in consequence of any sudden and vio-
lent action, the tendon itself gives way, and not its junction with
the muscle. Tendons are smooth, and are covered externally
with a kind of loose sheath of cellular substance, which facilitates
their motion on other bodies.
When a tendon has been softened in water, it may be spread
on the finger like a membrane, and has a silvery lustre. This
character enables us easily to distinguish the smallest tendons
from vessels and nerves.
The fibres are longitudinal, and differ much in their appear-
ance from cartilage, but I am not aware that they have been ever
subjected to a microscopical examination.
When put into boiling water, they swell, become yellow, and
semitransparent, and by long boiling they are dissolved and con-
verted into gelatin, which, on evaporation and drying, becomes
a firm glue. The transparency of the solution is impeded by
the presence of small vessels which float in it.
If we plunge a tendon into concentrated acetic acid, it swells,
becomes transparent and gelatinous. At the same time its sur-
face becomes uneven, and is twisted in various directions, and
when cut it presents an annular and angular division, owing pro-
LIGAMENTS. 289
bably to sheaths of cellular substance in the interior, and sur-
rounding the tendinous fibres. If we now pour water upon the
tendon thus altered, and make it boil, the tendon dissolves ra-
pidly, with the exception of the small vessels, which are inter-
spersed through it. The solution is similar to one of glue. It
is not precipitated by potash nor by prussiate of potash. The
same phenomena take place when tendons are treated with mu-
riatic acid and by caustic potash.
When tendons are dried they become hard, translucent, yel-
low, and similar to horn ; but they recover their former appear-
ance when softened in water. A long maceration in water re-
moves the cellular substance, and enables us to separate the ten-
dinous fibres from each other. But if we prolong the boiling,
these fibres themselves are dissolved and converted into jelly.
According to the analysis of Mulder and Scherer, the tendons
consist of protein combined with three atoms of ammonia, one
atom of water, and seven atoms of oxygen.
The tendons fix the muscles to the bones, and their fibres are
interlaced with those of the periosteum, a membrane which seems
to possess the same characters as the tendons. At least, like them,
it is converted by boiling into gelatin.
Aponeuroses are a kind of sheaths which inclose one or more
muscles, to which they serve as a kind of support, and of which
they increase the strength. Their tissue is similar to that of
tendons ; they possess both the characters and composition of
these bodies.
CHAPTER XL
OF LIGAMENTS.
LIGAMENTS are strong bands which bind the bones together
at the joints. Their form and size vary considerably in different
parts, some being flat bands, some rounded cords, and others
lengthened tubes attached by both ends to bones which admit of
free motion on one another, as we see in the capsular ligaments
of the hip and shoulder. Most ligaments enter into the forma-
tion of joints, and are therefore articular; though some, as the
interosseous ligaments in the fore-arm and leg, merely fill up
spaces.
SOLID PARTS OF ANIMALS.
As far as their chemical constitution is concerned, they may
be divided into two classes : One class, destined to oppose a great
resistance, becomes transparent when boiled, and is gradually
converted into gelatin. The ligaments belonging to the second
class are very elastic. This elasticity supplies the place of mus-
cular action, by enabling them, after being distended, to resume
their primitive size and shape. To this class belongs the liga-
ment of the neck, which supports the head of ruminating animals
and horses. The ligaments which draw back the claws in the
animals belonging to the genus felis, and also the yellow liga-
ments placed in man between the vertebrae, belong to the same
class. Anatomists were of opinion that these ligaments were of
the same nature as the fibrous membranes of the arteries ; and
this opinion has been confirmed by the experiments of Berzelius.
He found that when the yellow intervertebral ligaments are
heated they undergo a sort of semifusion. They swell up, and
after complete combustion leave a small quantity of white ash,
consisting principally of phosphate of lime. When these liga-
ments are boiled for a long time in water, during twelve or six-
teen hours for example, they do not become in the least soft, nor
do they undergo any alteration ; yet the water extracts a small
quantity of gelatin, derived, doubtless, from the cellular substance
mixed with the ligament. The ligament itself is neither dissolv-
ed nor softened, though kept for weeks in contact with alcohol,
ether, or concentrated acetic acid.
But it is dissolved slowly, without the application of heat, by
sulphuric, nitric, and muriatic acids. And the solutions, when
diluted with water, are not precipitated by potash or prussiate of
potash, but they are by the infusion of nut-galls. After having
been saturated by ammonia and evaporated to dryness, the muriatic
acid solution leaves a matter soluble both in water and in alco-
hol. The precipitate from the aqueous solution by infusion of
nut-galls is almost all soluble in boiling water and in alcohol.
The solution in acids takes place much more rapidly when
they are diluted and gently heated. The substance behaves in
the same way with caustic potash. When this last solution is
heated it gives the smell of dissolved horn. Acetic acid throws
:down from it a very slight precipitate. The matter which re-
mains after the saturated potash solution is evaporated to dryness
is soluble both in alcohol and water, and exhibits the same cha-
4
CELLULAR SUBSTANCE. , £91
racter as that from the muriatic solution. All these reactions
are the same as those of the fibrous coat of the arteries.
CHAPTER XII.
OF CELLULAR SUBSTANCE.
THE name cellular substance or tissue is given to a tissue
spread through the whole body, enveloping all the organs, and
filling up all the interstices, so as to leave no vacuities in the
body. It is made up of pale elastic and extremely fine filaments,
interwoven in different ways, so as to form areolse or spaces of
various size and figure, and calculated to contain such fluids as
may be deposited within them.
The quantity found in different parts varies considerably. In
some parts we trace it in the form of a thin layer lying beneath
the skin, and dipping into the interstices between the muscles.
It is accumulated in considerable quantity in the flexures of the
joints, filling up the popliteal space, the axillaB, and surrounding
the vessels at the groin. In the cavity of the abdomen a large
deposite is found, usually about the kidneys ; and in the pelvis
a loose spongy web fills up the spaces between the reflection of
the serous membrane and the different viscera. It may be said
that the cellular tissue of each region is continuous with that de-
posited in the neighbouring parts, and therefore forms a continu-
ous whole throughout the system.
The general opinion of anatomists at present is that the cel-
lular tissue is made up of cylindrical filaments, crossing in va-
rious ways, so as to form a net-work. These filaments in most
places are aggregated together so as to constitute lamellae, en-
closing spaces or cells, which present an infinite variety of forms
and of size ; but which still freely communicate, as is evident
from what happens in anasarca, and by the diffusion of air over
the body, in some cases of empyema.
The cellular tissue may be divided into two species. The first
species is more dense, and shows distinct cells. It is found in
the organs furnished with mucous membranes, the adhering face
of which it covers. The blood-vessels and nerves are also enve-
loped in it. The second species is softer, and contains cells
SOLID PARTS OF ANIMALS.
which communicate with each other. It fills up all the inter-
stices and penetrates into the muscles.
The cellular tissue consists of a matter which, when boiled in
water, becomes soft and mucilaginous, and is at last converted
into gelatin.
The cells of the cellular tissue are always moistened by a li-
quid secreted for the purpose ; and which in a state of health is
absorbed as fast as it accumulates. But in the disease called
anasarca or general dropsy this liquid is secreted probably in
greater abundance than in a state of health, while the absorbents
either cease to act, or act imperfectly. Hence the liquid accu-
mulates, fills all the cells, and constitutes the disease called dropsy.
In such cases it may be drawn off in considerable quantities. It
has been repeatedly subjected to a chemical examination. The
result of these analyses will be given in a succeeding chapter of
this work, while treating of lymph, to which liquid it obviously
belongs.
In some parts of the body the cells of the cellular tissue are
filled with fat. This is the case immediately under the skin,
constituting what is called the adipose tissue. Many anatomists,
however, consider the fat as enclosed in separate and shut vesi-
cles, which have no communication with each other. This opinion
is founded on the well known fact, that the fat of the spermaceti
whale is fluid, yet it does not collect in the lowermost cells of the
cellular tissue, as it would do if the cells or vesicles containing
it had a communication with each other like the cells of the cel-
lular tissue. Raspail even affirms that he can demonstrate the
vesicles in which the fat is contained. Obesity is considered by
some physiologists as a disease analogous to anasarca, with this
difference, that the cellular tissue is filled with fat instead of lymph.
CHAPTER XIII.
OF THE SKIN.
THE skin is that strong thick covering which envelopes the
whole external surface of animals. It is composed of three parts,
distinguished by different names, namely, 1. The cutis or true
skin, which is innermost and thickest. 2. The rete mucosum lies
SKIN. 293
immediately over the true skin, and is a thin membrane, to which
the colour of the body in man is owing. 3. The cuticle or epi-
dermis constitutes the outermost membrane, and is that part of
the skin which is raised in blisters. In this chapter we shall treat
only of the cutis or true skin. The other two membranes will
occupy our attention in the two following chapters.
The cutis or corium is a thick dense membrane composed of
fibres interwoven like the texture of a hat. When it is macerat-
ed for some hours in water, and agitation and pressure are em-
ployed to accelerate the effect, the blood and extraneous matter
are separated from it ; but its texture remains unaltered. The
fibres, after this maceration and softening, may be seen crossing
in various directions so as to enclose spaces. These are of con-
siderable size at the inner or attached surface of the membrane,
where granules of fat projected into them ; but gradually dimi-
nish towards the outer surface. The outer surface is not quite
smooth, but studded with a number of minute projections called
papilla. Each papilla appears to consist of the soft sentient ex-
tremity of a nerve, enclosed within a delicate vascular plexus,
possessing in some degree the properties of erectile tissue.
The cutis possesses elasticity to a certain extent, for after dis-
tension it retracts. The probability is that it resembles in its nature
the cartilages and serous membranes ; for when boiled a suffi-
cient time in water it dissolves, and is converted into gelatin.
If we suppose a piece of skin freed from the fat and cellular tis-
sue, which adheres to its interior side, and from the hair, epider-
mis, and papillae on its outer surface, it will contain, besides the
fibrous mass of which it is composed, and the vessels which pass
through it, a considerable quantity of liquid common to all the
soft parts of the living body. Wienholt made a set of experi-
ments to determine the proportion of these different substances,
and states them as follows :*
Cutaneous tissue proper and vessels, . 32-53
• Albumen, (liquid), ^ . 1-54
Extractive soluble in alcohol, . 0-83
Ditto soluble only in water, , 7-60
Water, . . . 57-50
100-00
* Berzelins, Trait^ de Chimie, vii. 298.
SOLID PARTS OF ANIMALS.
The liquid principles of the cutis may be extracted by water.
If we dry the skin after this treatment it becomes yellowish, trans-
lucent, and stiff but flexible and tough. Ether extracts from
it a good deal of fat. When macerated in water it recovers its
original softness. At the common temperature of the atmo-
sphere it is insoluble in water. When boiled in water it contracts,
becomes convex on the outside, thickens, becomes stiff and elas-
tic. But if the boiling be long continued it softens, becomes
mucous and translucent, and finally dissolves. The solution is
muddy from minute blood-vessels suspended in it. On cooling
the solution concretes into a jelly. Thus the cutis, by long
boiling, is converted into collin. The rapidity with which the
skins of different animals dissolve in boiling water is very differ-
ent The stronger, and larger, and older the animal is from
which the skins were obtained, the longer do they take to dis-
solve, but the stronger and stiffer is the glue into which they
are converted. The skins of fishes, of little birdsa of the small
mammalia dissolve readily. It is only necessary to keep them
in water of the temperature of 77°, to be converted into a kind
of jelly, which solidifies with difficulty, or remains half-liquid.
Skins are not dissolved by alcohol, ether, nor by the fixed or
volatile oils, whether hot or cold. But alkalies and acids diluted
to a certain point convert them into glue, even at the ordinary
temperature of the atmosphere. Thus, if we steep a skin in con-
centrated acetic acid, it swells into a jelly, which is soluble in
water. When a softened skin is steeped in persulphate of iron
or corrosive sublimate, it gradually combines with the metalline
salt, becomes more dense, harder, and incapable of putrefying.
A similar combination takes place when they are steeped in in-
fusion of oak-bark, or of any substance containing tannin.
It is from the skin or cutis of animals that leather is formed ;
and the goodness of the leather, or at least its strength, depends
in some measure on the toughness of the hides. Those easily
soluble, as seal-skins, afford a weaker leather than those which
are more difficultly soluble in water. The process by which the
skins of animals are converted into leather is called tanning. It
seems to have been known and practised in the earliest ages ; but
its nature was unknown till after the discovery of the tanning
principle by Seguin. That chemist ascertained that leather is a
compound of tannin and skin ; that it is to the tannin that lea-
SKIN. 295
ther owes its insolubility, and its power of resisting putrefaction.
The subject engaged the attention of Davy, who examined it
with his usual ingenuity, and added several important facts to
our former knowledge.
When skins are to be tanned, the first step of the process is to
deprive them of their hair and cuticle. This is either done by
steeping them in water till they begin to putrefy, or by steeping
them in lime and water. The lime seems to combine with the
cuticle, and to render it brittle and easily detachable from the
hide. It produces the same effect upon the hair and the matter
at its root. * When the hides have been steeped for a sufficient
time, they are taken out, the hair, cuticle, &c. scraped off, and
then they are washed in water.
After this preliminary process, the skins are subjected to diffe-
rent treatment, according to the kind of leather which is to be
made.
The large and thick hides are introduced for a short time into
a strong infusion of bark. They are then said to be coloured.
After this they are put into water slightly impregnated with sul-
phuric acid, or with the acid evolved during the fermentation of
barley and rye. This renders them harder and denser than they
were before, and fits them for forming sole leather. Davy thinks?
that, by this process, a triple compound is formed of the skin, tan,
and acid, f
The light skins of cows, those of calves, and all small skins,
are steeped for some days in a lixivium made by the infusion of
pigeon's dung in water. This lixivium is called the Drainer. By
this process they are rendered thinner and softer, and more pro-
per for making flexible leather. Davy considers the effect of this
lixivium to depend upon the fermentation which it undergoes ; for
dung that has undergone fermentation does not answer the pur-
pose |
After these preliminary processes, the skins are exposed to the
action of the infusion of bark till they are converted into leather.
The infusion of oak bark contains two ingredients, namely,
tannin and an extractive. The first is more soluble than the se-
cond. Hence, in saturated infusions, there is a much greater
proportion of tannin than of extractive ; whereas in weak infu-
* Davy, Journal of the Royal Instit. ii. 30. f Ibid. p. 31.
| Ibid. p. 32.
296 SOLID PARTS OF ANIMALS*
sions the extractive bears a greater proportion to the tannin.
Davy has ascertained, that the hides extract both the tannin and
extractive from the infusion, and leave nothing behind but pure
water, provided they be employed in sufficient quantity. Hence,
it is obvious, that both the tannin and extractive must enter into
the composition of leather. The extractive gives the hide a brown
colour, but does not render it insoluble in boiling water ; the tan-
nin renders it insoluble, but its colour continues whitish. Hence
it is likely that the lightest kinds of leather contain little else than
tannin, while the brown kinds contain both tannin and extractive,
and the new compound is leather. Hence the reason of the in-
crease of its weight.
Davy found that 100 of calf skin absorbed 64 in weight from
a concentrated infusion of nut-galls, and 34 from a concentrated
solution of oak bark ; 1 7 in a dilute solution of the same bark ;
34 in concentrated, and 15 in a dilute infusion of catechu. It
is generally admitted that 100 parts of skin, when tanned, be-
come 140 parts in weight.
Calf-skins, and those hides which are prepared by the grainer,
are first steeped in weak infusions of oak bark, and gradually re-
moved to stronger and stronger, till they are completely impreg-
nated, which takes up from two to four months. As the weak
infusions contain a greater proportion of extractive, the conse-
quence of this process is, that the skin combines in the first place
with a portion of it, and afterwards with the tannin. When sa-
turated solutions of tannin are employed, the leather is formed
in a much shorter time. This was the process recommended by
Seguin ; but it has been observed, that leather tanned in this way
is more rigid and more liable to crack than leather tanned in the
usual way. Hence it is likely, as Davy has observed, that the
union of the extractive is requisite to form pliable and tough lea-
ther. Leather rapidly tanned must be less equable in its texture
than leather slowly tanned, as the surface must be saturated with
tannin before the liquid has time to penetrate deep. Davy has
ascertained that skins, while tanning, seldom absorb more than
one-third of their weight of vegetable matter.
Skins intended for sole leather are generally kept from the
first in an infusion preserved nearly saturated by means of the
strata of bark with which they alternate. The full impregnation
requires from ten to eighteen months. It is likely, from this
SKIN. 297
process, that sole leather contains a greater proportion of tannin
than soft leather. While drying, it is smoothed with a rolling-
pin, and beat with a mallet, which must add considerably to its
density. *
The process of tawing is analogous to that of tanning. By it
the skins are converted into white leather, for gloves and other
similar uses. The skins are cleaned in the usual way, steeped in
lime-water, well scraped and beat with wooden pestles. They
are then steeped in water containing bran, which undergoing the
acetous fermentation, causes the skins to swell up and rise to the
surface. They are pushed down again, and the operation is re-
peated till the skins cease to rise. They are then washed, well
scraped, and for every hundred large sheep- skins, eight pounds
of alum and three pounds of common salt are put into water.
These two salts decompose each other. Sulphate of soda is
formed, and chloride of aluminum ; the last of which is imbibed
by the skins, and combines with them. Along with the alum
and salt is mixed with the water, while luke-warm, twenty
pounds of the finest wheat-flour, with the yolks of eight dozen
of eggs, all of which is formed into a paste a little thicker than
children's pap. A quantity of hot water is put into a trough,
and two spoonfuls of the paste with it, to do which they use a
wooden spoon, containing just as much as is required for a dozen
of skins, and when the whole is well mixed with the water, two
dozen of skins are plunged into it. Care must be taken that the
water be not too hot ; otherwise the skins are spoiled.
After the skins have lain some time in the trough, they are
taken out one by one with the hand, stretched out and well beaten
with wooden pestles. They are then left five or six days in a
vat, and hung out to dry on cords or racks, and the sooner they
are dried the better. Such are the most material parts of the
process of tawing, which consists essentially in combining the
skins with alumina, or more probably with dichloride of alumi-
num. Leather thus made is soft, pliable, and white.
* See Davy on the preparation of Skin for Tanning. Royal Instit Jour, ii,
30.
298 SOLID PARTS OF ANIMALS.
CHAPTER XIV.
OF THE EPIDERMIS.
THE epidermis or cuticle is the outer layer of the skin. Though
very thin in most parts, it becomes thick and indurated in the
soles of the feet, or wherever it is habitually subjected to pres-
ture. Its inner surface is smooth and uniform, being connect-
ed with the rete mucosum and corium by delicate filaments. But
it can be readily separated from them by decoction or macera-
sion in water. The outer surface presents in some places a num-
ber of waving excentric lines, which make it appear, when ex-
amined with a glass, ragged and uneven. It does not appear to
be composed of scales, as some anatomists have supposed ; but
rather to be a homogeneous membrane destitute of vessels and
nerves, and deposited on the skin as an insensible investment.
It is slightly elastic, and is easily ruptured. It wears away pretty
rapidly from all exposed parts, but is soon reproduced, and gra-
dually acquires its original thickness.
If we heat a portion of the cuticle in the flame of a candle
it melts without bending or swelling up, then catches fire, and
burns with a clear flame, giving out the usual smell of burning
animal matter. It imbibes water with facility. When the cu-
ticle of the palm of the hand is kept long in water, it swells up,
becomes wrinkled, opaque, and white. When left long in wa-
ter, it becomes brittle without putrefying ; but how long soever
we boil it in water it does not dissolve in that liquid.
If we let fall a drop of binoxide of hydrogen on any part of
the epidermis, it gives it a white colour, which disappears in a
few hours. The cuticle is insoluble in alcohol and ether, but
these liquids dissolve a small quantity of fatty matter, which the
epidermis in its natural state contains. Concentrated sulphuric
acid softens and gradually dissolves the cuticle. If we remove
the acid before it has dissolved the epidermis completely, it leaves
a dark brown spot. The part thus affected gradually becomes
hard and a new epidermis forms below it. When a piece of epi-
dermis is plunged into sulphuric acid, it becomes transparent
before it dissolves. Nitric acid softens it, and if we saturate the
excess of acid with ammonia, the stain acquires an orange colour.
EPIDERMIS. C299
which continues till the portion of cuticle thus affected comes off,
a new portion being formed under it
It is very easily dissolved in the caustic alkalies, even when
very dilute. The alkaline carbonates do not attack it. The
alkaline sulphurets give it a dark-brown almost black co-
lour, and the stain is not removed until the cuticle is renewed.
The chloride of gold tinges it purple. Nitrate of silver stains it
a chalky white, which on exposure to the light becomes gradu-
ally black. If the recent stain before becoming black be wash-
ed with caustic ammonia, the greatest part of the silver may be
removed. Parabanic acid and several other preparations from
uric acid stain it of a beautiful crimson colour.
Mr Hatchett has drawn as a conclusion from the characters of
the epidermis that it is quite analogous in its nature to coagulat-
ed albumen. How far this conjecture is correct can only be de-
termined by an ultimate analysis.
According to John,* the epidermis of the foot is composed of,
Indurated albumen, . 93 to 95
Mucus with trace of animal matter, 5
Lactic acid,
Lactate of potash,
Phosphate of potash,
Chloride of potassium,
Sulphate of lime,
Ammoniacal salt,
Phosphate of lime,
Manganese ? and iron
Soft fat, . . . 0-08
The epidermis of a woman affected with herpes was composed
of,
Indurated albumen, . 92 to 93
Mucus, . . 7 to 6
Lactic acid and the above stated salts, . 1
Soft fat, . 0-75 to 1
Dr Scherer subjected to analysis a portion of the epidermis
of the sole of the footf It was well washed with water, and then
boiled in alcohol and ether. When burnt it left one per cent, of
ashes. Abstracting the ashes its constituents were,
* Annals of Philosophy, ix. 55. f Ann- der Pharm. xl. 54.
300 SOLID PARTS OF ANIMALS.
Carbon, . 50-894
Hydrogen, . 6781
Azote, . 17-225
civ, 2- 25-100
Sulphur, *
100-
He represents its constitution (abstracting the sulphur) by the
formula C48 H39 Az7 O17. If we calculate from this formula
we get,
48 carbon, . =36 or per cent. 51-34
39 hydrogen, — 4-875 ... 6-95
7 azote, . 12-25 ... 17.47
17 oxygen, . =17- ... 24-24
70-125 100-
If from this formula, C48 H39 Az7 O17
we subtract protein, C48 H36 Az6 O14
there will remain, . H3 Az O3
which is an atom of ammonia -}- three atoms of oxygen.
CHAPTER XV.
OF THE RETE MUCOSUM.
THIS name has been applied by anatomists to a glairy exuda-
tion between the corium and cuticle, adhering to both, but parti-
cularly to the former. It is easily demonstrated in negroes ;
but much more difficultly in white men. On this account Bichat
and some other anatomists have denied its existence altogether.
But, on an attentive examination, it can generally be detected.
It was Malpighi who first drew the attention of anatomists to
this substance. He distinguished it from its appearance by the
name of mucous body ; and considered it as composed of soft fi-
bres so arranged as to form a net-work. Hence the origin of
the term rete mucosum. When a blister has been applied to the
skin of a negro, if it be not very stimulating, the cuticle alone
HAIRS AND FEATHERS. 301
will be raised in about twelve hours. After it is detached the
exposed surface appears covered with a dark coating. But if
the blister has been very active, another layer of a black colour
comes away with it. This is the rete mucosum, which gives to
the different races of men their various shades of colour.
The nature of this substance has not yet been determined.
Neither nerves nor blood-vessels have been traced into it. It
has been considered as a semifluid deposit or secretion. Some
suppose it to contain a black matter in the negro, similar to the
pigmentum nigrum of the eye. But the only chemical fact
connected with it that we know is inconsistent with this supposi-
tion. Chlorine deprives it of its black colour, and renders it yel-
low. A negro by keeping his foot for some time in water im-
pregnated with chlorine gas, deprived it of its black colour and
rendered it nearly white ; but in a few days the colour returned
again with its former intensity.* This experiment was first
made by Dr Beddoes on the fingers of a negro.f
CHAPTER XVI.
OF HAIR AND FEATHERS.
THESE substances cover different parts of animals, and are ob-
viously intended by Nature to protect them from the cold. For
this, their softness and pliability, and the slowness with which
they conduct heat, render them peculiarly proper.
1. Hair is usually distinguished into various kinds, according
to its size and appearance* The strongest and stiffest of all is
called bristle ; of this kind is the hair on the backs of hogs.
When remarkably fine, soft, and pliable, it is called wool ; and
the finest of all is known by the name of down. But all these
varieties resemble one another very closely in their composition.
Hair appears to be a kind of tube covered with a cuticle. Its
surface is not smooth, but either covered with scales or consist-
ing of imbricated cones. Hence the roughness of its feel, and
the disposition which it has to entangle itself, which has given
origin to the processes of felting and fulling. It is constantly in-
* Fourcroy, ix. 259. f Beddoes on Factitious Airs, p. 45.
302 SOLID PARTS OF ANIMALS.
creasing in length, being protruded from the roots, and seems at
first to be soft or nearly gelatinous. Every hair is a tube con-
taining a delicate organ, which supplies the hair with the requi-
site degree of moisture. In certain diseases, as the plica polo-
nica, this membrane swells so much that when the hair is cut, a
liquid, and even sometimes blood exudes. In their natural state,
the hairs are dry and insensible, and do not alter their appear-
ance by keeping.
When hair is boiled in water, a portion is dissolved. This
portion gelatinizes on the water cooling, and possesses the cha-
racters of gelatin. Hair thus treated becomes much more brit-
tle than before. Indeed, if the process be continued long enough,
the hair crumbles to pieces between the fingers. The portion in-
soluble in water possesses the properties of coagulated albumen.
Mr Hatchett has concluded from his experiments, that the
hair which loses its curl in moist weather, and which is the softest
and most flexible, is that which yields its gelatin most easily ;
whereas strong and elastic hair yields it with the greatest diffi-
culty, and in the smallest proportion. This conclusion has been
confirmed by a very considerable hair-merchant in London, who
assured him that the first kind of hair was much more injured by
boiling than the second.
Though hair be insoluble in boiling water, Vauquelin* obtain-
ed a solution by raising the temperature of the liquid in a Papin's
digester. If the heat thus produced was too great, the hair was
decomposed, and ammonia, carbonic acid, and an empyreumatic
oil formed. Sulphuretted hydrogen is always evolved, and its
quantity increases with the heat. When hair is thus dissolved in
water heated above the boiling point, the solution contains a kind
of bituminous oil, which is deposited very slowly. This oil was
black when the hair dissolved was black, but yellowish-red when
red hair was employed.
When the solution is filtered to get rid of this oil, the liquid
which passes through is nearly colourless. Copious precipitates
are formed in it by the infusion of nut-galls and chlorine. Silver
is blackened by it, and acetate of lead precipitated brown. Acids
render it turbid, but the precipitate is redissolved by adding
these liquids in excess. Though very much concentrated by
evaporation, it does not concrete into a jelly.
* Nicholson's Journal, xv. 141.
IIAIH AND FEATHERS. 303
Water containing only four per cent, of potash dissolves
hair, while hydrosulphuret of ammonia is evolved. If the hair
he black, a thick dark-coloured oil, with some sulphur and iron
remains undissolved ; if the hair be red there remains a yellow
oil, with some sulphur and an atom or two of iron. When acids
are dropped into this solution, they throw down a white matter
soluble in an excess of acid.
Sulphuric and muriatic acids become red when first poured on
hair, and gradually dissolve it. Nitric acid turns hair yellow and
dissolves it, while an oil separates, which is red or black accord-
ing to the colour of the hair dissolved. The solution yields a
great deal of oxalic acid, and contains, besides, bitter principle,
iron, and sulphuric acid. Chlorine first whitens hair, and then
reduces it to a substance of the consistence of turpentine, and
partly soluble in alcohol.
When alcohol is digested on black hair, it extracts from it two
kinds of oil. The first, which is white, subsides in white shining
scales as the liquor cools ; the second is obtained by evaporating
the alcohol. It has a greyish-green colour, and at last becomes
solid. From red hair alcohol likewise separates two oils : the
first white, as from black hair, and the other as red as blood.
When the red hair is deprived of this oil, it becomes of a chest-
nut colour. Hence its red colour is obviously owing to the
red oil.
When hair is incinerated, it yields iron and manganese, phos-
phate, sulphate, and carbonate of lime, muriate of soda, and a
considerable portion of silica. The ashes of red hair contain less
iron and manganese : those of white hair still less ; but in them
we find magnesia, which is wanting in the other varieties of hair.
The ashes of hair do not exceed 0*015 of the hair.
From the preceding experiments of Vauquelin, we learn that
black hair is composed of the nine following substances :
1. An animal matter constituting the greatest part.
- 2. A white solid oil, small in quantity.
3. A greyish-green oil, more abundant
4. Iron ; state unknown.
5. Oxide of manganese.
6. Phosphate of lime.
7. Carbonate of lime, very scanty.
8. Silica.
9. Sulphur.
304 SOLID PARTS OF ANIMALS.
The colouring matter of hair appears from Vauquelin's expe-
riments to be an oil. The oil is blackish-green in black hair, red
in red hair, and white in white hair. Vauquelin supposes that
sulphuretted iron contributes to the colour of dark hair ; and as-
cribes to the presence of an excess of sulphur the property which
white and red hair have of becoming black with the oxides of
the white metals. The sudden change of colour in hair from
grief, he thinks, is owing to the evolution of an acid.*
Vauquelin considers the animal matter of which hair is chiefly
composed as a variety of inspissated mucus ; but some of its pro-
perties, especially its copious precipitation by tannin, do not well
agree with that supposition. It seems to approach more closely
to coagulated albumen, as Hatchett has shown.
When hair is heated it melts, swells up, and gives out the
odour of burning horn. It burns with a strong flame, giving
out a great deal of smoke, and leaves a bulky charcoal. When
distilled per se, it gives one-fourth of its weight of empyreumatic
oil, water holding ammonia in solution and much inflammable
gas escapes, in which the smell of sulphuretted hydrogen may
be recognized. The charcoal remaining amounts to about one-
fourth of the weight of the hair. Different metalline salts pro-
duce the same change of colour on white hair as they do upon
the cuticle. We can dye white hair black by a solution of ni-
trate of silver in ether. But the best way of effecting that ob-
ject is to triturate the nitrate of silver with slacked lime, and to
make it up into a paste with hog's lard, which may be applied to
the hair without touching and blackening the skin. Another
substance commonly used to dye white hair black is protoxide of
lead in fine powder. One part of it is triturated with four parts
of slacked lime, and a weak solution of potash. A compound
of oxide of lead and potash is formed, which gradually penetrates
the hair, and sulphuret of lead is formed, which tinges the hair
black.
Dr Scherer subjected the hair of the beard to a chemical ana-
lysis.f It was first washed with water, and then boiled in alco-
hol and ether. Thus prepared, it left when burnt O72 per cent
of ashes. Its constituents were
* Nicholson's Journ. xv. 141, f Ann. der Pharm. xl. 55.
HAIR AND FEATHERS. 305
Carbon, . 50-417
Hydrogen, . 6-655
A/ote, . 17-936
Oxygen,
Sulphur,
100-000
He represents the constitution by the empirical formula C48
H39 Az7 O17. If, from this formula, we subtract that for pro-
tein, C48 H36 Az6 O14, there will remain H3 Az -f- O3, or an atom
of ammonia, and three atoms of oxygen.
Wool has not yet been subjected to a rigid examination ; but,
from the experiments made on it by Berthollet, there is reason
to conclude that its chemical qualities do not differ much
from those of hair. When growing upon the sheep it is enve-
loped in a kind of soapy matter, which protects it from the at-
tack of insects, and which is afterwards removed by scouring.
Vauquelin has examined this matter, and found it to consist of
the following ingredients : 1. A soap of potash ; 2. Carbonate of
potash ; 3. A little acetate of potash ; 4. Lime ; 5. A very lit-
tle muriate of potash ; and, 6. An animal matter.*
2. Feathers seem to possess very nearly the same properties
with hair. Mr Hatchett has ascertained that the quill is com-
posed chiefly of coagulated albumen. Though feathers were
boiled for a long time in water, Mr Hatchett could observe no
traces of gelatin.
Dr Scherer purified wool by washing it in water and then boil-
ing it in alcohol and ether, f It left 2 per cent, of ashes. Being
subjected to an ultimate analysis, it gave
Carbon, . 50'653
Hydrogen, . 7-029
Azote, . 17-710
Oxygen, )
Sulphur, j
100-
So that its composition is the same as that of hair. Feathers
were also subjected to an ultimate analysis by Dr Scherer. :f
* Ann. de Chim. xlvii. 267. f Ann. der Pharm. xl. 58.
\ Ann. der Pharm. xl. 61.
U
306 SOLID PARTS OF ANIMALS.
They contained 1-8 per cent, of ashes. The constituents obtain-
ed were
1. Of the soft downy portion.
Carbon, . 50-434 and 52-470
Hydrogen, . 7-110
Azote, . 17-682
Oxygen, . 24-774
100-000
2. The quill portion.
Carbon, . 52-427
Hydrogen, . 7-213
Azote, . 17-893
Oxygen, . 22-46
100-000
The constitution of both is obviously the same. Scherer repre-
sents it by the formula C48 H39 Az7 O16. By this formula they
contain an atom less of oxygen than hair or horns.
CHAPTER XVII.
OF HORNS, NAILS, AND SCALES.
Horns are well-known bodies attached to the foreheads of
oxen, sheep, and various other animals, and are obviously in-
tended for weapons of defence. They cover an elongation of
bone which rises from the os frontis. The portion of horny
matter nearest the forehead is the thinnest, and it constantly in-
creases in thickness as it advances to the extremity, where it is
thickest. It is translucent, and when very thin, has even a de-
gree of transparency, and has been used as a substitute for glass
in windows. Its colour is sometimes yellowish-grey, and some-
times almost black. It is capable of receiving a good polish, and
its lustre is resinous.
It is not very hard, and is easily rasped down by a file or rasp.
During this process it emits a disagreeable smell. When heated
a little above 212°, it becomes very soft, without undergoing de-
HORNS, NAILS, AND SCALES. 307
composition, so that it can be squeezed into a mould and wrought
into various forms, as is well known. When horns are distilled
per se they give out a great quantity of fetid oil, a little carbo-
nate of ammonia, together with a minute quantity of water. The
charcoal remaining in the retort amounts to about one-sixth of
the weight of the horns distilled. It has a semi-metallic lustre,
and when burnt leaves a quantity of white ashes constituting
about half a per cent, of the weight of the horns. It consists of
phosphate of lime with a little carbonate of lime and phosphate
of soda.
Horn is insoluble in water ; but when boiled for several days
in that liquid, it is softened, and the water is slightly precipitated
by chloride of tin, but not by tannin. When horn is strongly
heated with water in a Papin's digester, it is said to be convert-
ed into a gelatinous mass which possesses the properties of gela-
tin. Horn is insoluble in alcohol and ether. These liquids, how-
ever, separate a small quantity of fatty matter.
Concentrated sulphuric acid, at the temperature of 57°, does
not dissolve horn nor acquire any colour from it. But the horn
is softened by the acid. If we wash it with water, and then boil
it in that liquid, a portion of it is dissolved, and the liquid is pre-
cipitated by corrosive sublimate and infusion of nut-galls. Di-
lute nitric acid softens horn ; but a long maceration is required
before this effect is produced. If we pour ammonia on the sof-
tened horn it becomes first reddish-yellow, then blood-red, and
finally dissolves into a dark -yellowish red liquor. If we wash
horn softened by nitric acid with cold water, and then boil it in
a new quantity of water, it dissolves, forming a yellow liquid,
which gelatinizes on cooling. This jelly is dissolved by cold
water, and the solution is precipitated by tannin. Concentrated
nitric acid dissolves horn. If we evaporate the solution to dry-
ness, it detonates. Horn is not softened when macerated in
concentrated acetic acid. But when it is digested for some days
in a close vessel in dilute acetic acid, that liquid dissolves a portion
of it without becoming coloured, and when the liquid is evapo-
rated to dryness, a light-yellow substance remains, which is tran-
sparent, and not soluble in water.
If, after freeing horn from fat by means of alcohol, we dry it,
and pour over it concentrated muriatic acid, after an interval of
a day or two it becomes blue, though the acid acquires no colour,
308 SOLID PARTS OF ANIMALS,,'
Nitric acid changes the blue colour to yellow, and ammonia to
orange.
The caustic fixed alkalies dissolve horn easily ; but ammonia
does not attack it
If, after freeing horn from fat by means of alcohol, we place
it in contact with very dilute caustic potash, the liquid acquires
a disagreeable smell, and the horn assumes the form of a jelly,
and gradually dissolves. The liquid is pale-yellow, and can
hardly be filtered. When a concentrated solution of caustic po-
tash is poured upon raspings of horn a very disagreeable smell
is evolved, and the raspings gradually soften into a matter like
glue, grey-coloured and semitransparent. The alkaline liquid
has a deep-yellow colour, and gives traces of ammonia. The
viscid mass is a combination of the horn with the potash. It is
insoluble in the concentrated alkaline liquor while cold ; but dis-
solves in it when assisted by heat. We pour the alkaline ley
from the viscid mass, and wash it with cold water. Thus treated,
it dissolves in water without communicating any colour. The
solution has an alkaline reaction. When acetic acid is poured
into it in such quantity as not to decompose it completely, a
white curdy precipitate falls, which soon collects into a viscid
gluey mass. It is a compound of horn with a minimum of al-
kali. If we decant off the saline solution which floats over it,
and then pour water on it, it gradually gelatinizes, and at last
dissolves into a mucilage decomposable by acids. If, on the
contrary, we add enough of acetic acid to decompose the whole
compound of horn and potash, and to leave a surplus of acid in
the liquid, a precipitate falls quite similar to the former in ap-
pearance, but which is a compound of horn and acetic acid. It
is insoluble in water, whether cold or hot, and also in alcohol.
But it is soluble in acetic acid, Prussiate of potash throws down
from this solution semitransparent flocks, which subside very
slowly to the bottom of the vessel. Carbonate of ammonia gives
a precipitate soluble in a great excess of the reagent. Corrosive
sublimate, acetate of lead, persulphate of iron and tannin, throw
down abundant precipitates.
If we evaporate the acetic acid solution to dryness, we obtain
a yellow, transparent, hard, and viscid mass, which is insoluble in
water. When we evaporate to dryness the solution precipitated
by acetic acid, and digest the residue in water, a portion of horn
HORNS, NAILS, AND SCALES. 309
remains, but the liquid contains a little, which behaves with re-
agents in the same way as the acid solution.
When, instead of acetic acid, we employ muriatic acid to throw
down horn from potash, the precipitate obtained is more abun-
dant, because it is less soluble in the excess of muriatic acid ad-
ded. This precipitate constitutes a coherent mass ; but if we
wash it and then digest it in water, it dissolves and produces a
milky liquor, which, by the addition of an additional quantity of
acid, produces a viscid and acid precipitate.
Berzelius considers horn as a modification of fibrin. He founds
his opinions on the circumstances, that its acid solution is preci-
pitated by prussiate of potash ; that horn remains dissolved in
acetic acid ; and that its neutral combination with muriatic acid,
which is partially soluble in water, coagulates anew when an ad-
ditional quantity of muriatic acid is added.
If we boil horn with a concentrated solution of potash, it sof-
tens and then dissolves, while abundance of ammonia is given
out, which has a very disagreeable smell. This disengagement
continues for a long time. The portion of horn not dissolved is
softened, and it becomes so slippery that, if we take it out of the
liquid, we can scarcely hold it in our fingers. If we wash it in
cold water to remove the alkali it dissolves in the liquid with-
out communicating to it any colour.
The solution of horn in boiling potash is thick, of a dark-
brown colour, and similar to a bad potash soap. It dissolves
easily in water, forming a muddy solution, which, when filtered,
is pale yellow, leaving a minute quantity of deep-green powder,
which Berzelius considers as sulphuret of iron. Its dark colour
vanishes when the powder is exposed to the air. If we mix the
alkaline liquor with an acid, carbonic acid is disengaged mixed
with sulphuretted hydrogen gas. If the acid added be muria-
tic, after the carbonic acid is disengaged, a compound of the acid
and horn, the same as described above, falls down ; but in small
quantity compared to that of the horn acted upon. If we digest the
acid liquor from which this precipitate has fallen over carbonate of
lime till it is neutralized, and then evaporate the whole todryness,
and digest the dry residue in alcohol, to dissolve the chloride of
calcium, a matter remains which dissolves readily in water, to which
it communicates a pale-yellow colour. When this solution is
evaporated to dryness it leaves a hard transparent matter, which
310 SOLID PARTS OF ANIMALS.
may be reduced to powder with the greatest facility. The
aqueous solution of this substance is precipitated by the same re-
agents as the acetic solution of horn. But prussiate of potash
does not render it muddy unless acetic acid be previously added.
This substance is a compound of the horny matter and lime.
The lime remains behind when we burn the compound. Muri-
atic acid throws down a precipitate from its solution in water,
which is redissolved by the addition of a greater quantity of
acid. Acetic acid throws down a precipitate which requires for
solution a very large quantity of free acid.
Jt is evident from these facts that when potash is made to act
upon horn, a decomposition takes place ; the horn being convert-
ed into carbonic acid, ammonia, sulphuretted hydrogen, and a
substance soluble in muriatic acid and water, with a minimum of
alkali ; while another portion of matter remains insoluble com-
bined with an excess of muriatic acid.
Dr John, a great many years ago, made an analysis of the horns
of oxen. He extracted from them the following constituents :
Indurated albumen, . . 90
Gelatinous albumen with osmazome ? . 8
Lactic acid,
Lactate of potash,
Sulphate, muriate, and phosphate of potash,
Phosphate of lime,
Oxide of iron, trace,
Ammoniacal salt, . . J
Fat, . . 1
100*
The quantity of earthy matter contained in horns is exceed-
ingly small. Mr Hatchett burnt 500 grains of ox horn. The
residuum was only 1.5 grain, and not the half of this was phos-
phate of lime. 78 grains of the horn of chamois left only 0-5 of
residue, of which less than the half was phosphate of lime.f They
consist chiefly of a membranous substance, which possesses the
properties of coagulated albumen ; and probably they contain also
a little gelatin. Hence we see the reason of the products that
are obtained when these substances are subjected to distillation.
Dr Scherer subjected the horn of the buffalo to a chemical
analysis.:]: It was purified by washing it with water and boiling
* Annals of Philosophy, ix. 55. f Phil, trans. 1 799, p. 332.
\ Ann. der Phtirm. xl. 56.
HORNS, NAILS, AND SCALES. 311
it in alcohol and ether. When burnt it left 0*7 per cent, of
ashes. Its constituents were,
Carbon, . 51-578
Hydrogen, . 6-712
Azote, . 17-284
Oxygen, |
Sulphur, /
100-
He gives us an empirical formula, C48 H34 Az7 O17. So that
its constitution is the same as that of hair, namely, one atom
protein -f one atom ammonia + three atoms oxygen.
If we precipitate an alkaline solution of hair or horn with
acetic acid, sulphuretted hydrogen escapes and a precipitate falls,
which is soluble in acetic acid, and possesses the characters and
constitution of protein.
The nails, which cover the extremities of the fingers, are at-
tached to the epidermis, and come off along with it. Mr Hat-
chett has ascertained that they are composed chiefly of a mem-
branous substance, which possesses the properties of coagulated
albumen. They seem to contain also a little phosphate of lime.
Water softens but does not dissolve them ; but they are readily
dissolved and decomposed by concentrated acids and alkalies.
Hence it appears that nails agree with horn in their nature and
composition. Under the head of nails must be comprehended the
talons and claws of the inferior animals, and likewise their hoofs,
which differ in no respect from horn.
The substance called tortoise-shell is very different from shells
in its composition, and approaches much nearer to the nature of
nail ; for that reason I have placed it here. When long mace-
rated in nitric acid, it softens, and appears to be composed of
membranes laid over each other, and possessing the properties of
coagulated albumen. When burnt, 500 grains of it yield three
of earthy matter, consisting of phosphate of lime and soda, with a
little iron.*
The scales of animals are of two kinds ; some, as those of
serpents and other amphibious animals, have a striking resem-
blance to horn ; while those of fish bear a greater resemblance to
mother-of-pearl. The composition of these two kinds of shells
is very different
* Hatchett, Phil, Trans. 1799, p. 332.
SOLID PARTS OF ANIMALS.
The scales of fish, as had been observed by Lewenhoeck, are
composed of different membranous lamina?. When immersed
for four or five hours in nitric acid, they become transparent and
perfectly membranaceous. The acid, when saturated with am-
monia, gives a copious precipitate of phosphate of lime.* Hence
they are composed of alternate layers of membrane and phos-
phate of lime. To this structure they owe their brilliancy. Mr
Hatchett found the spicula of the shark's skin to be similar in its
composition, but the skin itself yielded no phosphate of lime.
The horny scales of serpents, on the other hand, are compos-
ed alone of a horny membrane, and are destitute of phosphate of
lime. They yield, when boiled, but slight traces of gelatin ; the
horn-like crusts which cover certain insects and other animals
appear, from Mr Hatchett's experiments, to be nearly similar in
their composition and nature.
Thus it appears that these substances bear a striking resem-
blance to each other, being composed of a membrane which
Hatchett considers as coagulated albumen. Vauquelin, however,
who affirms that they dissolve in water, provided the temperature
be raised sufficiently in a digester above the boiling point, consi-
ders them, on that account, rather as a species of concrete mucus
than as coagulated albumen, f
CHAPTER XVIII.
OF HARTSHORN.
THE horns of the buck and hart, and indeed of the whole
tribe of deer, are quite different from those which have been
treated of in the last chapter. They are branched, and possess
the hardness of bone. From the experiments of Scheele and
Rouelle, together with those of Hatchett, we know that these
substances possess exactly the properties of bone, and are com-
posed of the same constituents, excepting only that the propor-
tion of cartilage is greater. They are intermediate, then, be-
tween bone and horn. The same remarks apply to a fossil horn
* Hatchett, Phil. Trans, 1799, p. 332. f Nicholson's Jour. xv. 147.
3
SEROUS MEMBRANES. 313
found in France, and analyzed by Braconnot. He found it com-
posed of
Silicious sand, . 4*0
Gelatin, . .4-6
Bitumen, . . 4'4
Oxide of iron, . 0*5
Alumina, . . 0*7
Phosphate of magnesia, . 1 '0
Water, . . 1]-0
Carbonate of lime, . 4*5
Phosphate of lime, . 6 9 '3
100-0 *
CHAPTER XIX.
OF SEROUS MEMBRANES.
THE name serous membranes is applied to certain thin, pellu-
cid, and transparent tissues, which constitute shut sacs without
inlet or other interruption of continuity. They are called serous,
because they are constantly moistened by a thin albuminous
fluid, supposed to resemble the serum of blood. These serous
membranes in the human body are chiefly the following : 1. The
arachnoid membrane, which invests the brain, and which is pro-
longed over the spinal chord : 2. The two pleurce, which invest
the lungs; 3. The pericardium, which incloses the heart; 4.
The peritoneum, which is reflected over the different viscera of
the abdomen, together with the two processes which extend from
it upon the testes ; 5. The membrane which lines the anterior
chamber of the eye. Perhaps the lining coat of arteries and veins
may also be referred to the serous membranes.
These membranes invest the viscera, which they inclose, and
are likewise reflected upon the walls of the cavity. It is the in-
vesting part of the serous membranes that gives to different or-
gans their shining appearance ; and as the membrane is very
thin and transparent, the colour, form, and even the minute in-
* Gehlen's Jour, second series, iii. 49.
SOLID PARTS OF ANIMALS.
equalities in the surface of these organs may be distinctly seen
through the serous membranes that invest them.
Serous membranes are capable of very considerable distension,
as is obvious in dropsy and in the various hernia? of the intestines.
In their natural state they are insensible or nearly so ; but when
they are inflamed, acute pain is felt in them. As they pass from
one viscus to another, it is obvious that they must form folds ;
and these folds have been often distinguished by names, as amen-
tum, mesentery., mesocolon, mediastinum, &c.
Blood-vessels may be seen entering into the serous membranes
in cases of inflammation. Hence it follows that they are supplied
with arteries and veins. Whether they possess exhalent vessels
to throw out the serum or lymph with which they are moistened,
has not been ascertained.
As to the chemical nature and properties of the serous mem-
branes, no experiments, so far as I know, have hitherto been
made upon the subject. It is stated in chemical books that when
boiled in water they are converted into collin. Hence it has
been inferred that they are merely inspissated cellular membrane.
But I am not aware of any person having tried the experiment.
It is certain that the small intestines may be boiled for a long
time without being deprived of their outer serous coat, and with-
out that coat undergoing any sensible change.
The liquid exhaled from the surface of the serous membranes
will be described, and its constituents stated in a succeeding
chapter of this work when treating of lymph.
CHAPTER XX.
OF MUCOUS MEMBRANES.
THE mucous membrane, in an anatomical point of view, may
be considered as one continuous membrane prolonged from the
integuments into the interior of the passages of the body, where
it serves a corresponding purpose with the skin ; but which, from
the nature of the fluid which it secretes, and which covers it, has
received the name of mucous membrane. From the lips and nos-
trils it extends along the whole length of the alimentary canal as
well as into the different follicles and excretory ducts which open
MUCOUS MEMBRANES. 315
into it. The larynx, trachea, bronchia, and air-cells of the lungs
are lined with mucous membrane. A similar mucous surface
may be traced from the opening of the urinary canal along the
urethra, bladder, and ureters, to their termination in the calyces
of the kidney ; also into the vasa deferenlia. In the female it
is prolonged from the vagina into the uterus and the Fallopian
tubes to their termination.
Between these two great divisions of the internal integuments
no organic connection exists. Each may be viewed as a canal
of considerable extent, but presenting numerous contractions and
dilatations corresponding with those of the hollow organs which
they line. Their external surface is rough and flocculent, being
attached by cellular tissue to the contiguous textures. The firm-
ness of this attachment varies in different places. In the sto-
mach the mucous membrane is easily separated. From the py-
lorus to the ileo-csecal valve it gradually becomes more firmly
attached, and in the large intestines it adheres very closely to the
next coat below it till towards the extremity of the rectum, where
it is again loose.
The thickness of this membrane is equally various. It is thick-
est in the stomach and duodenum, and thence diminishes gra-
dually towards the lower part of the small intestines. At the
ileo-csecal valve it increases somewhat, and in the large intestines
it is only about half as thick as in the stomach ; but it increases
towards the extremity of the rectum. Its firmness and power of
resistance is greatest in the stomach.
The colour of the mucous membrane varies in different parts
of its extent. It is influenced also by the age of the individual,
and doubtless by the disease of which he died. When freed from
cellular tissue and mucus it is translucent and white, or grayish,
with a delicate rosy tinge. This tinge is owing to the blood-
vessels with which it is supplied. It deepens in the stomach
during the digestive process, doubtless because the quantity of
blood conveyed to it is then greatest.
The plicae and valvula conniventes of this membrane are well-
known 'to anatomists. When viewed with a microscope it is
found covered with a vast number of minute downy processes,
giving it a flocky appearance. These have been called villi.
These villi are generally considered as ducts which secrete the
gastric juice when it is required for the purpose of digestion.
3lG SOLID PARTS OF ANIMALS.
The mucous membrane, though apparently a continuation of
the skin, differs entirely from that tissue in its chemical proper-
ties. It is quite insoluble in water. When long boiled in that
liquid it becomes hard and brittle. Acids easily destroy it, and
convert it into a pap. It readily putrefies, and in that way its
texture is speedily destroyed. If we soften it in cold water, and
leave it in that state to the action of the atmosphere, it is con-
verted into a reddish mucous-looking substance before the other
coats of the intestines have begun to be affected.
The mucous membrane, like the cutis, is covered by a very
thin epidermis, to which the term epithelium has been applied.
The chemical nature of this membrane has not been determined ;
but it is probably of the same nature with the epidermis.
CHAPTER XXI.
OF ARTERIES AND VEINS.
L THE term artery* meant originally a tube containing air.
It was not till after the discovery of the circulation by Hervey
that their use was fully understood. They are tubes which con-
vey the blood from the heart to every part of the body, in order
to supply the waste of the system ; while the veins convey back
again to the heart all the blood which has not been consumed by
the different processes going on in every part of the body.
An artery is a cylindrical and highly elastic tube, composed
of three coats placed one within the other. The external coat is
formed of the cellular tissue, into which it may be resolved by
maceration. Its texture is closer when it is in contact with the
middle coat, than externally when it is somewhat loose and floc-
culent It admits of considerable extension, and can retract
when the cause is removed, and it is so tough as not to be divided
by a hard ligature placed on the vessel, and so firm as alone to
resist the impulse of the current of blood, when the other coats
are divided or torn.
The internal coat not only lines the arteries, but is continued
into the ventricles of the heart It is thin, homogeneous, trans-
parent, and so fragile as to be easily torn. It is considered by
* From ttHf, air, and T»fiu>, / contain.
ARTERIES AND VEINS. 317
anatomists, as similar to the serous membranes, though I am not
aware that any experiments have been made to determine the
point
The middle coat is the principal one, and the one to which the
arteries are chiefly indebted for their peculiar characters. It
consists of pale, straw-coloured fibres, coiled obliquely round the
circumference of the vessels, but none of them forming a com-
plete circle. If an artery be stretched transversely it will recoil
and resume its original diameter. If elongated it will retract.
We see from this that arteries are highly elastic, and this pro-
perty they owe chiefly to the middle coat, which is strong and
dense. When an artery no longer carries blood, as after a li-
gature has been applied to it, the part beyond the ligature will
retract, its cavity will be obliterated, and, by an alteration in its
mode of nutrition, will degenerate into a fibrous cord. This in-
dicates a contractile power differing from mere elasticity, and has
been termed contractility of tissue. Anatomists long ascribed
muscular properties to this middle arterial coat ; but the chemi-
cal properties which it possesses are incompatible with this no-
tion.
The middle arterial coat is quite insoluble in water, even when
long boiled in that liquid. When concentrated acetic acid is
poured on it, it neither softens nor dissolves ; nor do we obtain
any solution even when we boil it in dilute acetic acid. But it
dissolves with great ease in sulphuric, nitric, and muriatic acids,
even when much diluted with water. The solution is neither
precipitated by an alkali nor by prussiate of potash, as is the
case with fibrin, and with muscular fibre treated in the same way.
The middle arterial coat is dissolved by caustic potash. The
solution is colourless, but slightly muddy ; and it is not precipi-
tated by acids. If we mix together saturated solutions of the
middle coat of an artery in potash, and in an acid, the mixture
becomes gradually muddy, and a precipitate falls.
This middle coat, after having been purified by solution in di-
lute potash ley and precipitation by an acid, was subjected to
analysis by Dr Scherer. * When burnt it left an ash weighing
1-7 per cent. Its constituents (abstracting the ash) were found
to be
* Ann. der Pharm. xl. 51.
318 SOLID PARTS OF ANIMALS.
Carbon, . 53-571
Hydrogen, . 7-026
Azote, . 15-360
Oxygen, . 24-043
100.000
He represents its constitution by the empirical formula,
C48 H38 Az6 O16. If from this formula
we abstract C48 H36 Az6 O14, the formula for pro-
tein, there will remain H2 O2, or two atoms of wa-
ter. So that the middle coat of arteries may be represented by
1 atom protein + 2 atoms water.
IL The veins, like the arteries, are composed of three coats ;
but they are much thinner and more flaccid than the correspond-
ing arterial coats. They are easily distended, admitting of con-
siderable enlargement in the transverse direction. They are al-
so susceptible of elongation, but not to the same extent as the
arteries.
The external venous coat, like that of the arteries, consists of
cellular tissue, but is much thinner and less firm than that of the
arteries. It is very closely united to the middle coat.
The internal coat is a thin shining membrane continuous with
that which lines the auricles of the heart. It is here and there
thrown into folds which constitute valves. It is considered by
anatomists as similar in its nature to the serous membranes ;
though I am not aware of any experiment to elucidate the point.
The middle coat of the veins is thinner and much more pliant
than that of the arteries. It appears at first sight smooth and
even in its texture and destitute of fibres. But a more careful
inspection shows that it consists of fibres, chiefly longitudinal ;
though some few have a transverse direction.
This middle coat has nothing in common with the middle coat
of the arteries. It is not elastic, and the fibres of which it is
composed are muscular, at least where the vena cava approaches
the heart
MAMMAE. 319
CHAPTER XXII.
OF THE MAMMAE OR BREASTS.
THE glands are organs destined for secreting from the blood
certain liquids, useful or indipensable for various purposes of the
animal economy. They consist of a congeries of vessels, and can-
not, therefore, be subjected to a chemical analysis with any ad-
vantage. But it may be worth while, in this and some subse-
quent chapters, to state shortly the structure of some of the most
important glands, so far as it has hitherto been ascertained by
anatomical examination.
The mammce or breasts are two round eminences placed one at
each side, on the front of the thorax, resting on the pectoral
muscles. They are fully developed in females, to whom they
belong, at the age of puberty. The mamma is a conglomerate
gland, consisting of several small lobes, each being an aggregate
of a number of lobules. Each lobule is about the size of a mil-
let-seed, oblong in shape and hollow. It consists of a mucous
lining, and an envelope of cellular tissue, in which the secreting
vessels ramify. From the lobules thus formed arise the minute
radicles of the lactiferous tubes, which receive the milk as it is
secreted. The tubes converge towards the nipple, so as to be-
come collected into a fasciculus beneath it, in which situation
they are supported by some firm cellular tissue. The number
of fasciculi varies from twelve to fifteen, and each belongs to a
particular lobe of the gland. Four, six, or eight, minute ducts
unite to form one lactiferous tube, which inclines to the areola,
where it dilates somewhat ; but at the base of the nipple it nar-
rows again, and runs in a straight course from its base to its sum-
mit, where it terminates. The tubes are lined throughout by a
mucous membrane, which permeates the whole of their extent,
and even covers the lobule. " This inner lining appears to be en-
closed in another tunic formed of cellular tissue.
From this description it appears that the mammse, if we ab-
stract the numerous vessels which cover every lobule, and which
are too minute and intricate to admit of a chemical examination,
are composed of cellular tissue lined with mucous membrane—
and therefore similar to what has already come under our review.
320 SOLID PARTS OF ANIMALS.
CHAPTER XXIII.
OF THE PANCREAS.
THE pancreas is a conglomerate gland situated behind the
stomach between the spleen and duodenum ; one extremity be-
ing in contact with the spleen and the other surrounded by the
curve of the duodenum, the left or splenic extremity is narrow
and thin ; the right is broader, and called the head of the pan-
creas. A small part of it is detached somewhat from the rest,
and called the lesser pancreas.
The granules of which this gland is composed are aggregated
into lobules, which are connected so as to form a mass of cellu-
lar tissue. It is of a pale-ash colour, about six inches long, and
one and a-half in breadth, and from half-an inch to three quar-
ters in thickness. Each granule contains within itself all the
elements of a secreting organ. In its interior is a minute cell,
being the ultimate radicle of the excretory duct, around which
is a minute vascular plexus, all of which are supported and con-
nected by cellular tissue, in which also run filaments of nerves.
Thus it appears that, if we abstract the numerous vessels and
nerves which surround every granule, the pancreas consists chief-
ly of cellular tissue. Doubtless the pancreatic duct, even to its
capillary extremities in the granules, is lined with a mucous
membrane.
CHAPTER XXIV.
OF THE LIVER.
THE liver is a conglomerate gland of a large size, destined for
the secretion of the bile ,• a liquid, the nature and properties of
which will be described in a future chapter of this volume.
The form of the liver is very irregular. Its colour is red-
dish-brown, its upper surface is smooth and convex, and is divid-
ed into two parts or lobes. Its texture is pretty firm. It is in-
vested by the peritoneum, except at the points of reflection of
LIVER.
the falx and of the lateral and coronary ligaments. Below this se-
rous coat is a thin lamella of cellular tissue, which invests the
organ in its entire extent On the surface of the liver this la-
mella is very thin, but opposite to the transverse fissure it is con-
siderably increased in quantity, encases the hepatic vessels, and
accompanies them throughout their ramifications, supporting
them in their course, and constituting the tissue in which the ca-
pillary vessels are ramified.
The liver is heavy, and weighs in an adult human subject about
four pounds. Its transverse diameter is from twelve to thirteen
inches, and its thickness from five to six inches. When torn or
divided, the exposed surface presents a granular appearance, as
if it were made up of minute grains or lobules.
From the recent examination of the liver by Mr Kiernan,*
it seems pretty clear that it consists of a great number of
small globules, each of which is made up of a reticulated plexus
of four different kinds of vessels supported by cellular tissue.
These vessels are, 1 . The minute radicles of the biliary ducts,
which divide and subdivide so as to form a mesh in the interior of
the globule. 2. The terminal branches of the vena portcs,
which convey blood to the biliary ducts, in order to secrete bile
from it. 3. The minute branches of the hepatic artery, which
convey blood into each of the globules, in order to supply the re-
quisite nourishment to the parts. 4. The minute ramifications
of the hepatic vein, which convey away the superfluous blood from
the hepatic artery and throw it into the vena portcs. Besides
these four sets of vessels the liver, doubtless, contains lymphatics,
which add to the complexity of the structure. The nerves also
of the liver serve to complete the structure of this complex or-
gan.
From the preceding statement it is evident that the liver con-
sists chiefly of a congeries of five different kinds of vessels con-
nected together by cellular tissue. It is not likely that much
light ,<could be thrown on its nature by subjecting it to a chemi-
cal analysis. We have, however, two elaborate analyses of the
liver. Braconnot analyzed the liver of an ox in 1819 ;f and
Frornherz and Gugert made a similar set of experiments upon
the human liver in 182 7 4 Vauquelin, as long ago as 1791, had
made a set of experiments on the liver of the skate (Raiabatis.)^
* Phil. Trans. 1833, p. 711. f Ann. de Chira. et de Phys. x. 189.
\ Scheweigger's Journ. 1. 81. § Ann. de Chimie, x. 193.
X
SOLID PARTS OF ANIMALS.
Vauquelin showed that the liver of the skate, which is very
large compared to the size of the other viscera, contains more
than half its weight of a liquid fixed oil. It is well-known that
a similar observation applies to the liver of the cod and of various
other fishes.
Braconnot pounded a quantity of ox -liver in a marble mortar,
mixed it with water, and passed the mixture through a piece of
cloth of a firm texture. The greatest part passed through the
cloth ; but a number of minute vessels remained behind. The
liquid thus filtered was muddy and somewhat milky. When
heated it coagulated, and a quantity of albumen collected toge-
ther at the bottom of the vessel. This precipitate was dried, re-
duced to powder, and digested in rectified oil of turpentine,
which dissolved a portion of fatty matter, to which the milky ap-
pearance of the liquid before coagulation was owing. The oil
of turpentine being distilled off, the fatty matter remaining had a
reddish-brown colour, and was viscid or almost solid. Its smell
and taste was similar to that of fried liver. It was insoluble in
water ; but soluble in alcohol of 0*833. When left long in con-
tact with caustic soda it was converted into soap. This fatty
matter, like cerebrote from the brain, contained a notable quan-
tity of phosphorus.
When alcohol was employed to separate this fatty matter from
the liver, it dissolved along with it an animal substance, which
communicated to the fatty matter the property of mixing readily
with water, and of forming a sort of emulsion, from which it
could be precipitated by infusion of nut-galls.
The albumen freed from the fatty matter by oil of turpentine,
when burnt, left phosphate of lime with a trace of iron and some
sulphate of lime. From these experiments it appears that the
coagulum by heat consisted of albumen, and a peculiar fattv mat-
ter containing phosphorus.
The liquid from which this deposit had fallen reddened litmus-
paper. When concentrated by evaporation it deposited some
additional flocks of albumen, and left, when evaporated to dry-
ness, a brownish-yellow extractive matter, which remains soft,
and cannot be completely dried. This matter resembled much
the osmazome of Thenard, but wanted its peculiar taste and fla-
vour. Potash added to it did not evolve ammonia, nor did sul-
phuric acid evolve the smell of acetic acid. It contained no al-
LIVER. 323
kaline lactate, as boiling alcohol did not extract any from it.
Indeed that reagent dissolved very little of anything from it.
The portion insoluble in alcohol being dissolved in water and
mixed with the infusion of nut-galls, let fall a prepipitate, which
Braconnot considered as albumen still remaining in it. The excess
of tannin being removed by the peroxide of tin, the remaining li-
quid contained a matter, which, being evaporated, left a substance
similar to a vegetable extract, and containing a little azote. Be-
ing dissolved in water, it became acid without putrefying.
Braconnot found ox-liver to be composed of the following con-
stituents :
Vessels and membranes, . 18 '94
Parenchyma, . . 81-06
100-00
The parenchyma contained the following substances :
Water, . 68-64
Dried albumen, . . . 20-19
Matter (containing little azote) soluble in 1
water, and little soluble in alcohol, J
Oil similar to cerebrote, . . 3-89
Chloride of potassium, . . 0*64
Ferruginous phosphate of lime, . 0-47
Acidulous salt insoluble in alcohol, , 0*10
Blood, a little.
100-00
Fromherz and Gugert analyzed the liver of a healthy young
man who had been executed. Their process was as follows :
After wiping the liver clean from blood, they cut it into small
pieces, and digested it in cold water till the liquor ceased to dis-
solve anything. The solution was slightly red, mucilaginous,
and muddy. Being separated by filtration from the albumen, it
was evaporated to the consistence of a syrup. It left an extrac-
tive matter, from which boiling alcohol extracted (besides ex-
tractive) a substance, which partially precipitated on cooling in
white flocks. This substance Fromherz and Gugert considered
as casein. But they do not mention the characters which in-
duced them to draw this conclusion. When calcined, it left some
chloride of potassium and phosphate of lime,
324 SOLID PARTS OF ANIMALS.
The alcoholic solution had a disagreeable smell, which the al-
cohol distilled from it retained. When evaporated to dry ness,
it left a dark-brown viscid mass easily soluble in water, not pre-
cipitated by acids, but by infusion of nut-galls, trisacetate of lead,
corrosive sublimate, and nitrate of silver. They considered this
substance as osmazome.
The portion from the solution in cold water which the boiling
alcohol had left undissolved had a pale-yellow colour, and was
soluble in water. They considered it as salivm mixed with a little
casein. But they do not give us the characters which induced
them to draw this conclusion.
The portion of liver which was insoluble in cold water was next
treated with boiling water, The decoction had a light-yellow
colour. It was evaporated to dryness, and the residue treated
with hot alcohol. The alcoholic solution, on cooling, deposited
some flocks of casein. It was evaporated to dryness, again dis-
solved in hot water, and the solution treated with trisacetate of
lead. The portion thus precipitated was extractive. The por-
tion not soluble in alcohol was gelatin.
The portion of liver left after the action of cold and boiling
water was treated with boiling alcohol. A transparent light-
yellow tincture was obtained, which became muddy on cooling,
and gradually let fall a yellowish-white precipitate, which was se-
parated from the liquid and digested in ether. The ether dis-
solved a portion of fatty matter, which crystallized in stars, and
which was considered as stearin. The solution contained also a
portion of elain.
The ether left a residue which possessed the following proper-
ties : It was a solid, granular, brownish-yellow mass. When
dry it became hard and brittle, and had neither taste nor smell.
It did not melt when heated to 212°. At a higher tempera-
ture it swelled up and burnt with flame, giving out a great deal
of smoke. When distilled per se it gave out a very small quan-
tity of carbonate of ammonia, probably owing to the presence
of a little foreign matter. It was quite insoluble in water, inso-
luble in cold, but pretty soluble in boiling alcohol. It was inso-
luble in ether. When heated with caustic potash, it formed a
clear solution, from which acids threw down white flocks. When
these flocks were carefully washed with water, they were soluble
in alcohol and ether, and the solution had no acid reaction.
LIVER. 3Z5
They considered it as a resinous body, to which they gave the
name of liver resin.
The alcoholic solution freed from the above described precipi-
tate, being reduced by evaporation to one- fourth of its bulk, be-
came muddy and brownish yellow, drops of oil swam upon its
surface together with larger masses, which strongly reddened
litmus-paper, and when the liquid cooled, partly crystallized in
bundles of white needles, partly remained liquid, retaining the
yellow colour. These substances were the stearic and oleic acids.
The alcoholic solution from which these two fatty acids had
separated being evaporated to dryness, left a brown substance,
soluble in water, which was considered as extractive matter.
The portion of the liver not acted on by water or alcohol was
considered by these chemists as the parenchyma of the liver, and
not subjected to farther examination.
The general result of the analysis of the human liver by From-
herz and Gugert was as follows : 100 parts of liver contain,
Water, . 61-79
Solid matter, 38-21
100-00
The solid matter consists of,
Matter soluble in water or alcohol, . 71*28
Insoluble parenchyma, . 28-72
100-00
100 parts of dry liver were found to contain 2-634 of salts.
These were chloride of potassium, phosphate of lime, phosphate
of potash, with a little carbonate of lime and traces of peroxide
of iron.
It is hardly necessary to observe, that such analyses of an or-
gan so complicated as the liver, containing at least five different
sets of vessels, all of them filled with bile, blood, or lymph, be-
sides .nerves and cellular tissue, cannot be expected to throw
much light on its nature. It is not even likely to make us ac-
quainted-with any new animal substances.
326 SOLID PARTS OF ANIMALS.
CHAPTER XXV.
OF THE KIDNEYS.
THE kidneys are the important glands which separate the urine
from the blood. In man they are two in number, situated close
to the spine on each side of the abdomen, just opposite the low-
est of the false ribs. They are almost always imbedded in a
great quantity of fat. They have a reddish-brown colour, a firm
feel, and are about the size of the fist or rather less. Their
shape resembles that of a kidney bean. Anteriorly they are co-
vered by the peritoneum, which may be easily detached from
them. When a kidney is cut across we perceive that it consists
of two different substances distinguished from each other by their
colour. These from their position are called cortical and me-
dullary.
The cortical substance, placed immediately under the investing
membrane, occupies the entire circumference of the organ, be-
ing about two lines in thickness, and sends inwards prolongations,
between which the medullary portion is placed. It has a deep-
red colour, is very easily torn, and consists almost entirely of the
capillary terminations of blood-vessels.
The medullary part consists of a series of conical masses, the
bases of which are directed towards the surface of the kidney, and
the small extremities towards its fissure. The cones are invest-
ed, except at their apex, by the cortical substance. The medul-
lary substance is more dense than the cortical, and its colour is
much lighter. As it is made up of a series of minute tubes, it
is sometimes called tubular substance.
The fissure of the kidney lodges the renal artery and vein, the
nerves and lymphatics, together with the commencement of the
excretory duct. This duct, called the ureter, expands opposite to
the fissure of the kidney into an irregular oval cavity called the
pelvis. The pelvis gives off three tubes, one to each extremity
of the organ, and the other to the middle opposite the fissure.
Each of these tubes, again, subdivides into from seven to thirteen
smaller tubes, each of which terminates in a cup-like cavity cal-
led calyx. Each calyx embraces the extremity of one or more
rounded processes called papillae ; and each papilla is the summit
KIDNEYS.
of a conical mass, whose base looks towards the circumference
of the kidney, and is, together with the sides, as it were, imbed-
ded in the cortical part of the kidney. The conical masses are
usually more numerous than the calyces, in which they terminate.
Each is composed of minute tubes, one end of which opens on
the surface of the papilla, and, therefore, pours its contents into
the investing calyx, while the other, prolonged to the base of the
cone, is there continuous with the capillary termination of the ar-
teries, from which it receives the urine the moment it is separat-
ed from the blood. It passes successively by the tubuli, calyces,
smaller tubes or infundibula, and pelvis ; whence it enters the
ureter, and is conveyed to the bladder.
The pelvis is covered by a mucous membrane, which, doubt-
less, lines also the tubuli uriniferi to their minutest termination.
It is probable also that the fibrous investment of the infundibu-
lum and calyx is prolonged so as to become continuous with the
fibres which constitute the tubuli.
From the preceding description it is obvious that the cortical
part of the kidney is little else than a congeries of vessels and
nerves connected together by cellular tissue. It is in this part
that the urine is separated from the blood. The medullary por-
tion consists of a congeries of tubes, also connected by cellular
tissue, through which the urine is conveyed to the pelvis of the
organ, whence it passes by the ureters into the bladder. It fol-
lows from this complicated structure that little light is likely to
be thrown upon the nature of these organs by subjecting them to
a chemical analysis. It would be impossible to separate the dif-
ferent kinds of vessels from each other, in order to examine them
separately, and scarcely less difficult to free them from the liquids
with which they are filled in the living animal.
Berzelius removed the serous membrane which covered the
kidneys of a horse, cut the kidney itself into small pieces, and
suspended them in cold water till they ceased to colour that li-
quid,. He then pur the kidney into a porcelain mortar, and
pounded it with a wooden pestle. By this process it was
almost -all converted into a liquid, which he filtered through
cloth. On the cloth remained a fibrous matter, which was knead-
ed in water as long as it rendered that liquid milky. The fi-
brous matter remaining after these processes constituted an ex-
ceedingly small portion of the kidney employed. This solid re-
sidue possessed the following properties :
328 SOLID PARTS OF ANIMALS.
It was white, and composed of fibre, and resembled exactly in
appearance the fibrin of the blood. When dried it became yel-
low and translucent. Ether dissolved from it a fatty matter,
which Berzelius considered as a mixture of stearin and elain.
Water softened it, and restored its original appearance. When
long boiled, it contracted and became hard. Water scarcely dis-
solved anything from it. Concentrated sulphuric acid neither
dissolved nor decomposed it, nor did it reduce it to a jelly as it
does fibrin. Nitric acid of specific gravity 1-12 dissolved it when
assisted by heat, but without decomposing it. A few colourless
flocks remained undissolved. The solution was pale-yellow, and
when saturated with ammonia became deep-yellow, but no preci-
pitate fell. It was neither precipitated by prussiate of potash nor
by infusion of nut-galls. Concentrated muriatic acid seems at
first sight not to attack the solid matter of the kidney, but it gra-
dually assumes a violet colour, and in the course of a few days
dissolves the whole of it without the assistance of heat. The so-
lution was not precipitated by prussiate of potash, nor by ammo-
nia. When saturated by ammonia and evaporated to dryness,
the residue redissolved both in water and alcohol. It was not
rendered gelatinous by concentrated acetic acid. But when di-
gested in dilute acetic acid, it was divided into two substances,
one of which dissolved in the acid, while the other remained per-
fectly insoluble.
The solution being evaporated to dryness, left a colourless and
translucent residue. It dissolved in a little cold water, and the
solution in forty-eight hours assumed the form of a jelly, which
dissolved in water, leaving a mucilaginous matter, which dissolv-
ed also when the water was heated. But it was again deposited
when the water cooled. The solution did not react as an acid,
and had neither colour, taste, nor smell. It was not precipitated
by prussiate of potash nor by acetate of lead, diacetate of lead,
nor by corrosive sublimate. But infusion of nut-galls threw it
down in large detached flocks, which did not unite into a cohe-
rent mass when heated.
Caustic ammonia decomposed the solid residue from the kid-
ney, as well as acetic acid. What the alkali had dissolved re-
mained, after the evaporation of the liquor, under the form of a
colourless mass ; and contained a matter soluble only in hot
water, in greater quantity than existed in the acetic acid solution.
KIDNEYS. 329
It contained besides a substance insoluble in boiling water.
The aqueous solution of the dried mass had no taste, and neither
reacted as an acid nor as an alkali. Even after adding to it an
acid, it was not precipitated by prussiate of potash ; but it was
thrown down by acetate of lead, corrosive sublimate, and by the
infusion of nut-galls. The portion insoluble in ammonia had
not altered its appearance. Dilute caustic potash dissolved it
with difficulty, or even not at all while cold. But, by the appli-
cation of a moderate heat, it was slowly but completely dissolved.
Acetic acid, being added in excess, precipitated the portion in-
soluble in that reagent.
From these reactions it follows that the solid portion of the
kidney is neither fibrin nor cellular tissue. It approaches near-
est to the fibrous coat of the arteries, and probably, therefore, is
little else than a congeries of blood-vessels.
The liquid of the kidney separated from the fibrous matter,
the characters of which have been just described, was muddy and
mucilaginous, and resembled milk. When heated to nearly the
boiling point it coagulated into a mass so thick that it was neces-
sary to boil it with an additional quantity of water, in order to
be able to separate the coagulum from the liquid portion. This
coagulum was dried and digested in ether, which separated a
considerable quantity of fatty matter. The residue when mois-
tened with water assumed its original appearance. It was dis-
solved in caustic potash, and acetic acid added in great excess.
The matter described above as insoluble in acetic acid was pre-
cipitated. From this it was evident that the coagulum was al-
bumen mixed with capillary blood-vessels.
The liquid separated from the coagulum was acid. When
evaporated it left a yellow extract mixed with saline crystals.
Alcohol of 0-8333 dissolved from it a yellowish acid extractive
matter, together with some common salt. And the matter re-
maining after the action of the alcohol was precisely the same
as the corresponding substance obtained from the liquid expressed
from muscle. It was mostly soluble in water, and the solution
when evaporated left a pale yellow, transparent, hard substance,
which contained phosphates. It was copiously precipitated by
lime-water. What the water had left undissolved was soft, white,
and semitransparent. It was soluble in hot water, from which it
was precipitated by tannin.
330 SOLID PARTS OF ANIMALS.
Berzelius concludes from these experiments, that the capillary
tubes of the kidneys contain a liquid very rich in albumen, and
rendered acid by the presence of a little lactic acid. But that
no fibrin exists in it. Berzelius attempted in vain to discover
the presence of urea in the liquid from the kidneys.* But the
presence of that substance has since been detected in it.
CHAPTER XXVI.
OF THE OTHER GLANDS.
BESIDES the mammae, pancreas, liver, and kidneys, there are
many other glands in the living body, destined to secret various
substances for purposes connected with the welfare of the living
animal or with the continuance of the species. It may be proper
to notice some of the most important of these glands in the pre-
sent chapter.
1. Salivary glands. — These glands are six in number ; name-
ly, two parotid, two submaxillary, and two sublingual ; one of
each on each side of the face.
The parotid gland, as the name implies, is placed near the ear.
It extends from the zygoma to the angle of the jaw and the mas-
toid process. It has a pale-ash colour, and is composed of mi-
nute granules aggregated into lobules and lobes. The external
surface of the gland is covered by the skin and partially by the
platisma muscle, and bound down by a prolongation of the cer-
vical fascia. The external carotid artery and vein passes through
its substance, and also the fascial nerve. The chemical proper-
ties of this gland have not hitherto been subjected to examination.
Nor does it seem possible to separate the glandular tissue from
the numerous vessels with which it is filled.
The submaxillary gland lies behind and beneath the ramus of
the jaw. It is separated from the parotid gland by the stylo-
maxillary membrane, where it is covered by the skin and platis-
ma, and invested with a thin membrane of cellular tissue. The
facial artery runs in a groove on its upper suface. Its excre-
tory duct, called ductus Whartoni, terminates towards the side of
* Traite de Chimie, vii. 334.
OTHER GLANDS. 331
the frenum lingua. No chemical experiments have hitherto
been made upon this glan 1.
The sublingual gland is much smaller than either of the pre-
ceding. It lies beneath the tongue close to the side of its fr>
num. Its secretion is poured into the mouth by several minute
orifices, which open beneath the tongue on each side. Nothing
is known concerning its chemical constitution.
2. The testes are two in number, and some time before birth
lie on the psoas muscle near the lower extremity of the kidneys.
Each of them is invested by a proper capsule, and receives, besides,
a partial covering from the peritoneum. About the eighth month
the testis enters the ring lying behind the process of the perito-
naeum, which goes out of the abdomen by the inguinal canal, and
in the ninth month it is found in the bottom of the scrotum.
The testis is enclosed in a firm capsule called the tunica al-
luginea. It is of a clear white colour, dense, and fibrous, and the
fibres interlace in every direction. At the posterior border it
separates into two laminae ; one of which, the external, is conti-
nued to the vas deferens. The inner surface of the albuginea is
lined by a delicate membrane formed of the ultimate ramifica-
tions of the spermatic blood-vessels, united by a little cellular
tissue, and thence called tunica vasculosa. The testis itself, be-
low these coverings, has the appearance of a soft, pulpy, dark yel-
low mass, divided into lobes. It is composed of a great number
of minute tubes, called tubuli seminiferi, which do not communi-
cate with each other. The lobes differ in size, some containing
one, and others a greater number of seminal tubes. Their shape
is somewhat conical ; the large end of which is directed towards
the circumference of the testis.
The seminal tubes are the vessels in which the semen is se-
creted. According to Monro they are about 300 in number,
the length of each is about sixteen feet, and the diameter about
3^-oth of an inch. Each of these small vessels commences by a
closed extremity, towards the inner surface of the fibrous cover-
ing of the testis, and from this point it proceeds in a zig-zag
course towards the middle of the organ. It loses its convoluted
appearance when it approaches to what is called the mediastinum
of the testis, and, passing through its fibres, opens into the next
order of vessels.
The second order of vessels is situated in the substance of the
332 SOLID PARTS OF ANIMALS.
tunica albuginea, occupying the anterior part of the process of it
called mediastinum. The blood-vessels occupy the posterior
part These vessels constitute what is called rete testis. Being
less convoluted than the tubuli, they are called vasa recta. Their
direction is backwards and upwards to reach the posterior and
upper part of the testis. The vasa recta are not so numerous?
but larger than the tubuli seminiferi^ from which they receive the
secretion ; but they are more numerous and smaller than the
vessels into which they discharge it.
These are the vasa efferentia. They are from twelve to fifteen
in number, and open separately into a single vessel of which the
epididymis is formed. This vessel or tube is very much convo-
luted, and the convolutions are united together by small fibrous
bands. It terminates in the vas deferens, which is the excretory
duct of the testis.
From the preceding description, it is evident that the testis is
composed almost entirely of tubes and blood-vessels connected
together by fibrous bands. It would be next to impossible to se-
parate the different vessels from each other, so as to be able to
examine each kind separately. And from the great minuteness
and thinness of the tubes, the different coats of which they are
composed cannot be recognized, far less separated from each
other. We need not be surprized, therefore, that no attempt
has hitherto been made to determine the chemical constitution
of the testes.
3. The lachrymal gland is placed at the upper and outer part
of the orbit, near its anterior border, corresponding with the la-
chrymal fossa in the orbital plate of the frontal bone. The
gland is convex on its upper surface. Its under surface is con-
cave, where it rests on the globe of the eye, the recti muscles
interposing. Its length is three-quarters of an inch, its breadth
half-an inch. It is divisible into two lobes, so closely connected
that the line of separation is not easily seen. When stript of the
cellular tissue it is observed to be composed of a number of gra-
nules, each forming a secreting structure, which produces the
tears. From the granules arise excretory ducts, which emerge
from the gland at its anterior border, run downwards and in-
wards close to the conjunctiva, and open in a row upon its free
surface about three lines above the upper margin of the tarsal
cartilage. These ducts are usually seven in number.
LUNGS. 333
The lachrymal gland resembles the mammary and salivary
glands and the pancreas, in this respect, that the ducts ramify
with a certain degree of regularity, the principal trunk giving
off branches laterally at certain intervals, these sending out in
the same way side branches, which in their turn afford a third
set. No attempt, so far as I know, has hitherto been made to
determine the chemical nature of the lachrymal glands.
4. Most of the other glands are so small in size that their
structure has hitherto eluded the observations of anatomists, and
the researches of chemists. The glands of the meatus auditorius
externus, which secrete the cerumen of the ear, may be mentioned
as examples ; also the sebaceous glands, those by which insensi-
ble perspiration and sweat are elaborated, and which, from recent
observations, seem to have a form somewhat resembling a cork
screw. The glands of the larynx, those that secrete mucus,
those which elaborate the gastric juice, and many other minute
glands, still remain unknown as far as their structure is concerned.
CHAPTER XXVII.
OF THE LUNGS.
THE lungs are the important organs by which respiration is
performed ; a function so necessary to life that it cannot be sus-
pended even for a few minutes without death. The lungs in
man and most quadrupeds are double, one lung being situated
on each side of the thorax. Each lung is surrounded by the
pleura, and they are separated from each other by two folds of
the pleura called the mediastinum. The lungs are connected
with the mouth and nostrils by a cartilaginous tube called the
trachea. The upper part of this air tube, being so constructed
as to constitute the organ of the voice, is named the larynx. It
consists of cartilages, ligaments, and muscles, and is lined by a
mucous membrane. Besides these there are blood-vessels and
nerves, and some glands. The cartilages are the thyroid, cri-
coid, and the epiglottis, which shuts the mouth of the larynx, by
closing down upon the rima ylottidis, in order to prevent foreign
substances from making their way into the lungs. These three
are large single cartilages constituting the throat, and very con-
334 SOLID PARTS OF ANIMALS.
spicuous on the fore part of the neck. Below them are two pairs
of small cartilages ; namely, the ary taBnoid and cuneiform car-
tilages.
The thyroid cartilage is deficient behind, its place being sup-
plied by a strong membrane. The cricoid cartilage makes a
complete circle round the tube. The trachea is a cylindrical
tube, which extends from the cricoid cartilage to the third dor-
sal vertebra. It is composed of fibro-cartilaginous rings, vary-
ing from sixteen to twenty in number, and of membranes which
connect them. The rings do not extend all round the tube ;
they are wanting behind where the trachea is contiguous to the
oasophagus. A thin elastic fibrous lamella forms the circumfe-
rence of the tube, serving to connect the cartilaginous rings, which
seem as if developed on its interior, and also to complete the cir-
cuit behind where the cartilages are wanting. Within, the
trachea is lined by a mucous membrane. Where the cartilages
are deficient, the mucous membrane is supported by some longi-
tudinal fibres, and beneath these we find a series of muscular
fibres, as in the intestinal canal.
At the third dorsal vertebra the trachea divides into two
branches called bronchii, one of which proceeds to each lung.
They are composed of the same constituents as the trachea ; but
the rings, as we go downwards, gradually lose their annular form,
and become lamellae of irregular shape, placed in different parts of
the circumference of the canal. As the tubes pass down they
subdivide into more and more branches, and at the points of
subdivision they are still somewhat annular, so much so at least,
as to keep the orifices open. So far as recognizable by our sen-
ses the minute bronchii seem to be composed of the same mate-
rials as the larger tubes ; but reduced to the greatest degree of
tenuity. These minute tubes gradually terminate in small glo-
bular vesicles, a congeries of which constitute the body of the
lungs.
The external surface of the lungs is smooth and convex. They
are divided into different lobes, and are covered by a thin serous
membrane, a continuation of the pleura. Upon the interior sur-
face of the small globular vesicles, in which the bronchiae termi-
nate, the pulmonary artery and vein ramify, so as to expose the
whole blood as it passes through the lungs to the action of the
air. These vesicles are doubtless coated by a continuation of
the mucous membrane which lines the trachea.
MEMBRANES OF THE EYE. 335
From the preceding description we see that the air-tubes
and lungs are composed of cartilage, fibrous membrane, and
mucous membrane internally, and a serous^membrane exter-
nally ; besides blood-vessels and nerves. The cartilages when
long boiled in water mostly dissolve, but the solution does
not gelatinize, however much it may be concentrated. The
serous and mucous coats are doubtless of the [same nature
as those in other parts of the body, and the same must be the
case with the arteries, veins, and nerves. But no experiments
have been made upon the fibrous membrane ; though in exter-
nal appearance it bears considerable resemblance to the fibrous
coat of the arteries. Neither has anything been ascertained re-
specting the chemical nature of the tissue which connects the in-
numerable vesicles of which the lungs are composed with one
another. The lungs themselves have a peculiar appearance, dif-
fering from that of every other part of the body, and this must be
owing to the nature of the tissue which connects these vesicles to-
gether. But it would be extremely difficult, if not impossible,
to examine that tissue separate from the various membranes and
blood-vessels with which it is so intimately connected.
CHAPTER XXVIII.
OF THE MEMBRANES OF THE EYE.
THE eye is a globular body filled internally with the aqueous
humor, the lens and the vitreous humor, and surrounded exter-
nally by three or four different membranes or coats. These are
the conjunctiva, the sclerotic coat, and the cornea ; the choroid
coat, Jacotfs membrane, and the retina.
1. The conjunctiva lines the free border and inner surface of
the eyelids, from which it is reflected on the globe of the eye, so
as to cover its anterior third. It is red and vascular on the lids,
but firm and pale on the sclerotic, and very thin and transparent
on the cornea. The chemical properties of this coat have not
been ascertained ; but it is not unlikely that it has at least a great
analogy to the cuticle.
2. The sclerotic may be considered as the true external coat
of the eye, since it covers the whole of it except the small por-
tion occupied by the cornea. It is thick, dense, and opaque.
336 SOLID PARTS OF ANIMALS.
Externally it is covered by cellular tissue and fatty matter, but
its inner side is smooth and shining, with a pearly or almost sil-
very lustre. When boiled in water it is converted into gelatin,
and is therefore similar in its nature to the skin. If we cut it
into small pieces, and digest it in water, the liquid assumes a yel-
low colour, and holds in solution an extractive matter similar
to that obtained from muscle. When the sclerotic coat thus treat-
ed is boiled in water, the jelly obtained is colourless, but contains
mixed with it numerous fragments of blood-vessels. Muriatic
acid causes the sclerotic coat to contract, and dissolves it rapidly
when raised to a boiling temperature. No gas escapes during
the solution. Acetic acid also causes it to contract, deepens the co-
lour, and when boiled on it renders it semitransparent, though
it does not dissolve it ; but if we add water, and boil it, a solu-
tion takes place which gelatinizes on cooling. Potash and prus-
siate of potash do not precipitate this solution. Hence it folio ws
that the sclerotic coat contains no fibrin.* The tendons of the
muscles of the eye being spread upon the sclerotic coat must in
some measure modify its chemical properties.
3. The cornea is a transparent membrane, which occupies the
fore-part of the eye, and is inserted into the sclerotic somewhat as
a watch-glass into a watch. It adheres firmly to the sclerotic,
so that long maceration is necessary to separate them. It is
composed of thin lamellae, and in the living eye is quite transpa-
rent ; but after death it acquires a grey colour and a semitrans-
parency, and when plunged into water it becomes opaque and
white like coagulated albumen. When boiled in water it swells
very much, then softens, and is gradually dissolved. The solu-
tion on cooling coagulates into a jelly. It is soluble in muriatic
acid. In acetic acid it swells without becoming transparent.
When we digest it in acetic acid the liquid acquires the property
of being precipitated by prussiate of potash. This shows that
the cornea besides gelatin contains also albumen.
4. The choroid coat lies immediately within the sclerotic, to
which it is attached by cellular tissue. It is soft and dark-colour-
ed, loose in its texture, and consists of two lamellae, which are
separable behind, though connected before. It is essentially vas-
cular in its structure, being composed of minute arteries and
veins united by cellular tissue. The veins, for the most part,
* Berzelius, Traite de Chimie, vii. 449.
MEMBRANES OF THE EYE. 337
occupy the external, and the arteries the internal surface of the
choroid. From this account, it is obvious that when this coat is
boiled in water, the cellular tissue will be converted into glue,
while the veins and arteries will remain undissolved.
5. Within the choroid, and next the vitreous humour, with
which it is merely in apposition, lies the retina, which is an ex-
pansion of the optic nerve. It is a soft and pulpy membrane.
In the living eye it is transparent, but a few hours after death it
becomes of a pale-white colour. According to Lassaigne, who
analyzed it, its constituents are the same as those of the medul-
lary part of the brain. But it contains scarcely iu5th of fatty
matter, one portion of which contains phosphorus, and cannot
be saponified, while the other is capable of being converted into
a soap like common fat. The retina contains
Water, . . 92-9
Albumen, . 6*25
Fat, . . . 0-85
100-0
While the optic nerve contains
Water, . . 70-36
Albumen, . 22-07
Cerebrote and fat, . 4-40
96-83
6. The pigmentum nigrum is spread upon the choroid, by the
inner membrane of which it appears to be secreted. It is easily
obtained by washing the choroid coat (freed from the retina) in
water as long as that liquid is discoloured. It remains long sus-
pended in water, and then appears of a deep-brown colour.
But it may be collected on the filter, and then constitutes a black
coherent mass. This substance was examined chemically by
Berzelius, and some years after by Leopold Gmelin.
Ber.zelius found it insoluble in water both cold and hot. It
was also insoluble in alcohol and in dilute nitric and muriatic
acids, as also in concentric acetic acid. Yet these acids assume
a shade of yellow. Dilute potash ley dissolves it with diffi-
culty, and only after long digestions. The solution is deep-yel-
low, and muriatic acid precipitates from it the colouring matter
having a light brown colour.
Y
338 SOLID PARTS OF ANIMALS.
When heated in the open air it behaves rather like a vege-
table than an animal substance. It does not melt nor swell, gives
out little smoke, but emits a disagreeable vegetable odour. When
the heat is increased it burns with flame, and leaves a greyish
ash having a shade of red. This ash dissolves with effervescence
in nitric acid, and leaves a little peroxide of iron behind.
Gmelin distilled the pigmentum nigrum and obtained an empy-
reumatic oil, carbonate of ammonia, and combustible gas, and
water. The charcoal remaining in the retort amounted to 44-6
per cent, of the pigmentum nigrum distilled. This charcoal was
difficult to incinerate. The ashes which it left consisted of chlo-
ride of calcium, carbonate and phosphate of lime, and peroxide
of iron. *A solution of chlorine made the pigmentum nigrum
much paler and dissolved about the half of it, The undissolved
portion was rendered deep-brown, and readily dissolved by potash
ley. The acids precipitated it from that solution with a brown
colour. Fuming nitric acid dissolved the pigmentum nigrum
with effervescence, and the solution had a reddish brown colour,
was bitter, and partly precipitated yellowish brown by water and
an alkali. When concentrated sulphuric acid was heated with
pigmentum nigrum sulphurous acid was given out, and a black so-
lution was formed, from which water threw down brown flocks,
which were not so easily dissolved by potash as the unaltered
pigment. Boiling muriatic acid dissolved a small quantity of
the pigment ; the solution had a brown colour. Caustic potash
dissolved it slowly and incompletely at the boiling temperature;
the solution had a reddish brown colour and disengaged ammo-
nia. Muriatic acid threw down from this solution brown flocks,
soluble in cold potash ley and in ammonia. The pigmentum
nigrum is insoluble in both fixed and volatile oils.*
In short, the properties of the pigmentum nigrum of the eye
are very similar to those of the dark matter which constitutes the
ink of the cuttle-fish.
Dr Scherer subjected it to an ultimate analysis.f He obtained,
Carbon, . 58-21
Hydrogen, . 5-92
Azote, . 13-77
Oxygen, . 22-10
100-00
* Berzelius, Traite de Chimie, vii. 451. f Ann. der Pharm. xl. 63.
SILK. 339'
Were we to construct an empirical formula it would be C4
H29 Az5 O13, showing that it has nothing in common with protein
cuticle, horn, hair, or feathers.
CHAPTER XXIX.
OF SILK.
SILK is the production of different species of caterpillars.
The Phalena bombyx is most commonly propagated for that pur-
pose ; but the Phalena atlas yields a greater quantity. A sub-
stance somewhat analogous is yielded by the greater number of
the tribe of caterpillars. It is found enclosed in two small bags,
from which it is protruded in fine threads, to serve the insect for
a covering during its chrysalis state. The silk worm is a na-
tive of China, and feeds on the leaves of the white mulberry.
That industrious nation was acquainted with the manufacture of
silk from the most remote ages ; but it was scarcely known in
Europe before the time of Augustus. Its beauty attracted the
attention of the luxurious Romans ; and after the effeminate
reign of Elagabulus it became a common article of dress. It
was brought from China at an enormous expense, manufactured
again by the Phenicians, and sold at Rome for its weight in gold.
In the reign of Justinian, (from A. D. 527 to 565), this com-
merce was interrupted by the Scythian tribes, and all attempts
to procure it failed : till two Persian monks had the address to
convey some of the eggs of the jnsect from China to Constanti-
nople, concealed in the hollow of a cane. * They were hatched
and the breed carefully propagated. This happened in the year
555 of the Christian era ; and some years after, we find that the
Greeks understood the art of procuring and manufacturing silk
as well as the orientals. Roger, King of Sicily, brought the ma-
nufacture to that island in 1 130, forcibly carrying off the weavers
from Greece, and settling them in Sicily. From that island the
art passed into Italy, and thence into France, and the revocation
of the edict of Nantz established the manufactory of silk in
Britain.
What constitutes silk exists in the body of the worm in a li-
quid state. In proportion as it exudes from the animal it har-
340 SOLID PARTS OF ANIMALS.
dens into a thread, and is then distinguished by the name of raw-
silk. There is another liquid which exudes from the silk at the
same time, and which, by solidifying, covers the thread with a kind
of varnish. The raw-silk as spun by the worm is rather brittle.
It acquires flexibility and softness by boiling it with soap and
some other processes, through which it passes before it is manu-
factured into silk cloth or ribbons or thread.
Roard in 1807 published an elaborate set of experiments on
silk.* He examined the action of water, alcohol, acids, alkalies,
and soap upon silk, and extracted from it various substances,
which he distinguished by the names of gum, colouring matter,
and wax. His paper was valuable ; but organic chemistry had
not at that time made sufficient progress to enable him to make
a satisfactory analysis of silk. The subject was taken up by
Mulder in 1836.f
To analyze silk Mulder weighed out 7 7 '2 grammes of raw
yellow silk, and 59*55 grammes of white raw-silk. Being wash-
ed in cold water that liquid was rendered yellow by the yellow
silk. It had dissolved the substance which constitutes the differ-
ence between yellow and white raw-silk. From this it would
appear that this substance is soluble in cold water.
1. Both kinds of silk were now boiled in distilled water, re-
newed repeatedly till the water ceased to be thrown down by
the infusion of nut-galls. Long boiling and much water was ne-
cessary to free the silk from every thing soluble in that liquid.
By this treatment the yellow silk was rendered lighter coloured ;
but the white was not altered. Both had acquired a softer feel.
Being dried the white silk hadjost 16*75 grammes of its weight,
and the yellow 22-2S. Or the white silk lost 28-12, and the
yellow 28-86 per cent.
The decoctions being evaporated to dry-ness over the water
bath, a brittle greenish coloured matter remained, not altered
by exposure to the atmosphere. This is the substance which
Roard distinguished by the name of gum.
2. The silk was now boiled in absolute alcohol. The yellow
silk lost its colour. The treatment was continued as long as the
alcohol acquired any colour from the yellow silk. The alcoho-
lic solutions from both silks were distilled till only four ounces
* Ann. de Chim. Ixv. 44.
f Poggendorf's Annalen, xxxvii. 594, andxl. 260.
SILK. 341
of each remained. On cooling both deposited bulky flocks,
which were separated by the filter. The liquid being still far-
ther concentrated deposited more flocks, which were added to the
former ones. These flocks from the yellow silk amounted to
1 -03 grammes, and from the white to 0-62, or 1*33 per cent, fro
the yellow, and 1-04 from the white.
3. When the alcoholic tincture ceased to deposit any more
flocks it was evaporated to dryness. That from the white silk
gave out a peculiar smell and let fall a colouring matter, which
adhered to the bottom of the vessel in stripes. The alcohol from
the yellow silk deposited a similar substance of a yellow colour.
This matter from the yellow weighed Oil grammes, and from
the white 0*15 gramme. Or that from the yellow silk was 0*14
per cent., and that from the white 0-25 per cent. The residue
from the white silk had a fine red colour.
4. The silks were now digested in repeated portions of ether,
till that liquid ceased to dissolve anything. The ether being eva-
porated, there remained a colourless residuum, weighing from
the yellow silk 0-01 gramme, and from the white 0-03 ; or 0*012
per cent, from the yellow, and 0-05 from the white.
After these processes, the yellow and white silk could not be
distinguished from each other by their appearance.
5. The silk thus treated with water, alcohol, and ether was
now digested in concentrated acetic acid. There remained un-
dissolved of the yellow silk 41-19 grammes, of the white silk
32-18 ; or of the yellow 53*3 per cent., and of the white 54-0
per cent.
6. The substance (No. 1,) which had been separated from the
silks by boiling them in water was treated with alcohol raised to
the boiling temperature. When the tinctures cooled, flocks si-
milar to those of (No. 2) separated. While under the liquid,
they were very bulky, but when the alcohol was distilled off they
lost much of their bulk, and formed a clammy substance very
small in quantity ; since that from the yellow silk weighed only
0-05 grammes, and that from the white 0-04 ; or that from the
yellow 'amounted to 0-064 per cent., and that from the white to
0-067 per cent. The residual alcohol being evaporated, left a
residue too small to be weighed.
7. This clammy substance was digested in ether. But the
ether being evaporated, left a residue too small to be weighed.
SOLID PARTS OF ANIMALS.
Mulder considers the substances thus obtained as constituting
the principles of which the silk is composed.
1. The substance extracted by boiling water, and remaining
after the residue of the decoction had been treated with alcohol
and ether, was heavier than water, friable, and destitute of taste
and smell. It did not totally dissolve in water. The solution
w as thick and opal, and adhered to the fingers ; but it did not
gelatinize on cooling. Both silks yielded to boiling water two
different substances, one of which was insoluble in boiling water,
and could be separated by the filter, the other forming a thick
adhesive solution. The first of these substances Mulder consi-
ders as albumen, the second as gelatin.
2. The flocks which were deposited from the alcoholic solution
when it cooled, he distinguishes by the name of cerin.
3. The substance which remains when the alcoholic solution,
freed from the bulky flocks, is evaporated to dryness, consists of
a fatty matter and a resinous body, and besides these two in the
residue from the yellow silk, there was a quantity of colouring
matter.
4. What the ether dissolved was also a mixture of fatty mat-
ter and resin.
5. The substance dissolved from the silk by concentrated ace-
tic acid possessed the characters of that obtained by water, and
which he had already distinguished by the name of albumen.
6. The substance remaining undissolved after the silk had been
subjected to the action of all these reagents, Mulder considered
a&Jibrin.
The following table shows the results obtained by these ana-
lyses :
Yellow Silk.
Fibrin, •; ." . 53-37
Gelatin, . 20-66
Albumen, . 24-43
Cerin, . . 1-39
Colouring matter, 0-05
Fatty matter and resin, 0-10
100-00 100-00
1. The properties of the fibrin from silk and its constitution,
according to Mulder's determination, have been given in a pre-
SILK. 343
ceding chapter of this volume. It differs so much, both in its
properties and composition fromjSfanv from blood, that it would
be better to distinguish it by a particular name.
2. The substance from silk which Mulder calls gelatin is brit-
tle, slightly yellowish, and translucent. It has neither taste nor
smell, is not altered by exposure to the air, and is specifically
heavier than water. When heated it swells up, catches fire,
burns with flame, and leaves a bulky charcoal. When this char-
coal is burnt, it leaves a white residue, consisting chiefly of car-
bonate of soda. In water it is completely soluble, but it is inso-
luble in alcohol, ether, fixed and volatile oils. The aqueous so-
lution is very glutinous, and speedily undergoes decomposition,
giving out an ammoniacal smell.
It is soluble in concentrated sulphuric acid at the common tem-
perature of the atmosphere, without undergoing any change of
colour. When heated, the solution blackens and gives out an
odour of caromel and sulphurous acid. In dilute sulphuric acid,
it dissolves when assisted by heat. If we boil the solution, satu-
rate the acid with chalk, filter and evaporate and digest the resi-
due in alcohol, that liquid, on cooling, deposites a quantity of
sugar.
Concentrated nitric acid dissolves the gelatin of silk at the or-
dinary temperature of the atmosphere. When heat is applied,
nitrous gas escapes, and oxalic acid is formed,
It dissolves in concentrated muriatic acid without change of
colour. Both common and pyrophosphoric acids dissolve it. The
solution in concentrated acetic acid, when evaporated, leaves a
thick liquid matter, from which water precipitates nothing, but
prussiate of potash throws down a beautiful green precipitate,
which is soluble in water.
It is soluble in potash, soda, and ammonia, but is precipitated
again by acids. If we add these alkalies to an acid solution, a
precipitate falls which is redissolved if we add an excess of the
alkali. It is soluble by boiling in carbonate of potash.
The aqueous solution being evaporated to the requisite con-
sistence, becomes gelatinous and adhesive. The aqueous solu-
tion is precipitated white by alcohol, infusion of nut-galls, nitrate
of mercury, diacetate of lead, chloride of tin, chlorine and bro-
mine. The chloride of gold throws down a yellow precipitate.
It is not precipitated by oxalic acid, acetate of lead, corrosive
344 SOLID PARTS OF ANIMALS. „
sublimate, nitrate of silver, nitrate of cobalt, cyanodide of mer-
cury, chloride of iron, chloride of barium, sulphate of potash,
iodide of sodium, hydriodate of ammonium, acetate of copper, tar-
tar emetic, borax, nor persulphate of iron.
It was analyzed by Mulder, who obtained
Carbon, . 47-5735
Hydrogen, . 6-0660
Azote, . 16.3210
Oxygen, . 30-0395
100-0000 *
To form an idea of its atomic weight, he precipitated it by di-
acetate of lead. The white precipitate, washed and dried at 248°,
was composed of
Gelatin, i- 56-61 or 18-26
Oxide of lead, , 43-39 or 14
100-00
If we consider the compound as a digelate, the atom of gela-
tin will be 36.52. Hence he considers .the constitution of the
gelatin from silk to be
23 atoms carbon, = 17 '25 or per cent. 47*18
17£ atoms hydrogen, = 2-1875 ... 5-98
3 J atoms azote, = 6-125 ... 16-75
11 atoms oxygen, =11-000 ... 30-09
36-5625 100-
If we compare these constituents with those of collin obtain-
•ed from skins and isinglass, as analyzed by Mulder himself, and
which have been given in a preceding chapter, it will be obvious
that the constitution is not the same. But it is possible that this
difference may arise at least in part from our ignorance of the
true atomic weight of collin. The subject requires and deserves
farther investigation.
3. The substance to which Mulder gave the name of albumen
is friable and specifically heavier than water. On a red-hot iron
it is charred with the smell of horn. It burns with flame, leav-
ing behind it a great quantity of white ash, consisting chiefly of
carbonate of soda. When distilled per se it gives out much car-
* Poggendorf s Annalen, xl. 288. .
SILK. 345
bonate of ammonia and an empyreumatic oil. A portion of it
put into concentrated sulphuric acid remained twenty-four hours
unaltered. When heated it became black, and sulphurous acid
was given out. It does not dissolve in dilute sulphuric acid even
though assisted by heat. Nor does nitric acid attack it at the
common temperature of the atmosphere. But when the albumen
is moist, concentrated nitric acid dissolves it and converts it into
oxalic acid.
Muriatic acid does not attack it at the common temperature of
the atmosphere, but dissolves it when assisted by heat ; or when
the albumen is moist. Both common and pyrophosphoric acid
blacken and decompose it. When dissolved in concentrated ace-
tic acid the albumen gives a solution having an oily appearance,
which Mulder considers as a very remarkable property. Prus-
siate of potash throws down a beautiful green precipitate not
soluble in water.
It is soluble in potash, soda, and ammonia, and is again pre-
cipitated by acids. It is insoluble in the alkaline carbonates.
Mulder subjected it to analysis and obtained,
Carbon, . 54-005
Hydrogen, . 7-270
Azote, . 15.456
Oxygen, . 23-269
100-000*
These numbers approach those obtained by Mulder from the
albumen of eggs and of blood.
4. The cerin was grey, specifically lighter than water, melted
when gently heated, and burnt with a very light flame. It was
insoluble in water, but dissolved readily in alcohol, ether, fixed
and volatile oils.
Concentrated sulphuric acid decomposes it at a high tempe-
rature. Nitric acid and muriatic acid do not attack it. When
boiled with caustic potash it is partly dissolved ; but again se-
parates when the solution cools. When alcohol is added it does
not dissolve the matter unless heat be applied. Ether does not
dissolve it. It is soluble in caustic ammonia and in concentrat-
ed acetic acid.
5. The colouring matter extracted from yellow silk was of a
* Poggendorf s Annalen, xl. 270.
346 SOLID PARTS OF ANIMALS. ^
fine red colour. When pure it is insoluble in water, but it dis-
solves in alcohol, ether, fixed and volatile oils. When treated
with chlorine or sulphurous acid, it becomes of a very light yel-
low or almost colourless.
From the observations of Reaumur, it would appear that va-
rious colouring matters are found in silk. For he mentions white,
yellow, brown, and green silk.
6. The fatty matter and resin from yellow silk are obtained
mixed with the colouring matter. When the mixture of the two
is exposed to a gentle heat, the fatty matter first melts, and then
the resin. If we agitate the mixture with a little alcohol, and
then evaporate, the resin separates in stripes, and leaves the fatty
matter alone dissolved in the alcohol.
The fatty matter and resin are soluble in alcohol, ether, fixed
and volatile oils, but not in water. They are specifically lighter
than water, and their colour is grey.
CHAPTER XXX.
OF SPIDER'S WEBS.
THE spider, as is universally known, carries in the abdomen a
peculiar liquid, which it is capable of protruding from a number
(usually five) of mammillated eminences. This liquid hardens as
soon as it is emitted, and adheres so firmly to everything with
which it comes in contact, that it cannot be separated without
rupture. This is what constitutes the web of the spider. Every
thread of the web consists of several very minute threads adher-
ing together. Spiders are oviparous, and they enclose their eggs
in a cocoon of much stronger thread than that of which their
webs are made. These cocoons may be winded like those of the
silk-worm, and M. Bon of Montpelier first showed that spider's
silk is as strong and as beautiful as that of the silk-worm. In
1710 he published the processes by which he collected this silk,
wove it and dyed it of various colours ; and he assures his read-
ers that it is in no respect inferior to the silk from the silk-worm.*
In consequence of the account given by M. Bon, Reaumur was
* Phil. Trans, xxvii. 2.
SPIDER'S WEBS. . 347
induced to try to breed spiders for the sake of their silk. But
he found that they could not be kept together ; because, bein j
all cannibals, they devoured one another, till at last, however nu-
merous at first, only a single spider was left alive in the box.
Spider's webs have long been a popular remedy for slight
wounds ; the country people being in the habit of applying them
to cuts, and apparently with success, to stop the bleeding. They
have been also administered internally as a cure for fever, and
were at one time a popular remedy, particularly in intermit-
tents.
From the great resemblance which the threads of the spider
bear to silk, we would naturally expect their composition to be
similar. But, from the experiments of M. Cadet,* the only che-
mist who has hitherto examined spider's webs, it does not appear
that this supposed analogy holds good.
When spider's webs are triturated with quicklime, they give
out a smell of ammonia. When they are digested in cold water,
that liquid assumes a reddish-brown colour, and is slightly pre-
cipitated by infusion of nut-galls. It is also precipitated by acids ;
but the precipitate is redissolved when the acid is saturated with
ammonia.
Spider's webs, cleansed as much as possible from dirt and dust,
were boiled in distilled water. The decoction smelled of mush-
rooms, and lathered when agitated. The undissolved matter was
boiled in additional water, till it gave out nothing more. These
decoctions being evaporated, let fall successive pellicles, and a
solid extract was at last obtained, amounting to nearly the half
of the spider's webs employed.
The residue insoluble in water was digested in alcohol. The
tincture obtained had an orange colour, and did not lather, water
being added to it threw down a precipitate in flocks, which as-
sumed a brown colour when dry, and amounted to about 1y0th
of the original weight of the webs. On hot coals it swelled up,
smoaked, and took fire ; and possessed properties similar to those
of a resin.
The dilute alcoholic solution being evaporated, afforded a re-
sidue slightly deliquescent, having a taste at first sweetish, but
afterwards bitter, and amounted to about three times the weight
of the resin.
* Nicholson's Jour. xi. 290.
348 SOLID PARTS OF ANIMALS.
The insoluble residue after this treatment with water and al-
cohol burned without swelling up, and gave out white fumes,
having the smell of burning wood. It was neither discoloured
by chlorine nor by sulphurous acid. It dissolved with efferves-
cence in muriatic acid, which took up two-thirds of it, and left
a black paste. From this solution ammonia threw down a small
quantity of brown matter, which, when calcined, did not lose its
colour. It was chiefly oxide of iron. The liquid to which the
ammonia had been added gave a gray precipitate with potash,
which was chiefly carbonate of lime.
When caustic potash is poured upon the residue of spider's webs
previously treated with water and alcohol, it dissolves it partially,
while a little ammonia is given out. From this solution an acid
throws down a black tasteless powder, which slightly swells when
heated, and when dried is brittle, and has the aspect of a resin.
It amounts to about one-twelfth of the exhausted spider's webs
made use of. It is partly soluble in volatile oils.
The aqueous extract of spider's webs when digested in alcohol
gave out about one-seventh of its weight. The alcohol, when
evaporated, left a brown matter, pretty deliquescent, and having
a sharp taste. It swelled considerably on burning coals, and
burnt rapidly as if it had contained nitre. It contained chloride
of calcium, and a sulphate probably of ammonia.
What remained of the aqueous extract after treatment with
alcohol was lighter coloured than before, was in powder, and had
a slightly pungent taste. On hot coals it did not swell, but left
an abundant residue. Sulphuric acid poured on it occasioned
no smell, nor did quicklime evolve ammonia.
When spider's webs were distilled per se they gave out water
slightly coloured at first, but becoming darker as the process
went on. Then a black thick oil came over with inflammable
gas and carbonic acid. The smell of ammonia was perceptible,
and the charcoal remaining amounted to about half the weight
of the spider's webs employed. This coal, when incinerated, left
two-thirds of its weight, half of which was soluble in muriatic acid,
and the residue was silica and charcoal, the muriatic acid solu-
tion being evaporated left sulphate of lime. When spider's webs
were incinerated in an open vessel, the ashes consisted of sul-
phate of lime, common salt, and carbonate of soda, a little oxide
of iron, silica, and alumina.
BLOOD. 349
Spider's webs were almost wholly soluble in six times their
weight of nitric acid, carbonic acid and deutoxide of azote
being disengaged. The solution gave sulphate of lime, and the
bitter principle of Welter.
PART II.
OF THE LIQUID PARTS OF ANIMALS.
THESE consist of blood and of the various liquid secretions. They
are numerous. But many of them cannot be procured in a state
of purity. We shall treat of them in succession in the following
chapters.
CHAPTER I.
OF BLOOD.
BLOOD is a well known fluid that circulates in the veins and
arteries of man, and the more perfect animals. The quantity in
a moderate- sized man is about 26 Ibs. avoirdupois. Its colour
is red, and it has a peculiar smell, which has been termed by
physiologists fragrant and alliacious. When examined in the
living animal by a microscope, it has the appearance of a green-
ish yellow serous liquid, in which a great number of red colour-
ed globules are floating. When drawn out of the living body
and left at rest, the globules fall to the bottom, in consequence
of their greater specific gravity, and coagulate into a firm gela-
tinous red coagulum, called the crassamentum or clot of the blood ;
while the greenish yellow serum floats above it.
One of the first persons who attempted a chemical exami-
nation of the blood was Mr Boyle in his Memoirs for the Na-
tural History of Extravasated Human Blood, published in 1684.
He showed that dried human blood is very combustible, burning
with a clear yellow flame. He found the specific gravity of the
blood of a healthy man to be 1-118. It was coagulated by al-
350 LIQUID PARTS OF ANIMALS.
cohol, nitric acid, sulphuric acid, and muriatic acid, and by a sa-
turated solution of carbonate of potash, but rendered more liquid
by ammonia. He subjected it to distillation, and obtained what
he called volatile salt of human blood, doubtless carbonate of am-
monia. He obtained also empyreumatic oils, and a caput mor-
tuum or fixed residue, very difficult to incinerate. He observ-
ed that the ashes left after the combustion of human blood had a
brick red-colour ; though he does not seem to have suspected the
presence of iron in them.
Boyle attempted to determine the proportion between the se-
rum and crassamentum of blood. But his method was so inac-
curate that it is needless to state the result. He found the speci-
fic gravity of serum 1-193. The serum was coagulated by acids
and by carbonate of potash ; but not by ammonia. It was co-
agulated also by corrosive sublimate. It seems needless to state
the results obtained by the distillation of serum as, from the in-
fant state of chemistry, when these experiments were made, they
could lead to no useful information.
In the year 1719, Dr Jurin made some experiments to deter-
mine the specific gravity of blood, which approached considera-
bly nearer the truth than those previously made by Mr Boyle.*
He showed by decisive experiments that the crassamentum was
specifically heavier than the serum, though the contrary had been
inferred from the experiments of Boyle. He found the specific
gravity of human serum in seven experiments to vary from
1-0286 to 1-0302 ; the mean of the seven being 1-0295. The
specific gravity of human blood in five trials he found to vary
from 1-051 to 1-055 ; the mean of the five being 1-0533. Dr Ju-
rin made some experiments to determine the specific gravity of
the crassamentum, and concluded it to be about 1*126. But his
method was not susceptible of accuracy.
Boerhaave's System of Chemistry, first published in 1732, con-
tains nothing more on the chemical properties of blood than had
been long before stated by Boyle.
In a note to Dr Lewis's translation of Neumann's Chemistry,
published in 1759, the fibrin of blood is first mentioned, and
the method of obtaining it detailed ; though it is not distinguish-
ed by any name.
Leewenhoek observed the globules of the blood as early as the
* Phil Trans. Vol. xxx. p. 1000 f Works of Casper Neumann, p. 551.
BLOOD. 351
year 1674 ; showed that they are heavier than serum, and rec-
koned their diameter 191¥0 of an inch.*
In the year 1747, Menghini, published a memoir in which he
proved the existence of iron in the blood, f especially in the red
globules. According to him, when preparations of iron are taken
into the stomach, the metal speedily makes its way into the blood,
when it may be detected by analysis.
Nothing or almost nothing was known respecting the saline
constituents of the blood till Rouelle published his researches on
the subject in the Journal de Medecine, for the year 1773 and
1776. He observed, that not only the serum of blood, but also
the water of dropsies, is coagulated by heat and acids like the
white of an egg. He found that these liquids gave a green co-
lour to syrup of violets, and concluded that they contain a fixed
alkali. This alkali in human blood is soda ; though he showed
by combining it with sulphuric acid and crystallizing that some
potash was also present in it. Rouelle found, likewise, some com-
mon salt, animal earth,:]: and iron in the ashes of blood. The so-
da in blood, according to him, is to the saline contents of that
liquid as 16 or 17 to 28 or 29. The animal earth constitutes
about a tenth of the whole ashes of blood. The iron, he says, has
a yellow colour, and in general is attracted by the magnet. In-
deed it was by means of the magnet that Menghini separated it.
Rouelle examined likewise the blood of the ox, the horse, the
calf, the sheep, the hog, the ass, and the goat, and found in it the
same salts as in human blood, though with some difference in
the proportions, not only in the different animals, but even in
the same species.
He made some experiments on the serum of blood, from which
apparently originated the opinion long entertained, that blood
contained gelatin as one of its constituents. He evaporated se-
rum of blood to dryness over the vapour bath. It then assumed
the appearance of glue, with this difference, that it was less solu-
ble.in water, and that it had the property of coagulating at the
boiling temperature of water. From these properties he con-
cluded' that it possessed at once the nature of gelatin and of al-
bumen.
* Phil. Trans, ix. 23, and xxxii. 341.
f De ferreorum particulorum sede in sanguine. Commentar. Bononiens., 1747,
ii. 475.
\ Afterwards shown to be phosphate of lime.
LIQUID PARTS OF ANIMALS.
Bucquet about the year 1776 * made some interesting experi-
ments on blood. He found that the crassamentum might, by
means of water, be divided into two distinct substances ; namely,
the colouring matter, which was soluble in water, and which, if
we except its red colour, possesses nearly the characters of the
serum ; and a white fibrous portion, which he distinguished by
the name of tiiejibrous part of blood, j This substance coagu-
lates when blood is allowed to cool, and then becomes insoluble
in water. When dried in a very moderate heat it becomes hard
and brittle, assumes a dirty grey colour, and contracts as parch-
ment does when exposed to the same heat
Fourcroy and Vauquelin turned their attention to animal sub-
stances at an early period of their chemical career ; and in 1790
announced the discovery of bile and gelatin in ox blood. They
affirm that, if the serum of blood mixed with the third of its
weight of water be coagulated by heat, and the albumen separat-
ed, the residual liquid, when sufficiently concentrated, assumes
the form of a jelly. J
Fourcroy assures us that blood coagulates when cooled down
to 77°, and that in the act of coagulation the thermometer rises
ll°-25, making the coagulating point 88°25.§ The serum, ac-
cording to him, coagulates at 155°*75. These and many other
observations on the blood, made about the same time (1790) by
Fourcroy, are so inaccurate that it seems unnecessary to detail
them.
Nearly about the same time a chemical examination of the
blood, with observations on some of its morbid alterations, was
published by Parmentier and Deyeux. ||
In 1797, a paper was published by Dr Wells on the colouring
matter of the blood.1F In this paper he explained the reason of
the change of colour which blood experiences by the action of
air, and showed, contrary to the opinion at that time universally
prevalent, that the colouring matter of blood is not iron, but an
organized substance of an animal nature.
* See Dictionnaire de Chirnie, par Macquer, 2d edition, article Sang des Ani-
maux.
•j- It is the substance now called fibrin. This name, I presume, was con-
trived by Fourcroy.
\ Ann. de Chim. vi. 181. § Ibid. vii. 146.
(| Jour, de Phys. 1794, p. 372, 438.
1 Phil. Trans. 1797, p. 416.
BLOOD. 353
In 1801, the Systeme des Connoissances Chimiques, by Four-
croy, was published. In the ninth volume of that work there
is a long account of the chemical properties of blood,* which?
though it contained no new investigations, yet must have been of
advantage to chemists, by exhibiting in one view all that had pre-
viously been done on the subject.
In the year 1806, Berzelius published the first volume of his
Animal Chemistry. In it he gives an account of the chemical con-
stitution of the blood, so far as it was known when he wrote,
chiefly from Fourcroy ; at least the statements are similar to those
of that chemist, and Berzelius seems to have made no experi-
ments. But the second volume of his Animal Chemistry appear-
ed in 1808. To this volume he prefixed an introduction of fifty -
nine pages, in which he gives a minute account of a laborious
set of experiments on blood, which he had made in the interval
between the publication of the two volumes. In this introduc-
tion, he gives a minute account of the chemical properties of al-
bumen, colouring matter, smdjibrin, and made the first analysis of
blood. This analysis, considering the state of our chemical know-
ledge of the subject before it appeared, is remarkably accurate, and
does great credit to the industry and sagacity of the author of it.
In the year 1812, an ingenious set of experiments on the blood
and some other animal fluids was published by Mr Brande.f He
showed that the red colour of the blood was not owing to phos-
phate of iron, as Fourcroy and Vauquelin had asserted, but to a
peculiar animal matter, as had been previously maintained by
Dr Wells. Mr Brande proved also that what had previously
been taken for gelatin in the serosity of the blood was in reality
albumen held in solution by an excess of soda. The absence of
gelatin had been previously discovered by Berzelius ; but the Ani-
mal Chemistry of that chemist having been published in the Swe-
dish language, was unknown to Mr Brande till after the publica-
tion of his memoir.
Rather before Mr Brande's paper an elaborate and remarka-
bly exact analysis of the serum of the blood was published by
Dr Marcet.J He turned his chief attention to the saline ingre-
dients of blood, and his results agreed remarkably well with those
of Berzelius upon the same subject.
* It occupies sixty pages of the English translation.
t Phil. Trans. 1812, p. 90.
| Medico- Chirurgical Transactions, ii. 370.
Z
354 LIQUID PARTS OF ANIMALS.
In the year 1831, M. Lecami published a most elaborate me-
moir on the blood. * His chemical analysis of that fluid was
more minute than that of Berzelius, and he detected several con-
stituents which had escaped the sagacity of that chemist. He
then made a comparative analysis of the blood of individuals of
different ages, sexes, and temperaments ; and he terminated his
researches by an analysis of the blood of an individual labouring
under jaundice, in order to determine whether the matter of bile
was present in it or not. In 1837, M. Lecanu, when he received
the degree of M. D. published a thesis, entitled Etudes Chimiques
sur le Sang Humain. In this thesis he gives a detailed account of
all that has been done respecting the chemical analysis of the
blood either by himself, or the many chemical writers who preceded
him. To this thesis I refer such readers as are interested in
such historical details ; and therefore terminate this historical in-
troduction here without mentioning the names of many other in-
dividuals to whom we owe important facts respecting the blood.
Many of these will be noticed in the course of the statements
which will occupy this chapter.
After this historical sketch of the progress of the chemical in-
vestigation of the blood, I proceed to lay the principal facts which
have been ascertained before the reader.
1. Blood is a liquid which circulates through living animals,
and which is destined to nourish the different parts of the animal
body, and to supply the part of the waste which is constantly
going on in it. In mammalia, birds, reptiles, fishes, and anne-
lides, it has a red colour ; while in the Crustacea, arachnides, in-
sects, and zoophytes, it is white or colourless. Hitherto chemists
have confined their examination to human blood and to the blood
of certain mammalia, especially of the ox and sheep ; the white
or colourless blood still remains unexamined.
When blood is drawn from a vein its colour is dark, when from
an artery it is scarlet. And venous blood, upon exposure to. the
air, speedily assumes a scarlet colour. Fresh-drawn blood has
a peculiar odour, which has been compared to that of garlic,
though scarcely, I think, with propriety. It has an unctuous
feel and a certain viscidity, which gradually increases as the tem-
perature sinks.
Its mean specific gravity is 1*0507. This will appear from
the following little table :
* Jour, de Pharmacie, xvii. 485 and 545.
3
BLOOD. 355
Sp. gr.
1-050 By my trial.
1-0530 Richardson.
1-0527 Haller, Phys. ii. 41.
1-0570 Berzelius, Chimie, vii. 31.
1-0510 Arterial blood. 1 -p. T -^ T i ro • XT
i /^ftrt Tr 1.1 >Dr J.Davy, Journal of Science, No. 4.
1-0490 Venous blood. J
1-0552 From temporal artery. ^ .
1-0532 Venous blood. I Scudamore, Essay on Blood,
1-0490 From jugular vein. ) p> 36'
1O560 Bullock's blood. Fourcroy, Ann. deChim. vii, 147.
1-0310 Calfs blood. Andrews, Records of Science, i. 33.
1-0530 Venous blood. Do. Ibid.
1-0507 Mean.
2. When blood is drawn from a living and healthy animal, it
is in a liquid state or nearly so. But it gradually coagulates,
and this coagulation takes place though the temperature of the
liquid be kept up, and whether it be exposed to or screened from
the action of the atmosphere. The blood of different animals,
and even of the same animal, at different times, shows a conside-
rable variation in the time that elapses after the blood is drawn
before it coagulates. This will appear from the following table,
for which we are indebted to Mr Thackrah :
Blood of the Horse coagulates in from 2 to 15 minutes.
Ox, . . 2 to 10
Dog, . £ to 3
Sheep, hog, rabbit, J to 1-J
Lamb, . . i to 1
Fowls, . i to li
Mice, ' . . in a moment.
Fish, . in a moment.*
3. When blood is viewed by a microscope while circulating
through the web of a frog's foot, or when newly drawn from a
living animal, it is found to consist of a yellow fluid, through which
a number of red globules are floating. These red globules ap-
pear to have been first noticed by Leewenhoek in the year 1674,f
He observed that they were heavier than the liquid in which they
floated. For soon after the blood is let out of the veins, the glo-
* Hunter on the Blood, p. 211. f Phil- Trans, ix. 23.
356 LIQUID PARTS OF ANIMALS.
bules gradually begin to subside to the bottom. He considered
them to be 25000 times smaller than a grain of sand.* Dr Jurin
afterwards pointed out a method of measuring their diameter,
and concluded it to amount in the globules of human blood to
T^i-5- of an inch.f They have since been measured by a variety
of micrometers. The following table, drawn up by Mr Le-
canu, will show the result of these different measurements.*
Size of globules in human blood.
Sir Everard Home, TsW^1 °f an
Eller,
Jurin,
Rudolphi,
Sprengel,
Nodgkin,
Lister,
Senac,
Tabor,
Kater,
Prevost and Dumas,
Haller,
Wollaston,
Weber,
[
^
, >
)
It has been observed that the size of the globules differs very
much in different animals. In the frog they are so large that
they are capable of being retained on a filter. The liquid which
passes through is yellow, while all the red colouring matter con-
stituting the globules remains on the filter.
Various opinions have been advanced respecting the shape of
these globules. I pass by the opinion of Leewenhoek, which seems
whimsical. Father de Torre, who made use of very small sphe-
ricles of glass to examine them, considered them as very com-
pressed flat spheroids, or rings having a perforation in the centre. §
Mr Hewson, whose microscopical observations on the blood were
first published in the Philosophical Transactions, || in order to
observe them easily, diluted the blood with fresh serum. In man,
he says, the globules of the blood are as flat as a shilling, and
* Phil. Trans, ix. p. 121. f Ibid. 1723, Vol. xxxii. p. 341.
f Etudes Chimiques sur le Sang Humain, p. 40.
f Phil. Trans. 1765, p. 246. || Ibid. 773, p. 303.
BLOOD. 357
appear to have a dark spot in the middle. In the frog the glo-
bules are six times as large as in man. In the blood of that ani-
mal it is easy, he says, to show that the globule is not perforated
as Torre supposed ; but that the dark spot is a little solid body,
which is contained in the middle of a vesicle. Hence, he calls
the globules red vesicles, each, according to him, being a flat ve-
sicle, with a small solid sphere in its centre. When a little wa-
ter is added to the blood, the vesicles swell and become round,
and if the glass plate on which they are lying be placed oblique-
ly, they may be seen running down it, while the little central so-
lid may be seen falling from side to side like a pea in a bladder.
Water gradually dissolves the red vesicles, leaving the central
solid undissolved, But if a little salt be added to the water, the
vesicles become flat, and do not dissolve.
Hewson conceived that the use of the thymus and lymphatic
glands was to form the central solids, and that the vesicles which
surround them are formed in the spleen.
But this hypothesis respecting the formation of the red glo-
bules has not been confirmed by later observers. Nor has
Hewson's account of the shape and structure of these globules been
admitted as exact. They seem to be flat ellipsoids, and the notion
of their being.vesicles containing a central nucleus has not been
adopted.
In the blood of the frog, where the globules are six times as
large as in human blood, the globules may be separated from
the serum by the filter. In all red-blooded animals the globules
may, by careful washing, be deprived of their colour. The red
colouring matter dissolves in the water, but the globules re-
main undissolved, and assume a whitish colour.*
Lecanu has shown by experiments seemingly decisive, that the
globules of blood consist at least of three distinct substances,
namely, hematosin, albumen, and fibrin, and that the weight of
hematosin does not exceed ^h Pai*t of that of the globule. •(•
The fibrin, in his opinion, constitutes the outer surface of the glo-
bules, and envelopes a compound of hematosin and albumen,
which has been generally taken for the colouring matter of blood.
* Mr Gulliver has examined and described the globules in a great number of
animals. His valuable results may be seen in the Philosophical Magazine, (3d
series) xvi. 23, 105, 195. They are too long and too little connected with che-
mistry to find a place here.
t Etudes Chimiques sur le Sang Humain, p, 48.
358 LIQUID PARTS OF ANIMALS.
I. The number of constituents discovered in blood, not reckon-
ing water, which constitutes a considerable portion of it, amount
at least to 22. The following table exhibits the names of these
substances :
1. Albumen. 12. Common salt.
2. Hematosin. 13. Chloride of potassium.
3. Yellow colouring matter. 14. Sal-ammoniac.
4. Fibrin. 15. Sulphate of potash.
5. Extractive matter. 16. Carbonate of soda.*
6. Serolin. 17. Carbonate of lime.
7. Cholesterin. 18. Carbonate of magnesia.
8. Cerebrote. 19. Phosphate of soda.
9. Iron. 20. Phosphate of lime.
10. A volatile fatty acid salt. 21. Phosphate of magnesia.
II. Soap of margaric and 22, Lactate of soda.
oleic acids.
Let us take a view of these different substances in succession.
1. Albumen. — It has been already observed, that when heal-
thy blood is drawn from an animal and left at rest, it gradually
separates into two portions ; namely, a gelatinous looking sub-
stance, containing all the red globules, and called the crassamen-
tum or clot, and a liquid portion of a greenish yellow colour,
which floats on the surface, called the serum.
It was first observed by Dr Harvey, that when the serum is
heated it coagulates and becomes as firm as the white of an egg,
though not so white, f The point of coagulation, as measured by
my thermometer, is 159.° It had been long known that the
white of an egg coagulates when heated to the same point.
Rouelle and Bouquet about the year 1776, first compared serum
of blood and white of egg together, and concluded that both con-
tained a similar substance, which from the white of egg, which con-
tains it in the state of greatest purity, has got the name of albumen.
The albumen of eggs was examined with some care by Neu-
mann, who ascertained its property of being coagulated by heat,
alcohol, and acids, found that in a gentle heat it might be evapo-
rated to dryness, constituting a yellowish translucent substance
resembling amber in appearance, and still capable of dissolving
* Dr Davy is of opinion that the soda in blood is in the state of sesquicar-
bonate. See Phil. Trans. 1838, p. 291.
| De Generatione Auim. p. 161.
BLOOD. 359
in cold water. When thus dried 100 parts of albumen were re-
duced to 25 parts.
Albumen combines both with acids and bases. It is pre-
cipitated in grey flocks by tannin.
2. Fibrin. — When the crassamentum of blood is put into a
linen cloth, and carefully washed till all the red colouring matter
is removed, the substance which remains has received the name
ofjibrin. When moist it is white, soft, and composed of long
fibres or threads. Hence the reason of the name, which seems
to have been first imposed by Fourcroy and Vauquelin.
It was long the opinion of physiologists, that the globules of
the blood consisted of a nucleus of fibrin inclosed in a vesicle of
colouring matter. Hence was inferred the reason why it exists
in the crassamentum. But later observations have considerably
modified this opinion. Piorry and Scelles de Mondezert have
remarked, that if we cautiously and rapidly remove the serum
which floats upon the crassamentum, we will frequently find it
become opaline and muddy, and finally, it is covered with a skin
analogous if not identical with fibrin.* According to Muller, if
we amputate the thigh of a frog, and mixing the blood with an
equal quantity of water, holding sugar in solution, throw the
whole upon a moistened filter, the red globules, which are very
large in that animal, are retained upon the filter, while a colour-
less and clear liquid passes through. In this liquid a coagulum
of fibrin speedily appears.
From these facts there seems no reason to doubt that the fi-
brin exists in the serum as well as albumen ; and that the glo-
bules consist of a red colouring matter, and a white insoluble
substance, the nature of which has not been ascertained ; though
in all probability it is analogous to coagulated albumen or fibrin.
Indeed, Lecanu has shown by numerous experiments, that the
globules consist essentially of three distinct substances, namely,
hematosin, albumen, and fibrin. f
Fibrin may be procured likewise from the muscles of animals.
Mr Hatchett cut a quantity of lean beef into small pieces, and
macerated it in water for fifteen days, changing the water every
day, and subjecting the beef to pressure at the same time, in or-
der to squeeze out the water. The ushreds of muscle, which
amounted to about 3 Ibs., were now boiled for five hours every
* Lecanu, p. 43. f Ibid. p. 50.
360 LIQUID PARTS OF ANIMALS.
day for three weeks, in six quarts of fresh water, which was regu-
larly changed every day. The fibrous part was now pressed and
dried by the heat of a water bath. In this state it possessed
the characters of almost pure fibrin.*
It is extremely difficult to free the fibrin of blood completely
from the hematosin. The easiest way is to stir new drawn ox
blood rapidly with a stick. The fibrin adheres to the stick. Let
it be taken off and well-washed in cold water till that liquid ceas-
es to be coloured. Then steep it in cold water for twenty-four
hours, washing it frequently and carefully during that time.
Finally, let it be digested in alcohol, or still better in ether, to se-
parate a fatty matter which it still contains.
3. Hematosin. — This name was given by M. Chevreul to the co-
louring matter of blood, which Dr Wells, as early as 1797, show-
ed to be an animal substance of a peculiar nature. Vauquelin
and Brande proposed processes for obtaining it in an isolated
state. But they did not succeed in freeing it from the albumen
with which it is always mixed in the crassamentum. The pro-
cesses of Berzelius and Engelhart enabled chemists to obtain
hematosin in a state of tolerable purity ; but, as it was coagulat-
ed and consequently insoluble in water, it was not possible to de-
termine its characters with the requisite precision.
4. Cholesterin. — This is the name by which the white crys-
talline matter constituting the principal part of human biliary
calculi has been distinguished. Its existence in the serum of
blood was discovered in 1833, by M. Felix Boudetf His dis-
covery was confirmed by Lecanu in 18374 It was extracted in
the following manner : 1000 grammes of human serum were
dried over the vapour bath, the dry residue was pulverized, passed
through a sieve, and treated three times with ether in Chevreul's
digester. The etherial liquids were mixed together, and three-
fourths of them were distilled off. The residue was evaporated
to dryness over the vapour bath. A considerable quantity of
matter remained, which had a fatty aspect, a disagreeable smell,
and the consistence of honey.
When digested in alcohol a portion was dissolved, which had
a yellow colour and reacted as an acid, When left to spontane-
ous evaporation it deposited a pearly matter, which possessed the
characters of cholesterin.
* Phil. Trans. 1800, p. 327. f Jour, de Pharm. xix. 294.
| Etudes Chimiques sur le Sang Humain, p. 46.
BLOOD. 361
5. Oleic and Margaric acids. — Boudet seems first to have no-
ticed these acids in the serum of blood, and to have extracted
them in the state of a soap.* They were afterwards obtained
by Lecanu. When the yellow alcoholic liquid, described in the
last paragraph, from which the cholesterin has precipitated by
spontaneous evaporation, is evaporated over the vapour bath,
there remans a yellowish transparent matter, evidently a mixture
of an oily, yellow, and colourless solid matter.
The yellow oily matter was liquid, very soluble in cold alco-
hol, which it rendered acid ; very soluble in alkaline solutions,
and not capable of being distilled over with water. It was oleic
acid.
The colourless solid substance had a pearly lustre, was very
little soluble in cold alcohol ; but very soluble in cold ether.
It was very soluble in boiling alcohol, which it rendered acid,Band
was deposited when the liquid cooled in pearl-coloured plates.
It melted between 131° and 136°, and when calcined left no al-
kaline residue. It was margaric acid.
6. Serolin. — This substance was detected in the serum of blood
by M. Boudet in 1833.f He obtained it by setting aside a hot
alcoholic decoction of dried serum. As the alcohol cooled, a
white matter, having a slightly pearly lustre, was deposited. It
was the serolin.
7. Cerebrate. — This substance was first discovered in the se-
rum of blood by Chevreul. The discovery was confirmed by
the subsequent researches of Boudet. It was obtained by this
last chemist in the following way :
Serum of blood, dried and deprived of every thing which boil-
ing water is capable of extracting, was reduced to powder and
treated with boiling alcohol. The alcoholic solution on cooling
deposited serolin. The filtered liquid was distilled till three-
fourths of the alcohol passed over. The residue became muddy ;
but nothing was deposited. Being cautiously evaporated to dry-
ness, a yellowish brown matter remained, of the consistence of
turpentine, which formed an emulsion with cold water. Its taste
was acrid and analogous to the fatty matter of the brain. When
triturated with cold alcohol of 0-8428, till nothing more would
dissolve the substance that remained possessed the characters of
the fatty matter of the brain.
* Journ. de Pharmacie, xix. 264. f Ibid. xix. 299.
362
LIQUID PARTS OF ANIMAL*.
8. Urea. — It has been long known that urea constitutes one
of the characteristic constituents of urine. Now urine is sepa-
rated from the blood by the kidneys, and it has been the general
opinion of physiologists, that the constituents of urine are not
merely separated from the blood by the kidneys, but that they
are actually generated from the blood by these organs. But
the experiments of Prevost and Dumas have demonstrated the
contrary of this. It follows from their experiments that urea
exists in blood ready formed ; but, as the kidneys are constantly
separating it from that liquid, the quantity of it, when the animal
is in a state of health, is always so small that it cannot be de-
tected in blood by the most delicate tests which we have it in our
power ta apply. Prevost and Dumas separated both the kid-
neys from dogs, cats, and rabbits, and examined the blood of
these animals four or five days after the excision. They always
discovered in this blood a notable quantity of urea.* As urea
exists in urine combined with lactic acid, there can be little
doubt that this is the case also with the urea in the blood.
9. The preceding eight substances are the only ones (the salts
excepted) which have been hitherto shown to exist constantly in
healthy blood. A variety of other bodies have been noticed by
chemists, but they are omitted here, because their existence or
their characters have not been sufficiently constated. Thus Four-
croy and Vauquelin,-f- Proust,! and Orfila,§ announced the ex-
istence of bile in blood. Deyeux and Parmentier stated the ex-
istence of gelatin as a constant constituent of blood. || Deyeux
suggested the existence of a peculiar matter in the globules of
blood, to which he applied the name of tomellin, and to which he
ascribed the homogeneous concretion of the entire blood in the
preparation of puddings.! Denis makes osmazome one of the
constituents of blood.** All these and several other substances
noticed by Lecanu, as cruorin, erythrogen, have been omitted, be-
cause their existence in blood has not been demonstrated, nor
have their properties been sufficiently determined.
10. Soda. — -The serum of blood renders cudbear paper purple,
and therefore contains an alkali. This alkali in human blood is
* Ann. de Chim. et de Phys. xxiii. 90. f Ibid. vi. 181, vii. 154.
\ Ann. de Chim. xxxvi. 276. § Elemens de Chiraie, ii. 313.
|| Jour, de Phys. xliv. 438.
1 Syst. de Conn. Chim. ix. 210. English translation.
** Recherch. Experim, sur le Sang Hum. p. 107.
BLOOD. 363
soda. Whether it be the same alkali that exists free in the se-
rum of the blood of the inferior animals, or whether potash may
not replace it at least in some, has not yet been determined.
Most chemists affirm that the soda in human blood is in the state
of carbonate. But I have not been able to satisfy myself that
this is the case. It is more probable that at least a portion of it
is united to lactic acid. It has been satisfactorily proved that
albumen is capable of combining with alkaline bodies, and that
this combination increases its solubility. It is most reasonable
to admit that the soda in human blood, not in combination with
acids, is united to the albumen, and that to this combination the
solubility of the albumen in the serum is at least partly owing.
1 ] . It has been already stated that the first person who turn-
ed his attention to the salts in blood was Rouelle. He detected
common salt, phosphate of lime, and some potash, as well as soda.
Dr Marcet made]a careful analysis of the serum of blood about
the year 1812, and extracted from 1000 parts of that liquid,
Chlorides of potassium and sodium, . 6'60
Carbonate of soda, . . . 1 '65
Sulphate of potash, . . . 0-35
Phosphate of lime with trace of magnesia, 0-60
Mucous extractive matter,
Albumen, ....
Water, ....
1000-0*
Berzelius had analyzed the serum of blood in 1808,f though
his results were not known in this country till he came to Lon-
don in 1812. He obtained from 1000 parts of serum of human
blood,
Common salt, . . . 6
Lactate of soda, . . • .. 4
Soda, phosphate of soda with some albumen, 4.1
14-1
Albumen, . . 80
Water, . . . 905-9
1000.
* Medico- Chirurgical Transactions, ii. 370. f Djurkemien, ii. 55.
364 LIQUID PARTS OF ANIMALS.
The mucoso-extractive matter of Marcet, and the lactate of
soda of Berzelius, are two different names given to the same sub-
stance.
The crassamentum yielded when incinerated an ash, which,
when 1000 parts were burnt, amounted to 15. Of this ash,
water dissolved three parts, consisting partly of carbonate of so-
da, and partly of phosphate of soda. The undissolved portion
consisted of,
Peroxide of iron, . . 5
Perphosphate of iron, . 1
Bonearth, . . 1
Pure lime, ... 2
Carbonic acid, . 1
10
The following table exhibits the salts which exist in human
blood, according to the latest statements of Lecanu ; though
he has nowhere, so far as I have observed, given a detail of the
method by which they were detected.
1. Common salt. 8. Phosphate of soda.
2. Chloride of potassium. 9. Phosphate of lime.
3. Sal-ammoniac. 10. Phosphate of magnesia.
4. Sulphate of potash. 11. Lactate of soda.
5. Carbonate of soda. 12. Margarate and oleate of soda.
6. Carbonate of lime. 13. A volatile fatty acid salt.
7. Carbonate of magnesia.
12. Having now stated the different substances which exist in
blood, with the exception of the gaseous bodies which have been
detected by various chemists, it may be proper, before proceed-
ing farther, to notice these gases as shortly as possible. The
gases found in blood are oxygen, azotic and carbonic acid.
It was long ago shown by Hoffmann and Steevens that, when
venous blood is kept in the vacuum of an air-pump, carbonic
acid gas is given out. But, as succeeding experimenters did not
succeed on their trials, it was long generally admitted that ve-
nous blood contained no sensible quantity of carbonic acid gas,
and hence it was inferred that the carbonic acid gas in expired
air was formed in the lungs. The experiments of Magnus have
at last proved in the clearest manner that blood, both venous and
arterial, contains carbonic acid, oxygen, and azotic gases. *
* Ann. de Chim. et de Phys, Ixv. 169.
BLOOD.
365
When a current of hydrogen gas, azotic gas, or even oxygen
gas is passed through venous blood, it gives out carbonic acid to
the amount at least of one-fifth of the volume of the blood. When
venous or arterial blood is kept in the vacuum of an air-pump,
it gives out gaseous matter, which was collected and analyzed
by Magnus. The following table shows the results obtained : —
Volume. Vol. of
gases.
9-8
Arterial blood of a horse, 125
Composition.
5*4 carbonic acid.
Venous blood of ditto, four )
days after the arterial, j
Same blood,
Arterial blood of an old \
horse, /
Same blood,
Venous blood of same
horse three days after,
Arterial blood of a calf,
Same blood,
Venous blood of ditto, four 1
days after, /
Same blood,
205 12-2
195 14-2
1-9 oxygen gas.
2*5 azotic gas.
8*8 carbonic acid.
2*3 oxygen.
1-1 azote.
1OO carbonic acid.
2*5 oxygen.
1*7 azote.
130 16-3 10-7 carbonic acid.
122 10-2
4*1 oxygen.
1*5 azote.
7'0 carbonic acid.
2 -2 oxygen.
1*0 azote.
170 18-9 12-4 carbonic acid.
123 14-5
108 12-6
2-5 oxygen.
4*0 azote.
9*4 carbonic acid.
3 -5 oxygen.
1*6 azote.
7*0 carbonic acid.
3-0 oxygen.
2*6 azote.
153 13-3 10-2 carbonic acid.
1-8 oxygen.
1*3 azote.
140 7 '7 6'1 carbonic acid.
1-0 oxygen.
0-6 azote.
366 LIQUID PARTS OF ANIMALS.
Dr Davy has found that fresh blood, when agitated with oxy-
gen gas or common air, absorbs a little oxygen gas, while the
thermometer rises one or two degrees, without giving out any
carbonic acid gas. He could not find that blood gave out car-
bonic acid gas when agitated with other gases ; but it absorbed
more than its own volume of carbonic acid. *
It is not easy to draw any inference from these contradictory
experiments.
II. PROPORTION OF THE CONSTITUENTS OF BLOOD.
Having described the different substances which enter into
the constitution of blood, let us now endeavour to state the va-
rying proportions of each in different circumstances.
1. When blood is left at rest it divides into two portions, the
serum and crassamentum. The proportion between these two
differs greatly under different circumstances.
(1.) There is a considerable diversity in the specific gravity of
serum, as will appear from the following table :
Sp. gravity.
1-027 to 1-029 Berzelius.
1-025 Marcet, Med.-Chir. Trans, iii. 363.
1-0287 By my trials.
1-0262 Richardson.
1-0264 Arterial. \ ^ de Sciences Natur_ g
1-0257 Venous. J
1-047 to 1-050 Dr Davy, Phil. Trans. 1814, p. 591.
1-020 of a calf after three bleedings. 1 Andrews, Records of
1-017 do. after four bleedings. / Science, i. 53.
If we leave out the determinations of Dr Andrews, because the
blood was not in a normal state, the mean specific gravity of se-
rum is 1-0296. And if we leave out the determination of Dr
Davy, which deviates too far from the rest, the mean specific gra-
vity of serum will be 1-0265.
(2.) The mean specific gravity of the crassamentum, accord-
ing to Dr Jurin, is l-245.f
(3.) The crassamentum cannot be freed completely from the
serum. It consists essentially of the globules of the blood ; and
these globules, according to the experiments of Lecanu, are com-
posed of fibrin, hematosin, and albumen.
(4.) The following table exhibits the proportions between the
- Phil. Trans. 1834, p. 283. f Haller's Physiology, ii. 41.
BLOOD.
367
water, salts, &c., albumen of serum and globules in the blood of
individuals of different ages. The table was drawn up by Le-
canu from his own experiments.*
Water.
Salts, &c.
Albumen
of Serum.
Age of the
Globules. Individual.
780-210
14-000
72-970
132-820
45
790-900
8-870
71-560
128-670
26
782-271
10-349
66-090
141-290
36
783-890
9-770
67-890
148-450
38
805-263
12-120
65-123
117-484
48
801-871
11-100
65-389
121-640
62
785-881
10-200
64-790
139-129
32
778-625
11-541
62-949
146-885
26
788-323
8-928
71-081
131-688
30
795-870
10-010
* 78-120
115-850
34
805-263
14-000
78-120
148-450
Maximu
778-625
8-870
67-890
115-850
Minimal
26-638
5-130
10-230
32-600
Differen
789-3204
10-6888
68.059
132-4906
Mean of
(5.) The preceding table will give the reader an idea of the
various proportions between the serum and crassamentum of blood
in different individuals. Let us now see what is the constitution
of the serum according to the various analyses that have been
made.
Dr Marcet found the constituents of serum as follows :
Water, .... 900
Albumen, . . . . 86-8
Chlorides of potassium and sodium, 6*60
Mucous extractive matter, . 4-00
Carbonate of soda, . . 1 *65
Sulphate of potash, . . 0-35
Earthy phosphates, . .0*60
13-2
1000
Berzelius obtained,
Water,
Albumen,
Alkaline chlorides,
Lactate of soda, &c.
Carbonate of soda,
Phosphate of soda,
Animal matter,
905
80
14
999
* Etudes Chimiques sur le Sang Humain, p. 62.
368 LIQUID PARTS OF ANIMALS.
Prevost and Dumas obtained,
Water, . . 900
Albumen and salts, . 100
1000
Lassaigne obtained,
Water, . . 910
Albumen and salts, . 90
1000
Lecanu obtained,
1st Analysis. 2d Analysis.
Water, . . . 906- 901-
Albumen, . ': . . 78- 81-2
Extractive, . . . 3-79 4-60
Fatty bodies, . r* R . . 2 -20 3-40
Alkaline chlorides, . . 6-00 5-52
Alkaline carbonate, phosphate, and )
sulphate, . . /
Carbonates of lime and magnesia, 0-91 0-87
Phosphates of lime and magnesia.
998-90 998-59
M. Lecanu made other experiments. He dried a given weight
of serum, digested it in alcohol and water, and ascertained by
evaporation the weight of the substances extracted by these ve-
hicles. His results were as follows :
Water 909-330 I Maximum> 920*546
/ater> 1 Minimum, 900
f Maximum, 88-520
Albumen, . 78-013 1 w • Ot7 nork
\ Minimum, 67-980
Extractive salts 1 19fi/rfi r Maximum, 17-000
Fatty matters, J b \ Minimum, 10-160
(6.) The crassamentum cannot perhaps be completely freed
from serum ; but, by washing the globules in a saturated solution
of sulphate of soda, they may be made tolerably pure. In that
case we estimate the constitution of the globules according to the
determination of Lecanu as follows :
BLOOD.
369
Fibrin,
Hematosin,
Albumen,
2-253
1-735
96-012
100-
The following table exhibits the constituents of human blood
as determined by Mr Richardson in my laboratory. His colour-
ing matter was obviously the globules of the blood, consisting of
fibrin, hematosin, and albumen, in the proportions just stated :
Specific gravity of the blood, 1-053.
Water, .... 785-890
Fibrin, . . . 2' 120
Colouring matter, . . . 134-780
Albumen, . . . 63-008
Cholesterin and serolin, . . 1-357
Oily fatty matter, . . 0-808
Extract and lactic acid, . . 1-831
Albuminate of soda, . . 0-956
Alkaline chlorides, . . . 5-341
Alkaline carbonate, sulphate, and phosphate, 2-110
Subsesquiphosphate of iron, . . 1-021
Subsesquiphosphate of lime, . 0-056
Phosphate of magnesia, . . 0-193
Peroxide of iron, . . 0*203
Carbonate of lime, \
Carbonate of magnesia, /
100-000
The following curious table, drawn up by M. Denis from his
own experiments, and exhibiting the constitution of blood at dif-
ferent ages, deserves to be inserted.*
At birth,
From birth to 10,
10 to 20,
20 to 30,
30 to 40,
40 to 50,
50 to 60,
60 to 70,
Vater. Fibrin. Albumen. Globules. Salts, &c.
Total.
86
0-9
8-1
3-4
•6
100
82-5
1-5
7-7
6-8
•5
100
79
1-4
6
12-1
•5
100
76
1-0
5-7
15-7
•6
100
76
1-2
6
15-2
•6
100
76
1-2
6-7
14-6
•5
100
78
1-2
7
12-5
•3
100
79-5
0-9
7
11-3 1-5
100
* Jour, de Physiol. ix. 218.
Aa
$70 LIQUID PARTS OF ANIMALS.
Many experiments have been made to determine whether
any difference exists between the blood o/ males and females.
From the trials of Lecami it follows that the proportion of albu-
men in both is sensibly the same.
In man. In woman.
Maximum, . 78-270 74-740
Minimum, . 57-890 59-159
Mean, . 68-080 66-9495
The proportion of globules is greater in the blood of men than
in that of women.
In man. In woman.
Maximum, . 148-450 129-999
Minimum, .. 115-850 68-349
Mean, . 132-150 99-1695
The proportion of water is greater in the blood of women than
of men.
In man. In woman.
Maximum, . 805.263 853-135
Minimum, .. 778.625 790-394
Mean, . 791*944 821-7645
With respect to temperament, the blood contains more water
in persons of a lymphatic than of a sanguine temperament ; the
proportion of albumen is nearly the same in both, but the glo-
bules are more numerous in the blood of sanguine than of lym-
phatic individuals.
When blood is repeatedly drawn from the same individual
the proportion of water increases, while that of the globules di-
minishes after each bleeding. This was ascertained by M. Le-
canu* and by Dr Andrews, f
In the case of uterine hemorrhagy the proportion of water is
greatly augmented, while that of the globules, and even of
the albumen is much diminished.^ When the nourishment is
diminished, the water in the blood increases, while the globules
diminish. The albumen is not much altered in quantity.
Many experiments have been made to ascertain whether any
difference exists between venous and arterial blood. The follow-
ing table exhibits the specific gravity of each as determined by
different experimenters :
* Jour, de Pharmacie, xvii. 557. f Records of General Science, i. 31.
\ Lecanu, Jour, de Pharmacie. Ibid.
BLOOD. 371
Arterial. Venous.
1-049 1-051 John Davy on calves, oxen, sheep, dogs.
1-053 1-058 Scudamore. Human blood.
1-0433 1-0487 -j
1 -0398 1 -0429 V Letellier. Human blood.
1-0455 1-0531 )
1-0461 1-0507 Mean.
Arterial blood coagulates and putrefies more rapidly than ve-
nous blood.
The crassamentum from arterial blood is more bulky and
firm than that from venous blood., The amount of the differ-
ence will be seen in the following table :
Crassamentum. Serum.
In the cat, . 1163 . 8837 in venous blood.
1184 . 8816 in arterial.
In a sheep, . 861 . 9131 in venous.
935 . 9065 in arterial.
In a dog, . 970 . 9300 in venous.
995 . 9005 in arterial.
From the experiments of Prevost and Dumas, it appears that
the proportion of fixed matters to water is greater in arterial
than in venous blood. This will be seen by the following ta-
ble:
Arterial blood. Venous blood.
Fixed matters. Water. Fixed bodies. Water.
In the sheep, . 17-07 82-93 16-36 83-04
In the cat, . 17-65 82-35 17-41 82-59
In the cat, . 19-62 79-38 19-08 80-92
Mean, 18-11 81-89 17'62 82-38
The analyses of Lecanu agree with those of Prevost and Du-
mas ; but Denis made four analyses of the arterial and venous
blood of a man, of a woman, and of a dog, and found the pro-
portions of water and fixed matters the very same, both in venous
and arterial blood.
The albumen, salts, and fatty matters, as far as can be infer-
red from a considerable number of comparative experiments, ex-
ist in the very same proportions in arterial and venous blood.
Many other comparative experiments on arterial and venous
LIQUID FARTS OF ANIMALS.
blood have been made. But the results obtained are so incon-
sistent with each other that no satisfactory conclusions can be
deduced from them. The following may be considered as the
differences between arterial and venous blood, which seem to be
pretty satisfactorily determined.
1. The colour of arterial blood is scarlet, that of venous brown-
ish red and much darker.
2. Arterial blood coagulates more rapidly than venous blood.
3. The crassamentum from arterial blood is more bulky and
firmer than that from venous blood.
4. Arterial blood contains less water than venous blood.
5. Arterial blood contains more globules and more fibrin
than venous blood.
6. The albumen, fatty matters, and salts, are the same in both.
7. Probably arterial blood contains most oxygen gas, and ve-
nous blood most carbonic acid gas.
8. According to the analysis of MM. Macaireand Marcet
Junior, arterial blood contains more oxygen than venous blood,
while venous blood contains more carbon than arterial blood.
The result of their analyses was as follows :*
Arterial. Venous.
Carbon, ...>.:. 50-2 ,_/._. 5^'7
Hydrogen, 6-6 $>•*$ 6-4
Azote, .' 16-2 . 16-2
Oxygen, . 36-3 • . 217
99-3 100-0
9. The specific gravity of arterial blood is rather higher than
that of venous blood.
Would it be safe to infer from these facts, that the part of the
blood chiefly employed in nourishing the living body is the glo-
bules, and that the diminution of these globules during the cir-
culation is made up again while the blood is passing through
the lungs ? The chyle contains globules ; but they are white, and
it appears from the analyses of Macaire and Marcet that the
quantity of azote is much greater in blood than in chyle.
Dr Denis made a comparative analysis of the blood drawn
from a vein and from the capillary vessels by means of cupping-
glasses. But no appreciable difference could be discovered.
* Mem. de la Societe Phys. et d'Hist. Nat de Genev- v. 22a
BLOOD. 373
Prevost and Dumas analyzed the blood of the vena portae, and
obtained the following results.*
Water, . 801-4
Albumen and salts, 84-4
Globules, . 114-2
1000-0
The globules, as might be expected, are less and the water
more than in venous blood ; doubtless because a considerable
portion of the globules in the arterial blood has been employed
in nourishing the abdominal viscera from which the vena portce
proceeds.
According to Denis, the blood of the placenta contains less
water and more globules than the venous blood of the same wo-
man. The albumen, fatty matters, and salts are sensibly the
same. This blood has the smell of the liquor of the amnios, and
a decidedly brownish red colour. The blood of the foetus is
quite similar to that of the placenta. It contains less water and
more globules than that of the same child some time after birth.
The placenta supplies the place of breathing to the child. We
see that, like the lungs, it furnishes the blood with an additional
quantity of globules.
VENOUS BLOOD DURING VARIOUS DISEASES.
The colour of venous blood varies in different diseases. In
inflammatory fever it is more scarlet, or approaches somewhat to
that of arterial blood. In Asiatic cholera, scurvy, and typhus, it
has a deep -red colour approaching to black.
The specific gravity increases in inflammatory diseases and in
certain phlegmasia3, also in the common cholera, and in certain
dropsies. It diminishes in scurvy, putrid disease, different ca-
chexiaB, such as diabetes, scrofula, chlorosis, copious hsemorrha-
gies, typhus and malignant exanthemata.
The smell changes completely in scurvy, confluent small-pox 9
and putrid fevers.
When healthy blood is drawn from a vein it always, after
a certain interval of time, separates into serum and crassamen.
turn. In disease it sometimes coagulates more rapidly than in
» Ann. de Chim. et de Phys. xxiii. 57,
374 LIQUID PARTS OF ANIMALS.
health ; sometimes more slowly, and sometimes so imperfectly
that the clot bears a stronger resemblance to sanies than to the
crassamentum of healthy blood. It coagulates more rapidly in
inflammatory diseases, and in cases of plethora ; more slowly in
putrid fevers, scurvy, and other cachexise.
The crassamentum is bulky and consistent in plethoric and in-
flammatory diseases ; but small, soft, and diffluent in scurvy and
typhus. In very malignant diseases, as the yellow fever, it lets
fall a black pulverulent sediment.
After great hsemorrhagies, in asthenic diseases, and in affections
of the heart, the serum is very abundant compared with the cras-
samentum. Its colour is deep-yellow in jaundice, lemon-yellow
in inflammatory diseases, muddy, and whitish in puerperal fe-
ver.
Sometimes a kind of crust covers the crassamentum, usually
distinguished from its colour by the name of the buffy coat.
This is the case in inflammatory diseases, in intermittent fevers,
and in the yellow fever. This crust seems to be fibrin, and its
position is probably owing to the globules being deposited more
rapidly than in healthy blood.
MM. Andral and Gaverrey have examined the blood in 360
cases of patients in the Hospital de Charite in Paris.* They
have drawn from this examination the following general results :
1. In acute inflammation, as rheumatism, pneumonia, bronchi-
tis, pleurisy, peritonitis, amygdalites, erysipelas, and pulmonary
tubercles, the fibrin of the blood increases.
2. In pyrexia, both typhoid and non-typhoid, eruptive fe-
vers, as small-pox, measles, scarlatina, and in intermittent fevers,
the globules increase while the fibrin remains normal or dimi-
nishes.
3. In chlorosis the globules diminish.
4. In the malady of Bright the albumen diminishes.
Let us now endeavour . to point out the alterations which the
blood undergoes in certain diseases. On this subject a great
many important facts have been collected by M. Lecanu.f It
will be sufficient here if we lay before the reader an abstract of
his researches.
1. Blood of infants attacked with induration of the cellular tis-
* Ann. de Chim. et de Phys. Ixxv. 225.
t Etudes Chimiques sur le Sang Hum. p. 94.
BLOOD. 375
sue. — Blood obtained by incisions into the skin of children who
died of this disease contained, according to Chevreul, water,
globules, and a fibrinous matter, possessed of little tenacity.
The serum separated from the crassamentum was almost colour-
less. In a few minutes it assumed the form of a jelly, owing
probably to some change in the state of the albumen.
2. Menstrual Blood. — This blood is a mixture of arterial blood
and mucous matter, varying in proportion according to circum-
stances. That of a woman, 27 years of age, analyzed by Dr
Dennis, contained,
Water, - . . 825-0
Globules, . 64-4
Albumen, . 48*3
Extractive matter, . 1*1
Fatty matters, . 3-9
Salts, . . 12-0
Mucus, . . 45-3
1000-0
It has usually a dark-red colour, a peculiar smell, and, instead
of crassamentum, contains small clots of little consistency.
Dr Rainy, Professor of Forensic Medicine in the University
of Glasgow, analyzed a quantity of menstrual blood, obtained by
puncturing an imperforated hymen. It was above six weeks old,
but not much putrid. It was quite fluid, and could easily be
poured and even dropt from a phial. It was browner in the co-
lour than ordinary blood, somewhat foetid, and disengaged am-
monia on the addition of potash. When examined under the
microscope, the globules were seen apparently as numerous as
in ordinary blood ; but their shape was somewhat irregular, as
is usually the case with putrid blood. It was composed of
Water, . 88-55
Solid residue, . 11-45
100-00
Mr Macconechy found the serum of this blood composed of
Water, . 91-28
Solid residue, . 8-72
100-00
LIQUID PARTS OF ANIMALS.
From this analysis Dr Rainy concludes that the blood consist-
ed of
Serum, . 97*22
Globules, . 2-78
100-
Dr Rainy could detect no fibrin in this menstrual blood.
Mr Macconechy analyzed the serum of this blood, and ob-
tained,
Water, . . 91-28
Albumen, . . 7-70
Common salt, . ' . 0-60
Soda, ; k * • 0-02
Animal matter,
Earthy phosphates, /
100-00
3. Blood of a patient labouring under Hcematuria. — The re-
markable circumstance in the blood in this disease is the total
absence of colouring matter, as may be seen by the action of acids
on healthy blood, and the blood in a case of ha3maturia.
Coagulum by In Healthy Blood. In Hrematuria Blood.
Sulphuric acid Blackish red Blackish brown
Nitric acid Blackish red White
Muriatic acid Red White *
4. Blood in Scurvy. — According to Fourcroy, blood drawn
from the gums of a person labouring under scurvy contains no
fibrin, does not coagulate, and becomes black on cooling. Ac-
cording to Deyeux and Parmentier, the blood of persons ill of
scurvy has a peculiar smell. The crassamentum from the blood
of three different scurvy patients was as firm, and contained as
much fibrin, as that of healthy blood. But the serum was diffi-
cultly coagulable by heat. One of the three crassamenta was
covered with the buffy coat. These facts are of little value, hav-
ing been determined at a time (1793) when the chemical inves-
tigation of animal substances had made too little progress to ex-
pect accurate experimenting.
5. Blood in Diabetes. — The opinion advanced by Dr Rollo,
that the blood in diabetes contains sugar, has not been verified by
future experimenters. Since neither Nicolas and Gueudville;
* Delarive, as quoted by Lecanu.
BLOOD. 377
Vauquelin and Segelas, Wollaston and Marcet, who examined
diabetes blood in succession, were able to detect any. I think it
probable that it exists, but in so small quantity as not to be re-
cognizable ; being constantly removed as fast as formed by the
action of the kidneys. Just as urea cannot be discovered in
healthy blood, though the experiments of Prevost and Dumas show
clearly that it must exist in that liquid. Henry and Soubeiran
analyzed the blood of a diabetes patient in 1826, and obtained,*
Globules, . 122-80
Albumen, , 55-48
Salts, . 5-57
Water, . 816-15
1000-00
The proportion of globules rather less than in healthy blood.
This confirms the previous statement of Nicolas and_Gueudville,
that the globules diminish as the disease advances.
Dr G. O. Rees has also analyzed the serum of blood drawn
from a diabetes patient, and obtained
Water, . 908-50
Albumen, (containing oxide of iron and phosphate of lime,) 80-35
Fatty matters, . . . .0-95
Diabetes sugar, . . . 1-80
Animal extract soluble in alcohol and urea, . 2-20
Albuminate of soda, . . . 0-80
Alkaline chloride with trace of phosphate, 1 A.AC\
Alkaline carbonate, trace of sulphate, /
Loss, v • . . . 1-00
1000-00 f
Dr Rees is the only chemist who has succeeded in finding su-
gar in the serum of diabetes blood, and his method of proceeding
is not satisfactory.
6. Blood in Jaundice. — Many experiments have been made to
determine whether bile exists in the blood of patients labouring
under jaundice. But the question seems still undecided. The
reason probably is that we are not in possession of any very de-
licate test of choleic acid. To decide the point, the best way
would be to mix a quantity of fresh bile with new-drawn blood,
and to make a comparative set of experiments on this mixture
* Jour, de Pliarmacie, xii. 320. f Phil. Mag. (3d series), xiii. 395.
378 LIQUID PARTS OF ANIMALS.
and pure blood. Probably some differences would present them-
selves, which might lead to important conclusions respecting ic-
teric blood. MM. Orfila and Clarion are of opinion that bile
exists in icteric patients ; Thenard and Lassaigne that such blood
contains no traces of bile ; while Chevreul, Boudet, Collard de
Martigny, and Lecanu believe that icteric blood contains the co-
louring matter of bile, but none of its other constituents.
Chevreul found in the blood of icteric children three colour-
ing matters, one orange-red, another green, and a third blue ;
which he considers as identical with the colouring matters in hu-
man bile. Collard de Martigny found in the blood of an icteric
woman, besides the usual constituents,
1. A yellow matter, characterized by its solidity, its colour, its
insipidity, want of odour, and insolubility in water and alcohol.
It is almost insoluble in muriatic acid, which gradually gives it
a green colour. It is very soluble in potash, from which it is
precipitated by the acids. It is very little soluble in nitric acid,
but assumes from it a green colour.
2. A green matter, which is soft and elastic, of a deep-green
colour, without smell, acrid, soluble in potash, to which it com-
municates a brown colour.
It appears from the analysis of Lecanu, that the blood of per-
sons afflicted with jaundice contains fewer globules than healthy
blood. He obtained in two different trials,
Water, ., 828-66 830
Albumen, 76-82 65
Salts, &c. . 14-90 8
Globules, . 79-62 97
1000-00 1000
The mean quantity of globules in 1000 of healthy blood is 132-49,
and the minimum quantity 115*85.
7. Blood in Asiatic Cholera. — The blood in this disease has a
much greater consistency than healthy blood. It contains a much
greater quantity of fixed matter, and much less water than healthy
blood. This will appear from the four following experiments of
Lecanu :
1st 2d. 3d. 4th.
Fixed matters, . 340 251 520 330
Water, 660 749 480 670
1000 1000 1000 1000
BLOOD.
379
The quantity of alkalis is greatly diminished, and it is remark-
able that the excrement and matter vomited by cholera pa-
tients contain alkali. The fibrin is diminished, but the globules
are very much increased in quantity.
Wittstock and Herrman could detect no urea in cholera
blood, but Marchand and Dr Nagel detected it in the blood of
a cholera patient who had passed no urine for three days.*
8. Blood in Yellow Fever. — According to Steevens the blood
in yellow fever is very thick, has a very dark colour, and con-
tains less than the usual quantity of salts. This exactly corre-
sponds with the state of the blood in Asiatic cholera.
9. Blood in Typhus Fever. — The small bulk of the crassamen-
tum, and its want of consistency in the blood of typhus patients,
has been long remarked. This would indicate a diminution in
the quantity of globules — an opinion confirmed by the two fol-
lowing analyses of M. Lecanu :
Water, . 805-2 . 795-88
Globules, . 115-0 . 105-00
Albumen, &c. 79-8 99-12
1000-0 1000-00
10. Mr Gulliver has detected pus in the blood in almost
every instance in which there was either extensive suppuration or
great inflammatory swelling without a visible deposition of pus
in any of the textures of the body. He considers the presence
of pus in the blood to be the proximate cause of sympathetic in-
flammatory, sympathetic typhoid, and hectic fevers, j
1 1 . Blood in diseases of the Heart. — M. Lecanu made several
analyses of the blood of patients affected with diseases of the
heart. The following table shows the results of these analyses :
• Albumen,
Water. salts, &c. Globules. Total.
1st male patient, . 821-02 77-59 101-39 1000-00
2d male patient, . 880-48 77-62 41-90 1000-00
3d male patient, . 807-27 96-35 96-38 1000-00
40-45 1000-00
51-49 1000-00
43-70 1000-00
45-49 1000-00
69-06 1000-00
. Mag. (3d series), xiii. 193,
1st female patient, . 873-45
86-10
2d female patient, . 868-62
79-89
3d female patient, . 866-61
80-69
4th female patient, 877-51
77-00
5th female patient, 845-14
85-80
* Poggendorf's Annaleri, xliv, 328-
t Phil.
380 LIQUID PARTS OF ANIMALS.
We see a great diminution in the globules and a proportional
increase in the water, albumen, and salts.
12. Blood in Chlorosis. — In this disease there appears to be a
great diminution in the globules of the blood, as appears from
the following analysis of the blood of a chlorotic patient by M.
Lecanu :
Water, . 862-40
Globules, 55.15
Albumen, &c. 82-45
1000-00
A second analysis of the blood of the same patient made some
months later gave,
Water, ^ - 861-97
Globules, 51-29
Albumen, &c. 86-74
1000-00
Foedisch made two comparative analyses of healthy blood and
chlorotic blood. The result is as follows :
Cruor. Serum. Fibrin. Water. Iron.
Healthy blood, . 124-00 86-01 25-11 756-87 8-01
Healthy blood, . 144-00 89-20 25-01 732-73 9-01
Chlorotic blood, . 91-41 93-61 6-40 826-28 3-30
Chlorotic blood, . 85-90 92-21 6-31 830-75 5-01
It was in consequence of the supposed diminution of iron which
was believed to be the colouring matter of blood that physicians
prescribed iron as a remedy in chlorosis.
] 3. Milky Blood. — In certain pathological states of the body
not yet well determined, the blood has such a resemblance to milk
that it has been compared to milk mixed with a little blood.
This was for a long time ascribed to the mixture of milk with the
blood. But analysis has shown that this blood does not contain
the constituents of milk ; but that its milky appearance is owing
to the existence of fatty matters held in suspension in it. The
following analysis of such a blood by Lecanu shows this very
clearly :
BLOOD. 381
Water, . .794
Albumen, . 64
Acid soap,
Cholesterin (1-08)
Olein, . )> 117
Margarin,
Stearin,
Salts, &c. . 25
Hematosin, trace.
1000
The analysis of Dr Christison of Edinburgh agrees with that of
Lecanu.
14. Injection of salts into the blood of living animals. — Mr
Blake has made a set of curious experiments on the action of salts
when thus injected.* He finds that salts with the same base have
generally the same action. The salts of magnesia when intro-
duced in any quantity arrest altogether the action of the heart,
and produce a complete prostration of muscular power. The
salts of zinc are similar, but not so powerful. The salts of ba-
rytes, strontian, and lead, occasion contractions in the muscular
tissues, which continue many minutes after death. The salts of
silver and soda produce a remarkable action on the pulmonary
tissue, which seems to occasion the death of the animal.
The preceding account applies almost exclusively to human
blood. Few experiments have been made on the blood of
the inferior animals. There cannot, however, be a doubt that
the blood of every species of animal has something peculiar, and
adapted for the animal in whose blood-vessels it flows. This
is evident from the facts observed when blood is transfused
from one animal to another. It is well known that when a
blood-vessel in a living animal is opened, and the blood allow-
lowed to flow out, the animal loses all sense and motion, and
speedily dies. But if the blood of another animal of the same
species be made to flow into the vessels of the exhausted animal,
it speedily recovers its sensibility and power of motion, and sus-
tains no perceptible injury. The blood of a sheep in this way
may be transfused without injury into another sheep. But if we
transfuse the blood of a sheep into a cat or a dog, the animal dies.
This must be owing either to a diversity of the proportion of the
• Phil. Mag. (3d series), xviii. 547.
382 LIQUID PARTS OF ANIMALS.
constituents of the blood in different animals, or to a diversity in
the constituents themselves. The few analyses of the blood of
inferior animals are not capable of enabling us to decide this
point ; but it may be worth while to state here the principal facts
which have been ascertained.
1. Ox blood. — Lecanu analyzed the hematosin in ox blood
and obtained,
Carbon, . 66-49 . 65-91
Hydrogen, . 5.30 . 5-37
Azote, J 10-54 . 10-54
Oxygen, . 11-01 . 11.75
Iron, . 6-66 . 6-58
100-00 100-15
Two analyses of dried ox blood were made in Liebig's laboratory
by Messrs Playfair and Bockmann. They obtained,
Playfair. Bockmann.
Carbon, if.-u;; 51-950 . 51-965
Hydrogen, . 7.165 . 7-330
Azote, . 17-172 • 17-173
Oxygen, . • 19-295 91-115
Ashes, . 4-418 . 4-413
100-000 99-996
2. Horse's blood. — The following table shows the difference in
the proportion of water and solid matter in the arterial and ve-
nous blood of the horse :
I. — Arterial Blood.
Water. Solid matter.
From the aorta, . 783-83 . 216.17
From the carotid, . 785-50 • 214-50
II. — Venous Blood.
Water Solid matter.
795-67 • 204-32
804-55 . 195-45
According to Magnus 1000 volumes of horse's blood gave
47 volumes of carbonic acid,
12 volumes of oxygen,
7 volumes of azote,
while 1000 volumes of calf's blood gave
SALIVA. 383
55 -6 volumes of carbonic acid,
9 '6 volumes of oxygen,
6 '4 volumes of azote.
3. Blood of birds. — Prevost and Dumas found the blood from
the jugular vein of the following birds composed of,
Clot. Serum. Water.
A young raven, 14-66 • 5-64 . 79-70
A heron, , 13-26 . 5-92 . 80-82
A duck, . 15-01 . 8-47 . 76-52
A hen, ?i.«r 15-71 . 6-30 . 77-99
A pigeon. . 15-57 . 4-69 . 79-74
The facts just stated, few and imperfect as they are, show clear-
ly that the constitution of the blood is different in different ani-
mals.
CHAPTER II.
OF SALIVA.
THE saliva is a liquid secreted by six glands, three on each
side of the mouth. These are the two parotids, the two submaxil-
lary, and the two sublingual.
It is a liquid, which is colourless or nearly so. It is not quite
transparent, containing a few white flocks, which gradually sink
to the bottom, when the saliva is collected in a glass. Probably
these flocks come from the mucus which lines the ductus stenoni-
anus and the other salivary ducts.
It is not easy to form a notion of the quantity of saliva secret-
ed by the salivary glands ; though it must be considerable. M.
C. G. Mitcherlich collected all the saliva from one of the paro-
tid glands of a patient in an hospital in Berlin, who had a fistu-
la in that parotid. In 24 hours it amounted to 1048 grains.
Hence in this case the two parotids must have secreted 2096 grains
in 24 hours. The submaxillary and sublingual glands are much
smaller than the parotids. But if we suppose them equal to one
parotid, the whole saliva secreted in 24 hours will be 3144 grains,
or almost 7J ounces avoirdupois.*
* Poggendorf s Annalen, xxvii. 320.
384f LIQUID PARTS OF ANIMALS.
Most persons swallow their spittle once every two minutes.
The average weight of the saliva taken into the stomach each
time is 6*7 grains. This (in 16 hours) would amount to 3216
grains, or 7£ ounces. This estimate, (allowing eight hours for
sleep, during which little saliva is secreted,) comes very near
the estimate of Mitcherlich.
Haller informs us that 120 Ibs. of saliva were emitted during
the treatment of a syphilitic patient : but he does not say how
long the treatment continued.*
Saliva in the mouth varies somewhat in its nature. Most
commonly it is very slightly acid, though sometimes it is neutral,
and sometimes alkaline. The saliva collected by Mitcherlich
from the fistula during meals was acid ; but at other times alka-
line. During meals it was secreted so abundantly that it could be
collected in drops. At other times the flow was much smaller.
Tiedemann and Grmelin assure us that, when pure, saliva is
always alkaline ; and the same statement has been made by Dr
Donne, f M. Boudet has shown that the saliva and the mucus
secreted in the mouth are always alkaline ; but that the secre-
tion from the gums is always acid.J
The specific gravity of saliva varies somewhat, as may be seen
from the following table :
I found it in a case of salivation, . 1*0038
Tiedemann and Gmelin found it, . 1-0043
Mitcherlich, from . . 1-0061 to 1-0088
About dinner, Mitcherlich found it, . 1-0074
Mean gravity, . . 1-00518
It has been already observed, that saliva contains white flocks,
which gradually subside to the bottom. Mitcherlich found that
29-797 of saliva deposited 0-0015 of these white flocks. Accord-
ing to this estimate, 100000 parts of saliva contain nearly five
parts of white flocks. In another experiment the quantity was
greater. Berzelius estimated the quantity much higher, rather
more than T G\ ^th of the whole. Part of this difference probably
arises from the different temperatures at which the flocks were dried.
These white flocks are insoluble in water, alcohol, and acids.
They are soluble in potash, and the solution is precipitated by
acid. When the flocks are dried they assume a brown colour.
* Elem. Phys. lib. xviii. f Jour, de Pharm. (3d series,) i. 395.
$ Ibid. p. 396.
SALIVA. 385
Saliva freed from these flocks is quite transparent, often colour-
less, but sometimes it acquires a yellowish hue. At least a phial
of saliva which I have kept for 25 years has assumed a rather
deep brownish yellow colour, but still retains its transparency.
Alcohol added to saliva occasions a white precipitate. On
heating the liquid this precipitate is partly redissolved ; but it
falls down again when the liquid cools.
Nitrate of silver throws down a precipitate easily soluble in
ammonia.
Tincture of nut-galls throws down a light brown precipitate,
soluble by heat, but again appearing when the liquid cools.
Acetate of lead throws down a copious white precipitate, not
soluble by heat, but disappearing on the addition of acetic acid.
Sulphuric acid gives a slight flocky precipitate.
Caustic potash or ammonia produces no sensible effect.
Treviranus first observed that saliva got a red colour when a
little perchloride of iron was mixed with it. Tiedemann and
Gmelin have inferred that this colour is produced by a minute
quantity of sulphocyanic acid contained in saliva. With me the
experiment does not succeed ; but I have been told by Dr Al-
exander Stewart, that the saliva of smokers was found to strike
a red with perchloride of iron. Would it not seem from this as
if the sulphocyanic acid in saliva were generated by the action
of tobacco smoke ?
Such are the effects of reagents upon saliva. Let us now see
what are its constituents.
Mitcherlich evaporated 66.775* parts of saliva, of specific gra-
vity 1 -0083, to dryness in vacuo over sulphuric acid. The resi-
due weighed 1*08 parts, or 1*617 per cent. It was divided by
means of water and alcohol into the four following portions :
1. Insoluble in water and in alcohol of 0.863, 0-281
2. Soluble in water, but not in alcohol of 0-863, 0-352
3. Soluble in water, but not in alcohol of 0-800, 0'296
4. Soluble in water, and in alcohol of 0*800, 0-192
1-121
Excess, . 041
1-080
* The quantity was 66'775 grammes, or almost exactly 1030 grains*
Bb
386 LIQUID PARTS OF ANIMALS.
The following are the characters of these four divisions :
1. The substance already mentioned as existing in saliva in
white flocks, and considered as mucus. It amounted in this case
to 0-42 per cent, of the saliva.
Acetic acid causes it to swell up and to become gelatinous. But
no solution takes place even at a boiling temperature. Sulphu-
ric acid gives it a red colour, but produces no further alteration.
Muriatic acid dissolves it, and the colour of the solution is blu-
ish. This colour is produced slowly when the acid is cold ; but
more rapidly at a boiling temperature. Ammonia behaves like
acetic acid. Caustic potash causes a slight swelling, scarcely
perceptible, but does not dissolve it.
2. The substance soluble in water, but insoluble in alcohol
of 0*863, and amounting to 0*527 per cent., is what chemists
have denominated salivin or ptyalin. Its characters were first
described by Berzelius.* It was afterwards examined by Leo-
pold Gmelin. The characters given by these two chemists dif-
fer in consequence of the different methods employed to obtain
the salivin. For heat alters its properties. Its characters have
been detailed in the first part of this volume, while treating of
animal substances.
3. The matter soluble in water, but insoluble in alcohol of
0*800, consists chiefly of the salts contained in saliva ; but is not
quite free from animal matter. It amounts to 0*443 per cent, of
the saliva. It has a yellow colour and does not deliquesce. Its
solution is not altered by chloride of barium, sulphuric or muria-
tic acid, corrosive sublimate, chloride of iron, nor by infusion of
nut-galls. Acetate of lead gives a white precipitate, not redis-
solved by acetic acid or water. Nitrate of silver throws down a
white precipitate soluble in ammonia. When burnt it gives out
the smell of animal matter, and leaves a coal containing potash
and soda. Probably the animal matter which it contains is salivin.
4. The matter soluble in water and in alcohol of 0*800,
amounted to 0*287 per cent It had a yellowish red colour, and
deliquesced rapidly if the alkali had not been neutralized. It
gave, when burnt, the same products as the other substances,
and left a potash and soda salt
The properties of this substance are best observed when the
saliva has been previously neutralized by sulphuric acid. If we
* Annals of Philosphy, (1st series,) ii. 380.
SALIVA. 387
expose the substance (No. 4) to the air after such neutralization
it absorbs moisture ; the animal matter is dissolved, while the
salts remain in crystals. The liquid being poured off is found to
contain no sulphuric acid. The animal matter thus separated
from the salts has a red colour and an acid reaction. With
acids, potash, ammonia, and corrosive sublimate, it gives no pre-
cipitate. Acetate of lead throws down a slight precipitate again
redissolved by boiling. Perchloride of iron gives a flocky red
precipitate not again dissolved by water. Nitrate of silver gives
a precipitate soluble in ammonia.
When sulphuric acid is added to saliva to neutralize the soda
which it contains, white flocks precipitate. These flocks consti-
tute salivary mucus. As they continue to fall till the soda is sa-
turated, and as no effervescence is perceptible, the probability is,
that the soda in saliva is in combination with this mucus. The
following table exhibits the saline contents of 100 parts of sali-
va as determined by Mitcherlich:*
Chloride of potassium,
Potash combined with lactic acid,
Soda combined with lactic acid,
Soda combined with mucus,
Phosphate of lime,
Silica,
0-494
Or nearly half-a per cent.
Berzelius made an analysis of saliva, probably about the year
1810 ;f though we did not become acquainted with his results in
this country till about the year 18134 According to him 100
parts of saliva consist of
Water, . . . 992-9
Salivin, .... 2-9
Mucus, . . . 1-4
Alkaline chlorides, . . 1-7
Lactate of soda with animal matter, 0'9
Soda, . . . 0-9
1000-7
* Poggendorfs Annalen, xxvii. 337.
f No such analysis is to be found in the 2d volume of his Djurkemien, pub-
lished in 1808.
f Annals of Philosophy, ii. 380.
388 LIQUID PARTS OF ANIMALS.
Tiedemann and Gmelin made a great many experiments on
human saliva, and on the saliva of the dog and the sheep.* They
found the specific gravity of saliva made to flow by the stimulus
of tobacco smoke to be 1-0043 at 53^°. It reacted feebly as an
alkali, and never was acid. The residue when evaporated to
dryness amounted to 1-19 or 1-14 per cent. This residue being
incinerated, left 0-25 of ashes, of which 0-203 were soluble, and
0-047 insoluble in water consisting of earthy phosphates.
100 parts of the residue obtained by evaporating saliva to dry-
ness being analyzed, yielded the following products :
1. Fatty matter, analogous to cerebrote, substances soluble in al-
cohol and water, extract of meat, chloride of potassium, lactate
of potash, sulphocyanate of potash, . . 31-25
2. Animal substance precipitated by cooling from the so-
lution of boiling alcohol with sulphate of potash and
some chloride of potassium, . . 1*25
3. Matters soluble in water only, viz. salivin, much phos-
phate, and a little of sulphate of an alkali, and chloride
of potassium, . . . 20-00
4. Substances neither soluble in water nor alcohol, viz.
mucus, a little albumen, with alkaline carbonate and
phosphate, _,>.,., . 40-00
92-5
The 8-5 per cent, deficient was probably owing to the residue of
soda still retaining water.
It may be worth while to notice the differences in the charac-
ters of salivin, as stated by Berzelius and Tiedemann and Gmelin.
Berzelius found it white, Tiedemann and Gmelin light yellowish-
brown.
Berzelius states it as soluble in water; Tiedemann and Gmelin
found that every time it was dissolved in water it left alight-brown
membranous residue.
According to Berzelius, it is not precipitated by infusion of
nut-galls, diacetate of lead, nor corrosive sublimate. According
to Tiedemann and Gmelin, it is precipitated not only by infusion
of nut-galls, but also by lime-water, solutions of alum, and by
neutral salts of copper, lead, and iron.
It is pretty clear that the salivin of Tiedemann and Gmelin
was mixed with the mucus of the saliva.
* Tiedemann and Gmelin sur la Digestion, i. 4.
SALIVA. 389
1. The saliva of the horse was examined by Lassaigne in 1821.*
It was colourless, had a slight smell, and on exposure to the air
become muddy, and let fall a white precipitate consisting of car-
bonate of lime mixed with a little phosphate. It was slightly al-
kaline, and when heated, let fall some flocks of albumen. Being
evaporated to dryness, it left 3| per cent, of matter consisting of
1. Animal matter soluble in alcohol.
2. Animal mater soluble in water.
3. Albumen.
4. Trace of mucus.
5. Chlorides of potassium and sodium.
6. Soda.
7. Carbonate of lime.
8. Phosphate of lime.
2. The saliva of the dog was pale yellow, mucilaginous, and
slightly muddy ; when evaporated, it left 2-58 per cent, of resi-
due. From this residue alcohol extracted common salt, with a
very little lactate of soda, and a mere trace of extract of meat.
The portion insoluble in alcohol consisted chiefly of salivin unit-
ed to soda. It possessed exactly the characters of salivin from
human saliva,
3. The saliva of the sheep was very liquid, and not mucilagi-
nous. Its taste was feebly saline, and its reaction was alkaline.
It left a residue, when evaporated to dryness, amounting to 1-68
per cent, of the saliva. This residue was a thick white membrane
which attracted some moisture when exposed to the air. Alco-
hol extracted from it common salt, and was reddened by per-
chloride of iron, indicating the presence of sulphocyanic acid.
The residue left by the alcohol yielded to water a mere trace of sa-
livin, but several saline substances. The insoluble residue was
brittle and membranous. It did not dissolve nor gelatinize in
acetic acid. 100 parts of this saliva contained,
1. Water, . . . 98-90
2. Masters soluble in alcohol, viz. much extract of meat, a
substance which caused common salt to crystallize in oc-
tahedrons, common salt, and a little sulphocyanate of
soda, . . . O'll
3. Matters soluble only in water, viz. traces of salivin,
much phosphate of soda, much chloride of potassium and
carbonate of soda, . . 0'82
* Ann. de Chim. et de Phys. xix. 176.
390
LIQUID PARTS OF ANIMALS.
4. Matters insoluble in water and alcohol, viz. mucus or
coagulated albumen, a little phosphate and carbonate of
lime. . . . .0*05
99-88
It would appear from an observation of Leuchs that, when starch
is boiled with saliva, the solution becomes more liquid, and ac-
quires a sweet taste.* From this it would seem that saliva is ca-
pable of converting starch into sugar. He found that neither
albumen, gelatin, nor salivin possessed this property.
The saliva is sometimes liable to undergo morbid alterations.
There are two cases on record in which it contained a good deal
of oxalic acid. Clerc mentions that he has sometimes observed
the saliva in diseased persons acid and sometimes alkaline;
but he does not seem to have made any observations to deter-
mine the nature of the acid or alkali present. It varies much
in quantity and consistence : but no accurate set of observations
has yet been made upon the alterations induced in saliva during
various diseases. According to Dr Donne, the saliva becomes
acid when inflammatory diseases of the stomach exist, and it as-
sumes its natural state of alkalinity as soon as that inflammatory
affection ceases.f
Depositions from the saliva are frequently observed on the
teeth. Such depositions are known by the name of tartar. It
is a yellowish white bony-looking concretion, which gradually
accumulates on the teeth unless they be regularly cleaned. At
first it is little else than the mucus of the salivary ducts, which
gradually adheres to the teeth and becomes discoloured. But
by degrees subsesquiphosphate of lime appears, augments the
deposit, and renders it harder.
Tartar, according to the analysis of Berzelius,| is compos-
ed of,
Earthy phosphates, . t 79*0
Mucus, . . >V 12«5
Salivin, . . •*. 1-0
Animal matter soluble in muriatic acid, • 7-5
100-0
* Poggendorf s Annalen. xxii. 623.
f Ann. de Chim. et de Phys. Ivii. 414.
| Annals of Philosophy, ii. 381.
SALIVA. 391
The result of my analysis of a specimen of tartar, for which I
was indebted to Alexander Nasmyth, Esq., Dentist in Lon don
is as follows :
Subsesquiphosphate of lime, . 65 '61
Carbonate of lime, . 7*18
Silica with trace of iron and perhaps magnesia, 1-32
Fixed alkaline chlorides, . 1*43
Mucus and albumen, . 1O49
Salivin, . . . 1-32
Animal matter soluble in muriatic acid, . 6 '02
Water, . . . 6-63
100-00
The earthy salts were obtained by digesting the tartar in very
dilute muriatic acid. The acid being drawn off, was neutraliz-
ed and then mixed with caustic ammonia, which threw down the
calcareous phosphate. Oxalate of ammonia threw down the
lime left in solution. The residual liquid being evaporated to
dry ness and ignited, a chloride of potassium and sodium re-
mained, which, being dissolved, left a few black flocks, which, by
digestion in nitric acid, became brown, and before the blowpipe
exhibited the characters of silica tinged with iron. The bead with
carbonate of soda was opal. Hence I suspected the presence of
magnesia.
The water was determined by heating a portion of the tartar
over the steam-bath till it ceased to lose weight. The tartar
being digested in water a portion was dissolved. The water be-
ing evaporated, the residue was white ; but became yellow when
heated, and ceased to be quite soluble. Hence (abstracting the
chlorides present) it was considered as salivin. The animal mat-
ter remaining after the tartar had been treated with muriatic
acid, water and alcohol was considered as mucus. I think it
probable that the animal matter dissolved in muriatic acid was
salivin ; but I did not succeed in getting it unaltered from that
solution, and could not therefore examine its properties.
392 LIQUID PARTS OF ANIMALS.
CHAPTER III.
OF THE LIQUID OF RANULA.
THE term ranula is applied by French medical men to a soft
whitish oblong indolent tumour, situated under the tongue, near
the anterior ligament. This tumour is occasioned by the reten-
tion and accumulation of the saliva in the excretory ducts of the
maxillary and sometimes of the sublingual glands. As this li-
quid consists of altered saliva, it will be proper to give an ac-
count of it here. The only modern chemist who has examined
this liquid is M. Leopold Gmelin of Heidelberg.* It was ex-
tracted from a tumour of ten years standing. The liquid was
thick and adhesive like white of egg. It had a yellow colour,
was muddy, and reddened litmus-paper.
A portion of it was mixed with four times its bulk of water.
At first it did not seem soluble, but by long agitation it dissolv-
ed with the exception of a few very fine flocks. They were sepa-
rated by the filter, but were so few that they could not be per-
ceived when the filter was dried. The colourless solution froth-
ed strongly when agitated, was still gelatinous, and when mixed
with muriatic acid, gave, after some time, a copious white preci-
pitate. With nitric acid it gave a yellow precipitate. With al-
cohol, thick white flocks, and with tincture of nut-galls, cheesy
brown-yellow flocks. By potash it was not altered.
The greatest part of the liquid, amounting to 4-132 grammes,
was evaporated to dryness over the water-bath. By the action of
a boiling temperature it was white, almost opaque and cohered
into one mass. It weighed 0*223 gramme, or 5-4 per cent. It
was softened by water and then washed on the filter.
The aqueous liquid when evaporated left a minute quantity of
brownish yellow residue, which was deliquescent. It was treated
with alcohol, which dissolved a trace of yellowish-brown deli-
quescent abstract. Its solution in water gave, with acetate of
lead, white flocks, and with tincture of nut-galls, brown flocks,
and with nitrate of silver, a caseous precipitate. Perchloride of
iron gave a deep reddish-yellow colour, destroyed by dilute mu-
riatic acid. Hence it did not proceed from sulphocyanic acid.
* Ann. der Pharm. xxxi. 95.
GASTRIC JUICE. 393
This extract contained osmazome, common salt, and acetate of po-
tash.
The portion of the watery extract insoluble in alcohol was
merely a trace. It probably consisted of carbonate and phos-
phate of potash, and a small quantity of salivin.
The matter which had been treated with cold water was boil-
ed in alcohol. The alcohol when evaporated left a substance
like tallow, whose alcoholic solution did not redden tincture of
litmus.
The portion insoluble in alcohol, which constituted the princi-
pal part of the liquid of ranula, possessed the characters of co-
agulated albumen.
It appears from this analysis, imperfect as it is, that the liquid
of ranula has no resemblance to saliva ; being destitute of sul-
phocyanic acid, and almost so of salivin, while it contains abun-
dance of albumen, which is not found in saliva.
CHAPTER IV.
OF THE GASTRIC JUICE.
THE change which the food undergoes in the stomach was as-
cribed at first to the mechanical action of the stomach, but this
opinion was gradually abandoned, and chemical physiologists were
almost unanimous in assigning fermentation as the agent, though
what was meant by fermentation is far from clear. The nume-
rous experiments of Reaumur, Stevens, and Spallanzani, de-
monstrated that the change of food in the stomach was owing to
its solution in a liquid. This liquid was admitted to be secreted
in the stomach, and was therefore called gastric juice (succus
gastricus.) It seems needless to relate the attempts to collect this
liquid by Spallanzani, Gosse, Brugnatelli, Carminati, &c. be-
cause they were unsuccessful. The first important step to de-
termine its nature was by Dr Beaumont of the United States
army. He has published a very interesting set of experiments
on the human gastric juice,* which tend to throw a great deal of
* The original work, entitled " Experiments and Observations on the Gas-
tric Juice and the Physiology of Digestion," was published in America in 1833.
A new edition, edited by Dr Combe, appeared in Edinburgh in 1838.
394 LIQUID PARTS OF ANIMALS.
new light on the process of digestion. Alexis St Martin, who
was the subject of these experiments, was a Canadian of French
descent. He had been engaged in the service of the American
Fur Company, and was accidentally wounded by the discharge
of a musket on the 6th of June 1822. The charge, consisting
of powder and duck shot, was received on the left side, distant
not more than a yard from the muzzle of the gun. The contents
entered posteriorly, and in an oblique direction, forward and in-
ward, blowing off integuments and muscles of the size of a man's
hand, fracturing and carrying away the anterior half of the sixth
rib, fracturing the fifth, lacerating the lower portion of the left
lobe of the lungs and the diaphragm, and perforating the sto-
mach. He came under the surgical treatment of Dr Beaumont,
fevered, and for some time all the food taken into the stomach
made its way through the perforation. Gradually, however, this
was prevented by compresses applied to the opening into the sto-
mach. By degrees the injured parts sloughed off, and the pro-
truded portions of the stomach adhering to the pleura costalis and
the external wound, a free exit was afforded to the contents of
that organ, and effusion into the abdominal cavity was thereby
prevented. In about a year and a half after the accident, the
whole was healed, and the health and strength of St Martin
completely restored, but the perforation of the stomach still con-
tinued. It was situated at the left and upper side of the great
curvature. The external opening was about two inches below
the left nipple, on a line drawn from the nipple to the left ileum.
At the point where the lacerated edges of the muscular coat
of the stomach and the intercostal muscles met and united with
the cutis vera, the cuticle of the external surface and the mucous
membrane of the stomach approached each other very nearly.
They did not unite like those of the lips, nose, &c. but left an in-
termediate marginal space of appreciable breadth, completely
surrounding the aperture. This space was about a line wide ;
and the cutis and nervous papillae were unprotected, and as sen-
sible and irritable as a blistered surface abraded of the cuticle.
At first, when the stomach was empty, a portion of the mucous
coat was protruded by the orifice to the size of a hen's egg, but
there was no difficulty in reducing it by gentle pressure with the
finger or a sponge wet with cold water, neither of which produ-
ced the least pain.
4
GASTRIC JUICE. 395
The perforation was about two inches and a half in circumfe-
rence ; and at first the food and drink constantly exuded unless
prevented by a tent, compress, and bandage. During the win-
ter of 1823-4, a small fold or doubling of the coats of the sto-
mach appeared, forming at the superior margin of the orifice,
slightly protruding and increasing till it filled the aperture, so as
to supersede the necessity of the compress and bandage for re-
taining the contents of the stomach. This valvular formation
adapted itself to the accidental orifice so as completely to pre-
vent the efflux of the gastric contents when the stomach was full,
but it was easily depressed by the finger, so as to give free ac-
cess to the cavity of the stomach, and allow the introduction and
removal of any substances, the digestibility of which was an ob-
ject of experiment.
Dr Beaumont had ample opportunity of viewing the appear-
ance of the inside of the stomach, as Alexis St Martin was his
servant for several years, and was subjected by him to various
courses of experiment, in order to determine the phenomena that
attend the conversion of food into chyme in the stomach.
The inner coat of the stomach in its natural and healthy state
is of a light or pale pink colour, varying in its hues according to
its full or empty state. It has a soft and velvety appearance, and
is covered with a very thin transparent viscid mucus lining the
whole interior of the organ.
Immediately beneath the mucous covering, and apparently
incorporated with the villous membrane, appear small, spheroidal,
or oval-shaped globules, from which the mucous matter appears
to be secreted.
When food or other irritants are applied to the innermost coat
of the stomach, innumerable minute lucid points and very fine
papillae can be seen (by means of a magnifying glass), arising
from the villous membrane, and protruding through the mucus,
from which distils a pure, limpid, colourless, slightly viscid fluid,
which constitutes the true gastric juice.
This liquid is invariably acid, while the mucous matter which
covers the inside of the stomach has no taste whatever. The gas-
tric juice thus discharged is absorbed by the aliment in contact
with it, or collects in small drops and trickles down the sides
of the stomach to the more dependent parts, and there mingles
with the food, or whatever else may be contained in the gastric
396 LIQUID PARTS OF ANIMALS.
cavity. It is never accumulated in the cavity of the fasting sto-
mach, and is seldom or never discharged, except when the ves-
sels secreting it are excited by the natural stimulus of food, by
mechanical irritation of tubes, or by other excitements. When
food is received, the juice is given out in exact proportion to its
acquirements for solution, except when more food has been taken
than is necessary for the wants of the system.
Probably the secretion from mechanical irritation is less than
that produced by the stimulus of food : the latter is diffused over
the whole villous coat, while the former is only partial. On
viewing the interior of the stomach, the peculiar formation of its
inner coats is distinctly seen. When empty, the rugae appear
irregularly folded on each other, almost quiescent, of a pale pink
colour, and lubricated with mucus. On the application of food,
the action of the vessels is increased, the colour brightened, and
the vermicular motion excited. The small gastric papillae begin
to discharge a clear transparent fluid, which continues to accu-
mulate abundantly as the food is received for digestion.
If the mucous covering of the villous coat be wiped off with a
sponge during the period of chymification, the membrane ap-
pears roughish, at first of a deep pink colour, but in a few se-
conds the follicles and fine papillae begin to pour out their re-
spective fluids, which, being diffused over the parts abraded of
mucus, restore to them their peculiar soft and velvety appear-
ance and pale pink colour ; and the gastric juice increases and
trickles again down the sides of the stomach.
If the mucus be wiped off when the stomach is empty, a simi-
lar roughness and deep colour appear, though less in degree, and
the mucus is more slowly restored. The follicles swell more gra-
dually, and the fluids do not appear in such quantities as to
trickle down, the mucus alone being restored.
In disease, the inner membrane of the stomach presents vari-
ous and essentially different appearances. In fever, obstructed
perspiration, undue excitement by spirituous liquors, or when
overloaded with food, while under the influence of fear, anger,
or whatever depresses or disturbs the nervous system — the villous
coat becomes sometimes red and dry, at other times pale and
moist, and loses its smooth and healthy appearance. The secre-
tions become vitiated, greatly diminished, or entirely suppressed.
The mucous covering can scarce be observed ; the follicles are
3
GASTRIC JUICE. 397
flat and flaccid, with secretions insufficient to protect the vascular
and nervous papillae from irritation.
Sometimes eruptions or deep-red pimples appear on the inter-
nal coat of the stomach, not numerous, but distributed here and
there upon the villous membrane. They are at first sharp-point-
ed and red, but frequently become filled with white purulent
matter. At other times irregular, circumscribed red patches,
varying from half an inch to an inch and a half in circumference,
appear on the internal coat, seemingly the effect of congestion in
the minute blood-vessels of the stomach. At times, small aphthous
crusts in connection with these red patches are seen. Abrasion of
the mucus leaving the papillae bare for an indefinite space, is not
an uncommon appearance.
When these diseased appearances are considerable, and particu-
larly when there are corresponding symptoms of disease, as dry-
ness of the mouth, thirst, accelerated pulse, no gastric juice can be
extracted, not even on the application of the stimulus of food.
Drinks received into the stomach are immediately absorbed, none
remaining in that organ ten mi n utes after being swallowed. Food
taken during this condition of the stomach remains undigested for
forty-eight hours or more, increasing the derangement of the
whole alimentary canal, and aggravating the general symptoms
of disease.
After excessive eating and drinking chymification is retarded,
and, although the appetite is not always impaired at first, the
fluids become acrid and sharp, excoriating the edges of the aper-
ture, and almost invariably producing aphthous patches, and the
other indications of a diseased state of the innermost membrane,
which have been already mentioned. Vitiated bile is also found
in the stomach under these circumstances, and flocculi of mucus
are also much more abundant than in health.
Whenever the morbid condition of the stomach appears, there
is generally a corresponding appearance of the tongue. When
a healthy state of the stomach is restored, the tongue invariably
becomes clean.*
Dr Beaumont had an opportunity also of observing the peris-
taltic motion of the stomach during digestion. It causes the food
* See Beaumont's Experiments, Chapter vii. The above description of the
appearances of the stomach in health and disease has been given as nearly as
possible in the words of Dr Beaumont.
398 LIQUID PARTS OF ANIMALS.
to revolve round the stomach in from one to three minutes.
The consequence of this is a thorough mixture of all the differ-
ent articles of food with each other. If a mouthful of some te-
nacious food be swallowed after digestion is considerably ad-
vanced, it will be seen passing the opening to the great curva-
ture, and in the course of one and a half or two minutes, it will
reappear with the general circulating contents, more or less
broken to pieces or divided into smaller pieces, and it very soon
ceases to be distinguishable.
As the food becomes more and more changed from its crude
state to that of chyme, the acidity of the gastric juice is consi-
derably increased — more so in vegetable than in animal diet —
and the general contractile force of the muscles of the stomach is
augmented in every direction, giving the contained fluids an im-
pulse towards the pylorus. During the whole process of diges-
tion, the bulk of the food in the stomach is continually diminish-
ing ; slowly at first, but more rapidly towards the conclusion of
the chymification. Hence it must be passing through the pylo-
rus during the whole time of digestion.
The gastric juice was extracted from the stomach of Alexis
St Martin in the following way : He was placed on his right
side. The valve within the aperture was depressed, and a caout-
chouc tube of the size of a large quill was introduced five or six
inches into the stomach. He was then turned on his left side so
as to make the orifice dependent The stomach was empty and
contracted on itself. The tube acted as a stimulant, and the
gastric juice began to flow first by drops, and then in an uninter-
rupted, and sometimes in a continuous stream. Moving the tube
up and down, or backwards and forwards, increased the discharge.
The quantity of fluid obtained was from half-an ounce to two
ounces troy, according to circumstances. Its extraction was at-
tended by that peculiar sensation at the pit of the stomach, call-
ed sinking, with some degree of faintness, which rendered it ne-
cessary to stop the operation. The juice was usually extracted
early in the morning when the stomach was empty and clean.
The following is a description of the gastric juice thus extracted,
as drawn up by Dr Silliman, Professor of Chemistry in Yale-
College.
" The fluid, after having been kept in a closely-corked phial
more than three months, from April to August, and most of the
GASTRIC JUICE. 399
time in a cellar, remained unaltered, except the formation of a
pellicle on the surface, slightly discoloured by red spots. A se-
cond pellicle appeared after the precipitation of the first. It was
thicker and more discoloured with dark-red spots, like venous
blood.
" The fluid was cloudy, like a solution of gum-arabic ; but
when filtered, it became perfectly clear, and of a slight straw-yel-
low tinge.
" The pellicles, which had the appearance of inspissated mu-
cus, after being separated from the fluid, became, after exposure
to the air, throughout of a brownish red colour, resembling the
inner portion of a mass of coagulated blood. This change seems
to result from a sudden exudation.
" The fluid exhaled a slight odour, not disagreeable — rather
aromatic, and very similar to that which it at first exhaled, but
not so strong. It was then rather disagreeable.
" Taste feebly saline, not disagreeable.
" Test papers of litmus, alkaline, and purple cabbage were de-
cidedly reddened. Turmeric paper underwent no change, but
when previously browned by ammonia, the gastric juice restored
the yellow colour.
" Nitrate of silver gave a dense white precipitate, which, after
standing five minutes in the sun's light, turned to a dark brown-
ish-black, thus indicating muriatic acid. Muriate and nitrate of
barytes gave a slight opalescence, indicating a trace of sulphuric
acid. Probably there was also some phosphoric acid.
" Specific gravity about 1-005."
It was subjected to an imperfect chemical examination by Pro-
fessor Dunglison and Professor Einmit of Virginia College.
They found it to contain free muriatic and acetic acids, phosphates
and muriates, with bases of potash, soda, magnesia, and lime, and
an animal matter soluble in cold water, but insoluble in hot
It was shown many years ago by Spallanzani, and his experi-
ments were confirmed by those previously made by Dr Stevens,
that the gastric juice acts as a solvent to the food, and that it is
capable of dissolving the food out of the stomach, in phials, pro-
vided the temperature be kept as high as 100°, which is about
that of the human stomach during digestion. These conclusions
have been fully confirmed by Dr Beaumont, who not only wit-
nessed the solution of almost every kind of food in the stomach
400 LIQUID PARTS OF ANIMALS.
during chymification, but tried the effect of the gastric juice
upon the same kinds of food in phials at the temperature of 1 00°,
and found it to dissolve them precisely as happened in the sto-
mach, though in general after a longer interval of time.
Dr Beaumont has published the different series of experiments
which he made by introducing various articles of food into the
stomach, and noticing the time that elapsed before they were di-
gested. These experiments throw considerable light upon the
relative digestibility of different kinds of food, and on that ac-
count are highly deserving the attention of medical practitioners ;
but, as they do not throw much light on the nature of the gastric
juice, it would be improper to give an account of them here.
From the preceding account it will be seen, that there is a li-
quid secreted in the stomach during digestion, which has the pro-
perty of dissolving the food, and reducing it to a kind of pap, in
which the various articles of food are so much altered in their
appearance that they can no longer be recognized by their sensi-
ble properties. We know that during mastication a considera-
ble quantity of saliva is mixed with the food in the mouth, and
passes along with it into the stomach, so that the gastric juice
consists at least in part of saliva. Dr Prout has shown that the
gastric juice always contains free muriatic acid, and Tiedemann
and Gmelin that in animals which live on vegetables there is
always free acetic acid, and occasionally free butyric acid in the
stomach. Now it comes to be a question whether the saliva and
these acids be not capable of converting all kinds of food into
chyme, and therefore do not constitute the whole essential por-
tion of the gastric juice. The experiments of Eberle, M tiller,
and Schwan have shown that something more is necessary. The
following is an epitome of their very curious experiments.
1. There are certain articles of food that are dissolved in glass
tubes by saliva kept at the temperature of 100°. This is the case
with boiled starch, which, by digestion in saliva, is converted in-
to starch-gum and sugar.
2. There are certain other articles of food which are dissolved
in glass tubes filled with water, acidulated with muriatic or ace-
tic acid, and kept at the temperature of 100°. This is the case
with casein, gelatin, and gluten. At least the effects of the dilute
acids on these substances agree with what Tiedemann and Gme-
lin observed in natural digestion. Gelatin, for example, loses
GASTRIC JUICE. 401
its property of gelatinizing and of being precipitated by chlo-
rine.
3. But there are various articles of food which require another
digesting principle to convert them into chyme. This is the case
with coagulated albumen, fibrin, and (to a certain extent also)
casein. To make an artificial gastric juice, capable of dissolv-
ing these substances, a portion of the third or fourth stomach of
an ox was digested for twenty-four hours in water containing
2 f per cent, of muriatic acid, and the liquor was then filtered.
It contained in solution 2*75 per cent of solid matter, and re-
quired rather more than 2 per cent, of carbonate of potash to
neutralize it. When this liquid was digested for several hours
on coagulated albumen in powder, it dissolved.
Muller's experiments showed that the mere acid solution will
not dissolve albumen. And Eberle and Schwann found that the
same acid solution, after the third or fourth stomach of the ox
is digested in it, acquires the property of dissolving albumen. It
is clear from this, that something is taking up from these sto-
machs, which gives the acid liquor the power of dissolving albu-
men and fibrin. To this substance, in consequence of its digest-
ing property, Schwann has given the name of pepsin.*
The gastric juice, it would appear from these experiments,
consists of saliva, of muriatic and acetic acids, and of pepsin.
This last substance is obtained by digesting the third or fourth
stomach of the ox in a dilute solution of muriatic acid. Some
experiments were made by Schwann to determine the nature of
pepsin. . But they were not very successful. The facts ascer-
tained have been stated in a preceding chapter, when treating
of pepsin.
The most characteristic action of pepsin is its precipitating ca-
sein or coagulating milk. When 0*42 of pepsin solution is mix-
ed with 100 of milk, the milk is coagulated. The quantity of
the muriatic acid of commerce necessary to produce the same
effect is 3*3 per cent.
The neutralized solution of pepsin still coagulates milk. But
if its temperature be raised to the boiling point its property of
coagulating milk is destroyed.
The small quantity of pepsin which causes the solution of al-
bumen is remarkable. Acidulated water holding in solution
* From vt-^K, digestion.
C C
402 LIQUID PARTS OF ANIMALS.
only 4^th of its weight of pepsin shows a decided action on al-
bumen. 98 grains of water acidulated with muriatic acid, and
containing only 4-8 grains of the solution of pepsin, dissolve 49
grains of albumen in twenty-four hours, when kept at the tem-
perature of 99°.5. Now, as 4'8 grains of digesting liquor con-
tain only 0-11 grain of solid matter, while 49 grains of albumen,
when dried, leave about 10 grains of solid matter, it follows that
one grain of pepsin is capable of causing the solution of 100
grains of dry albumen.
When pepsin liquor is employed to dissolve albumen, it part-
ly loses its digesting power. Hence it must suffer an alteration
during the process.
It acts best at the temperature of 100°. But it will act also
at 54° or 55°, though not so well.
When the albumen has been previously reduced to a fine
powder, it is dissolved in from six to twenty-four hours. Fi-
brin is dissolved in from three to twelve hours. The presence
of atmospherical air is not necessary for these solutions, and no
gas is given out. Some salts, sulphate of soda, for example, hin-
der the digesting action of pepsin.
The solution of albumen in the pepsin liquor consists, accord-
ing to Schwann, of, 1. Altered albumen dissolved in the acid,
and precipitable by neutralizing that acid ; 2. Of osmazome ;
3. Of salivin. Flesh, both raw and roasted, is also dissolved by
the pepsin liquor ; but the process is slower.*
Vogel has shown that pepsin is not formed by the action of
the acid upon the mucous membrane of the stomach. For if
we digest the mucous membrane in pure water we obtain a li-
quor which possesses digestive properties. Other acids produce
the same effect as the muriatic. Vogel tried the sulphuric, ace-
tic, phosphoric, and nitric acids successfully. Phosphoric acid
answered best, and nitric acid worst of all these acids.f
Vogel examined also the changes produced upon albumen and
fibrin when dissolved in the pepsin liquor. It had been shown
by Eberle and Schwann, that the albumen, after being so dis-
solved, was not coagulated by heat, and was partly soluble in al-
cohol. The solution is muddy. Alcohol increases the muddi-
ness somewhat, Tannin throws down an abundant brownish-
* Schwann, Poggendorfs Annalen, xxxviii. 358.
t Jour, de Pharmacie, xxv. 648.
PANCREATIC JUICE. 403
white precipitate. Prussiate of potash a bulky white, and red
prussiate a green precipitate. Carbonate of soda throws down a
white gelatinous precipitate, soluble in water and alcohol. The
liquor is still precipitated by tannin but not by prussiate of po-
tash. It is also precipitated by acetate of lead and by a solution
of alum. Corrosive sublimate throws down a bulky white pre-
cipitate, and sulphate of copper an abundant greenish -blue pow-
der. Vogel analyzed this last precipitate, and found the albu-
men unaltered in its chemical constitution. Nor does the fibrin
dissolved in the pepsin liquor seem to have changed its nature.*
From the preceding detail, which has been lengthened out in
consequence of the obscurity of the subject, it appears that the
gastric juice is secreted only when the stimulus of food is applied ;
that it is a clear transparent liquid containing as essential ingre-
dients, about 2 1 per cent, of muriatic acid, and a certain pro-
portion of pepsin which has not been determined. Whether the
pepsin of the gastric juice be analogous to amygdalin of the al-
mond, has not been determined. It is much more probable that
it is a substance quite peculiar, formed in the stomach for the
express purpose of converting the food into chyme.
CHAPTER V.
OF THE PANCREATIC JUICE.
THE pancreas is a conglomerate gland resembling closely in its
appearance the parotid. It is about the size of a dog's tongue,
and extends from the spleen to the curve of the duodenum, rest-
ing over the spine. The duct, which conveys the liquid secret-
ed by the pancreas, was first demonstrated by John George Wir-
sung of Bavaria in 1641 ; though it is stated by Haller that it
was, pointed out to Wirsung by Maurice Hoffmann. Be that as
it may, Regnier de Graaf collected the gastric juice of a dog in
1664, and endeavoured to determine its nature. He opened the
duodenum, introduced a quill into the pancreatic duct, and al-
lowed the liquid to pass through it into a bottle. He describes
it as limpid and acidulous, or most commonly acidulo-saline.
* Jour de Pharmacie, xxv. p. 652.
404 LIQUID PARTS OF ANIMALS.
It was afterwards collected and examined by Sclmyl, Wepfer,
Pechlin, Brunner,- and J. Bohn ; the first of whom confirmed,
while the others combated the opinions of De Graaf. But, from
the infant state of chemistry at the time when they lived, their
examinations could scarcely lead to any satisfactory result.
After some progress had been made in the investigation of
animal fluids, a few observations on the pancreatic juice were
made by Mayer. Magendie also attempted to collect it, though
he succeeded in obtaining only a few drops. He found it yel-
lowish, saline, alkaline, and coagulable by heat.*
The most celebrated physiologists of the last century, Hoff-
mann, Stahl, Boerhaave, Haller, &c. concur in opinion, that the
pancreatic juice is of a similar nature with saliva. And this opi-
nion, founded on the similar appearance of the pancreas and pa-
rotids, was generally adopted. The experiments ofTiedemann
and L. Gmelin, detailed in their work on digestion, have at last
given us some facts, which will enable us to decide this long dis-
puted point.
They collected the pancreatic juice of the dog, the sheep, and
the horse, by the same method which had been previously em-
ployed by De Graaf, and which succeeded with them perfectly ;
though it had failed with Magendie.
It appears from their experiments, that the quantity of pan-
creatic juice secreted is not large. They found it always acid
when the animal was in full vigour ; but when its health and
strength were enfeebled by the painful situation in which it was
placed, the pancreatic juice became alkaline. In four hours
they collected from the pancreas of a large dog 154 grains of
pancreatic juice. After the experiment was finished, the glass
tube through which the juice had flowed was withdrawn, the ex-
cretory duct was tied up, the viscera replaced in the abdomen,
and the external wound closed by sutors. The animal gradual-
ly recovered, and continued in perfect health for eleven weeks.
He was killed, and the state of the excretory ducts of the pancre-
as examined. There were two pancreatic ducts in that dog.
The larger had been tied up, but the smaller, which entered the
duodenum along with the ductus communis choledochus, supplied
its place.
The pancreatic juice thus collected was opal coloured, and was
* Physiologic, ii. 367.
PANCREATIC JUICE. 405
thready, resembling white of egg diluted with water. It coagu-
lated when boiled, and likewise when mixed with nitric acid or
with alcohol. The first portion collected was acid, the last por-
tion alkaline, and was composed of,
Water, . 91-28
Solid matter, 872
100-
The solid matter consisted of osmazome, of a peculiar animal
matter, coloured red by chlorine, and discoloured by a larger
quantity of that reagent, and of casein and albumen. When this
solid matter was incinerated, it left carbonate of soda and chlo-
ride of sodium, with a trace of sulphate and phosphate of soda,
and of carbonate and phosphate of lime.
The analysis of the pancreatic juice of the dog gave,
Substances soluble in alcohol, . 3*68
Substances only soluble in water, . 1-53
Coagulated albumen, . . 3*55
Water, . . . .91-72
100-48
From this analysis it appears that the pancreatic juice of the
dog has no resemblance to saliva. The substance rendered red
by a little chlorine was soluble in alcohol and not in water. It
constitutes the peculiar and characteristic constituent of pancrea-
tic juice, and is therefore called pancreatin.
The pancreatic juice of the sheep was similar in appearance to
that of the dog, but more watery, the solid matter in it amount-
ing only to 3-65 per cent. This liquid was found to contain,
Matters soluble in alcohol, . 1-51
Matters soluble in water only, . 0-28
Coagulated albumen, . . 2 '24
Water, .... 96-35
100-38
From -the solid matter they extracted osmazome and casein, be-
sides the coagulated albumen. Whether any pancreatin existed
in it was doubtful. At any rate, the quantity was too small to
be detected.
The pancreatic juice of the horse was obtained from a horse
406 LIQUID PARTS OF ANIMALS.
which just before its death had eaten a quantity of oats. It had
a yellowish colour, was transparent, but slightly opaline, mucila-
ginous, and thready like white of egg. It slightly reddened tinc-
ture of litmus, coagulated by boiling, even after having been di-
luted with water. It was therefore quite analogous to the pan-
creatic juice of the sheep.*
From these experiments it follows that saliva and pancreatic
juice are different in their properties.
1. The solid matter in pancreatic juice of the dog is at least
twice as great as that in saliva.
2. Saliva contains mucus and salivin. If albumen or casein
be present, the quantity must be exceedingly minute ; but pan-
creatic juice contains a great deal of albumen and casein, and no
salivin or mucus.
3. Saliva is usually slightly alkaline, but pancreatic juice con-
tains a little free acid.
4. The saliva of the sheep and of smokers contains sulphocya-
nic acid, but there is no trace of it in the pancreatic juice of the
same animal.
5. The presence of casein in pancreatic juice was inferred, be-
cause this juice is not only precipitated by acids but by metallic
salts and the tincture of nut-galls ; but as albumen is precipitated
by these reagents as well as casein, the evidence for the exist-
ence of this last substance is not satisfactory. Should its presence
be hereafter proved by experiment, it is not unlikely that its office
may be to remove the pepsin from the chyme, which may be ne-
cessary in order to its conversion into chyle.
CHAPTER VI.
OF BILE.
THE bile is secreted by the liver, the largest of all the abdo-
minal viscera, and it makes its way into the duodenum by the
ductus communis choledochus. In man, the ductus communis and
the pancreatic duct usually enter the duodenum together, but in
the dog the pancreatic duct is commonly a good way lower
down than the biliary duct.
* Recherches sur la Digestion, i. 26.
BILE. 407
The liver is suppliecLwith blood partly by the hepatic artery
and partly by the vena portce, which enters the liver at the great
fossa, and brings to it the venous blood sent back by the princi-
pal abdominal viscera. The vena portce after entering the liver
subdivides into numerous branches like an artery, and there can
be little doubt that the blood which it supplies is employed in
the formation of bile, while the use of the blood which is sup-
plied by the hepatic artery is to nourish the liver. That the liver
is composed of globules like the other conglobate glands was first
pointed out by Malpighi. The best account of the structure of
this viscus has been given by Mr Kiernan.*
The hepatic ducts can be traced along the canals in the fissures
between the lobules and into the lobules where they form
plexuses. The branches of the portal vein and the hepatic arte-
ries also enter the lobules. The venous branches forming a plexus
which communicates with the incipient radicles of the hepatic
vein, and the arteries, which are very few and minute, are the
nutrient vessels of the lobules. The branches of the artery ra-
mify freely upon the coats of the portal vein and on the hepatic
ducts, furnish materials for the nutrition of both, and to the lat-
ter for the secretion of mucus, which lubricates their interior
coat.
Each lobule of the liver is found to consist of a reticulated
plexus formed by the minute radicles of the biliary ducts. For
these, when examined with a highly magnifying power, are seen
to divide and subdivide so as to form a mesh in its interior, which
is supported by a cellular tissue, furnished by Glisson's capsule.
Upon this mesh is disposed another formed by the terminal
branches of the vena portce. It is difficult to inject the ducts,
owing to their being filled with bile. Mr Kiernan succeeded by
first tying the portal vein and hepatic artery in a living animal
after feeding it. Thus the secretion of bile was suspended, and
that which the ducts contained discharged. The ducts cannot
be injected directly from the hepatic vein ; for no branches from
this vessel ramify on their coats. The residue of the blood con-
veyed by the hepatic artery to the lobules, to the different ves-
sels and to the ducts for their nutrition, is taken up by the mi-
nute veins, and conveyed to the vena portce ; so that part of the
blood from which bile is secreted is derived from the liver itself, f
» Phil. Trans. 1833, p. 711.
t See Quain's Anatomy, p. 650, and Kiernan's paper, as quoted above.
408 LIQUID PARTS OF ANIMALS.
Bile, after being secreted in these lobules of the liver, is con-
veyed by the small ducts to larger and larger ducts, till they
at last unite in one duct called the duclus hepaticus. In many
animals there is a cavity placed on the liver called the gall-blad-
der, into which the bile makes its way from the hepatic duct,
when not wanted for digestion. The duct by which it enters is
called the ductus cisticus. It joins the hepatic duct before it en-
ters the duodenum, and both together form one common duct
called the ductus communis choledochus.
From the large size of the liver and of the biliary ducts, the quan-
tity of bile thrown into the duodenum must be considerable ;
though it has not been in the power of physiologists to form any
accurate estimate of it. According to Leuret and Lessaigne,*
the bile secreted by the liver of the horse amounts to two ounces
in a quarter of an hour. This would make the enormous quan-
tity of twelve pounds a-day. But as the horse has no gall-blad-
der, it is probable that bile is only secreted, or at least given out
by the liver, when that organ is excited by the stimulus of chyme
in the small intestines.
Great attention has always been paid to this secretion by me-
dical men. The ancients ascribed a number of diseases and even
affections of the mind to its agency. Various observations on it
were made by Boyle, Boerhaave, Varheyen, Ramsay, and Baglivi.
The first attempt to examine it seems to have been made by
Neumann, f He describes the characters of ox -bile, and says, that
it is neither acid, nor alkaline, nor soapy. It is coagulated by
acids, and slightly precipitated by carbonate of potash. Ammo-
nia occasions no alteration. Rectified spirits scarcely make it
cloudy. He subjected it to distillation, and noticed some of the
products, viz. water, ammonia, and oil. The residue contained
a fixed alkali.
Cadet in his analysis of bile, \ published in 1767, added some
new facts. Alcohol throws down a substance from bile, which
he considered as gelatin. He shewed that the alkali in bile is
soda.
Van Bochoute, Professor at Louvain, wrote in 1778 a Latin
dissertation containing important observations respecting the na-
* Recherches Physiologiques et Chimiques pour servir a Ihistoire de la diges-
tion, p. 83.
•j- I quote from Lewis's translation, p. 566. This translation was published
in 1759, and contains much original matter.
Mem. Paris, for 1767, p. 471.
BILE. 409
ture of this liquor, the oily matter, and the means of separating
all the materials which constitute it.*
Thenard made an analysis of ox-bile, which was published in
1805.f According to this analysis, the constituents of ox-bile
are as follows :
Water, . . 700-0
Picromel and resin, . 84-3
Yellow matter, . 4-5
Soda, . . 4-0
Phosphate of soda, . 2-0
Common salt, . 3-2
Sulphate of soda, . 0-8
Phosphate of lime, . 1 *2
Oxide of iron, trace.
800-0
According to Thenard, the picromel constitutes the essential
constituent of bile. He obtained it by precipitating bile by means
of acetate of lead. The lead was separated from the picromel
by sulphuretted hydrogen ; or it may be precipitated from bile
by sulphuric acid. The green precipitate thus obtained was for-
merly called resin of bile. When it is digested in water over
carbonate of barytes, the picromel dissolves in the water in pro-
portion as the sulphuric acid is separated by the barytes. Pi-
cromel thus obtained has a greenish-yellow colour, a bitter taste,
and resembles inspissated bile in its appearance.
The yellow matter is the substance to which Van Bochoute
gave the name of fibrin, and which was considered by others as
albumen. It is probably mucus.
In his second memoir, Thenard takes a view of the nature of
the bile in different animals, and on the formation of biliary cal-
culi. He states the constituents of human bile to be:
Water, . . 91-
Insoluble yellow matter, 0-18 to 0-91
Albumen, . . 3.81
Resin, . . 3-74
Soda, . . 0-51
Salts,! . . 0-41
99-65
* Fourcroy's System, x. 26. f Mem. d'Arcueil, i. 23 and 46.
J The salts were phosphate, sulphate, muriate of soda ; phosphate of lime,
oxide of iron.
410 LIQUID PARTS OF ANIMALS.
Berzelius analyzed bile in 1808, and gave the result in the se-
cond volume of his Animal Chemistry* According to this ana-
lysis, the constituents of the bile are as follows :
Water, . . 908-4
Biliary matter, . . 80-0
Albumen, . ;. . 3-0
Soda, . . tt*i". 4-1
Phosphate of lime, . O'l
Common salt, . . 3 -4
Phosphates of soda and lime, . 1*0
1000-0 f
He afterwards made some corrections on his analysis, and in
his Traite de Chimie, (vii. 189), gives the constituents of bile as
follows :
Water, . . . . 904-4
Biliary matter, (including fat), lj;f ... . 80-0
Mucus of gall-bladder, . . ;r, 3-0
Extract of meat, common salt, and lactate of soda, .,^f 7-4
Soda, .... 4-1
Phosphates of soda and lime, trace of substance insoluble 1 , ,
in alcohol, ;;> . . /
1000-0
It is obvious that the biliary matter of Berzelius and the pi-
cromel of Thenard constitute one and the same substance.
Dr Prout analyzed the bile in the same way as Berzelius, and
obtained similar results.
Tiedemann and Gmelin published their work on digestion in
1825. They made a great many experiments on ox-bile, and
likewise on the bile of other animals. From ox-bile they extract-
ed no fewer than twenty-three different substances, which they
distinguished by the following names :
1. An odorous principle.
2. Cholesterin or biliary tallow.
3. Biliary resin.
4. Biliary asparagin or taurin.
5. Picromel.
* Djurkemie, ii. 48.
t Berzelius does not mention the animal whose bile this is an analysis of, I
presume it was ox-bile.
BILE. 411
6. Colouring matter.
7. A substance containing much azote, slightly soluble in wa-
ter ; insoluble in cold, but soluble in hot alcohol.
8. Gliadin ? insoluble in water, but soluble in hot alcohol.
9. Osmazome ? soluble in water and alcohol, precipitated by
infusion of nut-galls.
10. A substance emitting when heated a urinous smelL
11. Casein.
12. Mucus.
13. Bicarbonate of ammonia.
14 to 20. Margarate, oleate, acetate, cholate, bicarbonate,
phosphate, and sulphate of soda, (with some potash).
21. Common salt.
22. Phosphate of lime.
23. Water, amounting to 91*51 per cent.*
There can be no doubt that the taurin of Gmelin was formed
from the biliary matter of Berzelius during the processes to which
it was subjected.
Bile is a liquid of a greenish-yellow colour. Its taste is very
bitter, but at the same time sweetish, having some resemblance
to the taste of liquorice sugar. Its smell is weak, but peculiar
and disagreeable. It does not alter the colour of vegetable blues.
Its consistence varies very much ; sometimes it is a thin mucilage,
sometimes very viscid and glutinous. Sometimes it is transpa-
rent, and sometimes it contains a yellow matter, which precipi-
tates when the bile is diluted with water.
Its specific gravity varies, as is the case with all animal fluids.
According to Hartmann it is 1 *027 ;t according to Thenard 1 -026
at the temperature of 43°. Berzelius states the mean specific
gravity at 1*0254 When strongly agitated it lathers like soap.
It mixes with water in any proportion, and assumes a yellow co-
lour. But it refuses to unite with oil. Yet it dissolves soap rea-
dily, and is often employed to free cloth from greasy spots.
When distilled to dryness, it becomes at first slightly muddy ;
then it froths violently, and a colourless liquor passes into the
receiver, having a smell similar to that of bile, and slightly pre-
cipitated by diacetate of lead. The residue in the retort when
* Recherches, &c. i. 42. f HaUer's Physiol. vi. 546.
| Djurkemie, ii. 45.
LIQUID PARTS OF ANIMALS.
well dried amounts to one-eighth or one-ninth of the original
quantity of bile.
Ox-bile has been long used as a substitute for soap to remove
stains from carpets, woollen cloths, &c. On that account it was
considered by the iatro-chemists as a soap or a compound of an
animal oil and an alkali. The alkali was ascertained to be soda;
and this soda was, of course, united to an oily acid, which con-
verted it into soap. This view was considered as overturned by
the experiments of Thenard. Berzelius's analysis was not incoin -
patible with the soapy nature of bile ; though he does not appear
to have considered the liquid in that point of view.
It was shown by M. Demarcay in 1838 that the old opinion
of the soapy nature of bile, supported by Cadet, is, after all that
has been said to the contrary, the true one. He has proved that
the essential constituents of bile are soda, and an oily acid com-
bined with the soda, which he has distinguished by the name of
choleic acidy* and of which an account has been given in a pre-
vious part of this volume.f
We possesss but little information respecting the bile of birds.
Tiedemann and Gmelin found it very different in different species,
and even in those of the same species. Sometimes it was greenish-
blue, sometimes emerald green, and sometimes verdigris green.
In fowls and ducks it was so glutinous, that it could be drawn
into long threads, and it contained mucous clots. They even
made an analysis of the bile of a duck. They found the salts
the same as in ox-bile ; and it is probable, from their experi-
ments, that it consists essentially of choleate of soda, though no
experiments are stated from which the properties of the choleic
acid can be determined. J
According to Tiedemann and Gmelin, the bile contained in
the gall-bladder of the Rana temporaria amounted to only a few
drops. It was yellowish-green, transparent, and very liquid. Its
taste was sweetish and much less bitter than the bile of fishes.
When mixed with solution of potash, it becomes muddy, and
yellow flocks precipitate.
* Ann. de Chim. et de Phys. Ixvii. 177.
f It is not unlikely that, besides choleic acid, bile may contain some other oily
acid. At least, Dema^ay made no attempt to determine whether some other
acid was not present.
| Recheiches sur la Digestion, ii. 158.
CHYLE. 413
The gall-bladder of the Coluber natrix, according to the same
chemists, contained a gramme (15'433 grains) of bile, which
was grass-green, transparent, and very liquid.
Berzelius made some experiments upon the bile of the Python
amethystinus, a snake from Bengal, which died accidentally at
Stockholm.* It had a deep-green colour passing into yellow.
When partially evaporated, it left a transparent mass having the
same colour, soft, but very viscid, and completely soluble in
water. He found it to contain biliary matter, doubtless chole-
ates of potash and soda, colouring matter, a substance capable of
crystallizing, a substance analogous to salivin, albumen, fatty
acids, and certain salts.
Tiedemann and Gmelin analyzed the bile of several fishes, but
the facts ascertained do not seem of sufficient importance to be
detailed.
CHAPTER VII.
OF CHYLE.
OWING to the small size of the lacteals, and the consequent
difficulty of collecting their contents in any quantity, the proper-
ties of vhyle, as it is when just absorbed from the intestines, are
but imperfectly known. In the mammalia it is opaque and white
as milk : in birds and fishes it is nearly transparent and colour-
less.
MM. Emmert and Reuss, about the year 1808, made a set of
experiments on the chyle of the horse, which was published in 181 1
in the Annales de Chimie (Ixxx. 81.) They collected the chyle
from different parts of the thoracic duct. The chyle in the lacteals
was white like milk, while that in the thoracic duct was of a pale-
yellow colour. It had the consistence of serum of blood, a sa-
line taste, and a peculiar smell. It assumed a pink colour on ex-
posure to the air, resembling a mixture of milk with some drops
of blood. It coagulated when exposed to the air, but slowly and
imperfectly. We see, from these observations, imperfect as they
are, that chyle has considerable resemblance to blood. It coa-
gulates spontaneously like blood, and therefore contains a sub-
* Poggendorf s Annalen, xviii. 87.
414* LIQUID PARTS OF ANIMALS.
stance analogous to the globules of blood, though not red. The
uncoagulated portion coagulated by heat, and therefore contain-
ed albumen.
The chyle from the sublumbar branches of the thoracic duct
of horses was examined likewise by Emmert and Reuss, and also
by Vauquelin.* It was white and opaque like milk, and con-
tained a white and opaque coagulum. The liquid portion was
coagulated by heat, by acids, and by alcohol ; and therefore con-
tained albumen. There was also an alkali in it, as it restored
the blue colour of litmus-paper reddened by an acid. Hot alco-
hol dissolved a fatty matter from the coagulum. The portion
which coagulated spontaneously contained characters analogous
to those tifjSMm
Dr Marcet and Dr Prout examined, in 1815, the chyle of two
dogs, one of which had been fed entirely on vegetable food, the
other on animal food.f
Dr Marcet described the chyle of the dog fed on vegetable
food in the following terms : Soon after being collected it was
a semitransparent, inodorous, colourless fluid, having but a very
slight milky hue, like whey diluted with water. Within this
fluid there was a coagulum or globular matter, which was also
transparent and nearly colourless, having the appearance and
consistence of albumen ovi, or of those gelatinized transparent
clots of albuminous matter, which are sometimes secreted by in-
flamed surfaces. This mass had a faint pink hue, and minute red-
dish filaments were observed upon its surface. It did not, as Dr
Prout ascertained, affect litmus or turmeric paper, nor did it
coagulate milk. The coagulum/ when separated from the serum,
parted readily with its serosity or fluid portion, and was at length
reduced to a very small size. The specific gravity varied from
1O215 to 1-022. The portion of solid matter including salts
varied in different specimens of chyle from 4»8 to 7*8 per cent.
Both Dr Marcet and Dr Prout found the chyle of the dog
fed on animal food agreeing with that of the dog fed on vege-
table food, except that, instead of being nearly transparent and
colourless, it was white and opaque like cream. The coagulum
was also white and opaque, and had a more distinct pink hue,
with an appearance not unlike that of very minute blood-vessels.
The coagulum gradually yielded farther quantities of serous fluid,
* Ann. de Chim. Ixxxi. 113. f Annals of Philosophy, xiii. 12.
CHYLE. 415
till nothing remained but a small quantity of pulpy opaque
substance, in appearance somewbat similar to thick cream ; and
containing minute globules, besides the red particles already no-
ticed. The residue of the coagulum became quite putrid in
the course of three days, while that obtained from vegetable
chyle in a similar manner had not yet begun to undergo that
process. Dr Prout analyzed these two specimens of chyle, and
obtained the following results :
Vegetable food. Animal food.
Water, . . 93-6 . 89'2
Fibrin, . . 0-6 0-8
Incipient albumen ? . 4-6 . 4'7
Albumen with red colouring matter, 0-4 • 4*6
Sugar of milk ? . trace.
Oily matter, . trace. trace.
Salts, . . 0-8 0-7
100-0 100-0
Nearly the same modes of operating were adopted in the ana
lysis of both specimens.
The water was determined by evaporating a given weight of
chyle upon the water-bath,
The coagulum was repeatedly washed with cold water till it
ceased to give any thing to that liquid. The residue was consi-
dered asjibrin. The only peculiarity in this substance was that it
dissolved with greater difficulty in acetic acid than fibrin from
blood.
To the serous portion dilute acetic acid was added, and the
mixture was raised to the boiling point. A precipitate fell, which
was also thrown down by corrosive sublimate. It was not albu-
men nor casein. This is the substance called in the preceding
table incipient albumen.
After the preceding substance had been removed by filtration,
prussiate of potash was added to the acetic solution. A precipi-
tate fell, which was considered as albumen.
Dr Prout ascertained that the albumen in chyle coagulates
when heated to 149°, which is ten degrees lower than the coagu-
lating point of the albumen in the blood.
Leuret and Lassaigne examined the chyle from a variety of
animals, chiefly dogs and horses. They assure us that, whatever
416 LIQUID PARTS OF ANIMALS.
the nature of the food was, the constituents of the chyle were al-
ways the same. They constantly obtained fibrin, albumen,
fatty matter, soda, common salt, and phosphate of lime ; though
the proportions of these constituents vary much according to cir-
cumstances.*
Dr G. O. Rees subjected the chyle from the lacteal s of a young
ass, taken out immediately after death, to analysis and obtained,
Water, . ^902-37
Albuminous matter, 35-16
Fibrin, . 3-70
Alcoholic extractive, 3-32
Aqueous extractive, 12-33
Fatty matter, . 36-01
Salts, . 7-11
1000-00
The salts were alkaline chloride, sulphate and carbonate, tra-
ces of phosphate ; oxide of iron. The oxide of iron was found
in considerable quantity in the aqueous extractive matter.f
CHAPTER VIII.
OF LYMPH.
THE lymph is conveyed from all the cavities of the body by a
set of vessels called lymphatics, discovered by Olaus Rudbeck,
in the year 1651. The discovery was also claimed by Thomas
Bartholin. But it is now universally admitted that Rudbeck
had the priority. These vessels, called also absorbents, are trans-
parent, and their coats are very thin. They are very small, and
do not increase in size by the conflux of branches. Appended
to them are a number of nodular bodies called glands or gan-
glions. These bodies in the extremities are usually found at the
flexures of joints ; but in the cavities they are variously disposed.
When the vessels arrive at these glands, they become intimate-
ly connected with them, and seem to ramify through their interior.
It would be difficult to convey an accurate idea of the course
* Recherches, &c. p. 158. f phil- MaS- (3d series,) xviii. 156.
LYMPH. 41?
which these vessels take from the extremities to the thoracic duct
in which they terminate. But excellent plates of them were
published by Mascagni in 1790, to which the reader is referred
for a correct idea of their course.
These vessels convey away a liquor which is exhaled from all
the serous membranes of the body, in order to lubricate these
surfaces, and keep them in a state proper for performing their
respective functions in the living body. What the amount of
this liquid is we have no means of determining, but it is convey-
ed by the lymphatics from all the cavities where it is generated
and conducted by them to the thoracic duct, where it is mixed
with the chyle and conveyed along with it into the blood. When
the quantity of lymph secreted exceeds that carried off by the
lymphatics it accumulates in these cavities, and produces the
disease called dropsy.
According to M. Collard de Martigny, lymph scarcely flows
into the thoracic duct during the process of digestion, but it
does when that process is at an end. The flow increases and the
vessels become turgid by fasting ; but when abstinence is conti-
nued till death ensues, the lymphatics are destitute of lymph.*
Reuss and Emmertf examined the lymph of a horse in 1799.
It was transparent, and had a pale-yellow colour, with a slight
tint of green. When examined by a powerful microscope, no
globules nor any other substance of a determinate form could be
distinguished in it. It was a liquid apparently homogeneous,
without smell, but having a slight taste similar to that of the se-
rum of blood. In about a quarter of an hour after it was taken
out of the vessels, it coagulated into a colourless jelly, which
gradually contracted and swam in a yellowish liquid. This coa-
gulum was considered as similar to the fibrin of blood : 92 grains
of lymph yielded one grain of fibrin, weighed while moist ; so
that the quantity of dry fibrin in lymph cannot amount to j^th
part. The residual serum being evaporated to dryness left 3*25
per cent, of dry residue, consisting principally of albumen, which
remained undissolved when the dry residue was washed with
water. W,hen this water was evaporated crystals of common salt
were deposited.
Lymph from the neck of a horse was examined by Lassaigne
* Journ. de Physiologic, viii. 174. f Scherer's Journ. v. 691,
Dd
418 LIQUID PARTS OF ANIMALS.
in 1825.* It was transparent, yellowish, without smell, and had
a saline taste. It coagulated spontaneously both in vacuo and
when exposed to the air. The coagulura was colourless fibrin.
Lassaigne states the constituents of lymph to be,
Water, . Ut . 925-00
Fibrin, ..•»'.• qi»$jl ;i— - — : 3-30
Albumen, . . $ . 57 -36
Common salt, chloride of potassium, 1 14.34
Soda, phosphate of lime, . J
100-00
This analysis, though imperfect, shows a close resemblance be-
tween lymph and chyle.
Mr Brande in 1812 made a few observations on the lymph
taken from the thoracic duct of animals that had been kept for
twenty-four hours without food.f It was miscible with water in
every proportion, did not alter vegetable colours ; it was neither
coagulated by heat, nor acids, nor alcohol, but it was rendered
slightly turbid by the last reagent When evaporated to dry-
ness it leaves a very small residue, which changes violet-paper to
green. The ashes contained a minute portion of common salt,
but no iron.
Mr Brande does not inform us from what animal this lymph
had been obtained. It differed in its characters from the lymph
examined by Reuss and Eminert, and by Lassaigne.
In the winter of 1831-2, Professor Miiller of Bonn had an
opportunity of examining pure lymph. It issued from a small
wound in the back part of the foot of a young man. This wound
would not heal. When the back of the great toe behind the
wound was pressed, a quantity of clear liquid issued out, some-
times in a jet. This liquid was lymph. In about ten minutes
it deposited a coagulum of fibrin in a form resembling a spider's
web. The lymph, though clear and transparent, yet, when ex-
amined by the microscope, was found to contain numerous
colourless globules. They were smaller, and not so numerous as
the globules in the blood. Some of these globules united with
the coagulum ; but the greatest part remained suspended in the
liquid portion.
* See Berzelius's Traite de Chimie, vii. 128. f Phil. Trans. 1812, p. 96.
LYMPH. 419
The coagulum did not consist of globules, as is the case with
the crassamentum of the blood. It had originally been in solu-
tion in the liquid, while the globules were suspended in it. The
globules separated and contained in the coagulum might be seen
scattered through it, and these were much smaller than the glo-
bules that still remained in suspension in the liquid.
Professor Muller gives a method of obtaining pure lymph
from the frog. When the skin is removed from the thigh of a
large frog, and the muscles laid bare without wounding any
large blood-vessel, a clear, colourless, salt- tasted lymph flows
out. It contains ¥\ of fibrin. If the frog has fasted long no
lymph can be got by this process. The globules in the lymph
of the frog are exceedingly small. Lymph in the lymphatic
vessels is commonly colourless, in those of the spleen it is reddish.
We know little about the motion of the lymph. Muller describes
an organ which he considers as connected with that motion.*
A quantity of lymph from a wound after the removal of the
foot was collected and examined by MM. Marchand and Col-
berg.f About 1^ gramme was collected in twelve hours. Its spe-
cific gravity was 1O37. It gradually deposited a thin web of
fibrin, amounting to about half a per cent, of the lymph. The
opalescent liquid above it had a yellow colour, and the consist-
ence of almond oil. Its constituents, as determined by these
Chemists were,
Water, . . 96-926
Fibrin, . . 0-520
Albumen, . (K34
Osmazome and loss, . 0*312
Fat oil, |
Crystalline fat, /
Chloride of sodium,
Chloride of potassium,
Carbonate and lactate of potash,
Sulphate of lime, ,
Phosphate of lime,
• Oxide of iron,
lOO'OOO
* Poggendorf's Ann. xxv. 513. f Ibid, xliii. 625.
1-544
LIQUID PARTS OF ANIMALS.
A quantity of lymph, taken from the absorbents of a young
ass immediately after death, was analyzed by Dr G. O. Rees.
He states its constituents to be,
Water, . 965*36
Albuminous matter, * 12*00
Fibrin, . 1*20
Alcoholic extractive, > . 2-40
Aqueous extractive, . 13*19
Fatty matter, a trace.
Salts, <,:*>. 5-85
1000-00
The salts were alkaline chloride, sulphate, carbonate ; traces
.of a phosphate ; oxide of iron.*
As the liquid which collects in the cavities of the body during
dropsy is undoubtedly of a similar nature with lymph, being the
liquid which the lymphatics in ordinary health absorb, though
probably from the increased quantity it is more diluted with wa-
ter, some light may perhaps be thrown upon the nature of
lymph by stating the constituents of the liquor of dropsy as they
have been determined by chemical analysis.
1. Liquor of blisters. — This liquid is transparent and colour-
less when the blisters are natural. When they are raised arti-
ficially by the application of cantharides, the liquor has a yel-
lowish colour, and the smell of the blistering plaster. By Mar-
gueron's analysis, it is analogous to serum of blood, consisting
I*
of,
Water, . 78
Albumen, . 18
Common salt, . 2
Carbonate of soda, 1
Phosphate of soda, 1
100-t
2. Liquor of hydrocephalus internus. — This liquid, which was
limpid and colourless, was analyzed by M. Barruel, who ob-
tained,
* Phil. Mag. (3d series,) xviii. 156. f A"n. de Chim. xiv. 225.
LYMPH.
Water, . 990'0
Albumen, . 1 *5
Osmazorae, 0*5
Common salt, . 6 '5
Phosphate of soda, 0*5
Carbonate of soda, 1*0
1000-0*
3. Guttural ganglions of the horse. — The liquid in these gan-
glions was examined by Lassaigne,f and found to contain,
Fibrin, a great deal.
Coagulated albumen, a little.
Soluble albumen.
Traces of fatty matter.
Phosphate and carbonate of lime.
It was observed by M. Gaspard, that when men were obliged,
from want of proper food, to feed on grass and green herbs, ana-
sarca was the consequence. :f
4. Liquor of the pericardium. — This liquor, obtained from the
pericardium of a boy who died suddenly, was examined by Dr
Bostock.§ It had the colour and appearance of the serum of
blood. When evaporated to dryness it left a residuum amount-
ing to ^yth of its weight. When exposed to the heat of boiling
water it became opaque and thready. It was abundantly pre-
cipitated by corrosive sublimate before boiling, but after boiling
and filtering it was not affected by this reagent. Hence it evi-
dently contained albumen. It yielded,
Water, . 92-0
Albumen, . 5 '5
Mucus, . 2-0
Common salt, 0'5
100-0
5. 'Liquor from spina bifida. — This liquid also was examined
by Dr Bostock.|| It was slightly opaque, and did not alter ve-
getable blues. Heat increased its opacity, but did not coagulate
it It contained,
* Jour, de Physiol. i. 98. t Ibid. p. 391
+ ibid. p. 237. § Nicholson's Journal, xiv. 147.
II Nicholson's Jour. xiv. 145.
LIQUID PARTS OF ANIMALS.
Water, . 97'8
Common salt, 1*0
Albumen, '.. * 0-5
Mucus, . 0*5 1
Gelatin? ., 0-2 / Pr°P°rtlons conjectural
Lime, trace.
100-0
6. Liquor of asdtes. — This liquid obtained in the usual way
by tapping was examined by M. Dulong Junr.* It was clear
and limpid, had the consistence of white of egg, and frothed
when agitated. It restored the blue colour of reddened litmus-
paper. Potash and soda occasioned a slight smell of ammonia.
Heat and alcohol coagulated it completely. Its constituents
were,
Water, r f 70-38
Albumen, ; . • 29-00
Common salt, .% 0-28
Soda, . 0-14
Gelatin or altered albumen, 0'20
Ammonia, trace.
100-00
This liquid contained more albumen than the serum of blood.
Probably it was contained in a cyst, and a portion of its water had
been withdrawn by the absorbents.
7. Another liquid of asdtes. — This liquid, which exhibited some
remarkable characters, was examined by M. Coldefy-Dorly,
apothecary at Cressy.f
It was brown, very viscid, without smell and tasteless ; did not
alter vegetable blues. It held in suspension a great number of
brilliant crystals, which the viscosity of the liquid prevented from
subsiding. When heated it coagulated. Sulphuric, muriatic,
and especially nitric acid caused a copious precipitate. Alkalies
increased the intensity of the colour, and rendered the liquor
more fluid ; but did not disengage any ammonia. From 100
parts of it subjected to analysis, the following constituents were
obtained :
" Jour, de Pharmacie, xi. 140. f Ibid. p. 401.
LYMPH. 423
Albumen, . 4-80
Common salt, . 0*52
Chloride of calcium, 0-04
Uncrystallizable sugar, 0*24
Fatty matter, . 0-20
Mucus, . . 0-24
6-04
Besides traces of sulphur, muriatic acid, and a colouring matter
intimately united to albumen.
8. Another liquor of ascites. — This liquor was extracted by
tapping for the third time the abdomen of a female fourteen days
before her death. It was examined by M. Marchand.*
It was a yellow-coloured liquid, transparent, without smell,
and having a weak salt taste. Its constituents were,
Water, . 95-22
Albumen, . 2*38
Urea, . . -42
Carbonate of soda, . 0*21
Phosphate of soda, . 0-06
Common salt, . 0*82
Mucus and loss, * 0-89
Sulphate of soda, trace.
100-00
9. Liquor from the vertebral column of a horse. — This liquid
was analyzed by Lassaigne, who states its constituents to be,
Water, . 98-180
Osmazome, . 1 • 1 04
Albumen, »-LV:*< . 0-035
Common salt, . O'GIO
Carbonate of soda, 0-060
Phosphate of lime, 0'009
Carbonate of lime, trace.
99-998f
These analyses are, of course, imperfect. They show a cer-
tain analogy between these liquids and serum of blood ; but it
* Poggendorf s Annalen, xxxviii. 356. t Jour, de Physiologic, vii. 82.
LIQUID PARTS OF ANIMALS.
follows from them that not merely the ratios, but the constituents
themselves had been altered by disease.
CHAPTER IX.
OF MILK.
MILK is a fluid secreted by the female of all the animals be-
longing to the class of Mammalia., and intended evidently for
the nourishment of her offspring.
The milk of every animal possesses certain distinctive peculia-
rities, but the milk which, from time immemorial, has been
chiefly used by man as an article of food is that of the cow. It
will be proper, on that account, to give, in the first place, an ac-
count of that milk. We may afterwards point out the charac-
teristic distinctions between it and that of other animals.
We have only to open the Old Testament or the writings of
Homer, to be satisfied at how early a period the milk of the cow
was used as an article of food. Herodotus informs us that the
common drink of the Scythians in his time was the milk of mares.*
It appears from the same passage of Herodotus that the Scythians
were acquainted with the mode of making butter. And Hippo-
crates, whose era was not much later than that of Herodotus,
describes their process very clearly : " The Scythians," says he,
" pour the milk of their mares into wooden vessels, and shake it
violently. This causes it to foam, and the fat part, which is light,
rising to the surface, becomes what is called butter (/3o-j7ugov).
The heavy or thick part, which is below, being kneaded and pro-
perly prepared, is, after it has been dried, known by the name of
hippace (/T^axTj). The whey, or serum, remains in the middle, f
Hippocrates, as appears from this passage, was acquainted with
butter. He gives it in his writings the name of pickerion (TTIXS-
g/ov). This seems to have been the old Greek name for butter.
But it went out of use, and the term fiovrvgov came in its place.
There is no evidence that butter was known to the ancient
Hebrews. What is translated butter in the Septuagint, and that
translation has been adopted in our Bible, is admitted to have
meant cream, and not butter. It was known to the Greeks soon
* Melpomene, cap. 2. f De Morbis, lib. iv. p. 67. Edit. 1595.'
3
MILK. 425
after the time of Hippocrates, but that people do not seem to
have used it as an article of food. It is obvious, from what Pliny
says, that even in his time butter was but little used by the Ro-
mans. " It is surprising," says he, " that the barbarous nations
which live upon milk should for so many ages have been igno-
rant of or have despised cheese, thickening their milk into an
unpleasant acid matter and into fat butter.* Cheese seems to
have been known to the Greeks and Romans at an early period,
and to have been used by them as an article of food. It is cu-
rious that Aristotle never alludes to butter in any of his writings,
though he is very particular in his account of cheese.
Boerhaave considered milk as a natural emulsion, consisting of
an oil intimately mixed with a mucilaginous substance, f Neu-
mann considered it as analogous to chyle. He found that a pint
of cow's milk when evaporated to dryness left two ounces and two
drachms of residue ; but he found the milk of the same cow to
yield various proportions of dry residue at different times. He
gives a pretty minute description of butter, cheese, sugar of milk,
and whey, but takes no notice of the saline contents of that li-
quid, except that after combustion it leaves an alkaline ash.:f
M. Rouelle made a careful examination of the saline constitu-
ents of milk in 1772, but he obtained nothing but sugar of milk,
chloride of potassium, and a very minute quantity of carbonate
of potash. His results were published in the Journal de Mede-
cine for 1773.§
In 1790, an elaborate memoir, by Parmentier and Deyeux, on
the Physical and Chemical properties of the Milk of Woman, Cow,
Goat, Ass, Sheep, and Mare, was published. To the authors of this
memoir was awarded the prize offered by the Royal Medical So-
ciety of Paris for the best essay on the above subject. In this
paper we find the first attempt at a chemical analysis of milk. It
was necessarily imperfect, but it contained a great many import-
ant observations, which facilitated the labours of other chemists. ||
In the year 1804, Bouillon-Lagrange published a memoir on
milk and lactic acid;1[ Scheele had long before (in 1780) made
* Plinii, Natur. Hist. lib. xi. cap. 41.
f Boerhaave's Chemistry, ii. 62, Shaw's translation.
\ Neumann's Chemistry, p. 569.
§ See Macquer's Dictionnaire de Chimie, Art. Lait.
y See Journ. de Phys. xxxvii. 361 and 415. \ Ann. de Chim. 1. 272.
426 LIQUID PARTS OF ANIMALS.
experiments on lactic acid, and pointed out its peculiar nature.*
He had also made experiments on curd, and pointed out its ana-
logy to albumen. Bouillon-Lagrange made a pretty minute exa-
mination of the properties of curd, and endeavoured to prove
that lactic acid is nothing else than acetic acid mixed with chlo-
ride of potassium, a little iron, and an animal matter.
About the year 1805, Thenard published a paper on milk^ in
which he shows that butter may be separated from milk without
the access of air. He pointed out a mode of purifying butter by
fusion, and noticed some of its properties. Like Bouillon-La-
grange he considered lactic acid as merely acetic acid contami-
nated by animal matter. The same opinion had been advanced
by Fourcroy and Vauquelin.J
In 1808, Berzelius published the second volume of his Animal
Chemistry. § He analyzed cow's milk, and examined in detail
the properties of butter, curd, and whey. The constituents of
skimmed milk, according to his analysis, are,
Water, . . . ' . 92-875
Curd (not free from butter), . . . » 2-800
Sugar of milk, . \ . • 3 '500
Lactic acid and lactate of potash, r , - *' 0-600
Chloride of potassium, v .' . 0-170
Phosphate of potash, ;. > *; >rif, 0-025
Phosphate of lime and magnesia, with a trace of iron, 0-030
100-000
In 1830, an interesting paper was published by Braconnot on
casein, or the curd of milk, and on the new resources which it
opened to society. || He gives an account of the chemical pro-
perties of casein, and points out the various important uses to
which it may be applied. About the same time M. Macaire-
Princep made some experiments on the formation of butter.1" In
1832, Lassaigne published a number of analyses of the milk of
the cow before and after parturition ;** and in 1836 M. Peligot
gave a chemical analysis of the milk of the ass ;ff and in 1839 we
* Scheele's Essays, p. 265. f Nicholson's Journ. xii. 218.
J Mem. de Hnstitut, vi. 332. § Djurkemie, ii. 409.
|| Ann. de Chim. et de Phys. xliii. 337.
If Bibliotheque Univer. xliii. 379, or Poggendorf s Annalen, xix. 48.
** Ann. de Chim. et de Phys. xcix. 31. ft Ibid. Ixii. 432.
4
MILK. 427
have a historical account by Schill of the fermentation of milk
and the spirit that may be extracted from it. * A similar ac-
count had been given long before by Dr Guthrie.-|-
In 1839, an analysis of milk was made by M. Lecanu,J who
got,
Butter, . 36
Casein, . 56
Sugar of milk, ~\
Soluble salts, f 40
Extractive, J
Water, . 868
1000
and during the same year an elaborate chemical memoir on milk
was published by MM. O. Henri and Chevalier, § and another
by M. Simon. ||
The constituents of cow's milk in a normal state are, accord-
ding to the analysis of these chemists,
Casein, . 44*8
Butter, . 31-3
Sugar of milk, 47*7
Salts, . 6-0
Water, . 870-2
1000-Of
These proportions vary with the food. The following table shows
the variation when the cows were fed with carrots and with beet :
Carrots. Beet.
Casein, . 42-0 37-5
Butter, . 30-8 27-5
Sugar of milk, 53-0 59-5
Salts, . 7-5 6-8
Water, . 866-7 868-7
1000-0 1000-0**
Milk, as every body knows, is an opaque white-coloured fluid,
* Annalen der Pharmacie, xxxi. 152. f Edin. Trans. Vol. ii.
\ Jour, de Pharm. xxv. 201. § Ibid. p. 333, 401.
|| Ibid. p. 349. t Ibid. xxv. 340. ** Ibid. p. 342.
428 LIQUID PARTS OF ANIMALS.
having a slight but peculiar smell, and an agreeable sweetish
taste. It slightly reddens vegetable blues. Its boiling and
freezing points are nearly the same as those of water ; yet they
vary a few degrees in the milk of different animals.* Its speci-
fic gravity is greater than that of water and less than that of
blood ; but it varies so much even hi the milk from the same
animal, that it is impossible to give a correct mean. Brissonf
states the specific gravity of various milks as follows :
Woman's milk, , . 1-0203J
Mare's milk, . . . 1-0346
Ass's milk, . \ \;- 1 1-0355
Goat's milk, . * . 1*0341
Sheep's milk, v . 1-0409
Cow's milk, . ,r: . 1-0324
Clarified whey of cow's milk, 1-0193
Lassaigne examined the specific gravity of the milk at various
distances before and after parturition, and states the results as
follows :
42 days before parturition, ". 1-063
32, *t$ H '.•;'-:•• 1-062
21, . s > . intfo . 1-064
11, K*. . *'^ 1-040
Just after p arturition, ' ; >< 1 -039
4 days after, - . - . . 1-035
6, ' v . . 1-033
20, I1.'./! *$M 'V 1*040
21, -V-> -J- '• . 1-037
30, . 3 . . 10-38
The temperature at which these specific gravities were taken was
usually about 46°. The cow during the whole time was fed up-
on the same kind of food, namely, beet-root, hay, and straw.
We see that the specific gravity of the milk before parturition
is higher than after it. These specific gravities are all higher
than cow's milk, according to the statement of Brisson.
The first milk, or the milk which is given by the animal just
after parturition, is called colostrum. In Scotland it goes by the
* Jour, de Phys. xxxvii. 362.
f Lavoisier's Traite Elementaire de Chimie, ii. 587.
J Henri and Chevalier say that it varies from 1 -020 to 1 -025. See Jour,
de Pharm. xxv. 403.
MILK. 429
name of beist. The same term, I believe, is applied to it in En-
gland.
When milk is allowed to remain for some time at rest there
collects on its surface a thick unctuous, yellowish-coloured sub-
stance, known by the name of cream.
After the cream has separated, the milk which remains is much
thinner than before, and has a bluish white colour. If it be
heated to 100° and a little rennet (water digested with the inner
coat of a calf's stomach and preserved with salt,) be poured into
it, coagulation ensues. If the coagulum be broken the milk soon
separates into two distinct substances ; a solid white part known
by the name of curd, and a fluid portion called whey. Thus
milk is easily separated into three distinct substances, namely,
cream, curd, and whey.
1. Cream is a semiliquid of a yellow colour, and its consistence
increases gradually by exposure to the atmosphere. In three
or four days it becomes so thick that the vessel containing it may
be inverted without risking any loss. In eight or ten days more
its surface is covered over with mucors and byssi, and it has no
longer the flavour of cream but of very fat cheese.* In this
state it constitutes what in this country is called cream cheese.
The quantity of cream yielded by milk varies not only in dif-
ferent animals, but in the same animal at different times. The
following table shows the ratio between the bulks of cream and
whey from the same cow, (fed on beet-root, hay, and straw,) at
different periods before and after parturition, as determined by
Lassaigne :f
Volume of Volume of Water
cream. whey. per cent.
42 days before parturition, 200 . 800 . 78-4
32 ditto, . 200 . 800 . 78-2
21 ditto, . 200 . 800 . 78-1
11 ditto, . 200 . 800 . 78-8
Just after parturition, 200 . 800 . 78-2
4' days after ditto, 200 . 800 . 79.8
6 ditto, . 188 . 812 . 82-0
20 ditto, . 78 . 922 . 89-0
21 ditto, . 59 . 941 . 88-0
30 ditto, . 64 . 936 . 90-0
* Jour, de Phys. xxxvii. 372. f Ann. de Chim. et de Phys. xlix. 35.
430 LIQUID PARTS OF ANIMALS.
In a third column is inserted the weight of water contained in
100 parts of the respective milks.
Cream consists of a peculiar oily matter mixed with curd and
whey, and the substances held in solution in the whey. When
agitated for some time it separates into two portions, namely, a
solid yellow substance called butter, and a liquid portion contain-
ing the greatest part of the curd and whey. This liquid is cal-
led butter-milk. The process itself is called churning.
The formation of butter goes on equally well whether the ac-
cess of air be admitted or precluded. Macaire Princep has as-
certained by experiment, that no oxygen is absorbed from the at-
mosphere during the process of churning. This indeed has long
before been shown by Young* and by Thenard.f
In some cases it is said that there is an extrication of gas dur-
ing the churning of butter, and it has been inferred that this gas
is carbonic acid. But the fact has not been established in a sa-
tisfactory manner. Dr Young affirms, that during churning
there is an increase of temperature amounting to 4 degrees.
Cream, according to the analysis of Berzelius, consists of,
Butter, ' 4-5
Curd, i;- 3-5
Whey, 92-0
100-0
but it varies so much in the proportion of its constituents that
such analyses are of very little value.
The appearance and characters of butter are so universally
known that it is needless to describe it. In its usual state it con-
tains about Jth of its weight of substances contained in butter-
milk. To separate the butter from these substances it is to be
put into a cylindrical glass, and raised to a temperature which
must not be higher than 140°. The butter melts and swims up-
on the surface under the form of an oil, while the butter-milk is
collected in the lower part of the vessel. When the butter oil
has become clear it is to be poured into another vessel contain-
ing water heated to 1 04°, with which it is to be well-agitated, in
order to separate every thing from it that is soluble in that li-
quid. When the mixture is left at rest the butter -oil collects on
the surface, and when the water cools concretes into solid butter.
* Young de Lacte, p. 15. f Nicholson's Journal, xii. 218.
MILK. 431
Thus purified butter is a white solid substance like tallow.
Its yellow colour, when it has it, is owing to the food on which
the cow was fed. According to Chevreul, melted butter may
be cooled down to 80° before it congeals. The temperature
then suddenly rises to 90°, and continues at that point till the
solidification is completed.*
100 parts of alcohol of 0.822 dissolves 346 of butter. But-
ter is very easily saponified, requiring only 8 parts of potash ley
to saponify 20 parts of it. 100 parts of cow's milk butter when
thus saponified furnish 88-5 parts of fixed solid oily acids. This
acid matter contains 11-85 of glycerin, a little stearic acid, and
three volatile oily acids, f
Butter is composed of three kinds of fatty matter, namely, stea-
rin, elain, and a fatty matter from which the three volatile oily
acids are formed. To this last substance Chevreul, to whom we
owe all the facts here stated, has given the name of butyrin. The
relative proportions of these three fatty matters may vary accord-
ing to circumstances. This is the reason why butter varies so
much in its degree of consistence. Braconnot obtained by ex-
pression between 40 and 65 per cent, of stearin. :f According to
Chevreul, who separated it by crystallization from its solution in
alcohol, it is crystalline, and whiter and more brilliant than stea-
rin from ox tallow. It melts at 135°. 5 according to Braconnot.
According to Chevreul, it melts at 111°, and 100 parts of alco-
hol of 0-822 dissolve only 1-45 of this stearin. 100 parts of it,
when saponified, gave 94-5 of fatty acids fusible at 111°, and 7*2
of glycerin.
The elain of butter cannot be completely freed from butyrin,
nor the butyrin from elain. Chevreul employed the following
method to separate them : Purified butter was kept for a long
time between 61° and 66° of temperature. At that temperature
the elain and butyrin are liquid, while the solid stearin unites to-
gether by degrees, so that the liquid portion may be decanted
off. This liquid portion is an oil having the specific gravity of
0-922 at 66°. 100 parts of boiling alcohol of 0-822 dissolve 6
parts, of it. Upon this oil its own bulk of absolute alcohol was
poured, and the mixture was left for twenty- four hours, being
frequently agitated during that time, and the temperature was
* Chevreul sur les Corps Gras, p. 273. f
Ann. de Chim. xciii. 227.
LIQUID PARTS OF ANIMALS.
66°. The alcohol being decanted off and distilled over the wa-
ter-bath, left an oil which had an acid reaction, and the smell of
butter. This oil was butyrin, mixed with a little elain. The
acid reaction was owing to the property which alcohol has of par-
tially decomposing the butyrin and developing a portion of the
volatile acids which it furnishes, They may be removed by di-
gesting the butyrin with a mixture of water and magnesia. A
salt of magnesia soluble in water is formed, and the butyrin be-
comes neutral.
Butyrin in this state is an oil, sometimes yellow, sometimes
colourless. It has the taste and smell of butter, and becomes
solid when cooled down to 32°. It is miscible in all proportions
with boiling alcohol of 0-822. According to Chevreul, a mix-
ture of 2 parts butyrin and 10 parts alcohol becomes muddy on
cooling, while a mixture of 12 parts butyrin and 10 parts alco-
hol retains its transparency. The alcoholic solution becomes
always acid, and the more so the longer the digestion continues.
Butyrin is easily saponified. The fatty acids evolved by this pro-
cess begin to solidify at 90°, but do not become quite solid till
cooled down to 63°.
When the elain from butter is digested for a long time in ab-
solute alcohol, the butyrin dissolved becomes more and more
charged with elain as the process advances. If we digest it three
times successively with twice its weight of absolute alcohol, the
remaining elain which separates from the last portion of alcohol
as it cools is as free from butyrin as it can be made by this pro-
cess. It is not the least acid while the alcoholic solution red-
dens litmus. The specific gravity of this elain is 0-92 at 66°.
Alcohol of 0-822 dissolves only four-fifths of a per cent, of it
These three constituents of butter, namely, stearin, elain, and
butyrin, are all analogous to salts, being combinations of certain
oily acids and glycerin.
When butter is saponified by means of potash, or rather when
the liquid portion of butter is treated in this way, and the soap is
afterwards decomposed by adding a quantity of tartar ic acid suf-
ficient to convert the potash into bitartrate, the oily acids are
disengaged. The fatty acids are now washed with water, and
the water is distilled. The three peculiar acids of butter pass
over with the water into the receiver. These acids are the bu-
tyric, the caproic, and the capric. An account of these acids
MILK. 433
and of the method of separating them from each other, has been
given in a preceding volume of this work.*
The composition of these three acids, according to the analy-
sis of Chevreul, is as follows :
Butyric. Caproic. Capric.
Carbon, . 62-82 . 68-33 . 74-00
Hydrogen, 7'01 . 9-00 . 9-75
Oxygen, . 30-17 . 22-67 . 16-25
100-00 100-00 100-00
From the experiments of Chevreul it would appear that the ato-
mic weight of butyric acid is 9*625, that of caproic acid 13-25,
and that of capric acid 18-25. Hence the constituents of these
acids should be,
Butyric acid, C8 H5 O3 = 9-625
Caproic acid, C12 H10 O3 =13-25
Capric acid, C18 H14 O3 = 18-25
But new and careful analyses would be necessary before we could
consider these numbers as established.
2. When milk freed from cream is heated to 110°, or a little
higher, and mixed with a little rennet, it coagulates and gradual-
ly separates into a solid white matter called curd, and a liquid
portion distinguished by the name of whey.
Curd when in a state of purity is distinguished by the name
of casein. The mode of procuring it in a state of purity and its
properties have been given in a preceding chapter of this vo-
lume. Casein has many properties in common with the albu-
men of blood, and like albumen may be obtained in two states,
namely, uncoagulated, when it is soluble in water, and coagulated
when it is insoluble in that liquid. It is precipitated from its
aqueous solution by acetic acid, which is not the case with albu-
men. It is coagulated by a boiling heat, but slowly ; separating
in films which collect upon the surface of the liquid.
Qoagulated casein subjected to pressure to free it from the
whey constitutes cheese. If cheese consist of nothing but casein,
it has a bluish white colour, is very hard, almost like horn, and
is quite insipid. Good cheese is always made from milk still re-
taining its cream, and in Stilton, which is one of the richest of
the English cheeses, the milk is not only allowed to retain its na-
tural quantity of cream, but an additional quantity is added.
* See Chemistry of Inorganic Bodies, ii. 132.
E e
434 LIQUID PARTS OF ANIMALS.
It is impossible to state the proportion of casein which exists
in milk, because it varies so much, not only in the milk of dif-
ferent animals, but also in that of the same animal at different
times. According to Berzelius 100 parts of skimmed-milk which
he analyzed contained 2-8 of casein.
Lassaigne made a curious remark respecting the milk of a cow,
which he examined at ten different periods ; four of these before par-
turition and six after it. The milk examined during the first three
of these periods, namely, forty- two days, thirty- two days, and twen-
ty-one days before parturition, contained no casein at all, but in
place of it albumen. The milks examined eleven days before and
just after parturition contained both albumen and casein ; the milks
examined four days, six days, twenty days, twenty-one days, and
thirty days after parturition, contained casein and no albumen.*
It would have been of importance had Lassaigne informed us of
the method which he followed to distinguish casein from albu-
men, and to separate them from each other when they existed to-
gether in milk.
3. Whey, after being filtered to separate a quantity of curd,
which usually floats through it, is a thin pellucid fluid of a yel-
lowish green colour and an agreeable and sweetish taste, in which
the flavour of milk may be distinguished. Almost the whole
curd may be separated by keeping the whey for some time at a
boiling temperature. A thick white scum gathers on the surface,
known in Scotland by the name ofjftoat whey. When this scum,
which consists of the curdy part, is carefully separated, the whey,
after being left at rest for some hours to give the remainder of
the curd time to separate, is quite transparent, and much less
coloured than before. It still retains its sweet taste, but much
of the milky flavour is dissipated. If it be now evaporated over
the steam bath it deposits a number of crystals of sugar of milk.
Towards the end of the evaporation some crystals of chloride of
potassium and some of common salt, make their appearance.f
According to Scheele it contains also a little phosphate of lime,
which may be precipitated by ammonia. :f
Schwarz found that 1000 parts of cow's milk left 3-697 of
ashes, composed of
* Ann. de Chim. et de Phys. xlix. 35.
" f Parmentier, Jour, de Phys. xxxvii. 417.
| Scheele's Essays, ii. 61.
MILK. 435
Phosphate of lime,
Phosphate of magnesia,
Phosphate of iron,
Phosphate of soda,
Chloride of potassium,
Soda, combined with lactic acid,
3-697*
Lassaigne observed that milk from the cow forty-two days
thirty-two days, and twenty-one days before parturition contain-
ed no sugar of milk and no lactic acid, but a sensible quantity of
uncombined soda. In short, it bore a close resemblance to the
albumen of blood. While milk from the same cow eleven days
before parturition and always after it, contained free lactic acid
and sugar of milk but no free soda,f It would appear from this
and other observations of Lassaigne already noticed, that the
milk of the cow is at first very similar to the serum of blood, and
that the casein, sugar of milk, and lactic acid, to which it owes
much of its distinguishing characters, begins first to make their
appearance in it about eleven days before parturition.
The experiments of Fourcroy and Vauquelin, Thenard, Bou-
illon Lagrange, and Berzelius, have added considerably to our
knowledge of the constituents of whey. The sugar of milk con-
stitutes at an average about 3*5 per cent, of the whey ; while the
saline ingredients do not exceed 0*22 or two-ninths of a per cent.
The water of course constitutes about 96'3 in the hundred parts.
The saline contents of milk are, chloride of potassium, chloride
of sodium, phosphate of lime, of magnesia, and a trace of phos-
phate of iron, acetate of potash, lactate of potash, lactic acid, and
a trace of lactate of iron.
The colostrum, or beist milk of the cow, has a pretty deep-yel-
low colour with a tint of green. It contains a much greater pro-
portion of ricottin, and a smaller of casein than milk in its ordi-
nary state, and about six days after parturition elapse before the
milk contains the normal quantity of these two substances. The
colostruih when churned gives a very yellow butter which, when
heated, emits a smell similar to that of the white of egg. From
the observations of Parmentier and Deyeux, it would appear that
* Schweigger's Jour. viii. 271. t Ann. de Chim. et de Phys. xlix, 35,
436 LIQUID PARTS OF ANIMALS.
the cream does not separate from the colostrum so easily as from
ordinary milk. For after having removed the cream, a new por-
tion gradually collected on the surface of the milk. Butter
made from this second cream was not so yellow as that from the
first. When the colostrum is heated it coagulates like albumen.
The colostrum of the cow, the ass, and goat was analyzed by
Henri and Chevalier.* The result was as follows :
Cow. Ass. Goat.
Casein, . 150-7 116-0 245
Mucus, . 20-0 7-0 30
Sugar of milk, . trace. 43-0 32
Butter, . 26-0 5-6 52
Water, , „;> 803-3 828-4 641
1000-0 1000-0 1000
The opinion of medical men is, that the colostrum possesses
purgative properties, and that it is intended to free the bowels of
the new-born animal from the meconium with which they are
partly filled at the time of birth.
Milk is one of the few animal substances which may be made
to undergo the vinous fermentation, and to afford a liquid re-
sembling beer, from which alcohol may be separated by distilla-
tion. For this property it is indebted to the sugar of milk which
it contains, and which, like common sugar and sugar of grapes,
is susceptible of being decomposed into alcohol and carbonic acid.
The method of fermenting milk appears to have been discovered
by the Tartars, who obtain all their spirituous liquors from mare's
milk. The process followed by them is very simple : The milk
is allowed to become sour, it is then raised to the requisite tem-
perature. In summer the fermentation begins immediately, and
in twenty-four hours the liquid is converted into an intoxicating
liquor, to which the Tartars give the name of koumiss or kumysz.
In winter the process lasts two or three days, and the koumiss
may be kept for two or three months without losing any of its
good qualities. It has then an acid, and at the same time a sweet
taste, and possesses intoxicating qualities.
An account of the preparation and medical uses of koumiss
was published by Dr Guthrie in the second volume of the Trans-
actions of the Royal Society of Edinburgh. Indeed some ac-
* Jour, de Pharm. xxv. 348.
MILK. 437
count of it, with a receipt for making it, was inserted by Dr
Grieve in the first volume of these Transactions. A little very sour
milk is added to the mare's milk that is to be con verted into koumiss,
and the whole milk must be frequently and thoroughly agitated
several times during the process. The koumiss must always be well
agitated just before it is to be used. The Tartars consider this
liquid as highly nutritive and medicinal. There is an elaborate
history of this liquid, together with a set of experiments on the
fermentation of sugar of milk, by M. Schill, in the thirty-first vo-
lume of Liebig's Annalen der Pharmacie, (page 152.) Many
chemists had failed in their attempts to ferment milk and obtain
alcohol from it. Schill, however, succeeded. I have been in-
formed by the late Sir John Sinclair that koumiss is made both
in Orkney and Shetland nearly in the same way as in Tartary.
Of course, they will use cow's milk in these islands instead of
mare's milk.
From the experiments of numerous chemists it had been con-
cluded that sugar of milk is incapable of fermenting, and of
course of yielding alcohol. But Scheele had long ago observed
that milk ferments, and gives out a great deal of carbonic acid
gas.* And Schill found by experiment, that 100 parts of su-
gar of milk by fermentation may be made to yield 36*101 of ab-
solute alcohol, f
A set of experiments was made by MM. Boussingault and
Le Bel, to determine the effect of various kinds of food upon
the quantity and quality of the milk given by cows4 They have
not given satisfactory results. Because the quantity of milk di-
minishes in proportion as the time after calving increases. They
deserve a place, however, as giving the quantity and quality of
the milk of the same cow during a period of 302 days.
Scheele's Opuscula, ii. 66. f Annalen der Pharm. xxxi. 171,
Ann. de Chim. et de Phys. Ixxi. 65.
438 LIQUID PARTS OF ANIMALS.
Composition of the milk.
.5
i!
o S>j5 3 -| £co j? •§ 2
I is Is •**•* 3 I
?/" a "s1^ M-e
I
M
21-6
FIRST SERIES.
potatoes, hay, 15-1
2-6
3-6
0-3
78-4
13
1-65
—
ditto,
—
—
—
—
—
24
2-33
112
hay, clover, 30
3-5
4-5
0.2
88-8
35
2-64
13-1
clover,
3-1
5-6
4-2
03
869
200
1-23
12-3
hay,
3-0
4-5
4-7
0-1
87-7
207
1-32
12-4
turnips,
3-0
4-2
50
0-2
87-6
215
1-23
12-9
beet,
34
4-0
5-3
0-2
87-1
229
1-09
13-5
potatoes,
34
4-0
5-9
0-2
86-5
240
0-78
—
hay,
—
—
—
—
—
270
075
—
potatoes,
—
—
—
—
—
290
0-77
12-5
Jerusalem
choke,
arti.3.8
35
5-5
0-2
87-5
302
062
13-2
hay and oil
.cake,3-4
3-6
6-0
0-2
86-8
SECOND SERIES.
176
2-05
13-5
potatoes, hay, 5-3
4-8
5-1
0-3
86-5
182
1-96
128
hay, clover, 4-0
4-5
4-0
0-3
87-2
193
2-16
11-2
clover, . 4-0
2-2
4-7
0-3
88-8
204
1-72
12-6
clover in blossom,3-7
3*5
5-2
0-2
87-4
The most remarkable circumstance in this table is the small
quantity of milk given by the French cows subjected to experi-
ment. It is no uncommon thing for a good Ayrshire cow to
give 4 J imperial gallons in 24 hours. The greatest quantity in
the above table is 2 '64 gallons : not much more than the half of
4^ gallons.
The milk of the other mammalia, so far as has been examined,
consists nearly of the same ingredients as cow's milk ; but there
is a great difference in their proportions.
1. Woman's milk is thinner, more transparent, and much
sweeter than cow's milk. When left at rest a cream collects on the
surface, which has a whiter colour, and is more transparent than
cow's milk cream. The creamed milk is thin, and has rather the
appearance of whey with a bluish white colour, than of skimmed
milk.
It was stated by Parmentier and Deyeux, that this cream did
not yield butter. But Pleischl showed in 1821, that this was a
mistake, and that butter might be obtained from woman's milk as
well as from that of the cow.* Indeed Stipriaan, Luiscius, and
* Schweigger's Jour, xxxii. 124.
MILK. 439
Dr Bondt, proved as early as 1787, that butter could be obtain-
ed from woman's milk.*
None of the methods by which cow's milk is coagulated suc-
ceed in producing the coagulation of woman's milk.f Meggen-
hoffer found that while cold, neither muriatic acid, acetic acid,
acetate of lead, perchloride of iron, sulphate of copper, nor
corrosive sublimate caused it to coagulate ; but coagula-
tion was produced if the milk was warm. Sometimes, though
but seldom, alcohol caused it to coagulate. The same remark
applies to nitrate of silver. In 20 trials, sulphate of iron caused
the coagulation of about one-half. Protochloride of tin, acetate
of lead, protonitrate of mercury, and tincture of nut-galls had a
similar action to nitrate of silver. All these specimens of wo-
man's milk reddened litmus-paper.:]:
Woman's milk, according to Meggenhoffer, contains from 1 1
to 12 J per cent, of solid matter, and the quantity is greater a
considerable time after parturition than soon after it. By di-
gesting the solid matter of milk in alcohol Meggenhoffer obtain-
ed a butter which melted at 88° ; and the stearin deposited from
the alcohol as it cooled melted at 95°. This butter agrees, there-
fore, with that from cow's milk.
The characteristic property of woman's milk is, that the casein
forms soluble compounds with the acids, so -that we cannot throw
it down by their means. But this casein may be coagulated by
rennet. It does not concrete into a mass as in cow's milk, but
appears in isolated flocks. The mean quantity of casein in this
milk is between 2£ and 3 per cent. The following table ex-
hibits the result of the analysis by Meggenhoffer, of three differ-
ent specimens of milk from different women :
1. 2. 3.
Alcoholic extract, with butter, lac-^\
tic acid, and lactates, common salt, V 9-13 8*81 17*12
and a little sugar of milk,
Aqueous extracts, sugar of milk, and )
salts, ." . /
Casein, coagulated by rennet, . 2-41 1-47 2-88
Water, 87-25 88-35 78-93
99-93 99-92 99.81
* Crell's Anrialen, 1794, 76. f Clarke, Irish Trans, ii, 175,
\ Gmelin's Handbuch der Theor. Chimie, ii. 1402-.
440 LIQUID PARTS OF ANIMALS.
Payen* has given the following results of the analysis of wo-
man's milk from three several women :
1. 2. 3.
Fat, melting at 75°, . 5-16 5-20 5-18
Sugar of milk, soluble salts with trace 1 K/, £ 7-Q3 7-86
of animal matter, . /
Casein and insoluble salts, . 0-18 O25 0-24
Water, te«) A:* . 86-00 85-60 85-80f
98-96 98-98 99-08
Solid matter in the milk, . 13- 13-4 13-3
The constituents of woman's milk in its normal state, accord-
ing to the analysis of Henri and Chevalier are,
Casein, *>:;- 15*2
Butter, . 35'5
Sugar of milk, 65-0
Salts, . 4-5
Water, . 879-8
1000-Ot
According to Schubler most of the casein in woman's milk is
in the state of ricottin. But this remark does not quite accord
with the experiments of Meggenhoffer.
According to the experiments of Schwarz, 1000 parts of wo-
man's milk leave an ash when burnt, weighing 4*407 : and com-
posed of,
Phosphate of lime, • 2-5
Phosphate of magnesia, 0-5
Phosphate of iron, . 0*007
Phosphate of soda, . 0-4
Chloride of potassium, 0-7
Soda combined with lactic acid, 0-3
4-407§
2. Ass's milk has a strong resemblance to human milk. It
has nearly the same colour, smell, and consistence. When at
* Jour. Chim. Med. iv. 118.
f It is obvious that most of the casein remained in solution, and was confound-
ed with the sugar of milk, &c. obtained by evaporating the whey.
| Jour, de Pharm. xxv. 340. § Schweigger's Jour. viii. 271.
MILK. 441
rest a cream collects on its surface : but by no means in such
quantity as in woman's milk. This cream, by very long agitation,
yields a butter which is always soft, white, and tasteless ; and
what is singular, readily mixes with the butter milk ; but it may
be again separated by agitation, while the vessel which contains
it is plunged in cold water. Creamed ass's milk is thin, and
has an agreeable sweetish taste. Alcohol and acids separate from
it a little curd, which has but a small degree of consistence.
The serum yields sugar of milk and chloride of calcium.*
According to the experiments of Stipriaan, Luiscius and
Bondt, ass's milk yields at an average 2*9 per cent, of cream,
2*3 of casein, and 4*5 of sugar of milk. It undergoes very rea-
dily the vinous fermentation.f They found the specific gravity
of ass's milk 1'023.
In 1836, M. Peligot published some interesting experiments on
ass's milk. The object which he had in view was, if possible,
to discover whether the medicinal properties ascribed to this
milk might not be accounted for by some variation in its solid
constituents from that of the milk of other animals.:]: Its speci-
fic gravity varies from 1*030 to 1*035, being nearly the same as
that of cow's milk, yet it contains less solid matter. But cow's
milk contains more cream, which counteracts the effect of its so-
lid contents.
The mean composition of ass's milk, according to Peligot, is,
C Butter, . 1-29
Solid matters, 9 -53 -J Sugar of milk, 6-29
(.Casein, . 1-95
Water, . 90-47
9-53
100-
It contains more sugar of milk than cow's milk, and to this he
ascribes its medicinal properties.
It was found that the proportion of solid matter varied ac-
cording to the food by which the ass was nourished. The fol-
lowing are the results :
1. An ass fed during a month on carrots yielded a milk com-
posed of,
* Parmentier and Deyeux, Jour, de Phys. xxxvii. 423.
t Crell's Annalen, 1794, ii. 266.
\ Ann. de Chim. et de Pbys, Ixii. 432.
442 LIQUID PARTS OF ANIMALS.
r Butter, . 1-26
Solid matters, 8*89 •] Sugar of milk, 6-02
t Casein, . 1*62
Water, . 91-11
8-89
100-
2. The same ass fed for a fortnight on beet-root The milk
gave,
r Butter, . 1*39
Solid matters, 10-23 -j Sugar, . 6-51
1 Casein, . 2-33
Water, irr.ll 89-77
10-23
1000-00
3. The same ass fed for a month on pounded oats and dry
lucerne gave a milk of,
f Butter, rtotfr 1'40
Solid matters, 9-37 •] Sugar, Hi^ 6-42
(.Casein, \ vj'*" 1-55
Water, \ ^k 90-63
9-37
100-
4. The same ass fed for a fortnight on potatoes yielded a milk
composed of,
j Butter, f: . v 1-39
Solid matters, . 9-29 J Sugar, W!J«B 6-70
I Casein, *$ 1-20
Water, , 90-71
9-29
From these experiments it would seem that the most nourishing
food was beet-root, the next oats and lucerne, next potatoes, and
carrot the least nourishing of all. The quantity of milk was
proportional to the nourishment yielded by the food.
Beet-root gave && 1-5 kylogrammes of milk.
Oats and lucerne, 1-5
Potatoes, .siojr GO/;:.? 1-28
Carrots, . . 1-0
The longer the milk remains in the udder of the ass after milk-
ing before it be milked again, the less solid matter does the milk
contain, as will appear from the following table :
MILK.
443
Ill
Butter,
Sugar,
Casein,
Solid matters,
Water,
1£ hour..
After 6 hours. After 24 hours.
1-55
1-40
1-23
6-65
6-40
6-33
3-46
1-55
1-01
11-66
88-34
9-37
90-63
8-57
91-43
100- 100- 100-
When milk is examined at the beginning, middle, and end of
the same milking, the last drawn milk is the richest. This will
appear from the following table :
First drawn.
Butter, . 0-96
Sugar, . 6-50
Casein, . 1-76
End.
1-52
6-45
2-95
Solid matters,
Water,
9-22
90-78
10-45
89-55
10-94
89'66
100- 100- 100-
M. Peligot found that when iodide of potassium, common salt,
or bicarbonate of soda was mixed with the food of the ass, the
presence of these substances in the milk became sensible.
Henri and Chevalier state the constituents of ass's milk in
its normal state to be,
Casein, . 18-2
Butter, • 1-1
Sugar of milk, . 60-8
Salts, . 3-4
Water, • . 916-5
1000-0*
'Ass's milk, after the animal had undergone great fatigue,
yielded,
» Jour, de Pharm, xxv. 340,
444 LIQUID PARTS OF ANIMALS.
Casein, . 11-2
Butter, . 1-3
Sugar of milk, 59-0
Salts, . . 6-1
Water, . 922-4
1000-0 *
3. Mare's milk is thinner than that of the cow, but scarcely so
thin as woman's milk. Parmentier and Deyeux did not succeed
in obtaining butter from it by churning. But we know from
Herodotus that the ancient Scythians made butter from that
milk, several centuries before the commencement of the Christ-
ian era. Its specific gravity is from 1-045 to 1-035, as deter-
mined by Stipriaan, Luiscius, and D. Bondt.-f- The creamed
milk coagulates just as cow's milk, but the curd is not so abun-
dant. The whey contains sugar of milk, sulphate of lime, and
chloride of calcium.^ It readily ferments, and is converted by
the Tartars into koumiss.
According to Luiscius and Bondt, mare's milk contains
Casein, lV^ 16-2
Butter, « .^ trace.
Sugar, . 87-5
Salts and water, 896-3
1000-0§
M. Henri, Senior, in 1830 examined a little milk from the
udder of a foal only four days old. Its specific gravity was 1 -002.
It threw up no cream ; but when heated, was concreted and di-
vided into casein and serum. It yielded,
Fatty matter, . 1-
Casein, . • . 0'5
Serum, .-«' . 28-5
30-0||
4. Goafs milk, if we except its consistency, which is greater,
does not differ much from cow's milk. It throws up abundance
of cream, from which butter is easily extracted. The creamed
* Jour, de Pharm. xxv. p. 346. f Ibid. p. 347.
\ Parmentier and Deyeux ; Jour, de Phys. xxxvii. 428.
§ Crell'g Annalen, 1794, ii. 352. || Jour, de Pharm acie,xvi. 418.
MILK. 445
milk coagulates just as cow's milk does ; but yields a greater
quantity of curd. From the whey was extracted sugar of milk,
chloride of calcium, and common salt.*
Payen extracted from goat's milk,
Butter, . . 4-08
Casein and insoluble salts, . 4*52
Sugar of milk and soluble salts, 5*86
Water, . . 85-50
99-96 f
Stipriaan, Luiscius, and Bondt obtained,
Cream 7*5 per cent., yielding of butter 4-56 per cent. ; 9'12
per cent, of casein, and 4-38 of sugar of milk. J
Henri and Chevalier state the constituents of normal goat's
milk to be,
Casein, . 40'2
Butter, . . 33-2
Sugar of milk, . 52 '8
Salts, . . 5-8
Water, . 868-0
1000-0§
5. EwJs milk resembles very closely that of the cow. Its spe-
cific gravity was found by Stipriaan, Luiscius, and Bondt, to
be 1-035. Its cream is rather more abundant than from cow's
milk, and it yields a butter which never acquires the consistence
of common butter. Its curd has a fat and viscid appearance.
Normal ewe milk, according to the analysis of Henri and Che-
valier, is composed of,
Casein, . . 45 '0
Butter, . 42-0
Sugar of milk, . . 50-0
Salts, . . 6-8
Water, . . 856-2
1000-OH
* Parmentier and Deyeux, Jour, de Phys. xxxvii. 425.
f Jour. Chim. Med. iv. 118.
\ Crell's Annalen, 1794, ii. 252, § Jour, de Pharm. xxv. 340.
Jour, de Pharm. xxv. 340.
446 LIQUID PARTS OF ANIMALS.
CHAPTER X.
OF THE EGGS OF FOWLS.
THE eggs of all birds, so far as they have been examined, bear
a striking resemblance to each other. They consist of four parts,
1. The shell, which is white in the eggs of the common fowl, and
of many other birds ; but it is often coloured or spotted of va-
rious colours, so as to give it a beautiful appearance. 2. The
membrana putaminis, a thin translucent pellicle immediately
within the shell. At the great end of the egg this membrane is
detached from the shell, leaving a certain distance between them,
which is filled with air. 3. The white or albumen, a glairy liquid
consisting of albumen dissolved in water, and contained, like the
vitreous humour of the eye, in an extremely thin membrane di-
vided into cells. 4. The yolk, a thick and almost solid yellow
matter, inclosed in a peculiar membrane. This membrane, by
two ligaments called chalaza, is tied to the membrane of the al-
bumen, and thus the yolk is kept in the centre of the egg.
1. The shell of the common fowl was analyzed by Vauquelin*
and Merat Guilokf But both of these chemists seem to have
overrated the quantity of animal matter which it contains. Ac-
cording to Dr Prout's analyses, which seem to have been con-
ducted with scrupulous attention to accuracy, its constituents
are,
Carbonate of lime with a little carbonate ) Q-
of magnesia, . /
Phosphate of lime and magnesia, . 1
Animal matter, . . 2
100|
2. If we suppose the weight of the whole egg to be 1000
grains, the average weight of the membrana putaminis will be
2-35 grains. § This membrane has not been subjected to analy-
sis. According to Hatchett it consists of coagulated albumen.
* Ann. de Chim. Ixxxi. 304.
f Ann de Chim. xxxiv. 71. | Phil. Trans. 1822, p. 381.
§ Prout, Ibid.
EGGS OF FOWLS. 447
It is stated by Berzelius, I know not on what authority, to be
easily converted into gelatin when boiled in water.
3. The glairy liquid called the white coagulates into a firm
white solid when heated to 159°. Hence it is a solution of al-
bumen in water. This aqueous solution when evaporated to
dryness leaves about 14 per cent of albumen. Dr Bostock has
shown that it contains also a little mucus. According to him the
mean constitution of white of egg is,
Water, 80
Albumen, . 15*5
Mucus, . 4 '5
100*
Dr Prout determined by combustion the'quantity of fixed con-
stituents which albumen contains. If we suppose the original
weight of the egg to have been 1 000 grains, the following table
shows the weight of the fixed constituents in three different eggs :
No. 1. No. 2. No. 3.
Grains.
Sulphuric acid, . . 0-29 0-15 0-18
Phosphoric acid, . . . 0-45 0-46 0-48
Chlorine, . . . 0-94 0.93 0-87
Potash, soda, and carbonates of do. 2-92 2-93 2-72
Lime, magnesia, and carbonates of do. 0-30 0-25 0*32
4-90 4-72 4-57
It was long uncertain whether the sulphur and phosphorus
exist in the white of egg in the state of sulphuric and phos-
phoric acids, or in that of sulphur and phosphorus. What
renders the second of these suppositions probable is, that
the acids are too small in quantity to neutralize the bases ; and
it is well-known that the white of egg has an alkaline reaction.
The existence of these bodies in the state of sulphur and phos-
phorus has been at last proved by M. Mulder, as has been no-
ticed when treating of albumen in a preceding chapter of this
volume*
4. The yolk consists of water, albumen, and fixed oil, mixed
so as to constitute an emulsion. It contains also a colouring mat-
ter, for which it is indebted for its yellow colour. Dr Prout ana-
* Nicholson's Jour. xi. 246, and xiv. 142.
448 LIQUID PARTS OF ANIMALS.
lyzed it in the following manner : An egg was boiled hard in
distilled water, and the yolk in that state was found to weigh
316*5 grains. It was then partially dried by exposure to the
air for several weeks, and to remove the remainder of the water,
it was reduced to powder and dried in a heat somewhat more
than 212°. The total loss of weight was 170*2 grains, which
was considered as owing to the escape of water. The residue was
digested repeatedly in alcohol of 0*807 till that liquid came off
colourless. What remained was a white powder possessing many
of the properties of coagulated albumen, but differing from that
principle by the large quantity of phosphorus which it contained
in some unknown state of combination. The alcoholic solution
was of a deep-yellow colour, and deposited crystals of a sebace-
ous matter, and a portion of yellow semifluid oil. On distilling
off the alcohol the oil was obtained in a separate state. On
cooling, it became nearly solid, and weighed 91 grains. The al-
bumen weighed 55*3 grains. Hence the yolk consisted of,
Grains.
Water, v 170-2 or 53-78
Albumen, . 55-3 or 17*47
Yellow oil, . 91*0 or 28*75
316-5 100*00
But he found these proportions to vary a little in different eggs.*
According to Planche, 1000 parts of yolk of egg furnish at
an average 180 parts of oil. This oil consists of stearin and elain
in the following proportions :
Stearin, . 10
Elain, . 90
100
The stearin is white, solid, and does not stain paper like oil.
100 parts of boiling alcohol, of the specific gravity 0*805, dis-
solve 10*46 parts of this stearin. He found the stearin from the
fat of fowls of a fine white colour, and 100 parts of alcohol of
0*805 dissolved 10'09 parts of it, showing it to agree very near-
ly with the stearin from the yolk of egg.f
The elain from the yolk possesses the characters of a fixed oil,
but has not hitherto been subjected to a chemical investigation.
* Phil. Trans. 1822, p. 387. f Jour, de Pharmacie, ix. 2.
EGGS OF FOWLS. 449
Chevreul has found two colouring matters in the yolk, the one
red, and the other yellow.
Lecanu, besides the stearin and elain, extracted from the yolk
of egg a crystalline matter which melted at 293°, and which he
considered as of the same nature with cholesterin from the brain.*
Dr Proutf determined the quantity of fixed constituents of
dried yolk of egg by incineration. He pounded the yolk with
bicarbonate of potash in a mortar, and then heated it in a cover-
ed platinum crucible till flame ceased to escape from a small
hole in the lid. The contents when cold were removed from the
crucible and again pounded with nitre. The mixture was now
introduced by a little at a time till the whole was burnt. To the
residuum water was added, which dissolved every thing but the
earthy phosphates. From the aqueous solution everything was
obtained except the alkaline matter contained in the yolk. To
obtain these a new portion of the yolk was treated as before, sub-
stituting lime and nitrate of lime for bicarbonate of potash and
nitre. The following table exhibits the quantity of fixed matter
obtained in this way from three different yolks :
No. 1. No. 2. No. 3.
Sulphuric acid, . . 0-21 0-06 0-19
Phosphoric acid, . . . 3-56 3-50 4-00
Chlorine, . . . 0-39 0-28 0-44
Potash, soda, and carbonates of do. 0*50 0-27 0*51
Lime, magnesia, and carbonates of do. O68 0-61 0'67
5-34 4-72 5-81
Whether the sulphur and phosphorus exist in the yolk in the
state of acids, or as sulphur and phosphorus is not known, though
the last supposition is most probable. When we compare the
fixed constituents of the white and yolk, we cannot avoid being
struck with the difference. The white contains a much greater
quantity of fixed alkalies than of any other fixed constituent ;
while in the yolk the most abundant constituent is phosphoric
acid, which amounts to from 3*5 to 4 grains, or, if we suppose it
to exist, as phosphorus, it varies in a single yolk from 1*55 to
1*77 grains.
The specific gravity of a new laid egg varies from 1*080 to
* Berzelius, Traite de Chiraie, ix. 573. f Phil. Trans. 1822, p. 386.
Ff
450 LIQUID PARTS OF ANIMALS.
1-090. When kept, eggs rapidly lose weight and become spe-
cifically lighter than water. This is owing to the diminution of
bulk in the contents of the egg ; the consequence of which is that
a portion of the inside of the egg comes to be filled with air. Dr
Prout kept an egg two years, and found that it lost weight daily
at the average rate of 0-744 grains. The original weight was
907*5 grains, and after two years exposure to the atmosphere it
weighed only 363-2 grains. The total loss amounted to 544-3
grains, or considerably more than half the original weight. The
loss in summer was somewhat greater than in winter, owing, no
doubt, to the difference of temperature. Had the original weight
of the egg been 1000, then after two years exposure to the at-
mosphere it would be reduced to 400.
The relative weights of the shell and lining membrane, albu-
men, and yolk are very different. Supposing the original weight
of the egg to have been 1000, Dr Prout found the relative pro-
portions in ten different eggs as follows : —
Yolk.
Shell and membrane.
Albumen.
Grains.
104*8 ^
516*6
110*8 -0.
608-5
116*7 <;.
626*3
89-0 -o.
643-2
117-6
575*0
119-5 . 0.
575*3
98-0 --.
636-6
: 107-1 ;,.
596*0
118-3 ;0™
624*0
87*5
640*0
106-9 604*2 288-9 average.
When an egg is boiled in water it loses weight, particularly
if it be removed from the water when boiling, and be permitted
to cool in the open air. The water will be found to contain a
portion of the saline constituents of the egg. The loss of weight
from boiling is not constant, varying from twenty to thirty grains,
supposing the original weight of the egg to have been 1000 grains.
The quantity of saline matter obtained by evaporating the dis-
tilled water in which an egg was boiled, amounts at an average
to 0'32 grains. It is strongly alkaline, and yields traces of ani-
EGGS OF FOWLS. 451
mal matter, sulphuric acid, phosphoric acid, chlorine, and alkali,
lime and magnesia, and carbonates of lim i and magnesia ; in
fact, of all the fixed principles found to exist in the egg. But
the carbonate of lime is most abundant, and is obtained by eva-
poration in the form of a white powder.*
It is well known that when the egg is kept at a temperature
of about 100° by the warmth of the mother, or by any other ar-
tificial means for three weeks, a chicken is formed in it, which,
at the end of that period, breaks the shell. Dr Prout made a
number o ' t xperiments to determine the changes which take place
in the constituents of . the egg during the period of incubation, f
The following is a summary of these experiments :
If we suppose the original weight of the egg to be 1000 grains^
it will be found that, after a week's incubation, the average loss
is about fifty grains. The following table shows the amount of
the various constituents of the egg on the eighth day of incu-
bation in two different eggs : —
No. 1. No. 2.
Grains. Grains.
Unchanged albumen, . 232-8 . 247'1
Modified albumen, . ,
Liquor amnii, membranes, ~i 97 A 9
blood-vessels, &c. f
Animal, . . . 22'0 I
Yolk, .... 301-3 . 324-5
Shell and loss, . 167-1 . 153-2
1000-0 1000-0
As soon as the process of incubation has commenced the yolk
becomes more fluid than usual ; the liquor amnii increases, and
that portion of the albumen occupying the upper and larger end
of the egg begins to assume a peculiar aspect. When the
egg is boiled it puts on an appearance somewhat resembling
that of curds-and-whey. It has a yellow colour, and contains a
portion of the oil of the yolk. Hence it would appear that a por-
tion of the oil of the yolk must in some unknown way pass into
that part' of the albumen. It is this portion of the albumen
which, in the preceding table, is distinguished by the name of
modified albumen. The yolk at this period has become more
* Prout, Phil. Trans. 1822, p. 380. f Ibid. p. 388.
LIQUID PARTS OF ANIMALS.
fluid, and appears larger and of a paler colour than natural, and
from the preceding table would appear to have somewhat increas-
ed in weight. This would indicate a portion of the albumen ad-
ded to it, and more than compensating the loss of oil.
The following tables exhibit the quantity of fixed constituents
in these contents of the egg on the eighth day of incubation : —
No. 1.
Sulphuric
Phos.
Chlorine.
Potash,
Lime,
acid.
acid.
&c.
&c.
Grains.
Grains.
Grains.
Grains.
Grains.
Unchanged albumen,
0-13
0-27
0-19
1 03
0-18
Modified albumen, }
liquor amnii, &c. £
0-08
0-38
0-45
1-17
0-12
Yolk,
0-09
4-03
060
0-80
0-68
0-30 4-68 1-24 3'00 0-98
No. 2.
Unchanged albumen,
0-18
0-18
0-24
1-50
0-12
Modified albumen, )
liquor amnii, &c. J
0-10
0-25
0-30
0-70
0-12
Yolk,
0-08
4-00
0-56
0-75
0-67
036 4-43 1-10 2-95 0-91
From these tables it appears that, though the oily matter of
the yolk has made its way to the albumen, very little of the phos-
phorus has been removed from it.
The following table shows the fixed constituents at the end of
the tenth day of incubation : —
Sulphuric Phos. Chlorine Potash, Lime,
acid. acid. soda, &c. mag. &c.
Grains. Grains. Grains. Grains. Grains.
Unchanged albumen, 0-27 0-14 0-24 1-13 0-12
Modified albumen, &c. 0-08 0-65 0-68 1-36 0-27
Yolk, . . 0-05 335 030 0-62 0-66
0-40 4-14 1-22 3-11 1-05
At this period the quantity of phosphorus in the yolk is some-
what diminished and increased in the animal and its appendages.
The chlorine and alkalies seem also to have diminished in the
yolk.
At the end of the second week of incubation the egg has lost
upon an average 130 grains, supposing its original weight to
have been 1000 grains. The weight of its constituents in two
different eggs are as follows : —
EGGS OF FOWLS.
453
Unchanged albumen,
Liquor amnii, &c.
Animal,
Yolk,
Shell and loss,
No. l.
Grains.
175-5
273-5
70-0
250-7
230-3
1000-0 1000-0
At this period the animal has acquired a considerable size,
while the albumen has diminished in a corresponding degree.
The albumen has acquired a very firm consistence when coagu-
lated by heat. The liquor amnii is more fluid, and the modified
albumen has disappeared. The yolk has resumed its original
size and consistence.
The following table shows the fixed constituents at this period
in two different eggs : —
Phos. Chlorine,
acid.
Grains.
0-22
Sulphuric
acid.
No. 1. Grains.
U unchanged albumen, 0-07
Liquor amnii, mem-
branes, &c. . 0-06
Animal, . 0-06
Yolk, . 0-30
Grains.
0-09
Potash, Lime, mag-
soda, &c. nesia, &c.
Grains. Grains.
0-73 0-10
0-21
0-23
3-34
0-71
0-09
0-16
0-96 0 08
0-46 0-27
0-68 0 69
No. 2.
Unchanged albumen,
Liquor amnii, mem-
brane, &c.
Animal, .._»_-,.
Yolk,
0-49
0-11
0-03
0-06
0'20
4-00
0-19
0-20
0-20
3-30
1-05
023
0-70
0-07
0-10
2-83
0-97
1-14
009
1-07 0-08
0-44 0-28
0-42 0-70
0-40 3-93 MO 2-90 1-15
An egg analyzed two days later, or on the seventeenth day of
incubation, gave the following results : —
Sulphuric Phos. Chlorine. Potash, Lime, mag-
acid* acid. soda, &c. nesia, &c.
Grains. Grains. Grain. Grains. Grains.
Liquor amnii, mem-
branes, animal, &c. 0-34 1-70 0-68 2-40 1-10
Yolk, • [0-10 2-50 0-30 0-56 0-75
0-44 4-20 098 2-96 085
At this period ossification has made considerable progress
454 LIQUID PARTS OF ANIMALS.
The yolk has parted with some of its phosphorus, which appears
in other principles of the egg.
The following table shows the contents of the egg at the end
of the third week, or at the full term of incuhation in two differ-
ent eggs:—
No 1.
Grains.
Residuum of albumen, membranes, &c. 29-5
Animal, . 15 . 555-1 .
Yolk, Ifrfi .'si^j 167-7 xj.&
Shell and loss, 247 -7
1000-0 1000-0
At this period all the important changes of incubation are com-
pleted. The albumen has disappeared or is reduced to a few
dry membranes together with earthy matter. The yolk is con-
siderably reduced in size, and is taken into the abdomen of the
chick, while the animal has attained a weight nearly equal to the
original weight of the albumen, together with that lost by the
yolk, minus the total loss of weight sustained by the egg during
incubation. The alkaline matters and chlorine have diminished
in quantity, while the earthy matters have considerably increased.
The following table shows the fixed constituents in the contents
of two eggs at the end of the period of incubation :—
Sulphuric Phos. Chlorine. Potash, Lime, &c.
acid. acid. &c.
Grains. Grains. Grains. Grains. Grains.
Residue of albumen, &c. 004 0-12 0-09 0-23 0 J2
Animal, . 0-44 3-02 0-55 2-26 2-58
Yolk, .><•?. 0-04 1-06 0-03 0-06 1'26
0-52 4-20 0-67 2-55 3-96
Residue of albumen, &c. 0-03 0-13 0-09 0-25 0-12
Animal, . 0-21 2-71 0-68 2-12 2-60
Yolk, VJV« o-02 1-23 0-06 0-03 MO
0-26 4-07 0-83 2-40 3-82
It follows, from these experiments, that during the last week
of incubation the yolk loses most of its phosphorus, which is
found in the animal converted into phosphoric acid, and com-
bined with lime, constituting its bony skeleton. This lime does
not exist in the recent egg, but is derived from some unknown
source during the process of incubation.
ROE OF FISHES. 455
Mr Hatchett made the curious remark that in the ova of those
tribes of animals, the embryos of which have bones, there is a por-
tion of oily matter, and in those ova whose embryos consist en-
tirely of soft parts, there is none. In what way the oily matter
contributes to the formation of bone, it is impossible, in the pre-
sent state of our knowledge, even to conjecture. Nor can any
source of the lime of the bones be pointed out except the shell.
And it would be very difficult to determine whether the shell
loses lime during the process of incubation.
CHAPTER XL
OF THE ROE OF FISHES.
THE roe of fishes is well-known as the ovarium of that tribe
of animals. It consists of a congeries of very small eggs ; the
number of these in a single fish is remarkable. M. Petit found
342,244 in a carp of eighteen inches, and Leeuwenhoek states
the number in a cod-fish to be 9,344,000. Now, as each of
these is capable of producing a fish, we need not be surprised at
the immense numbers which swarm in the ocean and rivers,
notwithstanding the numerous enemies to which they are ex-
posed.
The first set of experiments to determine the chemical nature
of the roe of fishes was made by Vauquelin on that of the pike
(Esox lucius) in 1817.* In 1823, M. Morin examined the roe of
the common trout ( Salmofario), and the carp ( Cyprinus carpio,
Linn.f) ; and in 1827, M. Dulong d'Astafort published a chemi-
cal examination of the roe of the barbel ( Cyprinus barbus, Linn.)J
1. Vauquelin analyzed the roe of the fish in the following man-
ner : Four pounds of it were washed with water, till everything
soluble was taken up. The liquor being evaporated by the ap-
lication of heat coagulated into a white flocky matter, which,
when dried, was gray and brittle, soluble in caustic potash, and
precipitated by infusion of nut-galls and by nitric acid in white
flocks. It was albumen.
When a portion of the coagulum from aqueous solution was
incinerated, it left a white alkaline ash, which consisted of car-
* Jour, de Pharmacie, iii. 385. f Ibid, ix, 203, \ Ibid. xiii. 521.
456 LIQUID PARTS OF ANIMALS.
bonate of potash, phosphate of potash, common salt, and phos-
phate of lime.
The liquid, from which the coagulated albumen had precipi-
tated, having been evaporated to dryness, left a yellowish-brown
extract, which was alkaline, had a fish smell, and tasted strong-
ly saline. It was insoluble in alcohol, but dissolved in water.
Alcohol threw down from the aqueous solution brown flocks,
which redissolved in water, and possessed the characters of gela-
tin. When burnt, it left an ash consisting chiefly of phosphate
of magnesia, a little phosphate of lime, and carbonate of lime.
The alcohol, which precipitated the above substances, when
evaporated, left a brown matter, having a saline and pungent
taste, in which cubic crystals of chloride of potassium were form-
ed. When triturated with potash, this substance gave out a
strong smell of ammonia.
The roe of the pike formerly treated with water was now
boiled in strong alcohol, and the boiling solution was passed
through the filter. It was yellow, and became muddy when
mixed with water or allowed to cool. When the alcohol was evapo-
rated it left an oily matter, having an orange-colour, and the taste
and smell offish. It contained a notable quantity of phosphorus.
The roe thus exhausted by water and alcohol was burnt in a
crucible. It left a charcoal difficult to incinerate, and which un-
derwent a sort of imperfect fusion by the action of the fire.
When digested in water it furnished an acid liquor precipitating
lime and barytes water in white flocks, and oxalate of ammonia
in powder. It therefore contained phosphoric acid and lime.
From this imperfect analysis it appears that the roe of the pike
contains,
1. Much albumen.
2. An oil.
3. An animal matter, resembling gelatin.
4. Chlorides of potassium and sodium.
5. Sal-ammoniac.
6. Phosphates of potash, lime, and magnesia.
7. Sulphate of potash.
8. Phosphorus.
The analogy between the constituents of this roe and those of
the eggs of common fowls is very remarkable.
2. M. Morin followed much the same plan as Vauquelin in
analyzing the roe of the common trout
ROE OF FISHES. 457
He digested sixty-four grammes of the roe in successive por-
tions of water as long as the liquor dissolved anything, The
water being heated deposited flocks, which, being collected on a
filter and dried, was gray, and dissolved completely in caustic po-
tash. From this solution it was precipitated in white flocks by
tincture of nut-galls. When distilled per se, it furnished an oily
and very alkaline liquor,, having a fetid odour. The residual
charcoal being incinerated, left a small quantity of white ash,
which had an alkaline reaction. It consisted of carbonate of potash,
phosphate of potash, and phosphate of lime. The flocks were ob-
viously coagulated albumen, mixed with the above-named salts.
The liquid from which the albumen had separated being eva-
porated to dryness, left a yellowish-brown extract, having a dis-
tinct flavour of beef-tea. When treated with strong alcohol, it
only partially dissolved. The alcoholic solution, being mixed
with water, was abundantly precipitated by tincture of nut-galls,
acetate of lead, and nitrate of mercury. When evaporated, it
left a yellowish residue soluble in water and in alcohol. From
these characters, Morin considered the substance to contain os-
mazome. When triturated with potash, it gave out a strong
smell of ammonia, which he conceived to exist in the state of sal-
ammoniac. When burnt it left a white ash soluble in water, and
containing carbonate of soda and chloride of potassium.
The portion of the extract left by the alcohol was totally so-
luble in water. The solution was precipitated in yellow flocks
by tincture of nut-galls. The mineral acids occasioned no change
in it. Morin considered it as gelatin. When heated it swelled
up, gave out an animal odour, and left a white alkaline ash con-
sisting of carbonate of soda and phosphate of lime.
The roe, which had been treated with water, was digested in
hot alcohol. The filtered alcoholic solution was yellowish and
muddy. When evaporated it left a yellow oil, having a fish
smell and soluble in ether. It was identical with the oil extract-
ed by Vauquelin from the roe of the pike. When burnt it left
a minute quantity of phosphoric acid.
The 'residue of roe treated with water and alcohol, had the ap-
pearance of indurated albumen. It dissolved in caustic potash
without giving out any ammonia. Muriatic acid dropt into the
solution threw down white flocks soluble in an excess of acid.
Heated in a platinum crucible, it left a charcoal difficult to inci-
458 LIQUID PARTS OF ANIMALS.
nerate. It was similar in its nature to the charcoal left after
heating the exhausted roe of the pike.
From his analysis Morin concludes that the roe of the com-
mon trout contains,
1. Albumen. 7. Phosphorus.
2. Osmazome. 8. Carbonate of soda.
3. Gelatin. 9. Carbonate and phosphate
4. Oil. of potash.
5. A solid matter resembling 10. Chloride of potassium,
coagulated albumen. 11. Phosphate and carbonate
6. Sal-ammoniac. of lime.
3. The roe of the carp was analyzed by Morin in the same
manner. He obtained,
1. Much albumen. 6. Chloride of potassium.
2. Osmazome. 7. Carbonate of soda.
3. Gelatin. 8. Phosphate of lime and car-
4. Oil containing phosphorus. bonate of lime.
5. Coagulated albumen.
4. M. Dulong d' Astafort analyzed the roe of the barbel in the
same way as the preceding analyses had been conducted. It has
been long known that the roe of the pike has a purgative quali-
ty. And M. Dulong d' Astafort informs us that those of the bar-
bel have the same property. This effect is ascribed to the oily
matter which both contain, which, instead of being a tasteless
fixed oil like that in the yolk of the common fowl, possesses very
acrid properties. The roe of the barbel was found to contain
the following substances :
1. Albumen. 7. Sal-ammoniac.
2. An acrid oil. 8. Phosphates of lime and po-
3. Osmazome. tash.
4. Gelatin. 9. An organic salt, with base
5. Phosphorus. of potash.
6. Chlorides of potassium and
sodium.
These analyses show a striking analogy between the roes of
fishes and the eggs of fowls.
URINE. 459
CHAPTER XII.
OF URINE.
No animal "substance has attracted more attention than urine,
both on account of its connection with various diseases, and of
the remarkable products that have been obtained from it. Mr
Boyle made several attempts to determine the nature of the salts
which it contained ;* though, from the imperfect state of che-
mistry in his time, it was not possible that he could have succeed-
ed. The discovery of phosphorus from urine by Brandt, in 1669,
naturally drew the attention of chemists to that liquid. Boyle
discovered the process of Brandt, and taught his operator, God-
frey Hankwitz, the method of extracting it from that liquid ; and
it is well known, that for many years Hankwitz was the person
who supplied all the chemists in Europe with this curious sub-
stance.
The putrefaction of urine and the great quantity of ammonia
which it yields when distilled, must have been observed at a very
early period, and accordingly we find the facts connected with
these processes described by the earliest chemists who turned
their attention to urine*. Lemeri, for example, whose system of
chemistry was published in the latter part of the seventeenth cen-
tury, has a whole chapter on the subject. Margraaf improved
the process of extracting phosphorus from urine in the year 1743,
and in 1746 he extracted ammonia-phosphate of soda or micro-
cosmic salt from urine, and described its properties.!
But the first person who threw any great light upon the con-
stituents of urine was Rouelle Junior. In his researches on
urine, published in the Journal de Medecine for 1773 and 1777,
he describes the properties of urea, which he extracted from urine
by means of alcohol, and obtained in the state of crystals. To
this substance he gave the name of soapy matter. Rouelle point-
ed out, likewise, some of the salts of urine, though not so suc-
cessfully. In 1776, Scheele discovered uric acid in urine, and
showed that it constituted one of the most common of the sub-
* Shaw's Boyle, iii. 316, 376, 377.
t Opuscules Chimiques de Margraaf, i. 30, 123.
460 LIQUID PARTS OF ANIMALS.
stances by the concretion of which calculi are produced. He
detected also phosphate of lime in urine.*
In 1808, Berzelius published the second volume of his Ani-
mal Chemistry, in which he gives a long account of the proper-
ties of urine, and mentions the action of reagents on it, but gives
no quantitive analysis. His well-known analysis of urine appear-
ed first in his paper entitled General Views of the Composition of
Animal Fluids, published in 1813 in the third volume of the Me-
dico-Chirurgical Transactions.!
About ten years after this, I made many experiments on urine,
and likewise analyzed this liquid from a healthy individual ; but
the paper lay by me unpublished till it was inserted in the second
volume of the Records of General Science in 1 835. In 1839, an
elaborate paper on the variation of the constituents of urine in
the same and in different individuals was given to the public by
M. Lecanu.J Of this important paper an abstract will be given
in this chapter.
Urine is secreted by the kidneys and conveyed by the ureters
to the bladder, from which it is voided occasionally when its pre-
sence gives rise to a feeling of uneasiness. It was generally sup-
posed by physiologists that the solid substances which it holds in
solution were formed by the action of the kidneys ; but the expe-
riments of Prevost and Dumas have made it almost certain that
they all exist in the blood, and that the office which the kidney
performs is only to separate them from the other constituents
with which they are mixed in the blood-vessels. For when they
extirpated the kidneys from animals and examined their blood
two or three days afterwards, they were able to detect in it
a sensible quantity of urea.
Human urine when newly emitted has a yellow colour, more
or less deep, according to circumstances. It is transparent, though
sometimes when left at rest in a glass it deposits a few flocks of
mucus. It has a distinct aromatic smell, which has been compar-
ed to that of violets. When it cools, the aromatic smell leaves
it, and is succeeded by another well-known by the name of uri-
nous. This odour is in two or three days (when the urine is from
young or middle-aged persons) succeeded by another which has
* Scheele's Essays, p. 199. f Annals of Philosophy, ii. 422.
t Jour, de Pharmacie, xxv. 681, 746.
URINE. 461
considerable resemblance to that of sour milk. This smell gra-
dually passes off in its turn, and is succeeded by a fetid ammo-
niacal odour. This odour appears much sooner in the urine of
old individuals than in that of young persons. It has a disagree-
able, bitter, saline taste, of very various degrees of intensity,
sometimes so slight that it can barely be perceived. In such cases,
the urine is nearly colourless ; when high-coloured, the taste is
always strong.
Nothing is more various than the colour of urine. Most com-
monly it is yellow, of various shades. Sometimes it passes into
orange, or even into red. It is said to be deeper in men than in
women, but I have not been able to satisfy myself that such a
difference exists. There is an intimate connection between the
depth of the shade and the quantity emitted. When the urine is
scanty it is always high-coloured ; hence one reason of the red
colour of urine in fevers. When the quantity emitted is great
the colour is. pale. I have seen it in cases of hysteria so nearly
colourless that the presence of the usual constituents ef urine
could only be discovered by concentrating it. By this treatment
it gradually acquires the yellow colour of common urine, and
may be even made red by carrying the concentration farther. Some-
times urine contains bile, which gives it an orange tint. Muriatic
acid changes the colour of urine containing bile to green. Oc-
casionally the colour of urine is so deep that it appears black.
This change is sometimes owing to a mixture of blood ; but some-
times to substances taken into the stomach. Thus, when prepa-
rations of iron are given at the same time with rhubarb the urine
is said to assume a blackish colour. Urine has frequently a red
colour, and the shade varies from rose-red to scarlet. Red urine
usually characterizes an inflammatory state of the system. Such
urine is always scanty. Other colours are mentioned by medical
men. Thus urine has been described as grayish, greenish, and
&w/f-coloured. Dr Prout mentions a case in which it threw up a
cream-like milk. Such urine might be called white, and proba-
bly owed its peculiar qualities to the presence of chyle.
Lecanu* examined 93 different specimens of urine, and has
given us the following table of their colours :
28 had a light-yellow colour.
* Jour, de Pharmacie, xxv. 694.
462 LIQUID PARTS OF ANIMALS.
24 had a deep -yellow colour.
27 had a red colour.
7 had a greenish colour.
7 had a brown colour.*
The smell of urine is varied by causes apparently trifling.
Asparagus gives it a peculiar fetid odour, while oil of turpen-
tine taken into the stomach soon communicates to urine the smell
of violets. In many individuals almost every article of food pro-
duces a corresponding change on the odour of urine. In the
disease called diabetes the urine has a peculiar odour, not easily
described. Perhaps the term sweetish might be applied to it.
The specific gravity of urine varies very much according to
circumstances. The following table exhibits the extremes as
stated by various chemists and physiologists :
Cruikshanks. Chossat. Lecanu. Thomson.
Maximum, 1-033 . 1-0388 . 1-038 . 1*048
Minimum, 1-005 . 1-0016 . . 1-010 . 1-000148
Both, of the urines whose specific gravity were determined by
me, were the urines of disease. The first in a case of diabetes,
and the second in a case of hysteria.
The following table exhibits the mean specific gravity of the
urine of eight individuals experimented on by Chossat. f The
second column gives the mean quantity of solid matter in the
urine of each individual passed in twenty-four hours :
Sp. gravity. Solid contents
in Grains.
1-0127 ijj*« fctfcfl 307-5
1-0156 » . .-, . 389.
1-0178 ;,./ ,-;.< 390-6
1-0213 ? . 500'4
1-0222 Jvfo . 513-1
1-0232 .1 . 534-3
1-0240 >, •:•-- . 510-9
1-0264 568-2
Mean, 1-0204 464-25
According to this table of Chossat the mean specific gravity of
urine in a state of health is 1-0204. I have found the mean spe-
* Jour, de Pharm. xxvi. 202. f Jour, de Physiol. v. 197.
URINE. 463
cific gravity of the urine of a middle aged man in perfect health
to be 1O1385. It varied in the course of a fortnight from 1-0093
to 1*0192. But it was observed occasionally as high as 1-0266.
Lecanu found the mean specific gravity of the urine of young men
greater than that of old persons.* According to Becquerel the
mean specific gravity of urine is as follows :
In males, . . 1*0180
In females, w'j f- 1-01512
Mean, k&o6 1-01656
I found in a healthy middle aged individual the mean quan-
tity of urine voided in twenty-four hours, amount to 3^ Ibs avoir-
dupois. But it varied a great deal, being sometimes as low as
2-133 Ibs., and sometimes as high as 4*857 Ibs.
Lecanu has given us a considerable series of facts on the quan-
tity of urine voided by different individuals in twenty- four hours:
In thirteen individuals it varied from 1*16 Ibs. to 5-007 Ibs.
In five young men from the age of 20 to that of 40 years, the
quantity of urine voided in 24 hours, varied from 1 -64 Ibs. to
5-007 Ibs.
In young men the quantity of urine voided is greater than in
old men or in infants.
When we take the mean of a number of days, the quantity of
urine voided in 24 hours by different individuals approaches
much nearer to equality.
The mean of 48 experiments gives 2-795 Ibs. avoirdupois for
the quantity of urine voided in 24 hours.
Haller states it at 3*457 Ibs.
Proutat, . 2*300
Bostock, ;; . 2-822
Bayer, ">j 2-771
Lecanu, *'. 2*795
Thomson, . 3*333
Mean, . 2*913, or very nearly 3 Ibs.
avoirdupois.
According to Becquerel,f the mean quantity of urine in 24
hours, is,
* Jour, de Pharmacie, xxv. 695. f Semeiotique des Urine, p. 6.
464
LIQUID PARTS OF ANIMALS.
In males, 2 '7 94 Ibs. avoirdupois.
In females 3-024 Ibs.
Mean, . 2-909 Ibs.
This agrees nearly with the result of Lecanu.
The quantity of urine depends partly upon the quantity and
nature of the food. The average quantity is greater when the
food is generous and abundant than when it is meagre and scan-
ty. Chossat found, however, that the quantity of urine voided
was greater when the food was bread than when it was restrict-
ed to flesh meat. He found also that the secretion of urine is
dimished in the evening. But to this there must be many ex-
ceptions ; for I did not find it so in the cases that came under
my observation.
A good deal of loose statements have been made respecting
the quantity of urine voided at different times of the day, and
respecting the specific gravity of the urine when so voided ; per-
haps the following table may not be altogether useless. The ex-
periments were made on the urine of a healthy individual be-
tween 50 and 60 years of age, and complete reliance may be
placed upon the results, as every precaution was taken to insure
accuracy :
September 23d.
September 24th.
r
r
When
Cub. in.
Sp. gravity
When
Cub. in.
Sp. gravity.
voided.
at 95°.
at 60°.
voided.
at 95°.
at 60°.
11 A.M.
4-
1-0192
11 A.M.
5-75
1-0173
1 P. M.
7-75
1-0165
12f P. M.
6-75
1-01605
24
4-8
1-0126
H
9-75
1-0069
3|
3-5
1-0176
2*
8-
1-00808
44
4-8
1-0186
4?
5-75
1-0136
9f
7-5
1-0206
5f
5-5
1-0146
11*
4-0
1-0226
9i
8-2
1-0186
1 A.M.
14-0
—
12
10-
1-0146
4
24-0
1-0126
4 A. M.
23-
1-0115
7*
9-75
1-0106
8
10-25
1-0136
8*
6-25
1-0126
8§
3-75
1-0156
9
4-50
1-0156
—
—
—
Total,
94-85 or
3-403 Ibs.
Mean,
Total,
1-01249
96-7 or
3-47 Ibs.
Mean,
1-01301
URINE.
465
September 25th.
September 26th.
When
Cub. in.
Spr. gr.
When
Cub. in.
Spr. gr.
voided.
at 95°.
at 60°.
voided.
at 95°.
at 60°.
llf A. M.
6-
1-0187
11 A. M.
8-8
1 0126
1 P. M.
7-5
1-0113
Noon,
7-5
1 0086
. ) 1
4-8
1-0101
11 p. M.
8-
1 0114
3±
5-5
1-00958
2|
7-
1-0101
5f
6-5
1-0126
5
5-
1-0156
10
8-8
1-0166
Ql
8-5
1-0055
U4
8-5
1-01059
9i
7-8
1-0126
5 A. M.
25-5
1-01059
10—
8-25
1-0065
8
8-
1-01059
11
6-25
1-0065
8f
5-5
1-0115
111
3-66
1-0065
...
...
...
3 A. M.
23
1-0065
.. .
...
...
6
18-8
1-0086
...
...
...
8-
13-5
1-0065
...
...
...
sf
8-
1-0086
Total,
86-6 or
Total,
134-06 or
3-1 Ibs.
4-875 Ibs.
Mean,
1-01156
Mean,
1 -0093
September 27th.
October 1st.
lOg^ A. M.
4-
1-0246
11 A.M.
4-5
1-0204
Noon,
8-8
1-0117
11 p^ jyjr^
6-5
1-0175
12^ P. M.
8-2
1 -0047
8f
6-75
1-0111
(I
7-8
1-0082
s|
4-8
1-0156
2£
6-
1-0082
10
9-
1-0146
4
5-8
1-0106
Hi
16-
1-0096
6
6-25
1 0115
5| A. M.
25-
10075
7f
2-25
1-0166
8
9-
1-0101
] 1^
7-8
1-0216
8i
5-75
1-0101
5| A. M.
20-
1-0106
...
...
8
11-
1-0106
>%
...
9
6-5
1-0106
...
...
...
Total,
94-4 or
Total,
87-3 or
3-424 Ibs.
3-17 Ibs.
Mean,
1-01199
Mean,
1-0111
October 2d.
A
October 3d.
llf A. M.
6-25
1-0197
1 IT A. M.
6-
1-0192
l| P. M,
4-
1-0197
l| P. M.
8-75
1-0152
41
4-
1-0188
3f
6-5
10136
6
4-
1-0201
41
3-25
1-0206
10*
5-25
1 0226
6
1-8
1-0206
11 ,
525
1-0216
10
6-
1-0246
5§ A. M.
25-
1-0086
HI
4-
1-0266
8
11-5
1-0086
6} A. M.
12-5
1-0246
8?
7-
1-0106
8
9-25
1-0176
8|
10-5
1-0146
Total, .
72-75 or
Total, .
68-55 or
2-626 Ibs.
2£ Ibs.
Mean, ,
1 0134
Mean,
1-0192
466
LIQUID PARTS OF ANINALS.
October 4th.
October 5th.
When
voided.
Cub. in.
at 95°.
Sp, gr.
at 60°.
When
voided.
Cub. in.
at 95°.
Sp. gr.
at 60°.
11| A. M.
8-5
1-01809
Noon
7.75
1-0186
12| P. M.
8-
1-0134
1 P.M.
8.5
1-0098
1
14-75
1-0077
1|
7-
1 -0098
3£
9-5
1-00958
4
7-2
1-0115
5
4-8
1.0131
6J
5-
1-0146
9£
8-5
1-0176
10
5-
1-0216
12
6 A. M.
8
8-5
24-
IB-
1-0166
1-00958
1-00958
llf
7| A. M.
2-
12-
4-
1-0256
1 -0256
1-0236
8A
S'
1-0106
Total,
102-55 or Total, . 58-48 or
4-386 Ibs. 2-133 Ibs.
Mean, . 1-0192 Mean, . 1-0173
From the inspection of the preceding tables it will be at once
apparent how very various the urine is both in its quantity and
specific gravity, even when the individual voiding it enjoys per-
fect health.
The mean specific gravity of the urine passed during these
ten days is 1-013859. The lowest specific gravity is 1«0047,
and the highest, 1-0266.
The mean quantity passed per day was 90*91 cubic inches, or
3-307 Ibs. avoirdupois. The least passed on any day was 58*15
cubic inches, or 2-133 Ibs. ; the greatest quantity was 133*37 cu-
bic inches, or 4*857 Ibs.
The preceding tables do not tally well with the universally
received opinion that the heaviest urine is that which is passed on
getting up in the morning. This was not the case in any one of
the ten days contained in the tables. On the contrary, the light-
est urine passed on the 23d of September, the 1st October, and
the 2d of October was that of the morning, and on all the other
days, save one, the lightest urine was that passed between twelve
and four p. M. from four to eight hours after breakfast, but be-
fore dinner.* On the contrary, the heaviest urine was in one
case passed one hour after dinner, and generally from three and
a-half to five and a-half hours after a meal.
I made a comparison between the liquid taken into the sto-
* Breakfast was between eight and nine A. M. j dinner at four p. M., and tea
at six p. M. There was no supper.
4
URINE. 467
mach and the urine passed for five consecutive days. Some
days the urine exceeded the drink ; but upon the whole, the
drink was to the urine nearly as eleven to ten. On one day the
drink was to the urine as 100 I 68-2, on another as 73£ I 102-02.
If the induction were sufficient, it would follow that the drink
exceeds the urine by one-tenth part. Hence if the mean quan-
tity of urine voided by 2-913 Ibs., that of the drink will be 3-204
Ibs. Chossat states that in his very numerous trials, the average
quantity of drink was to that of the urine as ten to nine nearly.
Varying somewhat according to the temperature, the quantity of
urine being greatest in the coldest weather.
The number of times that urine is voided in twenty-four hours
varies greatly in different individuals. I know an individual who
enjoys good health, and who passes urine at an average only three
or four times a-day. The greatest number of times in the pre-
ceding tables is fourteen times and the smallest nine times.
When urine is voided from a person in perfect health, it al-
ways contains an uncombined acid ; for it reddens litmus-paper,
and the change is permanent, and therefore not owing to carbo-
nic acid. Various opinions have been stated respecting the na-
ture of this acid. Proust and Fourcroy and Vauquelin suppos-
ed it to be the phosphoric. Urine contains a small quantity of
phosphate of lime, which may be precipitated from it by by caus-
tic ammonia. Now, as phosphate of lime is insoluble in water,
while a little of it is actually held in solution in urine, it was not
unreasonable to conjecture that it was in the state of biphosphate
of lime, which is slightly soluble in water, and capable of red-
dening litmus -paper. But a very simple experiment is sufficient
to show that urine contains no biphosphate of lime. Evaporate
urine to dryness, and ignite the residue. The residual salts do
not act on litmus-paper. Hence the free acid must be volatile,
since it is dissipated by a red heat.
Berzelius affirms that urine contains lactate of ammonia and
free lactic acid. I have not been able to verify this statement
by experiment ; the quantity obtained being always too small
to enable me to investigate its nature. I mixed sulphuric acid
with fresh urine till it tasted distinctly acid, and distilled over a
third of the mixture from a glass retort, by means of a gentle
heat. The liquid thus obtained was tasteless, and had no per-
468 SOLID PARTS OF ANIMALS.
ceptible smell. .It slightly reddened litmus-paper. It was
mixed with carbonate of soda, till it became slightly alkaline.
Being now evaporated to dryness, and a drop of sulphuric acid
let fall upon the small saline residue, a smell was emitted strong-
ly urinous, but mixed with a sensible odour of vinegar. Hence
it was obvious that acetic acid existed in the residue. But it
might have been formed from lactic acid during the process. For
Scheele showed long ago that lactic acid is very easily converted
into acetic acid.
Urine contains always some uric acid, as was first observed by
Scheele. It separates in minute crystals when the urine is
mixed with nitric acid, and set aside for some time in an open
glass vessel. Berzelius states the average quantity of uric acid
in urine at j oloothof its weight.' Lecanu states the uric acid in
100 urine to be 0-75. A copious table of the quantity of uric
acid in many different specimens of urine, as determined by Le-
canu, will be given in a subsequent part of the present chapter.
I found that 1000 parts of urine of the specific gravity 10*185
let fall 0*242 of uric acid when mixed with nitric acid. Now,
according to the experiments of Prout, uric acid does not dis-
solve in 10,000 times its weight of water, while urate of ammonia
is soluble in about 500 times its weight of that fluid. Hence it
is natural to infer that uric acid in urine is in the state of urate
of ammonia. And, as urate of ammonia reddens vegetable blues,
the acidity of the urine may be partly owing to the presence of
urate of ammonia.
The most remarkable substance in urine is urea. According
to Berzelius, it exists in urine to the amount of 3 per cent. But
he does not give us the specific gravity of the urine tried. Le-
canu found that urine of sp. gr. 1-030 contained 2*94 per cent.
I obtained from urine of specific gravity 1-0185 2*364 per cent,
of urea. A copious table of the quantity contained in different
urines will be given at the end of this chapter.
Besides these substances, and the colouring matter, which has
not hitherto been obtained in a separate state, urine contains always
phosphoric and sulphuric acids, together with lime, magnesia, po-
tash, and ammonia, and a notable quantity of common salt.
The first analysis of urine was published by Berzelius in 1813.
He does not give the specific gravity of the urine examined by
him. But he states that it became turbid on standing. Hence
URINE.
469
it could not have been the urine of a healthy individual. The
result of his analysis was as follows :
Water, .... 933-00
Urea,* • . . .30-10
Sulphate of potash, . . . 3 '71
Sulphate of soda, . . . 3' 16
Phosphate of soda, . . . 2'94
Common salt, .0 ".,si . . 4-45
Phosphate of ammonia, . . 1*65
Sal-ammoniac, i{»$ ^ . . 1*50
Free lactic acid, . .u
Lactate of ammonia,
Animal matter soluble in alcohol, and accompanying
the lactates, . . .
Animal matter insoluble in alcohol,
Urea not separated,
Earthy phosphates, with trace of fluate of lime, '. 1OO
Uric acid, . . . .1-00
Mucus of the bladder, . . . 0*32
Silica, .... 0-03
1000' f
I made an analysis of healthy urine of specific gravity 1*0185
about the year 1824, and obtained from 1000 grains of it the
following substances :
Phosphate of lime, . 0-209
Phosphoric acid, . 1*131
Sulphuric acid, . 0-481
Chlorine, .;.-,n . 5-782
Uric acid, .-^i, . 0-242
Soda, >.«ji . 4-610
* MM. Cap and Henry have shown by experiments which appear conclusive,
that the urea in urine is in the state of lactate, being combined with lactic acid.
See Jour, de Pharm. xxv. 133.
Lactate of urea is composed of,
1 atom lactic acid, 8-875
1 atom urea, . 7 "5
16-375
t Annals of Philosophy, ii. 423.
470 LIQUID PARTS OF ANIMALS.
Potash, . . 2-051
Ammonia, . . 0*130
Urea, . . 23-640
38-276
and I considered that these substances were combined so as to
form the following bodies :
Urate of ammonia, . 0-298
Sal-ammonia, . 0*459
Sulphate of potash, . 2-112
Chloride of potassium, 3-674
Chloride of sodium, 1 5 -060
Phosphate of soda, -i ; 4*267
Phosphate of lime, . ' 0-209
Acetate of soda, '*- 2-770
Urea with colouring matter, 23-640
52-489
The rest of the weight consisted of water together with a free
acid, which may be the lactic.*
But by far the most numerous set of experiments on the con-
stitution of urine has been made by M. Lecanu. His object was
to determine the quantity of urine voided in twenty -four hours,
its specific gravity, and the weight of the urea, uric acid, and salts
which each urine contained. Before giving the table of his re-
sults, it will be worth while to state the general facts brought to
light by his numerous experiments. They may be stated very
shortly.
1. The urine of young men has usually a higher specific gra-
vity than that of old men or infants.
2. The quantity of urea voided in twenty-four hours is very
different in different individuals. One man, for instance, voided
509*3 grains, and another only 185*3 grains.
3. But in the same individual the quantity of urea voided in
twenty-four hours does not vary much, as will appear from the
following table of Lecanu :f
In A,J it varied from 334-9 grains to 478-4 grains.
B, . 360-4 . 478-4
* Records of General Science, ii. 13. f Jour, de Pharmacie, xxv. 746.
% These letters refer to the individuals whose urine is given in a subsequent
table.
URINE. 471
C, . 334-9 . 457-5
D, , 416-7 . 463-0
E, . 416-7 . 509-3
H, . 154-3 . 185-2
4. When the aqueous portion of the urine is increased, the
quantity of urea voided does not undergo a corresponding in-
crease.
5. The quantity of urea does not bear a constant ratio to the
specific gravity of the urine.
6. The quantity of uric acid voided in twenty-four hours was
found to vary from 1-373 grains to 14-307 grains.
7. Healthy urine contains from TJ2 to Tou5stn °f its weight
of uric acid.
8. The uric acid voided does not bear a constant ratio to the
quantity of urine.
9. The quantity of fixed salts in urine varies in twenty-four
hours from 378 grains to 74-8 grains.
10. The earthy phosphates voided in twenty-four hours were
found to vary from 30*25 to 0'447 grains. There is no difference
between the quantity of these salts in the urine of infants and of
young men ; but the quantity in the urine of old persons is sen-
sibly less.
11. The quantity of common salt in urine voided in twenty-
four hours varies from 116-5 to 0-247 grain.
12. The quantity of sulphuric acid in urine voided in twenty-
four hours varies from 57*5 to 15*25 grains.
13. The quantity of phosphoric acid in the phosphate of soda
and ammonia contained in urine voided in twenty-four hours, va-
ries from 25-37 to 0-17 grain.
From these facts Lecanu has drawn the following conclu-
sions : —
1. In the same individual the urea is secreted in equal quan-
tities in equal times.
2. Uric acid, also, in the same individual, is secreted in equal
quantities in equal times.
3. The secretion of urea and uric acid varies very much in dif-
ferent individuals during equal times.
4. The variable quantities of urea which different individuals
secrete during equal times, bear a constant ratio to the sex and
472
LIQUID PARTS OF ANIMALS.
age of the individuals. They are greater in men in the vigour
of life than in women in the same vigour of life. They are
greater in middle-aged women than in old persons or infants.
5. The fixed constituents of urine not driven off by heat,
namely,
The earthy phosphates,
Common salt,
The alkaline sulphates and phosphates,
are secreted in variable quantities, having no relation to the sex
or age, by different individuals, and also by the same individuals
at different times.
The following table, exhibiting the result of M. Lecanu's ex-
periments, conveys a great deal of important information in a
small compass :
No. of Urine void- Uric acid in Urea in 24 Mucus voided
experi- ed in 24 Sp. gravity 24 hours hours in in 24 hours
ments. hours in gr. of urine. in grains. grains. in grains.
1
14168
1-0301
10-63
420 44\
2
14284
1-0309
24-31
365-85
3
14908
1-0316
19-83
403-02
4
17362
1-0163
12-16
427-68
5
11456
1-0186
14-21
437-50
6
12084
1-0309
17-68
423-77
7
18828
1-0265
16-95
478-98
8
13828
1-0265
11-38
410-41
9
13705
1-0272
14-23
413-85
10
13226
10301
13-75
462-62
11
15201
1-0272
19.44
483-41
12
25680
1-0238
9-75
436-37
17.44
13
15804
1-0301
14-38
452-23
14
14615
1-0301
9-94
40283
15
14090
1-0238
7-90
373-39
16
14001
1-0301
11-77
422-79
17
17486
1-0163
20-63
481-93
18
13967
•0301
12.02
473-75
19
14507
0316
12-47
422-88
20
14695
•0309
13-78
466-23
21
14229
0265
2361
422-38
22
13797
•0301
18-21
394-87
23
16791
1-0275
20-48
462-76
24
14646
1-0301
19-48
395-80
26-54
* Jour, de Pharmacie, xxv. 758.
URINE.
473
No. of Urine void- Uric acid void- Urea in 24 Mucus voided
experi- ed in 24 Sp. gravity ed in 24 hours hours in in 24 hours
ments. hours in gr. of urine. in grains. grains. in grains.
19-60
25
17578
1-0386
17-58
462-60
26
'13920
...
19-00
360-50
27
15279
1-0275
8-91
372-57
28
15495
1-0275
20-16
459-92 '
29
13411
1-0386
17-98
437-67
30
12686
1-0316
21-82
376-26
31
12485
1-0386
18-74
357-35
32
16791
1-0267
14-04
'
33
60575
1-0107
419-20
34
48845
1-0137
...
465-89 /
35
33150
1-0117
23-35
456.82 r
36
31452
1-0195
466 -80J
37
26437
1-0232
5-82
501-06.
38
25897
1-0225
6-99
480-28]
39
22162
1-0210
3-78
446-35 \
40
26885
1-0172
4-85
484-63 /
41
29415
1-0180
2-36
467-70 1
42
29817
1-0180
4-17
426-63'
43
31422
1-0210
4-40
283 -09 v
44
35048
1-0217
3-50
371-47
45
24801
1-0230
8-92
379-90
46
30125
1-0208
4-22
383-03
47
33798
1-0225
5-54
447-82
48
34778
1-0180
3-47
331-84
49
29554
1-0202
7-08
235-00
50
28396
1-0195
2-84
179-95
51
30712
1-0195
8-21
248-66
52
30249
1-0217
13-89
272-70 j
53
8812
1-0217
464
92-01 .
54
10957
1-0207
5-48
92-91
55
10741
1-0202
6-23
96-02
56
8519
1-0202
3-92
72-23
57
9291
1-0172
3-54
60-35
58
11760
1-0180
3-06
87 -27/
59
10155
1-0202
3-86
161-46 x
60
61
16050
12346
1-0149
1-0189
2-25
3-70
187-13 f
183-22J
62
...
1-0100
1 94
189-26*
25.16
4-81
D.
E.
5-86
F.
•00
G.
II
474
LIQUID PARTS OF ANIMALS.
No- of Urine void- Uric acid void- Urea in 24 Mucus voided
experi- ed in 24 Sp. gravity ed in 24 hours hours in in 24 hours
ments. hours in gr. of urine. in grains. grains. in grains.
63
28057
1
•0187
6-71
297-51 V
64
18612
1
•0208
10-79
276-22
65
23782
1
•0195
5-89
252-08
66
17748
M
•0232
7-45
262-57
67
17205
1
•0217
6-22
238-18
5-79
68
15927
1
•0202
6-05
208-14
69
23665
1
•0224
7-92
343-54
70
3.1560
* 1
•0144
7-25
230 -90/
71
11667
'•I
•0223
6-76
173-16 <
1
72
8411
1
•0253
7-08
187-22 ]
. 2-08
73
8257
!
•0238
7-10
153-19]
r
74
14430
1
•0238
11-25
309-61 1
,
75
11651
7-90
370-53 j
i
76
16822
'1
•0268
10-76
436-86 j
- 4-81
77
14815
t
•0208
6-53
290 -54 J
78
9661
1
•0227
4-24
245-56^
79
80
14584
12578
0241
•0208
10-50
6-28
340-10 |
235-97
- 0-45
81
8102
•0324
5-66
266 -24 J
82
15232
•0202
2-75
193-70 ^
83
84
85
15680
8441
10417
1
1
•0187
•0215
•0230
1-88
3-87
1-66
216-10 |
219-20
253-73 J
i
86
10787
I
•0230
5-60
161-26-j
87
88
89
10390
9630
8581
1
1
v. i
•0238
•0238
•0268
5-17
4-31
1-37
246-53 1
254 -09 (
209-15J
Quantity
- imponde-
rable.
90
3503
i
•0245
0-96
65-44 \
91
3472
i
•0215
0-89
57-26
92
5016
i
•0238
1-08
81-80J
93
4275
1-0227
2-47
K.
L.
M.
81-80
To understand this table fully, the following observations will
be necessary : —
1. The urine A, from 1 to 12 inclusive, was voided by a young
man of twenty years of age, of a lymphatic temperament, lead-
ing an active life, and using an abundant and varied diet.
2. The urine B, from 13 to 24 inclusive, was voided by a young
URINE. 475
man of 22, of a good constitution, of a sanguine temperament,
leading the same life, and living in the same way as A.
3. Urine C, from 25 to 32 inclusive, was from a man aged
38 years, of a good constitution, of a lymphatico-sanguine tem-
perament, leading an active life, and using an abundant and va-
ried diet.
4. Urine D, from 33 to 36 inclusive, was from a man of 43
years of age, of a good constitution, of a lymphatico-sanguine
temperament, confined to bed from a rupture of the perineum.
His food was soup in the morning, meat and soup at noon, soup,
meat, and vegetables at five P. M., and from twelve to eighteen
ounces of wine daily. When thirsty, he drank barley-water
sweetened with honey.
5. Urine E, from 37 to 42 inclusive, from a man of 35 years
of age, of an athletic constitution, a bilious temperament, con-
fined to his chamber in consequence of a fracture of one of the
clavicles. His food was similar to that of D.
6. Urine F, from 43 to 52 inclusive, from a man aged 38
years, of a good constitution, a lymphatic temperament, taking
abundant and varied nourishment, and a good deal of exercise.
7. Urine Or, from 53 to 58 inclusive, voided by an old man of
86 years of age, of a sanguine temperament, free from infirmity,
and living well.
8. Urine H, from 59 to 62 inclusive, voided by an old man of
85, of a good constitution, a sanguine temperament, his urinary
organs sound, and living well.
9. Urine I, from 63 to 70 inclusive, voided by a woman of 28
years of age, of a sanguine temperament, of a good constitution,
using an abundant and varied diet and moderate exercise.
10. Urine J,from 71 to 73 inclusive, from a woman of 43, of
a good constitution, a bilious temperament, subjected to a good
alimentary regimen.
11. Urine K, from 74 to 77 inclusive, from a girl aged 19, of
a good constitution, a lymphatico-sanguine temperament, sub-
jected to a good alimentary regimen.
12.' Urine L, from 78 to 81 inclusive, from a girl of 19, of a
good constitution, a lymphatic temperament, and well fed.
13. Urine M, from 82 to 85 inclusive, from a boy aged 8 years,
in robust health, of a sanguine temperament, and confined to
bed from a wound in the leg.
476 LIQUID PARTS OF ANIMALS.
14. Urine N, from 86 to to 89 inclusive, from a boy of 8
years, of a good constitution, and a sanguine temperament, con-
fined to bed for a phymosis.
15. Urine O, from 90 to 92 inclusive, from an infant of 3
years, a robust constitution, and a sanguine temperament.
16. Urine P, No. 93, from a child of 4 years, of a good size,
and a lymphatic temperament.
17. The whole of the urine voided by the children O and P
could not be collected. M. Lecanu conceives that the half of it
was lost.
18. The temperature at which the specific gravity of the urine
was taken varied from 68° to 46°, but most commonly it was be-
tween 50° and 60°.
19. The greatest quantity of urine voided in twenty-four hours
was No. 33. It amounted to 60575 grains, or 8-65 pounds avoir-
dupois, but in four days the quantity was reduced to 31452
grains, or 4-49 pounds avoirdupois. The smallest quantity[(ex-
cept that of infants) was No. 73, 8257 grains, or 1-18 pounds,
voided by a woman of 43 years of age.
20. The highest specific gravity was 1*0386, and the lowest,
1-0100.
MM. Cap and Henri are of opinion that urea exists in urine
in the state of lactate of urea, and they have shown by experi-
ments, which appear conclusive, that healthy urine actually con-
tains lactate of urea.* But it would be difficult to prove that all
the urea in healthy urine is in the state of lactate.
Dr Alfred Becquerel f has lately analyzed a great number of
urines, both from individuals in health and disease. The follow-
ing table exhibits the mean quantity, the specific gravity, and the
relative constituents of healthy urine deduced from the analysis
of the urine of eight healthy individuals, four males, and four fe-
males :
In males. In females.
Mean quantity in twenty-four hours, . 2-794 Ibs. 3-024 Ibs.
Mean specific gravity, >,. . 1-0180 1-01512
Mean quantity of water, .•'.' ;• 2-7070 2-948
Do. of solid constituents, ." 0*0870 0-0754
Do. of urea, . ., . 0-0386 0-03433
Do. of uric acid, . . 0-0010 0-00122
* Jour, de Pharm, xxvii, 355. t Semeiotique des Urine, p. 7.
3
URINE. 477
In males. In females.
Mean of fixed salts capable of ignition, 0-0214 0-01855
Do. of organic salts, . . 0-0260 0-02130
Means, supposing the urine to weigh 1000.
Mean water, . . 968-815 971-935
solid constituents, . 31-185 28-066
urea, . . . 13-838 12-102
uric acid, ""*• . 0-557 0-398
fixed salts, ,% . 8-426 6-919
organic salts, \' . 9-655 8-647
The fixed salts were chlorides, phosphates, and sulphates of lime,
soda, potash, and magnesia. The organic salts were lactate of
ammonia, lactic acid, colouring matter, extractive matters, sal-
ammoniac, and perhaps lactate of urea.
Such are the properties, and such the constituents of human
urine in a state of health. But this excretion is singularly modi-
fied hy disease, and the changes to which it is liable have at-
tracted the attention of physicians in all ages, as serving to point
out the state of the patient, and the progress of the disease under
which he labours. It is greatly to be regretted that but few ac-
curate chemical examinations of the urine of individuals labour-
ing under particular diseases have yet been made. The few ge-
neral observations that have been made by medical men are the
following : —
M. Alfred Becquerel has made many analyses of diseased
urine to determine the alterations which take place in its consti-
tuents. The following abstract exhibits the most important facts
which he determined :
1. The quantity of uric acid is augmented by fever and by
functional disorders, such as diseases of the heart, lungs, liver,
&c. When it is superabundant, the urine deposits a sediment
of uric acid. It is diminished in chlorosis, anemia, great prostra-
tion of strength :
Mean normal quantity in 24 hours, sp. gr. 1-016437
water in 24 hours, . . 1-302 Ibs.
uric acid in do. . . 0-00123 Ibs.
Mean excess, . . . 1-021654
water in 24 hours, . . 1*441 Ibs.
uric acid in do. . . 0-0023 Ibs.
Mean deficiency, . . . 1*011855
water in 24 hours, . ' > .-'• 2-3832 Ibs.
uric acid in do. 0-00048 Ibs.
478 LIQUID PARTS OF ANIMALS.
2. The urea seldom exceeds the normal quantity. It is often
deficient.
Normal quantity.
Sp. gr. 1-01656.
Water in 24 hours, . 2-8275 Ibs.
Urea in 24 hours, . 0-03646
(1.) In erysipelas, fever, bronchitis, &c.
Sp. gr. 1-021914.
Water in 24 hours, . 1-5394 Ibs,
Urea in do. . ' . 0-0198
(2.) Pale urine in chlorosis, anemia, prostration of strength
from loss of blood, tedious diseases, &c.
Sp. gr. 1-011837.
Water in 24 hours, . 2'56 Ibs.
Urea in do. . 0-01543
(3.) Urine from persons exhausted by disease, excessive bleed-
ing by leeches, &c.
Sp. gr. 1-01488.
Water in 24 hours, . 1-3116 Ibs.
Urea in do. . 0-01084
3. Fixed salts. — The variation in the quantity of fixed salts re-
sembles that of urea, as will appear by the following statement :
(1.) Normal urine.
Sp. gr. 1-01656.
Water in 24 hours, . 2-8275 Ibs.
Fixed salts in do. . 0-01997
(2.) In fevers with great prostration of strength, diminished
urea and water.
Sp. gr. 1-022218.
Water in 24 hours, . 1-3696
Fixed salts in do. . 0-01157
(3.) In chlorosis, anemia, debility from evacuation.
Sp. gr. 1-011063.
Water in 24 hours, . 2-153 Ibs.
Fixed salts in do. " ' :l " 0-0094
(4.) In fever with functionary disorders. Water diminished,
Sp. gr, 1-024952.
Water in 24 hours, V°; 1-5346 Ibs.
Fixed salts in do. •[;* 0-00968
(5.) In the same diseases. Quantity of water not diminished,
URINE. . 479
Sp. gr. 10-11550.
Water in 24 hours, . 2-6704 Ibs.
Fixed salts in do. . 0-007485
(6.) In anemia, chlorosis, jaundice.
Sp. gr. 1-016100
Water in 24 hours, . 2-6418
Fixed'salts in'do. . 0-02314
When much water is thrown into the system, all the consti-
tuents of urine are increased.
4. Organic salts, &c.
( 1 . ) Normal quantity.
Sp. gr. 1-01656.
Water in 24 hours, . 2*8275 Ibs.
Organic salts in do. 0-0236
(2.) In fever with functional disorders,
Sp. gr. 1-020740.
Water in 24 hours, . 1-5943 Ibs.
Organic salts in do. . 0-021656
(3.) In similar diseases with great debility which diminishes all
the constituents of urine.
Sp. gr. 1-014952.
Water in 24 hours, . 1-5346
Organic salts in do. . 0-0156
(4.) In similar disorders with diseases of the heart or liver,
Sp.gr. 1-010500.
Water in 24 hours, . 2-8336
Organic salts in do. . 0-02088
(5.) In extreme weakness, anemia, chlorosis, long diseases.
Sp. gr. 1-012390
Water in 24 hours, . 2-3691 Ibs.
Organic salts in do. . 0-0178
The urea in urine is often changed into carbonate of am-
monia.
1. In dyspepsia, according to Thenard, the urine putrefies
very rapidly, and is copiously precipitated by the infusion of nut-
galls.
2. In iriflammatorif diseases the urine is of a red colour, scan-
ty, and peculiarly acrid. It deposits no sediment on standing,
but with corrosive sublimate it yields a copious precipitate.
480 LIQUID PARTS OF ANIMALS.
3. In slow nervous fevers the urine, according to Fromherz
and Gugert,* is dark-coloured, and deposits a yellowish red se-
diment, consisting of uric acid with a little colouring matter and
mucus. The urine contains very little urea, less phosphate of
lime than usual, but a great deal of phosphate of magnesia.
Mr Macgregor found the quantity of urea passed in fever
and small-pox nearly the same as in health.
4. In gout, according to Fromherz and Gugert,f the urine,
some time before the paroxysm, was found to contain no uric
acid and very little phosphates. The urine of another patient
voided, just before the paroxysm, was also destitute of uric acid,
but contained more than usual of the phosphates. During the
fit, (as in other fevers,) the free acid in urine diminishes and dis-
appears. The uric acid augments much during the fit. This is
evident from the deposition of chalk stones in the joints of gouty
patients, which Dr Wollaston showed to consist of urate of
5. During jaundice, the urine has an orange-yellow colour,
and communicates the same tint to linen. Muriatic acid some-
times renders this urine green, and thus detects in it the matter
of bile. In gout the urine sometimes contains a yellow^ matter,
similar to what Thenard called the yellow matter of bile. This
substance is only suspended, and may be separated by the filter.
Tiedemann and Gmelin found that the urine of patients labour-
ing under jaundice is precipitated yellow by the sulphate of iron,
the perchloride of iron, the protochloride of tin, the acetate of
lead, the protonitrate of mercury, and corrosive sublimate. Sul-
phate of copper throws down a dirty green precipitate.
Mr Macgregor found the urea passed daily in a well-marked
case of jaundice to be 217 grains. Specific gravity of urine
1*012. In another case, urea, 325 grains, specific gravity of urine,
1'020. In a third, urea, 315 grains, specific gravity of urine,
1-012.
6. In general dropsy or anasarca, the serum of the blood mix-
es with the urine, and renders it albuminous. In such cases it
becomes milky when heated or when mixed with acids. If we
add acetic acid, and then drop in prussiate of potash, a white pre-
cipitate falls. It precipitates also with corrosive sublimate.
* Schweigger's Jour. 1. 205. f Ibid. p. 206.
t Phil. Trans. 1797, p. 386.
URINE. 481
In dropsy from diseased liver, the urine in general is not al-
buminous, but it is scanty, high-coloured, and deposits a pink
sediment.
As the quantity of albumen increases in dropsical urine, that
of the urea diminishes, and is said even to disappear ; though
I have never examined any dropsical urine in which I was not
able to find traces of urea,
7. During hysterical paroxysms the urine usually flows abun-
dantly, it is limpid and colourless, though the colouring matter is
not absolutely wanting. For when sufficiently concentrated the
usual colour of urine begins to be perceptible ; and I have always
been able to detect in it the presence of urea ; though the quanti-
ty is certainly much smaller than usual.
It is well known that the most usual medicine administered
during chlorosis is protoxide of iron, prepared in various ways.
It has been generally admitted by physiologists, that the iron
passes into the system, and is employed in completing the glo-
bules of the blood which are defective in that disease, and that
the surplus is carried off by the urine. But M. Gelis has shown
that this plausible explanation is not well founded. He examin-
ed the urine of 80 patients labouring under chlorosis, and all
under a course of iron preparations ; but in none of these urines
could the least trace of iron be detected.*
8. In syphilis the urine of a man who had been taking mer-
cury by means of the blue ointment, was found by Dr Cantu to
contain mercury. He mixed the precipitate from the urine with
carbonate of potash and charcoal powder, and distilled at a red
heat, globules of mercury were found in the receiver.f Cheval-
lier, who examined the urine of a syphilitic patient while under a
course of mercury, found it milky, of a slightly ammoniacal smell,
and giving out ammonia and sulphuretted hydrogen. It was
mixed with clots of blood, and of course contained all the sub-
stances that exist in that complicated liquid, The constituents
of urine could also be detected.:]:
9. The urine in a catarrhus vesica was examined by Fromherz
and Gugert.§ It was whitish and very muddy, had an acid re-
* Jour, de Pharm. xxvii. 261. t Ann. de Chim. et de Phys. xxvii. 335.
\ Jour, de Chim. Med. i. 179. § Schweigger's Jour. 1. 204.
nh
482 LIQUID PARTS OF ANIMALS.
action, and deposited a sediment consisting entirely of mucus
of the bladder, They could find no trace of uric acid ; but the
other constituents were present in their usual proportions.
I have seen cases seemingly connected with catarrhus vesicse
in which the urine when voided was usually alkaline and muddy,
and had an excessively disagreeable smell. But I never had an
opportunity of examining such urine chemically. The urine could
be completely evacuated only by means of the catheter.
When urine contains pus it is muddy or soon becomes so. It
gradually deposits a sediment and becomes transparent. The
sediment is white, opaque, and in clots. When treated with
ether it gives out a great deal of fatty matter. When mixed
with ammonia it becomes gelatinous. It burns, when dried, with
a vivid flame. The urine when heated deposits albumen. This
urinary portion will be alkaline if the pus exists in considerable
quantity.
When pus is mixed with urine, the conversion of the urea in-
to carbonate of ammonia is hastened.
10. But the disease in which the urine changes its nature most
remarkably is diabetes. There are two species of this disease ;
namely, diabetes insipidus and diabetes mellitus. In the first the
urine is nearly tasteless ; in the second, it is sweet, containing a
considerable quantity of sugar of grapes.
In diabetes insipidus the quantity of urine is greatly augment-
ed ; but it is colourless and tasteless. The specific gravity of the
urine is low. In two cases treated in the Glasgow Infirmary,
Mr Macgregor found the specific gravity to vary from 1 -003 to
1'005. The urea voided daily in these two cases was 310 and
400 grains. Mr Macgregor does not mention the quantity of
urine voided daily. Opium was found to palliate but not to cure
this disease.*
Diabetes mellitus (judging from the number of hospital cases),
seems to be a more common disease in Glasgow than in London.
The average number of diabetic patients admitted into the Glas-
gow Infirmary yearly is 5. In this disease the quantity of urine
is greatly augmented, sometimes amounting to 70 Ibs avoirdupois
hi 24 hours. Mr Macgregor mentions a case in the Glasgow
* Macgregor's Experimental Enquiry, p. 11.
URINE.
483
Infirmary, in which the quantity of urine voided daily amounted
to 45 Ibs., while its specific gravity was 1-054. The quantity of
sugar which it contains increases with the specific gravity. The
following table, drawn up by Dr Henry,* from his own experi-
ments, show the quantity of solid matter contained in diabetes
urine of different specific gravities.
Solid extract in a
Solid extract in a
Specific gravity.
wine pint in grs.
Specific gravity.
wine pint in grs.
1-020,
382-4
1-036,
» 689-6
1-021,
401-6
1-037,
708-8
1-022,
420-8
1-038,
728-0
1-023,
440-0
1-039,
747-2
1-024,
. i 459-2
1-040,
766-4
1-025,
478-4
1-041,
785-6
1.026,
. 497-6
7-042,
804-8
1-027,
516-8
1-043,
824-0
1-028,
536-0
1-044,
843-2
1-029,
555-2
1-045
852-4
1-030,
574-4
1-046
881-6
1-031,
593-6
1-047,
900-8
1-032,
612-8
1-048,
920-0
1-033,
632-0
1-049
939-2
1-034,
651-2
1-050
958-4
1-035,
670-4
In this disease the thirst is insatiable, and the appetite vora-
cious. Yet the egesta in general are less than the ingesta. The
following two cases, which illustrate this, are related by Mr
Macgregor in his Experimental Enquiry.
1. A boy, 16 years of age, weighing 5 stones and 2 Ibs.
Specific gravity of urine 1-035. The following table shows the
ingesta and egesta from the 6th December to the 31st December
inclusive :
Ingesta.
Date.
1834.
Dec. 6
7
Q
9
10
11
12
Liquid.
Solid.
TotalT
Ibs.
Ibs. oz.
Ibs. oz.
13
3 0
16 0
6
3 0
9 0
12
2 4
14 4
15
3 1
18 1
10
1 10
11 10
6
1 9
7 9
11
1 12
12 12
Egesta.
^Liquid.
Solid.
Total.
Ibs. oz.
Ibs. oz.
Ibs. oz.
18 0
1 0
19 0
10 0
0 5
10 3
11 6
1 4
12 10
18 0
1 8
19 8
17 6
0 0
17 6
10 0
0 4
10 4
15 0
0 8
15 8
* Annals of Philosophy, i. 29.
484
LIQUID PARTS OF ANIMALS.
Ingesta
Egesta.
Date.
s~~
Liquid.
Solid.
~~^N»
Total.
Liquid.
Solid.
Totah^
1834.
Ibs.
Ibs
oz.
Ibs.
oz.
Ibs.
oz.
Ibs. oz.
Ibs. oz.
Dec. 13
8
2
9
10
9
10
0
0
8
10
8
14
16
3
2
19
2
15
0
2
3
17
3
15
10
2
9
12
9
15
0
0
4
15
4
16
13
2
9
15
9
15
0
0
0
15
0
17
10
1
9
11
9
10
0
0
0
10
0
18
8
2
0
10
0
10
0
2
1
12
1
19
8
2
0
10
0
10
0
2
11
12
11
20
9
2
7
11
7
8
6
1
3
9
9
21
9
2
4
11
4
7
6
0
0
7
6
22
9
2
9
11
4
7
6
1
4
8
10
23
6
1
13
7
13
7
6
1
6
8
12
24
6
2
9
8
9
7
6
2
6
9
12
25
6
3
1
9
10
0
0
0
10
0
26
12
3
1
15
10
0
0
4
10
4
27
12
3
1
15
15
0
0
0
15
0
28
11
3
1
14
12
6
0
4
12
10
29
11
3
1
14
15
0
0
3
15
3
30
11
2
9
11
9
17
0
0
0
17
0
31
12
2
7
14
7
20
0
0
8
20
8
Total, 330 5 344 10
The average quantity of food and drink per day was 12 Ibs. 11
oz. while that of the egesta was 13 Ibs. 4 oz. so that the latter ex-
ceeded the former by the daily average of 9 oz. With a view to
introduce as much azote as possible into the system, a scruple of
nitrate of ammonia was administered thrice a day, and continued
till the 19th, at which date the thirst was considerably dimi-
nished, and the quantity of urine much less, probably in conse-
quence of the animal food to which his diet was restricted.
On the 22d December six drops of creosote were ordered to
be taken in the course of the day. The dose was gradually aug-
mented, and on the 10th of January amounted to sixty drops;
but it irritated the stomach to such a degree that it was found
necessary to stop it.
Ingesta, Egesta.
Date.
Liquid.
Solid.
TotalT^
Liquid.
Solid.
Totah"
1835.
Ibs.
Ibs.
oz.
Ibs. oz.
Ibs.
oz.
Ibs.
oz.
Ibs.
oz.
Jan. 1
7
2
0
9
0
10
0
0
4
10
4
2
11
2
1
13
1
10
1
2
0
12
1
3
13
1
0
14
0
15
6
2
6
17
12
4
10
2
0
12
0
13
0
0
0
13
0
5
11
2
0
13
0
10
0
1
0
11
0
6
6
1
6
7
6
12
3
0
0
12
8
7
9
2
6
11
6
12
0
0
0
12
0
8
6
2
6
8
6
10
2
0
0
10
2
9
10
2
9
12
9
10
0
1
4
11
4
URINE,
485
Ingesta.
Egesta.
Date.
1835.
Jan. 10
11
12
13
x*"
Liquid. Solid.
Ibs. Ibs. oz.
10 29
10 29
9 2 1
7 22
Total.
Ibs. oz.
12 9
12 9
11 1
9 2
X"~
Liquid.
Ibs. oz.
10 4
12 7
11 0
12 3
Solid.
Ibs. oz.
o o
o o
1 0
o o
Total.
Ibs. oz.
10 4
12 7
12 0
12 3
14
10 22
12
2
10
0
0
0
10
0
15
5
1 9
6
9
5
7
1
n
7
2
16
6
9
7
9
5
7
0
0
5
7
17
6
9
7
9
5
7
0
0
5
7
18
9
7
9
4
0
0
0
4
0
19
4
9
5
9
4
0
0
0
4
0
20
4
9
5
9
3
7
1
0
4
7
21
4
9
5
9
3
7
0
0
3
7
22
3
9
4
9
3
7
1
0
4
7
23
4
9
5
9
3
0
0
0
3
0
24
3
9
4
9
2
7
0
0
2
7
25
5
9
6
9
4
0
0
0
4
0
26
5
9
6
9
2
7
0
0
2
7
27
4
9
5
9
' 2
6
1
1
2
6
28
3
9
4
9
2
7
0
0
2
7
29
3
9
4
9
2
6
0
8
2
14
30
2
9
3
9
2
6
1
0
3
1
31
2
9
3
9
2
1
0
0
2
1
Total, 258 233 10
On the 16th of January opium was ordered in grain doses thrice
a-day. After a few days the dose was gradually increased, and
on the 31st of January the quantity amounted to half a-drachm
daily. The urine was now strongly alkaline, containing car-
bonate of ammonia, but no urea. It is probable that the urea
had been decomposed, and carbonate of ammonia formed before
the urine was voided. The patient sweated copiously, and his
weight was 2 Ibs. greater than when he entered the hospital.
The thirst was greatly diminished, and the ingesta exceeded the
egesta by about a tenth.
Ingesta.
Date. Liquid.
Solid.
Total.
1835.
Ibs.
Ibs.
oz.
Ibs.
oz.
Feb. 1
3
1
9
4
9
I 2
3
0
2
3
2
3
2
0
9
2
9
4
3
0
9
3
9
5
2
0
9
2
9
6
2
1
9
3
9
7
3
1
9
4
9
8
4
1
9
5
9
9
3
1
9
4
9
10
2
0
9
2
9
11
2
1
9
3
9
iquid.
Solid.
Total.
s. oz.
Ibs. oz.
Ibs. oz.
2 0
0 0
2 0
0
0 0
1 0
0
0 0
1 0
0
0 0
1 0
0
0 2
1 2
0
0 4
1 4
2 2
0 0
2 2
2 2
0 0
2 2
2 4
0 4
2 8
2 0
1 4
3 4
2 1
0 0
2 1
486
LIQUID PARTS OF ANIMALS,
Ingesta.
Egesta.
Date Liquid. Solid.
Total.
1835.
Ibs. Ibs. oz.
Ibs.
oz.
Feb. 12
2 1 9
3
9
13
2
9
3
9
14
2
9
3
9
15
3
9
4
9
16
O
0
2
0
17
3
9
4
9
18
3
9
3
9
19
3
2
4
9
20
3
2
4
2
21
3
9
4
9
22
3
9
4
9
23
3
9
4
9
24
4
2
5
2
25
6
9
7
9
26
6 29
8
9
27
6 22
8
2
28
6 1 9
7
9
r"
Liquid.
Solid.
Total.
Ibs. oz.
Ibs.
oz.
Ibs. oz.
2
6
0
0
2
6
2
0
0
0
2
0
2
1
0
4
2
5
2
1
0
0
2
1
2
8
2
8
5
0
2
0
0
0
2
0
2
0
0
4
2
4
2
3
0
0
2
3
3
0
0
0
3
0
3
1
0
0
3
1
3
4
0
0
3
4
8
5
0
0
3
5
3
0
0
2
3
2
3
0
0
1
3
1
5
0
0
1
5
1
9
0
0
4
9
4
9
0
0
0
9
0
Total, 129 4 83 4
The opium was gradually increased, and on the 24th of Febru-
ary amounted to a drachm in 24 hours. The symptoms which
usually attend opium eating made their appearance. Though the
quantity of urine was so greatly diminished, its specific gravity
was as high as 1 -032. It did not taste sweet, and yet it contain-
ed a good deal of sugar. The urea was so abundant, that when
nitric acid was added, crystals of nitrate of urea appeared with-
in ten minutes. The opium was discontinued on the three last
days of the month. The thirst and quantity of urine immediate-
ly increased.
Ingesta. Egesta.
Date. Liquid. Solid.
1835. Ibs. Ibs. oz.
March 1 5 22
Total.
Ibs. oz.
7 2
2
6 1 9
7
9
3
3 1 2
4
2
4
5
2
6
2
5
4
9
5
9
6
3 1
9
4
9
7
3 ,J
9
4
9
8
3
9
4
9
9
4
2
5
2
10
5 ,
9
6
9
11
5
9
6
9
12
5
9
6
9
13
4 ",
9
5
9
14
3
9
4
9
15
3
9
4
9
16
5
9
6
9
17
5 1 9
6
9
Liquid.
Solid.
Total.
Ibs.
oz.
Ibs.
oz.
Ibs.
oz.
5
0
0
0
5
0
4
0
1
2
5
2
2
0
0
0
2
0
4
1
0
0
4
1
2
6
2
8
4
14
6
2
0
0
6
2
4
0
0
0
4
0
4
1
1
3
5
4
2
3
0
0
2
3
2
6
0
4
2
10
2
6
0
6
2
12
2
2
0
0
2
2
2
1
0
0
2
1
2
8
1
2
3
10
2
9
0
0
2
9
2
3
0
8
2
11
3
6
0
0
3
6
URINE.
487
Ingesta.
Egesta.
Date.
Liquid.
Solid.
Total.
1834.
Ibs.
Ibs.
oz.
Ibs.
oz.
Mar.
18
6
2
1
8
1
19
7
2
1
9
1
20
7
1
9
8
9
21
7
1
9
8
9
22
1
9
8
9
23
7
1
9
8
9
24
1
9
8
9
25
7
1
9
8
9
26
6
I
9
7
9
27
6
2
6
8
G
28
6
2
6
8
6
29
7
2
6
9
6
30
7
2
6
9
6
31
7
2
6
9
6
Liquid.
Solid.
Total.
Ibs.
oz.
Ibs.
oz.
Ibs
!. OZ.
4
0
0
3
4
3
3
6
0
0
3
6
3
4
0
6
3
10
4
2
0
0
4
2
5
0
0
4
5
4
6
0
0
0
6
0
6
4
0
6
6^10
4
6
0
0
4
6
7
0
0
0
7
0
7
6
1
5
8
11
7
4
0
0
7
4
7
9
0
2
7
11
8
0
0
0
8
0
8
2
0
0
8
2
Total, . 220 0 Total, . 148 0
Towards the end of the month of March the opium was dis-
continued, and this was followed by a return of the original symp-
toms. The patient was dismissed shortly after. The quantity
of urine was daily 8 Ibs. It had a sweetish taste, and fermented
readily with yeast. At the end of March his weight was 5 stones
and 3 Ibs.
In the second case given by Mr Macgregor, the symptoms and
treatment were nearly the same. It is unnecessary, therefore,
to state it at length.
Mr Macgregor found urea in diabetic urine to fully as great
an amount as in healthy urine. One patient passed daily 14-65
Ibs. of urine of specific gravity 1*039. It contained 101 3-D
grains of urea. Another passed 30 Ibs. of urine of specific gra-
vity 1 -045. This urine contained 945 grains of urea. A third
passed daily 40 Ibs, of urine of specific gravity 1-034, and con-
taining 810 grains of urea. A fourth passed 25 Ibs. of urine of
specific gravity 1-050, and containing 512-5 grains of urea. Now
the greatest quantity of urea passed in twenty-four hours in the
tables of Lecanu given above, and containing 93 cases, was 50T06
grains.
The sugar which exists in such quantity in the urine of dia-
betic patients is not generated by the kidneys, but by the organs
of digestion. Mr Macgregor found it abundantly in the blood,*
* Vauquelin had long ago examined the blood of a diabetic patient without
finding any sugar in it. (Jour, de Physiologic, iv. 257.) This also had been
done by Dr Wollaston. The method employed by these chemists had not been
sufficiently delicate.
488 LIQUID PARTS OF ANIMALS.
and also in the saliva, sweat, and stools of diabetic patients. The
abnormal state of the digestive organs gives origin to the forma-
tion of this sugar. No medical treatment hitherto tried has been
capable of removing the disease. Animal food seems to dimi-
nish the thirst and urine by bringing on nausea. Opium palli-
ates but does not remove the disease. It is obvious from the
facts above stated that there is no want of urea in diabetic urine.
Hence it is very probable that the introduction of urea into the
stomach of diabetic patients, as has been proposed by some me-
dical men in France, would not contribute to remove the dis-
ease.
11. Urine during cramp of the stomach. — This urine was ex-
amined by M. L. Gmelin.* It was clear, brown in mass, but
yellow in thin layers. With muriatic acid it formed a brown
mixture, with much nitric acid a clear red mixture, with a small
quantity of that acid a violet- coloured precipitate. This preci-
pitate was chiefly uric acid. On standing twenty-four hours the
urine deposited a rose-red sediment. The urine contained uric
acid, purpuric acid, and altered choleic acid.
12. Intoxicating urine. — It has been long known that the Tar-
tars make an intoxicating liquor by infusing the Agaricus musca-
rius in koumiss, or fermented mare's milk ; and that the intoxi-
cating properties of this agaric pass into the urine of those who
have taken it into the stomach. Langsdorf, in his travels among
the KorcEken, has remarked that the urine is even more intoxi-
cating than the prepared koumiss itself. It is much sought af-
ter by other persons, who intoxicate themselves by drinking it
Indeed, such is the persistence of this intoxicating quality, that
urine voided by five or six individuals in succession still re-
tains it.f
13. In certain cases females, and sometimes males, have been
observed to pass urine which had the appearance of milk. On
standing a cream was formed on its surface, and it was found to
contain a notable proportion of casein. :f
14. Medical men have repeatedly made mention of blue urine,
deriving its colour from a blue substance held in suspension in
it, quite different from Prussian blue. Gornier and "? .Ions found
this blue colouring matter a little soluble in water. Neither
acids nor alkalies alter its colour ; but nitric acid destroys it.§
* Ann. der Pharm. xxvi. 359. f Jour, de Pharmacie, xii. 477.
\ Caballe, Ann. de Chim. iv. 64. § Jour. Gener. de Medecine, Ixxii. 174.
URINE. 489'
Braconnot met with a case of blue urine passed by a girl of fif-
teen years of age, enjoying pretty good health, though subject to
stomach complaints.* During a paroxysm of pain in the stomach
she vomited and voided urine. Both liquids had so deep a blue
colour that they appeared almost black. The blue pigment
which this urine contained had neither taste nor smell. It was
in a state of very minute division, and had a deeper colour than
Prussian blue. When heated it gave out carbonate of ammonia
and an empyreumatic oil. It was slightly soluble in water and
in boiling alcohol. The alcohol assumed a green colour, and de-
posited on cooling a small quantity of very deep blue pigment,
almost crystalline. When the alcohol evaporated the blue pig-
ment remained, and dissolved in acids with the exception of a lit-
tle fatty matter. The blue pigment is soluble in all acids, even
the oxalic and gallic, and when so dissolved becomes red. When
a saturated solution of this colouring matter in dilute sulphuric
acid is evaporated, we obtain a carmine-red residue, which be-
comes brown when dissolved in water, but resumes its red colour
when the water is evaporated off. The blue matter is slightly
soluble in acetic acid. The solution is brownish-yellow, but
when the acid is driven off, the blue colouring matter is left un-
altered. When the red acid solutions are saturated with an al-
kali, the colouring matter precipitates with its original blue colour.
This blue matter is scarcely soluble in caustic potash, and not at
all in the carbonate of potash.
The urine from which this blue matter had separated let fall
when heated an additional quantity of this blue matter of so deep
a shade that it appeared black, but possessed the properties of the
original blue pigment. Braconnot considers this blue sediment as
a salifiable base, and has distinguished it by the name ofcyanurm.
Marx made some experiments on a blue-coloured urine passed
by Dr Wollring at Gottingen.| He analyzed the sediment, and
states its constituents as follows :
Blue colouring matter, , 29-09
Uric acid, . . 46-80
Earthy phosphates, . 18-19
Mucus, . . 5-92
100-
* Ann. de Chim. et de Phys. xxix. 252. f Schweigger's Jour, xlvii. 487.
490 LIQUID PARTS OF ANIMALS.
The characters of the blue matter differed somewhat from those
described by Braconnot. It was soluble in alcohol, and when
the solution was evaporated, the blue sediment remained without
showing the least tendency to crystallization. It was soluble,
also, in boiling ether. Concentrated sulphuric acid dissolved it
and assumed a blue colour, but muriatic acid did not act upon it.
Nitric acid, when heated, destroyed it, and converted it into Wel-
ter's bitter principle. It was insoluble in caustic alkalies and
their carbonates. When burnt, it left a little phosphate of lime.
15. Urine is sometimes mixed with blood. If the quantity of
blood be considerable, its presence is easily recognized by the
red colour. The globules of blood do not dissolve in urine.
They fall to the bottom, and may be easily distinguished by ex-
amining the sediment through the microscope.
Urine containing blood always holds in solution some albu-
men, which coagulates when the urine is heated or mixed with
nitric acid. Such urine is always alkaline, unless the quantity
of blood be very small. The globules of blood in urine assume
an irregular form, and when treated with ammonia or acetic acid
dissolve completely. M. Lecanu has given the following method
of detecting minute quantities of blood in urine :*
If the urine be ammoniacal it is neutralized by nitric acid,
and raised to the boiling temperature. The albumen coagulates
and falls to the bottom, carrying with it the globules of the blood.
The deposit, is collected on a filter and washed first with water,
and then with alcohol. It is then introduced into a matrass with
alcohol of O842, slightly acidulated with sulphuric acid, and the
liquid raised to the boiling temperature. The deposit, which was
at first reddish-brown, becomes colourless, while the alcohol as-
sumes a brownish colour, which a slight addition of ammonia
changes to red. The alcoholic solution being concentrated leaves
the colouring matter in the state of a black resinous-looking
matter, soluble in acetic ether and ammoniacal alcohol, to which
it gives a red colour, as soon as the alcohol and ammonia are
evaporated. If we calcine this matter, there remains a red ash,
soluble in muriatic acid, and the solution strikes a blue with
prussiate of potash.
16. Dr Marcet, in the twelfth volume of the Medico-Chirur-
gical Transactions, described a singular variety of urine, which
* Jour, de Pharm. xxvi. 206.
URINE. 491
became black soon after it was passed. A portion of this urine
was examined by Dr Prout, who gave the following account of
it:*
The residue remaining after the urine is evaporated to dry-
ness contains no uric acid, and no urea can be detected in it by
the usual tests. Although the addition of dilute acids produced
no immediate change of colour in this urine, yet, on standing
some time, a black precipitate slowly subsided, leaving the super-
natant fluid transparent and but slightly coloured.
The black precipitate was nearly insoluble in water and alco-
hol, whether hot or cold. It dissolved in concentrated sulphuric
and nitric acids, forming a deep brownish-black solution ; but on
adding water the black substance precipitated unaltered. It dis-
solved readily in the fixed alkalies, and in their carbonates ; but
acids precipitated it unaltered. When ammonia was employed
as a solvent, and the excess driven off by evaporating to dryness,
a deep-brown matter remained, composed of the black matter
and ammonia. This compound was very soluble in water, and
when heated with caustic potash, gave out the smell of ammonia.
It would not crystallize. From the aqueous solution of this
brown matter chloride of barium and nitrate of silver threw down
copious brown precipitates ; as did also protonitrate of mercury
and nitrate of lead. Corrosive sublimate produced no immedi-
ate precipitate, and that obtained from acetate of zinc was of a
pale-brown colour.
From these experiments Dr Prout inferred that the urine ow-
ed its black colour to a compound of the black matter with am-
monia. The black matter he considers as an acid, which he dis-
tinguishes by the name of melanic acid. No experiments have
been made to determine the nature of this acid, or the relation in
which it stands to uric acid.
17. Some very cruel experiments were made upon dogs by
M. Collard de Martigny. He starved the poor animals to death.
In the urine of a dog thus treated he could detect no urea.f
The same remark was made by Magendie with respect to the
urine of dogs fed on sugar, gum, or olive oil, which in fact died
of starvation.}
» Annals of Philosophy, (2d series), iv. 71.
•j- Jour, de Physiologic, via- 157. \ Ibid. ii. 487.
492 LIQUID PARTS OF ANIMALS.
But Lassaigne found urea in the blood of a madman who had
fasted during eighteen days.*
According to Martigny, the proportion of albumen in blood
increases by abstinence, while that of fibrin diminishes, and the
quantity of blood is constantly diminishing as long as abstinence
is continued.!
18. Donne observes that, after eating sorrel, the urine was fil-
led with minute crystals of oxalate of Iime4
19. Viscid urine.
MM. Cap and Henry examined a urine to which they gave
that name. It was acid when voided, but soon became alkaline.
It had a light-yellow colour, and was muddy, and a white mag-
ma occupied the greatest part of the liquid, floating by the slight-
est agitation, and depositing itself slowly. A scanty gray sedi-
ment was at the bottom of the vessel. The viscid magma was
separated by the filter. The urine filtered had a specific gravity
of 1 '00691. It was composed of,
Water, :!-;; v *0y Hqai ^i 98-12
Urea, KM hey?^ k^o, ^ri,«, 0-40
Albumen, wy dt.sj 1 . ', .*, $vfi 0'17
Mucus, a'fca thw iui-M> >*&* 0-50
Chlorides of sodium, potassium, ammonium, -\
Urate of ammonia, *&rii -orj V 0-81
Phosphates of soda, ammonia, lime, magnesia, )
Sulphate of soda trace.
Lactate of ammonia trace.
100-00
The viscid magma consisted of fibrin, albumen, and spermatin.§
Such are the characters and constitution of human urine, and
such the changes produced in it by disease, as far as the subject
has been investigated. Much less progress has been made in the
investigation of the urine of the inferior animals. The follow-
ing are the principal facts on this prolific subject that have been
hitherto ascertained :
I. The urine of carnivorous animals is acid, and usually con-
tains salts of ammonia ; the urine of graminivorous animals is
alkaline, and contains carbonates, particularly carbonate of lime.
* Jour, de Chimie Medicale, 1825. f Jour, de Physiol. viii. 165, 169.
\ Comptes Rendus, viii. 805. § Jour, de Pharm. xxiii. 329.
URINE. 493
II. The urine of the monkey, according to Coindet, has a
greenish-yellow colour, and its specific gravity varies from 1 -0045
to 1*0108. It contains a good deal of salts of sulphuric and
phosphoric acids, a great deal of salts of potash, but no uric acid.*
III. The urine of the dog,f according to Tiedemann and Gme-
lin, has a yellowish or greenish-brown colour. It has an acid
reaction ; becomes reddish-yellow, and then green when mixed
with muriatic acid. When mixed with nitric acid, much uric
acid fell, and the urine became green, then blue, and finally
dark-red.J These phenomena show clearly that the urine of the
dog examined contained bile.
IV. The urine of the horse has usually an amber colour.
When voided it is sometimes transparent, sometimes muddy, and
it soon deposits a white precipitate, consisting chiefly of carbo-
nate of lime. Its specific gravity, according to Fourcroy and
Vauquelin, varies from 1*03 to 1*05. The specific gravity of a
specimen examined by Dr Prout was 1-0293.§ That of a horse
experimented on by Boussingault, 1*064.|| The average quan-
tity voided in twenty-four hours was only 2-928 Ibs. He found
in it a greater quantity of urea than in human urine. It was
announced many years ago by Fourcroy and Vauquelin, that the
urine of the horse contains benzoic acid. But Liebig has shown
that the acid contained in the urine of the horse is not the ben-
zoic, but another acid containing peculiar properties, to which he
has given the name of hippuric^ and which has been described
in a former part of this work.**
The constituents of the urine of the horse, as determined by
Fourcroy and Vauquelin, are the following :
Water and mucus, . 94'
Carbonate of lime, . !•!
Carbonate of soda, . 0*9
Hippurate of soda, . 2 -4
Chloride of potassium, . 0-9
Urea, . . 0-7
lOO-Oft
* Biblioth. Univer. xxx. 492. f The gall -ducts of this animal were tied.
\ On Digestion, ii. 4. § Annals of Philosophy, xvi. 150.
|| Ann. de Chim. et de Phys. Ixxi. 128. f Ibid, xliii. 188.
«* See Chemistry of Vegetables, p. 46. ft Mem. de Hnstitut, ii. 431.
494 LIQUID PARTS OF ANIMALS.
Mr Brande, about the year 1806, made some experiments on
the urine of the horse, which are stated by Mr Hatchett in a let-
ter to Sir Everard Home.* He extracted from that urine the
following salts :
Carbonate of lime. Common salt.
Carbonate of soda. Hippurate of soda.
Sulphate of soda. Phosphate of lime.
These saline contents constituted about one-eighth of the weight
of the urine. So that the water, according to this estimate,
amounts only to 87*5 per cent. Chevreul examined the urine
of the horse in 1808, expressly to ascertain whether it contained
phosphate of lime, as stated by Brande. | He could find none ;
but detected magnesia and sulphate of potash.
V. The urine of the ass was examined by Mr Brande in 18064
It was transparent and colourless, gave a green colour to the
syrup of violets, but no carbonate of lime was deposited when
the urine was left at rest. According to Brande, it contained
urea, more phosphate of lime than the urine of the horse, car-
bonate of soda, sulphate of soda, common salt, and probably chlo-
ride of potassium. It contained no ammonia.
VL The urine of the cow has a strong resemblance to that of
the horse. It has nearly the same colour and the same mucila-
ginous consistence. It tinges syrup of violets green, and depo-
sits a mucous matter. On standing, small crystals are formed
on its surfaces. The quantity voided in 24 hours by a cow giving
milk, was found by Boussingault to be 18'13 Ibs., and the milk
18-7 Ibs. The water drank in 24 hours was 132-282 Ibs. The
specific gravity of the urine was 1'035.§ It contains, according
to Rouelle,
Carbonate of potash. Urea.
Sulphate of potash. Hippuric acid ?
Chloride of potassium.
Mr Brande examined this urine in 1806,|| and found its con-
stituents,
* Phil. Trans. 1806, p. 380. f Ann- de Cnim- lxvii- 303-
f Phil. Trans. 1806, p. 380. § Ann. de Chim. et de Phys. Ixxi. 113.
|| Phil. Trans. 1806, p. 378.
URINE. 495
Water, . 65
Phosphate of lime, . 3
Chloride of potassium, \ ^
Sal-ammoniac, . /
Sulphate of potash, . 6
Carbonate of potash, \ ^
Carbonate of ammonia, /
Urea, . . 4
97
He obtained also a quantity of benzoic acid, (probably hippuric
acid,) but considers it as proved, that this acid was formed dur-
ing the process to which the urine was subjected.
VII. The urine of the camel has been examined by Rouelle,
Brande, and Chevreul, The smell resembles that of the cow.
Its colour is that of beer ; it is not mucilaginous, and does not
deposit carbonate of lime. It gives a green colour to syrup of
violets, and effervesces with acids like the urine of the horse and
cow. Rouelle* obtained from it,
Carbonate of potash. Chloride of potassium.
Sulphate of potash. Urea.
Mr Brandej made a set of experiments on the urine of the
camel, at the request of Sir Everard Home, and obtained,
Water, . . 75
Phosphate of lime,
Sal-ammoniac,
Sulphate of potash,
Urate of potash,
Carbonate of potash,
Common salt, . . 8
Urea, o vm . 6
95
Ghevreul examined the urine of the camel on purpose to
ascertain whether the phosphate of lime, stated by Brande as a
constituent, really existed in that urine. :£ He could find no tra-
ces of it, but extracted from the urine of the camel the following
substances :
* Jour, de Med. xl. t Phil- Trans. 1806, p. 376.
Ann. de Chim. Ixvii. 294.
496 LIQUID PARTS OF ANIMALS.
Albumen. A little sulphate of soda.
Carbonate of lime. Much sulphate of potash.
Carbonate of magnesia. A little carbonate of potash.
Silica. Hippuric acid ?
Trace of sulphate of lime. Urea.
Trace of iron. A brown oil, having a strong
Carbonate of ammonia. smell.
Chloride of potassium.
VIII. The urine of the sow was subjected to chemical analy-
sis in 1819, by M. Lassaigne.* It is transparent, slightly yellow,
without smell, and having a disagreeable, but not saline, taste.
The following were the substances extracted from this urine by
M. Lassaigne:
Urea. Sulphate of potash.
Sal-ammoniac. A little sulphate of soda.
Chloride of potassium. Trace of sulphate and carbonate
Common salt. of lime.
IX. The urine of the rabbit was examined by Vauquelin.f
When exposed to the air it becomes milky, and deposits carbo-
nate of lime. It gives a green colour to syrup of violets and ef-
fervesces with acids. Vauquelin detected in it the following sub-
stances :
Carbonate of lime. Chloride of potassium.
Carbonate of magnesia. Urea.
Carbonate of potash. Mucus.
Sulphate of potash. Sulphur.
Sulphate of lime.
X. The urine of the guinea pig was examined also by Vau-
quelin ; though the quantity subjected to analysis was too small
to enable him to make a detailed examination. It became tur-
bid, and deposited carbonate of lime on cooling, gave a green co-
lour to syrup of violets, and was found to contain carbonate of
potash and chloride of potassium ; but neither phosphate nor
uric acid could be detected in it.}
XI. The urine of the rhinoceros was examined by M. Vogel
in 1817. § It was muddy, and let fall on cooling a great quan-
tity of an ochre-yellow matter. Twenty pounds of the urine
* Jour, de Pharmacie, viii. 174.
f Fourcroy's General System of Chemical Knowledge, x. 265.
f Ibid. p. 267. § Schweigger's Jour. xix. 156.
URINE. 497
yielded 6 ounces and 5 drachms of this deposit. It consisted of
carbonates of lime and magnesia with a little iron and silica, and
a small quantity of an animal substance containing azote.
The smell of the urine was peculiar, and had some resemblance
to that of bruised ants. It effervesced strongly with acids. Its
colour after filtration was dark-yellow. Even after filtration it
continued to effervesce on the addition of acids. It very slight-
ly reddened litmus-paper. When boiled it became brown, and
ceased to act on litmus-paper, and hardly became muddy when
mixed with oxalate of ammonia.
This urine contained,
Mucus. Bicarbonate of lime.
Urea. Sulphate of lime.
Sulphuretted hydrogen. Carbonate of magnesia.
Carbonate of ammonia. Silica.
Hippurate of potash ? Iron.
Chloride of potassium.
XII. The urine of the elephant was also examined by M. Vo-
gel.* Its colour was the same as that of the rhinoceros but not
so dark. It gave a green colour to syrup of violets, deposited
less sediment on cooling than the urine of the rhinoceros, and
gave out when heated less carbonic acid and sulphuretted hydro-
gen. Its constituents were similar to those of the preceding
urine. But it contained more mucus, urea, and carbonate of am-
monia, and less carbonate of lime, and carbonate of magnesia,
and no hippuric acid.
XIII. The urine of the beaver has a striking resemblance to
that of herbivorous animals in general. Vauquelin f extracted
from it the following substances :
Mucus. Sulphate of potash.
Urea. Chlorides of potassium and so-
Hippurate of potash ? dium.
Carbonates of lime and Colouring matter.
magnesia. Trace of iron.
Acetate of magnesia.
XIV. The urine of the lion, tiger, hyaena, and leopard, when
quite fresh, reddened litmus-paper ; but speedily becomes neutral
and then alkaline.J It contains uric acid. Vauquelin made
* Schweigger's Jour. xix. p. 162. f Ann. de Chim. Ixxxii. 201.
J Stromeyer, Edin. Jour, of Science, xviii. 356.
i i
4Q8 LIQUID PARTS OF ANIMALS.
some experiments upon the urine of the lion and the tiger, and
obtained results differing from those of Stromeyer.* According
to him it is alkaline at the time of its emission. It contains, he
says, a quantity of ammonia ; but no uric acid nor phosphate
of lime. Vauquelin obtained from it the following substances :
Mucus. Sal-ammoniac.
Urea. Trace of phosphate of lime.
Phosphate of soda. Much sulphate of potash.
Phosphate of ammonia. Trace of common salt.
XV. The urine of fowls, as was first ascertained by Dr Wol-
laston, consists chiefly of uric acid. It seems to be combined with
ammonia, and is mixed with a good deal of animal matter.
XVI. The urine (if that name can be given to a solid excre-
mentitious substance) of the Boa constrictor was found by Dr
Prout to consist almost entirely of urate of ammonia. This fact
being communicated to Dr John Davy while in Ceylon, about
the year 1817, he was induced to examine the excrements of dif-
ferent species of serpents, f When thrown out it has a butyra-
ceous consistence, but becomes hard by exposure to the air. He
found it to consist chiefly of uric acid, probably in the state of
urate of ammonia. The urinary matter of lizards was similar.
That of the alligator, besides uric acid, contains a large portion
of carbonate and phosphate of lime. The urine of turtles was
liquid, containing flakes of uric acid, and holding in solution
a little mucus and common salt, but no sensible portion of urea.
Some experiments on the urine of lizards (Lacerta agilis, Seps
viridis, varius, terrestris, sericeus, c&ruleus, &c.) had been made
by M. Schriebers as early as 18134 He found it to consist of,
Uric acid, . 94
Ammonia, . 2
Phosphate of lime, 3-33
99-33
So that he preceded Dr Davy, and probably also Dr Prout, in
this curious investigation.
* Ann. de Chim. Ixxxii. 198. f Phil- Trans. 1818, p. 303.
J Gilbert's Annalen, xliii. 83.
SEMEN. 499
CHAPTER XIII.
OF SEMEN.
THE liquor secreted in the testes of males, and destined for
the impregnation of the female, is known by the name of semen.
The human semen and the milt of fresh-water fishes alone have
hitherto been subjected to a chemical examination. Nothing is
known concerning the semen of other animals. Vauquelin pub-
lished an analysis of human semen in 1791.* Jordan made some
experiments on it in ISOl.-f- Dr John also examined it, though
I have never seen the paper which he published on the subject
Berzelius likewise has subjected semen to a chemical examina-
tion, J
I. Semen, when newly ejected, is evidently a mixture of two dif-
ferent substances. The one, fluid and milky, which is supposed
to be secreted by the prostate gland ; the other, which is consi-
dered as the secretion of the testes or the true semen, is a thick
mucilaginous substance, in which numerous white filaments may
be discovered. These filaments constitute a peculiar animal
principle, which has been distinguished by the name of spermatin.
Semen has a slight but unpleasant smell, an acrid irritating
taste, and its specific gravity is higher than that of water. When
rubbed in a mortar, it becomes frothy, and of the consistence of
pomatum, in consequence of its enveloping a great number of
air-bubbles. It changes syrup of violets to green, from the un-
combined soda which it contains.
As the liquid cools, the mucilaginous part becomes thready,
and acquires greater consistency, but in about twenty minutes
after its emission, the whole becomes liquid. This liquefaction is
not owing to the absorption of moisture, for it loses instead of
gaining weight ; nor to the action of the air, for it takes place
equally in vacuo.
Semen is insoluble in water before this liquefaction, but after-
wards it dissolves readily in it. When alcohol or chlorine is ad-
ded to this solution, white flocks separate. Alkalies readily dis-
solve the semen, and it is soluble in concentrated sulphuric acid,
* Ann. de Chim. ix. 64. f Crell's Annalen, 1801, i. 461.
\ Traite de Chimie, vii. 558.
500 LIQUID PARTS OF ANIMALS.
and in nitric acid when assisted by heat, but acetic acid only dis-
solves it partially.
Lime disengages no ammonia from fresh semen, but after that
fluid has remained for some time in a moist and warm atmosphere,
lime separates a great quantity from it. Hence ammonia is
formed during the exposure of semen to the air. *
When chlorine is added to semen, a number of white flocks
separate, and the chlorine loses its smell. If the quantity of chlo-
rine be considerable, the semen assumes a yellow colour.
When semen is exposed to the air about the temperature of
60°, it becomes gradually covered with a transparent pellicle,
and in three or four days deposits small transparent crystals,
often crossing each other in such a manner as to resemble the
spokes of a wheel. They are four-sided prisms, terminated by
very long four-sided pyramids. Vauquelin considered them as
crystals of phosphate of lime ; but that salt never crystallizes in
four-sided prisms. It is much more probable that the crystals
are of ammonia-phosphate of magnesia, which assumes the shape
of a rectangular prism with a square base.
If, after the appearance of these crystals, the semen be still
allowed to remain exposed to the atmosphere, the pellicle on its
surface thickens, and a number of white round bodies appear on
different parts of it. These, according to Vauquelin, are con-
cretions of phosphate of lime. They amount, he says, to three
per cent, of the weight of the semen. If at this period of the
evaporation the air become moist, crystals of carbonate of soda,
and doubtless of common salt, appear in the substance. The
evaporation does not go on to complete desiccation unless the air
be very dry and the temperature at least as high as 77°, the resi-
due amounts to one-tenth of the semen. It is translucent like
horn, and brittle.
When semen is kept in very moist air, at the temperature of
about 77°, it acquires a yellow colour like that of the yolk of an
egg ; its taste becomes acid, it exhales the odour of putrid fish,
and its surface is covered with abundance of the Byssus septica.
When dried semen is exposed to heat in a crucible, it melts,
acquires a brown colour, and exhales a yellow fume having the
odour of burnt horn. When the heat is raised the matter swells,
* Vauquelin, Ann. de Chim. ix. 71.
SEMEN. 501
becomes black, and gives out a strong odour of ammonia. If the
residue be lixiviated with water, an alkaline solution is obtained,
which gives crystals of carbonate of soda, and doubtless of com-
mon salt. A little phosphate of lime remains.
The constituents of semen, according to the analysis of Vau-
quelin, are,
Water, . 90
Spermatin, . 6
Phosphate of lime, 3
Soda, . . ]
100
But this analysis was made before chemistry had acquired the
requisite precision. It cannot, therefore, be depended on. In
a previous chapter of this volume, while treating of spermatin,
the more recent experiments of Berzelius on human semen have
been stated.
II. Fourcroy and Vauquelin published a set of experiments on
the milt of the carp in the year 1807,* from which it appears
that the nature and composition of this substance is different .from
that of every other hitherto examined. The milt of this fish, as
is well known, has a whitish colour, a soft consistence, a greasy
feel, and a smell similar to that of fish. It is neither acid nor
alkaline. When triturated with potash, no ammoniacal odour is
exhaled, and it forms with the alkali a thick magma. Thirty
parts of milt mixed with six parts of potash, and a sufficient
quantity of water, and distilled, yielded only traces of ammonia,
coming obviously from some muriate of ammonia, which exists
naturally in the milt. When milt is dried slowly in a moderate
heat, it loses three-fourths of its weight, becomes yellow and
brittle. When heated in a platinum crucible it softens and then
melts, exhaling yellow vapours having the smell of animal oil.
The charcoal formed contains a notable quantity of uncombined
phosphoric acid, together with some phosphate of lime and phos-
phate of magnesia. As the acid did not exist in the milt, it must
have been formed during the combustion ; and hence it follows,
that milt contains a notable quantity of phosphorus as a consti-
tuent.
One hundred and twenty-three parts of fresh milt, cautiously
* Ann. de Chim. Ixiv. 5.
502 LIQUID PARTS OF ANIMALS.
distilled in an earthen-ware retort, gradually heated to white-
ness, furnished the following products: 1. A great deal of
colourless water holding in solution carbonate of ammonia, a good
deal of prussiate of ammonia, and traces of muriate of ammonia ;
2. A transparent oil slightly yellow ; 3. A fluid blood- red oil ;
4. A thick blackish-brown oil ; 5. Crystals of carbonate and
prussiate of ammonia ; 6. A quantity of phosphorus ; 7. A small
quantity of carbonic acid and heavy inflammable air. The char-
coal remaining in the retort amounts to 7^ parts, and contains
no disengaged phosphoric acid.
When milt is triturated in distilled water, a white opaque li-
quid is obtained, which does not become transparent though pas-
sed through the filter. When the liquid is boiled, an albuminous
matter coagulates ; and if the residuary liquid be evaporated
sufficiently, it gelatinizes ; a proof that it contains gelatin. Al-
cohol digested on milt dissolves a substance which possesses the
properties of animal soap. When it is- separated, the milt be-
comes dry and harsh to the feel ; a proof that its unctuosity was
owing to the presence of the animal soap.
Thus it appears that milt contains albumen, gelatin, phospho-
rus, phosphate of lime, phosphate of magnesia, and muriate of
ammonia.
CHAPTER XIV.
OF SYNOVIA.
WITHIN the capsular ligament of the different joints there is
contained a peculiar liquor, intended evidently to lubricate the
parts and to facilitate their motion. This liquid is known among
anatomists by the name of synovia*
The chemical constitution of this liquid has been but imper-
fectly ascertained. It is mucilaginous like the white of egg,
* The word synovia (from tuv and »o», probably from its resemblance to
the white of an egg), is said to have been first used by Paracelsus, and to have
signified the juice which nourishes the different parts of the body. I find the
word synophia used by him in that sense. See his Scholia in libros paragra-
phorum ; de Gutta. Opera Paracelsi, i. 547. Geneva edition.
8
SYNOVIA. 503
ti'ansparent and yellowish or reddish. Its taste is slightly saline,
and its smell similar to that of serum of blood.
1. M. Dupuytren had an opportunity of examining the syno-
via of the knee of a man who was affected with a disease of that
joint. It was viscid, thready, transparent, and slightly reddish.
Its specific gravity was 1-05.* MM. Lassaigne and Boisset ob-
tained from Dr Amussat a small quantity of synovia from the
large joints of several dead bodies, which enabled them to make
some chemical experiments on it.f From the method of extract-
ing it by a sponge, it was necessarily mixed with distilled water.
It was colourless, had a slight smell, frothed when agitated, and
restored the colour of reddened litmus-paper. Nitric acid and
alcohol threw down white flocks, and the infusion of nut-galls oc-
casioned a yellowish-white precipitate. These reagents show the
presence of albumen in human synovia.
When evaporated by a gentle heat, a white pellicle formed on
its surface, which increased in thickness, and at last was preci-
pitated in flocks, which were separated by the filter. The liquid
being evaporated, gave a yellow extract, having a saline and sharp
taste. And cubic crystals gradually formed in it. Alcohol dis-
solved a yellow animal matter. The residue of the alcoholic so-
lution being calcined, yielded chloride of sodium, mixed with a
little chloride of potassium. The portion insoluble in alcohol
dissolved in water, and contained carbonate of soda, and an ani-
mal matter containing azote, the nature of which was not ascer-
tained. They could detect no uric acid in human synovia. The
albumen precipitated contained a little fatty matter.
According to this analysis, human synovia contains,
Albumen.
Fatty matter.
An animal substance soluble in water.
Soda,
Chloride of sodium and potassium.
Phosphate and carbonate of lime.
Dr Bostock made some experiments on the synovia from the
knee of a man. It contained albumen coagulated and half- coa-
gulated, and a mucoso-extractive matter always found in albu-
minous fluid.J
* Jour, de Medecine, Chirurgie, &c. ii. 466.
t Jour, de Pharmacie, viii. 206. f Annals of Philosophy, xii. 121.
504 LIQUID PARTS OF ANIMALS.
2. M. Margueron examined the synovia of the ox in 1792.*
The synovia which he subjected to experiment was from the joints
of the legs, probably the knee-joint ; though that is not stated.
This synovia, when it had just flowed from the joint, was a viscid
semitransparent fluid, of a greenish- white colour, and a smell not
unlike that of frog's spawn. It soon acquired the consistence of
jelly, and this happened whether it was kept cold or hot, and
whether the air had access to it or was excluded. This consist-
ence did not continue long. The synovia soon recovered its
fluidity, while at the same time a thready-like matter was depo-
sited.
It readily mixed with water, and imported to that liquid a por-
tion of its viscidity. When the mixture was boiled it became
milky, and deposited some pellicles, but the viscidity was not di-
minished.
Alcohol precipitates albumen from synovia. Margueron found
the amount of albumen in the synovia which he examined to be
4*52 per cent. The liquid still continued viscid. But when
acetic acid was added to it, the viscidity disappeared, the liquid
became transparent, and deposited white threads possessing the
following properties : 1. It had the colour, smell, taste, and elas-
ticity of gluten of wheat. 2. It was soluble in concentrated
acids, and alkaline hydrates. 3. It was soluble in cold water ;
the solution frothed. Alcohol and acids threw it down in flocks.
It amounted to 11*86 per cent., doubtless weighed while moist.
The liquid, after the separation of this substance, being con-
centrated, deposited crystals of acetate of soda, showing the ex-
istence of soda in synovia. The quantity of soda amounted to
0-71 per cent.
When strong sulphuric, muriatic, nitric, acetic, or sulphurous
acid was poured into synovia, white flocks precipitated, but they
were soon redissolved, and the viscidity of the liquid continued.
When very much diluted these acids precipitate the thready mat-
ter, and the viscidity of the synovia disappears.
Synovia, when kept in a dry atmosphere, gradually evaporat-
ed, leaving a scaly residue, in which cubic crystals and a white
saline efflorescence were apparent. The cubic crystals of com-
mon salt amounted to 1*75 per cent, of the synovia. The white
efflorescence was carbonate of soda.
* Ann. de Chim. xiv. 124.
4
SYNOVIA. 505
Synovia soon putrefied in a moist atmosphere, and during the
putrefaction ammonia was exhaled. When distilled per se, wa-
ter, ammonia, empyreumatic oil, and carbonate of ammonia came
over. The residue contained common salt, carbonate of soda,
and phosphate of lime.
According to Margueron, the synovia of the ox is composed of,
Fibrous matter, . 11-86
Albumen, . 4-52
Common salt, . 1*75
Soda, . . 0-71
Phosphate of lime, • O70
Water, . . 80-46
100-00
It is impossible not to be struck by the great resemblance of
the synovia examined by Margueron to the serum of blood. Is
it not possible that he may have obtained serum or lymph instead
of synovia ?
3. Dr John made some experiments on the synovia extracted
from the healthy joint of a horse.* It was light yellowish-red,
clear, of the specific gravity of 1-099, restored the blue colour to
reddened litmus-paper, and was coagulated by a boiling heat.
He found the constituents as follows :
Water, .... 92-8
Albumen, . . . .6*4
Animal matter not coagulable, with carbonate 1
of soda and common salt, . j
Phosphate of lime, . 0*15
Phosphate of soda, 1
Ammoniacal salt, J
99*95
He examined also the synovia from an ankylosed joint in con-
sequence of a wound. It was red, muddy from flocks of albumen,
thick and reddened litmus-paper. It coagulated when heated.
It contained insoluble albumen, soluble albumen, free phosphoric
acid, and the same salts as healthy synovia.
4. In 1817, M. Vauquelin examined the synovia of an ele-
phant that died in the Jardin du Roi at Paris. f
* Chem. Schr. vi. 146. f Jour, de Pharmacie, iii. 269.
506- LIQUID PARTS OF ANIMALS.
It had a slight colour/ doubtless, from an admixture of a little
blood. Its consistence is thready, like that of a decoction of lint-
seed, feel soft, taste slight, but saline. On standing a few hours
it deposits white filaments, "apparently of fibrin, (6 ounces depo-
sited only 1 grain.) But it amounted to only yjV&tf1 of the sy-
novia. He found its constituents similar to those of the synovia
of the ox. Vauquelin conceives, that, besides albumen, it con-
tains a peculiar substance, neither coagulable by heat nor acids,
but capable of being precipitated by tannin. He found also so-
da, chloride of sodium, and chloride of potassium, but could not
discover any alkaline phosphates,
5. Mr Brande, in the year 1809, made some experiments on
the synovia of the shark (Squalus maximus.}* In these fish
there exist in the vertebrae a peculiar synovia, which fills the ca-
vities between each. Mr Brande found this synovia of the speci-
fic gravity 1'027. It had the smell of fish oil. It did not mix
with water till the action was assisted by heat. The solution was
neither precipitated by boiling, nor by alcohol, nor by tannin.
It contains in solution a substance approaching to mucus by its
properties ; but which, in certain circumstances, is transformed
into a modification of gelatin and albumen. It is probably a
substance sui generis.
Such is the imperfect collection of chemical facts hitherto as-
certained respecting synovia. We do not know as yet whether
it contains any peculiar animal principle, though such an opi-
nion is at least probable.
CHAPTER XV.
OF MUCUS.
THE word mucus in the Latin language signifies properly the
gelatinous looking matter secreted in the nose, to defend it from
the action of the air that passes through it, and vulgarly called
snot. But in chemistry, it is used to denote the slimy transpa-
rent matter, which lines all the cavities of the body through which
foreign matters pass, in order to protect the internal surface of
* Phil. Trans. 1809, p. 184.
MUCUS. 507
these cavities from the action of those foreign matters. It is dis-
tinguished by the name of the cavity in which it is secreted.
Thus we have the mucus of the mouth, of the nose, of the trachea;
of the stomach and intestines, of the gall-bladder, and of the uri-
nary organs.
By mucus is meant in chemistry a solid body, which does not
dissolve in water ;'lbut which absorbs that liquid, swells up, be-
comes soft, viscid, and even half-fluid in some cases. It is se-
creted by small glands^ scattered over the mucous membranes,
which throw it out, and spread it equably over the whole surface
of the mucous membrane. It is soaked with water, holding
in solution^the same salts which exist in the serum of the
blood.
Its characters vary somewhat in different mucous membranes,
doubtless according to the nature of the foreign substances from
which it is intended to protect the membrane on which it is spread.
On this^account it will be requisite to give the chemical proper-
ties of the different species of mucus so far as they have been
determined.
1. Mucus of the mouth. — This mucus subsides from saliva
left at rest in small white flocks. In sulphuric, muriatic, and
acetic acids, it becomes transparent and horny. But it does not
dissolve in these acids, nor give out any phosphate of lime to
them ; though when incinerated it always leaves traces of that
salt.*
2. Mucus of the nose. — This mucus, when secreted from a
healthy membrane, is white or colourless, translucent, loaded
with water, so as to assume much of the appearance of that por-
tion of gum-tragacanth which is insoluble in cold water after it
has imbibed as much as it can of that liquid. In the first stage
of a catarrh, it is secreted in greater abundance than usual,
and is at first transparent and almost altogether liquid ; but
as the disease advances the mucus acquires more and more
consistency, becomes white and opaque, and finally yellow
and nearly solid. Healthy mucus of the nose, according to the
analysis of Berzelius, is composed of the following constitu-
ents:
* Berzelius.
508 LIQUID PARTS OF ANIMALS.
Water, . . . 933.7
Mucus, . . . 53-3
Chlorides of potassium and sodium, . 5-6
Lactate of soda with animal matter, . 3-0
Soda, . 0-9
Albumen and animal matter soluble in water, but in- |
soluble in alcohol, with trace of phosphate of soda, /
1000-0*
When the mucus of the nose is immersed in water, it imbibes
so much as to become transparent and almost invisible ; and
when dried on blotting-paper, loses nearly all the moisture
which it had imbibed. This may be repeated as often as we
please; but the mucus gradually assumes a yellow colour.
Though boiled in water it does not lose its mucilaginous nature.
It dissolves in dilute sulphuric acid. Nitric acid at first coa-
gulates it ; but if the digestion be continued the mucus is at last
dissolved into a clear yellow liquid. Acetic acid hardens, and
does not dissolve it even at a boiling heat. Caustic alkali ren-
ders it at first more viscid ; but at last dissolves it into a clear
liquid. Tannin coagulates it.
3. Mucus of the bronchise in a state of health, when expecto-
rated, is pretty similar to the mucus of the nose, only its consist-
ence is greater and its colour bluish. It possesses, so far as I
have tried them, the same characters as the mucus of the nose.
The blue colouring matter is probably derived from matter sus-
pended in the air drawn into the lungs. It has been remarked
to be darker in those who live in great towns than in those who
live in the country.
Dr Pearson made numerous experiments on the matter ex-
pectorated from the lungs, which were published in the Philo-
sophical Transactions for 1809. He distinguished seven differ-
ent kinds of it. 1 . The jelly-like transparent kind of a bluish
hue expectorated in health. This is the true mucus of the bron-
chiae. 2. The thin mucilage-like transparent matter so copi-
ously expectorated in bronchial catarrh. 3. The thick opaque
straw-coloured, or white and very tenacious matter coughed up
in a great variety of bronchial and pulmonary affections. 4.
Puriform matter secreted without any breach of surface of the
* Annals of Philosophy, ii. 382.
MUCUS. 509
bronchial membranes in pulmonary consumption. 5. Mixtures
of the second, third, and fourth kinds of matter. 6. Pus from
vomicae of tubercles. 7. Pus from vomicse of simple inflamma-
tion of the lungs without tubercles.
He made no attempt to ascertain the properties of the mucus
contained in these'expectorated matters, but determined the saline
contents, and found them to be, 1. Common salt, in the proportion
of from 0-15 to 0-25 per cent. ; 2. Phosphate of lime, about
0-05 per cent. ; 3. Ammonia united probably with phosphoric
acid ; 4. Phosphate of magnesia ? 5. A sulphate ; 6. Carbonate
of lime ; 7. Silica ? 8. Oxide of iron.
Dr Golding Bird has made some interesting experiments on
the mucus secreted so abundantly during the first stage of acute
bronchitis. When freed from air bubbles it is a transparent co-
lourless liquid, rendered reddish brown by sulphuric acid, but
the colour disappears on adding water. Nitric acid at first co-
agulates it, but dissolves it when heated. Muriatic acid gives it
a lilac tint. Ammonia, by the assistance of heat, produces a
gelatinous solution, becoming turbid when diluted with water.
Acetic acid produces a partial coagulation. Infusion of nut-
galls causes a copious precipitate. When evaporated to dryness
it leaves a gum-like residue, leaving, when incinerated, a white
alkaline carbonate.
When exposed for a few days to the air it lets fall a cream-co-
loured deposit, possessing the characters of coagulated albumen.*
Dr Babington has shown that the bronchial mucus is always
alkaline, f
4. Mucus of stomach and intestines. — In these organs the mu-
cus covers the whole internal surface. When an animal is kil-
led after a long fast we may scrape a great deal of mucus from
the mucous membrane, and obtain it pure by washing it in dis-
tilled water. It is a white translucent gelatinous-looking substance,
without taste or smell. When dried it loses the property of be-
coriiing mucilaginous when water is poured over it ; but if we
add a little alkali to the water the gelatinous state is instantly
restored. From this we see the use of the small quantity of soda
which this mucus always contains in its natural state.
Acids coagulate it, even acetic acid, and often make it assume
the form of a kind of cake. Acids do not dissolve it even at a
* Phil. Mag., (3d series) xiii. 15. f Guy's Hospital Reports, ii. 539.
510 LIQUID PARTS OF ANIMALS.
boiling temperature ; though they dissolve something. If we
decant off the acid, and then treat the mucus with water, an ad-
ditional portion is dissolved, these solutions are precipitated by
the infusion of nut-galls, but very seldom by prussiate of potash.
Very dilute caustic potash or soda readily dissolves the mucus of
the intestines. From this solution it is thrown down in great
part by the acids. It is dissolved also by very dilute ammonia,
and equally precipitated by acids.
5. Mucus of gall-bladder. — This mucus in its natural state is
more transparent than that of the nose, but has a yellow colour
ob\iously from a mixture of bile. When dried it loses the pro-
perty of becoming gelatinous from imbibing water, all the acids
coagulate it into a yellow mass, which reddens litmus. Alkalies
make it again viscid. Alcohol coagulates it into a horny mass,
which cannot again be rendered gelatinous. If we neutralize by
an acid the solution of this mucus in potash ley, we obtain a mud-
dy thready solution.
According to Fromherz and Gugert, the solution of the mu-
cus of the human gall-bladder in potash ley is not precipitated
by muriatic acid, unless we add at the same time a portion of tinc-
ture of nut-galls.*
Tiedemann and Gmelin made several experiments upon the
mucus from the gall-bladder of oxen. It was soft and greenish
in its natural state, but when dried, it became hard, brittle, and
deep grayish-green. It swelled when heated, and burnt with
flame, and giving out the smell of burning horn. The ashes con-
stituted 8 per cent, of the dried mucus. They consisted chiefly
of phosphate of lime with a little carbonate, and contained traces
of an alkaline sulphate and chloride. This mucus was partially
dissolved by dilute sulphuric and muriatic acid, and the solution
was slightly precipitated by tincture of nut-galls, but nitric acid
did not seem to dissolve any of it. What remained insoluble in
the acids being digested in hot water, was partially dissolved and
the solution was precipitated by tincture of nut-galls. It soften-
ed and partly dissolved in ammonia.f
6. Mucus of urinary bladder and urethra. — When fresh, it
is white and translucent When dried, it assumes a rose-red
colour, and is but little softened by water. It is not altered by
acids ; ammonia sometimes increases its viscosity, sometimes not.
" Schweigger's Jour. 1. 70. f Recherches sur la Digestion, i. 43.
TEARS. 511
When heated over a spirit lamp it dries, swells a little, and is char-
red, and burning with a small flame. When digested in ether,
a little fatty matter is dissolved, to which the flame was doubt-
less owing. When examined by the microscope, it appears com-
posed of irregular transparent plates, mostly colourless, though
sometimes yellowish. When globules appear in it the mucus is
probably partially converted into pus. The diameter of these
globules varies from I?^th to T^¥5th of an inch.
CHAPTER XVI.
OF TEARS.
THE fluid which is employed in lubricating the eye, and which
is emitted in considerable quantity, when we express grief by
weeping, is known by the name of tears. It is secreted by the
lachrymal gland, a conglomerate gland about three-quarters of
an inch in length, and half an inch in breadth, situated in the
upper and outer part of the orbit. No attempt has been made
to make a chemical examination of the tears, since the experi-
ments of Fourcroy and Vauquelin in 1791.*
The liquid, called tears, is transparent and colourless like
water. It has no perceptible smell, but its taste is sensibly sa-
line. Its specific gravity has not been determined, though it is
known to be heavier than distilled water. It tinges syrup of
violets green, and of course contains a free alkali. It may be
mixed with water in all proportions. Alkalies unite with it rea-
dily, and render it more fluid. The mineral acids do not sensi-
bly alter it. When exposed to the air, it gradually evaporates
and becomes thicker. About the end of the evaporation a num-
ber of cubic crystals of common salt make their appearance.
They give a green tinge to vegetable blues, and therefore con-
tain; an excess of alkali. The mucous animal matter of tears ac-
quires a yellow colour as it dries. Tears boil like water, except-
ing that a considerable froth collects on the surface. When boil-
ed to dryness over the steam-bath, tears lose 96 per cent, of
their weight, which flies off in the state of water. The remain-
ing 4 parts have a yellowish colour. When strongly heated,
* Jour, de Phys. xxxix. 254.
LIQUID PARTS OF ANIMALS.
water and a little empyreumatic oil is driven off. The residue
consists of common salt mixed with some soda and small quanti-
ties of the phosphates.
Alcohol precipitates white flocks from tears. These flocks were
considered by Fourcroy and Vauquelin as constituting a species
of mucus. This mucus, they say, has the property of absorbing
oxygen from the atmosphere, and of becoming thick and viscid,
and of a yellow colour. It is then insoluble in water, and re-
mains long suspended in it without alteration. When chlorine
is added to tears, a yellow flocky precipitate falls, possessing the
same properties as inspissated mucus. This property of the mu-
cus of tears enables us to understand the alterations which that
liquid undergoes when long exposed to the action of the atmo-
sphere, as is the case with those persons who labour under ajis-
tula lachrymalis.
The substances found in tears by Fourcroy and Vauquelin
are the following :
Water. Soda.
Mucus. Phosphate of lime.
Common salt. Phosphate of soda.
CHAPTER XVII.
OF THE LIQUORS OF THE EYE.
THE globe of the eye consists of several coats inclosing with-
in them three different humours. The one farthest back, and
constituting a considerable portion of the eye-ball, is called the
vitreous humour. It is a transparent and colourless liquid inclos-
ed in a great number of cells. Between the cornea and the lens
of the eye, there is another colourless and transparent liquid cal-
led the aqueous humour; and the crystalline lens, though not li-
quid but solid, has got the improper name of the crystalline hu-
mour of the eyes.
The first attempt to examine these three humours, and to deter-
mine their chemical constitution, was made by Mr Chenevix in
1802.* He made his experiments on the eyes of sheep and oxen,
and made some observations also on the humours of the human
* Phil. Trans. 1803, p. 195.
LIQUORS OF THE EYE. 513
eye. Soon after, Mr Nicolas made a set of experiments on the
eyes of sheep and oxen, and announced the presence of phos-
phate of lime in all the humours, though Chenevix had not been
able to detect any.* In 1808, Berzelius published the second
volume of his Animal Chemistry, in which he gave an account
of a set of experiments which he had made to determine the che-
mical constitution of these humours.f The same experiments were
republished in the General Views of the Composition of Animal
Substances, published in English in 18134 He was equally un-
successful with Chenevix in his attempts to detect the presence
of phosphate of lime in these humours.
I. Eye of the sheep.
1. The aqueous humour of the eye of the sheep is a clear and
transparent liquid like water, having (while fresh) very little
taste or smell. Its specific gravity at 60° is 1-0090, as determined
by Chenevix. Nicolas rates it as low as 1-C009.
It scarcely alters vegetable blues while fresh, but when kept,
ammonia is generated, which gives it an alkaline reaction.
When heated to the boiling temperature, a very slight coagulum
appears. Chenevix says that when evaporated to dryness, it
leaves a residuum weighing not more than eight per cent of the
original liquid. But there must be a mistake in the statement,
as no other experimenter has obtained a residue weighing so much
as 2 per cent. Tincture of nut-galls occasions a precipitate both
before and after it has been boiled. From this Chenevix infers
that the aqueous humour contains gelatin. But it is more pro-
bable that the precipitate by tannin after boiling proceeds from
a residue of albumen which had not been thrown down by boil-
ing. Nitrate of silver detects in this liquor the presence of chlo-
rine. Acetate of lead throws down a white matter, but no pre-
cipitate is produced by any other metallic salt.
The constituents of the aqueous humour of the sheep's eye, ac-
cording to Berzelius, are
Water, . . . 98-10
Albumen, . . . trace.
Chlorides and lactates, . . 1«15
Soda with animal matter soluble only in water, 0-75
100-
* Ann. de Chim. liii. 307. f Djurkemie, ii. 206.
$ Annals of Philosophy, ii. 385.
K k
LIQUID PARTS OF ANIMALS.
2. The vitreous humour possesses the same properties as the
aqueous. Its specific gravity, as determined by Chenevix, is the
same as that of the aqueous humour. Its constituents, accord-
ing to the analysis of Berzelius, are
Water, . . . 98-40
Albumen, . . . 0-16
Chlorides and lactates, . . 1-42
Soda, with animal matter soluble only in water, 0-02
100-00
3. The crystalline lens is solid and transparent, it is com-
posed of a congeries of very fine coats. Its specific gravity is
1-1000. But it is densest and most solid in the centre, and the
specific gravity and consistency gradually diminish as we ap-
proach the circumference. Chenevix found the weight of a fresh
crystalline lens of an ox to be 30 grains, and its specific gra-
vity was 1-0765. On paring away the external portion, and leav-
ing only a central nucleus weighing 6 grains, the specific gravity
of this nucleus was 1-1940.
It dissolves almost entirely in water. The solution is partly
coagulated by heat and gives a copious precipitate with tannin,
both before this coagulation and after it. Berzelius conceives
that this property is owing to the presence of a peculiar matter
possessing all the characters of the colouring matter of the blood,
except the red colour. But what was considered as the colour-
ing matter of blood when Berzelius made his experiments, was
chiefly albumen, but containing a very little fibrin and hemato-
sin. Hence it is probable that this peculiar matter is chiefly al-
bumen. The constituents of the lens were found by him to be,
Water, . 58-
Peculiar matter, . • . .35-9
Chlorides, lactates, animal matter soluble in alcohol, 2-4
Animal matter soluble only in water, with phosphates, 1 -3
Insoluble cellular membrane, . . 2*4
100-0
The peculiar matter of the lens when burnt leaves a little ash
containing a very small portion of iron. When its solution in
water is coagulated by boiling, the liquid in which the coagulum
was formed reddens litmus, has the smell of the humours of the
muscles, and like them, contains free lactic acid.
LIQUORS OF THE EYE. 515
II. The humours of the human eye are composed of the same
ingredients as those of the sheep ; though they differ somewhat
in their specific gravity. The specific gravity of the aqueous and
vitreous humours is 1 -0053, and that of the crystalline lens 1 -07 90
as determined by Chenevix.
III. The humours of the eyes of oxen resemble those of the
sheep in their composition. The specific gravity of the aqueous
and vitreous humours is 1*0088, and that of the lens 1*0765, as
determined by Chenevix.
From the specific gravities of the aqueous and vitreous hu-
mours compared with that of the lens in different animals, Che-
nevix has concluded that the difference between the density of
the aqueous and vitreous humours and of the lens, is in the in-
verse ratio of the diameter of the eye, taken from the cornea to
the optic nerve.
IV. Chenevix examined also the humours of the eyes of birds.
He found them composed of the same materials as the eyes of
sheep. But in birds the specific gravity of the vitreous humour
was greater than that of the crystalline. *
V. Lassaigne examined the vitreous humour of a blind horse.
Its specific gravity was 1*059, while that of the vitreous humour
from a healthy eye was only 1*0008. The vitreous humour in
the blind horse was very thick, yellowish, red and muddy, from
coagulated albumen floating in it. The albumen in solution
amounted to about eight per cent. It was yellow, soluble in alco-
hol, and resembled the brown colouring matter of bile, and the
salts (similar to those in blood) were more abundant than in
the healthy vitreous humour, f
In the year 1821, Dr Rudolph Brandes made a chemical ana-
lysis of the crystalline lens of a horse,J and obtained the follow-
ing constituents :
Water, ... 75
Albumen soluble in cold water, . 7
Albumen insoluble in cold water and ap- 1 , ^
preaching fibrin in its nature /
Sulphate, muriate, lactate of potash and ^
soda, with a substance precipitated by >- 1
tincture of nut-galls, • )
95
* Journal of the Royal Institution, i. 297. f Jour* Chim. Med. iv. 476.
\ Schweigger's Jour, xxxi. 194.
516 LIQUID PARTS OF ANIMALS.
Brought over, . . 95
Ehosphate of lime, . . trace.
95
Loss, . 5
100
VI. A curious set of experiments has been made by Leopold
Gmelin on the black pigment, which lines the choroid coat of
the eye. From 500 eyes of oxen and calves he collected 75
grains of this substance. Its colour is blackish brown. It is
tasteless, and adheres to the tongue like clay. It is insoluble in
water, alcohol, ether, oils, lime-water, and distilled vinegar. It
dissolves in potash and ammonia when assisted by heat, and is
again precipitated by acids. Sulphuric acid dissolves it and ac-
quires a black colour. Muriatic acid forms only an imperfect
solution. Nitric acid dissolves it, and changes its colour to red-
dish-brown. When distilled it yields water, a brown oil, and
carbonate of ammonia. It gives out at the same time carburetted
hydrogen, carbonic oxide, azotic and oxygen gas. The coal re-
maining in the retort consists almost entirely of charcoal. *
CHAPTER XVIII.
OF CERUMEN.
CERUMEN* or ear-wax is a yellow-coloured liquid, secreted by
the glands of the auditory canal, which gradually becomes con-
crete by exposure to the air. It is intended to lubricate the ca-
nal, to keep the parts soft, and to prevent insects from making
their way to the tympanum. This secretion was first subjected
to a chemical examination by Fourcroy and Vauquelin, who
was supplied with a sufficient quantity of serum for the purpose
by M. Halle. Fourcroy has stated the result of this examina-
tion in his Systems des Connoissances Chimiques.\ In the second
volume of Berzelius's Animal Chemistry, published in 1808, he
* Schweigger's Jour. x. 507.
•f From x»goc, wax, from its resemblance to wax.
£ Vol. ix. p. 454 of the English translation.
CERUMEN. 517
merely gives the result of Vauquelin's analysis, without adding
any additional facts of his own.* Nor does he take any notice
of cerumen in his General Views of the Composition of Animal
Fluids, published in 1813.f But in the seventh volume of his
Traite de Chimie, published in 1833, he gives the result of a set
of experiments which he had made on that secretion. To these
chemists, so far as my knowledge extends, we are indebted for all
the chemical knowledge of cerumen which we at present possess.
When collected, it has an orange-yellow colour, and a bitter
taste, and has a consistency nearly equal to that of soft wax.
When slightly heated on paper it melts and stains the paper like
a fixed oil ; at the same time it emits a slightly aromatic odour.
On burning coals it softens, gives out a white smoke similar to
that emitted by burning fat. It afterwards melts, swells, be-
comes dark-coloured, and emits an ammoniacal and empyreuma-
tic odour. A light coal remains behind. When cerumen is
agitated in water, it forms a kind of emulsion, which soon pu-
trefies, depositing at the same time white flocks,
According to Vauquelin it is composed of,
Brown oil, . 62-5
Albumen, . 3 7 '5
100-0
The oil is butyracious and soluble in alcohol. The albumen
contains a bitter extractive matter, the proportion of which was
not ascertained.
Berzelius found that when cerumen was treated with ether it
swelled up a little, and the ether extracted a fatty matter, which
scarcely communicated any colour to it. When we mix the
ether with water and distil, the fatty matter remains on the sur-
face of the water without being in the least soluble in that liquid.
This fatty matter has the consistence of duck's grease. It does
not redden litmus, melts easily into a transparent yellowish oil ;
but resumes its white colour on cooling and concreting. This
fatty matter contains stearin and olein separable from each other
by alcoh6l. It is easily converted into a soap, which has a smell
analogous to sweat. When the soap is decomposed by muriatic
acid, the oily acids separate in a white powder, which melts at
about 104°.
* Djurkemien, ii. 228. t Annals of Philosophy, ii. 19.
518 LIQUID PARTS OF ANIMALS.
The cerumen thus deprived of its fat by ether gives a brown-
ish yellow colour to alcohol. When the alcohol is evaporated
it leaves a brownish-yellow extractive matter, which is soluble in
water. When the aqueous solution is evaporated to dryness, it
leaves the matter under the form of a deep-yellow, transparent,
brilliant varnish. It has no smell, but an extremely bitter taste.
When exposed to the air it softens and becomes viscid like tur-
pentine. When burnt it gives out an animal odour, and leaves
an ash composed of carbonate of potash and carbonate of lime.
Its solution in water is yellow, and is not precipitated by nitrate
of silver, showing that it contains no chloride. Oxalate of am-
monia throws down lime. Nitrate of lead precipitates the bitter
tasted substance, and discolours the liquid. It is also precipitated
completely by the protochloride of tin ; but not by corrosive
sublimate, and very imperfectly by the tincture of nut-galls. It
is obviously a peculiar animal principle, which ought to be distin-
guished by a peculiar name. The term otin might perhaps an-
swer the purpose.
When the portion of cerumen insoluble in ether and alcohol
is digested in water, that liquid dissolves a small quantity of a
pale-yellow matter, which may be obtained by evaporating the
water. It has a sharp taste, and is neither precipitated by lime-
water nor by diacetate of lead, corrosive sublimate, nor infusion
of nut-galls.
The residue of the cerumen insoluble in ether, alcohol, and
water constitutes a great proportion of it. When this residue
is digested in acetic acid, it swells up and becomes gela-
latinous ; but when we dilute the mixture with water, the acid,
even after several weeks' digestion, dissolves but a portion of the
whole. The solution is yellowish, and when evaporated to dry-
ness, leaves a mass insoluble in water, but soluble in dilute ace-
tic acid, from which it is precipitated by prussiate of potash,
showing that it contains albumen. The prussiate of potash does
not precipitate the whole. For the liquid is still precipitable by
the infusion of nut-galls.
The portion of cerumen insoluble in acetic a,cid is much more
considerable than that which dissolves. Jt is a brownish, muci-
laginous, translucent mass, which falls rapidly to the bottom of
the liquid. When digested in caustic potash at the temperature
of about 100°, very little of it dissolves. The solution is yellow-
PERSPIRATION AND SWEAT. 519
ish. It is not precipitated when supersaturated with acetic acid,
and prussiate of potash does not throw down any thing from the
acid liquor, but the infusion of nut-galls throws down a copious
precipitate.
The portion insoluble in potash when burnt exhales the smell
of burning animal matter, and leaves a very little alkaline ash.
Boiled in a very concentrated solution of caustic potash, it gives
the liquor a brownish-yellow colour, and emits the smell of horn
subjected to the same treatment. A little matter falls, which is
a compound of the dissolved substance and potash. It is soluble
in water. Thus, the substance in cerumen, which resists the ac-
tion of all the reagents except very concentrated caustic potash,
possessed many of the properties of horn, though it differs from
that substance in several of its characters.
From these experiments of Berzelius, it appears, that cerumen
is composed of,
Stearin. Yellow matter soluble in water.
Elain. Albumen (uncoagulated).
Otin. Albumen (coagulated).
Lactates of lime and potash or soda.
CHAPTER XIX.
OF PERSPIRATION AND SWEAT.
THAT a quantity of matter is constantly emitted from the skin
has been long known, as this matter in most cases is dissipat-
ed as fast as it is thrown out of the body, and of course without
being perceived, unless peculiar contrivances be used to detect it ;
it has got the name of insensible perspiration,
Many experiments have been made to determine the quantity
of matter perspired through the skin. For the first set and not
the least remarkable, we are indebted to Sanctorius, who con-
tinued them for no less than thirty years. According to him,
the average quantity of matter perspired through the skin in a
natural day amounts to not less than 50 ounces.* A similar
set of experiments was afterwards made in France by Dodart,
and in England by Keil. According to Dodart the perspira-
* See Quincy's Medicina statica, p. 54.
520 LIQUID PARTS OF ANIMALS.
tion amounts to 24 ounces in twenty-four hours. According to Keil
it is rather more than 31 ounces, or very nearly 2 Ibs avoirdupois.*
Dr Bryan Robertson and Mr Rye made a similar set of experi-
ments in Ireland, as did Dr Lining in Carolina. But these expe-
rimenters neglected to distinguish the matter perspired through
the skin from what was thrown out by the lungs.
Lavoisier and Seguin were the first persons who attempted to
ascertain the amount of the matter perspired by the skin, and to
separate it from what was thrown out by the lungs. A bag com-
posed of varnished silk, and air-tight, was procured, within which
Seguin, who was usually the subject of experiment, was enclos-
ed ; every part of the body being included. There was a slit
in the bag opposite to the mouth, and the edges of the slit were
accurately cemented round the mouth by means of a mixture of
turpentine and pitch. Thus everything emitted from the body
was retained in the bag, except what made its escape from the
lungs during expiration. By weighing himself in a sensible ba-
lance before the experiment began, and again after he had been
for some time enclosed in the bag, the difference of weight
gave the matter exhaled from the lungs. While the weight of
the bag before and after the experiment gave data for deter-
mining the quantity of matter exhaled from the skin during the
same length of time. The following facts were ascertained by
these experiments :
1. The maximum of matter perspired in a minute amounted
to 26-25 grains troy ; the minimum to 9 grains ; which gave
17-63 grains at a medium in the minute, or 52'89 ounces in
twenty-four hours. This is very near the quantity stated by
Sanctorius as the result of his numerous experiments.
2. The quantity perspired is increased by drink ; but not by
solid food.
3. Perspiration is at its minimum immediately after a repast.
It reaches its maximum during digestion. f
Mr William Cruikshanks published a work on insensible per-
spiration in 1795. He seems to have been the first person who
thought of collecting the matter perspired so as to be able to
judge of its nature. He inclosed his hand within a glass vessel
and luted its mouth to his wrist by means of a bladder. The
interior surface of the glass became gradually dim, and drops of
* See Quincy's Medic ina statica, p. 323.
t Fourcroy, ix. 276, English translation.
PERSPIRATION AND SWEAT.
water trickled down. By keeping his hand thus enclosed for an
hour, he collected 30 grains of a liquid which possessed the
properties of water. On repeating the same experiment at nine
in the evening (thermometer 62°), he collected only 12 grains.
The mean of these two trials is 21 grains.* But as the hand is
more exposed than the trunk of the body, it is reasonable
to believe that the perspiration from the trunk is greater than
from the hand. Let us therefore take 30 grains per hour as the
mean, and let us suppose with Cruikshanks, that the hand is one-
sixtieth of the surface of the body. The total perspiration in twenty-
four hours would amount to 43,200 grains, or 90 ounces troy.
This being much more than the quantity stated by Lavoisier and
Seguin, or even than the amount ascertained by Sanctorius, we
must conclude that more matter is perspired from the hand than
the trunk, provided Cruikshanks' estimate of the ratio between
the surface of the hand and the body be not erroneous.
He repeated the experiment again after hard exercise, and col-
lected in an hour 48 grains of water. He found that this aque-
ous vapour pervaded his stocking with ease, and that it made its
way through a shamoy leather glove, and even through a leather
boot, though in much smaller quantity than when the leg want-
ed that covering.f
It is evident from these experiments of Cruikshanks just stat-
ed, that the matter perspired consists chiefly of water. But it
follows also, from his experiments, that carbonic acid gas is
evolved from the skin. The air of a glass vessel in which his
hand and foot had been confined for an hour contained carbo-
nic acid gas ; for a candle burnt dimly in it, and it rendered
lime-water turbid.J M. Jurine found that air which had remain-
ed for some time in contact with the skin consisted in a great
measure of carbonic acid gas.§ The same conclusion follows
from the experiments of Ingenhousz and Milly.|| Trousset ob-
served that gas was separated copiously from the skin of a pa-
tient of his while bathing.1I
Besides water and carbonic acid, the skin emits also an
odorous substance. That every animal has a peculiar smell is
well known. The dog can discover his master, and even trace
* On Insensible Perspiration, p. 68. f H>id. ?• 82.
\ On Insensible Perspiration pp. 70 and 81. § Encyc. Meth. Med. i. 515.
U Encyc. Meth. Med. p. 511. ^ Ann. de Cbim. xlv. 73.
LIQUID PARTS OF ANIMALS.
him to a distance by the scent. A dog chained for some hours
after his master had set out on a journey of some hundred miles,
followed his footsteps by the smell, and found him on the third
day in the midst of a crowd.* Mr Cruikshanks, to discover the
nature of this substance, wore for a month the same vest of fleecy
hosiery during the hottest part of the summer. He found an
oily-looking substance accumulated in considerable masses on
the nap of the inner surface of the vest, in the form of black
tears. When rubbed on paper it rendered it transparent, and
gave it a greasy stain. It burnt with flame, leaving a charcoal
behind it.f
Thenard repeated this experiment of Cruikshanks in 18064
A flannel jacket, previously well washed in distilled water and
dried, was worn for ten days next the skin below a linen shirt.
It was then washed in pure water, and the aqueous liquor was
distilled in a retort. The liquid that came over had the smell of
sweat, and contained a small quantity of acetic acid. The liquid
remaining in the retort, when sufficiently concentrated, assumed
the appearance of an acid syrup, which contained common salt ;
but no salt of lime. It was sparingly precipitated by infusion of
nut-galls. Thenard concluded, from his experiments, that the
matter of perspiration, besides water, common salt, and acetic
acid, contains a little phosphate of soda, traces of phosphate of
lime and of iron, and an animal substance precipitated by infu-
sion of nut-galls ; probably albumen.
The most recent experiments on the matter of perspiration have
been made by Anselmino.§ He plunged his arm into a glass
jar, and luted the mouth of it to the arm below the shoulder.
The matter perspired condensed on the inside of the glass as in
Cruikshanks's experiment, and in six hours he collected a table-
spoonful of it. He divided the liquor thus obtained into three
portions, and subjected them to the following trials :
1. One portion was mixed with a drop of sulphuric acid and
then evaporated to dryness, This residue was mixed with a little
caustic potash, and a glass rod dipped in muriatic acid was held
over it. Evident fumes of sal-ammoniac made their appearance ;
showing that ammonia existed as one of the constituents of mat-
ter of perspiration.
* Cruikshanks on Insensible Perspiration, p. 93. f Ibid. p. 92.
t Ann. de Cbim. lix. 262. § Berzelius, Traite de Chimie, vii. 328.
PERSPIRATION AND SWEAT. 523
2. A second portion was digested over oxide of lead, and the
digestion continued in an open vessel till all the liquid had been
driven off. The dry residue being moistened with sulphuric acid,
fumes of acetic acid were given out recognizable by the smell.
3. Lime-water was added drop by drop to the third portion-
It became muddy, and carbonate of lime was deposited. From
these experiments Anselmino concluded that the matter of per-
spiration contains acetate of ammonia and carbonic acid.
Collard de Martigny assures us that the skin not only gives
out carbonic acid gas, but also hydrogen gas and azotic gas,
though in very minute quantity.* But how far these statements
are correct we do not at present know.
When the temperature of the body is increased either by ex-
posure to a hot atmosphere or by violent exercise, the matter of
perspiration not only increases in quantity, but even appears in
a liquid form. This is known by the name of sweat. This sweat
serves a very important purpose. No sooner is it thrown on the
surface of the skin than it begins to evaporate, absorbs heat, and
thus the temperature of the body is prevented from rising. This
is the reason that animals can endure a much higher tempera-
ture without injury than could have been supposed. The expe-
riments of Tillet, and the still more decisive experiments of For-
dyce and his associates, are well known. These gentlemen re-
mained for a considerable time in a room, the atmosphere of
which was hotter than boiling water.
Sweat is a transparent and colourless liquid, having a saline
taste, and yielding, when evaporated, crystals of common salt.
According to Berzelius, it contains the same salts as those which
exist in the acid liquor obtained from animal muscle by expres-
sion ; namely, lactates of potash, soda, lime, and magnesia, to-
gether with common salt, sal-ammoniac, and traces of chloride
of potassium. It contains also traces of phosphate of soda and
phosphate of lime. It contains also a small quantity of animal
matter insoluble in alcohol.
Anselmino examined a quantity of sweat collected by sponges
from the body of a man made to sweat abundantly in a hot stove.
The liquid thus obtained was muddy, probably from small por-
tions of the epidermis detached by the friction. It had a pecu-
liar smell, varying in intensity in different individuals. A por-
* Berzelius, Traite de Chimie, vii. 325.
LIQUID PARTS OF ANIMALS.
tion of it was filtered and distilled over the steam-bath. The
liquid that passed into the receiver contained acetate of ammonia.
When the liquor of sweat was evaporated to dryness it left
from a half to one and a-quarter per cent, of dry residue. This
residue being treated with alcohol of 0-833, a portion remained
undissolved. When the alcoholic solution was evaporated to dry-
ness there remained an extractive matter mixed with a great
number of saline crystals. From this matter absolute alcohol
separated an acid extractive substance, containing, according to
Anselmino, acetic acid, acetate of potash, and an animal matter
precipitable by infusion of nut-galls. The portion of matter in-
soluble in absolute alcohol consisted of common salt with a little
chloride of potassium, and an animal substance not precipitable
by chlorine, chloride of tin, nor corrosive sublimate.
The portion of dried sweat left by alcohol is almost all solu-
ble in warm water, a little deep-gray powder only remaining.
It seems to be a mixture of epidermis and phosphate of lime.
When burnt it leaves a bulky ash, consisting of phosphate of
lime, mixed with a small quantity of carbonate of lime. The
portion dissolved in the warm water contains sulphates, and an
animal matter precipitated by chloride of tin, and by infusion of
nut-galls. Chlorine occasions no immediate precipitate ; but in
twenty-four hours white flocks separate from the liquid.
According to the analysis of Anselmino 100 parts of the dry
residue from sweat are composed as follows : —
Matters insoluble in water and alcohol, 1
(mostly salts of lime,) . J
Animal matter soluble in water, and not 1
in alcohol, with sulphates, /
Matters soluble in weak alcohol, com- 1
mon salt, and animal extract, /
Matters soluble in absolute alcohol, ani-
mal extract, lactic acid and lactates,
100
Anselmino found, likewise, that 100 parts of the dry residue of
sweat when burnt leave 22'9 of ashes, containing carbonate,
sulphate, and phosphate of soda ; a little of the same acids com-
bined with potash and common salt, all soluble in water. Be-
PERSPIRATION AND SWEAT. 505
sides phosphate and carbonate of lime, and a trace of peroxide of
iron, which are insoluble in water. *
Anselmino found that the sweat, during a fit of the gout, con-
tained more ammonia and saline matter than when in a state of
health. He found, also, that a critical sweat, during a rheuma-
tic fever, contained a good deal of albumen.
If any conclusion can be deduced from the smell, sweat in
different parts of the body is not identical. That of the feet
has quite a different smell from that of the arm-pits ; while that
of the groin in fat persons has often the smell of butyric acid.
Little is known respecting the perspiration and sweat of the
inferior animals. It is well known that the genera of quadrupeds
belonging to the dog and the cat tribe do not perspire at all. In
ruminating animals and pachydermata, on the contrary, perspira-
tion is abundant. Anselmino has examined the crusts of dried
sweat, which may be separated from the skin of a horse by the
brush. Being digested in hot water a pulverulent matter re-
mained undissolved. The solution was evaporated to dryness,
and the residue digested in alcohol of O833. The solution ob-
tained gave, when evaporated, a brown extract filled with saline
crystals. Absolute alcohol dissolved from it an acid extractive
matter holding in solution a combustible salt of potash. Hence
it seems to be of the same nature with the matter obtained from
human sweat by a similar process. The absolute alcohol left
common salt mixed with an extractive matter, having a strong
odour of a horse.
The portion of the residue left undissolved by the alcohol of
0-833 dissolved in water, to which it communicated a brown co-
lour. Besides common salt and sulphate of soda, it contained
an animal matter, precipitated by infusion of nut-galls, and by
chlorine ; by the last only, after an interval of several days. It
was neither precipitated by nitric acid, ammonia, nor corrosive
sublimate.
The portion of residue of sweat insoluble in alcohol and
water, Anselmino considered as coagulated albumen. Four-
croy had announced the presence of urea in the sweat of the
horse, but Anselmino could discover no trace of it. The ashes
from the dried sweat of the horse consist of sulphates of potash
and soda, common salt, and chloride of potassium ; it contains
* Berzelius, Trait6 de Chimie, vii. 326.
526 LIQUID PARTS OF ANIMALS.
neither carbonate nor phosphate of an alkali, but a considerable
quantity of phosphates of lime and magnesia, with traces of per-
oxide of iron.
Henri and Chevalier extracted by alcohol and water the mat-
ter of respiration from the hair of cows.* They obtained,
1. A fatty matter.
2. A brownish-black matter.
3. A bitter substance soluble in water.
4. A yellow colouring matter, soluble in alcohol and water.
5. Carbonate and hippurate of soda.
Dr Donne assures us that, in a state of health, the skin and
the matter of perspiration is always acid.f Berthollet had ob-
served this many years ago, and concluded that the acid present
was the phosphoric. J
Thenard obtained acetic acid, and Berzelius has rendered it
probable that the true acid of sweat is the lactic. Though dogs
and cats do not sweat, yet their skin, according to Donne, is al-
ways acid, while that of rabbits and horses is alkaline. Donne
has observed that the matter of perspiration frequently becomes
alkaline during disease, especially during those of the chronic
kind.§
CHAPTER XX.
OF THE LIQUOR OF THE AMNIOS.
THE foetus in the uterus is enveloped in a peculiar membrane
or covering, to which anatomists have given the name oi amnios.
Within this amnios there is a liquid, distinguished by the name
of liquor of the amnios, which surrounds the foetus. This liquid
in women is a fluid of a slightly milky colour, a faint but not
disagreeable smell, and a saltish taste. The white colour is owing
to a curdy matter suspended in it, for it may be rendered tran-
sparent by filtration.
Its specific gravity, as determined by Vauquelin and Buniva,
is 1*005. || These chemists analyzed it in 1800. It was again
• Jour, de Pharm. xxv. 422. f Ann. de Chim. et de Phys. Ivii. 401.
J Jour, de Phys. xxviii. 275. § Ann. de Chim. et de Phys. Ivii. 401.
II Ann. de Chim. xxxiii. 270.
LIQUOR OF THE AMNIOS.
analyzed by Dr Bostock about tbe year 1812,* and by Fromherz
and Gugert in 1827.J
Fromherz and Gugert describe it as yellow, muddy, and hav-
ing a slight taste and smell. When perfectly fresh, it reddens
turmeric paper, but the red stain disappears as the paper dries,
showing that the free alkali present is ammonia. When evapo-
rated to dryness, it left, according to Vauquelin and Buniva, 1-2
per cent, according to Dr Bostock, 1'66, and according to
Fromherz and Gugert, 3 per cent, of residue.
It is coagulated when raised to the boiling point, or when mix-
ed with alcohol. Nitric and muriatic acids throw down from it
a copious precipitate, but acetic acid only occasions a slight pre-
cipitate, which Fromherz and Gugert consider as casein. Caus-
tic potash throws down grayish white flocks. Corrosive sublimate
gives a copious precipitate, which becomes red after an interval
of some minutes. With infusion of nut-galls it is precipitated
abundantly of a light-yellow colour. When the liquor of the
amnios is distilled in glass-vessels, till one-fourth of it has passed
over into the receiver, we obtain a great deal of carbonate of am-
monia and a certain quantity of sulphuret of ammonium. When
the distillation is continued, more carbonate of ammonia passes
into the receiver, but no more sulphuret of ammonium.
When filtrated liquor amnii is treated with caustic potash,
phosphate of lime, and lime precipitate, both in combination with
an animal matter, by means of which they had been kept in solu-
tion. The potash unites with a portion of this matter, which
causes these earthy salts to precipitate.
When the liquor of the amnios is evaporated to dryness and the
residue treated with alcohol, a yellow extractive substance is dis-
solved, to which Fromherz and Gugert have given the name ofos-
mazome. The insoluble portion consists chiefly of albumen ; but con-
tains also casein and salivin. But of the presence of this last
substance they have given no evidence. By treating another
portion of the liquor amnii in another manner, they obtained ben-
zoic acid and urea. But the evidence of the presence of these
two substances is very incomplete. What they considered as nitrate
of urea was not subjected to any examination. They found also
in the liquor amnii much common salt ; phosphate, sulphate, and
* Schweigger's Jour, xxiii. 407. f Ibid. 1. 191.
5:28 LIQUID PARTS OF ANIMALS.
carbonate of soda ; sulphate of lime, and traces of salts of po-
tash.
According to Vauquelin and Buniva, the liquor amnii of a
woman was composed of,
Water, . 98'8
Albumen, . . -\
Common salt, soda, . > 1 2
Phosphate of lime, lime, )
100-
According to Dr Bostock, the constituents are,
Water, . 97-34
Albumen, . 0-16
Uncoagulable matter, 1-10
Salt, . 1-40
100-00
Four specimens of liquor amnii examined by Dr Rees, ex-
tracted from four individuals in the 7J month of gestation, con-
tained the same constituents. Specific gravity from 1-0086 to
1 -007. They all contained urea as a constituent. The caseous
matter floating in the liquid contained cholesterin. The salts are
the same as those of blood. The following table shows the con-
stituents of one specimen :
Specific gravity 1*008, strongly alkaline.
Water, . . 984-98
Albumen with trace of fatty matter, . 1-80
f Salts, 2-80, ^
Extract soluble in waterX Organic matter chief- V 6 '02
(. ly albumen, 3-22, J
Do. soluble m water/^ts, 2'8°> )
and alcohol, \ Organic matter chiefly lac- V 7-20
I. tic acid, urea, 4-4, J
100-00*
Fromherz and Gugert did not attempt a quantitative analysis of
liquor amnii, but merely to determine the different constituents
which it contained.
* Phil. Mag. (3d series,) xiii. 395.
3
LIQUOR OF THE AMNIOS.
While the foetus is in the uterus, a curdy- like matter is de
posited on the surface of the skin and on particular parts of the
body.
This matter is often found collected in considerable quantities.
It is evidently deposited from the liquor of the amnios, and of
course must exist in that liquor. It was subjected to a chemi-
cal examination by Vauquelin and Buniva, and also by From-
herz and Gugert.
Its colour is white and brilliant, it has a soft feel, and very
much resembles new-made soap. It is insoluble in water, alco-
hol, and oils. Pure alkalies dissolve it partially, and convert it
into a kind of soap. On burning coals it decrepitates, becomes
dry and black, gives out oily vapours, and leaves a residue very
difficult to incinerate. From these properties Vauquelin and
Buniva were led to consider it as a kind of fat.
Fromherz and Gugert digested it repeatedly in ether, and left
the ether to spontaneous evaporation. Brilliant white plates
were deposited, which had neither taste nor smell. They were
insoluble in water, but dissolved in boiling alcohol, and the so-
lution was neutral. They did not melt, though heated to 212°,
and when decomposed no carbonate of ammonia was given off.
When boiled with potash ley this substance could not be convert-
ed into soap. Fromherz and Gugert consider it as cholesterin.
The residue left by the ether was treated with cold water, and
as that substance did not seem to act, the water was raised to the
boiling temperature. The solution was yellowish and quite trans-
parent. Being evaporated to dryness the residue was insoluble
in alcohol. It had an alkaline reaction and possessed the cha-
racters of salivin. When incinerated it left a little carbonate of
soda.
When the curdy matter is digested directly in water, without
being previously treated with ether, salivin and carbonate of so-
da are dissolved ; but no albumen.
After the curdy matter has been treated with ether and boil-
ing water, a white flocky matter remains, which possesses the
following characters : When heated it gave out much carbonate
of ammonia. It was insoluble in alcohol, ether, and cold water.
When boiled about an hour in water a small portion of it was
dissolved. The solution was precipitated by infusion of nut-galls,
nitrate of silver, and protonitrate of mercury. Caustic alkali,
while cold, scarcely dissolves it ; but when it is boiled in dilute
L 1
530 LIQUID PARTS OF ANIMALS.
alkaline ley it is partially dissolved, and the solution is precipi-
tated by muriatic acid white. Sulphuric acid mixed with twice
its weight of water gives this substance a dark-red colour, but
does not dissolve it. From these characters Fromherz and Gru-
gert conclude that the insoluble portion of the caseous matter
from liquor amnii is albumen.
Thus it appears that the constituents of the caseous matter are,
Cholesterin. Carbonate of soda.
Salivin. Phosphate of lime.
Coagulated albumen.
II. The liquor amnii of the cow was also examined by Vau-
quelin and Buniva. But there is reason, from the subsequent
experiments of Lassaigne, to conclude that these chemists con-
founded together in their experiments the liquor of the amnios
and of the allantois. We have, however, an examination of the
true liquor amnii of the cow by Lassaigne in 1821,* and by
Proutf ^ 1815.
The liquor amnii examined by Dr Prout had been taken from
the uterus of a cow slaughtered in an early period of her gesta-
tion. It had a yellowish colour, with the appearance of very mi-
nute shining particles floating in it. Smell fragrant, something
like that of new milk or butter. Taste bland and sweetish like
fresh whey. Foamed a good deal when shaken. Did not af-
fect litmus or turmeric paper. Specific gravity 1O13. It con-
tained a very sensible quantity of the sugar of milk, which sepa-
rated in crystals from it when it had been concentrated by eva-
poration. It coagulated partially by heat ; some flakes fell, and
the liquid was left nearly transparent and colourless. Acetic
acid produced no coagulation, and prevented it from coagulating
by heat. Hence it contained albumen. Chloride of barium
produced a copious white precipitate. Dr Prout analyzed it
and obtained,
Water, ...... .' 977-0
Albumen, , j. &, &?* v 2-6
Substances soluble in alcohol, li fciii 16-6
Substances soluble in water, chiefly ^
sulphate of soda ? and other salts, v 3*8
Also sugar of milk, J
£ 1000-0
» Ann. de Cbim. et de Phys. xvii. 300. f Annals of Philosophy, v. 416.
LIQUOR OF THE ALLANTOIS. 531
The principles soluble in alcohol were of a brown colour ; and
seemed to consist in part of the lactates ; but chiefly of a pecu-
liar substance, having considerable resemblance in its properties
to the external brown parts of roasted veal.
The liquor amnii of the cow examined by Lassaigne differed
somewhat in its properties from the preceding, owing probably
to the different periods of gestation at which it was procured.
It had a yellowish colour, was viscid and sensibly alkaline. The
constituents extracted from it by Lassaigne (not reckoning the
water) were the following :
Albumen. Chloride of potassium.
Mucus. Carbonate of soda.
Yellow matter of bile. Phosphate of lime.
Common salt.
III. Lassaigne likewise analyzed the liquor amnii of a mare,
and obtained from it the following substances :*
Mucus. Common salt.
Albumen, (little.) Chloride of potassium.
Osmazome. Carbonate of soda.
Yellow matter. Phosphate of lime.
CHAPTER XXL
OF THE LIQUOR OF THE ALLANTOIS.
THE foetus in the uterus is enveloped in several successive
membranes. The outermost is called the chorion. Below this,
especially in quadrupeds, is a second membrane called the al-
lantois ; while the third or innermost membrane is called the
amnios. Both the allantois and the amnios contain a quantity
of liquid. The characters and constituents of the liquor amnii
have been given in the last chapter. At present we shall treat
of the liquor of the allantois.
The only chemist, so far as I know, who has turned his atten-
tion to this subject, is Lassaigne. In 1821, he published an ana-
lysis of the liquor of the allantois of the cow and the mare.f
Vauquelin and Buniva may have examined the liquor of the al-
* Ann. de Cliim. et de Phys. xvii. p. 303. f Ibid. xvii. 296, 303.
532 LIQUID PARTS OF ANIMALS.
lantois of the cow ; but it is more probable that in their analysis
the two liquors had been mixed together.
The liquor of the allantois of the cow is transparent, has a
fawn-yellow colour, and a taste slightly bitter and saline. It
reddened litmus-paper, and had a specific gravity of 1-0072.
When evaporated in a porcelain basin, a brownish pellicle form-
ed on its surface, and precipitated in flocks. This substance
possessed the following properties :
It was insoluble in water, alcohol, and diluted acids. It dis-
solved readily in alkalies. When ignited it blackened, swelled
up, and emitted the odour of burning horn. When incinerated
it left a grayish ash composed of phosphates of lime and magne-
sia. These characters show that the coagulated matter was al-
bumen.
When the liquid was evaporated to the tenth part of its ori-
ginal volume, and left in a cool place for twelve hours, it did
not deposit crystals. Being now treated with boiling alcohol, it
was separated into two portions : the one brown and viscid did
not dissolve ; while the other, which was brownish-yellow, dis-
solved in the alcohol.
When the alcoholic solution was evaporated it left a yellowish-
brown acid matter, having the smell and taste of beef-tea.
Being left at rest for twenty-four hours confused crystals were
deposited, which were white, and had a pearly lustre, and which
were easily freed from the colouring matter by washing them in
cold water. These crystals constituted the substance called am-
niotic acid by Vauquelin and Buniva. The name was changed
to allantoic acid by Lassaigne, and to allantoin by Wohler and
Liebig, because they did not find it to possess acid characters.*
The alcoholic extract from which the allantoin had been sepa-
rated still reddened litmus-paper. It had a deep-brown colour,
and a smell and taste similar to that of the juice of roasted meat.
Lassaigne considered it as a mixture of osmazome and lactic acid.
When calcined in a crucible it left a grayish-white ash, partly
soluble in water. The liquid being evaporated gave crystals
of common salt mixed with a little carbonate of soda. The por-
tion of the ashes insoluble in water was phosphate of lime. Be-
sides these constituents the portion dissolved in alcohol contained
some sal-ammoniac.
* The properties of this substance have been described in the Chemistry of
Vegetable Bodies, p. 212.
LIQUOR OF THE ALLANTOIS. 533
The portion of the extract insoluble in alcohol was dissolved
in water, and the solution left in repose in a cold place ; but no
crystals were deposited even after an interval of several days.
It was not precipitated by muriatic acid ; nitrate of bary tes threw
down a copious white powder insoluble in nitric acid ; lime- wa-
ter occasioned a white flocculent precipitate, while infusion of
nut-galls and acetate of lead threw down copious coloured pre-
cipitates. When incinerated, it left a good deal of sulphate of
soda and phosphate of soda, with some phosphates of lime and
magnesia. The following were the substances extracted from
the liquor of the allantois of a calf by Lassaigne :
Albumen. Sal-ammoniac.
Osmazome. Common salt.
Mucus. Much sulphate of soda.
Allantoin. Phosphate of soda.
Lactic acid and lactate of Phosphates of lime and mag-
soda, nesia.
Lassaigne also examined the liquor of the allantois of a mare,
but could detect in it no allantoin. The following were the sub-
stances which he obtained from it :
Mucus. Common salt.
Albumen. Chloride of potassium.
Osmazome. Much sulphate of potash.
Lactic acid. Phosphates of lime and magnesia.
M. Lassaigne had already, in 1819, examined the soft white
viscid matter found in the liquor of the allantois of a calf, especi-
ally towards the period of gestation, and known to veterinary
surgeons by the name of hippumanes.*
Cold water extracted from it only a little albumen and com-
mon salt. Alcohol and ether were incapable of dissolving any
part of it. When heated in caustic potash, it dissolved, with the
exception of a white crystalline powder, which constituted 27
per cent, of the original matter. The matter dissolved by the
potash being thrown down by an acid possessed the characters of
mucus. The white powder was oxalate of lime.
* Ann. de Chim. et de Phys. x. 200.
534 LIQUID PARTS OF ANIMALS.
CHAPTER XXII.
OF PUS.
THE liquid called pus is secreted from the surface of an in-
flamed part, and usually moderates and terminates the inflam-
mation. It assumes different appearances according to the state
of the sore. When it indicates a healing sore, it is called
healthy or good- conditioned pus. Unfortunately this liquid has
not hitherto been subjected to a rigid chemical examination.
The following are the only two analyses of pus made by any
modern chemist, and they are imperfect : I. That of pus from an
empyema by MM. Wilhelm and Martius in 1837. The patient
was a miller in the hospital of Erlangen, who had pleuropneu-
monia, with hepatization of the left lobe of the lungs. The pus
was extracted by an operation, and amounted to 153 German
pounds.
It was destitute of smell, thick in its consistence, and had a
dirty greenish-gray colour. Being examined by reagents, the
following phenomena were observed :
1. Litmus-paper was slightly reddened.
2. When agitated with ether, the colour became darker, and
the ether assumed a yellowish colour.
3. When mixed with absolute alcohol, many fine white flocks
separated, which could not be again taken up by agitation. The
alcoholic liquid gradually assumed a yellowish colour.
4. When dropped into water, it sank to the bottom, and by
agitation it constituted a muddy liquid.
5. Being mixed with an excess of caustic ammonia, it was
changed into a muddy liquid, from which white flocks were pre-
cipitated. The supernatant liquid was greenish-yellow.
6. An excess of acetic acid gave a muddy liquid having a
peach-blossom colour.
7. Nitric acid added in excess gave a muddy yellowish-green
liquid.
8. When heated in a platinum spoon, it swelled very much.
When evaporated to dryness, it left a black residue, and gave
out a smell like that of burning flesh.
* Ann. der Pharm. xxiv. 79.
PUS. 535
To determine its composition, it was mixed with ether, agitat-
ed and raised to the boiling temperature. The ether was then
allowed to cool and passed through a filter, which it did very
slowly. The etherial solution was yellowish, and had a specific
gravity of 1-11155 at the temperature of 50°. When examined
by reagents, it exhibited the following properties :
1. Caustic ammonia threw down a few white flocks.
2. Nitric acid ; no apparent change.
3. Chloride of platinum threw down yellowish flocks.
4. Acetate of silver, copious white flocks redissolved by the
addition of ammonia,
5. Chloride of gold threw down a yellowish precipitate.
6. Nitrated suboxide of mercury threw down an abundant
yellowish-white precipitate in flocks.
7. Neutral persulphate of iron a reddish-yellow precipitate.
8. Acetate of lead a copious precipitate in white flocks.
9. Nitrate of barytes a white precipitate.
10. Tincture of nut-galls a very copious reddish-yellow preci-
pitate.
11. Isinglass produced no change.
After these trials, the etherial solution was evaporated to the
consistence of an extract in a gentle heat. It was yellowish-
brown, and smelled like soup. It could not be made perfectly
dry over the water-bath. A portion of it was burnt in a porce-
lain crucible. It emitted the smell of burning horn. The
charry residue was digested in dilute muriatic acid. It dissolv-
ed with effervescence, except a little charcoal. The solution was
not affected by sulphuretted hydrogen. Chloride of ammonium
and ammonia being added in excess, a copious white precipitate
fell, which was chiefly phosphate of lime. Some lime was also
present, which was thrown down by oxalate of ammonia. It con-
tained also a little magnesia. They suspected likewise the pre-
sence of soda. This was not fully proved, but the presence of
potash was ascertained. When treated with caustic potash, am-
monia was given out. Thus the bases found in the pus were
lime, magnesia, potash, soda, and ammonia. But the ammonia
might have been formed by the action of the potash on the or-
ganic matter of pus.
The acid which existed in the pus was a mixture of phospho-
ric and muriatic. It contained no sulphuric acid nor nitric acid.
536
LIQUID PARTS OF ANIMALS.
To determine whether it contained lactic acid, so common in
animal fluids, the dried extract was digested in alcohol of 0-870.
The alcohol, after being separated by the filter, was strongly co-
loured, and reacted as an acid. It was mixed with sulphuric
acid diluted with alcohol, which caused a crystalline precipitate
of sulphate of soda and potash. The filtered liquid was digested
with carbonate of lead, till it ceased to be precipitated by chic-
ride of barium. It was now distilled, after separating the lead
by sulphuretted hydrogen. What came over contained no acid,
showing the absence of acetic acid from the pus. What remain-
ed in the retort had the consistency of a syrup, was of a dark-
brown colour, and strongly reddened litmus-paper. It was di-
luted with water, and boiled with carbonate of zinc, as long as
any carbonic acid was disengaged. The excess of oxide of zinc
was then removed by the filter. The liquid, after being digested
with some animal charcoal, was evaporated, and left a crust of
lactate of zinc, which is exceedingly soluble in water. The
oxide of zinc was thrown down by carbonate of potash, the po-
tash by tartaric acid, and the excess of tartaric acid by carbonate
of lead. The lead being removed by sulphuretted hydrogen and
the liquid evaporated, a colourless acid syrup was obtained, pos-
sessing all the properties of lactic acid.
The slimy matter not taken up by the alcohol contained fat,
gelatin, and some albumen.
A portion of pus was left in contact of ether for six months.
It was converted into a cheesy magma, over which the yellow
ether floated. The ether contained in solution much yellow fat
of the consistence of butter.
The present opinion of physiologists is, that the globules con-
stituting pus are nothing else than the globules of blood modi-
fied by the inflammatory process. Many experiments have been
made by M. Gendrin and Mr Gulliver to prove the truth of this
opinion.*
II. Dr Becquerel made an imperfect analysis of pus from an
abscess, the result of which was as follows :f It was white, with
a shade of yellowish-green, opaque, very thick and viscid, and
having a peculiar smell. With water it formed an emulsion,
from which the pus precipitated very slowly to the bottom in
white clots. The water is clear and limpid, but it had dissolved
* Phil. Mag. (third series), xiii. 198. t Semeiotique des Urines, p. 108.
ANIMAL POISONS. 537
the salts of the pus, consisting of sulphates, phosphates, and chlo-
rides, and also a notable quantity of albumen, coagulated by ni-
tric acid or heat. With ammonia pus forms a kind of soap.
When agitated with ether and the mixture left at rest, it was di-
vided into two strata. The undermost was clear and transparent,
and contained the salts and albumen of the pus ; the uppermost,
thick and thready, contained the solution of the fatty matters and
the globules. When examined by the microscope it is found to
contain a great n amber of globules, having a diameter varying
from j^th to 1FVs th of an inch. When treated by acetic acid
and examined by the microscope, it was found that the outermost
coat of the globules had been dissolved, leaving the internal
nucleus, which often subdivided itself into several smaller glo-
bules- It dissolved completely, though slowly, in ammonia.
Becquerel gives the following characters to enable us to dis-
tinguish mucus from pus.
Mucus. Pus.
1. Viscid. 1. Viscid and thick.
2. Transparent or opaline. 2. Opaque, yellowish-white.
3. Neutral. 3. Alkaline.
4. Very little fatty matter. 4. Much fatty matter.
5. Very little altered by am- 5. Made gelatinous by am-
monia, monia, and finally dissolved.
6. Charred in a spirit-lamp, giv- 6. Burns in a spirit-lamp with
ing out occasionally a slight a lively flame.
flame.
7. Before the microscope, com- 7. Do. Globules of a diame-
posed of thin plates, with oc- ter from 7^5 o^1 to i-sWn
casional globules. of an inch in diameter.
CHAPTER XXIII.
OF ANIMAL POISONS.
SEVERAL animals are furnished with liquid juices of a poison-
ous nature, which, when poured into fresh wounds, occasion the
disease or death of the wounded animal. Serpents, bees, scor-
pions, spiders, are well known examples of such animals. The
chemical properties of the*se poisonous juices deserve peculiar at-
538 LIQUID PARTS OF ANIMALS.
tention ; because it is only from such an investigation that we
can hope to explain the fatal changes which they induce on the
animal economy, or to discover an antidote sufficiently powerful
to counteract their baneful influence. Unfortunately the task is
difficult, and perhaps surpasses our chemical powers. For the
progress already made in the investigation, we are indebted
chiefly to the labours of Fontana.
1. The poison of the viper is a yellow liquid, which lodges in
two small vesicles in the animal's mouth. These communicate
by a tube with the crooked fangs, which are hollow and termi-
nate in a small cavity. When the animal bites, the vesicles are
squeezed, and the poison forced through the fangs into the wound.
This structure was partly observed by Redi, an Italian philoso-
pher ; and his discoveries were completed and confirmed by the
experiments and observations of Francini,* Tysson,f Mead,| and
Fontana.
This poisonous juice occasions the fatal effects of the viper's
bite. If the vesicles be extracted, or the liquid prevented from
flowing into the wound, the bite is harmless, If it be infused into
wounds made by sharp instruments, it proves as fatal as when
introduced by the viper itself. Some of the properties of this
liquid were pointed out by Mead ; but it was Fontana who first
subjected it to a chemical examination, sacrificing many hundred
vipers to his experiments. The quantity contained in a single
vesicle scarcely exceeds a drop.
It has a yellow colour, has no taste ; but when applied to the
tongue occasions numbness. It has the appearance of oil be-
fore the microscope, but it unites readily with water. It pro-
duces no change on vegetable blues.
When exposed to the open air, the watery part gradually eva-
porates, and a yellowish-brown substance remains, which has the
appearance of gum-arabic. In this state it feels viscid like gum
between the teeth ; it dissolves readily in water, but not in alco-
hol ; and alcohol throws it down in a white powder from water.
Neither acids nor alkalies have much effect upon it. It does not
unite with volatile oils nor sulphuret of potash. When heated
it does melt, but swells, and does not inflame till it has become
black. These properties are similar to the properties of gum,
* New Abridg. of the Phil. Trans, ii. 8. f PhH- Trans. Vol. xii.
| Mead on Poisons, p. 35.
ANIMAL POISONS. 539
and indicate the gummy nature of this poisonous substance.
Fontana made a set of experiments on the dry poison of the vi-
per, and a similar set on gum arabic, and obtained the same re-
sults.
From the observations of Dr Russel, there is reason to believe
that the poisonous juices of the other serpents are similar in their
properties to those of the viper.
This striking resemblance between gums and the poison of the
viper, two substances of so opposite a nature in their effects upon
the living body, is a humiliating proof of the small progress we
have made in the chemical knowledge of these intricate sub-
stances. The poison of the viper, and of serpents in general, is
most hurtful when mixed with the blood. Taken into the sto-
mach it kills if the quantity be considerable. Fontana has as-
certained that its fatal effects are proportional to its quantity,
compared with the quantity of the blood. Hence the danger di-
minishes as the size of the animal increases. Small birds and
quadrupeds die immediately when they are bitten by a viper ;
but to a full -sized man the bite seldom proves fatal.
Ammonia has been proposed as an antidote to the bite of the
viper. It was introduced in consequence of the theory of Dr
Mead, that the poison was of an acid nature. The numerous
trials of that medicine by Fontana robbed it of all its celebrity ;
but it has been lately revived and recommended by Dr Ramsay
as a certain cure for the bite of the rattlesnake.*
2. The common toad (Rana bufo) has been considered as poi-
sonous by the common people in all ages. But the opinion was
rejected by naturalists as a vulgar prejudice till the subject was
investigated by Dr Davy.f
This poisonous liquid is seated chiefly in the integuments, in
follicles, in the cutis vera beneath the cuticle, and the coloured
rete mucosum. These follicles are largest and most numerous
near the shoulders and about the neck of the animal ; yet they
are pretty generally distributed, and even on the extremities.
Pressure being applied to the skin a yellowish thick fluid exudes,
* Phil. Mag. xvii. 125. The reader will find an interesting dissertation on
the different remedies applied to the cure of the rattlesnake in the Amer. Trans.
Vol, iii. p. 100, by Dr Smith Barton. The observations of Fontana in his trea-
tise on poisons deserve particular attention.
t Phil. Trans. 1826, p. 227.
540 LIQUID PARTS OF ANIMALS.
and occasionally spurts to a considerable distance. Dr Davy
found it possessed of the following properties :
The greater part of it is soluble in alcohol and water. The
aqueous solution is slightly viscid, and does not pass easily through
a common filter. It is not precipitated by acetate of lead, and
only very slightly by corrosive sublimate. When the aqueous
or alcoholic solution is evaporated to dryness, it leaves a yellow
transparent substance, having a slight but peculiar smell, and a
slightly bitter and very acrid taste, acting on the tongue like the
extract of aconite prepared in vacuo. It even occasions a smart
sensation when applied to the skin of the hand, and its effect
lasts two or three hours. When heated it readily melts, burns
with a bright flame, and does not emit an ammoniacal smell. It
neither reacts as an acid nor an alkali. Caustic ammonia dissolves
it. The solution remains acrid. Nitric acid also dissolves it,
and the solution has a purple colour. When neutralized by an
alkali the solution is but slightly acrid, and seems to have un-
dergone partial decomposition.
Dr Davy conceives that the small portion of the poison of the
toad which is insoluble in water and alcohol, is a variety of albu-
men. But he does not state the reasons on which this opinion is
founded.
Notwithstanding the acridity of this substance, it would appear
from Dr Davy's experiments that it is not injurious when intro-
duced into the blood. A chicken punctured with a lancet dipt
in it received no injury. Dr Davy says that he detected a not-
able quantity of it in the bile of the toad, in the viscid liquid lu-
bricating the tongue, and in the blood and urine of the animal.
But he does not mention the characters by which its presence in
these liquids was recognized.
Dr Davy conceives that this liquor, (the venomous nature of
which does not seem well established by his experiments,) may
serve to protect the animal from the attacks of carnivorous ani-
mals. He thinks also that its secretion may contribute to the
discharge of carbon from the blood; and conceives that this
opinion is strengthened by a peculiarity in the distribution of the
pulmonary artery, which he describes.
The poisonous liquid of the toad had been subjected to expe-
riment by M. Pelletier in 1817.* His results agree, on the
* Jour, de Pharmacie, iii, 537.
ANIMAL POISONS. 541
whole, with those of Dr Davy, though in some circumstances
they differ. He found that when exposed to the air it soon be-
came solid, and that if it had been put into a watch-glass it might
in a few minutes be taken off under the form of transparent
scales. It was exceedingly acrid, both when liquid and solid,
and reacted strongly as an acid. With water it formed an emul-
sion. Cold alcohol had little action on it ; but it dissolved a
portion when assisted by heat, and assumed a fawn-colour. The
portion undissolved was white and destitute of taste and smell.
It resembled, according to Pelletier, the gelatinous membranes.
The alcoholic solution scarcely reddened litmus- paper, and lost
that property entirely when evaporated. As the alcohol was
driven off an oily matter separated, which became solid on cool-
ing. This matter was insoluble in water, little soluble in ether ;
but very soluble in alcohol. Its taste was very bitter ; but it was
neither acrid nor caustic. It reacted slightly as an alkali. The
acid of the poison of the toad appears from Pelletier's experi-
ments to be very volatile and only partially combined with a base-
Hence probably the reason why it was not detected by Dr Davy
The gelatinous matter of the poison was insoluble in cold wa-
ter ; but soluble in hot water, to which it communicated a gela-
tinous consistence. But, as it was neither precipitated by chlo-
rine nor by infusion of nut-galls, it is obvious that it was a differ-
ent substance from either collin or chondrin.
3. The venom of the bee and the wasp is a liquid contained in
a small vesicle forced through the hollow tube of the sting into
the wound inflicted by that instrument.* From the experiments
of Fontana we learn that it bears a striking resemblance to the
poison of the viper. That of the bee is much longer in drying
when exposed to the air than the venom of the wasp.
4. The poison of the scorpion resembles that of the viper also.
But its taste is hot and acrid, which is the case also with the ve-
nom of the bee and the wasp.
5. No experiments upon which we can rely have been made
upon the poison of the spider tribe. From the rapidity with
which 'these animals destroy their prey, and even one another,
we cannot doubt that their poison is sufficiently virulent. f
* See a curious account of the structure of the sting by Dr Hooke in his Mi-
crographia.
f Dr Mead's romantic account of the bite of the tarantula will entertain the
reader. See Mead on Poisons, p. 57.
LIQUID PARTS OF ANIMALS.
CHAPTER XXIV.
OF FECES.
THE excrementitious matter of animals, evacuated per anum,
consists of all that part of the food which cannot be employed for
the purposes of nutrition, considerably altered, at least in part,
and mixed or united with various bodies employed during diges-
tion to separate the useless parts of the food from the nutritious.
An accurate examination of these matters has long been wished
for by physiologists, as likely to throw much new light on the
process of digestion. For if we knew accurately the substances
which were taken into the body as food, and all the new substan-
ces which were formed by digestion ; that is to say, the compo-
nent parts of chyle and of excrement, and the variation which
different kinds of food produce in the excrement, it would be a
very considerable step towards ascertaining precisely the changes
produced on food by digestion.
Some of the older chemists had turned their attention to the
excrements of animals ;* but no discovery of importance reward-
ed them for their disagreeable labour. Vauquelin has ascertain-
ed some curious facts respecting the excrementitious matter of
fowls. In the summer of 1806, a laborious set of experiments
on human feces was published by Berzelius, undertaken, as he
informs us, chiefly with a view to elucidate the function of diges-
tion.f About two years before, Thaer and Einhof had publish-
ed a similar set of experiments on the excrements of cattle ; made
chiefly to discover, if possible, how they act so powerfully as ma-
nure.:): I shall in this chapter give a view of the results obtained
by these different chemists.
I. The appearance of human feces requires no particular de-
tail. Their colour is supposed to depend upon the bile mixed
with the food^in the alimentary canal. When too light, it is
supposed to denote a deficiency of bile ; when too dark, there is
supposed to be a redundancy of that secretion. The smell is
fetid and peculiar, which after some time gradually changes in-
* Van Helmont's Gustos Errans, Sect. vi. Opera Helmont, p. 14" Neu-
mann's Works, p. 585.
t Gehlen's Jour. vi. 509. J Ibid. iii. 276.
FECES. 543
to a sourish odour. The taste is sweetish bitter. The colour of
vegetable blue infusions is not altered by fresh feces, indicating
the absence of any uncombined acid or alkali.*
1. The consistency of human feces varies considerably in dif-
ferent circumstances ; but at a medium, they may be stated to
lose three-fourths of their weight when dried upon a water-bath.f
2. They do not mix readily with water ; but by sufficient agi-
tation and maceration, they may be diffused through it. The
liquid, in this state, being strained through a linen cloth, leaves
a matter of a grayish-brown colour, retaining a peculiar odour,
which adheres long and obstinately to all those substances that
come in contact with this residue. When dried, this substance
exhibits the remains of vegetable matters used in food, and per-
haps also of some animal matters. Its quantity amounts to about
seven per cent, of the feces.J
3. The strained liquid deposited, on standing, a yellowish-
green slimy matter, which was separated by the filter. It amount-
ed when dry to fourteen per cent, of the feces employed. From
the numerous experiments of Berzelius upon this matter, it ap-
pears to be composed chiefly of three substances: 1. A fatty
matter, separated by means of alcohol, which possesses many
properties in common with picromel, and which Berzelius con-
siders as that substance a little altered. 2. A peculiar yellow-
coloured substance, dissolved by water after the fatty matter is
removed. This substance Berzelius compares to gelatin ; but it
appears to be rather more closely allied to mucus, or, at least, to
contain mucus as a constituent. It dissolves in water, but not in
alcohol ; tannin makes its solution muddy, but occasions no pre-
cipitate ; acetate of lead occasions a copious white precipitate,
but does not deprive the solution of its yellow colour. It soon
runs to putrefaction, exhaling the odour of putrid urine. 3. A
greenish-gray residue, insoluble both in water and alcohol, and
leaving, when incinerated, some silica and phosphate of potash. §
4. ,The liquid which passed through the filter was at first light-
yellow ; but by exposure to the air it became brown, which gra-
dually deepened in colour, till the solution grew at last muddy.
When concentrated by evaporation, small transparent crystals
made their appearance : which proved, on examination, to be
crystals of ammonia-phosphate of magnesia. The solution, on
* Gehlen's Jour. vi. 512. f Ibid. vi. 535. J Ibid. vi. 513. § Ibid. 526—534.
544 LIQUID PARTS OF ANIMALS.
examination, was found to contain the following substances : 1.
Albumen, which was obtained by mixing the concentrated solu-
tion with alcohol. The precipitate consisted of a mixture of al-
bumen and phosphoric salts. The albumen obtained from 100
parts of feces amounted only to 0-9 parts. 2. Bile. By this
Berzelius understood a mixture of biliary matter and soda. The
presence of this substance was inferred from the nature of the
precipitate obtained by acids, and the salt of soda obtained by
evaporating the residue. The quantity contained in 100 parts
of feces was 0-9. 3. A peculiar substance, of a reddish-brown
colour, soluble both in water and alcohol. Acids give it an in-
tense brown colour. A small quantity of tannin throws it down
of a red colour and in a pulverulent form ; a large quantity
throws it down in grayish-brown flakes. It is precipitated by mu-
riate of tin, nitrate of silver, and acetate of lead. When heated
it melts and emits the smell of ammonia. It leaves behind it,
when burnt, traces of soda and of phosphoric salts. Berzelius
supposes that this substance is formed from the biliary matter,
by some change which it undergoes after the feces are exposed
to the air. The quantity of it obtained from 100 part of feces
was 2 -7 parts. 4. Various salts : these in all, from 100 parts of
feces (including the ammonio-phosphate of magnesia), amounted
to 1-2 parts. Their relative proportions were as follows :
Carbonate of soda, 'T.>.:i«;^ . .. 35
Common salt, K.v: [j* fa *'•'*<.* 4
Sulphate of soda, . 2
Ammonia-phosphate of magnesia, 2
Phosphate of lime, . . 4
Such are the constituents of human feces, according to the ex-
periments of Berzelius. The following table exhibits the result
of his analysis :*
Water, 1 „ ' . . 73-3
Vegetable and animal remains, . . 7*0
Bile, . ! . - . . ^V 0-9
Albumen, \V- . »''•••:"' V : 0'9
Peculiar and extractive matter, = v , 2*7
Salts, ,,,: j . . . 1-2
Slimy matter; consisting of biliary matter, pe- 1 , , ^
culiar animal matter, and insoluble residue, /
100-0
* Gehlen's Jour. vi. 536.
4
FECES. 545
IL The excrementitious matter examined by Thaer and Ein-
hof was that of cattle fed at the stall, chiefly on turnips. It had
a yellowish- green colour, a smell somewhat similar to that of
musk, and but little taste. Its specific gravity was 1*045. It
did not alter vegetable blues, and of course contained no uncom-
bined acid or alkali.
1. Sulphuric acid, when mixed with this matter, developesthe
odour of acetic acid ; but Thaer and Einhof have shown that this
acid does not exist in the feces, but is formed by the action of the
sulphuric acid. The pure alkalies, nitric and muriatic acids,
produce little change on the feces of cattle, at least when not as-
sisted by heat
2. When 100 parts are dried on a steam-bath, they leave 28 J
of solid matter.
3. When eight ounces, or 3840 grains, were diffused through
water, they let fall a quantity of sand, weighing 45 grains.
4. The watery solution, being strained through a linen cloth,
left 600 grains of a yellowish fibrous matter, which possessed the
properties of the fibrous matter of plants.*
5. The liquid, on standing, deposited a slimy substance, which
was separated by filtration. It weighed when dry 480 grains.
To this matter the feces owe their peculiar colour and smell. It
was insoluble in water and alcohol. When heated it smelled
like ox bile. It burnt like vegetable matter. Alkalies scarcely
affected it. Sulphuric acid developed the odour of acetic acid.
Chlorine rendered it yellow. Thaer and Einhof considered this
substance as the remains of the vegetable matter employed as
food by the cattle ; but it is extremely probable that it might
contain also a portion of picromel, as Berzelius detected that sub-
stance in similar matter from the human feces.
6. The filtered solution passed through colourless, but on ex-
posure to the air became in a few minutes wine-yellow and then
brown. When evaporated to dryness it left a brownish matter,
of a bitterish taste, and weighing 90 grains. It was soluble in
water, insoluble in alcohol, and precipitated from water by that
liquid. It was not precipitated by infusion of galls. The so-
lution was found to contain some phosphoric salts. The 90 grains
of residue, when heated, burnt like animal matter. They soon
ran into putrefaction, exhaling ammonia. f
* Gehlen, Hi. 286. f Ibid. iii. 287.
M m
546 LIQUID PARTS OF ANIMALS.
7. When evaporated to dryness and burnt, this excrementitious
matter left behind it an ash, which was found (not reckoning the
sand) to consist of the following salts and earths in the propor-
tion stated :*
Lime, . . .12
Phosphate of lime, . 12-5
Magnesia, ... 2
Iron, ... 5
Alumina with some manganese, . 14
Silica, ... 52
Muriate and sulphate of potash, . 1 -2
8. Thaer and Einhof made numerous experiments on the pu-
trefaction of cow-dung, both in close vessels and in the open air,
from which it would appear that the process resembles closely
the putrefaction of vegetable matter ; the oxygen of the air being
abundantly changed into carbonic acid.f
III. To Vauquelin we are indebted for an analysis of the fix-
ed parts of the excrements of fowls, and a comparison of them
with the fixed parts of the food ; from which some very curious
consequences may be deduced.
He found that a hen devoured in ten days 111 11 '843 grains
troy of oats. These contained,
Phosphate of lime, . 126-509 grains.
Silica, . ,j,.i. 219-548
346-057
During these ten days she laid four eggs ; the shells of which
contained 98*779 grains phosphate of lime, and 453-417 grains
carbonate of lime. The excrements emitted during these ten
days contained 175-529 grains phosphate of lime, 58'494 grains
of carbonate of lime, and 185-266 grains of silica. Consequent-
ly, the fixed parts thrown out of the system during these ten
days amounted to,
Phosphate of lime, . 274-305 grains.
Carbonate of lime, J.vl 511-911
Silica, U-i v . ftittoa 185-266
Given out, . 971-482
Taken in, . 356-057
Surplus, . 615-425
» Gehlen, iii. 321. t ^id. 295, 313.
FECES. 547
Consequently, the quantity of fixed matter given out of the sys-
tem in ten days exceeded the quantity taken in by 615-425
grains,
The silica taken in amounted to, . 219*548 grains.
That given out was only, . 185-266
Remain, 34-282
Consequently, there disappeared 34-282 grains of silica.
The phosphate of lime taken in was . 136-509 grains.
That given out was . . 274-305
137-796
Consequently, there must have been formed, by digestion, in
this fowl, no less than 137-796 grains of phosphate of lime, be-
sides 5 1 1 *9 1 1 grains of carbonate. Consequently, lime (and per-
haps also phosphorus) is not a simple substance, but a compound,
and formed of ingredients which exist in oat-seed, water, or air,
the only substances to which the fowl had access. Silica may
enter into its composition, as part of the silica had disappeared ;
but if so, it must be combined with a great quantity of some other
substance.*
These consequences are too important to be admitted without
a very rigorous examination. The experiment must be repeat-
ed frequently, and we must be absolutely certain that the hen
has no access to any calcareous earth, and that she has not di-
minished in weight ; because, in that case, some of the calcare-
ous earth, of which part of her body is composed, may have been
employed. This rigour is the more necessary, as it seems pretty
evident, from experiments made long ago, that some birds, at
least, cannot produce eggs unless they have access to calcareous
earth. Dr Fordyce found, that, if the canary bird was not sup-
plied with lime at the time of her laying, she frequently died,
from her eggs not coming forward properly.f He divided a
number of these birds at the time of their laying eggs into two
parties : to the one he gave a piece of old mortar, which the little
animals swallowed greedily ; they laid their eggs as usual, and
all of them lived ; whereas many of the other party, which were
supplied with no lime, died4
* Ann. de Chim. xxix. 61. f On Digestion, p. 25.
\ Ibid. p. 26.
548 LIQUID PARTS OF ANIMALS.
Vauquelin also ascertained, according to Fourcroy, that
pigeons' dung contains an acid of a peculiar nature, which in-
creases when the matter is diluted with water, but gradually
gives place to ammonia, which is at last exhaled in abundance. *
IV. The white matter voided by dogs who feed chiefly on
bones, was formerly used in medicine under the name of album
groRcum. It has not been examined by modern chemists, but is
supposed to consist in a great measure of the earthy part of the
bones used as food, f
V. M. Lassaigne,J in 1821, made some experiments on the
meconium from the foetus of a calf. He found in it the follow-
ing substances :
Mucus, Common salt,.
Green matter, Carbonate of soda,
Yellow matter, Phosphate of lime.
VI. In the year 1815, Dr Prout examined the excrements of
the Boa constrictor. $ This substance was solid, of a white colour*
inclining to yellow. The fracture was earthy. When it was
rubbed against a hard body, it left a white mark like chalk. Its
feel was rather more dry and harsh than that of chalk, and
it was more friable. The smell was faint and mawkish. The
specific gravity, 1-385. It was found composed of,
Uric acid, #«& T. . ; .:<n 9O16
Potash, >^!'> />:tv? t>4j(n . 3-45
Ammonia, *•">.-({ > «r.r w ?l:r;i > 1-70
Sulphate of potash with trace of )
1. /" U'i/O
common salt, . . J
Phosphate of lime, . ^
Carbonate of lime, . 0-80
Magnesia,
Animal matter ; viz. mucus and) 2 «.
a little colouring matter, j
100-00
These facts were confirmed by Dr Davy in 1817 1| and by Vau-
quelin in 1822.1F Dr Davy proved by dissection that the yel-
* Fourcroy, x. 70. f Neumann's Chemistry, p. 585.
| Ann. de Chim. et de Phys. xvii. 304. Ann. Ixxi. 128.
§ Annals of Philosophy, v. 413. || Phil. Trans. 1818, p. 302.
f Ann. de Chim. et de Phys. xxi. 440.
FECES. 549
lowish white matter examined was not the feces but the urine of
the serpent. It is voided once in from three to six weeks. Dr
Davy found the urine of four species of lizards, of the alligator,
the turtle, and the tortoise, similar in its consistence and consti-
tution to that of the serpent.
VIL The excrements of the Chamodeonis vulgaris were exa-
mined by Dr Prout in 1820.* They consisted partly of a fine
powder of a bright lemon yellow colour, and partly of lumps
composed of the same powder loosely agglutinated. They con-
sisted almost entirely of urate of ammonia and a little colouring
matter. Thus they resemble very closely the excrements of the
Boa constrictor. The food of the chamseleonis is said to con-
sist of the Lumbricus terrestris and the larvae of the Tenebria
molitor,
VIII. It was shown many years ago by Dr Wollaston that
the dung of fowls consists chiefly of uric acid. The dung, or ra-
ther the urine of carnivorous birds, is very similar in its constitu-
tion to that of the Boa constrictor.
The stomach often contains gaseous matters. A quantity of
gas extracted from the stomach was analyzed by Chevreul, and
found composed of,
Carbonic acid, . 43 volumes.
Sulphuretted hydrogen, 2
Oxygen, . . 4
Azotic, . . 31
Carburetted hydrogen, 20
lOOf
* Annals of Philosophy, xv. 471.
f Leuret and Lassaigne sur la Digestion, p. 1 25.
550 LIQUID PARTS OF ANIMALS.
CHAPTER XXV.
OF THE AIR CONTAINED IN THE SWIMMING BLADDER
OF FISHES.
MANY fish are furnished with a bladder filled with air, by means
of which they are supposed to rise or sink in the water. When
they wish to rise they are supposed to dilate their air-bladder ;
when they wish to sink they compress it. Whether this be the
use of the air-bladder of fishes is somewhat doubtful. Most fish
have a peculiar depth at which they almost always remain. Thus
the flat fish constantly affect the bottom of the sea, while there
are others that as constantly affect the surface. From the
observations of Biot it appears, that when a fish is suddenly
brought from a great depth towards the surface, the air-bladder
swells so much that the fish cannot again sink ; nay, it often
bursts ; arid the air making its way into the stomach, swells it
up, and forces it into the mouth or oesophagus. The air with
which these bladders is filled was first examined by Dr Priestley
in 1774. From his observations it appears that it varies in its
nature. The roach was the fish the air-bladder of which he ex-
amined. At first he found it filled with azote, but afterwards he
got a mixture of oxygen and azote. *
Fourcroy long after examined the air in the air-bladder of
the carp, and found it almost pure azote : and similar results
were obtained by other chemists. But by far the most complete
analysis of this kind of air has been made by Biot, while in Yviza
and Formentera, two islands a little to the south of Majorca and
Minorca. He was employed by the French government to pro-
long the meridian of France to the Balearean islands, and em-
braced the opportunity which presented itself to examine the air
in the bladders of the different species offish caught in the neigh-
bourhood of these islands. Next season he returned to the same
islands with Mr Laroche, who repeated and confirmed his pre-
ceding experiments.!
Biot found the air in the air-bladders a mixture of azotic and
oxygen gas in very variable proportions. No traces of hydrogen
* Priestley on Air, ii. 462.
f Biot's Memoirs are printed in the Mem. D'Arcueil, i. 252, and ii. 487.
AIR IN THE SWIMMING BLADDER OF FISHES. 551
gas could be detected ; nor was there any sensible quantity of car-
bonic acid. The proportion of oxygen gas was very various,
being sometimes very minute, and sometimes constituting almost
the whole of the gas. The air bladders of those fish which live
near the surface contained least oxygen gas, and the bladders of
those which were brought up from a great depth contained the
most. The following table exhibits the proportion of oxygen in
100 parts of the air in the different fish examined :
Names of the Fish. Prop, of Oxygen. Names of the Fish. Prop, of Oxygen.
Mugil cephalus (Linn.) Quant, insen. Scisena nigra, female, . 0-27
Ditto. . . Ditto. Ditto, male, . . 0-25
Mursenophishelena(Zacep.) Very little. Labrus turdus (Linn.) female, 0 24
Sparus annularis(Zinn.) female, 009 Ditto, male, . . 0-28
Ditto, male, . . Of08 Sparus dentex (Linn.) female, 0'40
Sparus sargus (Linn.) female, 0-09 Sphyraena spet, (Lacep.) 0-44
Ditto, male, . . 0-20 Sparus argenteus, . .0-50
Holocentrus marinus (Lacep.) 0-12 Sparus erythrinus, . . Much
Labrus turdus (Linn.) . 0*16 Holocentrus gigas, . . 0'69
Sparus melanurus (Linn.) 0-20 Gadus merluccius (Linn.) 0.79
Labrus turdus (Far. Linn.) 0'24 Trygla lyra (Linn.) . 0-87
The depth at which the fish in the preceding table are caught
increases gradually, as well as the proportion of oxygen, from
the beginning to the end of the table. The last-mentioned fish,
the Trygla lyra, is always caught at a very great depth. The ex-
periments of Laroche confirm the accuracy of this curious fact.
The mean result, furnished by all the fishes taken at a depth
greater than 150 feet, was 0*70 of oxygen ; while the mean re-
sult, furnished by the fish caught at less depths, was 0-29. This
superior purity is not owing to any superior purity in the air of the
water of the sea at great depths. The air obtained from sea
water, brought~up from a great depth, yielded 0*265 of oxygen,
while that from water taken at the surface was purer.
It is very remarkable that the air in the bladder of fishes,
taken near the surface, should be almost pure azote. But this
holds also with respect to fresh water fish. Thus Biot found the
air in the air-bladder of a carp to contain 0-03 of oxygen, while
that of a tench contained 0-16 ; and Geoffrey and Vauquelin
found the air in the air-bladder of pikes, loaches, and perches,
to contain 0-05 of oxygen. Humboldt likewise found very lit-
tle oxygen in the air-bladder of the Gymnotus electricus.
MORBID CONCRETIONS.
PART III.
OF MORBID CONCRETIONS.
SOLID bodies are apt to be deposited in various cavities, both
of the human body and of the inferior animals. These occasion
uneasiness frequently terminating in disease and death. These
concretions, so far as they have been investigated by chemists, may
be arranged under the six following heads : —
1. Urinary calculi. 4. Biliary concretions.
2. Gouty concretions. 5. Ossifications.
3. Salivary concretions. 6. Intestinal concretions.
These will be treated of successively in the six following chap-
ters.
CHAPTER I.
OF URINARY CALCULI.
IT is well known that concretions not unfrequently form in
the kidneys or bladder, and occasion one of the most dismal dis-
eases to which the human species is liable.
These concretions were distinguished by the name of calculi,
from a supposition that they are of a stony nature. Their ex-
istence must have been known from the very commencement of
medical science. The mode of extracting them by an operation
was known to the ancients, and is described by Celsus. Che-
mistry had no sooner made its way into medicine than it began to
exercise its ingenuity on the urinary calculi ; and various theo-
ries of their nature and origin were given. According to Pa-
racelsus, who distinguished them by the name of duelech, they
were intermediate between tartar and stone, * or were composed
of a mucilaginous tartar that floated in the blood-vessels. In
his fourth tract, De Elemento Aqua, cap. 8, he gives cha-
racters of duelech ; but they differ so much from those of urinary
calculi that it is not worth while to transcribe them. The school-
* De Morbis Tartareis, cap. 11.
UIUNAEY CALCULI. 553
men considered calculi as a peculiar mucilage concocted and pe-
trified by the heat of the body. These opinions were ably re-
futed by Van Helmont in his treatise De Lithiasi, which contains
the first attempt towards an analysis of urine and urinary cal-
culi ; and, considering the period when it was written, is certain-
ly possessed of uncommon merit. He demonstrates that the ma-
terials of calculi exist in the urine. He considers them as com-
posed of a volatile earthy matter, and the saline spirit of urine,
which coagulate instantaneously when they come in contact;
but which are prevented from combining in healthy people, by
what he calls scoria, which saturates the salt of urine. *
Boyle found calculi soluble in nitric, but insoluble in sulphuric
acid and muriatic acid and vinegar, f Thus showing the species
upon which his experiments had beeen made. Slave attempted
a chemical analysis of them. J Hales extracted from them a
prodigious quantity of air. He gave them the name of animal
tartar ; pointed out several circumstances in which they resem-
ble common tartar, and made many experiments to find a solvent
for them. § Drs Whytt and Alston pointed out alkalies, parti-
cularly lime, as the best solvents of calculi. The first attempt at
a description of human urinary calculi that I have met with was
by Dr Lewis in his notes on Neumann's Chemistry, published in
1759. ||
Such was the state of the chemical knowledge of urinary cal-
culi when Scheele published a set of experiments upon a collec-
tion of them, which he had made; in the Memoirs of the Stock-
holm Academy for 1 7 7 6. 1F All that he examined were of the same
nature. Scheele showed that they consisted of an acid, to which
the name of uric acid was given. He considered calculi as oily
salts composed of a mucilaginous matter with uric acid in excess.
To Scheele's paper an appendix was added by Bergman. He
also had been engaged in examining urinary calculi. Some he
found to agree in their nature with those of Scheele, while others
consisted chiefly of phosphate of lime.
Scarcely any addition was made to the discoveries of Scheele
» De Lithiasi, p. 21. Constituting an appendix to Van Helmont's Opera.
f Shaw's Boyle, iii. 557. J Phil. Trans, xvi. 140.
§ Veget. Statics, ii. 189.
|| Lewis's Neumann's Chemistry, p. 532.
^ Kongl. Vetenskiaps Acad. Hand. 1776, p. 327.
554 MORBID CONCRETIONS.
and Bergman till Dr Wollaston published his important paper
on urinary and gouty concretions in 1797. Mr Lane, indeed,
examined the action of heat on various calculi, and the quantity
of each dissolved in 48 hours in caustic potash.* About the year
1797, Brugnatelli published some observations on urinary calcu-
li.! Those which he examined he found partly soluble in water,
and he says that the portion dissolved was biphosphate of lime.
The portion not soluble in water was uric acid, and he says that,
when treated with nitric acid, a great part of it was converted
into oxalic acid.
Dr Wollaston, in his paper published in the Philosophical
Transactions for 1797 (p. 386), describes four new species of
calculi, which had been observed indeed before, but their chemi-
cal constitution was unknown till it was determined by Wollas-
ton. These were, 1. Fusible calculus. It had been observed by
Smithson Tennant, that when this calculus was exposed to the
action of the blowpipe, instead of being consumed like the uric
acid calculus of Scheele, it left a considerable residue, which fused
into an opaque white glass. Wollaston found that these calculi
contained brilliant crystals of ammonia-phosphate of magnesia,
which were usually mixed with phosphate of lime and some uric
acid. 2. Mulberry calculus. This name had been given by sur-
geons to a dark-coloured calculus with an uneven surface, bear-
ing some resemblance to a mulberry. Hence the name. Dr
Wollaston found that it consisted essentially of oxalic acid com-
bined with lime. The smooth calculus known by the name of
hemp-seed calculus, W ollaston found also to be chiefly oxalate of
lime ; but to contain phosphate of lime and some uric acid.
From the late investigations of Wohler and Liebig, it seems to
be very probable that the mulberry calculus is in reality a com-
pound of oxaluric acid and lime. 3. Bone earth calculus. This
calculus has a brown colour, is smooth, and composed of concen-
tric laminae, easily separated from each other. Before the blow-
pipe it is at first charred ; then becomes perfectly white, and
urged by the utmost heat of the blowpipe it fuses. It consists
essentially of phosphate of lime ; and differs from bone earth by
containing no carbonate of lime. 4. Calculi from the prostate gland.
These are small calculi having the colour and transparency of
* Phil. Trans. 1791, p. 223. t Ann. de Chim. xxviii. 52,
URINARY CALCULI. 555
amber. They consist of phosphate of lime tinged with the se-
cretion of the prostate gland.
About the commencement of the present century Fourcroy
and Vauquelin announced their intention of making a rigid ana-
lysis of all the calculi which they could procure, and invited me-
dical men to send them specimens. In this manner they obtain-
ed and examined about 600 different calculi. They found the
same substances which Wollaston had described, and likewise
urate of ammonia, and in two calculi a quantity of silica. It is
remarkable that, though Dr Wollaston's experiments had been
published three years before, and in the Philosophical Transac-
tions, a copy of which is regularly transmitted to the Academy
of Sciences, of which Fourcroy was a member ; yet Fourcroy,
who drew up the account of the experiments, takes no notice
whatever of the previous labours of Wollaston, who had antici-
pated almost all the discoveries which they made respecting the
constitution of calculi.*
In the year 1808,| Mr Brande examined the calculi in the
Hunterian Museum, at that time in the possession of Sir Everard
Home, but now the property of the University of Glasgow. He
informs us that he examined 150 calculi, and found their consti-
tution as follows :
1 6 were composed of uric acid.
46 of uric acid with a small portion of phosphates.
66 of phosphates with a little uric acid.
12 composed of phosphates entirely.
5 of uric acid with the phosphates and nuclei of
oxalate of lime.
6 of oxalate of lime chiefly.
150
Mr Brande endeavours to prove that the urate of ammonia
found by Fourcroy and Vauquelin was only a mixture of uric
acid 'and sal-ammoniac. It is remarkable that, as far as my ob-
servations go, and I have examined the Hunterian collection of
calculi with considerable attention, it contains no calculus con-
sisting of urate of ammonia. But in the collection of the late
* Fourcroy's papers appeared in various volumes of the Annales de Chimie,
and in his Systeme des connoissances Chimiques.
t Phil. Trans. 1808, p. 223.
556 MORBID CONCRETIONS.
Dr George Monteath of Glasgow, which I examined particular-
ly, there were no fewer than six calculi composed either of urate
of ammonia, or of a mixture of uric acid and urate of ammonia.
These calculi were all extracted from young children. They
were small ; but had been a source of such uneasiness while in
the bladder, that the noise produced by opening or shutting a
door was apt to throw the child into convulsions.
In 1810,* Dr Wollaston discovered a new calculus, to which
he gave the name of cystic oxide. It was subjected to an ulti-
mate analysis by Dr Prout.
Proust stated that in some urinary calculi which he examined,
he found a quantity of carbonate of lime. This statement was
at first called in question, because Fourcroy and Vauquelin found
no such substance in the numerous calculi which they examined.
But it has been confirmed by subsequent researches. In Dr
George Monteath's collection, there was a calculus extracted from
a Highlander of 26 years of age. It was white, but not friable ;
nor did it stain the fingers. It was composed of about one part
of carbonate of lime and two parts of phosphate of lime ; and con-
tained, besides, crystals of ammonia-phosphate of magnesia.
In 1817, Dr Marcet published his Essay on the Chemical
History and Medical Treatment of Calculous Disorders. In this
work he gave an account of two new species of urinary calculi.
The first of these he called from its colour xanthic oxide.\ It
was subjected to a chemical analysis by Wohler and Liebig, who
showed that it differed from uric acid by containing two atoms
less of oxygen. The second calculus was composed entirely of
animal matter, possessing the characters of fibrin. Marcet gave
it the name oijibrinous calculus. J
Berzelius informs us that Lindbergson analyzed a urinary
calculus composed of urate of soda and carbonate of magnesia.§
It was therefore analogous to the gouty concretions analyzed by
Dr Wollaston.
Urinary calculi are most commonly ellipsoidal or egg-shaped.
They vary very much in size ; sometimes being not larger than
the head of a pin, and sometimes almost as large as a moderate
sized fist. I have seen one which was extracted after death from
* Phil. Trans. 1810, p. 223. f Essay, p. 95. \ Ibid. p. 101.
§ Traite de Chimie, vii. 413.
URINARY CALCULI. 557
an alderman of Dublin, and which almost completely filled the
bladder, that weighed several pounds.* The surface is sometimes
smooth and polished and sometimes rough, being covered with
numerous tubercles. The colour is sometimes brown, sometimes
white, and in the mulberry calculi almost black. Sometimes they
are studded with crystals of ammonia-phosphate of magnesia.
The specific gravity, according to Fourcroy, varies from 1'213
to 1-976.|
In general, when a calculus is sawn in two, we perceive that
it is composed of a number of concentric layers, covering a nu-
cleus. These layers (together with the nucleus) are sometimes
all composed of the same matter ; but more frequently the nu-
cleus consists of a substance quite different from the concentric
layers that cover it. Uric acid and oxalurate of lime are very
common nuclei. The concentric layers are sometimes composed
of the same materials ; but frequently also of different materials.
Thus they may consist of uric acid or phosphate of lime, or triple
phosphate, or of two or more of these intermixed.
The urinary calculi hitherto observed may be conveniently
arranged under the following genera :
1. Uric acid calculi. — Their most common colour is brown,
differing somewhat in the depth of shade. But this is not always
the case, for I have in my possession several small uric acid cal-
culi passed per urethram, almost as white as chalk. The surface
is sometimes smooth and polished, but not unfrequently tubercu-
lar. The specific gravity varies from 1*5 to 1786. But some-
times it is as low as 1-276. It is usually composed of concentric
laminae, differing in thickness and exactly resembling each other.
Each lamina is composed of fibres, (or small crystals,) so placed
as to be perpendicular to the central point of the calculus.
Judging from the collections of calculi which I have seen,
(amounting in all to not fewer than 1000,) this is by far the most
common of all the urinary calculi.
Uric acid calculi are very sparingly soluble in water ; requir-
ing at least ten thousand times their weight of that liquid. But
they dissolve readily in caustic potash or soda ley, especially
» Sir James Earl describes a stone taken out of the bladder after death that
must have been larger than this. It filled the bladder, and weighed 3 Ibs. 4 oz.
troy. It consisted of a congeries of calculi united together. It was composed
chiefly of triple phosphate. See Phil. Trans. 1809, p. 303.
f Systeme, x. 213.
55S MORBID CONCRETIONS.
when assisted by heat, and the uric acid is precipitated from the
solution by all acids, even by the acetic.
2. Urate of ammonia calculi. — These calculi, so far as I have
seen them, are all small. They are whitish or clay-coloured,
and composed of concentric coats. They have usually a uric
acid neucleus, and probably contain uric acid mixed with the
urate of ammonia. According to Fourcroy and Vauquelin, their
specific gravity varies from 1-228 to 1-720. They are obviously
rare ; as there is not a single specimen in the Hunterian collec-
tion, consisting of several hundred calculi. It was this circum-
stance, probably, that led Mr Brande to conclude that no calculi
composed of urate of ammonia exist.
Laugier, in 1824, analyzed a calculus taken out of the blad-
der after death. It was brown, soft, and friable, and could only
be extracted in fragments. Laugier found its constituents to be,
Uric acid, . . 10
Urate of ammonia, . . 40
Phosphate of ammonia, . 5
Oxalate of lime, . .15
Animal matter, . . 20
Moisture and loss, . .10
100*
Boutron-Charlard also found urate of ammonia in a urinary
calculus, f
3. Phosphate of lime calculi. — This calculus, first determined
and described by Dr Wollaston, is much less frequent than uric
acid calculi. The colour is usually a pale brown, and the sur-
face is quite smooth and polished. It is composed of concentric
laminae, in general adhering so slightly to each other as to se-
parate with ease into concentric crusts. The surface of each of
which, like that of the outermost, is quite smooth. The lamina? are
sometimes striated in a direction perpendicular to the surface.
When this calculus is ignited it becomes black, in consequence
of the charring of the animal matter which it contains, but it
soon burns white, and remains unaltered before the blowpipe,
unless a very high temperature be applied, when it may be fused.
It is more easily fusible than the earth of bones, because it con-
tains little or no carbonate of lime. When in powder it dissolves
readily in nitric or muriatic acid.
* Jour, de Pharmacie, x. 258. f Ibid. xxii. 556.
URINARY CALCULI. 559
This calculus is rare, only about a dozen of such occur in the
Hunterian collection.
4. Ammonia-phosphate of magnesia calculi. — Strictly speaking,
this does not constitute a peculiar species, as the double phosphate
always contains a considerable mixture of phosphate of lime ; at
least, if any exist composed of the double phosphate of magnesia
and ammonia alone, I have never happened to see them. These
calculi are yellowish-white, and have usually a tuberculated sur-
face. It is not uncommon to meet with calculi containing crys-
tals of the double phosphate. When these crystals are exposed
to the action of the blowpipe ammonia is disengaged, and biphos-
phate of magnesia remains, which undergoes an imperfect fusion.
5. Fusible calculi. — These calculi are composed of a mixture
of double phosphate and phosphate of lime. They are more
abundant than any other species, except the uric acid calculi.
They are whiter and more friable than any other species, Some-
times they resemble a mass of chalk, and leave a white dust upon
the fingers. They easily separate into laminae, the interstices of
which are often studded with crystals of the double phosphate.
But this laminated structure is not always observable. They
often acquire a very large size, sometimes nearly filling the whole
cavity of the bladder. When these calculi are urged by the
blowpipe they readily melt into a vitreous globule ; in conse-
quence of the mutual action of the biphosphate of magnesia and
phosphate of lime on each other.
When this calculus is pulverized and treated with acetic
acid, the ammonia-phosphate of magnesia is dissolved, and the
phosphate of lime remains nearly pure ; muriatic acid being
poured upon this residue, dissolves the phosphate of lime, and
usually leaves a quantity of uric acid, which not uncommonly
constitutes the nucleus of the calculus. The proportions of these
constituents, and with them the appearance of the calculus, varies
very much. When the calculus is large the outermost crust not
unfrequently contains a greater proportion of ammonia-phosphate
of magnesia than the internal parts. It is not uncommon to find
a nucleus of uric acid or oxalate of lime covered by a crust of
phosphate of lime, and that again by a crust of fusible calculus.
6. Carbonate of lime calculi. — These calculi are common in
the inferior animals, but very rare in man. It has been already
stated that human calculi containing carbonate of lime were first
560
MORBID CONCRETIONS.
pointed out by Proust. I have only met with one such calculus.
It was in the collection of the late Dr George Monteath, and had
been extracted from Hugh M'Lean from Cowal in Argyleshire,
a young man of twenty-six years of age. The calculus was not
large. It was white, but not friable, nor did it stain the fingers.
Its nucleus was crystalline, and composed almost entirely of am-
monia-phosphate of magnesia. The calculus itself, if we do not
reckon the animal matter, which was but small, consisted of one
part carbonate and two parts phosphate of lime. Bergman
also analyzed a calculus consisting chiefly of carbonate of lime.
It was of a dirty-white colour, or in some places yellow. It
readily separated into small concretions about the size of a pin-
head, which had a crystalline structure. They were soft. This
calculus consisted chiefly of carbonate of lime with an animal mat-
ter, which cemented the particles together. It contained no uric
acid, nor phosphoric acid, nor oxalic acid ; nor indeed could any
other acid be detected except carbonic.* Marchand found two
carbonate of lime calculi in the Berlin Museum. These he sub-
jected to analysis, and found them composed of
Carbonate of lime, utivu- 96 '50
Phosphate of lime, Jw,\> 2-05
Oxide of iron, .'// 0*05
Animal matter, rlvn 1*40
100-OOf
7. Mulberry calculi. — This calculus, which is not unfrequent,
is usually hard, of a dark dirty-greenish or brownish colour, and
with a tuberculated surface, in consequence of which it got the
name of mulberry calculus. Dr Wollaston first subj ected this kind
of calculus to examination, and extracted from it oxalic acid and
lime. Hence he concluded that it consisted of oxalate of lime
mixed with some uric acid and phosphate of lime. But there
can scarcely be a doubt that the true constituent is oxalurate of
lime,
Wohler and Liebig have shown that oxaluric acid is a com-
pound of
2 atoms oxalic acid, . C4 O6
1 atom urea, C2 H4 Az2 O2
C6 H4 Az2 O8
* Poggendorfs Annalen, xix 556- f Ann. der Pharm. xxxii. 323-
URINARY CALCULI. 561
When the solution of this acid is concentrated it deposites crys-
tals of oxalate of urea, and then of pure oxalic acid. Hence at
the time that Dr Wollaston made his experiments (1797), it was
impossible for him to have drawn any other conclusion than that
the acid constituent of the calculus was oxalic.
Calculi occur, which from their appearance have been called
hemp-seed calculi. They are alwsfys small, pale-coloured, and
remarkably smooth on the surface. Dr Wollaston examined
them, and found them also to consist of oxalate of lime. It would
be an object of some consequence to ascertain by a chemical an-
alysis whether the acid which they contain be oxalic or oxaluric.
These hemp-seed calculi must be very rare. I have only seen
one specimen in all the numerous collections of calculi which I
have examined.
Dr Marcet met with three different specimens of mulberry
calculi, passed per urethram by three different persons, and hav-
ing each a distinct crystalline texture. The shape of the crys-
tal was a very flat octahedron.*
6. Urate of soda calculi. — Dr Wollaston first showed that the
chalk stones which form in the joints of gouty patients consist
chiefly of urate of soda. Berzelius informs us that M. Lind-
bergson analyzed a urinary calculus which he found composed
of urate of soda and carbonate of magnesia. I met with a par-
cel of very small calculi in the collection of Dr George Mon-
teath, which were coated on the surface with urate of soda. They
were obtained from a man of 60 years of age, who laboured un-
der a diseased prostate gland. These calculi were 40 in num-
ber, about the size of a pea, some cylindrical and others approach-
ing to the cubic shape. Within they were yellow, but the ex-
ternal surface was white. The yellow portion was uric acid.
From the white surface I extracted uric acid and soda.
There was in the same collection another calculus extracted
after death. It consisted of a mulberry nucleus, covered by a
pretty thick coat of uric acid. The surface was white, and had
exactly the appearance of the surface of the small calculi just
mentioned'. Hence I considered it probable that it consisted al-
so of urate of soda, but I had not an opportunity of examining it.
9. Cystic oxide calculi. — This rare calculus, the substance con-
stituting which has already been described under the name of
* Marcet's Essay, p. 78.
N n
MORBID CONCRETIONS.
cystin* was first described and examined by Dr Wollaston.f
Calculi composed of it have a pale yellow colour, are translucent,
and appear irregularly crystallized. It was analyzed by Dr
Prout, and found composed of C12 H12 Az2 O16. It is, therefore,
probably related to oxaluric acid. Being, in fact, two atoms of
oxaluric acid -f- eight atoms water + one atom azote.
Stromeyer found cystic oxide in the gravel passed by a pa-
tient. The urine of this patient contained a good deal of cystic
oxide, but hardly any uric acid ; and the urea was not in its na-
tural state.J
10. Xanthic oxide calculi. — Only two specimens of this very
rare calculus have been hitherto observed. Dr Marcet first de-
scribed it from a specimen from Drs Babbington and Wdhler,
and Liebig analyzed it from a much larger calculus extracted
from a patient by M. Langenbeck, and still preserved in Lagen-
beck's collection. They found its constituents C10 H4 Az4 O6.
Now uric acid is C10 H4 Az4 O8. It differs, therefore, from the
xanthic oxide of Marcet, by containing two atoms more oxygen.
Hence the reason why Wohler and Liebig have given it the
name of uric oxide. It is even much rarer than cystic oxide ;
since only two calculi composed of xanthic oxide have been
hitherto discovered.
11. Fibrinous calculi. — Only a single calculus of this kind has
been hitherto met with. It was about the size of a pea, and was
given by Sir Astley Cooper to Dr Marcet.
It had a yellowish-brown colour, somewhat resembling bees'-
wax. Its hardness was also nearly that of bees'-wax. Its surface
was uneven, but not rough to the touch ; its texture rather fibrous,
and the fibres apparently radiating from the centre. It was some-
what elastic. It burnt with flame, emitting an animal smell, which
did not resemble that of uric acid, cystic, or uric oxide calculus.
It was insoluble in water and in muriatic acid, but it formed a
soapy solution with caustic potash, from which it was precipitated
by muriatic acid. Nitric acid dissolved it, though not very rea-
dily, and the solution when evaporated to dryness did not leave
a red or yellow stain. When boiled in very dilute nitric acid,
it swelled to a great size, and was at last dissolved. The solu-
* See page 105. f Phil. Trans. 1810, p. 223.
| Ann de China, et de Phys. xxvii. 221.
URINARY CALCULI. 563
tion was precipitated yellow by prussiate of potash.* The gen*
tleman who passed this calculus was from fifty to fifty-five years
of age. He had been labouring under symptoms of urinary cal-
culi for two years, recurring in the form of severe paroxysms.
He never had any pain in the kidneys or ureters, but during the
paroxysms there was great pain about the neck of the bladder,
with bloody urine, and frequent difficulty in passing it. Under
these circumstances, he passed three fibrinous calculi at three
different times, f
12. Ferruginous calculi. — Only a single calculus of this de-
scription has been met with. It had been formed in the kidney,
and was passed by a lady in Bogota, and subjected to analysis by
M. Boussingault It weighed 17 grains, and was about the size
of a hazelnut. Its form was irregular, though in some parts it
had a lamellated structure. Its colour was not uniform, being
in some parts ochre-yellow, in others deep-brown. It had great
resemblance to bog-iron ore, and had a specific gravity of 2 '886.
Its constituents, as determined by the analysis of Boussingault,
were,
Peroxide of iron, . 38-81
Alumina, . . 23-00
Silica, . . 17-25
Lime, . . 8-02
Water, . . 10-89
98-17J
If no deception was practised, this must be allowed to be a
most extraordinary concretion from the bladder of a woman.
Such are the different species of human urinary calculi hitherto
observed and examined. It is hardly necessary to remark, that
the species of more frequent occurrence are often mixed together
in the same calculus usually in concentric coats. The most com-
mon nucleus is uric acid and oxalurate of lime. When the stone
is large, and has remained long in the bladder, the outermost
coats in general consist of fusible calculus ; for it is a remarka-
ble fact, and well deserving the attention of medical men, that
whenever the bladder becomes diseased from irritation, the quan-
tity of phosphate of lime and ammonia-phosphate of magnesia in
* Marcet's Essay, p. 101. f Ibid, p 103.
\ Jour, de Pliann. xi. 153.
564 MORBID CONCRETIONS.
the urine is increased, or at least its tendency to precipitate is
very much augmented. This is partly, no doubt, owing to the
evolution of ammonia in the urine, which almost always takes
place when the inner coat of the bladder is diseased. Calculi
composed of phosphate of lime are rare, and in general they
contain no other ingredient than phosphate of lime cemented by
animal matter, and disposed in concentric coats. In some rare
cases, the external coat, or at least part of it, is uric acid ; but an
external coat of fusible calculus or ammonia-phosphate of mag-
nesia is rare. This would indicate that the urine in which phos-
phate of lime calculi are deposited is not ammoniacal.
There can be little doubt that the nucleus of almost all the
calculi is formed in the kidney : and what is called a fit of the
gravel is the pain felt while that nucleus is passing from the
kidney through the ureter to the bladder. We must except those
cases in which any solid substance makes its way into the blad-
der ; because a urinary calculus almost always is deposited up-
on this solid matter. Thus in the Hunterian collection there is
a large fusible calculus, which has for its nucleus a piece of leaden
sound. I have seen a calculus formed upon a pin, which must
have been thrust into the bladder, (probably of a female,) through
the urethra. Dr Marcet gives an instance of a musket-ball lodg-
ed in the bladder, round which as a nucleus a urinary calculus
had concreted.
As most of the constituents of urinary calculi exist in the
urine, there is no great difficulty in conceiving how they may ori-
ginate, either in the kidney or bladder.
Uric acid being a constant constituent of urine, and being
very little soluble, we can easily see how it may be deposited
whenever the quantity of free acid, which urine contains, happens
to be augmented. If uric acid exists in urine (as Dr Prout
conjectures) in the state of urate of ammonia, that salt would
be deposited whenever it exists in greater than its usual quan-
tity in ammoniacal urine. It is very curious that this state of
the urine should be confined to children, and that the deposition
of such calculi produces so great a degree of irritation.
Phosphate of lime exists in urine though in small quantity.
It is doubtless held in solution by the acid which healthy urine
contains in excess. Hence phosphate of lime can only be depo-
sited when the urine becomes alkaline by the evolution of am-
URINARY CALCULI. 565
monia. Now it is curious, that whenever the urine becomes am-
moniacal, the quantity of phosphate of lime which it contains is
very much increased. We might, therefore, expect depositions
of phosphate of lime in alkaline urine. And I believe that this
happens in almost every case. But the deposit is usually in pow-
der, and it is evacuated along with the urine, unless a nucleus
already exist to which it can attach itself, or unless a quantity of
thick mucus sufficient to form with the powder a solid concretion
happens to be present.
Phosphate of magnesia exists in urine in very minute propor-
tion, and doubtless in the state of biphosphate. When the urine
becomes ammoniacal, this biphosphate is saturated with ammonia,
and converted into ammonia-phosphate of magnesia, which, being
quite insoluble, is of course precipitated along with the phosphate
of lime. It is probable that, when the urine becomes ammoniacal,
the quantity of biphosphate of magnesia, which it naturally con-
tains, is greatly augmented. Hence the reason of the great quanti-
ty of ammonia-phosphate of magnesia found in the fusible calculi.
It has been shown that urine in certain cases contains a con-
siderable quantity of carbonic acid. If we were to admit that
when this is the case, the urine (in certain cases at least) may
contain bicarbonate of lime, it would explain the very rare for-
mation of calculi containing carbonate of lime as one of their
constituents.
It has been shown by Wohler and Liebig that when uric acid
is treated with nitric acid, it is (under certain circumstances), con-
verted into parabanic acid, and that, when parabanic acid is
united to a base, it is converted into oxaluric acid. Now Dr
Prout informs us that he has met with nitric acid in certain cases
in human urine. We can, therefore, in some measure, account for
the formation of mulberry calculi consisting of oxalurate of lime.
The formation requires the existence of nitric acid in urine. It
is true, indeed, that Wohler and Liebig found it necessary to
employ nitric acid of a given density, to apply heat, and to dis-
solve in it solid uric acid, in order to obtain parabanic acid. But
in the living body the process is much more slow. Nor can
there be any reason to doubt that nitric acid, even in the dilute
state in which it may exist in urine, may be capable, slowly and
silently, to produce the same change on uric acid in the living
body, that concentrated nitric acid, assisted by heat, produces
upon solid uric acid.
MORBID CONCRETIONS.
As urine contains both uric acid and soda, we have no rea-
son to be surprised at occasionally finding urate of soda in uri-
nary calculi. Whenever the urine is rendered alkaline by a
long continued use of carbonate of soda, one would naturally ex-
pect that the urate of ammonia would be converted into urate of
soda, which being insoluble or nearly so, would be precipitated
in crystalline grains or in powder, and this powder, cemented by
the mucus of the inside of the bladder, might give origin to a
nucleus of urate of soda. The great rarity of such calculi
shows how seldom the urine is rendered alkaline by an excess of
soda.
Cystic oxide calculi are very rare. As this substance, so far
as^we know, does not exist in urine, we cannot so readily account
for its appearing in the urinary organs. We might indeed
easily start various hypotheses to connect cystic oxide with uric
acid, oxaluric acid, and some other substances which either exist
ready formed in the urine, or make their appearance in certain
cases. But we refrain, because such hypotheses have very little
tendency to improve our knowledge.
Uric oxide, differing from uric acid simply by containing two
atoms less oxygen, we have only to conceive the action of some
deoxygenizing principle upon uric acid in the urine, in order to
account for the appearance of these calculi. Carbon, for exam-
ple, in some state or other, might be conceived to deprive uric
acid of two atoms oxygen, and to be converted into carbonic acid,
while it left the uric acid converted into uric oxide.
Fibrinous calculi seem always to be formed in the bladder.
We cannot at present account for their origin, though it may
be connected with the presence of albumen in urine. For it
has been shown in a former part of this work that albumen and
fibrin are mere varieties of the same animal principle.
Urinary calculi from the inferior animals. — These calculi have
hitherto been imperfectly examined. Indeed, if we except those
animals which have been domesticated, few opportunities occur
for examining the calculi which may be formed in the urinary
organs of the inferior animals.
1. The Horse. — Dr Pearson analyzed several calculi from the
horse. He found them to consist of phosphate of lime, phos-
phate of ammonia, and animal matter.* But a calculus from a
* Phil. Trans. 1798, p. 15.
URINARY CALCULI. 567
horse, which was given him by Dr Baillie, and which had been
found in the kidney, had a different composition. It was of a
blackish colour, very brittle and hard, and had no smell or taste-
It was heavier than human urinary calculi. It proved on ana-
lysis to consist of carbonate of lime cemented together by animal
matter. *
Mr Brande analyzed three urinary calculi from the^horse ;
the first from the kidney, and the other two from the bladder.
He found their composition as follows :
1. .2 3.
Phosphate of lime, 76 45 60
Carbonate of lime, . 22 10 40
Ammonia-phosphate of magnesia, ... 28
Animal matter, . .... 15
98 98 lOOf
Wurzer and John had found carbonate of magnesia in small
quantity in the calculi from the horse, and this was confirmed
in 1823 by the experiments of Lassaigne.J
2. The Ox. — Fourcroy and Vauquelin seem to" have been
among the first chemists who examined the urinary calculi of the
ox. They found those which they subjected to analysis' compos-
ed chiefly of carbonate of lime. This constitution was confirm-
ed by Brande, who analyzed several calculi from the bladder of the
ox, and found them composed of carbonate of lime and animal mat-
ter^ M. Lasaigne examined several in 1823, and found that the
carbonate of lime was mixed with a little carbonate of magnesia. ||
3. The Sheep. — Mr Brande analyzed a urinary calculus of a
sheep, and found it composed of,
Phosphate of lime, . 72
Carbonate of lime, . 20
Animal matter, . 8
lOOf
In the year 1830, M. Lassaigne examined a siliceous calculus
found in the urethra of a male lamb of the Merino breed. It
was white, with a slight shade of red, very friable, and had a cy-
* Phil. Trans. 1798, p. 15. t Ibid. 1808, p. 233.
t Ann. de Chim. et de Phys. xxii. 440. § Phil. Mag. xxxii. p. 178.
|| Ann. de Chim. et de Phys. xxii. 440. \ Phil. Trans. 1808, p. 235.
568 MORBID CONCRETIONS.
lindrical shape, tapering towards the extremities. It was com-
posed of concentric coats adhering very slightly to each other.
It was composed of silica mixed with a small quantity of per-
oxide of iron and some animal matter.*
4. The Hog. — Fourcroy found the calculus from a hog, ex-
amined by him and Vauquelin, to consist almost entirely of car-
bonate of lime. And a urinary calculus from a hog analyzed
by Mr Brande, contained 90 per cent, of carbonate of lime, and
the rest was animal matter.f In the year 1811, I analyzed a
calculus from the urethra of a hog, which I got from Mr Col-
ville, surgeon in Ayton, Berwickshire. It was nearly spherical,
weighed 44*2 grains, and had a specific gravity of 1 '5 95. It was
white, had a silky lustre, and was composed of a congeries of
very small needles. It consisted entirely of phosphate of lime
and animal matter.J In 1825, a calculus from the bladder of a
hog was analyzed by M. Caventou, who found its constituents
to be,
Ammonia-phosphate of magnesia, 9 9 '5
Animal matter, . . 0-4
99-9§
In the Hunterian collection of calculi in the Glasgow Universi-
ty museum there is a small phial containing a number of dark-
coloured pearls, labelled as extracted from the bladder of a hog.
They consist of alternate layers of carbonate of lime and animal
matter.
From these facts it appears that the urinary calculi of hogs, so
far as they have been examined, consist sometimes of carbonate
of lime, sometimes of phosphate of lime, and sometimes of am-
monia-phosphate of magnesia.
5. The Dog. — Fourcroy and Vauquelin examined several cal-
culi from the bladder of the dog, and found them similar to the
human mulberry calculi. || Mr Brande in 1808 analyzed a large
calculus from the bladder of a dog twenty years of age. It
weighed sixteen ounces, was extremely hard, and of a gray co-
lour. When cut through it exhibited a nucleus about the size
of a hazel-nut, partly made up of concentric layers of phosphate
* Ann. de Chim, et de Phys. xliv. p. 420. f Phil. Trans. 1808, p. 236.
| Annals of Philosophy, ii. p. 59. § Jour, de Pharmacie, xi. p. 465.
|| Ann. de Mus. d'Hist. Nat, iv.p. 338.
4
URINARY CALCULI. 569
of lime, and partly of crystals of ammonia-phosphate of magne-
sia. The part of the stone investing this nucleus was composed of,
Phosphate of lime, . . 64
Ammonia-phosphate of magnesia, 30
_______^- Animal matter, . . 6
100
Gray-coloured sand from a dog's bladder was analyzed by the
same chemist, and found composed of,
Carbonate of lime . „ 20
Phosphate of lime, . . 80
100*
In 1825, M. Lassaigne examined a calculus from the bladder
of a dog, deposited in the collection of the Veterinary School at
Alfort. It was yellowish, semitransparent, and possessed all the
characters of cystic oxide mixed with a little phosphate of lime
and oxalate of lime. Its constituents by analysis were,
Cystic oxide, . . 97*5
Phosphate and oxalate of lime, . 2*5
lOOf
A good many years ago I received from Montreal a small par-
cel containing about a dozen of pearls, which had been extract-
ed from the bladder of a dog. The colour was rather too dark,
and the surface too cloudy to permit these pearls to be used for
ornamental purposes ; but they were much more beautiful than
the pearls in the Hunterian collection from the bladder of a hog.
In 1818, Lassaigne had analyzed a calculus from the bladder
of a dog. It was yellowish, of an irregular shape, and was about
the size of a hazel-nut. It was composed of urate of ammonia
mixed with a little phosphate of lime.J
From these different analyses there is reason to suspect that
the calculi of the dog are as much diversified in their chemical
constitution as those of man.
6. The Cat. — The only chemist who has examined the calculi
from the bladder of the cat is Vauquelin, according to whom
their constitution is similar to that of human calculi. §
* Phil. Trans. 1808, p. 235. f Ann. de Cbim. et de Phys. xxiii. p. 328.
\ Ann. de Chim. et de Phys. ix. p. 324. § Ann. de Chim, Ixxxiii. p. 146.
570 MORBID CONCRETIONS.
7. The Rabbit. — Dr Pearson was the first person who examin-
ed the urinary calculus of a rabbit. It had a dark-brown colour,
was spherical, and about the size of a small nutmeg. It was hard,
brittle, and had a specific gravity of 2. It was composed of con-
centric lamina?. He found it composed of carbonate of lime and
animal matter.* Mr Brande analyzed another urinary calculus
of the rabbit in 1808. It was of a dark gray colour, weighed
four drachms, and seemed formed of a congeries of smaller cal-
culi. Its constituents were.
Phosphate of lime, . . 39
Carbonate of lime, . . 42
Animal matter, . . . 19
lOOf
8. The Rat — Fourcroy and Vauquelin seem to be the first
chemists who examined the urinary calculi of the rat, The spe-
cimens which came under their observation were composed, they
inform us, of oxalate of lime.| I am not aware of any later
analysis of these concretions.
9. The Rhinoceros. — No calculi from the bladder of this ani-
mal have been examined. But Mr Brande informs us that the
urine of the rhinoceros when voided is very turbid ; and that
when allowed to remain at rest it deposits a very large propor-
tion of sediment, which consists of carbonate of lime with small
portions of phosphate of lime and animal matter. § It therefore
resembles the urine of the horse. From this there is reason to
conclude that the urinary calculi of the rhinoceros must in their
constitution resemble those of the horse.
CHAPTER II.
GOUTY CONCRETIONS.
CONCRETIONS occasionally make their appearance in the joints
of those persons who have long laboured under gout. From the
colour and softness of these concretions they were distinguished
* Phil. Trans. 1798, p. 15. f Ibid. 1808, p. 236.
\ Ann. de Mus. d'Hist. Nat, iv. p. 338. § Phil. Trans. 1808, p. 234.
SALIVARY CONCRETIONS. 571
by the name of chalk stones. They are usually small, though it
is stated by Severinus that they have been observed as large as
an egg. It had long been the opinion of physicians, founded up-
on an alternation observed between the paroxysms of gout and
the passage of gravel in the urine, that these concretions were si-
milar to urinary calculi. Hence, after the discovery of uric acid
by Scheele, it was usual to consider the gouty chalk stones as
concretions of that acid. They were first subjected to a chemi-
cal analysis by Dr Wollaston in 1797, who found them compos-
ed of uric acid and soda.
Gouty concretions are soft and friable. Cold water has little
effect on them, but boiling water dissolves a small portion. If
an acid be added to this solution, small crystals of uric acid are
gradually deposited on the sides of the vessel containing the so-
lution. They are completely soluble in potash when the action
of the alkaline solution is assisted by heat.
When they are treated with dilute sulphuric acid or with mu-
riatic acid, the soda is separated, but the uric acid remains, and
may be separated by the filtre. When the liquid is evaporated
it yields crystals of sulphate of soda or of common salt, accord-
ing to the nature of the acid employed. The residuum possess-
es all the characters of uric acid.
When uric acid, soda, and a little warm water are triturated
together, a mass is formed, which, after the surplus of soda is
washed off, possesses the chemical properties of gouty concre-
tions.*
CHAPTER III.
SALIVARY CONCRETIONS.
SMALL concretions occasionally occur in the salivary glands,
especially the parotid and sublingual. These calculi were first
subjected to a chemical examination by Dr Wollaston, who
found them composed of phosphate of lime, associated with a
membranous substance. Fourcroy's analysis gave the same re-
sult. A small salivary concretion which I examined was com-
posed of phosphate of lime united to a membranous substance,
* Wollaston, Phil. Trans. 1797, p, 386.
•572 MORBID CONCRETIONS.
which retained the shape of the concretion after the solution of
the phosphate of lime. In a salivary concretion weighing one and
a-half grain, examined by Dr Bostock, the whole consisted of phos-
phate of lime, except a few films of matter, which was consider-
ed as coagulated albumen.* In 1827, a salivary concretion was
subjected to a chemical analysis by M. Lecanu.f It weighed
7 grains, had an ovoid shape, was slightly wrinkled on the sur-
face, and was composed of two distinct concentric laminae, the
innermost of which was hard, compact, and gray, while the outer-
most was friable and perfectly white. Its constituents were,
Phosphate of lime, . 75
Carbonate of lime, . 20
Animal matter and loss, . 5
100
Laugier had previously found some carbonate of magnesia in
a salivary concretion. But no traces of that earth could be
found in the concretion analyzed by Lecanu.
2. M. Lassaigne, in 1821, examined a salivary concretion
from a horse. :f It was an elongated ellipsoid ; and was compos-
ed of concentric coats, all seemingly of the same nature. Its
constituents were found to be,
Carbonate of lime, . 84
Phosphate of lime, . 3
Animal matter, . 9
Water, . 3
In 1828, M. Henry, Junior, analyzed a salivary concretion
taken from the anterior jaw of a horse ten years of age.§ It
consisted of four distinct portions, and was accompanied by a
number of others about the size of a pea, all near the molar
teeth and along the zigomatic apophysis. It was ovoid, formed
by the union of four distinct portions, each of which was cylin-
drical and about an inch and a-half in length. It was smooth,
whitish externally, and, as it were, polished, internally very
white, but with sanguineous spots. It was very hard and form-
* Nicholson's Jour. xiii. p. 374. f Jour, de Pharm. xiii. p. 626.
\ Ann. de. Chim. et de Phys. xix. p. 1 74. § Jour, de Pharmacie, xi. p. 465.
SALIVARY CONCRETIONS. 573
ed of concentric layers, very distinct, but having the same co-
lour. It had a nucleus, in the centre of which was a small piece
of dog-grass, round which, in all probability, the concretion had
formed. It had no taste, but a disagreeable foetid smell. Its
specific gravity was 2-209. Its constituents, according to the
analysis of M. Henry, were,
Carbonate of lime, . 85*52
Carbonate of magnesia, . 7 '5 6
Phosphate of lime, . . 4*40
Phosphate of magnesia, trace.
Common salt, . . 0*04
Organic matter and loss, . 2 '48
100-00
3. In 1825, M. Lassaigne analyzed a salivary concretion tak-
en from the duct of the parotid gland of an ass, and remarkable
for its large size.* It was as big as the fist, its shape was ovoid,
its surface smooth and white. Its hardness was about the same
as that of marble, and its weight 620 grammes, or very nearly
I Ib. 6 oz. avoirdupois. Its specific gravity was 2*302.
Its constituents, as determined by the analysis of Lassaigne,
were,
Water, . . . 3-6
Soluble principles of saliva ; soda, animal matter, soluble \ i .Q
in alcohol, chloride of calcium, sulphate of lime, &c. /
Mucus, . . . .6*4
Phosphate of lime with trace of iron, . 3*0
Carbonate of lime, . . . .85*1
99*1
From this analysis it appears that the salivary concretion of
the ass agrees very nearly with that from the horse, previously
examined by M. Lassaigne, and stated above.
4. 'To M. Lassaigne, also, we are indebted for the chemical
analysis of a salivary concretion from a cow. It was white, hard,
capable of being polished, about the size of a pigeon's egg, and
its nucleus was an oat seed. It consisted of carbonate of lime
mixed with a little phosphate of lime and some animal matter, f
5. M. Vauquelin, in 1817, analyzed a concretion found in the
* Ann. de Chim. et de Phys. xxx. p. 332, f Ibid. ix. p. 326.
574 MORBID CONCRETIONS.
maxillary gland of an elephant which died in the Museum of
Natural History in Paris.* It was white, had a lamellated tex-
ture, with some few crystals consisting of regular tetrahedrons.
Several such calculi were found in the gland ; some of them
having an oat seed as a nucleus. They consisted chiefly of car-
bonate of lime, but contained also phosphate of lime and some
animal matter, which performed the part of a cement.
CHAPTER IV.
BILIARY CONCRETIONS.
HARD bodies sometimes form in the gall-bladder, and in their
passage through the hepatic duct, being too large for the capacity
of that canal, stop up the passage altogether. These concretions
got the name of biliary calculi or gall-stones. They had drawn
the particular attention of anatomists, and in 1795 Soemmering
published an excellent monograph on the subject, f Poulletier
de la Salle discovered the existence of cholesterin in human bi-
liary calculi, and in 1785 Fourcroy examined a great number,
in order to determine whether they were all of the same nature,
or whether, like urinary calculi, they were not occasionally com-
posed of different constituents. The investigation was resumed
by Thenard in 1806, while occupied with the analysis of bile.
He examined gall-stones from oxen and from man.J Several
gall-stones were analyzed by John in 1811, by Vogel in 1820,
by Lassaigne in 1826, by Joyeux in 1827, and by Bally and
Henry, Junior, in 1830.
Biliary calculi, as far as they have been examined, may be ar-
ranged under the four different classes.
1. The first kind have a white colour, a lamellated structure,
and a brilliant crystalline appearance. They are composed of
cholesterin. They are generally ovoid, and of the size of a spar-
row's egg. Such specimens as I have seen had a yellowish sur-
face, but internally were white. In general only one is found
in the gall-bladder at the same time ; though to this rule seve-
ral exceptions exist.
* Jour, de Pharm. iii. p. 208.
•j- De concrementis biliariis corporis hvmani. $ Mem. d'Arcueil, i. p. 59.
BILIARY CONCRETIONS. 575
2. The second kind are polygonal, because a number of them
exist in the gall-bladder at the same time, which causes them to
affect each others shape. Externally they have a covering com-
posed of thin concentric layers ; within, a matter either crystal-
lized, or having the appearance of coagulated honey. They
consist of cholesterin mixed with some choleic acid, probably a
little modified in its nature. They vary considerably in their
specific gravity : one examined by Br Bostock had a specific gra-
vity of 0-900* The mean specific gravity of six which I ana-
lyzed was 1-061 ; and they all sunk in water.
These calculi, in their composition, differ but little from the
last species, since they consist almost entirely of cholesterin. In
six gall-stones which I analyzed, this matter amounted to at
least ]§ths of the whole. The residue was a reddish-brown sub-
stance insoluble in alcohol. Nitric acid dissolved it readily, and
formed a pink-coloured liquid, from which ammonia threw down
no precipitate. Pure potash ley dissolved most of it readily when
assisted by heat. From the solution, muriatic acid threw down
a dark-green matter, which had a bitter taste, dissolved in alco-
hol, melted when heated, and exhibited most of the properties of
choleic acid, The residue, insoluble in potash, was in grey
flakes, and resembled albumen in such of its properties as could
be traced. But as it never exceeded Jth of a grain, it was not
possible to ascertain its nature with precision.
3. The third kind have a brown colour, and an irregular shape.
They are composed of inspissated bile. They are much more
common in the gall-bladders of the inferior animals than in that
of man.
4. The fourth kind comprehends those gall-stones which do
not flame, but gradually waste away at a red heat. Very little
is accurately known respecting this kind of calculus. Dr Saun-
ders tells us that he has met with some gall-stones insoluble both
in alcohol and oil of turpentine ; some of which do not flame, but
become red, and consume to an ash like a charcoal.f Haller
quotes several examples of similar calculi. :f Probably they do
not differ from the third kind. Two calculi of this kind, very
different in their composition, described and analyzed by Orfila
and Bally, and Henry, Junior, will be noticed below.
In 1820, M. Vogel examined a human biliary calculus of un-
* Nicholson's Jour. iv. p. 136. f On the Liver, p. 112.
f Physiol. vi. p. 567.
576 MORBID CONCRETIONS.
common size, passed by stool. It weighed 147*66 grains, and
was as big as a nut. It was soft, had a greasy feel, and gave a
yellow powder. Its specific gravity was O912. It had no sen-
sible nucleus, and internally consisted of crystalline laminae, hav-
ing a yellow colour. It consisted chiefly of cholesterin ; but con-
tained a little yellowish -brown matter, which became green when
treated with muriatic acid.*
In 1827, M. Joyeux analyzed two human biliary calculi also
emitted by stool. The first was spherical and of the size of a
nut. It was lighter than water, and had no sensible smell. It
burnt with a lively flame. Its surface was sprinkled with white
spots, which, when viewed under a glass, had a soapy appearance.
This calculus consisted of two distinct concentric layers : the ex-
ternal had a brown colour, and was about a line thick, and was
composed of crystalline plates. The second layer was two lines
thick, had a deep-brown colour, and its crystalline texture was
less apparent. In the centre was a nucleus of six lines in dia-
meter. It was lighter coloured than the concentric coats, and
was composed of white shining plates. It was composed of,
Cholesterin, , 80
Yellow matter of bile, . 8
Carbonate of lime, . 6
Sulphate of Soda, ~\
Oxide of iron, » 6
Bile, . )
100
The concentric layers were composed of,
Cholesterin, . 76
Yellow matter, . 20
Bile, . ' 1 4
Sulphate of soda and loss, /
100
The nucleus was composed of,
Cholesterin, . 84
Yellow matter, . 12
Bile, . • I 4
Sulphate of soda and loss, /
lOOf
* Jour, de Pharm. vi. 215. f Ibid. xiii. 550.
BILIARY CONCRETIONS. 577
The second calculus had the size of a pigeon's egg. It weighed
92 '6 grains, and was lighter than water. It was covered by a
brown envelope, which broke by the smallest concussion. It was
formed of various concentric layers which had a greenish-yellow
colour, and which covered a nucleus of inspissated bile. Its con-
stituents were,
Cholesterin, 4
Yellow matter of bile, . 70
Choleic acid, . 6
Bile, ... 8
Green resin, . 5
Phosphate of lime and magnesia, 3
Oxide of iron and loss, . 4
100*
This calculus belonged obviously to the third class of gall-
stones.
In 1830, MM. Bally and Henry, Junior, analyzed a gall-stone
of quite a different nature from the preceding, and seemingly
belonging to the fourth set of biliary calculi first noticed by Dr
Saunders. It was found in the gall-bladder of a patient who
died in the Hotel -Dieu of Paris. It was of the size of a hazel-
nut, had an ovoid shape, a white colour, and a soft consistence.
Its granular texture exhibited two or three points as if petrified,
which, when viewed under the microscope, exhibited a distinct
crystallization. It was destitute of smell, and heavier than
water. When heated, it was charred without flame, and gra-
dually consumed, leaving a residue of carbonate and phosphate
of lime. Its constituents were.
Mucus or albumen, ... 10*81
Carbonate of lime, . . . 72-70
Carbonate of magnesia, trace.
Phosphate of lime, . . 13 '51
Oxide of iron, fat, and colouring matter, . 2-98
1 00-00 f
Another biliary calculus belonging to the fourth kind, but
very different in its constitution, had been described by Orfila in
* Jour, de Pharmacie, xiii. 550. t Ibid- xvi- 196<
00
578 MORBID CONCRETIONS.
1812.* It was of the size of a nutmeg. It was deep-green, and
its surface was smooth and shining. It burnt away without flam-
ing, giving out a smell like that of horn. It gave a yellow colour
to water, was partly soluble in alcohol, and partly in caustic po-
tash. The portion dissolved by water was picromel, that dissolv-
ed by alcohol was green matter of bile, and that dissolved by
caustic potash was the yellow matter of bile.
The experiments hitherto made upon the gall-stones of the
inferior animals are not numerous. Those of oxen, according to
Thenard, are always yellow, and consist of the yellow matter of
bile, mixed with minute traces of bile, which may be separated
by water. When thus washed, they are tasteless, and insoluble
in water and alcohol. They are used by painters, though the
colour is not permanent but soon changes into brown, f
In 1826, M. Lassaigne gave an account of a gall-stone ex-
tracted from a sow.} It was composed of,
Cholesterin, . . . . 6-
White resin, r:.i*. . • 4:'«; 44-95
Bile, . . ,,*'. ;^.; 3-60
Animal matter and green resin altered, 45-45
100-00
This constitutes the only example hitherto discovered of a gall-
stone of an inferior animal containing cholesterin.
CHAPTER V.
OF OSSIFICATIONS.
THE concretions which make their appearance in the solids of
the animal body may be comprehended under this name, because
they have all a close resemblance to bone, being composed of
similar constituents. The following are the most remarkable of
these concretions.
1. Pineal concretions. — It is well-known to anatomists that
small concretions like sand are often found lodged in that part
of the brain called the pineal gland. It was suspected from ana-
* Ann. dc Chim. Ixxxiv. 34. f Mem. d'Arcueil, i. 59.
| Ann. de Chim. et de Phys. xxxi. 220.
4
OSSIFICATIONS. 579
logy, that they consisted chiefly of phosphate of lime, and Dr
Wollaston proved the truth of this opinion by a chemical analy-
sis in 1797.* He dissolved some of the sand in nitric acid, and
evaporated the solution. Small needleform crystals of phosphate
of lime made their appearance.
M. Lassaigne analyzed a concretion from the brain of a horse,
It was white, slightly soft, and of the size of a nut. Boiling al-
cohol extracted from it a little cholesterin. The insoluble por-
tion, constituting the greatest portion of the concretion, consist-
ed of albumen and phosphate of lime. •(•
2. Pulmonary concretions. — It is well known that concretions
are occasionally coughed up from the lungs. They are usually
enveloped in mucus, and sometimes accompanied by blood, and
sometimes not. They may appear without any consumptive
tendency. An instance of this is given by Dr Prout. J I ex-
amined several of these concretions coughed up by a consump-
tive person, and found them composed of phosphate of lime united
to a thick membranous substance, which retained the form of the
concretion. The same result had been obtained long before by
Fourcroy.§ Dr Henry examined several, and found their con-
stitution the same as I had done. Mr Crampton examined one
which he assures us was composed of,
Carbonate of lime, . 82
Animal matter and water, 18
100 1|
One of these concretions examined by Dr Prout consisted chiefly
of phosphate of lime, with some carbonate of lime, and an animal
matter which retained the size and shape of the concretion after
the earthy matter has been removed by an acid.lf
These concretions, so far as I have seen them, are all small ;
sometimes not larger than a pin-head, and hardly ever reaching
the size of a pea. They must be deposited in the bronchia? or
in the. air-cells of the lungs.
A concretion examined by Lassaigne, and found in the me-
sentery of a bull attacked with phthisis, consisted of phosphate
of lime mixed with a little carbonate. **
* Phil. Trans. 1797, p. 386. t Ann. de Chim. etde Phys. ix. 327.
J Annals of Philosophy, xiv. 232. § Ann. de Chim. xvi. 91.
H Phil. Mag. xiii. 287. f Annals of Philosophy, xiv. 233.
** Ann de Chim. et de Phys. ix. 328.
580 MORBID CONCRETIONS.
Lassaigne examined some pulmonary concretions taken from
the lungs of a cow labouring under Phthisis pulmonalis. They
had the form of small white grains, very hard, and united toge-
ther by a mucous membrane. They consisted of phosphate of
lime, mixed with a little carbonate, and deposited in the mem-
brane.*
3. Hepatic concretions. — The liver also is sometimes full of si-
milar bodies. The shape of the hepatic concretions, as far as
my observations go, is more irregular, and I have seen them of
greater size than the pulmonary concretions. By my analysis,
they are composed of phosphate of lime and a tough animal mem-
branous matter*.
4. Concretions in the prostate. — From the experiments of Dr
Wollaston we learn that the concretions which sometimes form
in the prostate gland have phosphate of lime for their basis.
5. Concretions in the lachrymal sack. — According to Fourcroy
these concretions, which are very rare, consist of phosphate of
lime cemented by a gelatinous matter.f
CHAPTER VI.
6F INTESTINAL CONCRETIONS.
CONCRETIONS of very considerable size are occasionally found
lodged in the stomach and intestines ; seldom indeed in the hu-
man body ; but more frequently in some of the inferior animals.
Some of these bodies have acquired great celebrity under the
name of bezoars. It will be proper to state, in the first place, the
facts ascertained respecting concretions found in the human in-
testines.
Dr Monro secundus, while Professor of Anatomy in the Uni-
versity of Edinburgh, made a pretty large collection of intestinal
human calculi, which are still preserved in the Museum of the
Anatomy Class. There are a few similar ones among the collec-
tion of calculi in the Hunterian Museum of Glasgow, and Dr
Marcet informs us that Dr Bostock showed him a similar con-
* Ann. de Chim. et de Phys. ix. 328.
f Mem. de Hnstitut. T. iv. as quoted by John, Tabellen des Thierreichs, p. 46.
INTESTINAL CONCRETIONS. 581
cretion voided by a labouring man in Lancashire.* These con-
cretions on the outside are covered with a thin, whitish, smooth,
earthy crust, but when cut open they exhibit a velvety, conir-
pact, brownish surface, alternating with concentric lamina of the
white earthy substance. The white laminae consist of a mixture
of phosphate of lime and ammonia -phosphate of magnesia. The
velvety substance resists the action of chemical reagents, and
burns with the smell of straw. Dr Wollaston, by a microscopic
examination of it, found that it consisted of the minute needles
or beards which are seen constituting a small brush upon the oat
seed when deprived of its husk. It is obvious from this that
these concretions can only be formed in the intestines of those
persons who use oatmeal as an article of food. Dr Monro used
to state in his lectures that when these concretions reached a cer-
tain size they blocked up the intestines and proved fatal.
In the London and Edinburgh Journal of Medical Science for
September 1841, there is a very interesting case of a man aged
41, who passed fourteen large intestinal concretions similar to
those in Dr Monro's collection, together with an excellent and
instructive analysis of them by Dr Douglas Maclagan of Edin-
burgh.
In 1829, M. Colombot, a physician at Chaumont, sent to the
Academy of Medicine of Paris, an account of several intestinal
calculi voided by stool and of a peculiar kind. M. Caventou re-
ceived from M. Bourdois other intestinal calculi of the same
kind, and subjected them to a chemical examination. When
voided they were light, greenish, and translucent, without any
regular shape but of a considerable size. When kept for a fort-
night in a box they became opaque, grayish white, and exhaled
the smell of rancid butter ; they reddened tincture of litmus. Hot
alcohol dissolved them immediately but left empty vesicles, in
which the matter dissolved had been contained. The portion dis-
solved possessed the characters of stearin,f Lassaigne had long-
before 'examined intestinal concretions containing a great quan-
tity of stearin ; but they differed from those examined by Caven-
tou in wanting the membranous cyst in which the stearin was
confined.}
Fourcroy and Vauquelin analyzed a great number of intesti-
* Marcel's Essay, p. 129. f Jour, dc Pharm. xv. 73.
£ Ibid. p. 184.
MORBID CONCRETIONS.
nal concretions or bezoars, as they have been termed. * They
have divided them into the seven following species, which they
have named from the constituents of the respective concretions :
1. Superphosphate of lime. 4. Biliary.
2. Phosphate of magnesia. 5. Resinous,
3. Ammonia-phosphate of 6. Fungous,
magnesia. 7. Hairy.
1. Superphosphate of lime. — The intestinal concretions belong-
ing to this species are composed of concentric layers, easily se-
parable from each other and very brittle. They redden vegeta-
ble blues, and are partially soluble in water. The layers are
unequally thick, and differ in their colour, f They were found
in the intestines of different mammalia.
2. Phosphate of magnesia. — These concretions are uncommon.
They are semitransparent, and have usually a yellowish colour.
Their specific gravity is 2-160. They are formed of layers less
numerous, and not so easily separated as those of the preceding
species. J
3. Phosphate of ammonia and magnesia. — This species is the
most common of the intestinal concretions. Its colour is gray
or brown, and it is composed of crystals diverging like rays from
a centre. It has some resemblance to calcareous spar. It con-
tains abundance of animal matter. This species occurs frequent-
ly in the intestines of herbivorous animals, as the horse, the ele-
phant, &c.
4. Biliary. — This is a species of concretion found frequently
in the intestines of oxen, and likewise in their gall-bladder, and
employed by painters as an orange-yellow pigment. Its colour
is reddish-brown. It is not composed of layers, but is merely a
coagulated mass, and appears to be but little different from the
matter of bile. When heated it melts. It dissolves readily in
alkalies. Alcohol dissolves it partially, and acquires a very bit-
ter taste. §
This species has been already noticed while treating of biliary
calculi, to which in reality it belongs.
5. Resinous. — To this species belong many of the oriental be-
zoars, formerly so celebrated, obtained from the intestines of
animals with which we are unacquainted. They are fusible and
* Ann. de Mus. d'Hist. Nat. iv. 331. f Ibid, i. 102, and iv. 331.
| Ibid. iv. 332. § Ibid. iv. 333.
INTESTINAL CONCRETIONS. 583
combustible, composed of concentric layers, smooth, soft, and
finely polisbed. Fourcroy and Vauquelin have distinguished
two varieties ; the first o£ a pale-green colour, a slightly bitter
taste, almost completely volatile ; giving by heat a solid tenaci-
ous matter, soluble in alcohol, and separating in crystals as the
solution cools. This matter consists partly of bile, partly of re-
sin. The second variety has a brown or violet colour ; its taste
is not bitter ; it does not dissolve in alcohol, but is soluble in
alkalies. The solution becomes purple-red when allowed to dry
in the open air. When distilled it yields a yellow sublimate,
having the smell and taste of soot, and insoluble in water and al-
cohol, f
6. Fungous.— This species consists of concretions composed of
pieces of the Boletus igniarius, disposed in layers, and cemented
by an animal matter. These pieces had been doubtless swal-
lowed by the animals in whose intestines they were found. \
7. Hairy. — Balls of hair felted together, sometimes pure,
sometimes covered with animal matter, and sometimes mixed with
vegetable remains, occur very frequently in the intestines of ani-
mals. J
8. Ligniform, — This eighth species must be added in conse-
quence of the experiments of Berthollet Among the presents
sent to Bonaparte by the King of Persia were three bezoars, which
were consigned to Berthollet for analysis. They all belonged
to this species. They had an oval shape, and a very smooth sur-
face. Their colour externally was greenish-black, internally
brown. They were formed of irregular concentric layers. In
the centre of one was found a collection of straws and other ve-
getable fragments ; in that of the other, small pieces of wood
about the size of a pin. Their specific gravity was 1/463. They
were insoluble in water, alcohol, and diluted muriatic acid. Po-
tash ley dissolved them readily, and they were thrown down un-
altered by muriatic acid. When distilled they yielded the pro-
ducts of wood, and left a quantity of charcoal in the retort, which,
when incinerated, gave traces of sulphate of soda, muriate of
soda, liine, and silica. Thus it appears that they possessed all
the properties of pure woody fibre. They must have been form-
ed in the stomach of the animals, and not in the alimentary canal. §
* Ann. de Mus. d'Hist. Nat. iv. 334. f Ibid. 335. \ Ibid. 336.
§ Mem. d'Arcueil, ii. 48.
584 MORBID CONCRETIONS.
To these intestinal concretions may be added one found in a
scirrhus situated in the meso-colon (an organ connected with
the large intestines) of a mare, and examined by Lassaigne. It
was yellowish, greasy to the feel, had the odour of rancid oil,
and strongly stained blotting-paper. It was a mixture of albu-
men and a peculiar matter, consisting partly of cholesterin, and
partly of a white substance, crystallizing in needles, and redden-
ing vegetable blues. When this concretion was calcined it yield-
ed phosphate and carbonate of lime.*
In the year 1827, I received from Dr Vallance of Strathaven
a very large intestinal calculus from a horse. When taken out
it weighed above four troy pounds, or very nearly five pounds and
a-half avoirdupois. It measured 20 inches round its greatest
circumference, and 18 inches round its lesser. When cut
through the centre, it exhibited a set of concentric layers of the
husk of oats, mixed with some straws and hay. These layers
were separated from each other by thinner white layers, consist-
ing chiefly of subsesquiphosphate of lime. In the centre of the
calculus there was a little piece of hard stone, which seems to
have served as a nucleus.
This calculus had a specific gravity of 1-609. When dried
on the steam-bath, it lost 35*22 per cent, of its weight. A por-
tion thus dried being subjected to analysis was found composed
.as follows :
Lost by ignition, . 40 '7 3 f
Phosphate of lime, .. 41-01
Carbonate of lime, . 0-41
Carbonate of magnesia, . 5-28
Carbonate of potash, . 2-32
lEarthy insoluble matter, . 9*80
99-55
M. Girardin analyzed in 1840 an intestinal concretion from a
horse.:): The horse belonged to a miller, who lost five horses in
a short time, in all of which many intestinal concretions were
found. The horses were fed with bran ; and M. Lassaigne had
observed, that several asses which had been fed with bran had
* Ann. de Chim. et de Phys. ix. 329-
f This loss was occasioned by burning the oat beards and the hay and straw
visible in the calculus.
J Jour, de Pharm. xxvi. 420.
3
INTESTINAL CONCRETIONS. 585
died from intestinal concretions composed of ammonia-phosphate
of magnesia.
The calculus analyzed by Girardin was triangular with its
edges and surface smoothed ; showing that it had existed along
with other calculi in the intestines. It was of the size of a large
apple. It weighed 311 grammes. Its texture was crystalline,
its colour brown, and its specific gravity 1*741. Its constituents
were,
Water, . . . 14O
Ammonia-phosphate of magnesia, . 48 '0
Phosphate of lime, . . . 19-0
Animal matter, insoluble in acid and water, . 0-8
Matters soluble in water,* . . 6*6
Extractive soluble in alcohol, f . . 4*0
Fatty matter, . „:.• . .7-0
99-4
M. Schwerkert, apothecary in Dingelstadt, has also given an
account of an ammonia-phosphate of magnesia calculus found
after death in the caecum of a horse.:f
There are four calculi in the Hunterian collection in Glas-
gow composed of lithofellic acid. They are oval-shaped, and
composed of concentric layers. The largest is about two inches
in length and one inch in thickness, and weighs about 320 grains.
One of these calculi has for a nucleus a date-stone ; the nucleus
of another is a vegetable substance resembling matted hair.
Hence they would seem to be intestinal concretions of some in-
ferior animal, — probably bezoars.
DIVISION III.
OF THE FUNCTIONS OF ANIMALS.
THE object of the preceding part of this work has been to ex-
hibit a view of the different substances which enter into the com-
position of animals, as far as the present limited state of our
* Albuminate of soda, common salt, alkaline sulphates, salts of lime and
magnesia.
f With common salt, salts of magnesia, and fatty matter.
\ Ann. der Pharm. xxxvii. 200.
586 FUNCTIONS OF ANIMALS.
knowledge puts it in our power. But were our inquiries con-
cerning animals confined to the mere ingredients of which their
bodies are composed, even supposing the analysis as complete as
possible, our knowledge of the nature and properties of animals
would be imperfect indeed.
How are these substances arranged ? How are they produced ?
What purposes do they serve ? What are the distinguishing pro-
perties of animals, and the laws by which they are regulated.
Animals resemble vegetables in the complexness of their struc-
ture. Like them, they are machines nicely adapted for particu-
lar purposes, constituting one whole, and continually performing
an infinite number of the most delicate processes. But neither
an account of the structures of animals, nor of the properties which
distinguish them from other beings, will be expected here : these
topics belong entirely to the-anatomist and physiologist. I mean
in the present Division to take a view of those processes only that
are concerned in the production of animal substances, which alone
properly belong to Chemistry. The other functions are regu-
lated by laws of a very different nature, which have no resem-
blance or analogy to the laws of Chemistry or Mechanics.
CHAPTER I.
OF DIGESTION.
EVERY living being constitutes a complicated machine, com-
posed of a great variety of parts, all of which conspire to produce
certain ends calculated for the benefit of the whole. The waste
which is continually going on is repaired by the conversion of
the food into all the different substances which make up the whole
of the living structure. This extraordinary but necessary pro-
cess is distinguished by the name of digestion.
In man and the larger animals the food passes through a num-
ber of tubes or canals, and gradually during the course of its
progress assumes the form of blood. This blood circulates through
appropriate vessels, and supplies the waste of every organ in the
body. Bony matter for the bones, muscular matter for the
muscles, nervous matter for the brain, &c. or it passes through
certain tubes, constituting the matter of which glands are com-
posed, and during its progress it is converted into the various se-
DIGESTION. 587
cretions, useful or indispensable for the animal economy. In this
way are formed the seminal fluid of the male, the milk of the fe-
male destined for the nourishment of the offspring ; and in this
way are formed the saliva, the bile, the pancreatic juice, the mu-
cous matter which lines the cavities of the body, and all the dif-
ferent secretions so indispensable for the use of the living animal.
How these changes are induced has hitherto eluded the utmost
sagacity of physiologists. But, in man and the greater number
of animals, the agency of the nervous filaments which are spread
through all the essential organs of the body, is indispensable.
Accordingly, when these nerves are cut or diseased, the organ
which they supply ceases to perform any of its functions. Hence
in man and in most animals, we may say that the nervous ener-
gy, whatever it may be, constitutes the indispensable part of the
living structure. Yet it cannot be maintained that life cannot
exist without nerves ; for plants are undoubtedly living beings.
They require food and digest it, just as animals do ; and the di-
gested food is afterwards applied to all the purposes of secretion
and assimilation, just as in animals. Yet nothing like nervous
structure has ever been observed in vegetables ; nor is there the
least reason for supposing them supplied with nerves.
The digestion of food, or the conversion of it into blood, though
we are utterly incapable of imitating it by artificial processes,* [is
purely a chemical process. We can only expect to learn the
contrivances which nature follows in it by investigating the dif-
ferent changes which the food undergoes as it passes in succes-
sion through the different organs employed in digestion, and by
ascertaining the chemical nature of the different substances which
are employed in the successive steps by which the food is con-
verted into blood.
Let us then examine in succession the changes which the food
undergoes, and the liquids employed in producing these changes.
We must confine ourselves chiefly to the human species, though
a very great proportion of the facts which have been acquired
were obtained by experimenting upon the inferior animals, par-
ticularly dogs, whose food and whose organs of digestion bear a
close resemblance to those of the human body.
The food of man is of two kinds, partly animal and partly ve-
getable ; and the structure of his teeth shows that nature intend-
ed him to make use of both. The vegetable substances which
answer best for food are, sugar, gum, and starch. And, as has
been well observed by Dr Front, those vegetable substances are
588 FUNCTIONS OF ANIMALS.
the most nutritious which contain all the three mixed in the re-
quisite proportions. None of the three are often exhibited by
nature in a state of purity. They are extricated from various
plants by artificial processes, more or less intricate and laborious.
Pure sugar was shown by Magendie not to be capable of sup-
porting the life of dogs. He fed them upon refined sugar.
They swallowed the food with avidity, yet they became lean and
thin, and exhibited all the symptoms of animals in a state of star-
vation. After some weeks, ulcers broke out in the cornea, first
of one eye and then in the other. These ulcers went on increas-
ing till they penetrated the cornea, and the liquors of the eye
were discharged by them. The dogs expired about the 32d day
in a state of complete exhaustion.*
It would have been more satisfactory had this experiment
been made in a different manner. The dog is accustomed to
live entirely, or nearly so, on animal food. Hence the stomach
and intestines of these animal not being accustomed to vege-
table food, might not be able all at once to digest it. It is possible
that, had the change been induced sufficiently slowly, dogs might
at last be brought to live upon sugar. Yet it cannot be doubt-
ed, that had loaf bread been substituted for sugar, and that if
the dogs had been allowed to eat of it ad libitum, and at the
same time had been supplied with a sufficient quantity of water,
the change of diet, though it might not have been relished, and
though the animals might not have thriven on it, yet would not
have occasioned death. The juice of the sugar cane, in which
the sugar is mixed with mucilage and albumen, is a nutritive ar-
ticle of food. For it is said that the negroes in the West Indies
get fat from the unrestrained use of the juice during the season
in which raw sugar is manufactured.
The animal matter, which seems to constitute the most nutri-
tious article of food, is a proper mixture of gelatin, albumen, and
fibrin, together with a certain portion of fat, as they exist in the
flesh of a well-fed ox or sheep.
The use of animal food alone seems to have a tendency to
bring the body into an unhealthy state. As that dreadful dis-
ease, the sea-scurvy, is the usual consequence of it, at least when
the meat is salted, A restriction to vegetable food does not
seem by any means so injurious. Many persons who restricted
* Ann. de Chim. et de Phys. iii. 66.
DIGESTION. 589
themselves to it have enjoyed good health for years. Indeed
in some parts of the world, Hindostan for example, animal food
is abstained from on account of a religious scruple, and yet the
inhabitants enjoy health.
Wheat flour seems one of [the most nourishing articles of
vegetable food. In the northern parts of India, where the popu-
lation live upon wheat, the inhabitants are said to be a stouter
and more hardy race than those who live in the south, where
the food is rice. But perhaps other circumstances besides the
different quantity of nourishment in wheat and rice may intervene
to constitute this difference.
We have a number of interesting experiments by Sir Astley
Cooper, on the relative digestibility of various articles of food.
To understand the way in which these experiments were made,
it is necessary to state that the food in the stomach is dissolved
in the gastric juice, and that the difficulty of digestion is consi-
dered as proportional to the length of time which elapses before
the food in the stomach is dissolved. If, therefore, we put a giv-
en weight of any food into the stomach of an animal, allow it to
remain a certain time and then weigh it again, it is clear that
the food which weighs least will be the most digestible. Sir
Astley Cooper made his experiments on dogs. Given weights
of the respective articles were put into the stomach of the dog.
After a certain interval he was killed, and the proportion remain-
ing undissolved in the stomach determined. Raw food and the
lean parts only of meat were given, except when the contrary is
expressed :
Experiment 1st.
Kind of food.
Pork,
Mutton,
Button,
Beef,
Veal, •
Pork,
Pork,
Mutton,
Beef,
Veal,
Form. Quantity.
Animal kil-
Loss by di-
led after.
gestion.
Long and narrow. 100
1 hour.
10
Do. 100
Do.
9
Do. 100
Do.
4
Do. 100
Do.
0
Experiment 2d.
Long and narrow. 100
2 hours.
46
Do. Do.
Do.
34
Do. Do.
Do.
30
Do. Do.
Do.
20
Experiment 3d.
Long and narrow. 100
3 hours.
98
Do. Do.
Do.
87
Do. Do.
Do.
37
Do- Do.
Do.
46
590
FUNCTIONS OF ANIMALS.
Kind of Food.
Experiment 4th.
Form. Quantity.
Animal kil- Loss by
led after digestion.
Pork,
Long and narrow. 100
4 hours.
100
Mutton,
Do. Do.
Do.
94
Beef,
Do. Do.
Do.
75
Veal,
Do. Do.
Do.
69
Experiment 5th.
Cheese.
Square. 100
4 hours.
76
Mutton,
Do. Do.
Do.
65
Pork,
Do. Do.
Do.
36
Veal,
Do. Do.
Do.
15
Beef,
Do. Do.
Do.
11
Experiment 6th.
Beef,
Long and narrow, 100
2 hours.
0
Rabbit, -*:
Do. Do.
Do.
0
Cod fish, .
Do. Do.
Do.
74
Experiment 7th.
Cheese,
Long and narrow. 100
2 hours.
29
Fat,
Do. Do.
Do.
70
Experiment 8th.
100 beef,
.
...
100
100 potatoes,
...
...
48
Experiment 9th.
Roast veal,
Long and narrow. 100
...
7
Boiled do.
Do. Do.
...
30
Experiment I Oth.
Roast veal,
Long and narrow. 100
...
2
Boiled do.
Do. Do.
...
31
Experiment llth.
Muscle,
100
4 hours.
36
Skin,
Do.
Do.
22
Cartilage,
Do.
Do.
21
Tendon,
Do.
Do.
6
Bone,
Do.
Do.
5
Fat,
Do.
Do.
100
Experiment 12th.
Thigh-bone,
•'-.. . ... 100
3 hours.
8
Ditto,
Do.
6£ hours.
30
Scapula,
Do.
6 hours.
100*
It would appear from the experiments that pork is the most
digestible of the common meats in the stomach of the dog. In
the human stomach, when weakened, the order of digestibility
seems to be mutton, beef, veal, pork. But we must recollect that
these articles of food were given to the dog in a raw state, while
before they are introduced into the human stomach they have been
either roasted or boiled. From experiments 9 and 10, it ap-
* Dodsley's Annual Register, 1823, p. 285.
DIGESTION. 591
pears that boiled veal is more easily digested than roasted ; and
from experiment 6, that cod-fish is much more digestible than
either beef or rabbit. From experiment 5th, it appears that
cheese is more digestible than meat ; and from experiment 7th,
that fat is much more digestible than cheese. Experiment 8th
shows us that beef is more easily digested than potatoes.
Dr Stark made a great number of experiments on himself. He
lived a fortnight on bread and water ; and found that during that
time the weight of his body had diminished by 3 Ibs. He lived
a month on bread, sugar, and water, and during that interval
his body became lighter by 3J Ibs. He substituted olive oil for
the sugar ; but the change producing purging and injuring the
health, he was obliged to give it up. Milk being substituted,
for the oil was found to agree better, though he still lost weight.
Bread, water, and roasted goose seemed to agree with him per-
fectly. He tried bread, water, and boiled beef; stewed lean of
beef with gravy and water ; the same with the addition of suet ;
flour, oil of suet, water and salt ; flour, fresh butter, water and
salt ; yolk of eggs, suet, figs, and water ; flour, oil of marrow,
water, and salt ; bread with roasted fowl, infusion of tea and su-
gar ; bread, stewed lean of beef with gravy, infusion of tea with
sugar ; bread, the fat of stewed beef with jelly, water and salt ;
bread, fat of bacon ham, infusion of tea with sugar, &c. These
experiments he continued for more than half a year. The con-
sequence was the destruction o£ the tone of the stomach and a
fever which speedily carried him off. Scarcely any conclusion
can be drawn from these experiments ; except the danger of per-
sisting in an aliment which is particularly offensive to the sto-
mach ; and the necessity of varying the food if we wish to enjoy
good health.*
From the numerous experiments of Tiedemann and Gmelin, it
seems to follow that animal food is more easily digested by dogs
than vegetable food.f
Every body knows that in man and all the more perfect ani-
mals the food is introduced into the mouth, where it is commi-
nuted by the teeth, and mixed up into a kind of magma or pulp
by means of the saliva.
* The works of W. Stark, M. D. p. 89.
•f" Recherches Experimentales, Fhysiologiques, et Chimiques sur la Digestion
i. p. 178.
592 FUNCTIONS OF ANIMALS.
An account of the saliva has been given in a preceding chap-
ter of this work, to which the reader is referred for a minute de-
tail of its chemical properties.
It is a liquid nearly colourless, somewhat viscid, and usually
containing a few white flocks, which gradually sink to the bottom
when the saliva is left at rest in a vessel. It is thrown into
the. mouth from the salivary glands, when it is secreted, and in
greatest abundance during the mastication of the food. The
whole amount of it in twenty-four hours from an adult indivi-
dual is about seven ounces and a-half avoirdupois.*
Human saliva, when dried in the vacuum of an air-pump over
sulphuric acid, leaves 1*62 per cent, of solid residue. These 1-62
parts contain 0-42 1 of the white flocks which may be considered
as mucus. They contain 0-528 of a matter soluble in water, but
insoluble in alcohol of 0-863. This is the substance to which
the name of salivin has been given, and the properties of which
have been described in a former chapter of this volume. Its use
in digestion has not yet been ascertained ; but, as it possesses the
characters of a weak acid, it is highly probable that it facilitates
the conversion of the food into chyme in the stomach.
The 1-62 of insoluble residue contains also 0-444 of a matter
soluble in water ; but insoluble in alcohol of 0*800. This mat-
ter consists chiefly of chlorides of potassium and sodium : but is
not quite free from salivin. The residue of the 1'62 amounting
to 0-288 is soluble both in water and in alcohol at 0-800. It
consists chiefly of lactate of soda, and of soda combined with mu-
cus, but is not quite free from salivin.
Thus the solid contents of healthy saliva from 100 parts of
that liquid are,
Mucus, . 0-421
Salivin, v/i; 0-528
Salts, 0-732
1-681
In this analysis, which was made by Mitcherlich, there is an ex-
cess of 0-061.
The great use of the saliva is doubtless to lubricate the food,
and cause it to descend easily into the stomach ; but it is proba-
ble that the salivin which it contains contributes somewhat to the
conversion .of the food into chyme. Accordingly, it appears
* Poggendorf's Annalen, xxvii. p. 320.
DIGESTION. 5Q3
from the experiments of Eberle, Muller, and Schwann, that cer-
tain articles of food, when put into glass tubes containing saliva,
and kept at the temperature of 100°, are dissolved. This, in par-
ticular, is the case with starch, which, by digestion in saliva, is con-
verted into gum and sugar.
The food thus ground down by the teeth and moistened by the
saliva, passes along the oesophagus into the stomach, which is a
strong membranous and muscular bag, situated in the upper
part of the abdomen, immediately below the diaphragm, and ra-
ther more inclined to the left than the right side, especially when
distended with food. The innermost or villous coat is said to be
larger than the other coats, and therefore to be wrinkled into
folds ; but this is not very evident on dissection, if we except the
fold distinguished by the name of the valve of the pylorus.
In the stomach the food undergoes a farther change, being
converted into a kind of pap, called chyme. The food, after
mastication in the mouth, still retains its sensible qualities, and
may be recognized by the colour, taste, and smell which it pos-
sessed before mastication ; but when food is converted into chyme
its sensible qualities are altered. We can no longer recognize
the kind of food which has been taken into the mouth. This
change of the food into chyme is the first step in the process of
digestion — a step altogether performed by the stomach.
It seems to follow from the observations of Dr Wilson Philip
that in rabbits, which live entirely on vegetable food, those parts
only of the food are changed into chyme which come in contact
with the internal coat of the stomach. This organ, in conse-
quence of its muscular coat, appears to be in motion, similar to
the peristaltic motion of the intestines, during the whole process
of ventricular digestion. By this motion those portions of the
food which have been converted into chyme are pushed forward
towards the pyloric orifice, and new portions of the food come in
contact with the stomach to undergo a similar change.
Frdrn the experiments of Dr Stevens it is evident that in the
human stomach food may be converted into chyme without com-
ing in contact with its innermost coat* His experiments were
made upon a man who supported himself by swallowing stones
for money. He had accustomed himself to this practice from
* See his Thesis De Alimentorum concoctione, printed in Edinburgh in the
year 1777. It was inserted in the lirst of the four volumes of theses published
in Edinburgh by Elliot in 1786.
PP
594 FUNCTIONS OF ANIMALS.
the age of seven, and had continued at it for twenty yeara
His stomach was so much distended that he could swallow many
stones at once. They could not only be felt in his stomach, but
when he struck the hypogastric region of the abdomen they might
by the bystanders be heard to rattle. Dr Stevens inclosed in
silver perforated spheres 2J inches long, and 3£ inches in circum-
ference, various kinds of food. The spheres were evacuated
about twenty hours after being swallowed, and it was in Dr
Stevens's power to ascertain what change the food had undergone.
A few of the experiments will enable the reader to judge of the
results. 41 scruples of raw beef lost 1^ scruple of their weight.
The silver sphere was divided into two compartments. Into
the one was put 1 scruple 4 grains of raw beef, and into the
other 4 scruples 8 grains of boiled beef. The sphere was voided
in forty-three hours. The raw beef had lost 1 scruple 2 grains
of its weight; the boiled beef 1 scruple and 16 grains.
Silver spheres were now employed, the numerous perforations
in which were of the size of a crow quill. The following were the
experiments made :
Substances introduced. J*?** °^ti™e Result.
before voided.
Beef slightly masticatedj 38 hours. All dissolved.
Raw pork, . 45 . Ditto.
A piece of cheese, . 45 . Ditto.
Roast pheasant, . 46 . Ditto.
Salt herring, 46 . Ditto.
Raw parsnep, 48 . Ditto.
Raw potato, 48 Ditto.
Raw turnip, ; '. ''.'** 36 . Ditto.
Boiled turnip, v 36 . Ditto.
Apple, raw, ;7 ' V:> 36 . Ditto.
Do. boiled, ;'.' -.®\ 36 . Ditto.
Grains of rye, Many hours. Not altered.
wheat, V • Do. . Ditto.
barley, . Do. . Ditto.
oats, Do. . Ditto.
Peas, . . . Do. . Ditto.
Thigh-bone of sheep, . 48 . Ditto.
Wing of pheasant, . 48 J A11 ^f J^"
Living leech, . . ... . All dissolved.
Living lumbricus, ... . Ditto.
DIGESTION. 595
Dr Stevens proved likewise by his experiments that the sto-
mach of certain animals — the dog, for example, acted more
powerfully upon animal than on vegetable food. On the con-
trary, the stomach of the sheep and ox acted powerfully on ve-
getable food, while it produced no sensible alteration on animal
food. This will be evident from the following experiments :
I. The Dog.
Food inclosed Hours in the Loss of
in spherules. stomach. weight.
17 parts raw beef, 4 5 parts.
Do. raw cod, . 4 9
Do. raw potato, . 4 3
Do. raw cabbage, 4 1
Do. roast mutton, 4 6
Do. boiled turbot, 4 10
Do. parsnep, . 4 0
Do. boiled potato, 4 5
The food was inclosed in perforated ivory spheres. The ivory
was obviously corroded. This induced Dr Stevens to make the
following experiments :
17 boiled mutton, . 8 hours. All dissolved.
Do. fish, . Do. Do.
Do. potato, . Do. 11 parts.
Do. parsnep, . Do. 0
The ivory balls in which these articles had been inclosed were
dissolved and had disappeared. He then made a dog swallow
three pieces of the thigh-bone of a sheep. In seven hours,
The 1st fragment lost 7 grains of its weight.
2d ... 9
3d ... N 12
In the following experiments made on the stomach of the dog
the articles of food tried were enclosed in perforated tin-cases,
which were not in the least acted on :
Weight lost.
17 parts roast beef, . 10 hours. All dissolved.
Do. roast veal, . Do. . 10 parts.
Do. tallow, . Do. 8 do.
Do. wheat bread, Do. All dissolved.
Do. roast mutton, 7 hours. Do.
Do. roast lamb, Do. 1 0 parts.
596 FUNCTIONS OF ANIMALS.
Weight lost.
17 parts raw beef, .Do. 10 parts.
Do. roast beef, . Do. All dissolved.
Do. raw cod, . Do. 14 parts.
Do. boiled cod, . Do. All dissolved.
Do. roast beef, . . Do.
Do. roast mutton, . . Do.
Do. roast fowl, . .11 parts.
We see from these trials that in the dog's stomach old meat is
more easily digested than that of young animals, and that roast-
ed or boiled meat and fish are more easily digested than when
in a raw state.
II. The Sheep.
Raw beef, . 6 hours. Unchanged.
Raw salmon. . Do. Unchanged.
Raw radish, . ] Do. All dissolved.
Raw potato, . 1 Do. All dissolved.
When the experiments were repeated with the same articles
boiled, the result was the same.
III. The Ox.
Beef, . 10 hours. Unchanged.
Fish, . Do. Unchanged.
Hay, . Do. All dissolved.
Cabbage, -T *• Do. All dissolved.
Similar experiments were made by Reaumur and Spallanzani ;
but it is unnecessary to state them, because the results were
nearly the same.
It will now be proper to describe somewhat in detail the phe-
nomena which take place in the stomach during digestion. This
cannot be done better than by stating the observations made by
Dr Prout on the subject*
1. Digestion in the Rabbit. — A rabbit, which had been kept
from food for twelve hours, was fed upon a mixture of bran and
oats. About two hours afterwards it was killed, and examined
immediately while still warm. The stomach was moderately dis-
tended with a pulpy mass, which consisted of the food in a minute
state of division, and so intimately mixed, that the different ar-
ticles of which it was composed could be barely recognized.
The digestive process, however, did not appear to have taken
* Annals of Philosophy, (1st series), xiii. 13.
DIGESTION. 597
place equally throughout the mass, but seemed to be confined
principally to the superficies, or where it was in contact with the
stomach.* The smell of the mass was peculiar, and difficult to
describe. It might be called weak but disagreeable. On being
wrapped up in a piece of linen, and subjected to moderate pres-
sure, it yielded upwards of half a fluid ounce of an opaque, red-
dish-brown fluid, which instantly reddened litmus-paper very
strongly, though not permanently, as, upon being dried or even
oxposed to the air for a short time, the blue colour was restored.
It instantly coagulated milk and redissolved the curd, convert-
ing it into a fluid similar to itself. It was not coagulated by heat
or acids, and therefore contained no albumen. On being evapo-
rated to dryness, and incinerated, it left an alkaline chloride
with traces of an alkaline phosphate and sulphate, together with
sulphate, phosphate, and carbonate of lime.
2. Digestion in the Pigeon. — The bird was young, but fully
fledged, and had been fed about two hours before it was killed
upon a mixture of barley and peas. It was opened and examin-
ed immediately after death. In the crop was a portion of food which
was swollen and soft, but appeared to have undergone no farther
sensible change than might have been expected from mere heat
and moisture. This organ did not exhibit any evidence of the
presence of an acid. The gizzard or stomach contained corn
in various states of decomposition, the internal parts of some
of the seeds being reduced to a milky pulp, which flowed out on
their being subjected to pressure ; others were reduced to a mere
husk, while others were in various states between these two ex-
tremes. The whole contents of the stomach exhibited decidedly
acid properties. But the litmus-paper recovered its blue colour
again almost instantly after exposure to the atmosphere. They
coagulated milk, but yielded no trace of albumen.
3. Digestion in the Tench and Mackerel. — The contents of
the stomach and upper intestines of the tench were examined im-
mediately after death ; but, as the fish had been kept for some
time in an unnatural state, the phenomena were not quite satis-
factory. The contents of the stomach and upper portion of the
intestines consisted of little more than a yellowish glairy fluid,
which seemed to be bile ; and the small quantity of alimentary
* This corroborates Dr Wilson Philip's statement noticed above.
598 FUNCTIONS OF ANIMALS.
matters present appeared to be unnatural, and little capable of
being acted upon by the digestive organs. No traces of albu-
men could be found.
The mackerel examined had just come from the coast where it
had been caught the day before. The stomach was nearly filled
with a whitish grumous mass, in which the undigested bony remains
of some small fish were visible. This mass very faintly reddened
litmus, and, by the assistance of heat, coagulated milk. It un-
derwent a partial coagulation by the acetic or other acids, espe-
cially when heat was applied ; but no traces of albumen could
be perceived in it.
Physiologists seem to have been generally of opinion that the
stomach contained an uncombined acid, somehow connected with
the process of digestion, till Spallanzani concluded, from a great
number of experiments, that the gastric fluid, when in its natural
state, is neither acid nor alkaline. In the year 1823, Dr Prout
ascertained by numerous experiments that a free acid exists in
the stomach of the rabbit, the hare, the horse, the calf, and the
dog, and also in the liquid ejected from the human stomach in cases
of dyspepsia. He washed the contents of a rabbit's stomach with
distilled water, and divided the aqueous liquid into four equal
portions. The first was evaporated to dryness, and the residuum
incinerated. It was then redissolved, and the chlorine which it
contained was determined by means of nitrate of silver. The
second portion was supersaturated with potash, evaporated to dry-
ness, ignited, and its quantity of chlorine determined by nitrate
of silver. This gave the whole chlorine in the contents of the
stomach. The third portion was exactly neutralized by a solution
of potash of known strength. This gave the quantity of free
muriatic acid in the stomach. And from these data the quan-
tity of sal-ammoniac was calculated. The following table will
show the result of three experiments on the gastric juice of rab-
bits:
No. 1. No. 2. No. a
Grains. Grains. Grains.
Muriatic acid combined with ~i
fixed alkali, . /
Ditto with ammonia, . 1-56 0-76 0-40
Ditto uncombined, . 1'59 2-22 2-72
Total, 3-27 3-93 4-83
DIGESTION. 599
The following table shows the quantity of muriatic acid in
one pint of the acid fluid ejected from the human stomach in three
cases of dyspepsia :
No. 1. No. 2. No. 3.
Grains. Grains. Grains.
Muriatic acid combined with a )
n i I, v > 12-11 12-40 11*25
fixed alkali, . /
Ditto with ammonia, . . 0-00 0-00 5'39
Ditto free, . 5'13 4-63 4-28
Total, 17-24 17-03 20-92*
These conclusions have been objected to by Leuret and Las-
saigne, because, in their opinion, the excess of potash employed
in examining the second portion of the liquid would react upon
the azotic substances present during the calcination, and cyano-
dide of potassium and carbonate of potash would be formed.
These substances would cause a precipitation of the nitrate of
silver, which would increase the apparent quantity of muriatic
acid present.f But it is impossible to doubt that Dr Prout sa-
turated the excess of potash with an acid (probably nitric,) be-
fore he precipitated the muriatic acid by nitrate of silver.
The results of Prout were confirmed by the experiments of Tiede-
mann and Gmelin in 1826.J They distilled the liquid in the sto-
mach of dogs and horses, and found generally free muriatic acid,
together with a quantity of acetic acid, and sometimes of butyric
acid. There was much acetic acid in the stomach of a dog which
had been made to swallow pepper. They found the same acid
in the gastric juice of a horse which had been made to swallow
pebbles. They twice found butyric acid in the gastric juice of
a horse.
Tiedemann and Gmelin examined the liquids in the stomachs
of no fewer than 43 animals, dogs, cats, horses, oxen, calves,
and sheep. It was acid in every case, and the quantity of acid
was always considerable. The acids were usually two in num-
ber, namely, the muriatic and acetic. In ruminating animals
they found also butyric acid.
Leuret and Lassaigne assure us that, when stimulants are
applied to the innermost coat of the stomach or duodenum of a
• Phil. Trans. 1824, p. 45. f Recherches Physiologiques, p. 116 .
\ Recherclies Experimentales, &c. i- p. 91.
GOO FUNCTIONS OF ANIMALS.
living animal, there is always a discharge of a liquid from the
villous extremities so abundant in that coat. This liquid, dis-
charged only when stimulating bodies are applied, or by the
stimulus of food, is, no doubt, the gastric juice, by the agency of
which the food is converted into chyme. It was shown decisive-
ly by the experiments of Dr Stevens, that this juice acts by dis-
solving the food, and that it produces the same effect upon food
out of the body, provided the temperature be kept at 100°, as in
the stomach.
Dr Beaumont of the United States army had an opportunity
of witnessing the process of digestion, and the appearance of the
gastric juice in the stomach of Alexis H. Martin, who had a per-
foration of the stomach, occasioned by a shot. The orifice gra-
dually healed ; but remained open with a kind of valve opening
from without, by means of which any thing could be introduced
into the stomach, and, by pushing the valve aside, the appearance
of the inner coat of the stomach and of the gastric juice could be
examined, and quantities of the gastric juice itself could be ex-
tracted, and its nature ascertained. The facts ascertained by Dr
Beaumont have been stated at considerable length in a preced-
ing chapter of this work, to which the reader is referred.
The gastric juice, as observed by Dr Beaumont, was a pure,
limpid, colourless, slightly viscid fluid. It exhaled a weak odour,
not disagreeable, but slightly aromatic. Its taste was feebly sa-
line, and it always contained an uncombined acid, which Dr
Prout first showed to be the muriatic. The true gastric juice is
secreted only during digestion, and does not exist in the sto-
mach at any other time. What was taken for it by Spallanzani
and other experimenters towards the end of the eighteenth cen-
tury, was merely the saliva mixed with the mucus, secreted to lu-
bricate the stomach, and protect it from the action of certain sub-
stances sometimes present, which might otherwise injure it.
From the experiments of Eberle, M tiller, and Schwann, for-
merly stated, it follows that the gastric juice contains also an-
other substance, called pepsin, some of the most remarkable pro-
perties of which have been detailed in a preceding chapter of this
work. It is by the united action of the muriatic or acetic acid
of the gastric juice, and of the pepsin which it contains, that the
food in the stomach is converted into chyme.
When casein, gelatin, or gluten is put into water, acidulated
DIGESTION. 601
with muriatic or acetic acid, and kept at the temperature of 100°,
solution takes place, and the gelatin loses its property of gela-
tinizing, and of being precipitated by chlorine. But these aci-
dulated liquids are incapable of dissolving coagulated albumen
or fibrin, and likewise to a certain extent casein. To make an
artificial juice capable of dissolving these very common articles
of food, a portion of the third and fourth stomachs of an ox
was digested for twenty- four hours in water, containing 2*75 per
cent, of muriatic acid. It contained in solution 2 '75 per cent, of
solid matter. A portion of this solid matter was pepsin. For
when the liquid thus prepared was digested for some hours on
coagulated albumen in powder, a complete solution was obtained.
It would appear from the present knowledge possessed by phy-
siologists, that the gastric juice, besides salivin, contains a certain
quantity of muriatic acid and pepsin. This liquid, in conse-
quence of the temperature and the peristaltic motion of the sto-
mach, gradually dissolves the food into an opal -coloured and ad-
hesive liquid called chyme.
The chyme thus formed passes into the duodenum, where it is
gradually separated into two distinct substances. 1. A milky
liquid, which is absorbed by the lacteals, under the name of
chyle, and a quantity of excrementitious matter, which gradually
makes its way along the intestinal canal, and at last is thrown out
of the body altogether.
According to Leuret and Lassaigne, a portion of chyle is
formed in the stomach itself. They assure us that, if the stomach
of a living animal be opened during digestion, the white vessels
or lacteals of the stomach are easily seen. They inform us that
they have collected chyle from the lacteals in the stomach of the
horse, and ascertained by experiment that it possesses the usual
properties of that liquid.*
These gentlemen affirm also that, if the duodenum of a living
animal be opened, and a stimulating substance, as vinegar, ap-
plied to its villous coat, a quantity of liquid is immediately se-
creted, similar in appearance to the gastric juice of the stomach.f
If this be a correct statement of facts, there can be little doubt
that the liquor given out by the villous coat of the duodenum
during digestion is destined to act upon the chyme, and to assist
* Recherches surla Digestion, p. 124. f Ibid. p. 140.
G02 FUNCTIONS OF ANIMALS.
in converting it into chyle. But, as the liquid of the duodenum
has never been collected nor examined in a state of purity, little
is known respecting its nature.
Leuret and Lassaigne made a hungry dog swallow small pieces
of sponge wrapt up in fine linen. The animal was killed twenty-
four hours after. Some of the sponges were found in the sto-
mach, and some in the duodenum. The sponges in the stomach
contained a mucous, whitish acid liquid ; those in the duodenum
a liquid which was yellowish, but little viscid, and but weakly
acid. A quantity of this last liquid was mixed with crumb-of-
bread in a phial, and kept for some hours in a temperature of 88°.
In eight hours the bread disappeared, and there remained a thick
homogeneous yellowish liquid, in which iodine detected the pre-
sence of a little starch.* But we have no evidence that the li-
quor thus examined was secreted by the duodenum. Undoubt-
edly the sponges would remain for some time, and would imbibe
liquid in the stomach.
There are two liquids which are poured into the duodenum,
and which are generally considered as intimately connected with
the conversion of the chyme into chyle. These are the pancrea-
tic juice and the bile. An account of both of these liquids, so
far as they have been investigated, has been given in a preceding
part of this work.
The pancreatic juice is not abundant. It was long considered
as similar to saliva; but later investigations have shown that
its nature is different. It is weakly acid, and contains pancreatin
and casein ; but the function of these substances in the process
of digestion or of the conversion of the chyme into chyle is not
yet understood.
Bile consists essentially of choleate of soda. One use of the
soda may be to neutralize the acid contained in the chyme.
But the steps by which the chyme is converted into chyle and
excrementitious matter are not yet understood. Doubtless the
liquids secreted in the duodenum and small intestines perform
the most important part of this extraordinary change. The cho-
leic acid probably unites with the excrementitious matter, increas-
es its consistence, and, by its stimulating qualities, induces the in-
testines to propel it onwards, in order to its expulsion from the
body.
* Recherchcs sur la Digestion, p. 144.
4
DIGESTION. 60S
There are strong reasons for believing that bile is not the only
substance formed in the liver. It has been long known that,
when the liver is diseased, the quantity of urea in the urine is
greatly diminished. Hence it is not unlikely that urea, and
perhaps even uric acid are formed in that organ. Liebig has re-
marked that 5 atoms protein, 15 atoms starch, 12 atoms water,
and 5 atoms oxygen, may be resolved into 9 atoms choleic acid,
9 atoms urea, 3 atoms ammonia, and 60 atoms of carbonic acid.
Thus,
Atoms. Atoms.
5 protein, =C»40Hi80 Az3°07° ^ ( 9 choleic acid, =C3«H197 Az9 O"
15starch, =C180H150 O150 I = J 9 urea, . =C*8 H36 Az'8O18
12 water, = H'2 CM2 ] 3 ammonia, = H9 Az3
5 oxygen, = O5 J 1 60 carbonic acid, =C60 O>*°
But this does not throw much light upon the subject, as we have
no evidence that starch, or any thing resembling it in composi-
tion, exists in the blood, from which the bile and urea are se-
creted.
Liebig affirms that none of the bile is excreted with the faeces.
He conceives that it is all taken again into the system, and con-
verted into carbonic acid and water during its circulation through
the body, for the purpose of producing animal heat. The opi-
nion is bold and ingenious. But its accuracy seems to me to
be belied by the phenomena. The colour of the faeces indicates
the presence of choleic acid, which may have lost its solubility
in alcohol, in consequence of having entered into combination
with the excrementitious matter. Were the bile absorbed into
the system, it ought to be present in the blood, which is never
the case except in the disease called jaundice.
The chyle formed in the lower part of the duodenum and in
the other small intestines is taken up by the open mouths of the
lacteals, and conveyed by them to the thoracic duct. From the
difficulty, or almost the impossibility, of obtaining a sufficient
quarttity of chyle in a state of purity, it has hitherto been but
imperfectly examined by chemists. Indeed, as in the thoracic
duct, it is always mixed with lymph, a liquid exhaled in order to
moisten and lubricate all the shut cavities of the body, from
which it is taken up by the lymphatics, and conveyed to the tho-
racic duct, it is impossible to procure it in a state of purity except
in the lacteals. Hence the quantity of pure chyle procurable
can never exceed a few drops. The facts hitherto ascertained
604 FUNCTIONS OF ANIMALS.
by chemists'and physiologists respecting both chyle and lymph
have been detailed in a preceding chapter of this volume.
Such is the very imperfect view that can be at present given
of the process of digestion. The food in the mouth is converted
into a moist and comminuted mass, which in the stomach is act-
ed on by the gastric juice, and converted into chyme. The
chyme passes into the small intestines, where it is acted on by
liquids, there secreted and converted into chyle and excremen-
titious matter. The part played by the pancreatic juice is un-
known. But the soda of the bile neutralizes the acid in the
chyme, while the choleic acid facilitates the evacuation of the
excrementitious matter from the intestines. The chyle when
completed is taken up by the lacteals, carried to the thoracic
duct, where it is mixed with the lymph, and both together are
conveyed to the left subclavian vein, where they mingle with the
blood, and during the circulation through the blood-vessels, the
conversion of the chyle into blood is completed.
CHAPTER II.
OF RESPIRATION.
THE function of respiration, so essential to the existence of
hot-blooded animals, and indeed of all animals, could not be un-
derstood till after the discovery of the circulation of the blood.
Accordingly, there is nothing respecting this function in the
writings of the Greek philosophers that is deserving of being
noticed. Plato, in his Timeus, says, that, " as the heart might
be easily raised to too high a temperature by hurtful irritation,
the genii placed the lungs in its neighbourhood, which adhere
to it and fill the cavity of the thorax, in order that their air ves-
sels (arteries) might moderate the too great heat of that organ,
and reduce the vessels to an exact obedience." And this opi-
nion respecting the use of the lungs, strange as it may appear,
was generally adopted by philosophers and medical men, till the
chemical discoveries respecting heat made by Dr Black about
the middle of the last century laid the foundation of another ex-
planation.
The structure of the lungs seems to have been first explained
3
RESPIRATION. 605
in a satisfactory manner by Malpighi, in his two epistles De Pal-
mombus, first published in 1661. He showed that the interior
portion of the lungs was composed of lobules, in the intervals
between which were numerous vesicles communicating with each
other, and with the branches into which the trachea is divided,
and consequently always filled with air. These vesicles are lin-
ed with blood-vessels, which expose the blood from the right
ventricle of the heart to the action of the air. This structure of
the lungs was confirmed by the subsequent dissections of Tho-
mas Bartholin ; though he had previously held a contrary opi-
nion.
After the structure of the lungs was ascertained, some time
elapsed before anatomists were agreed about the mechanism of
respiration. Swammerdam, in 1667, adopted the opinion of
Des Cartes, according to whom the air is forced into the lungs
by the increased density of the air around the breast, occasioned
by the dilatations of the thorax, in consequence of the elevation
of the ribs. This absurd theory seems to have been first refut-
ed by Dr Walter Needham, in his celebrated work De Formato
Fcetu, published in 1667. In 1674, it was examined and opposed
at greater length by Dr Lamzweerde, a physician in Cologne.
The true mechanism of respiration, the elevation of the ribs, and
the action of the intercostal muscles * were pointed out. It was
shown that, by the elevation of the ribs, and the depression of
the diaphragm, a partial vacuum is produced in the thorax. This
causes the air to be forced into the vesicles of the lungs. That
organ, of consequence, is pressed against the walls of the thorax,
and its cells at every inspiration are filled with air.
It has been already stated, that the almost universal opinion
of physiologists was, that the use of the lungs was to cool the
blood. The chyle was supposed to be converted into blood in
the liver. One of the first steps towards explaining the nature
of respiration was made by Dr Hooke, in his Micrographia, pub-
lished in 1665. He gives a theory of combustion in that work,
which applies very closely to the opinions entertained on the sub-
ject by modern chemists. The air, according to him, contains
a small quantity of a peculiar matter, identical with a substance
which exists in nitre. This substance has the property of rapid-
ly dissolving combustibles, and the phenomena of combustion are
* De Respiratione, p. 278.
606 FUNCTIONS OF ANIMALS,
occasioned by this rapid solution. When the substance is satu-
rated with the combustible body, it becomes unfit for supporting
combustion, and of course no combustible body will burn in it.
This peculiar substance is obviously the oxygen of modern che-
mists, which is now known to constitute a fifth part of the volume
of common air.
In 1664, Dr Malachi Thruston, when he took his medical de-
gree at Cambridge, defended a thesis entitled De Respirationis
usu Primario Diatriba, which he published three or four years
afterwards.* He was of opinion that the air, or the purest por-
tion of it, was absorbed by the blood in the lungs, and that this
portion was necessary to preserve the fluidity and the heat of that
liquid. The heat of the body, he says, is owing to the nitrous
particles of the air absorbed by the blood, which ferments with
the sulphureous particles. He observed that the blood acquir-
ed its scarlet colour by its union with air, and says it was with
peculiar pleasure that he found that the experiments of Lower
agreed with his ideas. Now Lower's work on the heart was pub-
lished in 1669. Hence I think we may conclude that Thrus-
ton's Diatriba was not given to the public before the year 1669
or 1670.
In 1668, Dr Mayow of Oxford published his Tracts, which
have conferred upon him so much posthumous celebrity, after he
had languished in obscurity for more than a century. This work
consists of five tracts. The first, De Sal-nitro et Spiritu Nitro
(Brio, in which he treats of the constitution of air, and gives a
theory of combustion very similar to that of Dr Hooke. His se-
cond tract, De Respiratione, and his third, De Respiratione Foetus
in Utero et Ovo, contain his views respecting that most important
function. According to him the nitro-aerial particles (that is
the oxygen) of the atmosphere are absorbed by the blood in the
lungs. During the circulation, they unite with the salino-sul-
phureous particles of the blood. This union is accompanied by
fermentation, which evolves animal heat.
The dark and dusky colour of venous blood is, in his opinion,
owing to the salino-sulphureous particles. Fermentation he con-
sidered as depending upon the nitro-aBrial particles, and hence he
inferred that the motion of the blood was owing to the same
source. The chief use of respiration was, in his opinion, to keep
* It was inserted in the Bibliotheca Anatomica printed in 1685.
RESPIRATION. 607
up the motion of the heart and arteries. These views he illus-
trated and confirmed by many ingenious experiments, in which
he anticipated some of the modern discoveries respecting respi-
ration.
Lower's work, De Corde item de Motu et Colore Sanguinis et
Chyli in earn Transitu, was published in 1669 ; or a year after
Mayow's tracts.* In this very ingenious treatise, he proves that
the florid colour of arterial blood is owing to the absorption of
air, or rather the nitrous spirit of air (oxygen) in the lungs.
This nitrous spirit is dissipated during the circulation. Hence
the reason of the dark colour which the blood has when it enters
the right auricle and ventricle before it passes to the lungs, where
it is again impregnated with air, and reassumes its florid colour.
It is well known that carbonic acid gas was obtained in a se-
parate state by Dr Black, and that he ascertained that, when
passed through lime-water, it has the property of rendering it
turbid and milky. In the year 1757, by breathing through lime-
water, he ascertained that the air when thrown out of the lungs
contains carbonic acid.f In 1774, Dr Priestley discovered oxy-
gen gas, and found that animals could breathe it much longer
with impunity than the same bulk of common air. He found that
the quality of air was deteriorated by breathing precisely as by
combustion. According to him, when atmospheric air is com-
pletely deprived of phlogiston, it becomes oxygen gas ; when
completely saturated with phlogiston, it becomes azotic gas.
Blood exposed to air acquires a florid red colour, while, at the
same time, the air is deteriorated. Hence he conceived that the
use of respiration was to deprive the blood of phlogiston. :£ It is
curious, that, in the year 1776, he does not seem to have been
aware of the formation of carbonic acid gas during respiration,
though the fact had been noticed by Dr Black as early as the
year 1757.
About the year 1780, Lavoisier published his experiments on
* Yet Mayow quotes Lower in confirmation of his views. My copy of Mayow
is the second edition, printed (I believe, for the title-page is wanting,) in 1674 ;
and my copy of Lower is that in the Bibliotheca Anatomica, printed in 1685.
Doubtless additions were made to the new editions. Hence, unless we had the
original editions, it would be impossible to ascertain who first struck out the
ideas nearly identical stated by Thruston, Mayow, and Lower.
•f- Black's Lectures, ii. 87. f Priestley on Air, (first series), iii. 55.
608 FUNCTIONS OF ANIMALS.
the respiration of animals.* He considered atmospherical air
as a mixture of oxygen and azotic gases. He showed that, during
respiration, the azotic portion of the air remained unchanged,
but the oxygen portion diminished, and the portion which dis-
appeared was replaced by carbonic acid gas. Thus he verified
the fact discovered by Black, and rectified the statements of
Priestley. Lavoisier considered respiration as a true combus-
tion. In the lungs, the carbon of the blood combined with the
oxygen of the air, and converted it into carbonic acid gas, just
as happens when charcoal is burnt.
In the year 1788, an important treatise was published by Dr
Edmond Goodwyn, entitled On the connection of Life with Res-
piration.^ He endeavoured to determine the capacity of the
lungs, the quantity of air which they contain, and the volume
drawn in and emitted in ordinary respiration. But some of his
estimates of these seem to have far exceeded the true average
quantities. In the year 1790, appeared Dr Menzies's Tentamen
Inaugurate de Respiratione, originally printed as a thesis when he
graduated in Edinburgh, but afterwards, I believe, published in
an English dress. J He endeavoured to determine the capacity
of the lungs, the quantity of air drawn in and thrown out at
each respiration, and the volume of oxygen gas converted into
carbonic acid gas with more accuracy than had been done by
Goodwyn, though I doubt whether he was successful. The latest
experiments of Lavoisier and Seguin on respiration were pub-
lished by Seguin in the Memoirs of the French Academy for
1789, (p. 566.)§
I shall not continue this historical detail any farther. The
facts ascertained by Davy, Allen and Pepys, Prout, Berthollet,
&c., will be noticed as we proceed.
The fluid respired by animals is common atmospherical air ;
and it has been ascertained by experiment, that no other gaseous
body with which we are acquainted can be substituted for it. All
the known gases have been tried ; but they all prove fatal to the
* Mem. de 1' Academic des Sciences, 1777, p. 185.
f It is said to have been written in consequence of a prize offered by the Hu-
mane Society for the best essay on the method of recovering persons apparent-
ly drowned.
| But I have only seen the Latin thesis printed by Menzies when he gra-
duated at Edinburgh in 1790.
§ A posthumous volume published after the abolition of the Academy.
RESPIRATION. 60(J
animal which is made to breathe them. Gaseous bodies, as far
as respiration is concerned, may be divided into two classes : I.
Unrespirable gases ; II. Respirable gases.
I. The gases belonging to the first class are of such a nature
that they cannot be drawn into the lungs of animals at all ; the
epiglottis closing spasmodically whenever they are applied to it.
To this class belong carbonic acid, and probably all the other
acid gases, as has been ascertained by the experiments of Pilatre
de Rozier.* Ammoniacal gas belongs to the same class ; for
the lungs of animals suffocated by it were found by Pilatre not
to give a green colour to vegetable blues. f
II. The gases belonging to the second class may be drawn
into the lungs, and thrown out again without any opposition from
the respiratory organs ; of course the animal is capable of re-
spiring them. They may be divided into four subordinate clas-
ses; 1. The first set of gases occasion death immediately, but
produce no visible change in the blood. They occasion the ani-
mal's death merely by depriving him of air, in the same way as
he would be suffocated by being kept under water. The only
gases which belong to this class are hydrogen and azotic. 2.
The second set of gases occasion death immediately, but at the
same time they produce certain changes in the blood, and there-
fore kill not merely by depriving the animal of air, but by cer-
tain specific properties. The gases belonging to this class are
carburetted hydrogen, sulphuretted hydrogen^ carbonic oxide, and
perhaps also nitrous gas. 3. The third set of gases may be
* Jour, de Pbys. xxviii. 418. Pilatre de Rozier went into a brewer's tub
while full of carbonic acid gas evolved by fermentation. A gentle heat mani-
fested itself in all parts of his body, and occasioned a sensible perspiration. A
slight itching sensation constrained him frequently to shut his eyes. When he
attempted to breathe, a violent feeling of suffocation prevented him. He sought
for the steps to get out ; but not finding them readily, the necessity of breath-
ing increased, he became giddy, and felt a tingling sensation in his ears. As
soon as his mouth reached the air he breathed freely, but for some time he could
not distinguish objects ; his face was purple, his limbs weak, and he understood
with difficulty what was said to him. But these symptoms soon left him. He
repeated the experiment often ; and always found, that, as long as he continued
without breathing, he could speak and move about without inconvenience ; but
whenever he attempted to breathe, the feeling of suffocation came on. Ibid,
p. 422.
f Jour, de Phys. xxviii. p. 424.
f See Chausier's experiments, ibid. Ivi. p. 35.
Qq
610 FUNCTIONS OF ANIMALS.
breathed for some time without destroying the animal, but death
ensues at last, provided their action be long enough continued.
To this class belong the nitrous oxide and oxygen gas.* 4. The
fourth set may be breathed any length of time without injuring
the animal. Air is the only gaseous body belonging to this class.
Let us now endeavour to state the phenomena of respiration
with as much precision as possible :
1. From the experiments of Messrs Allen and Pepys, it ap-
pears that the lungs of a stout man about five feet ten inches
high, after a full expiration, still retain 108 cubic inches of air. f
The previous determination of Goodwyn very nearly agrees with
this. He reckoned the air in the lungs after an expiration, to
be 109 cubic inches.:]:
In order to discover the capacity of the lungs, I made twelve
individuals, young men from fourteen to thirty-three years of
age, make a full inspiration and then expel from the lungs as
much air as they could. The following table exhibits the results :
1. • . 100 cubic inches.
2. ... 140
3. . . 163
4. ... 180
5. . . 193
6. ... 200
7. :>: ^ . 200
8. .,,.>. . . 200
9. . . 200
10. . . . 200
11. . . 210
12. . . 250§
The individual who could expel only 100 cubic inches of air
* Perhaps also nitrous gas might have the same effect, if it could be breathed
by an animal whose lungs contained no oxygen.
f Phil. Trans. 1809, p. 410. J Goodwyn on Respiration, p. 27.
§ Mr Thackrah mentions a tall young cornet who was able to throw out 10|
pints of air from his lungs. If he means wine pints, as is likely, the quantity
thus thrown out was 296 cubic inches. See Thackrah on the effects of different
arts, trades, and professions on health, p. 16- He reckons the average in adults
to be 219 cubic inches. He says that the capacity of the female chest is less
than that of the male, which he ascribes to the wearing of tight stays. The
mean quantity of air thrown out of the chest of ten females aged 18£, and in
good health, by a forced expiration, was 3£ pints, or only 10 i cubic inches.
Ibid. p. 96.
RESPIRATION. 6ll
from the lungs after a full inspiration, was a girl about fifteen
years of age. The two who expelled 140 and 163 were my two
sons, the first aged fourteen, the second aged twelve. The indi-
vidual who expelled only 180 cubic inches was a very thin spare
gentleman aged twenty-one. I myself could only expel 193 cu-
bic inches from the lungs after a full inspiration. These expe-
riments were often repeated with the same individual, and the
quantity of air which he was able to expel from the lungs after
a full inspiration was always the same. The mean of the whole
is 186^ cubic inches, or if we leave out the girl, who only made
one trial, as the quantity expelled was so small, the average will
be 194 cubic inches; or very nearly the quantity, which I my-
self was able to expel from the lungs by a forced expiration af-
ter a full inspiration. If to this we add the 108 cubic inches
which Allen and Pepys found to remain in the lungs after the
full expiration which accompanies death, the quantity of air which
the lungs are capable of containing, will be 302 cubic inches.
The quantity of air employed in respiration during a given
time will of course depend upon the number of inspirations and
expirations per minute. Now these differ considerably in dif-
ferent individuals. Dr Hales reckons them at twenty in a minute.
A man on whom Dr Menzies made experiments, breathed only
fourteen times in a minute. Sir H. Davy informs us that he
made between 26 and 27 in a minute. I myself make about
1 9 at an average. The average of all is 20. Now 20 in a mi-
nute make 28,800 in 24 hours.
There is a great diversity in the statements of different expe-
rimenters respecting the quantity of air which an ordinary sized
man draws into the lungs at a single inspiration, and again ex-
pels by an ordinary expiration. Dr Menzies concluded from
the mean of 56 trials that the quantity of air drawn into the
lungs at each inspiration is about forty cubic inches. And Dr
Jurin had long before estimated the quantity at forty cubic inches.
The experiments of Allen and Pepys, made with great care and
upon a large scale, give the quantity only 16^ cubic inches. Dr
Goodwyh reckons it from his own experiments at fourteen cubic
inches.* Borelli had previously estimated it at eighteen or twenty
cubic inches.f I tried the quantity of air which I myself drew in-
* Goodwyn on Respiration, p. 34. | As quoted by Menzies in his Thesis.
FUNCTIONS OF ANIMALS.
to my lungs by an ordinary inspiration. The mean of a great
many trials, made with as much care as possible, gave sixteen^cu-
bic inches. I caused a tall and stout man with an expanded chest
to accustom himself to breathe through a tube without any ef-
fort. The quantity which he expelled at a single expiration was
also sixteen cubic inches. From these trials, corroborated as
they are by the experiments of Allen and Pepys, I am dispos-
ed to conclude that the quantity of air drawn into the lungs at
each inspiration is sixteen cubic inches, or about T^th of the whole
air that the lungs are capable of containing. Now, as the num-
ber of inspirations in 24 hours is 28,800, it is clear that the vo-
lume of air taken into the lungs in 24 hours averages 240,800
cubic inches, or 266f cubic feet, or 10§ avoirdupois Ibs. weight
of air.
2. There is a great diversity in the opinion of different expe-
rimenters respecting the ratio which subsists between the volume
of air inspired, and that which is expired. According to Davy,
air, by a single inspiration and expiration, is diminished from ^th
to jfio th part of its bulk.* In the numerous and accurate expe-
riments made by Allen and Pepys on a very large scale, the
average diminution was little more than half a per cent, and
even this seems to have been owing rather to unavoidable inac-
curacy than to real absorption. In the experiments of Berthol-
let, conducted also with very great care, the diminution varied from
0*69 to 3*70 per cent.f I made many years ago numerous ex-
periments by enclosing animals in a large glass receiver, through
which a gentle current of atmospherical air was constantly pass-
ing. On making the requisite allowance for the absorption of a
little carbonic acid gas by the water in the vessels through which
the air passed, I found that there was no diminution whatever in
the volume of air by passing it through the lungs. But the case
was very different when an animal was confined in a bell glass,
and obliged to breathe the same air for a long time. The volume
was always diminished, and the diminution always increased as
the quantity of air which the animal breathed was diminished.
In one case a rabbit was made to breathe a very small quantity
of air. The animal died almost immediately ; but the volume of
the air was reduced to one-third of its original bulk. From
these experiments it may, I think, be concluded that in ordinary
* Davy's Researches, p. 431. f Mem. d'Arcueil, ii. 461.
RESPIRATION. 613
respiration the air drawn into the lungs is nearly balanced by the
air thrown out But when the animal is placed in untoward cir-
cumstances, and is obliged to make forced inspirations, the bulk
of the air is diminished, and this diminution is inversely as the
volume of the air which the animal is obliged to breathe.
3. It is well-known that atmospherical air (abstracting a little
vapour of water and a trace of carbonic acid gas) is composed of
eighty volumes azotic and twenty volumes oxygen gas. But
when it is thrown out of the lungs by expirations, the volume of
oxygen gas is diminished, being replaced by exactly the same
bulk of carbonic acid gas. Various experiments have been made
to ascertain how much of this principle is lost by respiration in a
given time ; but they by no means correspond with one another.
Indeed, it is extremely probable, if not absolutely certain, that
the degree of effect which the same animal produces upon the air
respired differs materially at different times, and in consequence of
different circumstances. Nothing, therefore, beyond an approxi-
mation can be expected from our experiments on this function.
Dr Menzies was the first who attempted to ascertain the quan-
tity of oxygen consumed by a man in a day. According to him,
36 inches are consumed in a minute, and of course 51,840 inches
in twenty-four hours.* This estimate exceeds that obtained by
Lavoisier and Davy from their experiments. Lavoisier and Se-
guin estimate the quantity of oxygen consumed by a man in
twenty-four hours at 46,037 cubic inches, and this nearly coin-
cides with the results which Lavoisier obtained from his last ex-
periments, on which he was occupied when he was dragged to the
place of execution. With this also the experiments of Davy co-
incide very well. He calculates that 3 1 *6 inches of oxygen are
consumed in a minute, which, in twenty-four hours, make 45,504
inches.f
But these determinations can be considered only as approxi-
mations. Upon examining the air expired from my own lungs,
I found that the volume of carbonic acid gas which it contained
differed considerably from day to day. In the month of May
1832, I analyzed air from my own lungs on ten consecutive days,
between eleven and twelve o'clock each day. The following ta-
ble exhibits the result : J
* Bostock on Respiration, p. 81. f Davy's Researches, p. 433.
\ Records of General Science, i. p. 28.
614 FUNCTIONS OF ANIMALS.
Carbonic acid gas.
1st day, . 4 '64 per cent.
2d . 4-70
3d . 6-07
4th . 3-27
5th, . 5-26
6th . 2-05
7th . 2-39
8th . 3-85
9th . 3-05
10th . 7-16
The volume of carbonic acid gas, and, consequently, the con-
sumption of oxygen gas on the tenth day, was three and a-half
times greater than on the sixth day. The mean of the whole was
4*24 per cent. I made ten gentlemen, who were at that time
operative chemists in my laboratory, breathe into a glass tube
filled with mercury, and analyzed each portion of air thus ob-
tained. The trials were made about eleven o'clock of the day.
The results were as follows :
Carbonic acid gas.
Mr Thomas Thomson, (aged 14), 3-06 per cent
Ditto, next day, . 3-61
Mr J. Colquhoun, (aged 18), . 3-09
Mr Forrest, (aged 18), . 2-10
Ditto, next day, . . 5*19
Mr Coverdale, (aged 18), . 2*54
Ditto, next day, . . 1-71
Mr Cargill, (aged about 30), . 4-68
Mr Bruce, (aged about 20) . 5-46
Dr Duncan, (aged about 21), . 6-17
Dr Short, (aged about 40), . 6-85
Mr Frazer, (aged about 30) . 7*08
Two ladies allowed me to examine the air from their lungs.
The result was as follows :
Carbonic acid gas.
First lady, . 2-85 per cent.
Second lady, . 4-06
The diversity in the volume of carbonic acid gas, and^conse-
quently of the quantity of oxygen gas consumed by respiration,
is fully as great as in my own case. The average of the whole
RESPIRATION. 615
is 4*16 per cent, of carbonic acid gas in the air expired from the
lungs. Now, this does not differ much from 4*24, the average
in my own case of ten days at eleven o'clock. I am disposed,
therefore, to consider 4*24 per cent, as the average volume of
oxygen gas converted into carbonic acid gas at eleven o'clock, or
rather between eleven and twelve in the forenoon.
4. Dr Prout has shown by a number of well-conducted expe-
riments on himself, that the proportion of carbonic acid formed
at each inspiration is different at different periods of the day. It
is at its maximum nearly about noon, and is at its minimum
about midnight. It appears farther from his trials that the quan-
tity of carbonic acid gas in expired air begins to increase nearly
at twilight. The following table exhibits the proportion per cent,
of carbonic acid in the air expired from his lungs during every
hour of the day. The experiments from which it was deduced
were made in August :*
Carbonic Carbonic
Hour A. M. acid per cent. Hour p. M. acid per cent- •
6 . 3-43 . 6 . 3-40
7 . 3-48 . 7 . 3-35
8 . 3-56 . 8 . 3-32
9 . 3-66 . 9 . 3-30
10 . 3-78 . 10 . 3-30
11 . 3-92 .11 . 3-30
12 . 4-10 . 12 . 3-30
1 . 3-98 . 1 . 3-30
2 . 3-80 . 2 . 3-30
3 . 3-65 . 3 . 3-30
4 . 3-54 . 4 . 3*33
5 . 3-46 . 5 . 3-38
Mean, 3-45
Dr Prout found that alcohol and all fermented liquors diminish-
ed the proportion of carbonic acid formed by respiration, and this
was confirmed by the experiments of Dr A. Fyfe. They found
likewise' that when the constitution is affected by mercury, the
proportion of carbonic acid gas in the air expired is diminished.
Dr Fyfe found that the quantity was likewise diminished by a
course of nitric acid, and by a vegetable diet.f Mr Macgregor
* Annals of Philosophy, ii. 328, and iv. 321. t Ibid. iv. 334.
61 6 FUNCTIONS OF ANIMALS.
ascertained that the air expired by persons ill of confluent small-
pox contained as much as eight per cent, of carbonic acid gas.
During the eruptive fever of measles it amounted to from four
to five per cent. In proportion as health was resumed, the
per centage diminished. In chronic skin diseases, an aug-
mentation was also observed, and in one case of ichthyosis the
mean per centage was 7*2. In diabetes, no aberration could be
detected. *
A set of experiments upon the same subject has been publish-
ed by Mr Coathupef in 1839. His apparatus was simple and
excellent, and the experiments appear to have been conducted
with great care. They were continued for a week. The fol-
lowing is the result obtained :
Carbonic acid per cent,
of air exposed.
From 8 o'clock
A. M. tO 9^
4-37
10
to 12
3-90
12 noon,
to 1
3-92
2 P. M.
to 51
4-17
7 P. M.
9 P. M.
to 8J . 3-63
to midnight, 4-12
Mean, 4-02
These experiments do not agree with Dr Prout's, and show
the necessity of repeating them upon many individuals before
any general conclusions can be drawn.
From the experiments of Prout, it appears that the quantity
of carbonic acid gas produced by respiration is at its maximum
at noon, and that its quantity at 1 1 A. M. is to the mean quantity
for twenty-four hours as 3*92 to 3*45. Hence it follows that the
mean volume of carbonic acid gas in 100 volumes of air expired,
deduced from the preceding experiments, is 3*72.
From the experiments of Boussingault, it would appear that
a cow in twenty -four hours discharges by the lungs about five
times as much carbon as a man does.f A horse discharges
about six times as much.
Now, if the preceding estimate of the quantity of air drawn
* Atheneum, No. 677, p. 822. + Phil. Mag. (3d series), xiv. 401.
| Ann. de Chim. et de Phys. Ixxi. 126,
"RESPIRATION. 617
into the lungs at each inspiration be accurate, it will follow, that
in twenty-four hours 8957*76 cubic inches of oxygen gas are
converted into carbonic acid gas by the respiration of every adult,
but 8957*76 cubic inches of carbonic|acid weigh 4234 grains,
and contain 1155 grains, or very nearly one-sixth of a pound
avoirdupois, or two ounces and two-thirds of carbon. This, then,
is the amount of carbon discharged^every twenty-four hours from
the body by means of the lungs.
If we reckon the quantity of blood in the body of an adult
twenty-six pounds, and that dry blood amounts to twenty per
cent of liquid blood, it is obvious that, if the carbonic acid were
derived from the carbon of blood (constituting 51*96 of dry
blood,) the whole carbon would be consumed in little more than
sixteen days.
5. The general opinion at present entertained is, that the vo-
lume of oxygen gas which disappears is greater than that of
the carbonic acid gas, which replaces it. If, as is most pro-
bable, the oxygen gas is absorbed by the blood in the lungs, and
combining with carbon during the circulation, and is evolved in the
state of carbonic acid gas when the blood passes next through
the lungs, it is at least possible that a portion of the oxygen gas
absorbed may combine with hydrogen during the circulation and
form water. The experiments of Despretz, which will be stated
afterwards, lead to the conclusion that about Tlath of the oxy-
gen gas absorbed combines with hydrogen and forms water, and
that T9(jths of it go to the formation of carbonic acid gas. If
this estimate be true we must, tjn order to get the true volume
of oxygen gas abstracted from air during respiration, augment
the volume of carbonic acid gas evolved by ^th. This would
make the average quantity of oxygen abstracted from the air in-
spired amount to 4-092 per cent.
When venous blood passes through the lungs it becomes ar-
terial blood, distinguished by its bright scarlet colour. Now, as
the colouring matter of blood is the red globules, it is obvious
that they must be the portion of the blood which has absorbed
oxygen. The blood continues arterial till it passes through the
capillary vessels. Here it loses its scarlet colour and becomes
venous blood. In the capillaries, therefore, the oxygen which
has combined with the globules must be converted into carbonic
618 FUNCTIONS OF ANIMALS.
acid. Liebig conceives that it is the iron in the globules which
combines with the oxygen. It thus becomes peroxide. In the
capillaries the half atom of oxygen with which it had united
unites with carbon, and is converted into carbonic acid. This
carbonic acid combines with the protoxide of iron. In the lungs
the carbonic acid is displaced by the oxygen of the atmosphere,
and passes into the air, while an equal volume of oxygen gas
unites with the protoxide, and converts it into red oxide. This
explanation is certainly very ingenious.
6. The air when emitted from the lungs has probably the
temperature of that organ, or is heated to about 98°. It is load-
ed with moisture at that temperature. Now the force of the
vapour of water at 98° is 1 74 inch. Hence it follows that the
air expired from the lungs contains rather more than -^th of its
volume of vapour, or every 100 cubic inches of air expired will
contain 5*9 cubic inches of vapour. But the specific gravity of
vapour at 98° is 0-0362, that of air being 1. This is nearly 2^th
part of the weight of the same volume of air. Hence the weight
of the aqueous vapour in every 100 cubic inches of air expired
is about 1*8 grain. This in 24 hours will amount to 4334 grains,
or somewhat more than 9 avoirdupois ounces. Such is the
quantity of moisture given out daily from the lungs of an adult
person.
MM. Henri and Chevalier collected a quantity of the matter
of expiration of cows which had condensed on the ventilators of
a cow-house in Paris. It was a colourless liquid having an am-
rnoniacal smell. It contained no salt of lime, potash or soda,
but only salts of ammonia. These salts were,
Lactate ^
Carbonate /.
. > of ammonia,
Acetate
Hippurate
Also a balsamic volatile body from the dung of the cattle in the
stable. It is more than probable that the ammonia and the
acids combined owed their origin to the dung or urine of the
cattle rather than to what was expired from the lungs.*
7. The opinion at present entertained respecting the effect of
respiration upon the azotic constituent of the air is not very de-
cided. Some suppose that the azote of the air is not affected by
* Jour, de Pharm. xxv. 421.
4
RESPIRATION. GlQ
respiration, others affirm that a portion of it is absorbed as well
as of the oxygen. While a third party, and that by far the most
numerous, conceive that a portion of azotic gas is emitted from
the blood in the lungs ; that this portion just balances the por-
tion of oxygen which has combined with hydrogen, and thus pre-
vents any diminution in the bulk of the air from becoming sen-
sible.
If we adopt the view of Dr Priestley and Professor Liebig,
that a great deal of air is carried to the stomach by the saliva,
and that this air makes its way into the blood, and that its azo-
tic portion is emitted in the lungs in a gaseous form, we see a
source for the origin of the azotic gas that may be evolved in
the lungs.
It is obvious that the 108 cubic inches of air remaining in the
lungs after a full expiration, must contain less than the normal
quantity of oxygen. Hence, even admitting that the azote of
the air is not affected by respiration, still the air expired would
appear to contain an excess of azote, or a greater bulk than ex-
ists in common air. I think it not unlikely that this may be the
reason of the apparent increase of azotic gas in the air expired.
8. It is most probable that the blood, as it passes through the
lungs, absorbs oxygen from the air inspired ; and that, during
the circulation of the blood through the capillary vessels, this
oxygen is converted partly into carbonic acid and partly into wa-
ter. Tiedemann and Gmelin suppose that this carbonic acid com-
bines with the soda of the blood, and is displaced during the cir-
culation by lactic acid, while the lactate of soda is decomposed in
its turn by urea. This hypothesis, or something very like it, has
been embraced by Dumas. But Liebig's explanation given above
is more plausible. We do not know enough respecting the nor-
mal state of the constituents of blood, consisting chiefly of albu-
men and cruorin, to be able to point out the change effected by
this abstraction of carbon and hydrogen.* But there is reason
* MM. Macaire and Marcet analyzed dried arterial and venous blood, and
oundthat venous blood contained more carbon and less oxygen than arterial blood.
Dried arterial blood. Dried venous.
Carbon, . 50-2 55-7
Azote, . 163 16-2
Hydrogen, . 6-6 6*4
Oxygen, . 26 -3 21-7
99-4 100-0
See Mem. de la Societe de Phys. ct d'Hist. Nat. de Geneve, v. 223.
620
FUNCTIONS OF ANIMALS.
to believe that the oxygen absorbed by the blood in the lungs is
the cause why it acts as a stimulus to the heart, and makes it to
contract. For the action of the heart, and consequently the cir-
culation of the blood, immediately ceases when respiration is pre-
vented. This is doubtless the reason why respiration is so essen-
tial to life, that when it is suspended for even a very short time,
death ensues.
A great number of experiments have been made on the respi-
ration of fishes by Prove^al and Humboldt.* It is well known
that these animals require oxygen gas as well as other animals,
and that if the water in which they are be deprived of the whole
of its air, they die very speedily. Prove^al and Humboldt em-
ployed for their experiments the waters of the Seine. They se-
parated the air from a quantity of it by boiling, and subjected it
to a chemical analysis. Into another quantity of the same water,
tenches were put and confined for several hours till they began
to suffer ; they were then withdrawn, and the air separated from
the water in which they had lived, and subjected to chemical ana-
lysis. In every case a portion, both of oxygen and azote had
disappeared, and a quantity of carbonic acid had been formed.
The following table exhibits the results of a variety of their ex-
periments :
Z
The fishes ig Q.
3 J3
o.
2
have £l o
1 c^
.t3
55 bt
ON S* '"'
Nature of
the gases.
^L-
1
I
8
|
-0
11
cs c
1 s'l
No. of fishes
and time.
i §
o
|
1
11
o-c
Q
Q
<
PH
< 0
0 g 1
Total,
Oxygen,
Azote,
Carbonic ac.
175-0
52-1
1159
7-0
135-1
5-6
95-8
33-7
39-9
46-5
20-1
26-7
43
57
Three tench-
esduring5h.
5 minutes.
Total,
524-0
404-0
119-6
Oxygen,
155-9
44-0
__
111-9
Seven tench
Azote,
347-1
249-5
—
97-6
87
80
esduring6h.
Carbonic ac.
21-0
110-9
—
—
89-9
~~
—
Total,
5240
153-0
71-0
_
«._
Oxygen,
Azote,
155-9
347-1
10-5
289-5
__
145-4
57-6
—
40
91
Seven tench-
es during5h
Carbonic ac.
21-0
153-0
—
—
132-0
—
—
Mem- d'Arcueil, ii. 259.
3
RESPIRATION.
621
|
The fishes
J3 o 1 => -P •
JT
2
have
•w £5
2 'a
Nature of
g
-3
|j?
£gj
No. of fishes
the gases.
1
&
|
TJ
1
J-a
'« °'J
and time.
Gases I
riment.
o
B
5
3
1
Produc
Azote a
oxygen
It!
Total,
Oxygen,
Azote,
483-0
143-7
3200
345-5
4-2
294-1
137-5
139-5
25-9
—
19
—
One tench
during 17
Carbonic ac.
19-3
47-2
—
27-9
—
20
hours.
Total,
Oxygen,
Azote,
483-0
143-7
320-0
408-0
626
2854
75-0
81-1
34-6
—
43
—
Three tench.
es during 7^
Carbonic ac.
19-3
60-0
—
—
40-7
—
50
hours.
Total,
Oxygen,
Azote,
4830
1437
320-0
398-6
40-0
246-6
84-4
103-7
73-4
—
11
—
Three tench-
es during 5
Carbonic ac.
19-3
1120
—
—
92-7
— •
89
hours.
Total,
483-0
3725
110-5
___
___
__
Oxygen,
143-7
37-8 i —
105-9
—
Two tenches
Azote,
320-0
252-9 i —
67-1
63
— during 7 h.*
Carbonic ac.
19-3
81-8 —
—
62-5
—
59
The quantity of gas obtained from the Seine water was, at an
average, 0-0275 of its bulk, or not quite ^th part ; the average
quantity of oxygen which this gas contained was 0'310.
From these experiments it appears, that the respiration of fishes
differs very much from that of other animals. The oxygen is
not merely converted into carbonic acid, as happens during the
respiration of men and the larger animals ; but a portion of it
is absorbed and introduced into the system. A portion also of
azote is absorbed. The quantity of air consumed by fishes is ex-
tremely small, when compared with that consumed by terrestrial
animals. This will appear from the following table, in which
the bulk of the air consumed, and of the carbonic acid formed
in an hour, is stated in cubic inches :
Oxygen in
Hours
Absorption
in 1 hour
Carb. ac.
air after the
No. of
the expert, in cubic
inches.
produced, in
Time.
expert.
fish.
lasted.
Oxygen.
Azote.
cub- in.
28 Feb.
0-056
3
*i
0-0245
0-0106
00140
3 March;
0-151
7
6
00221
00192
00177
7 March,
0-034
7
H
0-0185
11 March,
0-017
1
17
0-0679
0-0126
0-0136
28 Feb.
0-178
3
7£
0-0298
00123
0-0150
24 Feb.
0141
3
5
0-0575
00405
0-0512
20 Feb.
0-130
2
7
0-0635
0-0397
0-0370
* The numbers in this table indicate cubic centimetres,
is equal to 0-0610 of a cubic inch.
A cubic centimetre
FUNCTIONS OF ANIMALS.
From this table, compared with the facts stated in the preced-
ing part of this section, it follows, that in a given time a man
consumes 50,000 times as much oxygen gas as a tench. Yet the
presence of this principle is equally necessary for the existence
of both.
The experiments of M. Nysten on the effect of injecting oxy-
gen gas into the veins of living animals, made in 1811, show
that blood readily absorbs this gas. It would be an important
fact if it could be ascertained whether injections of oxygen gas
into the veins of living animals could be so far substituted for
respiration as to prolong the life of the animal. It would be
difficult, however, to make such an experiment in an unexception-
able manner. Were as much oxygen gas as the blood would
readily absorb injected into the veins of an animal, and were the
animal, together with another in its natural state, plunged into
a vessel filled with hydrogen gas, it might perhaps be ascertain-
ed whether the former would live longer than the latter.
An interesting set of experiments, which throws considerable
light on respiration, was made by M. Boussingault in 183 P. * A
cow giving milk was fed with a quantity of food carefully weighed
out for three days, and the quantity of milk, faeces, and urine
emitted during that time was also determined. The food per
day was,
Potatoes, . . 32-418 Ibs. avoirdupois.
Hay (2d crop) . 16-535
Water, . . 132-282
It was necessary to determine ho\v much water the food contain-
ed. It was found to be as follows :
Dry. Water.
The potatoes consisted of, 9-08 Ibs. + 23-368 Ibs.
The hay of, . . 14-22 + 2-315
Water, . . . 23-30 25-683
132-282
157-965
So that the dry portion of the food was 23-3 Ibs., and the water
157-965 Ibs.
The weight*of the milk, urine, and faeces was as follows :—
* Ann. de Chim. et de Phys. Ixxi. 113 and 128.
RESPIRATION.
Milk,
Urine,
Faeces,
Dry.
18-7 Ibs. composed of 2-54 Ibs. -f
18-13 . . 2-12 +
62-63 . . 8-819 +
Water.
16-16
16-01
54-81
86-98
Total, 13-479
Specific gravity of milk, . . 1*035
Specific gravity of urine, . . 1 -034
All of these dry substances were subjected to an ultimate analy-
sis, and found composed as follows : —
Potatoes. Hay. Milk.
Ibs. Ibs. Ibs.
1-387
0-218
0-102
0-709
0-124
Carbon,
4-004
6-698
Hydrogen,
0-527
0-796
Azote,
0-109
0-341
Oxygen,
3-986
4-963
Salts and earth,
0454
1-422
Urine.
Ibs.
0-578
Faeces
Ibs.
3-774
Total Total in
food, dejecs.
10-702 5-739
0-055
0-458
1-323
0-731
0-080
0-203
0-450
0-385
0549
3-325
8-949
4-583
0-849
1-058
9-08 14-22 2-54 2-111 8-818
The cow neither gained nor lost in weight during the experi-
ment. The carbon taken in exceeded that in the dejections by
nearly 5 Ibs. Therefore 5 Ibs. of carbon must have been dis-
charged by respiration and transpiration , The hydrogen taken
in exceeded that in the dejections by nearly half a pound, which
must have been thrown out in the form of water by respiration
or transpiration. The difference in the quantity of azote taken
in and given out is so small that it may be only an error in the
experiment. But, as the quantity taken in is rather greater than
that given out, we have no reason to conclude that azote is ab-
sorbed by the lungs.
Boussingault made a similar experiment on a horse for three
days, during which he neither gained nor lost weight. The food
per day was,
Hay, .
Oats,
Water, .
The dejections per day were,
Urine,
Fasces,
16-54 Ibs.
4-87
266-11
2-928 Ibs. sp. gr. 1-064
3-45
The composition of food and dejections,
624
FUNCTIONS OF ANIMALS.
Hay,
Oats,
Dry.
14-26 Ibs.
+
-f
Urine,
Faeces,
Dry.
0-339 Ibs.
778
+
8-119
Water.
2-28 Ibs.
0-73
266-11
269-12
Water.
2-589 Ibs.
23-67
26-259
The ultimate analysis gave,
Carbon,
Hydrogen,
Azote,
Oxygen,
Ashes,
Hay.
Ibs.
6-531 .
Oats.
Ibs.
2-099
Urine.
Ibs.
. 0-121
Faeces.
Ibs.
. 3-001
Total Total de-
food, jections.
. 8-630 . 3-122
0-713 .
0-265
. 0-013
. 0-397
. 0-798 .
0-410
0214 .
0-091
; 0-042
. 0-171
. 0-305 .
0-213
5-518 .
1-519
. 0-038
. 2-933
. 7-037 .
2-971
1-283 .
0-166
. 0-123
. 1-268
. 1-449 .
1-391
14-259 4-140 0-337 7-77 18-219 8-107
The very same inferences may be drawn from this experiment
as from that of the cow. A good deal of the carbon and hydro-
gen must escape by the lungs and skin. The azote thrown out
is rather less than that in the food, but the difference is so small
that it may be owing to errors in the experiment The water
taken into the stomach of the
Cow, . . 157-965 Ibs. Given out 36-98 Ibs.
Horse, . . 266-11 26-259
Hence, in twenty-four hours the quantity of water given out by
respiration and transpiration must have been in the
Cow, . . 120-985 Ibs.
Horse, . • . 239-86
This is a much greater quantity than we were prepared to ex-
pect.
Dr Goodwyn has shown very clearly that black blood does not
stimulate the heart to contract ; but that red blood does.*
The blood is a fluid of so complex a nature that it is not easy
to ascertain the changes produced in it by exposure to different
gases out of the body ; and even if that could be done, we have
See the fourth section of his work on the Connection of Life with Respiration.
RESPIRATION. 625
no method of proving that the effects of these gaseous bodies up-
on the coagulated blood are the same as they would be on the
blood in its natural state, circulating in the vessels of a living
animal. The facts which have been ascertained are the follow-
ing :
1st. It appears from the experiments of Priestley, Girtanner,
and Hassenfratz, that when venous blood is exposed to oxygen
gas confined over it, the blood instantly assumes a scarlet colour.
Davy could not perceive any sensible diminution of the bulk of
the gas.
2d. The same change of colour takes place when blood is ex-
posed to common air. In this case a quantity of carbonic acid
gas is formed, and a quantity of oxygen gas, exactly equal to it
in bulk, disappears ; making allowance for the small quantity of
carbonic acid, which we may suppose to be absorbed by the blood
itself.
3d. Venous blood exposed to the action of azotic gas conti-
nues unaltered in colour ; neither does any perceptible diminu-
tion of the gas ensue.
4th. Venous blood exposed to the action of nitrous gas be-
comes of a deep purple, and about one-eighth of the gas is ab-
sorbed.
5th. Venous blood exposed to nitrous oxide becomes of a
brighter purple, especially on the surface, and a considerable
portion of the gas is absorbed.
6th. Venous blood exposed to carbonic acid gas becomes of a
brownish-red colour, much darker than usual, and the gas is
slightly diminished in bulk.
7th. Carburetted hydrogen gas gives venous blood a fine red
colour, a shade darker than oxygen gas does, as was first observ-
ed by Dr Beddoes, and at the same time a small portion of the
gas is absorbed. This gas has the property of preventing, or at
least greatly retarding the putrefaction of blood, as was first ob-
served .by Mr Watt*
8th. When arterial blood is put in contact with azotic gas, or
carbonic acid gas, it gradually assumes the dark colour of venous
blood, as Dr Priestley found.f The same philosopher also ob-
served, that arterial blood acquired the colour of venous blood
when placed in vacuo.\ Consequently this alteration of colour
* Davy's Researches, p. 380. f Priestley, iii. 363.
\ Priestley, iii. 363, and Ann. de Chim. ix. 269.
R r
626 FUNCTIONS OF ANIMALS.
is owing to some change which takes place in the blood itself, in-
dependent of any external agent.
The arterial blood becomes much more rapidly and deeply
dark coloured when it is left in contact with hydrogen gas placed
above it.* We must suppose, therefore, that the presence of this
gas accelerates and increases the change, which would have taken
place upon the blood without any external agent.
9th. If arterial blood be left in contact with oxygen gas, it
gradually assumes the same dark colour which it would have ac-
quired in vacuo, or in contact with hydrogen ; and after this
change oxygen can no longer restore its scarlet colour.f There-
fore it is only upon a part of the blood that the oxygen acts ;
and after this part has undergone the change which occasions
the dark colour, the blood loses the power of being affected by
oxygen.
1 Oth. Mr Hassenfratz poured into venous blood a quantity of
chlorine ; the blood was instantly decomposed, and assumed a
deep and almost black colour. When he poured common mu-
riatic acid into blood, the colour was not altered.^
11 tli. But one of the great purposes which respiration serves is
the evolution of heat. The temperature of all animals depends
upon it. It has been long known that those animals which do
not breathe have a temperature but very little superior to the me-
dium in which they live. This is the case with fishes and many
insects. Man, on the contrary, and quadrupeds, which breathe,
have a temperature considerably higher than the atmosphere :
that of man is 98°. Birds, which breathe in proportion a still
greater quantity of air than man, have a temperature equal to
103° or 104°.
Before attempting to give a theory of animal heat, it may be
worth while to state the most important facts that have been as-
certained respecting the temperature of man and the inferior
animals.
The internal temperature of an adult man in a temperate cli-
mate is about 98°. When he passes from a cold to a hot cli-
mate his temperature rises to 98^° or even to 101°. In general
the heat under the tongue is 98°, and that in the arm-pit 97° or
96^°. But Deluc assures us that, if a thermometer be kept an
hour in the arm-pit, it rises to 98°. There seems no difference
in the mean temperature of the different races of men.
* Fourcroy, Ibid. vii. p. 149. f Ibid. ix. p. 268. \ Ibid.
HKSPI RATION.
The human body does not seem capable of bearing exposure
to a cold of 17°.5, unless counteracted by active motion, without
losing the sensibility and the life of the part thus exposed. Nor
can it bear long exposure to a heat of 97°, without pernicious
effects. Lemonnier staid half an hour each day for twenty -eight
days in a bath, heated to 100° without inconvenience. He then
went into a bath of 112°. In six minutes sweat ran down his
face, and his body was red and swelled. After seven minutes he
was in a violent agitation, the pulse quick and strong, and dur-
ing the eighth minute he was attacked by giddiness, which ob-
liged him to come out of the bath.* Dr Berger could bear a
bath of 108° only for ten minutes. His pulse rose from 80 to
112. Berger and Delaroche suffered little from ten minutes
continuance in a dry stove heated to 175°, and from thirteen mi-
nutes continuance in a vapour bath of 102J°.f
The experiments of Dr Fordyce, Dr Blagden, Sir Joseph
Banks, &c. in 1775 are well-known. They went into a room
heated to 260°, and staid in it for a considerable time without
inconvenience. From some of their experiments, particularly
those of Dr Fordyce, in which the room was heated by the va-
pour of water, it would seem to follow that the human body in
certain circumstances, has the power of generating cold4
The heat of new-born children is higher than that of adults,
being 98°.5 or 99°. According to the observations of John Hun-
ter the heat, when we are asleep, is less than when we are awake.
Dr John Davy made a set of observations on the temperature
of various parts of his body in the morning when coming out of
bed, which it may be worth while to state :
Middle of the sole of the foot, . 90°
Heel under the tendo Achillis, . 93
Shin bone, . ^ • . . 91 J
Calf of the leg, . . . 93
Ham, ... 95
.. Above the artery of the thigh, . 94
Middle of the rectus muscle of the thigh, 91
Groin, .... 96-5
Quarter of an inch above the navel, . 95
Above the 6th left rib, . . 94
Above the 6th right rib, . . 93
* Berger; Memoires de la Societe de Physique et d'Hist. Naturelle de Ge-
neve, vi. p. 320.
f Ibid. p. 326. \ Phil. Trans. 1785, pp. Ill, 484.
628 FUNCTIONS OF ANIMALS.
Dr Davy ascertained also that arterial blood in a healthy ani-
mal is 1° or 1°.5 hotter than venous blood.
The following observations were made on a female :
Heat in the female bladder, . . 101^°
,,. vagina, * •>•"•;•' 101
rectum, . • * ;. . 100 J
mouth, . .,* 99
arm-pit, . . . 97e61
According to Dr Berger, when an animal is in a dormant state,
it loses three-fourths of its natural heat, reckoning from 32°. *
In asphyxia, syncope, gangrene, and sphacelus, the heat of the
body diminishes. During a pleurisy in Minorca the heat of the
patient was from 102° to 104°.f A soldier at Colchester, while
ill of the Walcheren intermittent fever, had his skin of the tem-
perature 102°. But after the affusion of cold water it sunk to
97°. The headach disappeared, and a gentle moisture came
out on the skin.} In intermittents, according to Schwenkie, the
heat of the skin varies from 100° to 108°,§ while De Haen states
the heat in continued fevers to be as high as 109°. [| Dr Currie
states from his own observations that in scarlatina the heat of the
skin varies from 106° to 112°.1F While, according to Chisholm,
it varies in inflammatory fever from 99° to 112°.** Dr Berger
states the heat of an abscess in the thigh at 100°ff
Such are the most important facts which have been ascertain-
ed respecting the heat of the human body in health and disease.
I shall now state the temperatures of various inferior animals, as
they have been collected by the industry of Dr Berger.} t
Apes. Young tiger, 99°.
Simia Aygula (arm-pit), 1 04C.5 and Jackal, 101°.
101°. John Davy. Bat, 100° to 101°.
Callitriche (rectum), 96°. Viverra Monzos, 103°.
Dog aged three months, 103°.064.§§
Carnivorous Quadrupeds. An adult male cat, 103°.604.|| |J
Mean heat of these animals,
103°.25. Gnawers.
Cat, 101° to 102°. Pulse, 100. Mean heat, 102°.4.
Panther, 102°. Rabbit, 99°.5.
* Memoires de la Societe de Physique, et d'Hist. Nat. de Geneve, vii. 310.
f Edin. Essays, ii. Art. 29. J Berger, Ibid. p. 314.
§ Haller, Elem. Phys. ii. 36. || Haller, Ibid.
1 Reports, ii. 428. ** Berger, ubi autem, p. 313. ft Ibid. p. 317.
J{ Mem. de la Societe de Phys. et de'Hist. Nat. de Geneve, vi. 310.
$§ Despretz, Ann. de Chim. et de Phys. xxvi. 338.
tin
RESPIRATION,
629
Cabiais, 102*. Pulse, 140.
Guinea pig, 101°.4.
Adult guinea pig, 96°.368. *
Squirrel, 102°.
Rat, 102°.
Mouse, 99.
Marmot, when lively, 101°. When
torpid, 67°, or even as low as
Pachydermata.
Elephant, 99°.5.
Sow, 104° to 107°.f
Boar, 104°.
Ruminantia.
Elk, 103°.
Chamois, 105°. In vagina, 104°. 75.
Ox, 101° to 103.°
Calf 103° to 105°. In vagina,
101°.75, 104°.
Goat, 104°.
Sheep, 104° to 105°4 In vagina,
105°, 104°.33.
Lambs, 106°.
Cow with calf, in vagina, 102°.75.
Solipedes.
Horse, 100°.4 to 103°.§
Ass, 97° to 99°.5.
Cetacea.
Porpois, 100°.
Meanofcetacea, 101°.5.
Mean heat of Quadrupeds
Monkeys, . 99°.7
Carnivore us quadrupeds, 103°.264
Gnawers, . 101°.939
Pachydermata, . 105°.23l
Ruminantia, . 104°.029
Solipedes, . 99°.644
Amphibia and cetacea, 10l°.5
If we reckon the number of respirations in these animals 1,
the beats of the pulse will be 3 J, or there are 3^ beats of the
pulse for every respiration.
frequenting
Birds of Prey.
Mean heat, 104°.528.
Pica?, 106°.689.
Water fowl, 108°.361.
Herons and birds
marshes, 107°.194.
Domestic fowls, 107°.24.
Passeres, I09°.7l.
The following temperature of birds was determined by M.
Despretz : ||
Two adult ravens, 109°.238
Four young owls (flying
well), . . 105°.638
An adult owl, . 106°.646
An adult falcon, . 106°.646
Three pigeons, . 109°.346
Three young sparrows, 102°.344
An old sparrow, . 107°.
Ditto, older, . 107°. 528
An old yellow hammer, 109°. 184
Two young crows, . 106°. 166
Frogs and Sea Tortoises.
They have a temperature of about
5° above that of the air in which
they live. Sir A. Carlisle found
a frog 8° higher than the air.lT
Reptiles.
Testudo midas, 84° to 85°.
geometrica, 62°.5.
Testudo lateria, 54° to 65°.
Rana ventricosa, 77°.
Frogs, 3°.7 above the air.
Toad, 44°, the air being 33°.
Crocodile, 60°. Air, 37°.TV-
Lacerta agilis, 71°. Air, 63°.5.
Green lizzard, 68°. Air, 68°. 5.
Proteus anguinus, same a« that of
the air.
* Despretz, Ann. de Chim. et de Phys. xxvi. 338.
t Carlisle, Phil. Trans. 1805, p. 22. \ Ibid
|| Ann. de Chim. et de Phys. xxvi. 338
f Phil. Trans. 1805, p. 22.
§ Ibid.
630 FUNCTIONS OF ANIMALS.
Serpents. Insects.
Viper, 68°. Air, 58°. John Hun- Caterpillars have a higher tem-
ter. perature than the same insects
Green serpent, 88°. Air, 81°.5. in the state of butterfly or chry-
salis. §
Fish. Bee-hive, 88°. John Hunter.
About 0°.85 above that of the wa- Snails (Helix pomatia), 57°.66.
ter in which they live. Air, 550.4.
Two carps, 53 '042 * Oyster, 82° on the sea- shore Cey-
Two tenches, . 52'772f Ion.
Water in which these fish Leech, same as that of the me-
lived, . 51-494J dium.
Within these few years very delicate experiments have been
made by Becquerel, Breschet, &c. upon the temperature of dif-
ferent internal parts of the body by means of thermo-electricity.
Two wires of different metals are soldered together and con-
nected with a magneto-electric multiplier. The extremities of
these wires are plunged into the part of the body whose tempe-
rature is wanted, the deviation of the needle marked, and water
heated till it produce the same deviation. It is obvious that the
internal part of the body experimented upon has in this case the
same temperature as that of the water. The following tables
exhibit the result of a set of experiments made by MM, Becque-
rel and Breschet upon three individuals distinguished by the let-
ters A, B, and C. A and B were 20 years of age each, while C
was 25. ||
First series of experiments. Temperature of air 53°.
Biceps of the arm of A, 97°.75 Black dog.
Adjacent cellular tissue, 94 '46 Flexor muscle of thigh, . 101°. 12
Mouth, . • 98-24 Cellular tissue of neck, . 98 -60
Biceps of the arm of B, 98-29 Abdomen, . . 101 '30
Adjacent cellular tissue, 95 -81 Thorax, . 4 .' 101 -12
Mouth, . . 98 -06
Biceps of C, . 98-186 Another dog.
Cellular tissue, . 95 -63 Muscle of thigh, . 100°. 40
Mouth, . . 98 -60 Thorax, . . 98 -60
Abdomen, . . 100 -58
Second series of experiments. Temperature of air 53°.
Biceps muscle of B, . 89°.294 Cellular tissue, ^J . / • 95°.954
Cellular tissue, •". • 96 044
Calf of leg, ..::-; 98-42 Black dog.
Mouth, . <U,Lrt 98-60 Muscle of thigh, . 101°-48
Biceps of C, . 98 '42
Third series of experiments.
Mouth of B, . 98°. 33 Cellular tissue, . 95°. 864
Mouth of A, . 98-51 Carp ( Cipr'mus carpio'), . 56.30
Mouth of B, . 98 -60 Water, . , 55 .40
Biceps of B, 98 -78
• Despretz, Ann. de Chim. et de Phys. xxvi. 338. f Ibid. \ Ibid.
Ibid. li Becquerel, Traitc de 1' Electric-it e, iv. p. 17.
RESPIRATION. 631
Fourth series of experiments.
Poodle dog. Thorax, . . 101°. 93
Muscle of thigh, . 100°.8o Brain, . . 101 -93
Becquerel found that when the muscles were made to contract,
their temperature was increased about 0°.9. If while the wire
is in the biceps muscle of the arm, the individual experimented
on saws a piece of wood for about five minutes with that arm,
the temperature increases about 1°.8. Agitation, motion, and in
general every thing which occasions an afflux of blood has a
tendency to raise the temperature of a muscle. When an ar-
tery going to a muscle is compressed so as to diminish the flow
of blood to it, the temperature of the muscle sinks.
12. Ever since the publication of Mayow's tracts, or at least
ever since the speculations of Dr Black on heat, became known
to chemists, it has been the general opinion of physiologists that
animal heat is generated by respiration. And in the year 1777, the
theory of Dr Black, respecting latent and specific heat, was ap-
plied to the explanation of respiration by Dr Adair Crawford.
The experiments on the specific heat of the gases, upon which
Dr Crawford's Theory of Animal Heat is founded, were repeat-
ed by him again in London, with greater care and with a better
apparatus, and the errors into which he had fallen, (which, how-
ever, did not affect his theory,) were corrected in the second edi-
tion of his work, published in 1788.
Dr Crawford's theory of animal heat was generally adopted
by physiologists till the publication in 1812 of Sir Benjamin
Brodie's very curious and important experiments on the influ-
ence of the brain in the production of animal heat.* These ex-
periments show that the action of the brain or the nervous energy
has considerable influence on the production of animal heat. He
considered it as proved, that the volume of air was not altered
by respiration, and that no other change took place in it except
the substitution of carbonic acid gas for an equal volume of oxy-
gen gas which had disappeared. His experiments were made upon
rabbits.
(1.) A rabbit whose volume was 50 cubic inches in thirty mi-
nutes converted 25'3 cubic inches of oxygen gas into carbonic
acid.
(2.) A rabbit of the volume 48 cubic inches in thirty minutes
converted 28 -22 cubic inches of oxygen into carbonic acid.
* Phil, Trans. 1812, p. 378.
FUNCTIONS OF ANIMALS.
(3.) A rabbit of the volume 48 cubic inches, in thirty minutes
converted 28-22 cubic inches of oxygen into carbonic acid.
The mean of these three experiments gives the consumption
of oxygen gas by the respiration of a rabbit, to amount to 27*25
cubic inches, or at the rate of 54^ cubic inches in the hour.
Now, it has been stated above that the mean quantity of carbo-
nic acid gas formed by the respiration of a man in an hour is
373-24 cubic inches, which is almost seven times greater than
the quantity formed by the respiration of the rabbit. The ave-
rage specific gravity often men tried by Mr Robertson was 0-89,
and the average weight of each 145*9 Ibs. or 4545 cubic inches,*
or more than ninety-two times the bulk. Thus, it appears, (sup-
posing Brodie's experiments to approach accuracy,) that the
quantity of carbonic acid formed by the respiration of the rab-
bit is more than ten times as great (making allowance for the
difference of bulk) as in man.
(1.) Mr Brodie having procured two rabbits of the same size
and colour, divided the spinal marrow in the upper part of the
neck of one of them. An opening was made in the trachea by
means of which artificial breathing was kept up for half an hour.
The heat of the rectum at the commencement of the experiment
was 97°, at its termination 90°. The carbonic acid gas formed
was 20-24 cubic inches, or about one-fourth less than in the liv-
ing rabbit. The second rabbit killed at the same time, and in
the same way, was placed in the same circumstances with the
first, but without artificial respiration. At the end of the half
hour, the thermometer in its rectum stood at 91°.
(2. ) Two rabbits were killed by inoculation with woorara poi-
son. In the first the lungs were inflated by artificial inspiration
for half an hour. The thermometer in the rectum sunk from
98° to 91°. The carbonic acid formed was 25-55 cubic inches,
or only one-sixteenth less than the normal quantity. The second
rabbit was placed in exactly the same circumstances, but without
artificial respiration. In half an hour, the thermometer in the
rectum sunk to 92°.
(3.) Two rabbits were killed by woorara. In one the respira-
tion was kept up artificially for thirty-five minutes. The ther-
mometer in the rectum sunk from 97° to 90°. The carbonic
acid formed was 31-75 cubic inches, which is at the rate of
* Phil. Trans. 1757, p. 30.
RESPIRATION. 633
2 7 '2 2 cubic inches in half an hour, or almost exactly the nor-
mal quantity. The second rabbit was placed in exactly the same
circumstances, but without artificial respiration. The thermo-
meter in the rectum sunk in thirty-five minutes to 90°5.
(4.) The experiment was repeated on another rabbit killed by
the essential oil of bitter almonds. In half an hour, the ther-
mometer in the rectum sunk to 90°. The carbonic acid evolved
during the artificial respiration was 28-275 cubic inches, or some-
what more than the normal quantity.
If the accuracy of these experiments may be depended on, it
seems to follow from them, that the chemical changes going on
in the lungs are not the source of the heat of the animal. But
it must not be concealed that they were repeated and varied by
M. Legallois, who obtained different results. He found, in most
cases, that when artificial respiration is kept up in a dead ani-
mal, the animal heat continues higher than when the lungs are
not inflated. The result of his experiments was, that in general
the heat of animals is directly proportional to the quantity of
oxygen which they consume in a given time.*
The experiments of Legallois agree well with those of Des-
pretz,f which are the most elaborate hitherto made upon respi-
ration, and of which I shall now proceed to give an account.
13. According to Dr Black, part of the latent heat of the air
inspired becomes sensible ; and of course the temperature of the
lungs, and the blood that passes through them, must be raised ;
and the blood thus heated, communicates its heat to the whole
body. This opinion was ingenious, but it was liable to an un-
answerable objection : for if it were true, the temperature of the
body ought to be greatest in the lungs, and to diminish gradual-
ly as the distance from the lungs increases, which is not true.
The theory, in consequence, was abandoned even by Dr Black
himself, at least he made no attempt to support it.
Dr Crawford, who considered all the changes operated by res-
piration as taking place in the lungs, accounted for the origin of
the animal heat almost precisely in the same way with Dr Black.
According to him, the oxygen gas of the air combines in the
lungs with the carbon emitted by the blood. During this com-
bination, the oxygen gives out a great quantity of caloric, with
• Ann de Chim et de Phys. xxvi. 342.
t Ibid xxvi. 337.
634" FUNCTIONS OF ANIMALS.
which it had been combined ; and this caloric is not only suffi-
cient to support the temperature of the body, but also to carry off
the new-formed water in the state of vapour, and to raise consi-
derably the temperature of the air inspired. According to this
philosopher, then, the whole of the caloric which supports the
temperature of the body is evolved in the lungs. His theory ac-
cordingly was liable to the same objection with Dr Black's ; but
Dr Crawford obviated it in the following manner : He found
that the specific caloric of arterial blood was 1-0300, while that
of venous blood was only 0-8928. Hence, he concluded, that the
instant venous blood is changed into arterial blood, its specific
caloric increases ; consequently it requires an additional quan-
tity of caloric to keep its temperature as high as it had been
while venous blood. This addition is so great, that the whole
new caloric evolved is employed : therefore, the temperature of
the lungs must necessarily remain the same as that of the rest of
the body. During the circulation, arterial blood is gradually
converted into venous ; consequently, its specific caloric dimi-
nishes, and it must give out heat. This is the reason that the
temperature of the extreme parts of the body does not diminish.
Lavoisier, who was the first person that ascertained the com-
position of carbonic acid gas, considered the phenomena of res-
piration as analogous to combustion. Now, when oxygen com-
bines rapidly with carbon or hydrogen, combustion takes place
and heat is evolved. The evolution of heat in the lungs by the
combination of the carbon of the blood with the oxygen of the
atmosphere is analogous to combustion.
(1.) It follows, from the experiments of M. Despretz, that du-
ring the combustion of an avoirdupois pound of carbon, the
quantity of heat evolved is sufficient to melt 104*2 Ibs. of ice.
Now, if the latent heat of water be 140°, 104-2 Ibs. of ice will
require to melt 14,588 degrees of heat, or, in other words, the
heat evolved during the combustion of a pound of carbon would
heat a pound of water 14,588°.
(2.) The oxygen gas requisite to consume a pound of carbon
amounts to 2| Ibs., which is equivalent to 55,082 cubic inches
at the temperature of 60°. This oxygen gas combines with car-
bon, and is converted into its own volume of carbonic acid gas.
(3.) 55,082 cubic inches of oxygen gas when converted into
carbonic acid gas give out 14,588° of heat; consequently, every
RESPIRATION. 635
3f cubic inches of oxygen gas, when converted into carbonic acid
gas, give out 1° of heat.
(4.) From the experiments of Despretz, it farther appears, that
when a pound of hydrogen is burnt, a quantity of heat is evolv-
ed, capable of melting 315-2 Ibs. of ice, or the heat evolved
would heat one pound of water 44,128 degrees. But for this
combustion eight pounds of oxygen gas are required. Now eight
pounds of oxygen gas are equivalent to 165,246 cubic inches.
Hence every 3 J cubic inches of oxygen gas, when they combine
with hydrogen, evolve 1° of heat. It would appear from this
that the heat evolved during the combustion of carbon and hy-
drogen, is proportional to the quantity of oxygen gas consumed.
These preliminary observations were necessary to enable us to
understand the experiments of Despretz.
(1.) A rabbit was made to breathe during an hour and thirty-
six minutes inclosed in a copper vessel, air-tight, but connected
with two air-holders, by means of which a regular current of air
was made to pass through the vessel. This air, after respiration,
passed through a serpentine worm twelve feet long and surround-
ed with water, which cooled it to the same degree as when ad-
mitted to the vessel containing the animal. The volume of air
respired was 2929 cubic inches. It was reduced by the breath-
ing to 2919-5 cubic inches. The loss of volume was 9-5 cubic
inches, or about s^yth of the original volume. The proportion
of azotic gas was increased by 51*2 cubic inches, The elevation
of temperature of the water gave the quantity of heat withdrawn
from the animal by respiration, &c. 66 Ibs. avoirdupois of water
were heated P.26, or the quantity of heat given out by the ani-
mal in one hour and thirty-five minutes would have elevated the
temperature of one pound of water 70.° 84. The quantity of oxy-
gen gas consumed was 247*5 cubic inches. Of these 187*7 cubic
inches were converted into carbonic acid,* and Despretz supposes
that the other 59-8 cubic inches combined with hydrogen, and
were converted into water.
Now we have stated above that 3 j cubic inches of oxygen
when combined by combustion with carbon or hydrogen would
evolve 1° of heat Hence 247 '5 cubic inches would evolve 66°.
The heat actually given out by the animal was 70° -84, or 4°.&
* This is more than double the quantity of carbonic acid obtained by Sir B,
Brodie in his experiments.
636 FUNCTIONS OF ANIMALS.
more than would have been produced by the quantity of oxygen
gas actually consumed.
(2.) The experiment was repeated with the same rabbit. The
heat given out by the animal during the experiment, being 100°,
that furnished by the oxygen gas converted into carbonic acid
was, . . v .-. 64°.9
By the oxygen which formed water, . 20 -9
Total, . 85 -8
So that 14°. 2 of the heat was due to other processes.
(3.) Six small rabbits fourteen days old were inclosed in the
vessel for two hours and five minutes. The air passed through
the vessel was 3019 cubic inches. It was reduced after the pro-
cess to 2971 cubic inches. So that 48 cubic inches had disap-
peared. The oxygen gas consumed was 254*6 cubic inches, and
the carbonic acid formed amounted to 180-3 cubic inches, so
that 74*3 cubic inches of oxygen must have gone to the forma-
tion of water.
45-9 Ibs. avoirdupois of water were heated 1°.796, or 1 Ib. of
water would have been heated 82° -43.
But the oxygen consumed would have evolved 6 7°. 9, of which
48° is due to the formation of carbonic acid, and 19°. 9 to the
formation of water. The heated evolved exceeds by 14°. 5, what
could have been produced by the formation of carbonic acid and
water.
(4.) A male rabbit evolved 100° heat, of which 68°.3 were
due to the formation of carbonic acid, and 18°.4 to that of water.
The 13°. 3 were in excess.
(5.) Three male guinea pigs were enclosed in the apparatus
for one hour and fifty -four minutes. The air which passed through
the vessel was 2932 cubic inches, the oxygen gas consumed
was 201*32 cubic inches, and the carbonic acid gas formed was
157*93 cubic inches, so that 43*39 cubic inches of oxygen went
to the formation of water.
The air by the process became 2951*8 cubic inches, or the
bulk increased by 19*8 cubic inches.
By the animal heat evolved during the experiment 51*38 Ibs.
avoirdupois of water were heated 1M5. So that one pound
would have been heated 5 9°. 19.
The heat formed during the formation of the carbonic acid
RESPIRATION. 637
was 42°.l, and during the formation of the water 11°.6, making
together 53°.7 ; so that the heat evolved exceeded the heat ge-
nerated by respiration by 5°.4.
(6.) Three female guinea pigs were confined in the apparatus.
Heat evolved 100°, heat due to the formation of carbonic
acid 69°.6, to that of water 19°.3. Both 88*9, or ll°.l less than
the heat evolved by the animal.
(7.) A dog aged five years was put into the apparatus. The ex-
periment lasted one hour and thirty-one minutes. The air which
passed through the vessel containing the dog was 2908*3 cubic
inches ; the volume of this air by the breathing of the dog was
reduced to 2881*2 cubic inches, so that the diminution of vo-
lume was 27' 1 cubic inches, or rather less than 1 per cent.
The oxygen gas consumed was 340*76 cubic inches ; the
carbonic acid formed was 229*94 cubic inches. Hence 110-82
cubic inches of the oxygen must have gone to the formation of
water.
The heat evolved raised the temperature of 55*97 Ibs, avoir-
dupois of water 1°.98. Or it would have raised the tempera-
ture of 1 Ib. of water 110°.8.
The heat evolved by the formation of the carbonic acid is
61°.3, and that by formation of water 29°.56, making together
90°.8, or 20° less than the actual heat evolved.
(8.) A dog of eight months was enclosed in the apparatus for
one hour, forty-two minutes. The volume of air used was 2922*6
cubic inches, reduced by the breathing of the dog to 2885*4 cu-
bic inches. The loss was 37*2 cubic inches, or about 7\th part.
The oxygen consumed was 254*35 cubic inches ; the carbo-
nic acid formed was 169*47 cubic inches, so that 84*88 cubic
inches of the oxygen must have been consumed in forming water.
The heat evolved heated 46 Ibs. avoirdupois of water 1*96,
or it would have raised the temperature of 1 Ib. of water 88°.76.
The heat evolved by the formation of the carbonic acid gas
was 45.°. 19 ; and that by the formation of water 22°.63 ; mak-
ing together 6 7°. 82, or 20°. 94 less than the actual heat evolved.
During' this experiment there were 46*44 cubic inches of azo-
tic gas evolved.
(9.) Two dogs six weeks old were enclosed in the apparatus.
The experiment lasted one hour and forty-two minutes. The vo-
lume of air used was 2871*6 cubic inches. It was reduced by
638 FUNCTIONS OF ANIMALS.
breathing to 2803*5 cubic inches ; so that 68*1 cubic inches, or
about 5*2 d of the whole disappeared during the breathing. The
azotic gas of the air breathed was increased by 66 '94 cubic inches.
The oxygen consumed was 380*37 cubic inches ; the carbo-
nic acid formed was 245*2 cubic inches. Hence 135*17 cubic
inches of the oxygen must have been consumed in the formation
of water.
The heat evolved by the dogs raised the temperature of 56
Ibs. avoirdupois of water 2°.43, or would have raised the heat of
1 Ib. of water 136°.
The heat evolved by the formation of the carbonic acid was
65°. 39, and that by the formation of water 36°.04, making to-
gether 101°.43. This is 34°.57 less than the heat actually
evolved.
(10.) A male cat, more than two years of age, was enclosed in
the apparatus. The experiment lasted one hour and thirty-five
minutes. The quantity of air used was 2922*2 cubic inches.
It was reduced by the breathing of the cat to 2901 cubic inches,
so that the loss of volume was 21*2 cubic inches, or about jy^th
of the original volume. The proportion of azote in the air re-
spired was increased by 3 1*97 cubic inches.
The oxygen consumed was 178*8 cubic inches ; the carbo-
nic acid formed was 125*7 cubic inches ; so that 53*1 cubic in-
ches of the oxygen must have been consumed in the formation
of water.
The heat evolved heated 56 Ibs. avoirdupois of water, 1°.044 ;
or it would have raised the temperature of 1 Ib. of water, 58°.46.
The heat evolved by the formation of the carbonic acid was
33°.52, and that by the formation of water was 14°. 16 ; making
together 47°.68, or 10°.78 less than the heat actually evolved.
(11.) Three adult male pigeons were put into the apparatus.
The experiment lasted one hour and thirty-two minutes. The
volume of air used was 2909*3 cubic inches. It was reduced
by the breathing of the animal to 2907*9 cubic inches. So that
the loss of volume was 1*4 cubic inches, or about ^wth of the
original quantity. The proportion of azotic gas in the air re-
spired was increased by 43*33 cubic inches.
The oxygen gas consumed was 194*4 cubic inches; the car-
bonic acid formed was 149°.5 : so that 44'9 cubic inches of the
oxygen gas must have been consumed in the formation of water.
RESPIRATION. 639
The heat evolved heated 56 Ibs. avoirdupois of water P.159,
or it would have raised the temperature of 1 Ib. of water 64°.9.
The heat evolved by the formation of carbonic acid gas was
3°.87, and that by the formation of water was 11°. 97 ; mak-
ing together 51°.84, or 13°.l less than the heat actually evolved.
(12.) An adult duck was experimented on in the same way.
If we suppose the heat evolved to have been 100°; that result-
ing from the formation of carbonic acid will be 60°.5, and that
from the formation of water 19°.2; making together 79*7, or
20°. 3 less than the heat actually evolved.
(13.) An adult cock was experimented on in the same way. If
we suppose the heat evolved to have been 100° ; that evolved by
the formation of carbonic acid will be 60°.5, and that from the for-
mation of water 19°.2 ; making together 79°, or 20°.3 less
than the heat actually evolved.
(14.) An adult Virginian duck was enclosed in the apparatus.
The experiment lasted one hour and twenty-five minutes. The
volume of air employed was 2937*5 cubic inches, reduced by the
breathing of the animal to 2919*3 cubic inches. The loss of
volume was 18*2 cubic inches, or about TJT of the original vo-
lume. The proportion of azotic gas in the air respired was in-
creased by 44*36 cubic inches.
The oxygen gas consumed was 160*35 cubic inches. The
carbonic acid formed was 97*71 cubic inches ; so that 62*54 cu-
bic inches of the oxygen must have been consumed in forming
water.
The heat given out heated 56 Ibs. of water 0°.99 ; or it would
have raised the temperature of 1 Ib. of water 55°.44.
The heat evolved by the formation of the carbonic acid was
26°.06 ; and that by the formation of water 16°.70 ; making to-
gether 42°. 7 5 ; or 12°. 6 9 less than the heat actually evolved.
(15.) Four owls experimented upon. If the heat given out
was 100°, that evolved by the formation of the carbonic acid was
56°.3, and that by the formation of water 18°.3, making together
74°.6 ; or 25°.4 less than the heat actually evolved.
(16.) 'Four magpies fed on animal food were experimented on.
If the animal heat given out was 100°, that given out by the
formation of carbonic acid was 5 7°. 6, and that by the formation
of water 17°.8; making together 75°.4, or 24°.6 less than the
heat actually evolved.
If these experiments of Despretz have been accurately performed,
640 FUNCTIONS OF ANIMALS.
it follows from them that there is nothing fixed or certain either
in the ratio between the oxygen consumed and the carbonic acid
formed, or in the diminution of volume of the air by breathing ;
or of the heat evolved. In general the more oxygen gas con-
sumed the greater is the quantity of heat evolved ; though this
does not hold rigidly in every experiment.
That the reader may see at a glance the variations in these
experiments, the following table has been calculated, showing the
volume of oxygen consumed, and of carbonic acid formed, the di-
minution of the volume of air breathed, and the heat evolved,
supposing each animal to have breathed ten minutes :
Oxygen con- Carbonic acid Diminutions „
sumed in cu- formed in cu- of bulk of , fd, *
bic inches. bic inches. air.
Man, ;'.;• • . '» , 119' 119* uncertain, uncertain.
Rabbit, .- . . 25-7 19-5 ^ 7°.36
Six small rabbits, . . 20-4 14-4 fa 6 .44
Three male guinea pigs, 17'6 13-8 T^Ff 5.18
A dog, five years old, 37'4 25-2 T£r 12.17
A dog, eight months old, 24-9 16-6 fa 8 .70
Two dogs, six weeks old, 37-3 24-0 ^ 13 .33
A male cat, . 18-9 13-2 T^ 6.15
Three adult male pigeons, 21 -1 16-2 ^£T 7.05
An adult Virginian duck, 18'8 11 '5 T£r 6.52
It follows from these experiments, that the whole animal heat
developed in the living animal is not the consequence of the com-
bination of the oxygen of the atmosphere with carbon and hy-
drogen. If we reckon the animal heat evolved in these experi-
ments 100°, then the portion of it due to the combination of the
oxygen of the atmosphere with carbon and hydrogen during the
circulation of the blood through the body will be 82°.J Conse-
quently, 18°, or almost one-fifth of the whole, must be owing to
other processes not yet sufficiently appreciated. What renders these
conclusions somewhat uncertain, is the great diversity in the ratios
of the heat evolved, and the oxygen consumed in the different ex-
* This column indicates the number of degrees that the temperature of one
pound of water would be heated by the heat given out during ten minutes breathing.
f In this case the bulk of the air was increased by breathing instead of being
diminished.
\ Dr Winn has ascertained that when the elastic coat of an artery is stretch-
ed, heat is evolved (Phil. Mag. (3d series) xiv. 174), and he conceives that this
evolution will supply the surplus heat of the animal above that furnished by res-
piration. Not considering that when the coat contracts it must again absorb
all the heat evolved by the stretching, as was long ago proved to be the case
with caoutchouc by Mr Gough.
RESPIRATION. 641
periments. If we reckon the animal heat evolved to be 100°, t he
quantity of it due to the consumption of oxygen varies in the dif-
ferent experiments from 93°. 1 to 74°.5. This variation will be best
understood if we arrange the experiments in the form of a table :
Heat evolved. ^
Rabbit, . . 100° 93°. 1
Six small rabbits, . . 100 83-58
Three male guinea pigs, . 100 90 -72
A dog, five years old, . 100 81-94
A dog, eight months old, . 100 76-40
Two dogs, six weeks old, . 100 74-57
A male cat, . 100 81 -56
Three adult male pigeons, . 100 79 -87
An adult Virginian duck, „ 100 77 -11
Mean, . . 100 82
To be able to compare the breathing of different animals toge-
ther, as far as the consumption of oxygen is concerned, it would
be necessary to know the weight of the different animals sub-
jected to experiment. This, unfortunately, Despretz has ne-
glected to determine.
Nearly about the time (1823) that Despretz was occupied with
the experiments just detailed, a similar set of experiments was
made by M. Dulong. His method of proceeding was nearly si-
milar to that of Despretz. It will, therefore, be sufficient to state
here the results which he obtained.
His experiments were made upon six kinds of animals, name-
ly, the dog, the cat, the hawk, the cabiai, the rabbit, and the pi-
geon ; and each was several times repeated.
The volume of oxygen consumed by the respiration of the dog,
the cat, and the hawk was a third more than that of the carbonic!
acid gas formed ; and only one-tenth more in the rabbit, the ca-
biai, and the pigeon. Dulong conceives that this difference is
connected with the different kind of food on which these animals live.
More azote is given out during the respiration of herbivorous
animals than of carnivorous. In the former the bulk of the air
expired generally exceeds that of the air inspired.
In carnivorous animals the heat due to the formation of car-
bonic acid gas amounts to 0*49 to 0*55 of the whole heat evolved ;
in frugivorous animals to from 0*65 to 0*75.
If we suppose with Lavoisier and Despretz that the portion of
s s
FUNCTIONS OF ANIMALS*
oxygen which disappears above what can be accounted for by the
formation of carbonic acid gas to the formation of water. Then
from 0*69 to O80 of the whole heat evolved is produced by re-
spiration, and from 0*31 to 0*20 by other and unknown agencies.
I have myself little or no doubt that the whole animal heat
evolved is owing to the conversion of the oxygen gas absorbed
into carbonic acid and water during the circulation. In Des-
pretz's experiments the animals were exposed to a greater cool-
ing agency, from being surrounded by cold water, than in ordi-
nary respiration. If we admit that the great object of respiration
is the generation of heat, and adopt the statement made in this
chapter as accurate, there will be no difficulty in calculating the
average quantity of heat produced in man during twenty-four hours.
The blood in an adult is about 26 Ibs. avoirdupois, and it com-
pletes its circulation through the body in about 3*06 minutes.
Hence, 8^ Ibs. of blood pass through the lungs in a minute.
During each inspiration, 16 cubic inches of air enter the lungs,
and 0*425 Ib. of blood is exposed to its action. During every
inspiration, 0-6432 cubic inch of oxygen gas is absorbed by the
blood ; and as every 4*75 cubic inches of oxygen gas, combin-
ing with carbon or hydrogen, evolved 1 ° of heat, it follows that
the oxygen absorbed during each inspiration evolves (during its
circulation in the blood-vessel) 0-17°, or nearly one-sixth of a de-
gree of heat. The oxygen absorbed during 6 inspirations pro-
duces 1° of heat. Hence, the heat evolved by respiration in
twenty-four hours would heat 1 Ib. of water, 4800°, or, suppos-
ing none of it dissipated, it would heat a middle-sized man 33°
in twenty-four hours.
Those who inhabit cold climates require more heat than those
who live in hot climates. Hence, doubtless, the reason of the
great appetites, and the vast quantity of whale oil swallowed by
the Esquimaux, and the small appetite and vegetable diet of the
inhabitants of the torrid zone.
This subject has been placed in a very clear light by Liebig in
his late work on Animal Chemistry. Respiration, he conceives,
is intended to generate heat, without which no animal could live.
This is effected by the combination of the oxygen of the atmo-
sphere with the carbon and hydrogen of the food. He considers
the unoxygenized portion of food (starch, gum, and sugar) to be
intended for the production of animal heat But it is difficult
ACTION OF THE KIDNEYS. 643
to see how these substances get into the circulation, as no trace
of them can be found in the blood. The heat generated is pro-
portional to the food digested. In hot climates, the waste of heat
being small, but little food is required, whereas in cold climates
the waste of heat is great, and hence the appetite is greatly in-
creased. Liebig conceives that, in consequence of the coldness
of the atmosphere in frigid climates, a greater proportion of oxy-
gen is inhaled than in hot climates ; but as the air inhaled is heat-
ed in the lungs to 98°, and as the azotic gas constitutes four-
fifths of this air, one would expect that the heat necessary to
heat this azotic gas from a very low temperature to 98 p, would
fully compensate for any increase in the density of the oxygen
gas. The number of respirations per minute ought to increase
in cold climates, or, what is more probable, the per centage of
carbonic acid evolved, and of oxygen absorbed during each res-
piration ought to increase.
We want additional experiments. The statement given in
this chapter applies only to the summer. I am not aware of any
attempt to determine the carbonic acid formed by respiration
during winter. It would be interesting to know the per centage
of carbonic acid given out by breathing in India and in St
Petersburg or Stockholm. The subject is well worth the atten-
tion of men of science in India.
CHAPTER III.
OF THE ACTION OF THE KIDNEYS.
A VERY great proportion of blood passes through the kid-
neys ; indeed, we have every reason to conclude that the whole
of the blood passes through them very frequently. These or-
gans separate the urine from the blood, to be afterwards evacua-
ted without being applied to any purpose useful to the animal.
The kidneys are absolutely necessary for the continuance of
the life of the animal ; for it dies speedily when they become by
disease unfit to perform their functions : therefore the change
which they produce in the blood is a change necessary for qua-
lifying it to answer the purposes for which it is intended.
In a preceding chapter of this work, a very minute account
644
FUNCTIONS OF ANIMALS.
has been given of urine, and of the constituents which it con-
tains, and the proportion of each voided from an adult in good
health during the course of twenty -four hours. The following
abstract may be considered as exhibiting an approximation to a
mean :
1. The urea varies from 185-3 grains to 509*3
2. The uric acid, ... 1'373 ... 14-307
3. Fixed salts, ... 378- ...748.
4. Earthy phosphates, 0-447 ... 30-25
5. Common salt, ... 0-247 ... 116-5
6. Sulphuric acid, ... 15-25 ... 57-5
7. Phosphoric acid, 0-17 ... 25-37
It was long believed by physiologists that urea, uric acid,
phosphoric and sulphuric acid were generated in the kidneys by
the peculiar action of these organs. This supposition was found-
ed on the unsuccessful attempts of chemists to detect these substan-
ces in the blood. But MM. Prevost and Dumas showed in
1823, that this opinion was ill founded.* They cut out the
kidneys of dogs, cats, and rabbits. The animals usually died in
about five days after the operation, except the rabbits which did
not live so long. On examining the blood of these animals
drawn a little before death, they succeeded in finding a consider-
able quantity of urea in it. They were not successful in find-
ing phosphoric and sulphuric acid in that blood, but their at-
tempts were made only in a cursory manner. It is evident from
these experiments that the urea in urine is not secreted in the
kidneys but only eliminated. Doubtless this is the case with all
the other peculiar substances found in the urine. The reason
why they cannot be detected in the blood must be, that they are
eliminated by the kidneys as fast as formed ; so that they never
accumulate in the blood in any sensible quantity. Unless when,
by the removal of the kidneys, this removal is prevented.
The kidneys, then, are not organs of secretion but of elimina-
tion. In what organ the urea, uric acid, and other peculiar sub-
stances of the urine are formed, is not yet known. It is probable
that the albumen, fibrin, or hematosin of the blood, undergoes
decomposition in some organ for the formation of some substance
useful in the animal economy, and that the urea and uric acid
are substances formed at the same time, which not being use-
* Ann. de Chim« et de Phys. xxiii. 90.
ACTION OF THE KIDNEYS. 645
ful to the animal economy, are immediately eliminated by the
kidneys.
Professor Liebig, in his late work on Animal Chemistry, p. 136,
has made a remarkable observation. Protein -f 3 atoms water
may be resolved into choleic acid and urate of ammonia.
Protein is, . C48 H36 Az6 Ou
3 atoms water, . H3 O3
Total, . C48 H39 Az6 O17
Choleic acid is, C38 H33 Az O11
Uric acid, . C10 H4 Az4 O6
Ammonia, . H3 Az
Total, . C48 H40 Az6 O17
Differing only by an atom of hydrogen. It would not be sur-
prising, then, if the uric acid and urea as well as the choleic acid
were formed in the liver.
It has been long known that in diseases of the liver the quan-
tity of urea in the urine is diminished. Is it not possible that the
albumen of blood is decomposed into bile and urea ? The urea
and uric acid are rich in azote, while the bile contains but little.
Whether this conjecture be well or ill founded, there can be
little doubt that the formation of these two substances must be
the result of the decomposition of the constituents of blood, to
form some secretion of importance to the animal economy. The
importance of the liver as a secreting organ is obvious from the
great derangement of the system which takes place when it is-
diseased.
Liebig conceives that the matter of bile is absorbed by the
lac teals, and employed in the production of heat by its union
with oxygen during the function of respiration. But certainly
this cannot be the case unless the bile undergoes decomposition.
For in the disease called jaundice, when the bile is absorbed in-
to the system, the skin and eyes are tinged yellow. The me-
thods of determining the quantity of bile secreted are so vague
that no reliance can be placed on them.
Chossat has shown that the quantity of solid matter in the
urine increases with the food, and is proportional to it, supposing
the whole food to be digested.
646 FUNCTIONS OF ANIMALS.
When a person is fed on bread the quantity of solid urine
voided is less than when he is fed on eggs, and when he is fed
on eggs less than when fed on meal. The ratios are nearly
5:7: 9.*
The quantity of solid matter in the urine is proportional to
that of azote in the food.f
Ounces. Grains.
Food, . 82 77
Urine, . 56 64
Difference, 26 13
When the food is egg | °ths of the azote of the food found in
the urine ; but \ |ths of the carbon is wanting, because it is given
off by the lungs.
The person fed on one meal a day, generous and copious.
First experiment lasted 32 days ; second, 35 days.
Mean urine rendered daily in 24 hours, dividing the day into
6 periods of 4 hours each :
1st Series. 2d Series. 3d Series. 4th Series.
Mean urine. Mean urine.
Solid. Solid.
1st period, from 2 to 6 P. M., 55'3 gr. 61-4>gr. 107 | oq.H
2d do. from 6 to 10 p. M., 88-7 102-8 J
3d do. from 10 p. M. to 2 A. M., 107-9 218-9 ) OAQ 7 OK Q
4th do. from 2 to 6 A. M., 85-6 106-3 }
5th do. from 6 to 10 A. M., 100-1 77-2) on.o Qn o
6th do. from 10 A.M. _to 2 p. M., 70-4 77-2 J
Total, . 508- 643-8 617-0 100-0
The quantity of food in the second series was greater ; the
kind the same. It is presumed that the food was taken just
before the beginning of the first period.
The greatest quantity is from 8 to 12 hours after food ; the
least just after taking food.
In the fourth series the food was much diminished and of infe-
rior quality.
The secretion of solid urine is at a minimum the first two hours
after taking food, increases much the next two hours, and main-
tains nearly the same rate during the next four hours.
When food was only taken once in 48 hours there was a feel-
ing of cold the second day.
* Jour, de Phys. v. 84. f Ibid. p. 86.
ACTION OF THE KIDNEYS.
647
Food only taken once in 48 hours. The food was vegeto-
albuminous, drink tea. Quantity double of that taken once in
24 hours. Time of eating, the end of the first of the 6 periods
of 8 hours each. Experiment lasted 16 days.
Solid urine.
1st period 8 hours,
2d do. 8 to 16 hours,
do. 18 to 24 do.
do. 24 to 32 do.
3d
4th
5th
6th
do. 32 to 40
do. 40 to 48
do.
do.
112-1
141-6
90-8
111-9
84-5
54-7
595-6
Two repasts a day, food vegeto-animal, the first at 9 A. M., the
second the most abundant at 5 P. M. Periods of 6 hours each,
commence with it
Solid urine. Solid urine.
1st period,
2d do.
3d do.
100-5
110-3
107-1
Three meals a day.
and 9 P. M.
317-9
Food the same.
1st period, 7 A. M. to 3 p. M.,
2d do. 3 P. M. to 11 P. M.,
3d do. 11 P. M. to 7 A. M.,
151-1
196-1
165-9
513-1
At 8 A. M., 1 P M.,
Solid urine.
142-1 grains
158-6
94-2
394-9
By a cold bath (8 2°. 7 6), the aqueous portion of the urine is
sextupled, by a warm bath (99°), not increased, pulse 132. In
the cold bath the pulse became slower, sinking at last (in two
houfs) to 40 in a minute, from 60. The solid part of urine is
also increased in the cold bath by the increase of the watery
portion.
The quantity of solid urine diminishes in the evening when
the nervous energy is diminished, and requires to be restored by
sleep.
The secretion of solid urine is a little increased by sleep, about
648 FUNCTIONS OF ANIMALS.
when the strength is unimpaired, and also when enfeebled by
scanty food.
i
295
CHAPTER IV.
OF PERSPIRATION.
IT is well known that considerable quantities of matter in the
state of vapour are constantly emitted from the skin. This va-
pour is called perspirable matter or perspiration. When, by the
sudden application of cold, the exhalents by which this va-
pour is thrown out are shut, the system becomes deranged,
and what we call in common language a cold is the conse-
quence. All the facts respecting the quantity and nature of
this perspired matter at present known have been stated under
the title of perspiration and sweat in a preceding chapter of this
work, to which the reader is referred. Nothing is known re-
specting the nature of the process. The exhalent vessels are
situated in the skin, and, according to modern anatomists, are
twisted in the form of a cork-screw. They are exceedingly small
in diameter, and their open mouths terminate just under the epi-
dermis. The process of perspiration is very similar to respira-
tion. Whether the external air has any thing to do with it has
not been ascertained ; but it is probable that it has. Water, car-
bonic acid, lactic acid, and an oily matter having a peculiar
smell, are thrown out from the blood-vessels of the skin, and
doubtless in considerable quantity.
It has been supposed that the skin has the property of absorb-
ing moisture from the air, but this opinion has not been confirm-
ed by experiments, but rather the contrary.
The chief arguments in favour of absorption of the skin have
been drawn from the quantity of moisture discharged by urine,
being, in some cases, not only greater than the whole drink of
the patient, but even than the whole of his drink and food. But
it ought to be remembered that, in diabetes, the disease here al-
luded to, the weight of the body is continually diminishing, and
therefore part of it must be constantly thrown off. Besides, it is
scarcely possible in that disease to get an accurate account of the
food swallowed by the patients ; and in those cases where very
PERSPIRATION. 649
accurate accounts have beeiv kept, and where deception was not
so much practised, the urine was found not to exceed the quan-
tity of drink.* In a case of diabetes, related with much accu-
racy by Dr Gerard, the patient was bathed regularly during the
early part of the disease in warm water, and afterwards in cold
water : he was weighed before and after bathing, and no sensi-
ble difference was ever found in his weight.f Consequently, in
that case, the quantity absorbed, if any, must have been very
small.
It is well known that thirst is much alleviated by cold bathing.
By this plan Captain Bligh kept his men cool and in good health
during their very extraordinary voyage across the South Sea.
This has been considered as owing to the absorption of water by
the skin. But Dr Currie had a patient who was wasting fast
for want of nourishment, a tumour in the oesophagus preventing
the possibility of taking food, and whose thirst was always alle-
viated by bathing ; yet no sensible increase of weight, but rather
the contrary, was perceived after bathing. It does not appear,
then, that in either of these cases water was absorbed.
Farther, Seguin has shown that the skin does not absorb
water during bathing, by a still more complete experiment : He
dissolved some mercurial salt in water, and found that the mer-
cury produced no effect upon a person that bathed in the water,
provided no part of the cuticle was injured : but upon rubbino-
off a portion of the cuticle, the mercurial solution was absorbed
and the effects of the mercury became evident upon the body!
Hence it follows irresistibly, that water, at least in the state of
water, is not absorbed by the skin when the body is plunged into
it, unless the cuticle be first removed.
This may perhaps be considered as a complete proof that no
such thing as absorption is performed by the skin ; and that there-
fore the appearance of carbonic acid gas, which takes place when
air is confined around the skin, must be owing to the emission of
carbon. But it ought to be considered, that, although the skin
cannot absorb water, this is no proof that it cannot absorb other
substances ; particularly that it cannot absorb oxygen gas, which
is very different from water. It is well known that water will
not pass through bladders, at least for some time : yet Dr Priest-
ley found that venous blood acquired the colour of arterial blood
* See Rollo on Diabetes. f Ibid . ii. 73.
650 FUNCTIONS OF ANIMALS.
from oxygen gas, as readily when these substances were separat-
ed by a bladder as when they were in actual contact. He found,
too, that when gases were confined in bladders, they gradually
lost their properties. It is clear from these facts, that oxygen
gas can pervade bladders : and if it can pervade them, why may
it not also pervade the cuticle ? Nay, farther, we know from the
experiments of Cruickshanks, that the vapour perspired passes
through leather, even when prepared so as to keep out moisture,
at least for a certain time. It is possible, then, that water, when
in the state of vapour, or when dissolved in air, may be absorb-
ed, although water, while in the state of water, may be incapable
of pervading the cuticle. The experiments, therefore, which
have hitherto been made upon the absorption of the skin are in-
sufficient to prove that air and vapour cannot pervade the cuti-
cle, provided there be any facts to render the contrary supposi-
tion probable.
Now, that there are such facts cannot be denied. I shall not
indeed produce the experiment of Van Mons as a fact of that
kind, because it is liable to objections, and at best is very indeci-
sive. Having a patient under his care who, from a wound in the
throat, was incapable for several days of taking any nourishment,
he kept him alive during that time by applying to the skin, in
different parts of the body, several times a day, a sponge dipped
in wine or strong soup.* A fact mentioned by Dr Watson is
much more important, and much more decisive. A lad at New-
market, who had been almost starved in order to bring him down
to such a weight as would qualify him for running a horse race,
was weighed in the morning of the race day ; he was weighed
again an hour after, and was found to have gained 30 ounces of
weight ; yet in the interval he had only taken half a glass of wine.
Here absorption must have taken place, either by the skin or
lungs, or both. The difficulties in either case are the same ;
and whatever renders absorption by one probable, will equally
strengthen the probability that absorption takes place by the
other.f
* Phil. Mag. vi. 95.
•J- Watson's Chemical Essays, iii. 101. The Abbe Fontana also found that,
after walking in moist air for an hour or two, he returned home some ounces
heavier than when he went out, notwithstanding he had suffered considerable
evacuation from a brisk purge purposely taken for the experiment. This in-
crease, indeed, might be partly accounted for by the absorption of moisture by
his clothes.
ASSIMILATION. 651
MM. Becquerel and Breschet have found that when a dog or
rabbit is deprived of its hair, and the whole body covered with a
varnish to prevent perspiration, the animal always died in a few
hours, while the temperature of the surface rapidly sank. In a
rabbit from 101° to 76° in an hour. . In another the temperature
of the muscles of the thigh in an hour and a-half was only 5^°
above that of the atmosphere.*
CHAPTER V.
OF ASSIMILATION.
WE have now seen the progress of digestion, and the forma-
tion of blood, as far at least as we are acquainted with it. But
to what purposes is this blood employed, which is formed with so
much care, and for the formation of which so great an appara-
tus has been provided ? It answers two purposes. The parts of
which the body is composed, bones, muscles, ligaments, mem-
branes, &c. are continually changing. Jn youth they are increas-
ing in size and strength, and in mature age they are continually
acting, and consequently continually liable to waste and decay.
They are often exposed to accidents, which render them unfit for
performing their various functions ; and even when no such acci-
dent happens, it seems necessary for the health of the system that
they should be now and then renewed. Materials, therefore, must
be provided for repairing, increasing, or renewing all the various
organs of the body ; phosphate of lime and gelatin for the bones,
fibrin for the muscles, albumen for the cartilages and membranes,
&c. Accordingly, all these substances are laid up in the blood ;
and they are drawn from that fluid, as from a storehouse, when-
ever they are required. The process by which the different in-
gredients of the blood are made part of the various organs of the
body 'is called ASSIMILATION.
Over the nature of assimilation the thickest darkness still
hangs : there is no key to explain it, nothing to lead us to the
knowledge of the instruments employed. Facts, however, have
been accumulated in sufficient numbers to put the existence of
the process beyond the reach of doubt. The healing, indeed, of
* Comptes Rend us, xiii. 791.
FUNCTIONS OF ANIMALS.
every fractured bone, and every wound of the body, is a proof of
its existence, and an instance of its action.
Every organ employed in assimilation has a peculiar office ;
and it always performs this office whenever it has materials to
act upon, even when the performance of it is contrary to the in-
terest of the animal. Thus the stomach always converts food in-
to chyme, even when the food is of such a nature that the pro-
cess of digestion will be retarded rather than promoted by the
change. If warm milk, for instance, or warm blood, be thrown
into the stomach, they are always decomposed by that organ, and
converted into chyme ; yet these substances are much more near-
ly assimilated to the animal before the action of the stomach than
after it. The same thing happens when we eat animal food.
On the other hand, a substance introduced into an organ em-
ployed in assimilation, if it has undergone precisely the change
which that organ is fitted to produce, is not acted upon by that
organ, but passed on unaltered to the next assimilating organ.
Thus it is the office of the intestines to convert chyme into chyle.
Accordingly, whenever chyme is introduced into the intestines,
they perform their office, and produce the usual change ; but if
chyle itself be introduced into the intestines, it is absorbed by
the lacteals without alteration. The experiment, indeed, has not
been tried with true chyle, because it is scarcely possible to pro-
cure it in sufficient quantity ; but when milk, which resembles
chyle pretty accurately, is thrown into the jejunum, it is absorb-
ed unchanged by the lacteals.*
Again, the office of the blood-vessels, as assimilating organs,
is to convert chyle into blood. Chyle, accordingly, cannot be
introduced into the arteries without undergoing that change ;
but blood may be introduced from another animal without any in-
jury, and consequently without undergoing any change. This
experiment was first made by Lower, and it has since been very
often repeated.
Also, if a piece of fresh muscular flesh be applied to the mus-
cle of an animal, they adhere and incorporate without any change,
as has been sufficiently established by the experiments of Mr J.
Hunter; and Buniva has ascertained, that fresh bone may, in
the same manner, be engrafted on the bones of animals of the
same or of different species, f
* Fordyce on Digestion, p. 189. f Phil. Mag. vi. 308.
ASSIMILATION. 653
In short, it seems to hold, at least as far as experiments have
hitherto been made, that foreign substances may be incorporated
with those of the body, provided they be precisely of the same
kind with those to which they are added, whether fluid or solid.
Thus chyle may be mixed with chyle, blood with blood, muscle
with muscle, and bone with bone. The experiment has not been
extended to the other animal substances, the nerves, for instance ;
but it is extremely probable that it would hold with respect to
them also.
On the other hand, when substances are introduced into any
part of the body which are not the same with that part, nor the
same with the substance upon which that part acts, provided they
cannot be thrown out readily, they destroy the part, and per-
haps even the animal. Thus foreign substances introduced into
the blood very soon prove fatal ; and introduced into wounds of
the flesh or bones, they prevent these parts from healing.
Although the different assimilating organs have the power of
changing certain substances into others, and of throwing out the
useless ingredients, yet this power is not absolute, even when the
substances on which they act are proper for undergoing the
change which the organs produce. Thus the stomach converts
food into chyme, the intestines chyme into chyle, and the sub-
stances which have not been converted into chyle are thrown out
of the body. If there happen to be present in the stomach and
intestines any substance which, though incapable of undergoing
these changes, at least by the action of the stomach and intes-
tines, yet has a strong affinity, either for the whole chyme and
chyle, or for some particular part of it, and no affinity for the
substances which are thrown out, that substance passes along
with the chyle, and in many cases continues to remain chemically
combined with the substance to which it is united in the stomach,
even after that substance has been completely assimilated, and
made a part of the body of the animal. Thus there is a strong
affinity between the colouring matter of madder and phosphate
of lime. . Accordingly, when madder is taken into the stomach,
it combines with the phosphate of lime of the food, passes with it
through the lacteals and blood-vessels, and is deposited with it
in the bones, as was proved by the experiments of Bechier* and
» Phil. Trans. 1736, p. 287.
654 FUNCTIONS OF ANIMALS.
Duhamel.* In the same manner, musk, indigo, &c. when taken
into the stomach, make their way into many of the secretions.
These facts show us that assimilation is a chemical process
from beginning to end ; that all the changes are produced ac-
cording to the laws of chemistry ; and that we can even derange
the regularity of the process by introducing substances whose
mutual affinities are too strong for the organs to overcome.
It cannot be denied, then, that the assimilation of food con-
sists merely in a certain number of chemical decompositions
which that food undergoes, and the consequent formation of
certain new compounds. But are the agents employed in assi-
milation merely chemical agents? We cannot produce any
thing like these changes on the food out of the body, and there-
fore we must allow that they are the consequence of the action
of the animal organs. But this action, it may be said, is merely
the secretion of particular juices, which have the property of in-
ducing the wished-for change upon the food; and this very
change would be produced out of the body, provided we could
procure these substances, and apply them in proper quantity to
the food. If this supposition be true, the specific action of the
vessels consists in the secretion of certain substances ; conse-
quently the cause of this secretion is the real agent in assimila-
tion. Now, can the cause of this secretion be shown to be merely
a chemical agent ? * Certainly not. For in the stomach, where
only this secretion can be shown to exist, it is not always the
same, but varies according to circumstances. Thus eagles at
first cannot digest grain, but they may be brought to do it by
persisting in making them use it as food. On the contrary, a
lamb cannot at first digest animal food, but habit will also give
it this power. In this case, it is evident that the gastric juice
changes according to circumstances.
The presence of some agent, different from a mere chemical
power, will be still more evident, if we consider the immunity of
the stomach of the living animal during the process of digestion.
The stomach of animals is as fit for food as any other substance.
The gastric juice, therefore, must have the same power of acting
on it, and of decomposing it, that it has of acting on other sub-
* Phil. Trans. 1740,'p. 390. The fact'was mentioned by Mizaldus in a book
published in 1566, entitled, Memoiabilium, utilium ac jucundorum Centuries
novem.
ASSIMILATION. 655
stances ; yet it is well known that the stomach is not affected by
digestion while the animal retains life ; though, as Mr Hunter
ascertained, the very gastric juice which the living stomach se-
cretes, often dissolves the stomach itself after death. * Now what
is the power which prevents the gastric juice from acting on the
stomach during life ? Certainly neither a chemical nor mecha-
nical agent, for these agents must still retain the same power af-
ter death. We must, then, of necessity conclude, that there ex-
ists in the animal an agent very different from chemical and me-
chanical powers, since it controls these powers according to its
pleasure. These powers, therefore, in the living body, are merely
the servants of this superior agent, which directs them so as to
accomplish always one particular end. This agent seems to re-
gulate the chemical powers, chiefly by bringing only certain sub-
stances together which are to be decomposed, and by keeping at
a distance those substances which would interfere with, or dimi-
nish, or spoil the product, or injure the organ ; and we see that
this separation is always attended to even when the substances
are apparently mixed together ; for the very same products are
not obtained, which would be obtained by mixing the same sub-
stances together out of the body, that are produced by mixing
them in the body ; consequently all the substances are not left
at full liberty to obey the laws of their mutual affinities. The
superior agent, howrever, is not able to exercise an unlimited
authority over the chemical powers ; sometimes they are too strong
for it : some substances, accordingly, as madder, make their way
into the system ; while others, as arsenic, decompose and destroy
the organs of the body themselves,
But it is not in digestion alone that this superior agent makes
the most wonderful display of its power ; it is in the last part of
assimilation that our admiration is most powerfully excited. How
comes it that the precise substances wanted are always carried to
every organ of the body ? How comes it that fibrin is always
regularly deposited in the muscles, and phosphate of lime in the
bones ? And, what is still more unaccountable, how comes it that
prodigious quantities of some one particular substance are formed
and carried to a particular place,in order to supply new wants which
did not before exist ? A bone, for example, becomes diseased
• Phil. Trans. 1 772, p. 447.
656 FUNCTIONS OF ANIMALS.
and unfit for the use of the animal ; a new bone, therefore, is
formed in its place, and the old one is carried off by the absor-
bents. In order to form this new bone, large quantities of phos-
phate of lime are deposited in a place where the same quantity
was not before necessary. Now, who informs this agent that an
unusual quantity of phosphate of lime is necessary, and that it
must be carried to that particular place ? Or, granting, as is
most probable, that the phosphate of lime of the old bone is
partly employed for this purpose, who taught this agent that the
old bone must be carried off, new-modelled, and deposited and
assimilated anew ? The same wonders take place during the heal-
ing of every wound, and the renewing of every diseased part.
But neither in this case is the power of this agent over the
chemical agents which are employed absolute. We may prevent
a fractured bone from healing, by giving the patient large quan-
tities of acids. And unless the materials for new- wan ted sub-
stances be supplied by the food, they cannot in many cases be
formed at all. Thus the canary bird cannot complete her eggs
unless she be furnished with lime.
As this agent which characterizes living bodies does not ap-
pear to act according to the principles of chemistry, any inquiry
into its nature would be foreign to the subject of this work.
Physiologists have given it the name of the living or animal
principle ; and to them I beg leave to refer the reader.
Besides the different organs of the body, the blood is also em-
ployed in forming all the different secretions which are necessary
for the purposes of the animal economy. These have been enu-
merated in a former part of this work. The process is similar to
that of assimilation, and undoubtedly the agents in both cases
are the same ; but we are equally ignorant of the precise man-
ner in which secretion is performed as we are of assimilation.
After these functions have gone on for a certain time, which
is longer or shorter according to the nature of the animal, the
body gradually decays, at last all its functions cease completely,
and the animal dies. The cause of this must appear very extra-
ordinary, when we consider the power which the animal has of
renewing decayed parts ; for it cannot be doubted that death pro-
ceeds, in most cases at least, from the body becoming incapable
of performing its functions. But if we consider that this power
is limited, and that it must cease altogether when those parts of
ASSIMILATION. 6,57
the system begin to decay which are employed in preparing ma-
terials for future assimilation, our surprise will, in some mea-
sure, cease. It is in these parts, in the organs of digestion and
assimilation, accordingly, that this decay usually proves fatal.
The decay in other parts destroys life only when the waste is so
rapid that it does not admit of repair.
What the reason is that the decay of the organs causes death,
or, which is the same thing, causes the living principle either to
cease to act, or to leave the body altogether, it is perfectly im-
possible to say, because we know too little of the nature of the
living principle, and of the manner in which it is connected with
the body. The last is evidently above the human understanding ;
but many of the properties of the living principle have been dis-
covered : and were the facts already known properly arranged,
and such general conclusions drawn from them as their connec-
tion with each other fully warrant, a degree of light would be
thrown upon the animal economy, which those who have not at-
tended to the subject are not aware of.
No sooner is the animal dead, than the chemical and mecha-
nical agents, which were formerly servants, usurp the supreme
power, and soon decompose and destroy that very body which had
been in a great measure reared by their means.
T t
APPENDIX.
No. I.
OF THE MODE OF ANALYZING ORGANIC BODIES.
THE constituents of the greater number of organic bodies are
carbon, hydrogen, azote, and oxygen. In animal bodies usually
all the four exist together ; but in many vegetable bodies, as
acids, alcohols, sugars, starch, and gum, only hydrogen, carbon,
and oxygen are to be found. Now to analyze an organic body
is to determine with accuracy the weight of the carbon, hydro-
gen, azote, and oxygen, respectively, of which it is composed.
The method of performing this analysis was first contrived by
Gay-Lussac, and Thenard, in the year 181 1.* They first inti-
mately mixed the substance to be analyzed with about twice as
much dry and fused chlorate of potash as was necessary to burn
it completely. This mixture was made up into small round balls
about half the size of a pea. They were dried at the tempera-
ture of 212°, and the exact quantity of chlorate of potash and of
the substance to be analyzed, contained in them was accurately
determined. These balls were dropped one after another into a
stout glass tube shut at its lower extremity, and having a stop-
cock cemented into its upper extremity. This stop-cock had no
hole, so that it might be turned quite round without opening any
communication between the external air and the inside of
the tube ; but there was a cavity in it into which the balls
could be put, and when the cock was turned round each ball
dropped in succession to the bottom of the stout tube. From
this perpendicular tube a small horizontal tube, soldered by the
blowpipe, proceeded, dipped into a mercurial trough, to convey
the gas evolved during the combustion into graduated flasks
filled with mercury, and ready to receive it. The bottom of the
tube being heated to a dull red heat, balls were dropped in suc-
* Recherches Physico-Chimiques, ii. 265.
660 APPENDIX.
cessively. Each burnt brilliantly, and a good deal of gas was
evolved which passed into the mercurial trough. This process
was continued till all the common air was driven out of the tube*
and it was filled with nothing but the gas extricated by the com-
bustion of the balls. A number of the balls (first accurately
weighed) were then dropped into the tube and deflagrated, and
the gas evolved collected in a graduated jar. Then another and
another jar was filled in exactly the same manner, each contain-
ing the gas evolved by the combustion of nine or ten grains of
the substance to be analyzed. The bulk of the gas in the first
jar being measured it was subjected to analysis, and consisted of
a mixture of oxygen, carbonic acid, and azotic gas, (if the sub-
stance under examination contained that principle.) The bulk
of the carbonic acid was determined by absorbing it by means of
caustic potash, and that of the oxygen by mixing 100 volumes of
it with 40 of hydrogen, and passing an electric spark through it.
The diminution of volume determined the purity of the oxygen
and the presence or absence of azotic gas, carbonic oxide, &c.
The quantity of oxygen gas evolved from the weight of chlorate
of potash used being known, and the quantity collected and in
the state of carbonic acid gas being subtracted from it, the re-
mainder indicated the volume of oxygen gas which went to the
formation of water. The carbonic acid, hydrogen, and azote
thus evolved by the combustion of the substance under analysis
being known, and the amount of these being added and subtract-
ed from the weight of the substance subjected to analysis, the re-
mainder gave the quantity of oxygen which the substance under
analysis contained.
In this way they analyzed fifteen vegetable substances, none of
which contained azote, and four animal substances, each contain-
ing azote as a constituent
The process of Gay-Lussac and Thenard was considerably
improved by Berzelius in 1814.* He adopted the chlorate of
potash, which he mixed with the substance to be analyzed. The
mixture he put into a stout glass tube, shut at one end. The
open end was luted to a small receiver, which terminated in a
long glass tube filled with dry chloride of calcium. To the end
of this tube was luted a bent tube, plunging into a mercurial
trough with a glass jar filled with mercury to receive the gas
evolved. After the process was over the receiver and chloride
* Annals of Philosophy, 401.
APPENDIX. 661
of calcium tube being weighed gave the quantity of water evolv-
ed. The carbonic acid in the jar, over mercury, was absorbed
by a small glass of potash exactly weighed. The increase of
weight gave the quantity of carbonic acid evolved. The glass
tube containing the matter to be analyzed was strengthened by
a ribbon of tin plate wrapped round it, and it was heated to red-
ness, beginning at the end next the receiver, and passing back-
wards to the lower extremities.
The determining of the water and carbonic acid by weighing
was a considerable improvement upon the process of Gay-Lussac
and Thenard, But the apparatus was rather too complex, and
the number of joinings too many. It would be difficult in this
country, where our corks are bad, to make it always air-tight.
Berzelius subjected from nine to ten grains of the substance un-
der experiment to analysis. He analyzed thirteen vegetable
substances, and as usual his results approached pretty near the
truth.
About the year 1813, Gay-Lussac suggested to" M. Chevreul
the substitution of black oxide of copper for chlorate of potash
in the analysis of vegetable and animal substances. * M. Gay-
Lussac had employed this substitute in his analysis of the com-
pounds of cyanogen, f In 1816, the use of it was highly com-
mended by Dobereiner,J who does not seem to have been aware
of its previous employment in organic analyses in France ; at
least he takes no notice of it.
In 1827, Dr Prout published in the Philosophical Transactions
a memoir entitled On the Ultimate Composition of Simple Alimen-
tary Substances.^ He had been occupied with these analyses for
many years, had tried all the different methods of analysis re-
commended by preceding experimenters, and had found them all
attended with difficulties that prevented him from attaining the
requisite degree of accuracy. This induced him to have recourse
to the combustion of the substances to be analyzed in a tube filled
with oxygen gas. The matter to be analyzed was mixed with the
requisite quantity of oxide of copper. It was then introduced into
the tube. The apparatus was filled with the requisite volume of
oxygen gas, the heat of a lamp was applied to the tube contain -
* Ann. de Chim. xcvi. 53. f Ibid. xcv. 154, 184, 187.
| Schweigger's Jour. xvii. 369. § Phil. Trans. 1827, p. 385.
662 APPENDIX.
ing the mixture of oxide of copper and the body to be analyzed,
and the oxygen gas was driven backwards and forwards through
it, till the combustion was at an end, and till the oxide of cop-
per, partially reduced, had recovered its original quantity of oxy-
gen. The apparatus was then allowed to cool. The oxide of
copper will imbibe all the moisture and air which it contained
before the experiment began. The volume of gas in the tube is
now measured with accuracy. If it is unaltered it follows that
the oxygen and hydrogen in the body analyzed are in the pro-
portion to form water. The volume of carbonic acid gas is then
ascertained from which the weight of carbon is easily deduced.
Subtracting this from the original weight of the substance under
analysis, the remainder is the hydrogen and oxygen in the pro-
portion which constitutes water.
If the volume of gas be increased it is a proof that the oxygen
in the substance analyzed is more than what is necessary to con-
vert the hydrogen into water ; and the increase of volume gives
the additional quantity of oxygen present.
If the volume be diminished it indicates that the hydrogen in
the substance under analysis is more than v/hcit is. requisite to
convert the oxygen into water. And twice the volume of di-
minution gives the volume of hydrogen thus in excess.
This method is susceptible of great accuracy. But it requires
much accuracy in measuring the vc!i:mes of oxygen gas and
carbonic acid gas evolved. And as tha v/jiglit cf the carbon,
and even of the hydrogen, is deduced from the volume, it is ne-
cessary for accuracy that the specific gravity of these gases should
be correctly known.
By this process Dr Prout analyzed twenty-one vegetable sub-
stances (all without azote), and the result in his hands was ex-
ceedingly near the truth. But the complexity of his apparatus,
and the jdifficulties attending minute measurement cf the vo-
lumes of the gases employed or formed, have prevented other che-
mists from following his method. We do not know, therefore,
how it would succeed in the hands of chemists less cautious and
scrupulously accurate than Dr Prout.
The attention of Professor Liebig to the analysis of organic
substances seems to have been drawn by this memoir of Dr Prout.
In 1830, he published a critical examination of Dr Prout's ap-
paratus, pointed out its inapplicability to the analysis of substances
APPENDIX. 663
containing azote, and states several other objections to which it
is unnecessary to refer. *
In 1831, Liebigf made known an apparatus which he had con-
trived, and which greatly facilitated the determination of the
weight of carbonic acid gas formed during the analysis of orga-
nic bodies. The water formed was determined, as Berzelius had
done, by causing the products of the combustion to pass through
a tube filled with fragments of chloride of calcium. The increase
of weight gave the water evolved. The contrivance for collect-
ing the carbonic acid was a glass tube upon which were blown
the two large bulbs «, a, and the three small intermediate bulbs
bf b9 b9 the capacity of all the three being only equal to^that of
one bulb a. The bulbs bt b, b, are filled to the line c, with a
saturated solution of caustic potash, and the whole tube with its
contents, after being accurately weighed, is luted by the extremity
d to the tube containing the chloride of calcium. The glass
tube containing the mixture of oxide of copper and the substance
to be analyzed, after being repeatedly exhausted by means of a
syringe attached to it, passing through a tube filled with chlo-
ride of, calcium to get rid of moisture, is luted to the other ex-
tremity of the tube containing the chloride of calcium, and placed
horizontally on a small iron grate, and heated gradually and
slowly by means of ignited charcoal, and this is continued till
the process is finished, which, if properly conducted, will occupy
about two hours. The increase of weight in the chloride of cal-
* Poggendorf's Annalen, xviii. p. 357. f Ibid. xxi. 1.
664 APPENDIX.
cium gives the quantity of water formed, and the increase of
weight in the potash tube gives the quantity of carbonic acid
formed. From these two it is easy to calculate the weight of
hydrogen and carbon in the substances under analysis. For the
hydrogen is one-ninth of the weight of the water, and the carbon
three-elevenths of that of the carbonic acid.
Professor Liebig in the same paper showed how an estimate
might be formed of the quantity of azote contained in the sub-
stance to be analyzed by subjecting it to a second analysis, in
which the tube with the potash was left out, and the mixture of
azotic and carbonic acid formed received in a set of ten or twelve
graduated tubes filled with mercury, and standing on the mer-
curial trough. The ratio of the carbonic acid and azotic gas in
each is determined by absorbing the carbonic acid gas ; and that
ratio gives the ratio of the atoms of azote and carbon. Suppose
one volume azote and four volumes carbon, then for every atom
of azote there are four atoms carbon. From these data, know-
ing the specific gravities of azotic and carbonic acid gases, it is
easy to deduce the weight of azote in the substance under ana-
lysis.
It was this apparatus of Liebig which gave popularity to orga-
nic chemistry. The mode of analysis appeared easy and simple.
Liebig devoted his laboratory to organic investigations. His
pupils increased in number, and he started a periodical work en-
titled Annalen der Pharmacie, in which the labours of his nume-
rous pupils were consigned. Organic analyses increased in num-
ber, and almost every animal and vegetable principle was subjected
to this important scrutiny. Facts were increased prodigiously, as will
be evident to the most careless observer, if the contents of the two
volumes regarding animal and vegetable substances be inspected.
But the defects of oxide of copper as a means of analysis,
pointed out by Prout, especially its property of absorbing mois-
ture and air with avidity, rendered it desirable that some substi-
tute free from these defects should be discovered. Liebig point-
ed out a substitute in 1837 in chr ornate of lead, the employment
of which was first tried by Mr Richardson.* It is prepared by
precipitating a salt of lead by bichromate of potash. The preci-
pitate is well-washed, dried, and melted in a Hessian crucible. It
is then pulverized, and, being put into a stoppered bottle, is ready
for use. This salt has the important property of neither absorb-
* Annalen der Pharm. xxiii. 58.
APPENDIX. 665
ing moisture nor air. Hence, when it is used, the water formed
during the process may be determined with more accuracy than
with oxide of copper. It gives out more oxygen than oxide of
copper, and therefore admits a greater weight of the substance
under analysis to be employed, which is of great consequence ;
for we cannot expect accurate results unless the quantity ana-
lyzed amount to fifteen or twenty grains."
In the fifth volume of Dumas' Traite de Chimie appliquee aux
Arts, (p. 3), published in 1835, he has given a minute detail of
the methods employed by him to secure accurate results when
organic bodies are analyzed by means of oxide of copper. It will
be worth while to state some of the most important of these me-
thods, or checks, as they may be called.
The oxide of copper should not be prepared by precipitating a
salt of copper by means of an alkali, because it has been ascer-
tained that some of the alkali is apt to adhere to the oxide. We
may obtain pure oxide of copper by heating turnings of that metal
in a muffle till they are thoroughly oxydized, or by exposing ace-
tate of copper to long- continued ignition in an open vessel. But
one of the best sources of oxide of copper is the nitrate ignited
in an open vessel. It gives a light, free, and very good oxide,
but it should be well pounded and calcined a second time, in
order to be sure that all the nitric acid has been driven off.
The glass-tube in which the combustion is made must be of
crown-glass, that it may be heated to redness without melting.
Its internal diameter should be about 0-4 inch, and its length
not less than sixteen inches. One end should be shut and drawn
out by the lamp into a fine point, c. The other end should be
30=
smoothed by a file, to prevent it from injuring the cork to be
fitted to it. The figure here given represents the combustion
tube with the chloride of calcium tube a luted to it. About 1*5
inch at the bottom of the tube should be filled with oxide of cop-
per. Then the mixture of oxide of copper and the substance to
be analyzed occupying the space of several inches. The rest
of the tube should be filled with oxide of copper. If the tube be
quite filled with oxide of copper, the gas evolved by the combus-
tion will force it out of the tube and spoil the analysis. Liebig
gets over this difficulty by tapping the tube after filling it, so as
666 APPENDIX.
to leave a small empty space at the upper part of it through which
the gas may flow without impediment. Dumas mixes the oxide
of copper, and the mixture of oxide of copper, and the body
under analysis, with copper turnings, along which the gas finds
its way. Others insert in the axis of the tube a copper wire,
along which the gas passes. Some one of these precautions seems
necessary, yet they render the complete combustion of the sub-
stance under analysis more difficult. Should any carbonic oxide
or carburetted hydrogen be mixed with the carbonic acid gas, it
may make its way through the apparatus and be lost altogether.
Hence it generally happens that the quantity of carbon obtained
by such analyses is below the truth. In Liebig's laboratory, in-
deed, this error was in some measure compensated by estimating
the atomic weight of carbon almost two per cent, too high. The
true atomic weight of carbon is O75 ; but Liebig adopted Ber-
zelius's number, 0*76435, which exceeds the truth by 1-913 per
cent. The only sure way of burning the substance under ana-
lysis completely is Dr Prout's method of furnishing a supply of
oxygen gas. Probably the mixture of the oxide of copper with
a certain quantity of fused chlorate of potash, would answer the
purpose ; or the length of that part of the tube filled with oxide
of copper or chromate of lead might be considerably increased,
and the whole might be kept at a red heat while the gas was
made to pass very slowly through it To prevent the tube from
losing its shape it should be wrapt round with tinsel or a ribbon
of sheet copper.
Great care is necessary in introducing the substance to be
analyzed into the tube. If it be a solid it should be dried tho-
roughly at 212°, or at a higher temperature, if it will bear it with-
out decomposition. A given weight should then be put into a
dry warm porcelain mortar and triturated with nine or ten times
its weight of oxide of copper or chromate of lead. It is then,
while still warm, to be introduced into the tube. If the sub-
stance to be analyzed be very volatile, as camphor, naphthalin, &c.,
it is needless to triturate it with the oxide of copper. It is only
necessary to introduce fragments of it into the tube alternating
with oxide of copper till the requisite weight has been added, and
then to proceed to analysis in the common way. When the li-
quid is volatile, but not exceedingly so, but boiling between 248°
and 572°, it is to be put into a small tube shut at one end and
open at the other. This tube is introduced into the decomposing
APPENDIX. 067
tube after some oxide of copper, and then the tube is filled with
oxide of copper, and the analysis begun. When the substance
to be analyzed is very volatile, as alcohol, ether, &c., it is intro-
duced into a little glass bead, drawn out into a capillary point
by the lamp. This bead is slipt into the decomposing tube, and
covered in the usual way with oxide of copper, &c., and the ana-
lysis proceeded in.
When the substance to be analyzed contains azote, precau-
tions are necessary to decompose certain compounds of azote
which are apt to be formed. It may make its escape in the state
of ammonia, or protoxide of azote, cr deutoxide of azote. The
ammonia will be decomposed into water and azotic gas in pas-
sing through the O7xide of copper in a state of incandescence.
The other two gases to be decomposed must be passed through
a considerable length of red hot copper turnings. The oxygen
of the gases combines with the copper, and the azote makes its
escape and may be collected over mercury. In such cases the
decomposing tube must be longer than ordinary, and must be di-
vided into four compartments, the first filled with oxide of cop-
per, the second with oxide of copper and the substances to be
analyzed, the third with oxide of copper, and the fourth with cop-
per turnings.
We must begin with heating to redness the extremity of the
tube next the open end, and we must gradually bring the fire
along the tube, and the whole copper turnings and oxide of cop-
per must be red hot before we apply the heat to the mixture of
oxide of copper and the substance to be analyzed. Care must
be taken to keep the open extremity of the tube hot to prevent
any accumulation of vapour there, which would prevent the suc-
cess of the analysis.
We may form an idea of the success of the analysis by the ap-
pearance of the carbonic acid gas as it is condensed in the po-
tash tube. If it comes over regularly and slowly, if it is quite
colourless and without smell, we may conclude that our process
is going on well. If, on the other hand, it be cloudy, coloured,
and, above all, if any oily matter make its appearance in the tubes,
we may conclude that the combustion of the matter under ana-
lysis is incomplete, and that portions of the carbon and hydrogen
are making their escape in the form of oily vapour.
When an analysis is happily conducted the formation of gas
ceases all at once. When carbon has escaped combustion, and
668 APPENDIX.
is mixed with the oxide of copper, the evolution of gas goes on
for a long time. In such cases we should always mistrust the
accuracy of our analysis.
M. Dumas's method of determining the quantity of azote in a
body under analysis is somewhat different from that of Liebig,
and when the combustion is complete (which, however, is diffi-
cult,) seems quite accurate. It will be worth while to state it
here : Into the bottom of the decomposing tube some grammes
of pure dry carbonate of lead are introduced. Above it, b, is
put a mixture of oxide of copper and copper turnings. In c is
1 I
put a mixture of oxide of copper, and the body to be analyzed ;
in e ten or twelve grammes of oxide of copper mixed with some
turnings ; while the outer portion is filled with copper turnings.
The tube is connected with a mercurial trough, exhausted, and
then a portion of the carbonate of lead is heated. The carbonic
acid evolved drives out the common air in the tube, taking its
place, and the process is continued till pure carbonic acid passes
into the mercurial trough, and is totally absorbed by the potash
placed for the purpose. The whole portion e of the tube is then
made red hot, and the portion c being gradually heated the azotic
gas evolved is passed into the gas-holder over mercury. When
it ceases to come over heat is applied to the rest of the carbonate
of lead in «, which carries with' it all the azotic gas remaining in
the tube. The carbonic acid is absorbed by the potash, and no-
thing remains but the azotic gas. Its volume is measured, and
its specific gravity being 0-9722, it is easy to determine its weight.
This method is very good ; but another has been lately contrived
by Drs Will and Varrentrapp, which will be stated below.
The hydrogen is determined by means of dry fused chloride
of calcium, as first proposed by Berzelius. The mixture of oxide
of copper and the substance under analysis is put into the com-
bustion tube. This tube is luted, by means of an excellent cork,
to a long tube filled with fragments of chloride of calcium, and
this long tube is attached to a small air-pump, or rather syringe,
The air is exhausted, and then allowed to flow back through the
APPENDIX. 669
tube filled with chloride of calcium, which renders it very dry.
The exhaustion being repeated in this way fifteen or twenty
times, the moisture which the oxide of copper so readily imbibes
is withdrawn, and the whole made dry. The decomposition is
then begun and completed in the way already explained. The
increase of weight of the chloride of calcium tube gives the quan-
tity of water formed, and the ninth part of the weight of water
is the amount of hydrogen contained in the substance under ana-
lysis. In general, the weight of hydrogen obtained exceeds a
little that of the hydrogen in the substance under analysis. That
is the consequence of the difficulty of depriving the oxide of cop-
per of all moisture. The excess is so much less when chromate
of lead is used: indeed, if the proper precautions be used, the
error in that case may be considered as evanescent. The whole
water is not absorbed by the chloride of calcium, a portion of it
is usually deposited in a liquid state in the small bulb at the end
of the chloride of calcium tube next the decomposing tube.
As common cork imbibes moisture it cannot be used when we
wish to determine the hydrogen with very great accuracy. In
that case, the tubes should be ground into each other so as to be
air-tight.
Liebig's potash tube answers so well for determining the car-
bon by the weight of the carbonic acid evolved, that no addi-
tional observations in that subject seem necessary.
Liebig's method of determining the azote is somewhat differ-
ent from that described above, which is the method of Dumas.
He puts into the bottom of the decomposing tube a quantity of
hydrate of lime ; and after the combustion is at an end, the hy-
drate of lime is heated, and its water converted into steam, which
forces all the gas remaining in the apparatus into the gas tubes
standing over mercury. These are filled in succession, and the
ratio between the volume of carbonic acid and azotic gas being
determined, it is easy to calculate how much azote the substance
under analysis contained.
But it must be acknowledged that both the process of Dumas
and of Liebig leaves considerable uncertainty, and that they af-
ford at best only approximations to the truth. A new method
has been recently proposed by Drs Varrentrapp and Will, which
is both of easier execution, and promises to be susceptible of
greater accuracy than any of the old methods.*
* Ann. der Pharm. xxxix. 257.
670 APPENDIX.
It is founded upon the great affinity which exists between
azote and hydrogen. Whenever any substance containing azote
and hydrogen is heated in contact with potash, lime, barytes, &c.
it always gives out ammonia. Now ammonia is a compound of
Az H3. Almost every organic body containing azote contains
also hydrogen ; and the quantity of hydrogen is always sufficient
for converting the azote into ammonia. This conversion al-
ways takes place. Hence we may determine the quantity of
azote in any substance, by ascertaining the weight of ammonia,
which it gives out when decomposed. Such is the basis of the
method of Varrentrapp and Will.
Guy-Lussac has shown, that, if hydrate of potash be mixed
with an organic body destitute of azote, the water of the hydrate
is decomposed ; its oxygen uniting with the carbon and hydro-
gen of the organic body, while its hydrogen is disengaged in the
state of gas. The products formed by this energetic process of
oxydizement vary according to the temperature to v/hich the mix-
ture is exposed, and according to the constitution of the organic
body. It is enough to state here, that when the organic body is
destitute of azote, hydrogen gas is disengaged. When the or-
ganic body contains azote, this free hydrogen unites with the
whole of that azote, and is converted into ammonia. This pro-
cess has been long in use to ascertain whether an organic body
contains azote or not
When a substance contains a great deal of azote, as uric acid,
melamin, mellon, &c., it is natural to suppose that the whole
azote may not be converted into ammonia, A portion of it may
unite with part of the carbon of the substance, and form cyano-
gen, and this cyanogen (as also cyanic acid) may unite with the
alkali or its bases. And as such a combination may resist de-
composition at a high temperature, we may conjecture that a por-
tion of the azote may be retained, and not make its appearance
in the state of ammonia.
But Drs Varentrapp and Will have ascertained by direct ex-
periment that when a sufficient quantity of hydrate of potash is
employed, and when the heat is not too low, the whole azote, even
in the compounds just mentioned, is converted into ammonia.
When cyanodide of potassium, cyanate of potash, or paracyanic
acid is heated to redness with an excess of hydrate of potash, or
with a mixture of hydrate of potash or soda, with caustic lime, an
abundant evolution of ammonia takes place, and in the residue,
APPENDIX.
671
no trace of cyanogen or of any of its compounds can be discover-
ed. In such experiments it is necessary to employ so much al-
kaline hydrate, that the whole carbon of the matter be oxydizefl
by the oxygen of the water of the hydrate. The mixture in the
decomposing tube, after the process is finished, must be quite
white. In proportion to the richness of the organic body in car-
bon, and according to the temperature, there are given out along
with the ammoniacal gas other permanent gases, as the gas of
marshes, hydrogen gas, olefiant gas, or a mixture of these, and
in many cases liquid compounds of carbon and hydrogen, or at
least drops of oily matter.
To the bodies richest in azote belong melamin, mellon, cyano-
gen, and its compounds. But they all contain as much of (or
more) carbon in proportion to their azote, as is sufficient by its
oxydizement to set free a sufficient quantity of hydrogen to con-
vert the whole azote into ammonia. In some of these compounds,
as mellon, whose formula is C6 Az4, and melamin, which is C6
H6 Az6, the decomposition, when a sufficient quantity of alka-
line hydrate is employed, goes on and is completed without the
evolution of any permanent gas. All the carbon is converted
into carbonic acid, which remains combined with the alkali, while
all the azote is converted into ammonia, which flies off in the
state of gas, but is absorbed by the muriatic acid placed in the
tube to collect it
The process employed by Varrentrapp and Will for collecting
the ammonia from the decomposition of bodies containing azote
is founded upon the facts that have been just stated. The orga-
nic body is mixed with a sufficient quantity of hydrate of potash
or hydrate of soda, previously mixed with caustic lime. It is put
into a crown glass tube from 16 to 18 inches long, and about 3
672 APPENDIX*
lines wide. The shut end is to be drawn out into a long point,
which is hermetically sealed. To the open end of this tube is
fixed, by means of a good cork, so as to be air-tight, the bent
tube, a, b, c, somewhat resembling Liebig's potash tube ; but
having only the three bulbs, a, b, c. The central bulb, b, is fil-
led with a quantity of muriatic acid of commerce to absorb the
ammonia. The avidity of muriatic acid for ammonia is so great
that there is no risk of any loss.
The hydrate of potash or soda is to be mixed with so much
quicklime, that the whole can be easily reduced to powder, and
that it should not melt, but only soften a little in the decompos-
ing tube. As hydrate of soda has a smaller atomic weight than
hydrate of potash, it is to be preferred. One part of hydrate of
soda mixed with two parts of anhydrous lime will answer. When
hydrate of potash is used, it should be mixed with thrice its weight
of quicklime. The best way is to heat the hydrate of alkali to
redness, so as to bring it into a state of fusion. It ought, then,
to be rapidly pounded in a warm mortar, and intimately mixed
with the lime. And while still dry, it must be put into a well-
stoppered phial and kept for use.
The decomposing tube is now about half-filled with this mix-
ture. The quantity of the organic body containing azote requi-
site varies with the quantity of azote which it contains. Ac-
cording to Varrentrapp and Will, it is not necessary to use more
than six or less than three grains. It is to be mixed with the
hydrate of soda and lime in a warm and dry mortar, and consi-
derable precautions are necessary to prevent any loss.
The muriatic acid tube is attached to the decomposing tube by
a good cork ; and care must be taken to ascertain that the ap-
paratus is air-tight. The open end of the tube, which contains
no organic matter, is first to be heated to redness, in order to pre-
vent any of the organic matter from passing without being de-
composed completely. The cork must be kept as warm as pos-
sible, that no moisture may lodge about it ; because such a de-
position would cause a loss of azote by absorbing some ammo-
nia.
As soon as the open end is red hot, the fire is removed farther
back. The oxygen of the alkaline hydrate forms carbonic acid
with the whole or with a portion of the carbon in the organic
body, while the hydrogen combines with the azote and forms am-
APPENDIX. 673
monia, which escapes in the gaseous form. At the same time
there escapes, (according to the nature of the organic substance,)
either pure hydrogen gas, or carburetted hydrogen, which are
not absorbed by the acid, and which are easily recognized by
burning them with oxygen gas.
The combustion goes on so rapidly, that a constant current of
gas passes off. But there is no risk of any of the ammonia es-
caping ; it is absorbed so rapidly and so completely by the mu-
riatic acid. When the action of the fire is suddenly stopped, the
whole acid liquor gets into the ball a, and it may even (unless
care be taken) make its way into the decomposing tube, and de-
stroy the analysis.
But few substances contain so much azote, that, in order to
convert the carbon into carbonic acid, the whole hydrogen set
free combines with the azote into ammonia.
To prevent the too rapid absorption of the ammonia, Varren-
trapp and Will recommended mixing those substances which con-
tain a great deal of azote, with sugar or some organic body des-
titute of azote. This last substance, by its decomposition by
means of the alkaline hydrate, gives out a permanent gas, which
dilutes the ammoniacal gas, and prevents its too rapid absorption.
When the process is at an end, and this is known by the ceas-
ing of the evolution of all gas, and by the substance in the de-
composing tube being quite white, the point a of the decompos-
ing tube is to be broken off, and air slowly sucked through the
apparatus by applying the mouth to the extremity^. The ob-
ject of this is to extract any ammonia that may remain and cause
it to be absorbed by the muriatic acid.
The ammonia, while in contact with alcohol and charcoal in
the decomposing tube, might form cyanogen or cyanodide of po-
tassium. The white appearance of the residue in the decompos-
ing tube is a proof that the heat has been sufficient to burn all the
carbon, and that the formation of cyanogen is not to be dreaded.
Such- is the mode of analysis of solid bodies containing azote.
The number of organic liquids containing azote is small. The
process for analyzing them is quite similar. A portion of the
decomposing tube is filled with the mixture of alkaline hydrate
and lime, then the glass globule containing the liquid to be ana-
lyzed is dropt in, and the tube is filled with mixture of alkaline
hydrate and lime. The process of decomposition is the same as
before.
uu
674 APPENDIX.
After the process is completed, the liquid in the muriatic acid
tube is emptied into a porcelain basin, and the tube is to be washed
quite clean with a mixture of alcohol and ether. About an
ounce or an ounce and a half is sufficient to wash out all the sal-
ammoniac which is left in it. An excess of chloride of platinum
is now added to it, and the whole is evaporated to dryness over the
water-bath. If the process has been rightly conducted, the am-
monia-chloride obtained has a fine yellow colour. When the
organic body decomposed contained much carbon, and was diffi-
cult to burn, the platinum precipitate has a darker colour, be-
cause the muriatic acid being evaporated in contact with car-
buretted hydrogen blackens. But this has no influence on the
result, provided the chloride be carefully washed.
The dry residue in the porcelain dish when cold is to be
treated with a mixture of two volumes of strong alcohol and one
volume of ether, in which the platinum sal-ammoniac is quite in-
soluble, though the chloride of platinum dissolves in it readily.
We easily know by the yellow colour of the solution if an excess
of chloride of platinum has been employed. If the solution be
colourless, it follows that too little of that chloride has been em-
ployed.
The platinum sal-ammoniac must be collected on a filter,
dried, and washed with alcohol and ether till these liquids
pass through colourless. It is then to be dried at 212°, and
weighed. It is a compound of one atom of bichloride of pla-
tinum and one atom of chloride of ammonium. Bichloride of
platinum is PI Chi2 = 21, and chloride of ammonium is Az
H4 -f Chi = 6-75, so that 27*75 grains of it contain 1-75 of
azote. Hence, if we multiply the ammonia-bichloride of plati-
num obtained by 14, and divide the product by 222, the quo-
tient will give the weight of azote which it contains. If we ex-
pose this yellow powder to a good red heat, everything will be
driven off except the platinum. Now, 27*75 of the salt leave
12 of platinum. Hence, if we heat to redness, and weigh the
residue, every 12 grains is equivalent to 175 grains of azote.
If, therefore, we multiply the weight of platinum powder ob-
tained by 1*75, and divide the product by 12, the quotient will
give the weight of azote in the quantity of organic matter sub-
jected to analysis.
From the experiments of Varrentrapp and Will, it appears that
APPENDIX. 675
this process does not answer when the body analyzed contains
azote in the form of nitric acid, not even when mixed with six
times its weight of sugar. Indeed, the late experiments of M.
Reiset have shown that the process of Varrentrapp and Will is
not susceptible of absolute accuracy. When bodies destitute of
azote, as sugar and stearin, are heated in a combustion tube
with a mixture of lime and hydrate of soda, a certain portion of
ammonia always makes its appearance, derived from the azote of
the common air contained in the tube. This azote first unites
with carbon, and forms cyanogen, and the cyanogen is ultimately
converted into ammonia. Sugar treated in this way gave 1'03 per
cent, and stearin 0'92 per cent of ammonia. The error from this
source in the eighteen analyses made by Varrentrapp and Will,
namely, of urea, uric acid, taurin, oxamide, caffein, asparagin,
melamin, hippuric acid, amygdalin, narcotin, piperin, brucin,
harmalin, fibrin, albumen, and casein, protein and oil of mustard
was exceedingly small. But if Manzini's analysis of cinchovina
be correct, that it contains 7 '18 per cent, of azote, the error,
when the azote is determined by mixing it with sugar, and col-
lecting the ammonia formed, is so great that the azote is increas-
ed from 7-18 to 11*95, or 4-77 per cent.*
Such are the methods of determining the carbon, hydrogen,
and azote contained in organic bodies. These being added to-
gether, and the sum subtracted from the weight of the organic
body subjected to analysis, the remainder must represent the
weight of oxygen which the body contains ; but which, from the
way in which the carbon and hydrogen are obtained, united to
oxygen, cannot be evolved in a separate state.
Having obtained the weight of each constituent in 100 parts -
of the organic body subjected to analysis, the next step is to de-
termine the number of atoms of each ingredient contained in an
integrant particle of the organic body. To determine this we
must know the atomic weight of the body under examination.
Now this body may be an acid, or a base, or a volatile neutral
body, or a fixed volatile body.
1. To determine the atomic weight of an acid we must, in the
first place, ascertain how much water it contains when in crys-
tals, how much of this water can be driven off by the highest tem-
perature which it can bear without decomposition, and how
* Ann. de Cbim. et de Phys. (3d series), v. 469.
676 APPENDIX.
much more it loses when strongly heated with a given weight of
oxide of lead. Suppose we have 7*875 of oxalic acid crystals. If
we expose these crystals to the highest temperature they can
bear, without decomposition, the loss of weight will be 2*25,
which is equivalent to two atoms water. If we mix the 5*625 of
residue with fourteen yellow oxide of lead, and heat, the loss of
weight will be 1*125, which is equivalent to another atom of
water, and there will remain a neutral compound of fourteen
oxide of lead, and 4*5 oxalic acid. But fourteen is an atom of
oxide of lead, consequently 4*5 is an atom of anhydrous oxalic
acid. Now, as oxalic acid is a compound of,
Carbon, . . 33*33
Oxygen, ;>w . 66*66
It is obvious that it must be composed of,
2 atoms carbon, . . 1*5
3 atoms oxygen, . . 3*
4*5
Because this number of atoms alone gives the ratios and the ato-
mic weight of the acid.
As another example let us take 26*25 of crystals of citric acid,
and heat them sufficiently. The water driven off will weigh
2*25. If we mix the residual 24 with 42, or any greater quan-
tity of oxide of lead, and heat in a crucible, taking care not to
decompose the acid, there will remain 62*625. From this, if we
subtract 42, the weight of the oxide of lead, there will remain
20*625 for the weight of the anhydrous acid. The loss of weight,
consequently, is 3*375, which represents 3 atoms of water. These
three atoms of water have been replaced by 42, or three atoms
of oxide of lead. Hence, citric acid is tribasic, and its atomic
weight in the anhydrous state must be 20*625. It is composed of,
Carbon, fxtf- • . 43-636
Hydrogen, . . 3*030
Oxygen, « #> . 53-334
100
Hence the number of atoms in it must be,
12 carbon, = 9
5 hydrogen, = 0*625
11 oxygen, =11*
20*625
APPENDIX. 677
Because this is the number that gives the atomic weight, and the
ratio of the constituents.
From these examples it will be evident that, in order to have
the atomic weight of an acid, we must be able to get it quite an-
hydrous. But in many cases we cannot drive off the whole of
the water which it contains without substituting some other base.
Now oxide of lead and oxide of silver are the two bases that
answer best for obtaining anhydrous salts. Oxide of lead is
most convenient because it is cheapest. We must determine the
weight of water that escapes and the weight of oxide of lead which
takes its place. These will bear a certain ratio to each other.
If the water be 1-125 and the oxide of lead 14, then the acid is
monobasic, and its atomic weight is obtained by simply analyzing
its salt of lead, reckoning the weight of oxide of lead in it 14,
and calculating the corresponding weight of the acid. If the
water displaced be 2-25, and the oxide of lead substituted in its
place 28, then the acid is bibasic, and so on.
What are called ethers are combinations of an atom of acid
with an atom of C4 H5 O. A good way of determining the atomic
weight of an organic acid is to convert it into ether and to ana-
lyze in the ordinary way the ether obtained. Being composed
of an atom of acid and an atom of C4 H5 O, it is easy from that
analysis to deduce the atomic weight of the acid.
The mode of determining the atomic weight of bases is so
nearly the same with that of acids that but few remarks are ne-
cessary. A given weight of the base dried at 248®, may be dis-
solved in alcohol. The solution may be mixed with water and
the alcohol distilled off. We may then exactly neutralize the
base with sulphuric acid, and, by decomposing afterwards by chlo-
ride of barium, determine the weight of sulphuric acid capable
of saturating a given weight of base. This (if we suppose an
atom of base to saturate an atom of acid) gives us data for cal-
culating the atomic weight of the base.
Liebig employs another method, which often answers very well.
It consists in causing a current of dry muriatic acid gas to pass
through 'a glass tube blown into a ball in which a weighed quan-
tity of the base is placed. The increase of weight gives the
quantity of muriatic acid which has united to the base, and en-
ables us to calculate the atomic weight of that base. The muri-
678 APPENDIX.
atic gas is dried by passing through a tube filled with chloride
of calcium.
When neutral bodies, which do not enter into definite com-
pounds with other substances, are volatile, as the volatile oils, Du-
mas has pointed out a very ingenious method of determining their
atomic weight by the density of their vapour. He puts into a
glass balloon a quantity of the substance, the density of which is
to be determined, and then draws out the mouth of the balloon
to a capillary point that it may be easily hermetically sealed.
The balloon is then heated from 70° to 100° above the boiling
point of the substance, whose specific gravity is to be determined,
arid it is kept at that temperature till all the excess of the sub-
stance is driven out of the balloon. When this has taken place
the capillary end of the mouth is hermetically sealed. The ves-
sel is now filled with vapour at a known temperature, under the
pressure of the atmosphere at the instant that the balloon was
shut. The volume of the balloon and the weight of matter con-
tained in it being known we have all the necessary data for de-
termining the specific gravity of the vapour.
The balloon or globular glass vessel should be of clear glass,
equal and not too thick. Its capacity should not be less than
fifteen nor more than thirty cubic inches. It must be washed
clean in the inside, and dried by passing a current of air through
H while hot. The mouth must then be drawn out into a long
capillary tube. The air which it contains is dried by putting the
balloon under the receiver of an air pump, exhausting the receiv-
er, and causing the air to return into the receiver through a tube
filled with dry chloride of calcium. By repeating the exhaustion
two or three times the air in the balloon will be quite dry. The
balloon is then weighed, marking the height of the thermometer
and barometer at the time.
If the substance, the density of whose vapour is to be taken,
acts on the air of the atmosphere, we must fill the balloon with
hydrogen or carbonic acid gas.
The balloon is now to be gently heated, and the beak of it
plunged into the substance, the specific gravity of whose va-
pour is to be determined, which is supposed to be either liquid or
to be liquefied by a moderate heat. In proportion as the balloon
cools the substance enters into it. We should allow about 80
grains of it to enter.
APPENDIX. 679
When we operate on a substance that boils at 212° or at a
higher temperature, its introduction into the balloon is attended
with no difficulty. But if it be very volatile, as soon as it comes
into the balloon it gives out much vapour, stops the process, or
even drives out again the portion which has entered. To reme-
dy this the balloon is sprinkled with ether, and we blow upon it,
with a bellows to hasten the evaporation. This cools the balloon,
and allows the process to proceed ; on the other hand, when we
operate upon a substance whose melting point is a little elevated,
it becomes solid in the capillary tube and stops the process. To
remedy this we take up the balloon with a pair of pincers, and
hold it over a charcoal fire, so that the temperature of the capil-
lary portion is heated. If we now plunge the capillary point in-
to the substance it passes in without becoming solid.
The balloon being thus charged it is put into the bath in which
the experiment is to be conducted. If the matter boils below
212°, the bath consists of water ; if below 393° we employ a bath
of fixed oil ; if above 400°, the bath must consist of fusible metal.
We might raise an oil bath to 572° or even to 600° ; but we
would run the risk of setting fire to the apartment. The expe-
riment on that account would require to be performed out of
doors. The bath should be such that it can be raised 100°
above the boiling point of the liquid, the density of whose va-
pour we wish to determine. If attention is not paid to this the
specific gravity of the vapour will be too high.
The liquid employed for the bath is put into a cast iron pot.
The balloon is attached to an iron triangle, which is kept plunged
into the liquid by three leaden weights attached to the ends of
the triangle — a thermometer is plunged into the bath to indicate
the temperature. The fire is lighted, and continued till the bath
reaches the boiling point of the liquid in the balloon. Vapour
then issues from the capillary beak, and continues till the whole
is driven off, and nothing remains but vapour, with which the
balloon is filled. We must continue the heat for some time after
the evolution of vapour is at an end. The capillary end of the
balloon is then hermetically sealed. To see whether the sealing
is complete we have only to blow cold air on the beak of the bal-
loon. The vapour condenses in the capillary tube into a liquid,
but this does not happen if the sealing be not complete.
No farther precautions are necessary if the bath be water.
680 APPENDIX.
When an oil bath is used there is more difficulty in obtaining the
same temperature in the vapour and the bath. When the oil
bath is heated to within 20° or 30° of the point at which we wish
to stop we must damp the fire. This causes the temperature to
rise more slowly. When we are within 8° or 10° of the point
the fire must be drawn. This causes the increase of temperature
to be very slow, and enables that of the vapour to become as high
as that of the oil.
The balloon is now removed from the bath, and wiped clean
with the greatest care. When cold and clean it is weighed.
The increase of weight gives the quantity of matter in the balloon
that had been converted into vapour.
The beak is now plunged into mercury and the point broken
off. The mercury enters the balloon and fills it completely, if
the whole air had been expelled. If not, a portion of air remains,
the volume of which must be noted and subtracted from the ca-
pacity of the balloon. When the experiment has been properly
made the residue of air does not exceed Ol or 0-2 cubic inch.
The capacity of the balloon is determined by filling it with
mercury, and measuring the mercury by pouring it into a gra-
duated vessel. By these determinations we know the weight of
the vapour and its bulk, from which we deduce the specific gra-
vity. The excess of the weight of the balloon full of vapour,
minus the weight of the air which the balloon contains, gives us
the weight of the vapour.
Knowing the volume of the balloon and the temperature of
the air when it was weighed, we bring this volume by calculation
to what it would be, supposing the thermometer at 32° and the
barometer at 30 inches, and this corrected volume is converted
into weight, by the known weight of 100 cubic inches of air at
32°, and when the barometer stands at 30 inches; namely,
32-79 grains.
As the balloon was increased in bulk by the high temperature,
we must calculate how much that was, and allow for it. This is
easily done, as we know that the expansion of glass for 1° of Fah-
renheit is Ts JST. All these corrections being made we have the
weight and the bulk of the vapour ; and, dividing the latter by
the former, the quotient gives us the specific gravity of the va-
pour under examination.
Now let us see how this knowledge of the specific gravity of
APPENDIX. 681
a vapour may be applied to the knowledge of its atomic weight,
and consequently of the number of atoms which it contains. Let
us take benzoic acid as an example. It is composed of,
Carbon, . . 74-34
Hydrogen, . .4-42
Oxygen, . . 21-24
100-00
The specific gravity of its vapour, as determined by Dumas and
Mitcherlich, is 4-27. Now the specific gravity of a volume of
carbon vapour and hydrogen gas, and of half a volume of oxy-
gen gas* is as follows :
Carbon, . . 0-4166
Hydrogen, . 0-0694
Oxygen, . . 0-5555
The atomic weight is 14-125. Now it is easy to see that C14 H5
O3 give that atomic weight. To see whether the specific gravity
of the vapour of benzoic acid agrees with this number, we have,
14 volumes carbon weigh 5*8333
5 volumes hydrogen, . 0*3472
1^ volume oxygen, „ . 1-6666
7-8472
If these 22 atoms were condensed into one volume the speci-
fic gravity of the vapour would be 7*8472. But this great con-
densation seldom takes place. In general we must divide by
2, showing that the atoms are condensed into two volumes in
the vapour. Dividing 7-8472 by 2, we have 3-9236, which ap-
proaches pretty nearly to the density of the vapour found by ex-
periment.
Let us take another example in which the atomic weight can-
not be determined directly ; that we may see the use that may
be made of the specific gravity of the vapour. Let the substance
be camphor. It is composed of,
Carbon, . 78-94
Hydrogen, . 10*53
Oxygen, . 10-53
100-00
* The reason of taking a volume of the first two and half-a-volume of oxy-
gen, is, that a volume of carbon and a volume of hydrogen are each reckoned
equivalent to an atom, while a volume of oxygen is equivalent to two atoms.
682 APPENDIX.
The specific gravity of its vapour, as determined by Dumas, is
5-337.
To obtain an idea of the number of atoms which it may con-
tain, let us divide the constituents per cent, by the atomic weight
of each constituent.
Carbon, . 2*| = 105-25
'/O
Hydrogen, v - ^ = 84-24
Oxygen, ^ q !£*? - 10-53
Hence the ratios of the respective atoms are, 105-25, 84-24,
and 10-53. It will be convenient to bring these numbers to
lower terms. And the simplest way is to suppose the oxygen
only to amount to one atom. If we calculate on this supposi-
tion we find, that the constituents of camphor will be,
Carbon, .* . 9-995 atoms, or 10 atoms.
Hydrogen, i.ii-j 8° do. 8 do.
Oxygen, . 1- do. 1 do.
Let us see how far the specific gravity of the vapour of cam-
phor will agree with this estimate,
10 volumes carbon weigh, 4' 16 67
8 volumes hydrogen, . 0*5555
•J- volume oxygen, ... . : 0*5555
5-2777
It gives us 5-2777 for the specific gravity, on the supposition that
the 19 atoms are condensed into one volume. But, as in most
organic vapours, the atoms are condensed, not into one, but into
two volumes, it is much more probable that the constitution
of camphor is C20 H16 O. The weight of these volumes would
be 10-5555, which, divided by 2, would give 5*2777, differing
but little from 5-337, found by Dumas.
These examples will give the reader a sufficient idea of the
way in which the atomic weight is deduced from the knowledge
of the specific gravity of the vapour of a body whose constituents
have been determined by analysis. This specific gravity ought
to amount to half the weight of the atoms of which the vapour is
composed. It must be acknowledged, however, that this mode
of coming at the atomic weight is only conjectural : for we can-
not assign any reason why the atoms making up the organic
body constitute not one volume, or three or four volumes, but
always two volumes. There doubtless is a reason for it, if the
APPENDIX.
G83
supposition be correct ; but at present it is out of our power to
assign any reason whatever,
Such was the state of the analysis of organic bodies when M.
Dumas, by an admirable series of experiments, demonstrated that
the atomic weight of carbon, as admitted by the continental che-
mists, from the experiments of Berzelius, namely, 0-76438, is
about 2 per cent, too high ; and that the true number is O75.*
To determine the exact composition of carbonic acid, MM. Du-
mas and Stas placed diamonds successively in a porcelain tube,
which was heated to redness, and a current of oxygen gas passed
through it till the diamond was converted into carbonic acid.
The oxygen passed previously through a tube filled with frag-
ments of pumice imbibed with caustic potash, and a second tube
filled with fragments of caustic potash, to deprive the oxygen
gas of every trace of carbonic acid with which it might happen
to be mixed. It then passed through a tube filled with frag-
ments of pumice impregnated with sulphuric acid, in order to
deprive it of any water which it might contain. Beyond the por-
celain tube was luted to it a long tube filled with oxide of cop-
per, which was kept in a state of ignition during the process, and
through which the surplus oxygen and the carbonic acid formed
all passed. To this was luted a tube bent like U, and filled with
fragments of pumice soaked in sulphuric acid, to imbibe any
water that might be formed during the combustion ; then a Lie-
big's tube containing caustic potash, then two tubes in U filled
with pumice impregnated with caustic potash, and lastly, a tube
in U filled with fragments of pumice impregnated with sul-
phuric acid, and finally, another tube containing potash in pow-
der. The whole apparatus is represented in the figure below.
It was ascertained by preliminary trials that, in this appa-
* Ann. de Chim. et de Phys. (third series,) i. 5. These experiments have
been repeated arid confirmed by Erdmann and Marchaiit. Ibid. iii. p. 500.
684 APPENDIX.
ratus, the whole carbonic acid formed during the combustion of
the diamonds was absorbed, and could be determined by weigh-
ing the several parts of the apparatus.
1471 parts of graphite being burned in this apparatus, the
carbonic acid formed was found to weigh 5395. Hence it is
composed of 2 oxygen -f O7497 carbon.
The diamond is much more combustible than graphite. The
quantity of hydrogen which it contained was not appreciable,
and certainly did not amount to T2Jooth °^ tne weight of the
diamond. The mean of five experiments on the combustion of
the diamond, in which the greatest quantity of diamond burnt
was 21*22 grains, and the least 10*926, gave for the composition
of the carbonic acid formed,
Oxygen, &»: 800* or 2
Carbon, &;* . 300*02 or 0*75005
It follows from these analyses of Dumas and Stas that the atomic
weight of carbon adopted by Liebig and his pupils in the labo-
ratory at Giessen is too high. Consequently, in all their ana-
lyses the quantity of carbon found by them in organic bodies is
too high, and consequently the quantity of oxygen too low.
Dumas has shown that in all these analyses a portion of the car-
bonic acid formed was allowed to escape. This partly compen-
sated for the excess of carbon calculated, and brought their re-
sults very near the truth. This loss of carbon took place in
four different ways.
1. The carbon is not completely consumed from the want of
oxygen.
2. The copper reduced is partly converted into carburet of
copper.
3. The liquid potash in Liebig's tube allows some of the car-
bonic acid formed to escape.
4. The air sucked through the apparatus carries off water
from the potash, and diminishes its weight.
These observations of Dumas leave no doubt that organic
analysis, in its present state, is incapable of giving results, the
accuracy of which can be fully depended on. To bring it to the
requisite state of precision he proposes the following amendments :
1. The quantity of organic matter analyzed should never be
less than 15 or 20 grains.
2. After the analysis is terminated, but while the decompos-
APPENDIX. 685
ing tube is still red hot, a considerable quantity of oxygen gas
should be passed through it, so as to burn all the charcoal depo-
sited, and to re-oxydize the copper, which has been reduced dur-
ing the process.
3. To collect all the water, besides a tube filled with chloride
of calcium, there should be another filled with pumice, charged
with sulphuric acid.
4. To collect all the carbonic acid gas, besides Liebig's potash
tube, there ought to be another filled with fragments of dry po-
tash, and another with fragments of pumice, charged with liquid
potash. The dry potash arrests the water with which the car-
bonic acid may be charged, in consequence of its passing through
the liquid potash in Liebig's tube.
After the oxygen gas has completed the combustion, and the
whole has been allowed to cool, a quantity of dry air is to be
passed through the apparatus to displace the oxygen gas, and
prevent any augmentation of weight which might otherwise ensue.
The analysis should be made slowly, and ought to occupy se-
veral hours.
Thus Dumas' process of analysis is the same as that of Dr
Prout, with some improvements, which enable him to weigh the
water and the carbonic acid formed. When rightly conducted
the results must be accurate, and of course, however often re-
peated, the same proportion of constituents must be obtained.
But Dumas' process enables us only to determine the weight of
carbon and hydrogen contained in the organic body analyzed.
When that body contains azote we must have recourse to the
process of Varrentrapp and Will, which has been already de-
scribed.
No. II.
TABLE OF THE ATOMIC WEIGHTS OF ANIMAL SUBSTANCES
AND OF THE VEGETABLE SUBSTANCES WHICH HAVE BEEN IN-
VESTIGATED BY CHEMISTS DURING THE YEARS 1839, 1840,
1841, AND 1842, OXYGEN BEING UNITY.
Atomic
A
Composition.
weight.
Abies excel sa resin, a .
C4°H29O6
39-625
Abies excelsa resin, b
C40H29O5
38-625
Acetate of oxide of amyle
C4H3O3-f- C10H1]LO
16-25
Acetate of methyle * ' V ! i
C4H303+C2H30
9-25
Acetic acid !• ? i i '»
C4H3O3
6-375
Aconitic acid .,., ^ ,
C8H4O8
14-5
Adipic acid . ,'.
C14H9O7
18-625
Albumen . • '''"...•'7
10(C40H31Az5O12)+Ph-f-S2
552-25
Albumen of silk
C54H44Az7O19
77-25
Alcohol
C4H5O + HO
5-75
Aldehyde . . -,..*'
C4H3O+HO
5-5
Allantoin . . .
C4H3Az2O3
9-875
Alloxane . . •
C8H4Az2O10
20-
Alloxanic acid
C8H2Az2O8+2(HO)
19.
Alloxantin . .
C8H5Az2O10
20-125
Amarythrin . ,..
C11H6O7
16-
Ambrein . . .
C33H32O
29-75
Amyle
CioHn
8-875
Anemonic acid
C7H5O6
11-875
Anemonin i-" v "
C7H3O4
9-625
Anilin .» , ; : . >,
C12H7Az
11-625
Anime resin , ... ;\
C40H32 + HO
35-125
Anisic acid
C16H605
17-75
Anisoin
C20H12Q2
18-5
APPENDIX.
687
Composition.
Atomic
weight.
Anisol
C14H7O-
13-375
An serin
C10HW
11-625
Anthracin
C30R12
24-
Anthranilic acid .
C14H6Az03
16.
Antiar resin
C4°H3°O2i
36-25
Anthracinase
C3°HnO
24-875
Anthracinese
C30H10O2
25-75
Anthracinise
C30H9O3
26-625
Anthracinose
C30H8O4
27-
Anthracinuse
C3'H7O5
28-375
Apoglucinic acid .
C18H11Q10
24-875
Aspartic acid
CGH5AzOG
14-375
Asphaltene
C19H15O3
19-125
Azalaic acid
C10H8O4
12-5
Azobenzide
C12H5Az+Aq
12-5
Azobenzoid
C42H16*Az2i
37-9375?
Azobenzoidin
C84H33Az5
75-875
Azobenzolid
C84H33Az5
75-875
Azotide of benzyle
C14H5Az
12-875
Azo-erythrin
C22H19AzO22
42-625
Azoleic acid
C13H13O4
15-375
Azolitmin
C17H12AzO10
26-?
Azomaric acid
C2°H9AzO6 + 2(HO)
24-375
B
Bdellium
C40H31O5
38-875
Benzamide
C14H5O2+AzH2
15-125
Benzene
C12H6
9-75
Benzhydramide
C42H18Az*
37-25
Benzilic acid
C28HllQ5_f_Aq
28-5
Benzimide
C28HuAzO4
28-125
Benzin
C12H6
9-75
Benzoate of hydret of )
benzyle . . f
C14H5O3+2(C14H6O2)+HO
41-75
Benzoate of oxide of 1
methyle . . J
C H O -f C H O
17-
Benzoene
C14H8
11-5
Benzoic acid
C14H5O3
14-125
Benzoin
C14H602
13-25
Benzoin resin, a .
C70H42O14
71-75
Benzoin resin, b .
C40H42O9
41-75
Benzoin resin, c .
C30H20Q5
30
Benzole
C12H6
9-75
Benzolon
CnH40
9-75
Benzone
C13H5O
11-375
Benzostilbin
C31H11O2
26-625
Benzyle
C14H5O2
13-125
Benzylic acid
C14H5O2
13-125
Betulin
C40H33O3
37-125
688
APPENDIX.
Composition.
Atomic
weight.
Bibromisatic acid
C16H3Br2AzO4+HO
39-25
Bibromisatide
C16H4Br2AzO* + S
40-25
Bibromisatin
C16H3Br2AzO4
38-125
Bichlorisatic acid . -
C16H3Chl2AzO4 + HO
28-25
Bichlorisatin . •
C16H3Chl2AzO4
27-125
Binitrobenzide
C14H4Az2O8
22-5
Binitrobenzoene . «
Bisulphate of amyle
2(AzO4)+CuH6
C10HUO+2(SO3)+HO
22-75
21-
Bisulphuret of ethyle
C4H5 S2
7-625
Botany Bay resin .
C40H20O12
44-5
Bromasinol
C20H9O2+Br3
48-125
Bromide of amyle
C10H11O4-Br
19-875
Bromide of benzyle
C14H5O2+Br
23-125
Bromide of cacodyle
C14H6Az2-j-Br
23-25
Bromide of methyle ,
C2H3Br
11-875
Bromide of salycyle .
C14H5O4Br
25-125
Bromisatin . v'i
C16H4BrAzO4
28-25
Bromobenzoic acid
2(C14H6O4)-f- HBr-f 2Aq
41-375
Bromocuminol . ._
C2°HnO2Br
28-375
Bromophenisic acid
C^H^^O-f-HO
41-375
Brucina . .
(M6JJ26Az2Q8
49-25
Butyric acid
C8H5O3
9-625
C
Cacodyle , <.•-,'
C4H6Az2
13-25
Cacodylic acid . .
C4H6Az2O4-fHO
18-375
Caffein . . . .
C12H6Az3O3
18-
Campholic acid
C20H17O3
20-125
Camphoric acid .
C10H7O3
11-375
Camphosulphuric acid .
C2°H13+S2O5
25-625
Cancrin
C16H13O4
17-625
Cantharidin . ..
C10H6O4
12-25
Carbazotic acid
C12H3Az3014(
27-625
Carbomethylic acid
C2O4+C2H!O
8-375
Carbovinic
CO2-fC4H5O
7-375
Carmin U
C*2H24AzO20
48-75
Casein i.. * ,
10(C4°H31Az5O12)-(-S
548-25
Catechuic acid
C2°H10O9
25-25
Cedrene !. . •
C32JJ24
27*
Cerebric acid
Cerosin L
3(C66H63AzO1<l)4.Ph
(^48050(^2
221-375
44-25
Cetene I. .
QlOOfjlOO
Cinchonina . . ,
C4°H24Az2O2
38-5
Cinnamein .
C54H26Q8
51-75
Cinnamen
C16H8
13-
Cinnamonic acid
C19H7O3
18-125
Cinnamonic ether
C18H7O3+C*H5O
22-
Citraconic acid
C5H«O3
7-
APPENDIX.
G89
Composition.
Atomic
weight.
Citric acid
C12H;)O11
20-625
Cocinic acid
£J27|-J27Q4
27-625
Codeina
Q35 {-{20 ^ZQ5
35-5
Collin
Cj3H10AzO5
19-5
Colophony
C40H30O4
37-75
Comenic acid
Ci2H2Os-f-2(HO)
19-5
Copal resin, b
C40H31O3
36-875
Chelidonina
C4°H20Az3O6
43-75
Chloracetic acid .
C4Chl3O3+HO
20-625
Chloranil
C12Chl2O2
20-
Chloranilic acid .
C12HChlO4 + 2(HO)
17-625
Chloretheral
C4H4ChlO
9-
Chloride of acetate of ox- 1
ide of methyle . J
C4HChl2O3-fC2H3O
18-
Chloride of aldehyden .
C4H3Chl3
16-875
Chloride of amyle
C10HnChl
10-375
Chloride of benzoen,
C14H3Chl6 + 3(HChl)
52-75
Chloride of benzole
C12H6 + Chl6
36-5
Chloride of benzyle
C14H5O2-f Chi
17-625
Chloride of chlorindopten
C12ChP+HO
32-625
Chloride of methyle
C2H3Chl
6-375
Chloride of salicyle
C14H5O4Chl
19-625
Chloride of strychnina .
C22H12AzChl2O5
33-75
Chloramital
C10H8^Chl1^O2
17-3125
Chloranthracinese
C30H10Chl2
32-75
Chlorindopten
C16H4Chl4O2
32-5
Chlorindoptic acid
C12H2ChPO+HO
24-875?
Chlormdalmite
C12H4ChPO2
25-
Chlorisatic acid
C16H4ChlAzO4-f-HO
23-875
Chlorisatide
CifiH5ChlAzO4+S
24-875
Chlorisatin
C16H4ChlAzO4
22-75
Chlorobenzide .
C12H3Chl3
22-875
Chlorocuminol
C20H11O2-f-Chl
22-875
Chlorohumic acid . . •
C32H12O16Chl
46-
Chloromenthen
C20H17Chl
21-625
Chloronaphthalic acid .
C23H6ChlO5 + HO
26-125
Chlorophenesic acid
Cl2H3ChPO + HO
20-5
Chlorophenesic acid
Cl2H2ChFO+HO
24-875
Chloroprotein
C4°H31Az5O12-f-Chl3
59-25
Chlorosalicin
C42H25O22Chl4
74-625
Chorosalicymide
C42H15Az2O6Chl3
56-375
Chloros-ulphuric acid
SO2Chl
8-5
Chlorovalerianic acid
C10H6Chl4O*
30-25
Chloroxalic ether
C2O3-|-C4Chl5O
31-
Chloroxamethan .
C8H2AzChP06
36-5
Choleic
C41H33Az012+2(HO)
50-875
Cholesteric .
C13H10Azi06
17-875
Cholesterin .
Q76JJ64Q2
67-
Choloidic
C32H25OG
33-125
XX
690
APPENDIX.
Composition.
Atomic
weight.
Chondrin
10(C32H25Az4O14-f S
484-5
Chrysamminic acid
C15HAz2O12
26-875
Chrysanilic acid
Chrysene
Chrysolepinic acid
Cinchovina .
C12H4
C12H2Az3O13+HO
C46H27Az2Os
30-75
9-5
28-625
49-375
Citric acid .
C12H5O11+3(HO)
24-
Conicina
C16H16Az
15-75
Creosote
C6H3O
5-875
Croconic acid
C5O4
7-75
Cubebin
C34H17O10
37-625
Cumene . ' • • '
C18H12
15-
Cuminic acid
C20HnO3
19-375
Cyanic acid .
Cyanodide of benzyle .
2(C2Az)O-fHO
C14H5O2+AzC2
8-625
16-375
Cyanodide of cacodyle .
C4H6As2-{-AzC2
16-5
Cyanogen
C2Az
3-25
Cyanuric acid v. . "
Cymene . • > '
6(C2Az)03+3(HO)
25-875
16-75
Cystic oxide •
C6H6AzO8
15.
D
Dallecochin
C3°H2°Az2O10
38-5
Diabetes sugar
C24H24O24+4(HO)
49-5
Dialuric acid . ,
CsH7Az3O8
20-125
Dragon's blood
C40H21O8
40-625
E
Eblanin
C21H904
20-875
Elaidic acid
C70H68Q8
69-
Elemi ....
C4°H33O
35-125
Erythrilin .
C22H16O6
24-5
Erythrin
C8H3O2
8-375
Erythroleic acid .
C26H22O8
30-25
Eristhrolein . . .
C26£J22()4
26-25
Erythrolitmin
C26H22Q12
34-25
Ethal . . . € •
C16H17O
15-125
Ether . . . J- .
C4H5O
4-625
Ethionic acid 5* .
S2Q5-fC4H40-fO
14-625
Ethyle .
C4H5
3-625
Euchronic acid
C12AzO6
16-75
Euphorbium resin
C4°H31O6
39-875
Eupion
C9H10
9-
F
Fibrin
10(C4°H31Az3O2)-r.Ph+S
550-25
Fibrin of silk
C38H31Az6O17
59-875
Fichtelite
C*H3
3-375
Fluoride of cacodyle
C4H6As6Fl
14-5
4
APPENDIX.
691
Composition.
Atomic
weight.
Formethylite
C8H10O6
13-25
Formic acid .
C2HO3
4-625
Formic ether
C2HO3+C4H5O
9-25
Formobenzoilic acid
C1*H5O»+CJHO3+ Aq
17-875
Fossil wax of Gallicia .
CXHX
Fulminic acid
4(C2Az)O24-2(HO)
17-25
Fumaramide
C*H02+AzH2
7-125
Fumaric acid
C*HO3
6-125
G
Gallic acid .
C7HO3
8-375
Gamboge (resin of)
C82H5O20
86-25
Gelatin from silk .
C19H15Az3O7
28-375
Glucinic acid
C8H5O5
11-625
Guaiacum resin
C*°H23O10
42-875
Garanina
C12H'AZ3O3
18-
Guyoquillite
C2OH13O3
19-625
H
Harmalina .
C2*H12Az2+HO
24-125
Hatchettine
CTHX
Helenin
C15H1002
14-5
Hematosin .
£H4£J22Az3Q6
50-5
Hippuric acid
C18H8AzO5
21-25
Hippuric ether
C18H8AzO5+C4H5O
25-875
Humic acid .
C40H12O12
43-5
Humin
C40H15015
46-875
Hydrate of phenyle
C12H5O + HO
11-75
Hydrated oxide of amyle
CleHnO+HO
11-
Hydret of azobenzoilin
C42H18Az2
37-25
Hydret of benzoilin
fC«H18Off
1C14H6O2
39-75
13-25
Hydret of benzyle
CUH6O2
13-25
Hydret of sulphazobenzoil
C126H54Az2S12
130-75
Hydret of sulphobenzoil
C14H6S2
15-25
Hydrobenzamide .
C22H18Az2
37-25
Hydrochlorate of chloride )
of amyle . . J
C10H3ChP
48-375
Hydromelonic acid
C6HAz*+4(HO)
16-125
Hydrotelluric ether
C*H5F12
11-625
Hydrous aspartic acid .
C8H5AzO6+2(HO)
16-625
Hydrous citric acid
C12H5On+3(HO)
24-
Hydrous gallic acid
C7HO3+2(HO)
10-625
Hydrous mellitic acid
C4H3+HO
7-125
Hydrous mucic acid
C12H8O14-f-2(HO)
26>25
Hydrous subchloride of)
cacodyle . . J
C4H6As2+Chl + HO
18-875
Hydrous tannic acid
C18H5O9 + 3(HO)
26-5
Hydrous tartaric acid .
C8H*O10+2(HO)
18-75
692
APPENDIX.
Hypobenzylic acid
Hypo-sulpho benzydic acid
Jalap resin .
Idrialin
Jervina
Indigogen .
Indigotic acid
Indigotin
Inulin
Iodide of amyle
Iodide of benzyle
Iodide of cacodyle
lodosalicylic acid .
Isatic acid
Isatide
Isatin
Itaconic acid
K
Kalisaccharic acid
Kinic acid
Labdanum .
Lactic acid
Lecanorin
Lignin •
Lipic acid
Lithofellic acid
M
Malic acid .
Mannite
Margaric acid
Margarin
Mastich resin, a
Mastich resin, b
Meconic acid
Melanic acid
Melanochin
Mellitic acid
Menthene
Mercuriobromide of ox-
ide of cacodyle
Mercuriochloride of ox-
ide of cacodyle
Mesite
Composition.
Atomic-
weight.
C14H5O12
12-625
acid
C12H5O5S2+HO
20-125
C40H34O20
54-25
:
C15H5
11-875
CGOH45Az2O5
59-125
CI6H6AzO2
16-5
:
C14H4AzO9
21-75
.
C16H5AzO2
16375
£24JJ21Q2I
41-625
:
C^H^O+Io
25-625
Cl4H5O2-f lo
28-875
C4H6As2 + Io
29-
:
Ci4H5O4+Io
30-875
C16H5AzO4+2(HO)
20-625
C16H6AzO4
18-5
C16H5AzO*
18*375
C5H2°3+H°
8-125
Ci8Hi5Oi*
30-375
C14H8O8
19-5
C40H53Q7
41-125
C6H3O4
8-875
C18H8O8
22-5
C18H9O9
19-125
m
C5H3O4+HO
9-25
•
C42H3808
44-25
C8H4O8
14-5
C24H28024
45-5
(^54 f|33Q3 _|_ HO
33-75
£33pJ53Q
29-875
C4°H31O4
37-875
C40H51O2
35-875
C14HOn + 3(HO)
25-
B
C10H4O5
13-
C24H18 A z1 O12
36-375
t
C4O3
6-
.
Q21JJ18
18-
ox-
C4H6As2O + Hg2Br2
59-25
DX-
C4H6As20 + Hg2Chl2
48-25
'/
C6H7Q3
8-375
APPENDIX.
693
Composition.
Atomic
weight.
Mesoxalic acid
C3O4
6-25
Metameconic acid
C12H208-|2(HO)
17-25
Metacinnamein
C18H8O2
16-5
Metanaphthalin
P28f J12
22-5
Methylal
Q12£|8Q4
14-
Methyle
C2H3
1-875
Middletonite
Q20JJ11Q
17-375
Micomelic acid
C8H5A 4O5
18-625
Morphina
C35H20AzO6
36-5
Mucic acid .
C12H8O14
24-
Murexane
C6H4Az2O5
13-5
Murexide
C12H6Az5O8
26-5
N
Naphtha
C14H13
12-125
Naphthalic acid
C16H4O6
18-5
Naphthene .
C16H16
14-
Naphthol
C24H20
20-5
Naphtholin .
C28H11
22-375
Narcotina
C44H23AzO13
50-625
Nicotina
L10H8Az
10-375
Nigric acid .
C14H7O7
18-375
Nitro-anisic acid .
C16H605+Az05
25-
Nitro-aniside
C20H10Az2QlO
29-75
Nitro-benzide
C12H5 + AzO4
15-375
Nitrobenzoic acid
C14H5Az08
20-875
Nitronaphthalase .
C10H?AzO4
14-125
Nitronaphthalese .
C20H6Az2O8
27-25
Nitronaphthalic acid
C12H5AzO12
23-375
Nitronaphthalise .
C20K5Az3Ql2
32-875
Nitrophenesic acid
Nitrophenisic acid
Nitrophloretic acid
C12H3(Az04)20+HO
C12H2(AzO4)3O + HO
C3oH'*AzO13
23-
28-625
40-75
Nitrosalicylic acid
C'4H504 + AzO*
20-875
0
Oil of anise
C2°H1O2
18-5
Oil of ants .
C5H2O2
6-
Oil of Artemisia sanctonic
C18H.5Q2
17-375
Oil of asarum
Q'H'O
6-875
Oil of assafcetida
fC5°H45O4S5
}C95H89O20S10
58-125
22-375
Oil of bitter almonds
C14H6O2
13-25
Oil of bergamotte
CioH8
8-5
Oil of cajeput
Ci0H9O
9-625
Oil of camphor
ClliinO
12-875
Oil of cascarilla
rc24Hi8o
21-25
1 0 ^ 4H ^ ^ O
12-875
Oil of cedar
C32H2tiO2
29-25
694
APPENDIX.
Composition.
Atomic
weight.
Oil of cinnamon
Q20JJ1 1Q2
18-375
Oil of cloves
C24H15O5
24-875
Oil of copaiva
CioHs
8-5
Oil of cubebs
C15H12
12-75
Oil of elemi
C10H8
8-5
Oil of fennel
C15H12
12-75
Oil of hyssop ...
C60H47O
51-875
Oil of juniper
C15H12
12-75
Oil of lavender
C12H10O
11-25
Oil of laurel
C2°H16
17-
Oil of lemons - •
C10H8
8-5
Oil of mace
C16HI3O
14-625
Oil of marjoram .
C50H40O
43-5
Oil of mustard
C4lH25Az4S10
60-875
Oil of olibanum
C35H28O
30-75
Oil of orange flowers
C10H8
8-5
Oil of orange peel
C10H8
8-5
Oil of parsley
C10H8
8-5
Oil of pennyroyal
C15H14O2
15-
Oil of pepper
C13H10
11-
Oil of peppermint
rci2Hioo
11-25
23-5
Oil of rosemary
P45U38Q2
40-5
Oil of roses .
Q23JJ23Q3
23.125
Oil of rue . .
C23H28O3
27-5
Oil of sabine . ,. '
C20H16
17-
Oil of Spiraea ulmaria
C11H5O3
10-875
Oil of turpentine . . N.
C20H16
17-
Oenanthylic acid . -*
C14H13O3
15-125
Oleic acid
C44H39O4-f-HO
43-
Orcein, a *
C18H10-f- AzO5
21-5
Orcein, (3 . {- i <«-H
Cl8H10AzO8
24-5
Orcin
C16H6O2
14-75
Oxalate of oxide ofmethyle
C2O3+C2H3O
7-375
Oxalhydric acid
Ci2H5Ou
20-625
Oxalic acid
C2O3
4-5
Oxaluric acid
C6H4Az208
16-5
Oxiodide of cacodyle
Oxide of amyle
C4H6 As2O + 3(C4H« Aslo)
C10H"O
101-25
9-875
Oxide of benzyle . .
C14H5O
12-125
Oxide of cacodyle
C4H6Az2O
14-25
Oxide of methy le
C2H3O
2-875
Oxybromide of cacodyle
C4H6As2O+3(C4H6As2Br)
84-
Oxychloride of cacodyle
Oxyprotein
(C4 HS As2O+3(C4H6
\ As2Chl)
C4°H31Az5Ol5+HO
67-5
58-75
Ozocerate
CXHX
P
65-5
APPENDIX.
695
Composition.
Atomic
weight.
Parabanic acid
C^H^Az'^O6
14-25
Paraffin
C20H21
17-625
Paramide
C8HAz04
11-875
Paranaphthalin
C30H12
24-
Paratartaric acid
Peat, resin, a
C8H4010+li(H°)
C50H40O9
18-1875
51-5
Peat, resin, b
f^nu6if)o
75-125
Peat, resin, c
(^ 1 04tr94/~)9
98-75
Peat, resin, d
C131H121O9
122-375
Peat, resin, a
C35H2SO5
34-75
Peat amma resin .
f>l90TT84f^6
84-
Pectic acid .
{** 1 1 W^O 1 0
19-125
Perchloric ether
ChlO7+C4H50
16-125
Peristerin
C4H3O
4-375
Petrolene
CJ20JJ16
17-
Peruvin
C18H12O2
17.
Phene
C12H6
9-75
Phenyle
C12H5O
10-625
Phloretin
C4]H21 O14
48-125
Phlorizein
(2J42JJ30Q24_|_j^z2Q3
65-75
Phlorizin
C42H21Q16
50-125
Phosphoric acid
Ph2O5
9-
Pimaric acid
C20H15Q2
18-875
Pimelic acid
C7H503+HO
10-
Piperina . . - 4
C3*H10AzO6
35-625
Polychrom
C8H4^O5
11-5625
Polygalic acid
C9H806
15-75
Potassio cuminol .
C20HnO+K
23-375
Protein
C48H36Az6O14
65-
Protonitro benzoene
AzO4-f-Cl4H7
17-125
Pseudacetic acid .
9-15
Pyrene
C10H4
8-
Pyrocatechin
C6H20 + HO
6-875
Pyromaric acid
C20H15O
18-875
Pyromeconic acid
C10H3O5 + H
14-
Pyruric acid
C4H8AzO5
10-75 ?
Q
Quercitric acid
C16H9O10
23-125
Quiniria
C40H24Az204
40-5
R
Resin of indigo
C40H16Chl4O10
61-75
Resin of tolu
C18H10Q5
19.75
Retinaphtha
C14H8
11-5
Retinasphalt
C7H5O
6-875
Retinol
C32H16
26
Retinyle
C18H12
15
Rhodizonic acid
c^o5
7-25 ?
696
APPENDIX.
Composition.
Atomic
weight.
Rhubarbaric acid .
(J55U19Q19
47-C526
Rusiochin .
C24H3°Az2O16
41.25
S
Saccharic acid
C12H5OH
20625
Sagapenum .
C4°H29O9
42-625
Salicin
C42H19O22
55-875
Salicylic acid
Salicyle
C14H5O4
16-125
15.125
Salicyle, hydret of
Salicon
C42H25O7
15-25
41-625
Salicylimide *
C42H18Az2OG
43-25
Saliretin
C H O'-|-HO
32-5
Sandarach, resin, a .
C40H31O5
38-875
Sandarach, resin, b
C40H31O6
39-875
Sandarach, resin, c
C40H30O6
39-75
Scammony resin .
Sebacic acid
C10H8O3
54-25
11.5
Seleniet of cacodyle
C4H6As2+Se
17-75
Semichloret of ether
C4H4ChlO
9
Sericic acid
C28H28O4
28-5
Sinapolin
C28H25Az4O4
35.125
Spanolitmin
C18H7Q16
30-375
Starch
C12H9Q9
19-125
Stearic acid
C68H66O5-f 2(HO)
66-5
Stearopten of oil of ber \
C3HO
3.375
gamotte . . j
Stearopten of oil of lemons
C2H2O
2-75
Stearopten of oil of mace
C16H16Q5
19
Stearopten of oil of mar- 1
C14H15Q5
17-375
joram . . . j
Stearopten of oil of pep- 1
C21£J20Q2
20-25
permint ,. . .)
Strychnina .
C42H22Az2O4
41.75
Styracin
C18H1102
i'1-375
Styrole .
C12H6
9-75
Suberic acid
C8H6O3-f-HO
10-875
Succinic
C4H2O54-HO
7-375
Succino-sulphuric acid .
C8H4O6+2(HO)+2(SO3)
24-75
Sugar, common «
C24H18Q18
38-25
Sugar, grape
C24H24O24-f 4(HO)
49-5
Sugar, jelly
C16H18Az4O14
35-25
Sugar of milk
C24H20O20-f-2(HO)
42-75
Sulphamilic acid .
SO3 + C1°H11O4-HO
9
Sulphethyl-sulphuric acid
C4H5O4S2
11-625
S"lphindilic acid .
C16H4AzO+SO3
20.25
Sulphisatin ,
C16H5AzO2 + S3
22-5
Sulpho-amylate of bary tes
O3-j-BaO) + HO /
23-5
APPENDIX.
697
Composition.
Atomic
weight.
Sulphobenzide
Sulphobenzoenic acid
C12H5O2S
C14H10+S205
15-125
20-75
Sulphobenzoic acid
Sulphobiproteic acid
j2(C40H31Az5O12)-f SO3
1 +2(HO)
24-375
116-5
Sulphocumenic acid
Cl8Hl2+S2O5
29-
Sulphohelenic acid
Sulphohydret of azobenzoil
C15H10O2+SO3+HO
C42H18Az2S3
20-625
43-25
Sulphophenic acid
C12H5O + 2(S03)H-HO
21-75
Sulphoproteic acid
C40H31Az5O12-}-SO3
59-625
Sulphopurpuric acid
C32H10Az2O*+2(SO3)
42-75
Sulphoretenilic acid
Ql8f^l2 i C2Q5
24-
Sulphuret of benzyle
p!4£j5Q2 j Q
15-125
Sulphuret of cacodyle .
C*H6As2+S
15-25
T
Tannin
C18H5O9
23-125
Tartaric acid
C8H4O10
16-5
Tartralic acid
C8H*O*°.fli(HO)
18-1875
Tartrelic acid
C8H4O10+HO
17-625
Terethrin
C2 H10O19
36-75
Theobromin
C9H5Az3O2
14-625
Theina
C12H6Az3O3
18-
Thionuric acid
C8H5Az3O6-j-2(SO3)
27-875
Tolene
C13H10
11-
UV
Valerianic ether .
C10H9O3-j C4H5O
16-25
Veratric acid
C18H1008
22-75
Ulmic acid
C4°H14O12
43-75
Ulmin . .
C40H16Q4
36-
Uramile
C8H5Az3O6
17-875
Uramilic acid
C16H10Az5O15
37-
Urea
C2H4Az2O2
7-5
Uric acid
C9Az2O*-f C2H4 Az?O2
21-75
Uric oxide
C5H2Az2Q2
9-5
X
Xanthic oxide
C5H2Az2O2
9-5
Xantlioproteic acid
C34fJ24.Az4O14-J_2(HO)
52-
Xylite
C4H5O2
5-625
INDEX.
ACID, adipic, page 19
alloxanic, 45
ambreic, 27
azelaic, 22
azoleic, 22
bombycic, 27
butyric, 26
capric, 26
caproic, 26
castoric, 27
cerebric, 69
chlorobiproteic, 174
chloroproteic, 176
choleic, 59
cholesteric, 62
cholic, 15
choloidic, 13
dialuric, 50
formic, 7
hippuric, 59
hircic, 26
hydromelonic, 66
lactic, 9
lipic, 21
lithic, 31
lithofellic, 22
mesoxalic, 4
mycomelic, 48
nitroleucic, 73
of ants, 7
of milk, 9
oxaluric, 42
parabanic, 40
phocenic, 26
pimelic, 18
pyrozoic, 16
pyruric, 38
sebacic, 12
suberic, 11
succinic, 9
sulphoproteic, 73
thionuric, 53
uramilic, 56
uric, 30
xanthoproteic, 178
Adipic acid, 19
Air in swimming bladder of fishes, 550
Albumen, page 180
of blood, 358
from silk, 184
Allantoin, 107
Allan tois, liquor of, 531
Alloxane, 111
Alloxanic acid, 45
Alloxantin, 115
Ambergris, 150
Ambreic acid, 27
Ambrein, 150
Amides, 98
animal, 167
Ammolin, 90
Ammonia, 97
Ammonium, 100
Amnios, 526
Animal acids, 2
destitute of azote, 4
bases, 75
colouring matters, 157
poisons, 537
principles, 2
Animals, functions of, 586
liquid parts of, 349
solid parts of, 233
Animin, 87
Anserin, 165
Aposepedin, 93
Arachnoid membrane, 266
Arteries, 316
Assimilation, 651
Azelaic acid, 22
Azoleic acid, 22
Azote in organic bodies, how determined,
667
B
Bases, animal, 75
Beist, 429
Bezoars, 582
Bicuspid teeth, 243
Bile, 406
Biliary concretions, 574
Blood, 349
specific gravity of, 355
in various animals, 382
diseases, 373
700
INDEX.
Bombycic acid, page 27
Bone of cuttle-fish, 259
Bones, 233
Brain, 265
structure of, 266
Breasts, 319
Bristle, 301
Butter, 431
Butyric acid, 26
Calculi, ammonia-phosphate of magne-
sia, 559
carbonate of lime, 559
cystic oxide, 561
ferruginous, 563
fibrinous, 562
fusible, 559
lithofellic, 585
mulberry, 560
origin of, 563
phosphate of lime, 558
urate of ammonia, 558
urate of soda, 561
uric acid, 557
urinary, 553
of inferior animals, 566
xanthic oxide, 562
Cancrin, 163
Canine teeth, 243
Cantharidin, 156
Capric acid, 26
Caproic acid, 26
Capsule of teeth, 245
Carbon in organic bodies, how ascertain-
ed, 663
Carmin, 158
Cartilage, 250
Casein, 185
Castor, 148
Castoric acid, 27 ^a'
Castorin, 148
Cellular substance, 291
Cerebellum, 265
Cerebric acid, 69
Cerebrum, 265
Cerumen, 516
Cetene, 148
Cheese, 433
Chitin, 97
Chloroproteic acid, 175
Choleic acid, 59
Cholesteric acid, 62
Cholesterin, 152
Cholic acid, 15
Choloidic acid, 13
Chondrin, 211
Choroid coat, 336
Chyle, 413
Cochineal, 158
Collin, 201
Colostrum, 428, 435
Concretions, biliary, page 574
gouty, 570
intestinal, 580
morbid, 552
salivary. 571
Conjunctiva, tunica, 335
Coral, 263
Corium, 293
Cornea, 336
Cow, respiration of, 622
Crabs, colouring matter of, 163
Cream, 429
Crimping, 286
Crusta petrosa, 245
Crusts, 260
Crystalline lens, 92
Curd, 433
Cutis, 293
Cuttle-fish bone, 259
Cyanogen and its compounds, 28
Cyanurin, 489
Cystin, 105
D
Diabetes, 482
sugar, 129
Dialuric acid, 50
Digestion, 586
Dippel's animal oil, 83
Duck's fat, 139
Dura mater, 266
E
Ear-wax, 516
Egg, white of, 447
shells, 446
Eggs of fowls, 446
Enamel of teeth, 245, 246
Epidermis, 298
Erythric acid, 111
Ethal, 147
Eye, liquids of, 512
membranes of, 335
of birds, 515
of horse, 515
of man, 515
of oxen, 515
of sheep, 513
F
Fat of Coccus cacti, 141
Delphinus globiceps, 140
duck, 139
goat, 137 +r
goose, 138
man, 137
porpois, 140
turkey, 139
Feathers, 305
Feces, 542
human, 542
Fibrin from blood, 192, 359
silk, 198
INDEX.
701
Fishes, respiration of, page 620
air in swimming bladders of, 550
Flesh, 273
Food, 587
digestibility of, 589
Formic acid, 7
Fuscin, 91
G
Gastric juice, 393, 598
Gelatin, 201
from silk, 217
Glands, lachrymal, 332
salivary, 330
sublingual, 331
submaxillary, 330
Globulin, 221
Globules of the blood, 355
Goat's fat, 137
Goose fat, 138
foot, colouring matter of, 165
Gorgonia, 264
Gouty concretions, 570
H
Hair, 301
Harts horn, 312
Heat, animal, 626
source of, 631
Hematosin, 219
Hippuric acid, 59
Hircic acid, 28
Hog's lard, 134
Horns, 306
Horse, respiration of, 623
Human fat, 137
Hydrogen inorganic bodies, how deter-
mined, 665
Hydromelonic acid, 66
I
Incisors, 243
Intestinal concretions, 580
Ivory, 244, 247
K
Kidneys, action of, 643
cortical portion of, 320
medullary portion of, 320
Koumiss, 436
L
Lachrymal gland, 332
Lactic acid, 9
Leather, 294
Ligaments, 289
Lipic acid, 21
Liquids of the eye, 512
Liquor of blisters, 420
dropsy, 422
Lithic acid, 31
Lithofellic acid, 22
calculi, 585
Liver, 320, 407
actions of, 603
Lungs, 333
Lymph, 416
M
Mackerel, digestion of, 597
Madrepores, 262
Mammae, 319
Margaric acid, 142, 144
Margaron, 146
Marrow, 253
Melain, 126
Melanic acid, 491
Membrana putaminis, 446
Membranes, mucous, 314
serous, 313
Mesoxalic acid, 4
Milk, 424
ass's, 440
ewe's, 445
goat's, 444
mare's, 444
woman's, 438
Millepores, 262
Milt of the carp, 501
Molar teeth, 244
Mucous membranes, 314
Mucus, 506
of bronchiae, 508
of gall-bladder, 510
of mouth, 507
of nose, 507
of stomach and intestines, 509
Murexane, 124
Murexide, 119
Muscles, 273
structure of, 273
Mutton suet, 136
Mycomelic acid, 48
N
Nails, 311
Nerves, 265
Nitroleucic acid, 73
0
Odorin, 63
Olanin, 88
Oonin, 128
Organic bodies, method of analyzing, 659
Osmazome, 178
Ossification, 578
Otin, 518
Oxaluric acid, 42
Ox fat, 135
Oxides, animal, containing azote, 102
not containing azote and
not oily, 126
oily, saponifiable, 134
oily, not saponifiable, 1 45
Pancreas, 320, 403
Pancreatic juice, 403
Pancreatin, 232
Parabanic acid, 40
Parotid glands, 330
702
INDEX.
Pearl, page 259
Pepsin, 229
Peristerin, 164
Perspiration, 519, 648
Phocenic acid, 26
Pia mater, 266
Pigeon, digestion of, 597
Pigeon's feet, colouring matter of, 164
Pimelic acid, 18
Poisons, animal, 537
Porpoise fat, 140
Protein, 168
Ptyalin, 228
Pulp of tooth, 244
Purple dye, 166
Pus, 534
Putaminis, membrana, 446
Pyrozoic acid, 16
Pyruric acid, 38
R
Rabbit, digestion of, 596
Ranula, liquid of, 392
Respiration, 604
Rete mucosum, 300
Ricottin, 200
Roe of fishes, 455
Saliva, 383
human, 383
of inferior animals, 387
Salivary concretions, 571
glands, 330
Salivin, 228
Scales, 311
Sclerotic coat, 335
Sebacic acid, 12
Semen, 226, 499
Sericin, 161
Serous membranes, 313
Serolin, 155
Shells, 256
mother of pearl, 257
oyster, 258
porcelaneous, 257
Silk, 339
colouring matter of, 161
Skin, 292
Soapy matter of urine, 75
Spermatin, 226
Spider's webs, 346
Sponges, 265
Stearic acid, 142
Stearin, 142
Stevens, Dr, experiments on digestion
by, 593
Suberic acid, 1 1
Sublingual glands, 331
Submaxillary glands, 336
Succinic acid, 9
Sugar of diabetes, 129
milk, 133
Sulphoproteic acid, 173
Sweat, page 523
Swimming bladder of fishes, air in, 550
Synovia, 502
T
Tanning. 294
Taurin, 95
Tawing, 297
Tears, 507
Teeth, 243
Temperature of animals, 628
Tench, digestion of, 597
Tendons, 288
Testes, 331
Thionuric acid, 53
Tubuli seminiferi, 331
uriniferi 327
Tunica albuginea, 331
Turkey fat, 139
V
Vapour, specific gravity of, how deter-
mined, 678
Vasa eiferentia, 332
Veins, 318
U
Uramile, 118
Uramilic acid, 56
Urea, 75
Uric acid, 30
Uric oxide, 31, 103
Urinary calculi, 552
Urine, 459
in disease, 477
of ass, 494
of beaver, 497
of camel, 495
of cow, 494
of dog, 493
of elephant, 497
of fowls, 498
of guinea-pig, 496
of horse, 493
of monkey, 493
of rabbit, 496
of rhinoceros, 496
of serpents, 498
of sow, 496
W
Whale oil, 139
Whey, 434
float, 435
White of egg, 447
Wool, 305
X
Xanthic oxide, 103
Xanthroproteic acid, 178
Yolk of egg, 447
Zomidin, 283
Zoophytes, 262
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