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BULLETIN

OF THE

UNIVERSITY OF WISCONSIN

SCIENCE SERIES

L Y

VOLUME 2
(1897-1901)

WILLIAM HERBERT HOBBS, PH. D., Editor
Professor of Mineralogy and Petrology

PUBLISHED BY AUTHORITY OF LAW AND WITH ;THE APPROVAL OF THE
REGENTS OF THE UNIVERSITY

MADI.SON, WIS.

PUBLISHED BY THE UNIVERSITY

1901

COMMITTEE OF PUBLICATION

OF THE

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

CHARLES KENDALL ADAMS, LL.D., President of the University
WILLIAM H. HOBES, Ph. D., Editor-in-Chief

EDITORS

Richard T. Ely, Ph. D., Director of the School of Economics and Political Science
Editor of the Econoniics and Political Science Series

William H. Hobbs, Ph. D., Professor of Mineralogy and Petrology
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CONTENTS OF VOLUME 2.

Page.

No. 1. The action of solutions on the sense of taste, by Louis Kahlen-

berg, Assistant Professor of Physical Chemistry 1

No. 2. Aspects of mental economy, by M. V. O'Shea, Professor of

the Science and Art of Education 33

No. 3. Contributions from the Anatomical Laboratory of the Uni-
versity of Wisconsin, by William S. Miller, Assistant Pro-
fessor of Vertebrate Anatomy 199

No. 4. The Anomalous dispersion of cyanin, by Carl Edward

Magnusson, Fellow in Physics 247

No. 5. The theory of electrolytic dissociation as viewed in the light
of facts recently ascertained, by Louis Kahlenberg, Pro-
fessor of Physical Chemistry, with the co-operation of
Arthur A. Koch and Roy D. Hall, Assistants in Chem-
istry 297

No. 6. On the dielectric constants of pure soivents, by Herman

Schlundt, Instructor in General and Physical Chemistry. 353

INDEX TO PLATES.

Opposite page

Plate 1 and 2. Graphic representation of the results of the chemical

examination of salivary and gastric digestion 140

Plates 3-8. Lung of Necturus 210

Plates 9-11. Vascular system of Necturus 226

Plates 12-13. Brain of Necturus '. 234

Plates 14-15. Peritoneal epithelium of the cat 246

Plates 16-22. Anomalous dispersion of cyanin 296

PB1CB 35 CENTO

BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 35.

SCItNCI SCRIES. VOL. 2, NO. 1, Pp. 1-31.

THE ACTION OF SOLUTIONS ON THE SENSE OF TASTE

BY

LOUIS KAHLENBERG, Ph. D.

Assistant Professor of Physical Chemistry.

Published bi-monthly by authority of law with the approval of the Regents

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
September, 1898

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CHARLES KENDALL ADAMS, President of the University

WILLIAM HERBERT HOBBS, Editor-in-Chief

EDITORS

Frederick Jackson Turner, Economics, Political Science, and History
Charles Forster Smith, Philology and Literature.
William Herbert Hobbs, Science
Nelson Oliver Whitney, Engineering

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

ScuNci Skmiks, vol 2, no. I, Pp. 1-31.

THE ACTION OF SOLUTIONS ON THE SENSE OF TASTE

BY

LOUIS KAHLENBERG, Ph. D.

Assistant Professor of Physical Chemistry.

LIBRARY
NEW YORK
BOTANICAL

MADISON, WIS.
July, 1898

THE ACTION OF SOLUTIONS ON THE SENSE OF TASTE.1

Introduction.

In order to be capable of affecting the sense of taste a sub-
stance must be soluble to a certain extent in the saliva, which
is, in most cases at least, the same as saying that it must be solu-
ble in water. Substances that are practically insoluble can
when introduced into the mouth produce only sensations of tem-
perature and of touch. The fact that a substance is soluble in
water is not of itself sufficient, however, to enable it to cause
sensations of taste, for there are many substances that are quite
soluble in water and yet their solutions possess very little or no
taste. It is evident that the effect of a solution on the sense of
taste depends upon the concentration of the solution, the chem-
ical nature of the dissolved substances, and the conditions in
which the latter exist in the solution.

Investigations on the subject of solutions have been vigorously
pushed during the last ten years by workers in the field of physi-
cal chemistry, and as a result of their labors we have today a
far better understanding of the condition in which a substance
exists when dissolved than ever before. Indeed, van't Hoff's1
theory of solutions and Arrhenius'2 theory of electrolytic dis-
sociation have practically solved the mystery that has hereto-
fore engrossed the whole subject of solutions.

Since substances must be dissolved in order to be tasted, and
since the taste of a solution depends upon the nature of the dis-
solved substance and its molecular condition when in solution,

'Read before the Wisconsin Academy of Sciences, Arts, and Letters at its
meeting at Milwaukee, December, 1897.
2Zeitschr. f. physik. Cbem. 1, 481, 1887.
3 Ibidem, 1, 631, 1887.

4 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

it was thought that a systematic study of the effect of solutions
on the sense of taste, pursued in the light of the knowledge that
has in recent years been gathered concerning the subject of so-
lutions, would more clearly define the nature of the substances
that produce certain tastes and possibly also indicate the mode
of action by means of which these substances cause the sensa-
tions of taste. The present investigation is an attempt to study
the effect of solutions on the sense of taste in the light of the
modern theories of the nature of solutions.

The Nature of Aqueous Solutions.

Aqueous solutions may be divided into two classes, those that
are practically non-conductors of electricity and those that con-
duct electricity readily. The former are generally termed non-
electrolytes and the latter electrolytes. The aqueous solutions
that practically do not conduct electricity are those of substances
that possess neither acid, basic, nor salt-like character, or at least
they possess these characteristics only to a slight degree. Into
this category belong, for example, solutions of the mono- and
polyatomic alcohols, the sugars, the esters, very weak acids and
bases, colloidal substances, and other ccmpounds generally
spoken of as neutral1 substances. The solutions that conduct
electricity readily are those of compounds of pronounced acid,
basic, or salt-like character. This class includes solutions of all
the acids, bases, and salts except e )me very weak acids and bases
and the salts formed by their combination.

Measurements of the osmotic pressure, the lowering of the
freezing point, and the elevation of the boiling point of solutions
of non-electrolytes have shown that generally the dissolved sub-
stances contained in these solutions exist in the simple molecular
condition that is expressed by their chemical formulas as usually
written; in other words, the molecular weight of these substances
when in the dissolved condition is that which is generally
ascribed to them. When it is possible to find the molecular
weight of a non-electrolyte by a vapor density determination as

1The term neutral substances as used here does not include salts.

KAHLENBERG — ACTION OF SOLUTIONS ON TASTE. 5

•well as from the osmotic pressure, the freezing point, or the
boiling point of its solution, the results are generally identical.
Instances where double or even more complex molecules are
formed when substances are dissolved in water are known, and
yet these are perhaps not much more common than cases of
polymerization in the gaseous state. The analogy that exists be-
tween gases and solutions of non-electrolytes is almost perfect.
This appears clearly when we regard the statement of Avogadro
— equal volumes of all gases under the same conditions of tem-
perature and pressure contain an equal number of molecules —
in conjunction with this statement modified through the work
of van't HofT so as to apply to solutions, — equal volumes of so-
lutions having the same temperature and the same osmotic pres-
sure contain an equal number of molecules, which number is
identical with that contained in a gas having tha same volume
and temperature as the solution and a pressure equal to the os-
motic pressure of the latter.

The solutions that conduct electricity on the other hand are
different in character. From what has been said, it is clear that
these solutions are such as contain the ordinary salts, acids, and
bases. These substances do not exist in aqueous solutions in the
molecular condition represented by their chemical formulas as
ordinarily written. The osmotic pressure, the lowering of the
freezing-point, and the elevation of the boiling-point of these
solutions are all greater than they would be if the substances
when in solution possessed the molecular weight indicated by the
usual formulae. According to the theory of Arrhenius these
substances exist in solution in a partially dissociated state; this
explains the peculiar behavior of these solutions as compared
with those of non-electrolytes. The degree or extent of this
dissociation depends on the nature of the dissolved substance and
the concentration of the solution. Theoretically the dissocia-
tion is complete only at infinite dilution; many substances, how-
ever, are so strongly dissociated when dissolved in water that
dissociation is practically complete at finite dilutions. The part-
molecules into which the dissolved molecules are dissociated are

6 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

termed ions. These ions migrate through the solution under
the influence of the electric current, whence their name. The
conduction of electricity by the solution depends upon the pres-
ence and the movements of the ions. Those ions that travel
toward the negative pole are considered as charged with positive
electricity and are termed cathions, while those that move toward
the positive pole are called anions and are charged with nega-
tive electricity. The number of cathions in a solution is always
equivalent to the number of anions present, so that electrical
neutrality of the solut:on is preserved. Thus in the case of so-
dium chloride the ions are Na and CI, and any solution of this
salt contains these ions together with a certain amount of un-
dissociated JSTa CI, the relative quantities of dissociated and un-
dissociated salt depending on the concentration of the solution.
Similarly solutions of hydrochloric acid contain the ions H and
CI and undissociated molecules of HC1.

It would seem at first that matters become more complicated
by thus considering the solutions just mentioned; while this is
true in some cases, namely when concentrated solutions are under
consideration, yet in dilute solutions where dissociation is nearly
complete things appear more simple. Thus in very dilute so-
lutions hydrochloric acid and sodium chloride are practically

completely dissociated, and the dissolved substances that these

+ —

solutions contain are consequently the ions H and CI in the

+ -

former and Ka and CI in the latter. The ions are to be re-
garded as distinct and separate substances subject, however, to
the law that the solution contains as many positive as negative
ions. The ions are furthermore not identical with ordinary hy-
drogen, chlorine and metallic sodium respectively, for they differ
from these in the amount of energy they contain. It is neces-
sary to supply these ions with additional energy in order to
change them from the ionic condition to the ordinary state.
This can be done, for example, by electrolyzing hydrochloric
acid or sodium chloride.

Two dilute solutions containing chemically equivalent quan-

KAHLENBERQ — ACTION OF SOLUTIONS ON TASTE. 7

tities of hydrochloric acid and sodium chloride are alike in that
they contain chlorine ions in the same concentration, while they
differ in that the former contains hydrogen ions and the latter
sodium ions. It has always been regarded as axiomatic that the
properties of a solution are determined by what the solution con-
tains. Hence the differences in the properties of the dilute so-
lutions of hydrochloric acid and common salt are simply to be
ascribed to the different effects of the H ions and the ]STa ions,
the CI ions being common to both solutions. Xow it happens
that a solution of hydrochloric acid still has a very pronounced
taste at a degree of dilution at which a common salt solution
containing a chemically equivalent quantity is perfectly taste-
less. It follows, therefore, that the taste of such a dilute solu-
tion of hydrochloric acid is simply due to the hydrogen ions it
contains. The dilute solution of hydrochloric acid gives one
the sensation of sour, and consequently hydrogen ions cause sour
taste. The latter statement will be more fullv established be-
low.

From what has been stated concerning the nature of aqueous
solutions, it follows that in the case of solutions of non-electro-
lytes we have simply to investigate the taste of the dissolved
molecules and to seek a relation between the chemical nature of
these and the sensations that thev cause; while in the case of
solutions of electrolytes, we shall have to consider the taste of
both the undissociated molecules and the ions present, trying to
discover if possible a connection between the gustatory sensa-
tions that these create and the other properties that they pos-
sess. It is clear that the study of the second class of solutions
may be much simplified by working with dilute solutions. By
so doing the taste of individual ions may even be determined as
indicated in the preceding paragraph.

The Seme of Taste.

The organs of the sense of taste are located in the epithelium
of the upper surface of the tongue and possibly also in the lin-
ing of other parts of the mouth cavity. The nerves of the

8 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

tongue run into papillae, of which the to-called circumvallate, on
the posterior part of the tongue's surface have an especially rich
nerve supply. On these are the terminal organs of taste con-
sisting of peculiar bodies, the so-called taste-bulbs or taste-buds,
discovered by Schwalbe and Loven in 1867. These taste-bulbs,
which are minute bodies, oval in shape, are lodged in the epi-
thelium covering the side of the papilla. Each consists of two
sets of cells. On the outside are a number of flat, fusiform, nu-
cleated cells known as supporting or protective cells; these are
bent like the staves of a barrel and arranged side by side so as
to form a bulb-shaped body, having an aperture at the apex
known as the gustatory pore. The inside of the taste-bulb con-
tains five to ten so-called taste-cells, which are pointed at the end
next to the gustatory pore and branched at the other end where
they are probably connected with nerve fibres. According to
Eanvier1 supporting cells are also found in the interior of the
taste-bulbs, the taste-cells being found interspersed between
these. Taste-bulbs occur also on other papillae of the tongue,
and it is possible that simpler structures consisting of fewer or
even single taste-cells exist where no taste-bulbs are located, for
it is known that taste does exist on parts of the tongue where no
taste-bulbs have been found. The tip, edges, and back of the
tongue are sensitive to taste, while the middle is devoid of
taste. The organs of taste are similar in construction to those
of smell.

The above is a brief statement of what is generally given con-
cerning the organs of taste in standard works2 on physiology,
histology, and physiological psychology. Ketzius,3 who has
made an, extensive study of the nerve endings of the various or-
gans of the special senses, states that he has been unable to find
nerve-fibres connecting the so-called taste-cells with the nerve
underneath, that the lower terminus of the taste-cells is in many

iTraitg Technique d'Histologie, p. 946.

2See for example Martin, The Human Body; Ranvier, Traits d Histologic;
Wundt, Grundztige der physiologischen Psychologie.
3Biologische Untersuchungen IV., p. 24.

KAHLENBERO — ACTION OF SOLUTIONS ON TASTE. 9

cases foot-shaped, and that it is highly improbable that they are
connected directly with underlying nerves. He finds that nerve-
fibres ramify between the cells throughout the entire interior
of the taste-bulbs. These nerve-fibres, which lie terms the in-
tralobular nerves, are a continuation of underlying nerve-;
they traverse the taste-bnib in a general vertical direction, lim-
ning out into free end- that are l< cated in many eases near the
gustatory pore, in other cases more remote from that opening.
Eetzins thinks the so-called taste-cells are true epithelial cells;
he regards them as "secondary sense cells,'' similar to the "hair
cells'' of the sense of hearing. Retzius then finds more analogy
between the organs of taste and hearing than between those of
be and smell. Speaking of the sense of taste, he says:1

"Es sind meiner Ansicht nach im Geschmacksorgan keine
wahren Sinnesnervenzellen vorhanden. Die Xervenzellen des
Geschmackser^ans hal en sich ebenfalls, wie im Tastorgan, aus
dem Epithel zuriiekgezogen und liegen in den Ganglion des
Geschmacksnerven. Das Geschmacksorgan steht also in rnor-
phologisch-phylogenetiseher Bezielnmg auf etwa demselben
Standpunkt wie das Tastorgan und gewissermassen das Gehor-
organ. Die weit gegen das Centralorgan zuriickgetretenen
Xervenzellen senden in das peripherische Organ ihren peripher-
ischen Fortsatz, welcher unter starker Verastelung mit frei aus-
laufenden Spitzen frei und interzellnliir im Epithel endigt; in
dem Epithel der Geschmackszwiebeln sind indessen eigenthiim-
liche Zellen vorhanden, welche ungefahr, wie die Haarzellen des
Gehororgans, als eine Art secundarer Sinneszellen anfgefasst
werden konnen." According to this view it is of course not
difficult to see why certain portions of the tongue are sensitive
to taste and yet possess no taste-bulbs.

It is generally accepted that sensations of taste are caused by
certain irritations of the nerve terminals, — whether we are to
regard the "taste-cells" or the "intracellular nerves" as repre-
senting these end-organs is perhaps still an open question, though
Eetzius appears to have excellent grounds for his opinion. Au-
thorities apparently agree that this irritation of the nerves is due

^oc. Cit., p. 53.

10 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

to chemical action upon them. Now in order to get into con-
tact with the end-organs a substance must be in solution. This,
however, is not of itself sufficient. To get into the taste-bulb,
the mouth of which is always covered with mucous, and to get
at the nerve, the dissolved substance must diffuse with a fair
•degree of readiness; and finally, when it has come into contact
with the nerve terminus, it must be capable of acting chemi-
cally on the protoplasm of the same, thus causing the irritation
that is interpreted as taste. Many substances are tasteless sim-
ply because they are insoluble; others, although sufficiently sol-
uble, do not diffuse readily enough to come into contact with
the nerve terminus; and still others, which though soluble and
sufficiently diffusible, are devoid of taste because they fail to
react chemically with the protoplasm of the nerve.

It is evident that for each substance there is a certain mini-
mum amount that must be present in order to cause sufficient
irritation at the nerve. This amount will naturally be relatively
less in the case of those substances that react more intenselv
with the protoplasm of the nerve terminus. Again, in the case
of those substances that because of very slow diffusion possess
but little taste, the solutions must be relatively much stronger
in order that sufficient substance may come into contact with
the nerve, for the speed of diffusion of a substance is propor-
tional to the difference in concentration that exists between the
two layers in contact. No doubt the mechanical action of rub-
bing the tongue against the palate as we do in tasting aids in
brino-ina- the substance to be tasted into contact with the taste-
organs. We should, other things being equal, expect a sub-
stance that diffuses readily to exert an effect on the end-organs
in less concentrated solution than a substance that diffuses more
slowly. The electrical conductivity of solutions of electro-
lytes is dependent upon the number of ions present and the
speed with which they move through the solution. From this
it is clear that the conductivity of electrolytes and their speed
of free diffusion are closely connected, and we should conse-

KAULENBERO — ACTION OF SOLUTIONS ON TASTE. 11

•quently expect to find a relation between the electrical conduc-
tivity of solutions and their effect on the end-organs of taste.

When volatile substances are introduced into the mouth, the
volatilized portions fill the mouth cavity and also the nasal pas-
sages; in the latter they frequently act on the organs of smell,
and we are very apt to confound the smell of such sul stances
with their taste. Indeed, it is well known that many volatile
substances, which we commonly regard as having a strung taste,
in reality have no taste at all, for when the nasal passages are
obstructed these substances are without taste. It is clear from
this that experiments on the sense of taste are best conducted
with substances that are non-volatile.

The sensations of taste are commonly classified as those of
■sweet, sour, salty, and bitter, to which Wundt1 adds alkaline and
metallic. There can be no doubt, however, that there are very
many kinds and shades of taste that are quite distinct and not
to be referred to sensations of touch, and that the above classi-
fication can claim at best to be only a very rough one. The
investigator of this subject is soon struck by the fact that we
have so few names to describe the various tastes. It is often
very difficult for the subject experimented upon to report in
words what taste the substance under consideration has, in spite
of the fact that a very definite impression is experienced.

The sense of taste is frequently regarded as rather vague, in-
definite and uncertain, probably in part because it is not more
definitely localized, and yet, experiments show that it is ex-
ceedingly sensitive toward many things, and the fact that it
may be cultivated to distinguish very small differences is be-
yond dispute.

The Method of Experimentation.

Fifteen persons served as subjects to be experimented upon.
Thirteen of these were between twenty and thirty years of age ;
of this number three were ladies. The other two, a lady and a

1Grundziige der physi«logischeu PyscTiologie I., p. 439.

12 EULLETIN OF THE UNIVERSITY OF WISCONSIN.

gentleman, were about sixty and sixty-three years old respec-
tively. All were in excellent health and were practically total
abstainers from the use of intoxicating liquors and tobacco.

The solutions, which were prepared with distilled water that
was practically tasteless, contained chemically equivalent quan-
tities, i. e., they were so-called normal solutions. I chose the
solutions of such strength that they would give me distinct im-
pressions of taste, not sufficiently strong, however, to produce
in any case lasting disagreeable or painful sensations. A por-
tion of each of these solutions was then diluted with water to
one-half its former strength; a portion of each of the solutions
thus obtained was again diluted with water to one-half its
strength, and so on until a solution was obtained, the taste of
which I could not distinguish from distilled water. About
200 cc of each dilution was prepared. The solutions were kept
in flasks thoroughly cleaned and steamed; they were labeled in
cipher known only to me. This wTas done because many of the-
persons tested were conversant with eheim'cal symbols, and it
was my purpose to have them entirely ignorant of the contents
of the solutions they were tasting, so that they would report the
sensations they received without being biased by thoughts as to
how the solution ought to taste. The chemicals used were of
the chemically pure kind of reliable makers. The distilled
water was ahvays used as a check.

The subject was first given an opportunity to thoroughly rinse
the mouth with distilled water so as to remove any excess of
mucous. Seated with his back toward the table on which were
the flasks containing the solutions, the subject took from a por-
celain spoon about four cubic centimeters of the solution to be
tasted. The individual held this in the mouth for a few mo-
ments, being permitted to move the tongue and lips at will so
as to spread the liquid over the entire cavity of the mouth, and
bring the liquid into more immediate contact with the mem-
branes by friction. The solution was then ejected, the report
given, and the mouth generally rinsed with a little distilled water

KAIILENBERG — ACTION OF SOLUTION'S ON TASTE. 13

before another solution was tasted. I had the person sit with
Ins back toward the table on which the flasks stood, for I found
it necessary that, in order to get from liini an unbiased report,
he should not know from which flask I was giving' him. In test-
ing as to the relative strength of the taste of several solutions, I
could thus give the same solution twice in succession or give
simply distilled water without the subject's knowledge. I found
that this procedure was quite necessary in many eases in order
to obtain reliable results. The distilled water and the solutions
were of the same temperature, about 23° C. As my purpose
was rather to compare the tastes of different solutions than to
find out in each case as accurately as possible the moat dilute
solution that could still be tasted, I did not deem it necessary to
raise the temperature of the liquids to that of the body.

Each person experimented upon was not detained more than
half an hour at a time, and the solutions were always given be-
ginning with the weaker and proceeding to the stronger. This
was very essential, for preliminary experiments indicated that
when a strong solution is first given the effect of it is apt to re-
main in the mouth and make other tests difficult for the time
being or perhaps even impossible. For the same reason, too,
all strong solutions that would be apt to leave a prolonged taste
in the mouth were either entirely avoided, or given the subject
as the last solution to be tested at that sitting. The solutions
used were in all cases perfectly odorless unless otherwise stated.

The Taste of Solutions of Electrolytes.

The taste of solutions of electrolytes received attention, first,
because these solutions have in many cases very pronounced
tastes that render work with them relatively easy; furthermore,
when I first began the experiments, it was simply my purpose
to investigate the taste of the ions; as the work progressed it
took a somewhat wider scope, nevertheless most of the experi-
ments were conducted with solutions of electrolytes.

Sour Taste. As pointed out above the sour taste of acids is

14 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

due to the hydrogen ions present.1 In order to firmly establish
this experimentally a 355 hydrochloric acid solution was prepared ;
this I found to have a very decided acid taste. From this solu-
tion 335, j&j and 555 solutions were prepared as before described.
On testing the fifteen individuals mentioned, it was found that
four of them could detect a difference between the ^ solution
and the distilled water, while all of them distinctly tasted the $&
solution. The ^ solution was reported not as sour, but as
slightly astringent ; the ~ was reported as astringent by the men
but by the ladies uniformly as astringent and slightly sour.2 As
at these dilutions the dissociation of the hydrochloric acid is
practically complete, and as it requires a much stronger solution
of Na CI than ^ to cause taste, as will be shown below, it
is clear that the sour taste is simply due to the effect of the hy-
drogen ions. I have no doubt that with cultivation of the taste
for hydrogen ions, and previous elevation of the temperature
of the solutions to that of the body, even more dilute solu-
tions than 555 could be detected by the sense of taste. Indeed,
the experiments of Richards3 confirm this. He shows clearly
that fairly accurate titrations of hydrochloric acid can be made
using the taste of the solutions to indicate the end of the- reac-
tion.

The 355 solution of hydrochloric acid was uniformly re-
ported as sour, as was of course also the Ufa. Solutions of sul-
furic, hydrobromic, and nitric acids equivalent to those of hy-
drochloric were also prepared, and the subjects were tested with
these. The results were the same as with the corresponding so-
lutions of hydrochloric acid. The Jk solutions were re-
ported as astringent by those that could distinguish them from
distilled water, ^ were reported as astringent by the men

1After the presentation of this paper to the Wisconsin Academy and before it
could be published, there appeared an interesting article by T. W. Richards on
"The Relation of the Taste of Acids to Their Degree of Dissociation," Amer.
Chem. Jour., Feb. 1898. He also expresses the idea that sour taste is caused by
hydrogen ions.

20n the whole, I found but little difference in the delicacy of the taste of the
different persons tested; I had anticipated much greater individual differences
than I actually found.

3Loc. Cit.

KAHLENBERG — ACTION OF SOLUTIONS ON TASTE. 15

and as astringent and slightly sour by the women, while all
found the & and ^ solutions distinctly sour. No difference
either qualitative or quantitative could be distinguished by these
individuals between the solutions of these various acids of equiv-
alent strengths. The electrical conductivity1 of solutions of
these acids shows that in their TO solutions the compounds are
practically completely dissociated, the number of undissociated
molecules present at this concentration is then practically nil.
It will be shown below that the sodium salts of these acids in ^
solutions, or even much greater concentrations, are tasteless.

In testing solutions of acetic acid it was found that m could be
tasted as astringent while ra was reported as sour, though much
les6 so than TO solution of the other acids mentioned. The elec-
trical conductivity of solutions of acetic acid shows that in ^,
and TO solutions the degrees of dissociation are about 6 per cent,
and four per cent, respectively. One would then expect acetic
acid solutions to be less sour than equivalent solutions of the
strong mineral acids; at the same time, it is apparent that if hy-
drogen ions can be tasted as astringent in ^ solutions, a ^ solu-
tion of acetic acid, which is dissociated only about 6 per cent,
and hence with respect to hydrogen ions is ^ normal, ought
to be tasteless. To be ^ with respect to its content in hydro-
gen ions, a fa acetic acid solution ought to be dissociated 25
per cent. It is clear then that the ^ solution of acetic acid, be-
ing dissociated only about 6 per cent, has a sour taste about four
times as strong as it ought to have, assuming that the taste is-
due simply to the hydrogen ions momentarily present. Rich-
ards2 obtained a similar result; he fotmd that the acetic acid was
about one-third as strong as an equivalent solution of hydro-
chloric acid, though the acetic acid was only dissociated to the
extent of one-fourteenth. Eichards gives no explanation of this
phenomenon, and at the present time I also have none to offer.
The further investigation of this point together with that of the

JSee Ostwald, Allgemeine Chemie 2, p. 722 et seq., also Landolt u. Bornstein's=
physikalisch-chemische Tabellen.
2Loc. Cit.

lfc» BULLETIN OF THE UNIVERSITY OP WISCONSIN.

interesting question of the taste of acid sodium salts of polybasic
acids is contemplated.

The foregoing results and those of Richards show conclusively
that hydrogen ions have a sour taste ; furthermore, it is clear that
in very dilute solutions they produce simply an astringent sen-
sation. The question arises, Is sour taste always due to the
presence of hydrogen ions? I am inclined to answer this ques-
tion in the affirmative, for I know of no substance that has a
sour taste which on going into solution in water does not yield
hydrogen ions.

With regard to the astringent effects, it seems that in many
if not in all cases these can he ascribed to the presence of
hydrogen ions in about ^ solution. I was deeply impressed
with the fact that many of the subjects tested said that the
jJe solutions of the mineral acids tasted like alum. It has
been shown1 that alum solutions contain hvdrogen ions in small
quantities due to the so-called hydrolytic dissociation of the
aluminum sulfate, i. e., to a reaction of this salt with water
forming a small amount of sulfuric acid from which in turn
by electrolytic dissociation hydrogen ions form. In presence
of the sulfate of the alkali metal an acid salt would no doubt
form from which, according to previous investigations,2 hydro-
gen ions split off rather difficultly. The acid reaction of alum
solutions toward indicators is of course further proof of the pres-
ence of hydrogen ions. The astringent taste of solutions of fer-
ric salts and their acid reaction toward indicators are well
known; these solutions like those of aluminum salts have long
been used in medicine because of their astringent properties,
which I am inclined to ascribe to the hydrogen ions present due
to hydrolytic dissociation. This statement is of course not to be
construed as meaning that the other ions and the undissociated
molecules present in these solutions do not exert an effect, for

1See Long's work on the inversion of sugar by salts, Jour. Amer. Chem. Soc.
18, Feb. and Aug., 1896.

2See Trevor, Zeitschr. f. physik. Chem. 10, p. 321; Tower, ibid. 18, p. 17 u. 21,
p. 90; Smith, ibid. 25, p. 144.

KAHLENBERG — ACTION OP SOLUTIONS ON TASTE. 17

no doubt they do especially in strong solutions, and to these
effects the differences of the individual solutions are due.

It is well known that solutions of most of the salts of the heavy
metals have acid reactions and that they have an astringent ef-
fect upon the membranes of the mouth, besides creating in some
cases the so-called metallic taste. The solutions of all of these
salts contain hydrogen ions whose presence is caused by hydro-
lytic dissociation as in the case of the salts of iron and alumi-
num. To these hydrogen ions the astringent effect of the solu-
tions is very likely to be ascribed in many cases. Salts of
stronger acids with the alkalies are not decomposed hydrolyti-
cally and do not possess astringent properties. Long1 used the
method of sugar inversion in investigating the hydrolytic decom-
position of salt solutions. He employed a polariscope in his
work and consequently could test only colorless solutions. The
freezing- and boiling-point methods, however, can be used quite
as well as the polariscope in this work; although by means of
them the observations are perhaps not quite as accurately and
readily made. They possess the advantage, however, that they
can be used with colored solutions. Experiments along this line
have for some time been in progress in this laboratory and the
results will soon be ready for publication.

As to the nature of the chemical action of the hydrogen ions
on the nerve nothing definite is known, indeed the same must
be said of the action of any ingredient on the nerves of taste.
It is significant, however, that hydrogen ions can be detected
by the sense of taste in very dilute solutions, the limit being
in the neighborhood of ^, or one gram of hydrogen ions in
800,000 grams of water. The speed of migration of the hydrogen
ion exceeds that of any other ion; it is about one and three-
fourths times that of the next fastest ion, the hydroxyl ion. In-
timatelv connected with this is the fact that solutions of strong
acids diffuse more rapidly than those of their salts. By virtue
of their great mobility, it is clear that hydrogen ions can easily

UjOC. Cit.

18 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

get at the end organs of taste. It is well known that hydrogen
ions in many cases accelerate chemical action, i. e., they have
a so-called catalytic effect. Whether it will be found that they
accelerate the action that goes on in the nerves or unite with
their protoplasm, can not be stated now; it does seem suggestive,
however, that the ion which has the least relative mass and by
far the greatest mobility can be tasted in more dilute solutions
than other substances and causes that peculiar sharp sensation.

Alkaline Taste. — Dilute solutions of caustic alkalies have the
characteristic alkaline taste. The effect upon the tongue is very
different from that produced by hydrogen ions. In aqueous
solutions the caustic alkalies are dissociated into hydroxyl ions
and the ions of the metal or basic radical; thus in the case of
NaOH the ions are Na and OH, in the case of KOH, K and
OH, etc. Solutions of the hydroxides of sodium, potassium and
lithium of the strengths 553, afo m anc^ m were prepared, and
their taste was investigated as in the investigation of the acids.
It was found that ^ NaOH could not be distinguished from dis-
tilled water; the ^ solution could be tasted very faintly; —
the taste was difficult to describe, some calling it a rather stale
taste. The ^ solution was reported as alkaline by all, at the
same time some also received a slight sensation of bitter from the
same. The solution of KOH and LiOH yielded essentially the
same results. The persons tested apparently were not able to dis-
tinguish any difference either qualitative or quantitative between
solutions of equivalent strength of these three alkalies. The al-
kalinity of a jj-5 solution of NaOH is plainly recognized by the
sense of taste. In this solution the dissociation of the XaOH is
practically complete. As a solution of XaCl of equivalent
strength is tasteless, as will appear below, it follows that the alka-
line taste of the XaOH solution is to be ascribed to the effect of
the OH ions. Hydroxyl ions then have the so-called alkaline
taste. In stronger solutions caustic alkalies are known to pro-
duce nausea. It is probable that this is due to their large con-
tent of OH ions, the caustic alkalies being even in fairly concen-
trated solutions in a relatively highly dissociated state.

KAHLENBERG — ACTION OF SOLUTIONS ON TASTE. 19

It is well known that solutions of salts of strong bases with
Yerv weak acids have an alkaline reaction toward indicators. This
is due to the fact that, these salts are to a certain extent hydro-
ly tit-ally decomposed by the water into free acid and caustic al-
kali, the latter yielding OH ions by electrolytic dissociation. As
examples of salts whose solutions possess alkaline reactions and
tastes because of the OH ions due to hydrolytic dissociation
may be mentioned the carbonates, silicates, and borates of the
alkalies, and the soaps. The fact that the latter In strong so-
lutions produce vomiting- is well known; probably this effect is
due to the OH ions present in the solution-.

The taste that a dilute solution containing OH ions causes
is difficult to describe. Some of the persons tested said it was
a soft, smooth sensation quite unlike that produced by other sub-
stances. It would seem somewhat peculiar perhaps that the
taste of hydroxy 1 ions, being not sharp like sour or salty tastes,
should manifest itself in solutions containing only one gram ion
(i. e., 17 grams of OH) in 400 liters. It must be remembered
in this connection that hvdroxvl ions, like hydrogen ions, are
generally speaking very reactive. What the nature of the ac-
tion of the OH ions on the protoplasm of the nerve is, is not
known. The mobility of OH ions is very great (being second
only to that of II ions as already pointed out), consequently we
should expect them to find little difficulty in reaching the nerve
endings.

Water itself is slightly dissociated into hydrogen, and hydroxy!
ions. The degree of this dissociation is, however, exceedingly
small. Very pure water has been prepared by Kohlrausch, the
electrical conductivity of which showed that there were no more
than 18 grams of dissociated water present in eleven million li-
ters. It is clear that this is far beyond the limit at which H
and OH ions can be detected by the sense of taste. It is not
very difficult to obtain distilled water of a specific conductivity
of 2xl0~6 and such water is devoid of taste. If we inquire as
to the reason for this, we should agree that the undissociated
molecule of water is tasteless because it does not react chemically

20 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

■with the protoplasm of the nerve; the other alternative, that it
does not reach the nerve because of too slow diffusion is here
excluded.

Salty Taste. — The taste of common salt is generally given as
the type of salty taste. It was found that of the persons tested
only three could distinguish a slightly salty taste in -^ solution
of sodium chloride, while all recognized -§■ as a trifle salty. It
requires then a much stronger solution to produce the salty taste
than either the sour or the alkaline. In ~ solution Na CI is dis-
sociated to the extent of about 91 per cent, and in ■£ to about
88 per cent. As equivalent solutions of sodium acetate are
not salty, possessing hardly any taste, it is clear that the salty
taste of the common salt solutions is due to the chlorine ions-
The fact that borax solutions of equivalent sodium content are-
not salty and that many of the individuals tested found difficulty
and others could not distinguish between ^ solutions of KC1,
LiCl, and !NaCl, argues in favor of this view. The taste of the
ions of the alkali metals will be discussed later.

Sodium bromide solutions of the strength ■§■ were found to
be distinctly salty by all ; a few seemed to taste the -fa solution,
but very faintly. This salt is dissociated to about the same
extent as the corresponding solutions of sodium chloride. The-
salty taste of the solutions of Xa Br is due to the Br ion.
The sense of taste is apparently able to detect this ion in solu-
tions nearly as dilute as the chlorine ion. I found that several
persons seemed to detect a qualitative difference between •£
!N"aCl and JsoBt solutions by the sense of taste, others again
reported no perceptible difference. Those that did find a dif-
ference said that the chloride solution was a little sharper than
that of the bromide.

Sodium iodide solutions could be tasted in •£ solutions and
more clearly in £. In neither of these cases was the taste,
salty. It takes about a ^- solution to cause the salty taste to
appear. The same was observed in case of solutions of potas-
sium iodide, only here the taste of ■£ solutions was more marked
and rather bitter. The behavior of these solutions will again be

*©*

KAIILENBERG — ACTION OF SOLUTIONS ON TASTE. 21

considered below in connection with the taste of cathions. It is
evident from the result* obtained that iodine ions do not have
as salty a taste as do bromine and chlorine ions. The salty teste
of the chlorine, bromine, and iodine ions decreases as the atomic
weight increases. The mobility of these ions as determined
from the conductivity of the respective sodium salts is nearly the
same.

In working with sodium nitrate, I found that all the indi-
viduals could taste a jf^ solution, though very faintly. They
found it impossible to describe the taste. The £ solution
was a trifle salty to eight, but they said it was quite a different
taste from that of sodium chloride. Of the others, three could
not describe the taste, four said it was a smooth taste, and one per-
son said it was more like that of borax than common salt to him.
In £ solutions sodium nitrate is dissociated over eighty per
cent, and in ^ about 90 per cent. It follows that neither
the Xa nor the X03 ions have a very pronounced effect on
the sense of taste. The slightly salty taste of the £ solution
is probably due to the X03 ion, for the sodium ion does not
produce such an effect, as is evident from the taste of solu-
tions of sodium acetate. The speed of migration of the sodium
ion is about -f of that of the hydrogen ion, and the speed of
the X03 ion is about -f that of the hydrogen ion.

Sodium sulfate was tasted in ■§■ solution, though not as
salty. It was found difficult to describe the taste. Even in
i^- solution this substance did not produce a salty taste. In -g%
solution a salty taste described by some as slightly bitter was
recognized, though all agreed that the "salty taste'' was different
from that produced by common salt. In ■£■ solutions Xa2 S04
is dissociated about 75 per cent, and in ^- about 62 per cent.
The result shows that the S04 ion does not have a very pro-
nounced taste. The mobility of the ion 4" S04 is about that
of the halogen ions mentioned above.

Solutions of sodium acetate of the strengths -£, ^, and -fa
were distinctly tasted but in no case reported as salty. The
taste was variously described as smooth, sweetish, faintly alka-

22 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

line, etc. Even when this salt is taken into the mouth in
very concentrated solution the taste is not salty. Indeed,
the taste is not pronounced and it is most difficult to describe
it in words. From the taste of sodium acetate solutions it
follows then, that neither Xa ions, CH2COO ions, nor undis-
sociated molecules of sodium acetate possess a strong taste.
The taste of sodium ions is but slight, they seem to produce a
smooth sensation that can not be detected in very dilute solu-
tions. Tins together with the fact that sodium salts are most
strongly dissociated admirably adapts the latter for investigating
the taste of anions of various kinds. Since sodium ions mi-
grate only 4 as fast as hydrogen ions their rate of diffusion is
relatively slow and this may in part account for the fact that
they do not affect the sense of taste more. There seems but
little room for doubt that in the presence of an ion of pro-
nounced taste, the taste of the sodium ion is completely 'masked.

The Taste of Cathions. — The tastes of hydrogen and sodium
ions have already been discussed in connection with the taste of
the anions. To find the taste of a cathion we shall choose a
solution of a salt the anion of wdiich has little or no taste at a
dilution at which the salt is fairly nearly dissociated and at which
the cathion can still be tasted.

The taste of potassium ions is rather bitter and disagreeable.
Solutions of the nitrate, sulfate, and acetate of potassium that
can be plainly tasted produce, especially on the back of the
tongue, a bitter and rather disagreeable taste. The correspond-
ing sodium salts do not produce this effect, and as potassium
salts even in fairly strong solution are highly dissociated, this
effect is to be ascribed to the action of the potasium ions. Thus
the individuals tested could taste KX03 solutions that were
-£; the report was that the taste of the solution was smooth,
alkaline (?) . In ^ solution the same taste together with a bit-
ter sensation was reported, while ■£ solution was found to be de-
cidedly disagreeable. In -^- and y£- solutions KN03 is disso-
ciated about 77 per cent, and 87 per cent, respectively; as the
corresponding sodium salts at these concentrations do not pro-

KAHLENBERG — ACTION OP SOLUTIONS ON TASTE. 23

duce this bitter taste, which is characteristic of all potassium salts,
it is clearly to be ascribed to the potassium ions. The mobility
of potassium ions is about one and one-half that of sodium ions so
that their diffusion is more rapid. The taste of potassium ions
being fairly pronounced, it is not as readily masked as that of so-
dium ions. Thus it is possible to distinguish solutions of KC1
from NaCl and KI from Xal; the iodine ion not having as
strong a salty taste as the chlorine ion, the difference in taste be-
tween the potassium and sodium ions comes out fairly distinctly
in dilute solutions of the last named salts. Sulfate of potassium
solutions have the characteristic bitter, disagreeable taste of the
potassium ions; these solutions lack the sharp taste of the N03
ions, which we have in strong solutions of KN03 and other ni-
trates when these are applied to the tip of the tongue. Solu-
tions of KC103 do not have the salty taste of the chlorine ions.
The bitter taste of the potassium ion is somewhat masked by
the effect of the C103 ion, the latter acts especially on the tip
and edges of the tongue creating its own characteristic sharp
taste. Solutions of XaBr03 were incidentally tested in this
connection; they have but a slight taste which is not salty. The
Br03 ion has a taste similar to that of the C103 ion, which would
naturally be expected. The tip of the tongue is quite suscep-
tible to irritation by various salts, many of them giving that
peculiar sharp or burning sensation, which is different from the
taste of hydrogen ions; thus, KI, Nal, NaCl, NH4C1, etc.,
besides the nitrates when applied in strong solutions on the very
tip of the tongue cause a burning sensation, which they do not
produce on other parts of the organ.

Lithium ions appear to have but little taste. A •£ solu-
tions of Li N"03 was very difficult to detect by taste ; £% gave
a rather alkaline smooth impression, and -fa a sharp taste like
a solution of jSTaK03 of equivalent concentration. This
sharp taste is probably due to the action of the nitrate on
the tip of the tongue and is to be ascribed to the action of the
N03 ion. The mobility of the lithium ion is only a little over
one half that of the potassium ion, hence its diffusion is slower,

24 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

which would in part account for its less pronounced taste. The
taste of magnesium ions is probably bitter as appears from the
taste of magnesium sulfate solutions. It takds about ^ to ,*■-
solutions of this salt to produce a distinctly recognizable bit-
ter taste. In the latter concentration the salt is dissociated
only about 40 per cent, so that it is an open question as to
whether the undissociated molecules of MgS04 or the Mg
ions cause the bitter taste. Magnesium ions very likely have a
bitter taste as other solutions in which they occur have this taste;
probably the undissociated molecules also have a similar effect.
In solutions of MgCl2 we have both the bitter taste of the Mg
ions and the salty effect of the CI ions. The combined effect
is such as to make the taste of the solutions of this salt most
disagreeable. A solution of MgCl2 that was £ was recognized
as salty but not as bitter, while ^ and -fa solutions produced
both the salty and bitter effects, which is what we should expect
according to the dissociation theory and the results obtained in
case of MgS04 and NaCl as given above. Id ■& solution the
degree of dissociation of MgCl2 is about 70 per cent. The
mobility of the ion f Mg is about the same as that of the
lithium ion.

The taste of Ca(N03)2 is a trifle sharp in ^ solutions
and distinctly bitter in-£. It is a different bitter from that
of the solutions of magnesium salts. The bitter taste of the
Ca (M)3)2 solutions is probably due to the Ca ions. The mo-
bility of the Ca ions is about the same as that of the Mg ions.

Solutions of ammonium sulfate give scarcely any salty taste;
their taste is rather to be described as bitter. This taste is caused
by the NH4 ions and the undissociated molecules (NH4)2 S04.
The probability is that NH4 ions have a bitter effect, since
K"H4K"03 solutions, besides creating a sharp, burning taste on
the tip and edges of the tongue, also have a bitter taste.

To get substances whose solutions have a characteristic "me-
tallic" taste, silver nitrate and mercuric chloride were selected.
It was found that even in ^ solution silver nitrate could still
be tasted, while in ^ its taste was very pronounced. From

KAHLENBERG — ACTION OF SOLUTIONS ON TASTE. 25

the limit of taste of sodium nitrate solutions as given above
approximately, it follows that at the dilutions just mentioned
the taste of silver nitrate solutions is simply that of the silver
ions. Silver ions have a peculiar puckering effect on the mem-
branes of the mouth which, if the impression has not been too
weak, will remain for some time. The taste is frequently spoken
of as "metallic." At first it would seem that silver ions can be
tasted in more dilute solutions than hvdrogen ions: this is true
when we compare chemically equivalent quantities, but since
the atomic weight of silver is about 108, a ^ solution of silver
nitrate contains 1 gram of silver ions in 46300cc, while an ^5-
solution of hydrochloric acid contains 1 gram of hydrogen ions
in S00000 cc.

Solutions of mercuric chloride can be very faintly tasted
when j^,, plainly when jfo. the "metallic" taste being some-
what similar to that produced by silver ions. Mercuric chloride is
not highly dissociated in solutions that are not very dilute. The
concentrations just mentioned are such, however, that in them
.the salt is lare-elv electrolvticallv dissociated. As CI ions can
not be tasted in ^ solutions, it is clear that we get here the taste
of the mercury ions.1

The Relations of Overton's Work to the Taste of Solutions.

Ernst Overton in an interesting article, "Liber die osmotischen
Eigenschaften der Zelle in ihrer Bedeutung fur die Toxikologie
und Pharmakologie mit besonderer Berlicksichtigung der Am-
moniake und Alkaloide" (Zeitschr. f. physik. Chem. 22, p. 189,
1897), gives a list of organic groups arranged according to the
•degree of retardation that they exert in preventing the sub-
stance in which they occur from passing through vegetable and
animal membranes. The list beginning with the group that re-
tards most is as follows:

1. The amido-acid group.

2. The carboxyl group.

1 Compare the work of H. Dreser, Zur Pharmakologie des Queeksilbers, Ref.
Zeitschr. f. physik. Chem. 13, 37, 1894.

26 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

3. The acid-amido group.

4. The alcoholic hydroxyl group.

5. The aldehyde group.

When several of these groups occur in one and the same com-
pound, the retarding action increases with the number of groups-
in a rapid geometrical progression; for example, while sub-
stances that contain but one alcoholic hydroxyl group readily
pass through membranes, those that contain two or more such,
groups find increasing difficulty in doing so as the number of
groups grows larger.

In order to affect the nerves of taste substances must be read-
ily diffusible, as was previously pointed out; it follows, there-
fore, from the above table of Overton, that compounds contain-
ing the amido-acid or acid-amido group should have little or no-
taste. Glycocoll (CH2.NH2.COOH), which is soluble in about
four parts of cold water, has a weak sweetish taste. In order
to taste the substance, concentrated solutions or even a crys-
tal directly must be taken into the mouth. Acetanilid, C6H5
NH(C2H30), though readily soluble has almost no taste
even in saturated solutions. Asparagin, C2H3.]SriI2.CONIl2..
COOH, which dissolves easily in water, is almost perfectly
tasteless even in its strongest solutions. Acetamid, CH3.CO.
NH2, also readily soluble, does possess a characteristic taste,,
which, however, is not very strong. It is difficult to ascertain
the true nature of this taste as it is not easy to eliminate the
mouse odor that the solutions of this substance have. Overton
emphasizes that the acid-amido group does not exert nearly as
great a retarding influence as does ihe amido-acid group, hence
the behavior of acetamid is perhaps such as would be expected.
Urea, CO.(NH2)2, very soluble in water, has a slightly bitter
taste reminding one of that of the magnesium ion. Biuret, NH
(CO.iSni2)2, readily soluble, is practically tasteless; its most
concentrated solutions are veiy faintly bitter.

It is difficult to study the effect of the carboxyl group be-
cause acids dissociate yielding hydrogen ions the taste of which
is so strong that it masks that of other molecules present in the

KAHLENUERO — ACTION OF SOLUTIONS ON TASTE. 27

solution. The fact that solutions of sodium acetate, of sodium
oxalate and sodium tartrate have no pronounced taste is evi-
dence that the anions of these acids have but a slight effect, if
any, on the end organs of taste.

The alcohols having but one hydroxyl-group, possess taste and
also a very strong odor. As it is extremely difficult to exclude
the smell of these substances while tasting them, nothing was
done with them experimentally.

Great interest attaches to the polyatomic alcohols. Of th<
ethylene-glycol having two hydroxyl groups and glycerine with
three hydroxyl groups have a sweet taste that can readily be
detected in strong solutions. Erythrite with four hydroxyl
groups and mannite with six are practically tasteless; only in
very strong solutions were these substances found to be sweet.
The taste of a sample of dulcite was pronounced to be nil even
in the strongest solutions, while isodulcite and sorbite were found
to be slightly sweet.

Turning now to the sugars, arabinose, laevulose, d-glucose
and galactose were reported to be sweet, as were also maltose
(malt sugar) and saccharose (cane sugar), while lactose (milk
sugar) and xylose were found to have little or no taste. The
The aldehyde groups occurring in sugars, seem to render them
more capable of permeating membranes, and probably they also
modify the compounds so that in their action on the nerve they
increase the sweetish taste, which on the whole is characteristic
of the alcohols containing several hydroxyl groups. The inten-
sity of the tastes of the polyatomic alcohols and the sugars is
then in general such as one would expect viewing the matter in
the light of Overton's work.

The Taste of the Alkaloid*.

Overton found that coniine, nicotine, sparteine, etc., very
readily pass through protoplasm; of the alkaloids that contain
oxygen, codeine, thebaine, cocaine, atropine, strychnine and
brucine diffuse very rapidly, whereas morphine diffuses more
slowly and ecgonine very slowly. The burning taste and the

28 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

characteristic odor of coniine and nicotine are well known, as is
also the very bitter taste of sparteine. With the exception of
thebaine, the other alkaloids mentioned also have pronounced
bitter testes. The taste of ecgonine, which, though very solu-
ble, passes through membranes slowly, has been described as
bitter-sweet. Thebaine seems to behave in an exceptional man-
ner; it is very soluble, veiy poisonous, passes through mem-
branes with great readiness, and yet is tasteless according to
some authorities.1 I have not been able to verify this since a
sample of the substance was not available. With the apparent
exception of thebaine, however, it is important to note that the
alkaloids which diffuse readilv through membranes and which
are known to exercise a strong physiological effect on the nerves
are also able to get at the nerve endings of the sense of taste, re-
acting upon the same with vigor, producing disagreeable burn-
ing or bitter tastes.

Colloidal Solutions.

As typical colloidal solutions may be mentioned solutions of
dialyzed silicic acid, ferric hydroxide, aluminum hydroxide, also
solutions of albumen, gelatine, gums, etc. These solutions are
practically non-conductors of electricity, i. e., they contain few
or no ions; they have boiling and freezing points that differ but
very little from those of water. The rate of diffusion of colloids
is very slow, and in general they are very inert in their chem-
ical behavior. Besides those already mentioned, other charac-
teristics of colloidal substances are that they have no definite
solubility and that their solutions gelatinize when treated with
certain reagents. These colloidal solutions are devoid of taste.
This is very likely due to the fact that the molecular weight of
colloidal substances is very large and their diffusion so very
slow that they can not get at the nerve endings; though, be-
cause of their inert character, it is quite reasonable to sup-
pose that, even if they were able to come into immediate contact

1 See for example Watt's Dictionary of Chemistry 4, p. 68L

KAHLENBERG — ACTION OF SOLUTIONS ON TASTE. 29

with the protoplasm of the nerve, they would probably not re-
act with it sufficiently to produce sensations of taste.

Retrospect.

One may briefly summarize the salient points contained in
the foregoing as follows: —

1. In order that a substance may affect the sense of taste,
it must be soluble in water; it must be readily diffusible; and
it must be capable of reacting chemically with the protoplasm
of the terminals of the nerves of taste.

2. The modern theories of solutions lead to the conclusion
that the taste of a solution that conducts electricity ought in
general to be that of the ions and the undissociated molecules
that the solution contains; furthermore, the taste of a solution
in which ionization is practically complete should be simply that
of the ions. This is supported by the results of the investiga-
tion of the taste of solutions of electrolytes above given.

3. Sour taste is caused by hydrogen ions. The sense of taste
is able to detect hydrogen ions even in -^ solutions. In more
dilute solutions than •£$, hydrogen ions may cause simply an
astringent sensation. The sour taste of acetic acid solutions has
been found to be more intense than it ought to be according to
the degree of dissociation of the substance. !No explanation of
this phenomenon has thus far been attempted.

4. Hydroxyl ions produce an alkaline taste, which can be
perceived even in -$%■ solutions. In strong solutions their
taste is exceedingly disagreeable. Pure water, being very
slightly dissociated, is tasteless probably because its undissociat-
ed molecules do not act on the protoplasm cf the nerve.

5. Chlorine ions have a salty taste. The taste of common
salt solutions is mainly that of chlorine ions. Chlorine ions
can still be faintly tasted in -^- solutions. Bromine ions also
have a salty taste, which, however, is slightly different in qual-
ity from that of chlorine ions. The sense of taste appears to
be able to detect chlorine ions at a slightly greater dilution than
bromine ions. The ions C103 and Br03 have a somewhat similar

30 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

taste; which, however, is not sharp and salty like that of chlor-
ine and bromine ions. Iodine ions have a salty taste but it is
different in quality and less intense than that of either chlorine
or bromine ions. It takes about a ■■• solution of iodine ions to
produce a distinctly salty taste.

6. The taste of K03 ions is slight, probably a trifle salty;
only in strong solutions do they produce a sharp burning sensa-
tion on the tip and edges of the tongue. The ions S04 and
CH3 COO have but very little taste; the effect of the latter
seems to be a trifle sweet.

7. The taste of sodium ions is slight. It is difficult to de-
scribe, being a smooth effect on the tongue somewhat similar
perhaps to that produced by a very dilute solution of hydroxyl
ions. Potassium ions have a more pronounced taste than sodium
ions. It is a peculiar, bitter, rather disagreeable taste that can
be much more readily detected than can that of sodium ions.
Lithium ions have no pronounced taste, their effect is some-
what like that of sodium ions, though less in degree. Magne-
sium ions are bitter. It takes about a £ solution to cause a dis-
tinctly bitter taste. Calcium ions are bitter, but the taste is
different in quality from that of magnesium ions. Ammonium
ions also have a bitter taste. The taste of silver ions is "me-
tallic"; they cause a peculiar puckering sensation on the mem-
branes of the mouth cavity. Even a ^ solution of silver
ions can still be tasted. Mercury ions can be faintly detected
by the sense of taste in ^ solution. Their taste is "metallic"
and their effect on the membranes of the mouth cavity reminds
one of that of silver ions.

8. The intensity of the salty taste of the halogen ions de-
creases as the atomic weight increases. The investigation of
the cathions also indicates that a relation exists between their
taste and their atomic weights in the sense of the periodic law.
When the taste of the ions is compared with their mobility as
expressed by their speed of migration under the influence of
the electric current, a number of instances are found that would
point to the conclusion that the greater the mobility the more

KAIILENBERO — ACTION OF SOLUTIONS ON TASTE. 31

intense is the taste; but there are many exceptions that show
that the intensity of the taste produced by the ions is not simply
determined by the readiness with which they can get at the
nerve endings, but also by the reactions they undergo with the
protoplasm, which of course are determined by the chemical
character of the ion.

9. The intensity of the taste of solutions of substances con-
taining amido-acid, acid-amido, alcoholic hydroxyl, and aldehyde
groups was investigated, and it was found that the results, ob-
tained are in general such as one would expect viewing the mat-
ter simply in the light of Overton's determinations of the rel-
ative readiness with which these substances permeate plant and
animal membranes.

10. It was pointed out that in general the alkaloids have a
pronounced bitter taste, that according to Overton nearly all
permeate protoplasm readily and that furthermore, they are
known to exert a strong physiological action on the nerves.

11. Colloidal solutions are tasteless because the substances
they contain diffuse very slowly and are chemically very inert.

Laboratory for Physical Chemistry,

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 36

Science Series, Vol. 2, No. 2, Pp. 33-198. Pls. 1-2

ASPECTS OF MENTAL ECONOMY

AN ESSAY IN SOME PHASES OF THE DYNAMICS OF MIND, WITH

PARTICULAR OBSERVATIONS UPON STUDENT LIFE

IN THE UNIVERSITY OF WISCONSIN

BY

M. V. O'SHEA,

Professor of the Science and Art of Education.

Published bi-monthly by authority of law with the approvul of the JCegenU

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
April, 1900

PRICE 75 CENTS

^uUetitt of the ^JLnivtv&itig of Qfii&coxt&ixx.

(flomtnittee of publication

CHARLES KENDALL ADAMS, President of the University

WILLIAM HERBERT HOBBS, Editor-in-Chief

EDITORS

Nelson Oliver Whitney, Engineering

Frederick Jackson Turner, Economics, Political Science, and History

Charles Forster Smith, Philology and Literature

William Herbert Hobbs, Science

BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 36

Sciencc Series, Vol. 2, No. 2, Pp. 33-198

ASPECTS OF MENTAL ECONOMY

AN ESSAY IN SOME PHASES OF THE DYNAMICS OF MIND, WITH

PARTICULAR OBSERVATIONS UPON STUDENT LIFE

IN THE UNIVERSITY OF WISCONSIN

BY

M. V. O'SHEA,

Professor of the Science and Art of Education, University of Wisconsin

LIBRARY
NEW YORK
BOTANICAL

GARDEN.

Published bi-monthly by authority of law with the approval of the Regent*

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
April, 1900

CONTENTS.

INTRODUCTION.

CHAPTER I.

THE RELATION OF MIND AND BODY — AN ENEROEIC CONCEPTION.

§ 1. An Historical View 44

2. The View of Experimental Science 46

3. Neural Fatigue: Its Nature and Motor Effects 50

4. Neural Fatigue: Intellectual Effects 55

5. Neural Fatigue: Emotional Effects 60

CHAPTER II.

CEREBRAL HYGIENE AND ECONOMY IN STUDENT LIFE.

§1. The Student's Obligations to the State 64

2. The Study of Psychical Processes,— Dangers, Advantages. . . 65

3. The Educator's Concern with Cerebral Hygiene 67

4. Studies at the University of Wisconsin: Purpose and Methods 68

CHAPTER III.

RELATIVE VALUE OF FOODS IN THE PRODUCTION OF NERVOUS ENERGY.

§ 1. The Philosophy of Nutrition 73

2. Statistical Summary of Studies on Foods 78

3. Composition of the Food Stuffs Found in the Tables 82

4. Composition and Value of Food Materials not Found in the

Dietary Lists °6

5. The Nutrient Value of Students' Dietaries,— Estimates and

Comments 90

6. Specimen Dietaries Fulfilling the Requirements of Adequate

Nutrition 101

CHAPTER IV.

RELATIVE VALUE OF FOODS IN THE PRODUCTION OF NERVOUS

energy (continued).

§ 1. Condiments as Force-producers 107

2. The Influence of Tea, Coffee, and Cocoa upon the Production

and Expenditure of Force in the Organism 108

3. The Influence of Alcohol in Wine, Beer and Other Beverages

in the Production and Expenditure of Force 115

4. The Influence of Tobacco upon the Production and Expendi-

ture of Force in the Organism 123

36 CONTENTS.

CHAPTER V.

THE PREPARATION OF FOOD — HOURS FOR MEALS.

§ 1. The Philosophy of Cookery 126

2. Modes of Cooking,— Local Practices with Criticisms 128

3. Hours for Meals 131

CHAPTER VI.

INDIVIDUAL PECULIARITIES IN DIGESTIVE CAPACITIES.

§ 1. The Theory of Individual Differences 139

2. Concrete Examples 1*0

CHAPTER VII.

EXPENSE OF DIETARIES.

§ 1. Taste vs. Expense in the Choice of Poods 145

2. The Cost of a Dietary of Different Foods 146

3. Local Expenses, with Practical Suggestions 149

CHAPTER VIII.

FRESH AIR, EXERCISE, AND REST IN THE PRODUCTION AND EXPENDITURE OF

CEREBRAL ENERGY.

§ 1. Function of Oxygen in the Organism 153

2. Exercise

3. Sleep 163

CHAPTER IX.

THE CONSERVATION OF ENERGY.

§ 1. Wasteful Muscular Tensions 170

2. The Daily Program 187

3. " Tell me what company you keep, and I will tell you what

you are " 196

ASPECTS OF MENTAL ECONOMY.

INTRODUCTORY.

In this essay I have ventured to discuss from a particular
point of view the question, How can a student make the most
of himself ? In one or another of its aspects this matter is
considered alike by religion, by psychology, by ethics, by educa-
tion, by hygiene, and by other philosophies and sciences. Each
regarding a special phase of man's being seeks to advise him
concerning his conduct so that he may attain the highest pos-
sibilities of his nature. Thus, religion counsels him respecting
the deportment which will prepare him for habitation in an-
other world ; ethics aims to so determine his demeanor that he
may dwell in the spirit of justice with his fellowmen; educa-
tion delineates the processes by which he may secure the full-
est development of intellect and character. The phase of this
large subject which is discussed herein is indeed a^ narrow but
yet, I believe, an exceedingly consequential one. Taking a
doctrine accepted by modern science, that, looked at in a certain
light, a human being is seen to be a machine fashioned to do
a given amount of work, depending upon the quantity of en-
ergy which may be utilized for this purpose, I have sought
to examine the ways in which this energy can be most read-
ily generated and wisely conserved so that it may be employed
in profitable production of either a mental or physical sort.

The view-point I have taken is what might perhaps be called
an energeic1 one. If this should sound too materialistic to
some readers they will certainly not be aggrieved when they.

1I coin this word to express precisely a certain relationship of mind and
body which is discussed at length in the course of the essay.

38 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

consider that there 'has been no attempt to examine the entire
nature of an individual. JSTo one could imagine that the only
problem involved in a person's success in life relates to the
generating and conserving of nervous force. This is surely im-
portant enough, but yet more important things follow. When
one is in possession of his forces then the question arises, what
shall he do with them ? In what direction shall he expend
them ? What is really worth while ? The answers to these que-
ries must be sought for in the principles of religion, education,
and allied departments of knowledge concerning human life.

I am well aware that I have discussed in an inconclusive
manner some topics connected with my subject. Indeed, cer-
tain problems have been simply opened up for more detailed con-
sideration later rather than settled in any satisfactory way. This
is made necessary at the present time by the unbroken character
of the field. So far as I know there has as yet been little serious
effort to discuss deportment from an energeic point of view,
and in a comprehensive, systematic form. All that has been
done is of an isolated, fragmentary character, and most of the
available data concern more or less simple processes which are
likely to have their properties much modified when combined
into the complex thing we call conduct. These data are scat-
tered through a number of sciences ; and what I have attempted
to do is to gather up the most relevant of them and interpret
them in the light of one another, and by the aid of observa-
tion and experience, keeping constantly in mind local practices
and conditions. I regret that it has not been possible to in-
vestigate in a more thorough manner several of the matters
treated ; but if those who feel the lack of certainty will be
stimulated to undertake detailed and exact studies for them-
selves, some good will have been done. I am convinced, though,
(and this is a source of consolation), that for practical purposes
it is often quite as efficient to direct an individual's attention to
the consideration of a certain line of conduct as to presume
.to give him explicit directions respecting his actions.

OSHEA — ASPECTS OF MENTAL ECONOMY. 39

It may occur to some that this subject is as a whole an ex-
tremely large and complicated one to be treated according to
scientific methods. They may feel conduct consists of such a
bewildering complexity of factors operating together that it is
for the present impossible to handle it with that precision which
is the sine qua noil of scientific procedure. Science in our day is
minutely analytic, dissective ; it seeks to single out from habitual
associates particular factors or phenomena and investigate their
properties. It attaches relatively little value to investigation
which cannot control the conditions accompanying a phenome-
non to be studied; for when we take a thing in the large, when
we cannot separate it from its milieu, so to speak, it is not easy
to see what elements are really most active in determining its
nature. But now so far as psychological experiment is con-
cerned, it is utterly impossible by any known methods of in-
vestigation to cut off elementary psychical processes wholly
from each other. Experimental psychology may attempt to
investigate an isolated sensation, for instance ; but such a thing
is a pure abstraction. In the intricacy of the psychic organism
one element never can be entrapped apart from others with
which it has become inseparably associated through experiences
no less in phylogenesis than in ontogenesis. The most that can
be done is to limit the run, as it were, to hedge it in on every
side; to have, that is to say, as few factors as may be enter-
ing into a problem. The results of the most accurate experi-
ments then in the mental sciences are only relatively more ex-
act than those of observation or experience. It may be permis-
sible to point out in passing that in our time there is some
danger of experimental psychology conveying the impression
that it is more precise than it ever can be. In a considerable
part of present-day scientific writings one is led to think that
the most primary phenomena have been examined with mathe-
matical accuracy, when as a matter of fact there must have
been left out of account accompanying conditions which deter-
mined to a greater or less extent the behavior of the thing
studied.

40 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

While in general the analytic method of experimental science
is to be highly commended, still in some situations it is proba-
ble that more satisfactory results can be attained by studying a
thing in the large than in its elements, — macroscopically rather
than microscopically. The French school of psychologists, fol-
lowing the lead of Binet and Henri, maintain that more of genu-
ine worth for science is gained by examining an individual
human mind in its totality, so to speak, than in its elements;
while the German school, represented notably by Kraeplin, take
an opposite view, — that reliable results can be secured only by
a study of the most elementary processes in different minds.
The one studies the living, complex entity, the other dissects
and examines relatively simple factors. The movement in our
own country seems just now to be headed in the direction of
the French rather than of the German school. At all events,
it should be apparent that we can apprehend, and that truth-
fully, characteristics in an organism when various forces work
together that we would miss if we concentrated our attention
solely upon each separate factor. These latter are not differ-
entiated enough, it may be, to claim our attention; it is only
when a vast number of them co-operate, when their properties
are pooled, so to speak, and we have a personality, that we dis-
cern the significance of their total influence.

So in the study of conduct there are certain advantages in
viewing a person as a whole, as an entity whose distinctive attri-
butes are not apparent in each primary factor of mind or body.
And this may be done with something like scientific precision.
To illustrate, I may describe with accuracy the conduct of a
drunken man without investigating in detail the simple physical
and mental processes which totalized beget the state of inebria-
tion. If I see clearly and tell truthfully my story may be relied
upon. So one may set forth the effects of certain modes of
living upon the energies of the organism without studying the
most elementary phenomena involved in the total process. A
fact observed, whether it relate to exceedingly complex or mark-
edly simple objects, is in any event a fact and as such is worthy

O'SHEA — ASPECTS OF MENTAL ECONOMY. 41

of our credence. Thus history may be considered to treat of
the utmost conceivable complexity of subjects which, in their
extremest analyzable form, are considered by neurology_ and
analytic psychology. But the principles of history are not on
this account to be regarded as less trustworthy than those of
neurology. Microscopic study, just because of its minuteness,
is not more reliable and trustworthy than macroscopic study;
you can describe as well (and it may be better) the conduct of a
horse as that of an amoeba. That it may be valid though, of
-course your description must be verifiable alike by experience
and by experimental research ad libitum; but so long as it stands
the test it must be accorded all the honors and privileges of sci-
entific knowledge.

I know it is a hazardous thing to express an opinion upon
matters respecting which every one is an authority. And if
there is one matter more than another which needs no study
to comprehend, it is that which has to do with the regulation
of our daily lives. Here, common-sense, elsewhere so little
trusted, is esteemed a wise guide. It is one of the simplest
principles of psychology that we all tend to make our thoughts
•and actions standards by which to estimate their own value.
It is difficult for me to believe that the factors which have
produced me are beyond improvement ; what I do must be right.
Every one entertains Phantoms of the Cave when such familiar
things are under inspection; and this it is which makes it so
hard to convince people that they should ever modify their con-
duct. But it ought to require no argument to prove that the
self-standard in deportment is no standard at all. Because I
have been living in a certain manner and have survived is no
evidence that I could not have lived better by adopting a differ-
ent regime.

A woman was recently discussing the subject of food, and
contended that modern scientific investigation was valueless if
not detrimental in promoting happiness in life. She had
brought up a family in violation of all the rules of hygiene re-

42 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

spectmg diet, and she instanced her six grown sons and daugh-
ters to prove that hale and hearty children could be reared
on "unhygienic victuals." As a matter of fact, however, these
"stalwart" men and women are taking medicine half the time ;
and not one of them has yet accomplished anything of conse-
quence in the world. But this woman, beholding them through
a mother's eye, is convinced that perfection has been attained in
their construction ; while a disinterested neighbor sees the mat-
ter in a quite different light. It is a far cry from the grave
to the most energetic and efficient living; and because one is
alive is no evidence that he could not be more alive. It is
not assured beyond question that one out of jail is a good citi-
zen ; nor is it at all conclusive that because one is "getting on"
in the world he could not swing along with greater momen-
tum by the aid of a knowledge of some of the principles of
mental mechanics. It would indeed be a remarkable circum-
stance if by accident alone we should have hit upon the very
best ways of ordering the minutse of our daily lives, when it
is seen how great advances, what discoveries of beneficial meth-
ods are made by careful study in other fields. If science can
do so much for us in simple matters how much more ought
it to help us in the most complex and intricate of all affairs, —
the adjustment in harmonious relations of a human being to
his environments. But the very complexity overwhelms the
common mind, stops up the avenues of thought, and it falls
back on the universal platitude of ignorance, "Oh ! there's noth-
ing in it anyway."

On the other hand, one too conscious of his demeanor in re-
spect of the petty details of life is in so far limited in his
efficiency. A mind turning in always upon itself or upon bod-
ily processes throws the machinery of life out of gear. Speak-
ing in general terms that mind is the best instrument that is
concerned with objects outside of self, when the organism ad-
justs itself to the attainment of these ends; then things work
together in harmony. This is the ideal. But yet through
early ignorance or through the necessity of adaptation to waste-

O'SHEA — ASPECTS OF MENTAL ECONOMY.

43

ful conditions in our environments we may fall into practices
that lessen the efficiency of our forces. By a little thought these
prodigal habits may be supplanted by better ones, when the
mind may again be free. Xow, the requirements of mental hy-
giene do not demand one to be constantly dwelling upon his ac-
tions ; they simply ask him to exchange certain not too deep seat-
ed habits by others, and to make these latter automatic as soon as
possible. In the matter of producing energy, those who have
charge of our dietaries and our living apartments are the ones
who should become conscious of our needs ; and if landlords and
club managers were only experts in their business and could
supply us according to our necessities, we should then be relieved
from attending to such matters for ourselves, and greatly to
our advantage. But as the situation exists in our midst it seems
needful that those who suffer should search out their own rem-
edy; and it is to be hoped that this will not breed too great
consciousness respecting in a way trivial matters, but only that
it may serve to bring about, certain simple modifications in diet
and living which will soon fall into the regions of habitual and
subconscious action.

44 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

CHAPTER I.

THE RELATION" OF MIND AND BODY. AN ENERGEIC CONCEPTION.

§1. An Historical View. — From the earliest times men have
debated over the connection between the physical and the mental
in the human organism. This has been the problem of chief-
est concern, at various stages in the development of thought,
alike for mythology, for religion, for philosophy, ' and in our
own era for experimental science. The conception of mind
most characteristic of primitive reflection in the individual as
in the race regards it as a tenant of the body ruling over and
directing its activities, and being influenced itself in some meas-
ure, great or small, by bodily conditions, and what may be
called physical or outward demeanor. This notion does not
postulate any organic relationship between, much less identity
of, mind and body. There is but a sort of tangential relation,
so to speak ; and the spirit can if it will free itself wholly from
the control of the material structure in which it is momentarily
entombed. It is onlv when the volitional element in one's be-

*J

ing is lethargic that he yields to the promptings or suggestions
of his physical self, which, most unhappily, are natively of an
evil mien. Holding this view men believed during long epochs
in human history that they ought to scourge and maltreat the
body that they might thus purify and strengthen the spirit ; for
if the animal be not held under subjection by such discipline
it will endanger the supremacy of the man: a doctrine quite
contrasted to the theories of these latter days, when it is pro-
claimed on every hand that the more respect we pay the body,
and the kindlier and more faithfully we attend its needs the
greater will be the reward in spiritual exaltation and freedom.
Correspondent with the development of physical science in
its earlier years, however, there gradually arose another and a
vitally different theory, — that in an ultimate analysis mind

O'SIIEA — ASPECTS OF MENTAL ECONOMY. 45

can be reduced to material terms. This conception becomes
easily established in the evolution alike of the racial and of
the individual mind, since the phenomena occurring in mental
disease, and particularly in injury to or degeneracy of the cen-
tral nervous mechanism lend themselves readily to such inter-
pretation. People remark that if the brain suffer damage from
any cause some mental defect or deficiency usually ensues ; and
when for whatever reason the cerebrum becomes inactive, there
is no evidence of any supra-cerebral activity remaining. So
far, in short, as we can observe mental activities ab extra, they
appear to be directly dependent upon or rather aspects of neural
processes. This second view then makes mind a phase or phe-
nomenon of matter, — one of a group of physical forces origi-
nating in the degradation of highly organized chemical sub-
stances.

There is yet a third hypothesis1 which regards the mind
and the body, so far as it passes opinion upon the essential
nature of each, as distinct entities, but in some inexplicable man-
ner bound to each other in such a way that the activities of the
one necessitate correlated activities in the other. The advocates
of this theory pin their faith to what may be styled a dynamic,
or better, energeic relation between mind and body. They do
not deem it needful to explain how this relation is possible, al-
though theories looking in this direction are not wanting. A
common one espoused by James and others considers the nerve
cell as the instrument, and the sole instrument, by which mind
may be displayed in a material world; and if the neural ele-
ments which constitute the via media for this physical exhibi-
tion of a non-physical order of being be deficient in any way,
then simply mind cannot manifest itself at all, or only in a
manner we call defective or abnormal.

1 Typical presentations of this the now prevalent view may be found, among
many other references, in Lotze, Microcosmus ; Darwin, Descent of Man; Ro-
manes, Mental Evolution in Man; Wallace, Darwinism; Fiske, Destiny of Man
in the Light of His Origin; Drummond, Ascent of Man; Wundt, Human and
'Animal Psychology, pp. 5-7 and 440-445 ; James, The Will to Believe, chap, on
Reflex Action and Theism.

46

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

§2. The View of Experimental Science. — Whatever be the
true philosophy of the inter-relations of mind and body,
modern experimental science is quite assured in the view that
they are inseparably connected in their activities. The doc-
trine that "every psychosis is accompanied by a neurosis" has
been adequately demonstrated for many people by the results
of experimentation in physiological and psychological labora-
tories,1 as well as in the laboratory of Nature, pure and sim-
ple, wherein she reveals to us through pathological disturb-
ances the normal order of things ; although, of course, complete
and final evidence upon this subject is for the present at least
quite beyond the skill of science to obtain. But it seems rea-
sonably certain for one thing (the only one that concerns us
here), that all mental activity, and physical as well, involves

Fig. 1.

Fig. 2.

Figs. 1 and 2.— Representations of typical nerve cells (Donaldson, Growth of the
Brain, pp. 143 and 145) designed especially to show the elements concerned in
the reception of stimuli, d; in the generation and storage of potential nervous
force, N; and finally in the transmission of kinetic nerve energy, n.

the expenditure of energy generated in the nuclei of neural
cells. The architecture of the cell, in the absence of more
suggestive experimental data, would of itself lead one to this

1For the opinions of investigators as Mosso, Lombard, Maggiora, Kraeplin
and others, see the Pedagogical Seminary, Vol. II, No. 1, pp. 13-17 ; Scripture,
The New Psychology, chap. XVI : and Educational Review, Vol. XV, p. 246 et
seq.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 47

inference. The plan of construction, as doubtless every one
knows, is simple, — a central body or nucleus serving the pur-
pose of husbanding resources, as it were; and, radiating out
from this are fibers or pathways some of which are designed
to convey impressions in the form of sense stimuli to the nucleus
of the cell, while others bind into a social union cells in dif-
ferent regions of the cerebral community. (See Figs. 1 and 2.)

The bodies comprising the nucleus of the cell are believed
to be of a highly complex and unstable chemical composition,1
in consequence of which they are easily broken down, the
energy represented in their union thus being liberated and dis-
sipated ultimately in incitement to motor activity, or possibly in
thought. Neurology assumes, what was stated above, that all
mental and physical action requires for its initiation and main-
tenance the liberation of a measure of this mysterious force held
in potentia in the nuclei of nerve cells.

People do not commonly think, in part because they do not
reflect upon the matter, that mental activity occurs at the ex-
pense of the contents of cerebral cells. Even critical intro-
spection reveals thought as a spiritual activity dissociated from
or at least not dependent dynamically upon physical processes.
It is not easy for me to conceive that my ideas are linked to
material agencies, and remain dormant except when these are
.active; no matter for present needs which is cause and which
-effect. And yet if one will note the physical accompaniments
■of his thinking he will not lack for opportunities to see that
arduous mental work requires a comparatively great supply of
blood headwards, which is shown in distention of blood ves-
sels and in a sense of pressure or strain in the cephalic regions.
Every student must have observed also, if he at times becomes
attentive to the bodily concomitants of his mental processes
(which, let it be said in passing, is a tendency not generally
to be nurtured, but rather to be combated) that continued study
increases the temperature of the head.

1Ladd. Physiological Psychology, pp. 13 and 14, gives the following formulae
for some of the substances : protagon, Ci16 H24i O3^ P. ; cholesterin, C»« H44
O + Ha O.

48 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

These phenomena are easily observable in psychological ex-
periments, wherein it is possible to show that wThen a subject
exerts his mind in the effort to solve a difficult problem, for
example, the volume of blood in the cerebral locality increases.
It was the physiologist, Angelo Mosso,1 I believe, who first di-
rected the attention of scientists to this in his investigations
with the plethysmography And he was able to demonstrate the
same phenomenon also in another experiment. A subject is
placed upon a delicately constructed balance which remains
horizontal while he is in a condition of mental repose; but
when he is summoned to severe intellectual effort, or when
any lively emotion is aroused, the balance tips in the direc-
tion of the head, showing that the blood is surging brain-
ward and so of course away from the limbs. The increase in
temperature during mental activity has been studied by Lom-
bard, Schiff, and others by means of the thermo-electric needle
plunged into the brains of dogs and other animals.2 When
in this latter case any sense was stimulated, as smell, the nee-
dle if placed in the olfactory region of the brain would show
that heat was being liberated.

The significance of these well-known but yet little appreciated
phenomena becomes apparent when they are interpreted in
view of the accepted explanations of similar phenomena occur-
ring during muscular exertion. It is a simple physiological
fact that the blood supply in a muscle is greater during activity
than while at rest, caused by the necessity of removing and
repairing the increased waste produced by the degradation of

1 Reference is made to this phenomenon in Mosso's Fear, p. 68. The subject
is treated in detail with respect to methods of investigation, and results in Die
Ermiiding, pp. 195 et seq. There is a very good r6sum§ of recent investigation
relating to the effect upon circulation of intellectual and emotional activity, to-
gether with the presentation of results of original researches, in the Psycholog-
ical Review for January, 1899, by Angell and Thompson, — The Relation between
Certain Organic Processes and Consciousness.

A. Binet and V. Henri in La Fatigue Intellectuelle, pp. 81 et seq., recognize
that intellectual activity produces dilation of the cerebrum, but they do not
attach so great importance to this phenomenon as many do. Their discussion
does not bear directly upon the problem involved here, however.

2 See Pedagogical Seminary, loc. cit.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 49

living tissue while engaged in work. Now, it may be readily
inferred that the phenomenon of augmented cerebral circula-
tion during vigorous intellectual or emotional activity is identi-
cal in principle with the muscular phenomenon just noted. Cor-
roborative testimony in proof of this energeic dependence of
mind upon cerebral cells is afforded by the observations of
physicians1 who maintain that certain toxic products of nerv-
ous action increase parri passu with intensified intellectual or
emotional activity. Mosso's demonstration of a distinction be-
tween muscular and neural fatigue2 requires for explanation
the assumption that nervous as well as physical action results
in the accumulation of a sort of debris in the system, which
is undoubtedly nothing but worn-out or degraded nerve sub-
stance, and which may heap up to such an extent as to dis-
turb the normal functions of the neural mechanism. Especially
does it tend to throw out of gear the inhibitory apparatus,
paralyzing the fatigue sense, as some one has said, and thus
removing the natural checks to excessive physical or mental
exertion, when the organism continues in activity beyond the
safety limit.

The experiments of Hodge3 apparently show quite conclu-
sively, in the case of animals at any rate, that the activity of the
cell depletes the nucleus of its contents,, revealed in a gradual
shrinking while stimulation continues, as shown in Figs. 3 and 4.
,This phenomenon, which he was able to detect while experi-
menting with a living cell under stimulation, was observed also
in the examination of animals at night after a day's activities,
pnd in the morning when they had passed a long period in
rest. In the first instance the nuclei of the cells were shrunken,
while in the morning they presented a repleted appearance,

1For instance, by Cowles : Neurasthenia and Its Mental Symptoms; Beard:
Neurasthenia, edited by Rockwell ; Mills: Mental Overwork and Premature Dis-
ease Among Public Men, Smithsonian Institute, No. IX of Toner Lectures.

2 See for further discussion, p. 52.

3 Some Effects of Electrically Stimulating Ganglion Cells, American Journal
of Psychology, vol. II, p. 376 et seq. ; and, Process of Recovery from Fatigue Oc-
casioned by the Electrical Stimulation of Cells of the Spinal Ganglia, Am. Jour,
of Psy., vol. Ill, p. 530 et seq.

4

50

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

showing that the demands of waking life had resulted in par-
tial exhaustion of their stock of force-producing materials.

Fig. 3.

Fig. 4.

Fig. 3. — Two sections, A and B. from the first thoracic spinal ganglion of a cat.
B is from the ganglion which had been electrically stimulated through Ita
nerve for five hours, A from the corresponding resting ganglion. The
shrinkage of the structures connected with the stimulated cells is the most
marked general change. N, nucleus ; N. S., nucleus of the capsule ; V., va-
cuole x 500 diameters. (Hodge.)

yIG. 4. — Showing the change observed in the nucleus of the living sympathetic
nerve cell of the frog, as the result of electrical stimulation. At the beginning
of the experiment the nucleus is seen to be replete with what we may call
potential nerve energy : but after thirty minutes of stimulation it appears
somewhat shrunken, and the shrinking increases as the experiment proceeds.
At the end of six hours and forty-nine minutes the shrinking of the nucleus
Is very marked. (Donaldson,1 after Hodge.)

§3. Neural Fatigue: Its Nature and Motor Effects. — Mod-
ern science then conceives of the brain as a generator and reser-
voir, so to speak, of energy which is essential to the activity
of body or mind. A proposition growing out of this is self-
evident, — that when one's resources are expended in one direc-

1 Growth of the Brain, p. 320.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 51

tion they cannot at the same time be employed in another. In
amplification of this axiom attention may be called to what
every one has doubtless observed, that when one is engaged in
hard muscular labor, he is less keen and vigorous in his men-
tal processes; and when he is under great emotional excite-
ment he cannot accomplish so much intellectually. Again,
when the vitality of the system is dissipated in repairing the
ravages of disease, the individual is unable to command so
great force in the accomplishment of either physical or mental
tasks. This conception, which is endorsed by experience and
substantiated by physiological and psychological science, is a
most important one as it relates to the ordering of the daily
life of any person and especially that of a student. To but
indicate its bearings here, it may be pointed out that the vigor,
efficiency, and spontaneity of either physical or mental activi-
ties in the business, social, and educational world depend in
some degree upon the amount of nervous capital one has on
deposit in the central nervous mechanism. Abundant research
has proven, it seems, that cerebral depletion (and depletion
is, of course, a relative term in respect of the readiness with
which it ensues in different people) reduces the force of mus-
cular effort, renders attention less concentrated, resulting in
a gradual obscuration of mental vision, and estranges the emo-
tional nature, begetting a general condition of disphoria and
apprehensiveness, and removing restraints upon anti-social im-
pulses, as jealousy, anger, irritability, and similar traits of a
low order of development.

Mosso,1 Maggiora,2 Lombard,3 Bryan,4 Kraeplin,5 and others
have shown that in a condition of fatigue muscular activity
is lessened in force and reduced in rapidity; and this

1Ueber die Gesetze der Ermiidung, Archiv. fiir Phys. (DuBois Reymond.)
Hefts, I and II, 1890.

JUeber die Gesetze der Erniiidung. Untersuchungen an Muskeln des Menschen.
Archiv. fiir Anat. und Phys. (DuBois Reymond.) Physiologie, 1890, pp. 89-243.

3 Some of the Influences which Affect the Power of Voluntary Muscular Con-
tractions. Journal of Physiolgy, vol. XIII, pp. 1 and 58.

4The Development of Voluntary Motor Ability, Am. Jour, of Psych., 5, p. 123
-et seq.

6 A Measure of Mental Capacity. Popular Science Monthly, vol. 49, p. 756.

52

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

is no doubt to be accounted for in largest part by
the fact that what we are wont to call muscular fatigue
is in reality quite largely central or nervous fatigue. When
a subject under experiment continues to exert force through
the arm, say, until his muscles become perfectly inert, they
may then be stimulated with electricity to act with initial vigor,,
indicating that they are still in workable condition; and after
a period of stimulation in this way, the will of the subject
remaining quiescent, he can again voluntarily energize the arm,,
as is shown in the following figures.

llfobL. _il

lUfifl

UdlMiUillMiL _

i

Fig. 5. — Showing ergographic tracings (1) in voluntary effort, (2) in electrical
stimulation of nerve, (3) in electrical stimulation of muscle. (Scripture1
after Mosso.) The relative heights of the tracings represent the relative
amounts of energy expended in the several forms of stimulation. It can
be seen that in voluntary effort the subject gradually loses power of exer-
tion and is soon unable to exert any force whatever ; but if at this point a
nerve leading to the muscle which has been acting (in this instance the
middle finger was exercised) be excited by electricity, the tracings show that
the muscle is as vigorous as ever. The fatigue in the voluntary effort
must then have been central or mental. Again, if when action ceases from
nerve excitation the muscle be directly stimulated there is once more a re-
turn of power, indicating that the muscle itself fatigues much more slowly
than the nerve mechanisms concerned in voluntary effort.

Fig. 6 shows the rhythm in the fatigue of voluntary effort (Scripture2). At F
is shown a period when the subject could exert no force whatever, although
he earnestly endeavored to. Soon after this space of paralysis, however,,
there is a return of ability again for a brief time. These tracings were ob-
tained upon the dynamometer by means of the hand grip.

iThe New Psychology, p. 231.
2 Ibid., p. 229.

O SHEA — ASPECTS OF MENTAL ECONOMY.

53

ULIUlillUulll

ALTERNATINQ

Voluntary. ElectkiC

Fig

7. This figure (Scripture1 after Lombard) shows the independence of
muscular and voluntary fatigue. Lombard first stimulated a muscle by vo-
lition, then by electricity, and continued the stimulations alternately as indi-
cated in the figure. At first the voluntary tracings show greater force ex-
erted, but this is gradually lost until the effect for volition and from elec-
trical stimulation are about equal. Then there is a recovery of volitional
power, which subsides again, only to return in a sort of rhythmical period,
which is very apparent from the tracings.

■■life

L 1

L

llul

ill

I

I.

i' pi it'

' H'i' li'l;
U'JL'llllJlJUllIiUUbl

OS

F<3

H

FiQ. 8 shows the effect of mental work upon the power of contraction of the
finger at various hours of the day. (Mosso, loc. cit.) The first curve, from
A to B, indicates the amount of work which could be done at 9 a. m. From
2 p. m. until 5 :30 p. m. the subject was under great mental strain while con-
ducting an examination in the university. After the examination, at 5 :45
p. m., the curve from C to D was gained. The first contraction of the fin-
ger shows as much power as in the morning, but the energv is soon ex-
hausted. Then after supper, at about 7 :30 p. m., the increase from E to P
was taken, and it indicates a slight increase in the endurance of energy.
Finally at 9 p. m. the fourth curve was made, showing a slow recovery of
original power.

This principle in its general bearings has been recognized
practically in every-day experience, particularly in the train-
ing of athletes; for it is well known that their physical vigor
and endurance depend in great degree upon their mental con-
dition (See Fig. 8), or as the saying goes, upon their nerve.
They are expected during the season of training to secure an
abundance of food and sleep, and to abstain from dissipation
so as to keep the nervous system in thorough repair ; and it
would doubtless not be an overstatement to say that athletic
contests are won by virtue of the power and control conferred

1Ibid., p. 232. The figure is a copy made by Scripture from an original rec-
ord furnished him by Lombard.

54 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

upon the athlete whose life is ordered in conformity to the re-
quirements of neural hygiene rather than by superiority in mus-
cular brawn per se.

The visible manifestation of cerebral fatigue most in evi-
dence in the affairs of daily life is the lack of power to secure
delicate and sustained co-ordination of bodily activities. Tasks-
demanding exact control and fine adjustment of muscles, as in
delicate workmanship for instance, are exceedingly difficult when
one is nervously exhausted. The explanation is doubtless found
in the fact that different sections in the brain are charged with
the control of certain definite motor processes, one section
having general oversight of the large, coarse, fundamental move-
ments, a, second one governing the secondary and more com-
plex movements, while still other sections control the peripheral,
the most finely adjusted movements, — those for instance, in-
volved in the co-ordinations of the fingers and the articulatory
apparatus in speech.1 This highest level, to employ Hughlings-
Jackson's term,2 may be regarded as the co-ordinating mechan-
ism, par excellence, of the nervous system. Now, in cerebral
fatigue, as in intoxication or mental disease, this level seems
to suffer first because it is the most unstable ; and nervous deple-
tion will then manifest itself at the outset in inability to deli-
cately correlate these most intricate movements.

This is at the root of much of what in the common affairs
of life we call "carelessness," one of those terms which con-
veniently covers up a lack of critical analysis, grouping, and
interpretation of phenomena. An individual who in a condi-
tion of fatigue is performing a task requiring exact adjustments
of any kind, as fine writing for instance, will be unable to
co-ordinate his actions so perfectly as when nervously refreshed,
and this will result in blundering, coarse work. Warner5

1For a fine treatment of this subject see the Pedagogical Seminary, Vol. VI,
No. 1, pp. 5-65. The matter is brought down to date in this article. See also
Mercier, Sanity and Insanity, Chaps. I and II.

2 See Anderson, in Hack Tuke's Dictionary of Psychological Medicine, Vol. I»
pp. 440 et seq. for a discussion of Hughlings-Jackson's theory, which seems now
to be accepted by practically all physicians.

3 The Study of Children, pp. 52 et seq.

0'8IIEA — ASPECTS OF MENTAL ECONOMY. 55

ascribes this want of precision, which is simply inco-ordination
carried to a point where it becomes noticeable, to the spasmodic
functioning of nerve cells in a condition of fatigue. The inhib-
itory apparatus does its work less efficiently; but inhibition is
absolutely essential for fine adaptations in motor activity.
The Hughlings-Jackson theory would account for the phenom-
enon under consideration by declaring that the co-ordinating
areas in the brain are unable to act with accustomed author-
ity, and movements result which are not so fully under the
direction of the will.1 This view is strongly supported by
data gained from the investigations of ^losso,2 Lombard,3 and
others. But whatever the neurological explanation may be,
it is enough for practical purposes to recognize that the ex-
haustion of nerve centers results in a general lessened power of
delicate co-ordination of motor activities.

Again, as was intimated above, fatigue has a retarding in-
fluence upon the rapidity of physical action.4 This phenom-
enon is apparent in the case of athletes who are contesting
in activities demanding ready response to stimulus. When
fatigued they do not start so readily in running, or gather them-
selves so quickly or act with such continued force in defense
or offense where promptness in execution and sustained power
are the decisive factors. When it is realized how much of the
success of life depends upon quickness and certainty of action
in the countless situations requiring these qualities in which
one is placed every day no matter what his calling may be, the
importance of preserving to the fullest extent possible the hy-
giene, or perhaps better the vigor of the brain can be appreciated.

§4. Neural Fatigue: Intellectual Effects. — While nerve de-
pletion has indeed a very unhappy influence upon motor abili-
ties, still the harm done here is probably not so great as that

iCf. Scripture, The New Psychology, pp. 228 et seq.
2Loc. cit. ,

8Loc. cit.

*See Scripture, op. cit., pp. 128-129, and 243 et seq.; also Bryan, on The De-
velopment of Voluntary Motor Ability, Am. Jour, of Psy., 1892, p. 123.

56 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

sustained by the intellectual faculties. The latter consequence
of brain fatigue is of chiefest concern to the student alike in his
immediate daily duties and in his future vocation, which will
for the most part require of him keen perception, accurate, ready
memory, and, above all, careful and judicious reasoning. From
what has gone before it must be apparent now that fatigue im-
pairs those cerebral conditions which are essential to normal
intellectual activity; and the most prominent effect of this in
the mental life is to render attention less concentrated and en-
during than when one is in good neural form, so to speak.
Any person who has endeavored to apply himself to arduous
undertakings when his resources have been too heavily taxed
knows that it is with great difficulty he can hold his mind to
the thing in hand, and he is likely not to succeed at all in the
attempt. As James has said,1 one grasps at everything in or-
der to find relief from the object before him. At this time
ideas crowd into the focus of consciousness which in seasons of
mental vigor can be inhibited ; and the upshot of it is that dis-
traction ensues; the mind grows inaccurate and lethargic, and
arrives finally at a state which, lacking a better term, we may
name stupidity.

From the point of view of neurology the dispersion of atten-
tion in cerebral fatigue is simply explained. It has already
been said that the co-ordinating, the regulative functions of the
brain are disturbed in neural depletion, and there attends this
condition a sort of independence of the various nerve centers
resulting in lessened subordination of irrelevant motor activities.
The individual does things that in better times he would be able
to inhibit. Now, the neural capacities essential for right phys-
ical co-ordination are, it seems, requisite as .well for mental co-
ordination ; and what renders one impossible will interfere also
with the proper action of the other Concentrated attention re-
quires the convergence of the mental powers upon one point,
with of course restraint of disturbing impulses; but as the in-
hibitory processes are less vigorous and constant in fatigue,

lPsychology, Briefer Course, p. 225.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 57

mental application is as a consequence less perfect. Ill-adjust-
ment, disperseness, whether found in physical or mental action,
are due to the same causative agencies. Mental degeneracy be-
gets physical as well as psychical inco-ordination; imbecility is
characterized no less by lack of control and balance physically
than mentally. It seems as if we are able to say that on the
whole those who have the surest motor control have at the same
time superior possession of their mental powers.1

When it is remembered that fatigue dethrones attention, so to
speak, it is not difficult to see why it should so soon beget stu-
pidity, since a scattered mind cannot exhibit keenness, readi-
ness, or accuracy in any of its operations. We would expect in
the first place, that perception would be less discriminating, and
this has been demonstrated by extensive investigations upon the
several senses.2 The writer has studied this subject in the
schools of Buffalo, H". Y., making use of simple experiments
which in a way tested the keenness and accuracy of interpreta-
tion of sense stimuli ; and he has found that two and one-half
hours' work in school lessens ability on the part of most pupils
to discriminate colors, as tested by sorting colored yarns, or
sounds as determined by the tone tester, or touch sensations as
determined bv the aesthesiometer, which Griesbach claims is the
best test for mental fatigue.3 The data yielded by these studies
are in general in accord with those reached by such investigators

iFor a summary of recent investigation relating to this subject, see Burk,
From. Fundamental to Accessory in the development of the Nervous System,
Pedagogical Seminary, vol. VI, No. 1, and Reprint. See also Oppenheim, The
Development of the Child, chaps. Ill, IV, V; Warner, The Study of Children,
chaps. Ill to XIII ; Donaldson, The Growth of the Brain, especially chap. XVIII ;
Halleck, Education of the Central Nervous System, chap. XI ; Mercier, The Nerv-
ous System and the Mind; Ross, Diseases of the Nervous System; Flechsig, Seele
und Gehirn, 1896; Hartwell Add. and Proc. N. E. A., 1893; Ireland, Blot on the
Brain, p. 257, et seq.

2 See for the results of some investigations : Gilbert, Studies upon School
Children in New Haven, in Studies from the Yale Psychological Laboratory, vol.
II ; Sinclair, 'School-room Fatigue, Educational Foundations, May and June, 1896 ;
Dresslar, Fatigue, Journal of the Anthropological Institute, 1888. p. 153 et seq. ;
O'Shea, When Character Is Formed, Pop. Sci. Mo., Sept., 1897 ; also, Some Prac-
tical Phases of Mental Fatigue, Pop. Sci. Mo., August, 1899.

3 Too much reliance, however, should not be placed upon the results of the
ffisthesiometric test. For myself I never could feel quite sure of my data. See
for a critical discussion of this method two articles by Leuba and Germann in
Psych. Rev., Nov., 1899.

58 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

as Kraeplin,1 Burgerstein,2 Sinclair,3 and others.4 These re-
sults will certainly not awaken surprise in any one who has ob-
served the sharpness of his own senses at different hours during
the day, and under varying circumstances with respect to fa-
tigue. One may hear those about him say frequently something
like the following : "I derive much greater benefit from visiting
an art gallery in the morning than at 4 o'clock in the afternoon ;"
or "I find more pleasure in going out into the fields and coming
in contact with nature in the morning hours than later in the
day, for I see more, or at least I appreciate more; everything
has a meaning for me now which is not apparent at other times.
There are details and harmonies in sound, in color, and in form,
which I apprehend when I am refreshed but which I miss when
my mind is tired." And the rationale of this is not obscure.
It is not that there is less of beauty and richness in nature in
the late hours of the day, nor that the visual or auditory sense
organs are incapable of receiving stimulations therefrom; but
the structures in the brain through which interpretation pro-
ceeds, because of the wastedness of their substance, if one may
so speak, and the accumulation of obstructive materials, hinder
the efficiency of the mind's action. Doubtless every student has-
noticed that when his energies are at a low ebb, Whether abnor-
mal in persisting throughout the entire day, or week, or month,
or whether occurring only at intervals in the daily rhythm, yet
in any case his perceptions become less keen and accurate, and
he grows dull in all work that depends upon clearness of per-
ception, as in the apprehension of forms in language, to some
extent in mathematics, and to a considerable degree in the me-
chanic arts, not to mention other studies.

The senses are not the only nor the principal losers when the
mind is over-wearied. Memorv, both in its retentive and recol-

1A Measure of Mental Capacity, Pop. Sci. Mo., vol. XLIX, p. 756.

2 Quoted by Kraeplin, loc. cit.

8Loc. cit.

4 Since the above was written, the writer has read La Fatigue InteUectuelle,
by A. Binet and V. Henri, in which the propositions herein set forth are in the
main substantiated. See for a recent summary of studies upon this point, Kotel-
mann, School Hygiene, chaps. VII and VIII.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 59

Jective functions, becomes baiting and unreliable. Who bas not
observed this in bis own daily experiences ? Ideas which one
bas firmly fixed in his bead, and usually bas in band when he
needs them, cannot now be readily summoned before conscious-
ness, and often keep out of reach altogether. One bas greater
difficulty, too, in making ideas fast now than on other occasions.
It seems as if the bewildering mechanism of the associative sys-
tem, regarded from the neural point of view, becomes in a meas-
ure thrown out of gear, one might say, in fatigue ; and in this
event, memory processes easy and natural in normal mentation
are so no longer. Under such circumstances one is apt to find
that making use of devices for recalling ideas that at other times
prove_ useful now are worthless. There is apparently an oblit-
eration of old mental pathways ; the energies of intellection are
not discharged in the customary grooves, and the thought life
then becomes to a greater or less degree either monoideistic or
atomistic. As Ribot says,1 "Fatigue in every shape is fatal to
memory. The impressions received at such time are not fixed,
and the reproduction of them is very laborious and often impos-
sible. . . . When the normal conditions are restored
memory comes back again."

It is not needful to linger over the significance of these facts
for the student. His success in the acquisition of learning; or
to put it in a way which would better represent the chief aim
of education, in building up a unified personality with interests
and activities adapting him most harmoniously to bis social and
natural environments, — his success in this depends so greatly
upon the power of retaining impressions and summoning them
forth when needed to guide action, that it would be impossible
to overestimate the mischief that circumstances can do which
militate against achievement of this sort. And then, regarding
the immediate demands made upon the university student in
bis class-room, it is evident that the incapacity to fix firmly and
in such a way as to be able to recall readily the ideas gained in
the different studies is a thing of serious mien, as those who
draw too heavily upon their energies in dissipation, in neglect

1 Diseases of Memory, chap. V.

60 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

of the requirements of food, air, and exercise, or in other ways,
doubtless have occasion frequently to realize.

Fatigue works most serious harm in the elaborative or re-
flective processes. Reason requires co-ordination of ideasj it
necessitates holding before consciousness in a single act of
thought two or more objects, viewing them together to discover
the relations which they bear toward one another. It can be
seen that to accomplish this requires good control and balance
neurologically, and so psychically. But this is just what fa-
tigue makes impossible, not absolutely of course, but relatively.
Any person's experiences will afford illustrations in plenty. We
all know how difficult it is, or even how impossible it is to attend
to matters requiring elaborate reasoning at a time when the vi-
talities are run low. We generally defer the consideration of
such matters until a more favorable period when mental strength
has been regained. We attack our mathematical problems in
the morning rather than at 5 o'clock in the afternoon. Even
social custom has recognized this and has assigned the later hours
of the day to occupations and pastimes requiring little concen-
trated effort of mind.

§ 5. Neural Fatigue : Emotional Effects. — It will not be need-
ful here to do more than to refer briefly to the fact that the
cerebral states which give rise to physical and intellectual in-
co-ordination and errancy have a similar effect in principle upon
the emotional life. People are generally aware of this, and they
freely condone the bad temper of individuals at certain seasons
because of their unhappy physical condition. If one studies
the matter at close range, he can see that the people who sur-
round him are sometimes transformed in temperament under
an ordeal which overdraws their account in the nervous system.
It will of a certainty impress one who will turn his attention to
the matter to observe how in a siege of neurasthenia anti-social
qualities, as irritability, jealousy, hatred, anger, and the like
take possession of an individual who in fairer weather is well
poised and not too conscious of self in relation to others in his
neighborhood.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 61

If one should seek for an explanation of these phenomena, he
would find the most rational one, and one in every way consistent
with the principles involved in the preceding discussion, in the
theory of recapitulation; which postulates that the individual
retraces in some measure and retains in his own being to a cer-
tain extent the principal mental structures, intellectual and emo-
tional, developed throughout racial history. The emotions most
prominent in earlier phylogenetic epochs have been those con-
cerned with the preservation of self against the enemies lurking
everywhere, and which constantly threatened annihilation.1 It
was self against all the world else. The development of the
altruistic or social emotions has been of very recent origin in
racial evolution ; and by virtue of a principle of heredity where-
by latest developed phylogenetic characteristics are most unsta-
ble in ontogenesis, one is warranted in holding that while the
social emotions are for the most part pre-eminent in the individ-
ual under normal conditions, yet these very emotions are most
affected, in fatigue, when the last formed and highest areas of
the brain are first disturbed in their functioning. The process
in racial ascent of gradual specialization of brain areas to take
on more and more delicate and elaborate motor and psychic func-
tions has resulted seemingly in the highest bodily, intellectual,
and emotional activities becoming so intricately interwoven that
one cannot suffer except at the expense of the others. Speaking
neurologically then,, the conditions requisite for co-ordination in
intellectual and motor activities are requisite for the efficient
control by the highest social emotions of those which are of a
lower order, and represent earlier predominant characteristics
alike in phylogenetic and in ontogenetic history.2 A matter

!One is impressed with this thought as he reads accounts of animal life in
its native wildness, — such accounts as one finds in Kipling's books, or in
Thompson's Wild Animals I Have Known, or Cornish's Animals at Work and
Play.

2 For a detailed presentation of this theory, see, Marshall: Biological Lectures
and Addresses, lecture on Recapitulation ; Morgan : Habit and Instinct, whole
book ; Drummond : Ascent of Man, whole book ; Le Conte. Religion and Evolu-
tion, p. 133 et seq. ; Oppenheim, op. cit., chaps. I and II ; Haddon : The Study of
Man, Part II ; Baldwin : Mental Development, Methods and Processes, chaps. I,
IV, XIII ; Sail : Fear, American Journal of Psychology, vol. VIII ; Burk, op. cit. ;
Pedagogical Seminary, vols. Ill, IV, V, articles on Reverie, Mental Automations;
Bullying and Teasing, Games and Plays, Truancy, etc., etc.

62 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

which is well recognized may be alluded to in this connection, —
while under the influence of alcohol,1 or in cerebral disease,2
lower and more egoistic impulses usually gain mastery of the in-
dividual ; and thus in some of their effects fatigue, cerebral dis-
ease, and intoxication seem closely related, explicable upon the
supposition that all three attack the highest levels in the brain
first and prevent, therefore, full and sure control of lower areas.

Again, it has been emphasized by students of this particular
phase of fatigue, as Cowles,3 Beard,4 Dresslar,5 and Mosso,6
that fears which in the normal life are held in check are now apt
to assert themselves and color the emotional life. There rises up
in the early stages of fatigue a sense of dread of an indefinite
something which is about to happen; and, as depletion pro-
gresses, particular objects persist before the mind and fill the
individual's life with uncertainty and apprehension. In busi-
ness the neurasthenic is afraid to assume any responsibility. In
.the class-room the pupil is unduly self-conscious and lacks con-
fidence in his own ability ; he is timid in the presence of others,
and morbidly afraid of possible criticism. In short, the vigor
of what we may call personality denoting one's psychic ensemble,
as it were, is reduced, and this is revealed in the emotional
depths as quickly, perhaps more quickly, than in any of the other
.parts of the being.

It would seem possible to explain these latter phenomena also
by the theory of recapitulation. One of the most important and
serviceable emotions in the development of the race has been
fear, manifested toward a multitude of objects incessantly
threatening danger to life and limb. These experiences have
left their trace in the nervous organism even of the human spe-
cies, and each individual must receive them as a heritage in the

xSee Wilson, Drunkenness, p. 29 et seq.
2 See Mercier, op cit., p. 308 et seq.
3Loc. cit.
4Loc. cit.
BLoc. cit.
6Loc. cit.

O'SHEA — ASPECTS OF MENTAL ECONOMV. 63

form of "broken reflex arcs"1 or "rudimentary instincts."2 In
■the normal life these reverberations of a remote past are not
distinguished because of the strong tone of the higher psychic
life ; but let this supreme self yield its efficacy at any time and
then these recrudescences from phylogenesis well up into con-
sciousness.

Lastly, it may be said, although it scarcely needs argument,
that ethical feeling, being a most highly complex social attitude
or attunement and a recent addendum to the ancestral record, is
quickly estranged by whatever disturbs the delicate normal func-
tioning of those material media through which spiritual charac-
teristics are made manifest in this physical world. Collin,8
Wey,4 Morrison,5 Wright,8 Lombroso,7 Eibot8 and Mercier,9
who have studied moral degeneracy as a social and as an indi-
vidual phenomenon, have testified in confirmation of the doc-
trine that moral obliquity is generally the accompaniment of de-
fective physical conditions, and in all probability is the legiti-
mate issue of these. When the highest and most essential cere-
bral structures become impaired through dissipation of vital en-
ergies or improper nutrition, whether due to ignorance, excess,
or asceticism, one becomes then a fit instrument for anti-social
and immoral impulses ; but let him preserve within himself as
an individual the vigor of those organs which nature has with
unending patience developed in the evolution of the race and he
will have a superior chance, to say the least, of adjusting him-
self in harmonious relations to his social environment.

iRibot.
3 Spencer.

'Papers in Penology, 1891, pp. 27-28.
♦Ibid., pp. 57-69.
"Juvenile Offenders, Part II.

•American Journal of Neurology and Psychiatry, vols. II and III, pp. 135 et
seq.

''Female Offenders.

'Psychology of the Emotions, chap. XIV.

'Sanity and Insanity, p. 308. et seq.

C4 BULLETIN OF THE UNIVERSITY OF "WISCONSIN.

CHAPTER II.

CEREBRAL HYGIENE AND ECONOMY IN- STUDENT LIFE.

§ 1. The Student's Obligations to the State. — In view of the
foregoing it ought not to be necessary to make apologies for
urging observation of the laws of cerebral hygiene and economy
by the student in his daily life, as a member at present of an
educational community, and as a leader of social progress when
his preparatory training shall have been completed. But it
is not infrequently the case that college youth manifest little
interest in that which has the appearance of relating to their
immediate well-being, physical, moral, or intellectual^ it is in->
deed esteemed at times to be a mark of superiority to show
indifference toward things of this character. It is not appar-
ently believed in a serious manner that the attainment of the
highest degree of perfection in respect of all the elements of
personality should be the supreinest concern of every individ-
ual whether within or without the university. But even if
a student cannot see that it is a duty he owes to himself to
promote in every way possible physical and mental vigor and
balance, yet as a factor in the social whole and maintained
during his educational career by the state in the hope that
he may return to confer blessings upon it, to be a guide in
morals and to make less rigorous the struggle for physical
existence — these considerations make it obvious that there ia
absolutely no course left him but to conserve his energies and
employ them to the best advantage, that he may repay the obli-
gation due the community that has favored him. In the sup-
port of the university the state provides means for a few of
its members to receive the benefits of the broadest education;
it has then a just right to demand that every individual so
favored shall profit by these opportunities to the fullest possi-
ble extent. If for any remediable cause, as dissolute living

O'SHEA ASPECTS OF MENTAL ECONOMY-. 65

or excess, causing waste of vital forces, or failure to provide
nervous energy equal to the need in profiting by instruction
here, a student does not make the most of his privileges, then
from the community standpoint such an one is apostate to his
plain and simple duty. Being a recipient of the bounty of
the commonwealth, his indebtedness to it cannot be gainsaid;
and it is a wholly erroneous conception which persists against
all reason in some university communities, especially in those
sustained at public expense, that a student is not beholden in
his conduct to any one but himself and his guardians.

§2. The Study of Psychical Processes, — Dangers, Advan-
tages.— It perhaps should be said at this time that, in general, it
cannot but prove detrimental to become too greatly concerned
about one's own physical or mental processes. One who intro-
spects much for egoistic ends can accomplish but little in
this world ; thinking all the time about life functions tends to
render them abnormal. Mature has evidently designed that for
the most part one should be interested in objects and aims
outside of self; and the machinery of the organism will run
most smoothly when it is left largely to the oversight of sub-
conscious agencies. But while this as a general principle is
of superior worth in the practical affairs of life, it yet does
not obtain rigidly as it relates to the subject under discussion, —
the most frugal and efficient methods of generating and expend-
ing nervous energy. Every one knows, to illustrate by a sin-
gle instance, that in the matter of food, which is the most im-
portant factor in the production of vital force, there are great
difficulties to be overcome in breaking away from the dogmas
and practices of tradition. But recent investigation has made
the beginnings at least of a science of nutrition, wherein are set
forth the needs of the organism that it may best fulfill its func-
tion as an instrument of mind and as a mechanism designed
to accomplish a given amount of work, and how these needs
may best be met: yet the community at large for whom alone
these things are of value, has exhibited little interest in them

66 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

thus far. While instinct may he trusted a good way in ad-
vising us what and how to eat, yet it is certainly not an infal-
lible guide, especially since it is not within its scope to suggest
improved methods of manufacturing foods, and even new kinds
of foods themselves. It merely determines sort and quantity
when articles are presented, so its sphere of usefulness is quite
limited. Again, we tend naturally in most instances to save
needless wear and tear of mind and body, yet as we shall see
later there are avenues of waste which continue to drain off much
of our energies until we get to work consciously to stop them up.
In respect to these matters, then, study cannot fail to be of bene-
fit to every person, teaching him how to make the best kind of a
machine of himself, so to speak. But when once he learns the
trick, his mind may with advantage be turned altogether in other
directions ; he need not, he must not, be in constant query re-
specting what he should eat, and how he should work.

But now we are all apt to feel and often to say that we
have thus far been steering our barks in a given direction,
and considering how the winds have favored us, and what prog-
ress we have made, we cannot think we have been on the wrong
tack. There seems to lurk within the bosom of every one of
us a conviction begotten of the tendency to regard self as the
standard of excellence, that we cannot be very greatly improved
upon; but this belief, it need scarcely be said, is rarely if
ever the result of much reflection upon one's attainments and
limitations. While one may find occasion for congratulation
that he is as well balanced as he is, and that his energies are
devoted as largely as they are to profitable production,, yet he
needs to recognize, or most of us do at any rate, that we are
hindered in a thousand directions by obstacles and restrictions
which seriously impair efficiency. Most of us probably have
little conception of what a perfect man-machine would be, one
who is thoroughly balanced in mind and body, who always
has himself well in hand, who has abundant energies for the
tasks which lie in his way. One who, looks at life as in a
process of evolution, which seems in no wise to be yet com-

O'SHEA — ASPECTS OF MENTAL ECONOMY. 67

plete, sees that in the matter of human perfection (which
means nothing more than consummate adjustment to one's so-
cial and natural environments) people may be aided in indi-
vidual cases in attaining thereunto by compliance with the nat-
ural laws to which harmonious adjustment is required! This
conception leads one to believe in the possibility of continuous
improvement, while at the same time holding securely to all
that has been accomplished, and being devoutly thankful there-
for.

§3. The Educator s Concern With Cerebral Hygiene. — Such
a bulletin as this would doubtless not be necessary if there were
persons in the community whose special interest and duty it
was to bring the matters herein discussed in their practical
aspects to the attention of the people at large. But there are at
present few such persons in any community, and in most places
there are none at all. One would naturally suppose that these
affairs would lie within the domain of the physician; but as
a matter of fact physicians have hitherto been dealing largely
if not entirely with disease, with therapeutics, while the thing
we are considering is of a wholly different character. One's
energies may run out on the debit side for so long a time,
without proportionate income on the other side, that hostile
forces overpower him; disease seizes upon him, and then the
physician seeks to aid him in winning back wasted strength.
But it is a far cry from the highest efficiency of mind and body
to that disintegrated condition realized in actual disease. One
may be living on a low plane so far as the generation and
conservation of vital energy is concerned, and yet not come
under the eye of the physician. The M. D.'s have not yet
dealt largely with the subject of nutrition for healthy beings;
and they have only glanced by the way at all the various ave-
nues through which energies are dissipated in prosecuting the
work of daily life. Indeed, medicine seeks to cure, not to pre-
vent, nor to raise the general level of organic life. A few medi-
cal writers have, however, given these matters some attention,

68 BULLETIN OF THE UNIVERSITY OF "WISCONSIN.

but it would require little space to enumerate them and tell what
the j have done.1

As things stand at present it falls to the educator to con-
sider some of these physical phenomena which directly deter-
mine the fruitfulness of his teaching. It was generally thought
in older times when the relation of mind and body was quite
differently understood, that the teacher's duty was fulfilled
when he simply offered mental aliment to his pupils. If they
did not receive and digest it, he sought to aid them in the
process by generous stimulation with the cane and the birch.2
But inl our own day an intelligent teacher knows that when
his pupil is lacking in available cerebral energy his instruction
will be of little avail, either in cultivating the intellect or in
fashioning character; and he ascribes shortcomings more often
to defective physical conditions than to lethargy or perverse-
ness of the will. He sees then the necessity for considering
those factors which inevitably decide whether what he presents
will be wrought into the mental structure of his pupil or whether
it will simply be an added load to an already overburdened
mind, — overburdened because of deficiencies in the neural
structures through which it is manifested and by which it is de-
termined.

§4. Studies at the University of Wisconsin: Purpose and
Methods. — Holding these views the School of Education, at the
instance of the writer, sent out to all students in the University
of Wisconsin, in the spring of 1898, a questionnaire relating to
the subjects discussed in the preceding paragraphs, — the modes
of producing cerebral energy and conserving it so that it may
as fully as possible be expended in profitable directions. The
primary purpose of the questionnaire was to turn the thoughts

*The best work with which I am familiar is Stevenson and Murphy, op. cit, 3
vols. This is not adapted, however, for general reading ; nor does it devote
much attention to mental hygiene and economy. Other good works are Parks :
Practical Hygiene; Wilson: Handbook of Hygiene and Sanitary Science; Rohe:
Text book of Hygiene. Carpenter's Physiology has some very good hints on hy-
giene. Martin : The Human Body, chaps. XX, XXI, and XXIX discusses In a
scientific and practical way some of the problems herein considered.

2 See a most interesting book, — Cooper: The History of the Rod.

O'SHEA — ASrECTS OF MENTAL ECONOMY. t)9

of students to a consideration of the hygiene of food, exercise,
ventilation of living and sleeping rooms, the arrangement of
the daily program, the use of particular materials in writing,
and similar matters of practical importance; and it was hoped
in addition to obtain statistical data relating to these affairs
which would be of some local, and perhaps also of general in-
terest. The questionnaire, with the explanatory letter, follows :

Madison, March 5, 1898.
The accompanying circular is sent you in the hope that you may be
able to give me some exact information respecting your mode of life
in the University. This is not requested for any personal reasons what-
ever; but it is desired simply to be collated for scientific purposes with
similar data gained from other students. In the course in Child-Study
much attention is given to the subject of mental hygiene and economy
during the period of school and college life; and it is the plan to use
the information obtained from the responses to this circular in the
regular Child-Study work, and as the basis of a bulletin to be issued
later for the guidance of students in respect of the important matters
referred to herein. It is the purpose to present in this bulletin the
results of research regarding the manner in which one's daily life
should be ordered so that he may do the greatest amount of intellectual
work with the least expenditure of energy, and without endangering
mental health and poise; but in order that local conditions may be
made more suitable, if desirable, for student life, it is needful that those
conditions be understood just as they exist. I trust, therefore, that you
will answer the enclosed questions as fully, and particularly as ac-
curately, as possible. If you are not sure in any of your replies, say so.
If there are any questions you do not care to answer, omit them; but
I wish to assure you that your name will in no case be known to
any one but myself and my assistant, and it is recorded simply as a
guarantee of earnestness and good faith in the replies. If your an-
swers are referred to for any purpose whatever it will be by number.
Please to return the circular in the enclosed envelope as soon as you
can conveniently supply the information requested. Drop the en-
velope in one of the boxes labeled "Child-Study" in Library, University,
or Science Hall. Be as complete and detailed in your answers as your
knowledge will warrant, using more paper if necessary.

Very respectfully yours,

M. V. O'Shea.

70 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

CIRCULAR.

I. Food :

1. Under tEe headings Breakfast, Luncheon, Dinner, please write in detail
what you customarily eat and drink at each meal.

If possible, keep account for a week and indicate number of times each article
Is eaten ; thus : oatmeal, 7 ; beeksteak, 5, etc.

Be specific regarding the quality of each article, as bread: graham, whole
wheat, white, rye ; meat : beefsteak, roast beef, roast chicken, enumerating each
separately.

Indicate also, as accurately as possible, in what manner and how thoroughly
each article is cooked. Observe particularly whether the meat is boiled, broiled,
roasted, or fried ; how long the oatmeal and other cereals are cooked, whether
over night or only for an hour or two in the morning ; whether the bread is light
or heavy, etc. (Your landlady will doubtless gladly inform you upon these mat-
ters if you ask her, and she will probably be pleased to note your interest in her
culinary enterprises.)

2. What articles of food do you like best? What ones really form the sub-
stance of your dietary? Do you eat between meals, indulge in midnight lunches,
etc.? Do you have dinner at midday or at night?

II. Sleep :

1. Do you sleep soundly? Dream much? How many hours do you plan to
spend in sleep? How late do you study at night? When do you go to bed ?
What time do you arise in the morning?

2. Have you ever studied all night, or nearly so? What effect did it have
upon you? Has knowledge gained at such time been enduring?

III. Study :

1. How many hours per day? What are your study hours? Are they regular
and uninterrupted, or otherwise? How many hours may you count upon with
certainty to be entirely uninterrupted during the day? During what hours of
the day are you at your best? When are you dullest? Do you stimulate your-
self artificially to study? If so, how?

2. Indicate the amount of time you spend upon each of your studies? How
many hours of written work each day? Pen or pencil? If pen, fine or blunt
point? Metal holder? If pencil, soft or hard?

IV". Health :

1. Headaches? Indigestion? Colds?

2. Have you had your eyes examined by a skilled oculist?

3. Indicate time spent by you in gymnasium : in open air.

4. Do you dance? How frequently? How late?

5. Do you smoke? Cigars, Cigarettes or Pipe?

V. In General :

What do you pay for board? For room? How large a room have you? How
many in it? How heated? How ventilated? Do you board yourself? Do you
do your own washing? How much work, manual or otherwise, do you undertake
outside of your University duties?

A few words respecting the distinct purpose of this study and
the method of its prosecution should be added here. In the first
place, it was fully realized that it would not be possible to obtain
a great body of accurate, scientific information by this method,
especially in regard to the subject of food, in respect either of
quantity, quality, or the character of its preparation for utiliza-

O'SUEA — A8PECTS OF MENTAL ECONOMY. 71

tion in the organism. Xo effort was made to ascertain how much
food was eaten, for the reason principally that such a request
could not be complied with; and this information was not partic-
ularly desired anyway since there was no intention of enquiring
in minute detail into local practices because of the vast
amount of labor it would entail without being of great value.
What was wanted was a general -rar^ment of the articles of
food which form tin- substance of students' dietaries; and it was
thought to be sufficiently definite for the purposes of the study
to assume that the amount and quality of the articles consumed
would be such as have been commonly found to be the case else-
where. Regarding the subject of cooking, it was not hoped that
exact data could be obtained, since it would be difficult for stu-
dents to determine this with absolute accuracy. It was thought,
however, that some reliable impression could be gained, especial-
ly of the cooking of starchy foods and of the especial manner of
preparing meats. The results have realized all that was antici
pated, although in some instances the answers were for the most
part useless except as they could be interpreted from other papers
that were written by >tudents living under similar conditions, —
obtaining their food at the same table, for example, and dwelling
in the same house. In the interpretation of data the writer
makes use of his own observations gained while visiting several
hoarding clubs and restaurants. His experience, it may be
added here, has substantially corroborated the results obtained
from the questionnaire.

The data furnished in response to questions relating to ex-
ercise, habits of eating with respect to hours and irregulari-
ties, the size, heating, and ventilation of living rooms, the ar-
rangement of the daily program, the employment of writing
materials and the like, are more complete and definite and are
reasonably satisfactory. The information respecting health,
however, is probably only in a relative way of value, since stu-
dents are not able to observe sueh matters with scientific accu-
racy; and they, in common with other people, are not good
judges of their own status in this regard anyway, since they
have no standard for measurement except their own expe-

72 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

rienoes, which are too apt to represent to them normal condi-
tions, however far they may be from this. It was expected,
though, that the data here would be valuable only in a general
way as indicating instances of important abnormal conditions
which interfere with the efficiency of the individual's work.

While it was hoped to gain from the investigation some re-
liable estimate of the energeic aspects of student life in
our community, yet the primary object after all in asking
students to report the practices of their daily lives was (and
this has been already said) to direct their attention to a few
of these vital things in the belief that this in itself would serve
to correct some wasteful habits. It was thought it would
be of value, also, to suggest to students the necessity of intel-
ligently arranging their dietaries so far as they could control
the matter, with the purpose in view to provide the largest
amount of energy at the least expense, whether regarded from
the point of view of the effort required to transform certain
foods into nervous force, or of the apparently more practical
aspect of the financial outlay. This expectation has been real-
ized in a measure at least, since there has come to the writer
trustworthy evidence that the questionings of students in re-
gard to the articles of food and cooking has resulted in some
improvement in both directions. It was believed, finally, that
this would be a good way in which to prepare the minds of stu-
dents for the discussion of the subject of mental economy, which
is the raison d'etre of this bulletin.

The labor of collating the returns was so great that it was
found impossible to examine but 316 papers.1 Care was taken,
however, to select those which represented customs and prac-
tices in the different phases of university life, and it is doubt-
ful if there would have been any special advantage in the exam-
ination of a much larger number; the conclusions regarding
local manners and methods would probably not have been mate-
rially altered therebv

JThe statistical part of the work was done under my direction by Mr. F. J.
Wojta.

I

O'SnEA ASPECTS OF MENTAL ECONOMY. 73

CHAPTER III.

EELATIVE VALUE OF FOODS IN THE PRODUCTION OF NERVOUS

ENERGY.

§1. Philosophy of Nutrition. — It is no doubt known to every
one that the primary function of food in the system is to sup-
ply the force or forces required for the maintenance of the
activities of life. The organism may be considered from this
point of view as a mechanism designed to accomplish a certain
amount of work, physical or mental ; and in effecting this the
energy represented in the thing done, including all accessory
expenditures and waste, must balance that expended by the doerr
thus conforming to the principle of the conservation of energy.
The work thus required to be performed by every organism
and entailing dissipation of vital energy may be regarded as
of two kinds; in the first place the body must be kept up to
a temperature quite above that of the environment in which
it is ordinarily placed, and a large amount of force must there-
fore be transformed into heat. Then there is in every instance,
though differing with different people, a characteristic amount
of energy employed in muscular and mental activity. In these
two directions force is being constantly utilized, and it must
be as constantly replenished by the processes of nutrition if
life is to be maintained

The factor of heat seems to be a practically uniform one
for all people, since if in any case the body fall far below a
certain standard the delicate adjustments essential for the per-
petuation of the organism are disturbed and physical annihi-
lation ensues. And by virtue of a comprehensive law of be-
ing, whereby all possible effort will be made to prevent the
dissolution of life, the organism will strive in every way to
supply the necessary energy for the preservation of normal

74 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

temperature ; and when needed it will draw upon the credit of
the muscular and nervous systems, since one can survive with
a relatively small amount of either motor or mental action.
When, then, it may be remarked by the way, the body is not
properly protected in cold climates, the energy which is gener-
ated in the system will be dissipated in comparatively large
ratio in the effort to keep warm; and, as a consequence, less
force can be utilized in the kinds of work for which in reality
the organism exists ; for in the highest forms of life, whatever
may be true of those lower in the scale of existence, the ulti-
mate purposes of existence are very clearly of a mental order.
And in the attainment of these, motor processes are for the
most part essential. So that in man mental and motor activi-
ties are of primary importance, regarded from the point of
view of the raison d'etre of the organism, as well as from the
testimony of introspection and of the desires of the human
heart.

In addition to the purposes of nutrition already indicated
there, should be mentioned one other. In a growing structure,
where continual increase in size and weight is taking place,
there are required nutritive substances other than those utilized
in carrying forward somatic and psychical functionings. There
are needed substances for augmenting the bulk of bone and
nerve and muscle, — 'materials for construction, that is to say.
In adult life, however, when growth has been completed, there
is no longer a demand for materials to build up, but only to
repair the wear and tear of mind and body ; so that in maturity
we may take account principally of the requirements of the
organism for the generation of force employed in the prosecution
of mental and motor enterprises.

To return to our first proposition, the energy demanded to
sustain the activities of life must be supplied in the food stuffs
which are eaten. Now it is probably well known that various
food elements are required to meet the different needs of body
and brain. The nutrients best suited to furnish the materials
employed in making bone and muscle are not alone sufficient to

O'SIIEA — ASPECTS OF MENTAL ECONOMY. 75

promote cither muscular or mental action ; and those adapted to
supply physical power in Largest measure are not in all cases the
ones from which to gain cerebral energy most advantageously, as
will be demonstrated more fullv later. It should be noted here,
however, that we say just the ones, for in some degree the energy
of the entire organism may on occasion be drawn upon for the
maintenance of either mental activity, motor activity, or tem-
perature. This is indicated in the fact that arduous manual
labor lessens the vigor, keenness, and duration of intellectual
processes,1 and reduces the temperature of the body. And in
the same way intense and long continued mental application
reduces the power of motor execution,2 and, as in muscular
labor, makes heavy demands upon the calorific condition of the
system.3 Spencer4 called attention to this some time ago, and
insisted that excessive brain work was causing physical dete-
rioration in the English people. Mosso5 maintains that severe
brain work makes so great a demand upon the energies of the
body that the muscles sacrifice a part of their albuminous con-
stituents that mental activity may be sustained.

And yet there is a limit to the convertibility of the energies
of the organism. One may be in good flesh and yet be under-
nourished nervously. Warner,6 in his inspection of the school
•children of London, has frequently found instances where there
was every evidence of adequate bodily nourishment, and yet
nerve signs revealed a depleted condition of the brain. A few
years ago there came under my observation in the city of Buf-
falo two children who gave their teachers and parents much
trouble on account of their irritability and the slow progress
they made in their studies. They appeared outwardly to be
well nourished ; but finally upon expert examination it was

1 Curtis, Pedagogical Seminary, Vol. VI. VI, No. I, p. 78, quotes Mosso as saying
that he has several times climbed to the top of Mount Blanc, but he can remem-
ber nothing of the view. He has a friend who has to write down his impressions
■on his way up or he can retain nothing.

2 Mosso loc. cit.

sSee an Instance of lack of sleep causing marked fall in temperature. Peda-
gogical Seminary, Vol. VI, No. 1, p. 81.
^Education, p. 260 et seq.
8 Loc. cit.
'Mental Faculty, pp. 79-80.

76 BULLETIN OP THE UNIVERSITY OP "WISCONSIN.

found that the blood was deficient in the elements required for
adequate cerebral nutrition, and a special diet was resorted to.
In a few weeks the children had noticeably improved in their
emotional activities and in their intellectual work.

While, then, the production of energy for mental activity isr
for the most part, simply one phase of the general problem
of generating force for all the needs of the organism — the brain
drawing its quota out of the common stock — yet in some meas-
ure this demands particular consideration. At the same time
we must recognize with Warner, x that one probably never finds
a vigorous brain in a starved body ; so that in aiming to pro-
duce cerebral energy we must see to it that the organism in toio
is well provided for, which requires that we consider the sub-
ject of nutrition as a whole.

It seems almost superfluous to say that the ideal dietary is
one which will just meet the needs of the organism; it will
not supply more nor less nutrition than can be profitably util-
ized. Overeating results in burdening the system, and so lim-
iting its efficiency; undereating fails to supply fuel enough to
keep the machinery of life in motion. There should indeed
hang over each man's table the motto, "Eat to live, so that every
power will be at its best ;" and if this be made the rule of life
one's board will afford the foods which his occupation specially
demands. If he be an outdoors-man he must have more con-
structive and calorifacient material than if he live a sedentary
life. If he be a student, fond of vigorous physical exercise for
a few hours during the day, he will need to make more promi-
nent in his dietary the reparative and heat-affording foods than
will his lethargic, inactive classmate. When these individual
needs are not recognized and the same regimen is provided for
all with little opportunity for selection, then plainly some must
suffer ; there will be those who will be either overfed or underfed.

It has already been indicated that different food-stuffs contain
different nutritive elements, and in order to secure proper nu-
trition they must be combined ■with one another in such a man-

JOp. cit., p. 79.

O'SHEA A8PECTS OF MENTAL ECONOMY. 77

Tier as to preserve right proportions between them in ministering
to the needs of the organism, no matter whether we depend upon
appetite, chemical analysis, or custom as our guide; a point
which will receive fuller discussion in another place. The prin-
cipal constituents of foods are: fats, carbohydrates, albumen (or
protein), and salts ;* and the uses to which each of these are put
in building up, repairing, and sustaining mental and motor ac-
tivity are satisfactorily stated by Church,2 whose treatment of
the subject may here be adopted.

Class I. — Nutrients.

Division 1. — Incombustible Compounds.

Group i. Water — The carrier of nutritive materials and waste prod-
ucts; forms an essential part of all tissues; is present in large
proportion where change is most active.

Group ii. Salts or Mineral Matter, such as common salt and phosphate
of lime, which serve to effect changes and build up certain tissues.

Division 2. — Combustible Compounds.

Group iii. Carbon Compounds, such as starch, dextrin, sugar, and fat,
which serve to keep up the heat and movements of the body by
the discharge of their potential energy during oxidation in the
organism. The fat of the body is formed in part from fat or oil
in the food. The members of this group are often called "heat-
givers," a term which is equivalent to "force-producers."

Appendix to Group iii. Gum, mucilage, and pectose, approach starch in
chemical composition, and probably serve the same end. Cellulose
may be named here, but its value as a nutrient is doubtful.

Group iv. Nitrogen Compounds, such as albumen, myosin, and casein,
the chief formative and reparative compounds of food; they also
may yield fat, and by their oxidation set free heat and motion.
They are often named "flesh-formers," while the group is known
as albuminoids.

1 Martin, Human Body, chap. XXI, employs a more detailed classification, but
it is common now among writers on dietetics to speak only of the four great
classes of nutritive elements, and this will be deemed sufficiently detailed for our
purposes.

iFood, p. 9, (London, 1889, Chapman and Hall).

78 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

Appendix to Group iv. The ossein of bones and gelatin; cartilage and
chondrin; keratin and elastin from skin and connective tissue, —
approach the albuminoids in composition, and may serve in a
measure, some of the same purposes in the body as those to which
the true albuminoids are applied. This series of compounds may
conveniently be designated the osseids.

Class II. — Food Adjuncts.

Group i. Alcohol, as contained in beers, wines, and spirits.

Group ii. Volatile or Essential Oils, and other odorous and aromatic

compounds, as contained in condiments, like mustard and pepper,

and in spices, as ginger and cloves.
Group iii. Acids, as citric acid in lemons, malic in apples, tartaric in

grapes, oxalic in rhubarb, and acetic in vinegar and pickles.
Group iv. Alkaloids, as caffeine in coffee and tea, theobromine in cocoa,

and nicotine in tobacco.

§2. Statistical Summary of Studies on Foods. — With this
word upon the subject of nutritive values in general the returns
from the questionnaire relating to food may be presented. The
figures denote the number of times the various dishes were eaten,
in a single week, and indicate simply the relative frequency with
which certain articles of food are found in our students' dieta-
ries. From an examination of the tables and individual diet
lists it will become evident, and this is a point worth noting ear-
ly, that brain workers in our community have set before them
substantially the same bills of fare that manual laborers do, or
that they discussed themselves when they were upon the farm,
living an active out-door life.

The different articles of food arranged according to their rela-
tive frequency in dietaries are given below. The returns do not
indicate the precise days of the year upon which records were
made ; but it may be sufficiently definite to know that the blanks
were distributed on March 23, and were all returned by
April 27 :

O'SIIEA — ASPECTS OF MENTAL ECONOMY.

79

Breakfast.

Kind of Food.

No. Times
Served.

Kind of Food.

No. Times
Served.

1,380
1,189
1,088
812
757
752
704
677
646
586
536
442
293

14 Fork-teak

233

15 Rice

145

3 Coffee .

16 Pie

104

4 Eccs. fried .

78

5 Fruit

78

6 Butter

19 Fish

73

7 Milk ..

62

8 Beefsteak .

59

9 Potatoes, fried

58

10 Potatoes, baked

52

It Toast . .

38

12 Graham, bread. .

25 Eggs, poached

27

26 Rye, bread

12

Dinner,

Articles of Food.

No. Times
Served.

Articles of Food.

No. Times
Served.

1 Bread, white

1,067
844
716
7C0
6S8
683
604
588
440
431
375
356
333
238
219
215
200

18 Corn

199

2 Milk

19 Cranberries

195

3 Vegetables

20 Eggs, fried

188

4 Potatoes, fried

21 Peas

183

5 Fruit

22 Tea

182

6 Bread, graham .

24 Veal, boiled

176

7 Pie

172

164

9 Roast pork

26 Preserves

150

10 Pudding

27 Fish, fried

149

11 Cake..

28 Mutton

147

12 Coffee

29 Ice cream

131

13 Sauce

30 Cheese

31 Crackers, soda

127

115

15 Roast chicken and turkey . .

16 Soup

32 Salmon

33 Tongue

88
54

17 Beans

34 Oysters

41

80

BULLETIN OK TIIK UNIVKUHITV OF WISCONSIN.

Luncheon,

artiole of Food

Ni>. Time
Served.

1 Breadi white

2 Potatoes, fi Led ,

a Miik

4 Cake

:. Bread, graham,

6 Potatoes, baked.

7 Banoe

8 Fruit

9 Vegetables

10 Colli bam

n Biggs, fried

12 Tea

13 Batter

14 Coffee

15 Roast beef

16 Pie

n Beefsteak

18 Preserves

9i:t
<wo

050
R86

594
5."i2
5115
516
468
417
402
401
389
338
255
258
247
222

Articles of Fin nl.

19 Bisoultt

20 Pudding

21 Crackers, soda

22 Toast

23 Sausage

24 Chocolate

25 Oysters

26 Chicken and turkoy.

27 Soup

28 Fish

29 Strawberries

30 Potatoes, mashod ...

31 Mutton

32 Ico croam

33 Roast pork

34 Tontftio

35 Honey

No. Time

Sei vod.

217
186
188
186
180
174
174
172
166
160
155
155
134
131
111
63
17

Samples of fche bills of fare Berved in the various places where

Students obtain meals are offered to show individual differences,

and to be used Later in computing the nutrient, value of these

typical rations.

Ch<l> Hoard— Questionnaire No. 1101.

Breakfast.

Oatmeal 4

Pounded wheat 2

Coffee 7

Pork, fried 8

Roast, beef ■*

Biggaandham l

White broad 5 or 6

Qraham bread 2

Potatoes 2 or 3

Milk 2or3

Wheat Hour cakes 1

Luncheon.

Potatoes, fried 7

Mash 2

Beef, boiled 3

Veal, fried 2

Milk 7

White bread 7

Cake and sauco 4

Cabbage, boiled 3

Fried orrs 3

Batter 7

Strawberrj diorteako. 3

Dinner.

Meats— Chicken, roast. .. 1

Beef, boiled 3

Pork, boiled 2

Veal 1

Potatoes, boiled 7

Lettuce 4

CabbaRo, boiled 3

Bread, white 3 or 4

Corn, boiled 8

Milk 7

Pie 5

Padding 2

Biscuits and honey 2

o'hiiea — ASPECTS 01 MENTAL ECONOMY.

81

Prix ate Board- No. 1526.

r.fai-t.

Oatinca), cooked 'i"> mlontea.

Beefsteak 4

Panaakea i

Bread and bnf I

Milk, Water.
Su^ar.
Salt.
MuHtanl.

Laur)ii-.,ij.

Milk.

Prt d Pork.

White bread.

Sauce.

Cake

■ illy,
rkrout.

ter.
Lettuce, occasionally.

Wat/r.

Dinner.

('.read and bill I
Sugar.

Cora.

La nb 1

M ll >'.n 1

f bicken 1

1

Tomatoee, oceaelonallr.

Sut'ar.
Halt.

Pepper.

Restaurant -.No. 1440.

Breakfaet.

Oatmeal 7

Wheat bread 7

3

Pancake* 1

Coffee 7

Sugar 7

Koatst pork 2

Boa t Seel '<*

Graham bread 2

Fried eakei 8

Potatoes 7

Batter 7

Luncheon.

Potatoei 7

Coffee 7

Cold beef 2

Ekkb 2

1

Whit<- bread 7

am hrea 1 4

Rye bread '.',

Sugar 7

Batter 7

AMjlf-f, 3

Kananan 8

gee 1

Linner

BODP

Boiled beef

Piafa

Potatoei

Gravy

White bread

p.rown bread

liye hread

Pie

Beaoi

Kraut

Tornatoefc, boiled .

Par nir,H

f l.eehe

Let'uce

82

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Ladies' Hall— No. 1027.

Breakfast.

Coffee 7

Toast 5

Potatoes, fried 2

Beefsteak, fried 2

Ginger bread 2

Sauce 1

Eggs, poached 1

Doaghnnts 1

Luncheon.

Milk toast 1

Cold beef 1

Chicken, cold 1

Ham 1

Cheese 1

Strawberries 2

Cake 5

Tongue 1

Potatoes, fried 2

Radishes 1

Honey 1

Milk 7

Sauce 7

Hot breads 3

Cold breads 4

Olives 1

Chocolate 7

Butter 7

Corn 1

Dinner.

Parsnips, fried 7

Pickles 3

Boiled beef 1

Beefsteak, fried 3

Lettuce 1

Tomatoes 1

Pie 1

Cheese 1

Canned peas 1

Chicken, fried 2

Sauce 3

Potatoes, boiled 1

Bread 2

Butter 7

Ices and creams 2

Cake 2

Pudding 2

Fruit and cream 1

Beans 1

Onions 1

Meats not very well done. Bread neither heavy nor light, but rather medium.

The articles of food which are actually eaten most largely are
indicated in the answer to the question, What foods really form
the substance of your dietary ? One hundred and nine answered
meats and vegetables, without specifying the kinds of each.
Eighty-five live principally on oatmeal, according to the returns ;
85 on bread and butter; 80 on potatoes ; 71 on eggs ; 76 on roast
beef.

§3. Composition of the Food-stuffs Found in the Tables. — In
order to pass judgment upon the value of these dietaries, either
as a whole or individually, it is necessary to know what nutritive
ingredients the various articles mentioned afford. It is doubt-
less impossible to determine this exactly by any known methods

O'SEIEA — ASPECTS OF MENTAL ECONOMY.

83

of calculation, since the element of life in general and individu-
ality in particular/ which cannot be precisely reckoned with in
our present methods of scientific experiment, probably modify
in some measure the value of a food as it might appear when
subjected to chemical examination. But chemical analysis can
ascertain with accuracy the composition of any food, and this
has been relied upon for a long time as a measurably safe index
to the worth of any article. It is certainly not an overstatement
to say that it is a reasonably reliable and serviceable method of
determination. Granting an unknown and indeterminable fac-
tor in estimating the nutritive value of any food, yet chemical
analysis would enable us to say this much at least, — that there
are certain things in which it would be impossible, considering
the limitations of the human digestive apparatus, to get sufficient
albuminous elements, for instance, to support active, vigorous
life ; while in others, if eaten exclusively or even largely, albu-
men would be gained in excess. In this way, though the for-
mulas obtained from chemical analyses do not represent the
exact value of milk, for instance, as it will be received by the
stomachs of different persons, yet, to repeat, it does indicate the
substances from which the several elements may be derived most
easily and economically, and this will give enough play to in-
dividual preferences and idiosyncrasies in digestion and assimi-
lation. It should be said, too, that while the organism requires
a certain quantity of fats, carbohydrates, and albumen, yet the
administration of these in pure form would not serve to properly
nourish a person. The nutrition which they contain is yielded
only when they are obtained in an organized state as they are
found in nature in the fruits, seeds, etc., of plants and in the
flesh of animals.

The composition of foods as given by various investigators,
while differing in some cases in slight degree, are yet for all
practical purposes identical. The most satisfactory analyses

i Charts showing differences between individuals in digestive characteristics,
for instance, are shown further along, in Chap. VI.

84

BULLETIN OP THE UNIVERSITY OP WISCONSIN.

with which the writer is familiar are those made by Jordan,1
'Atwaiter,2 Church,3 Smith,4 aiud Kellogg.5 The tables by At-
water are given below :

•g.3

Edible Portion.

Food Materials.

s.

a

Nutrients.

Fuel

Total

Pro-
tein.

Fat.

Car-
bohy-
drates.

Min-
eral
mat-
ters.

value

of 1

pound.

Animal foods, as purchased.
Beef:

Pr ct.

20

12.6

14.6

21

19.5

7.8
19.2

5
12.1

17.9

16.3
18.1

15.8
17.3

14.6
11.4

38.2

32.4

13.7

66.8
48.6
29.9
50.1
44.8
17.7
35.3
42.1
50.9
40.4
4.9
62.1
82.3

Prct.

49.6

55.8
49.5
38.2
48.3
60.9
44.3
70.8
43.7

56.7

49
50.6
41.5
44.2

43

36.8

44.6
44.7
63.1

27.2

43

58.5

35.2

40 4

61.9

40.6

40.5

19.2

28.1

59.3

31

15.4

Prct.

30.4
31.6
35.9
40.8
32.2
31.3
36.5
24.2
44.2

25.4

34.7

31.3
42.7

38.5

42.4

51.8

17.2
22.9
23.2

6

11. 1
11.6
14.7
15

20.4
24.1
17.6
29.9
31.5
35.8
6.S
2.3

Pr ct.

15.6

17

15

12.2

15

18

13.9

16.7

12.4

16.6

15.1
15

12.6
14

13.6
14.8

15.1

16.1

12.1

5.2

9.8

10.6

9.2

10

15.1

14.3

16

20.2

14.7

19.3

5.5

1.1

Pr ct.

14

13.7
20.1
27.9
16.4
12.3
21.8
5.1
29.2

7.9

18.8
15.6

Prct.

Prct.

.8
.9
.8
.7
.8
1

.8
2.4
2.6

.9

.8
.7
.6

.8

.8
2.4

.9

.9

.9

.5
.7
.8
.7
.7
.9

1

1.2
.9

1.7

1.2
.6
.4

Cal.

880

895

1,125

Rib

1,405

970

Round steak

Flank, corned

855
1,180

525
1,460

Mutton :

Shoulder

640
1,075

935

1,480

Pork:

Shoulder roast, fresh

23.7

28
34.6

1.2

E.9
10.2

.3

.6

.2

4.8

4 3

4.4

8.8

.4

8.8

15.1

15.3

.7

.2

.1
.6

1,260
1,435

Ham, salted, smoked

1,735

330

550

Eggs, in shell

655

Fish, etc. :

Flounder, whole

110

Bluefish, dressed

210

Codfish, dressed

205

Shad, whole

375

Mackerel, whole

365

Halibut, dressed

465

Salmon, whole

635

Salt mackerel

315
745
910

Canned salmon

1,005

135
40

1 Jordan: Dietary Studies at the Maine State College in 1885, published by
Washington Government Printing Office.

*Atwater: Foods; Nutritive Value and Cost, Washington Government Print-
lng Office.

* Church :

4 Smith:

B Kellogg

Food, Chapman and Hall, London.
Foods, D. Appleton & Co., New York.
Publications of the Laboratory of Hygiene

of the Battle CreeK

(Mich.) Sanitarium.

O'SHEA — A9PECTS OF MENTAL ECONOMY.

85

Composition of foods— continued.

6
ft

: —
.a a
Cs

- Z

- -s

EDrBLE POETION.

td

Nutrients.

Fuel

Total

Pro-
tein.

Fat.

Car-
bohy-
drates.

Min-
eral
mat-
ter.

value

of 1

pound.

Animal foodst edible portion.

Beef:
Neck

Prct.

Pre?.

62

63.9

58

48.1

60

63.2

54.8

58 1

49.8

68.8

58.6
61.8
49.3
53.5

50.3
41.5
12 1

41.5

62.4

72.2
66.2

73.8
87
10.5
11

30.2
41.3

84.2
81.7
82.6
70.6
73.4
75.4
63.6
53.6
34.6
43.4
87.1

Prct.

38
38.1

42

51.9

40

31.8

45.2

41.9

50.2

31.2

41.4

38.2
50.7
46.5

49.7
58.5

37.9

58.8
37.6

27.8

33.8

26.2

13

89
89.5

69.8
58.7

15.8
18.3
17.4
29.4
26.6
24.6
36.4

12.9

Prct.

19.5
19.5
17.6
15.4
18.5
20.5
17.2
13.3
14.2

202

18.1

18.3

15

16.9

16
16.7
.9

13.8

18.8

24.4
23.9
14.9

3.6

1
.6

2S.3
38.4

13.8
16.8
15.8
18.6
18.2
183
21.6
21.4
36.4
17.3
6

Prct.

Prct.

Prct.

1

1
.9
.9
.1

1.2
.9

2

3

1.2

.9
.9

.7
.9

.9
2.7
4.2

2.2
3

1.4

1.2
.8
.7

3

3

4.2
4.6

1.3
1.2
1.2
1.3
1.3
1.1
1.4
1.6
1.5
2.6

Cal.
1,100

15.6

1,020

1,320

Rib

85.6

20.5
10.1
27 1
26.6
33

9.8

22.4

19

35

28.7

32.8
39 1

82.8

42.8
15.8

2

8.7

10.5

4

85

85

35.5

6.8

.7

.3

.4

9.5

7.1

5.2

134

.3

15.8

26.4

1.2

4.7
.5
.4

1.8
8.9

1,790

1,210

805

1,465
1,370

1,655

790

Mutton :

1,280

1,140

1,755

Pork:

Shoulder roast, fresh

1,525
1,680

1,960

Fat, salted

3,510

Sausage :

Pork

2,065

1,015

540

810

721

Milk

325

3,615

3,605

Cheese :

Full cream

2,070

1,165

Fish:

285

325

Codfish

310

Shad

745

640

Halibut

560

965

410

1,345

1,860

3.71 2

230

86

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Composition of foods— continued.

QJ CD

e -

OS

—J
«<"

Edible Portion.

Food Materials.

u

2

C8

Nutrients.

Fuel

Total

Pro-
tein.

Fat.

Car-
bohy-
drates.

Min-
eral
mat-
ter.

value

of 1

pound.

Vegetable foods.

Prc«.

Pre*.

12.5
13.1
13.1

14.6
7.6
15
12.4

12.3

12.6

78.9

71.1

89.4

88.6

87.6

87.2

78.1

81.3

96

91.9

83.2

2

24.6
32.3

8.3

Prct.

87.5

86.9

86.9

85.4

92.4

85

S7 6

87.7

87.4

21 1

28.9

10.6

11.4

12 4

12.8

21.9

IS. 7

4

8.1
16.8
98
75.4
67.7
91.7

Prct.

11

11.7
6.7
6.9

15.1
9.2
7.4

26.7

23.1
2.1
1.5
1.2
1.1
1.4
2.2
4.4
2.8
.8
2.1
.2

Pr ct.

1.1

1.7

.8

3.4

7.1

3.8

.4

1.7

2

.1

.4

.2

.4

.3

.4

.6

1.1

.4

.3

.4

Prct.

74.9
71.7

78.7

76.1

68.2

70.6

79.4

56.4

59.2

17.9

26

8.2

8.9

10.1

9.4

16

13.2

2.5

5.5

15.9

97.8

73.1

56.3

68.7

Prct.

.5

1.8
.7

1

2

1.4
.4

2.9

3.1

1

1

1

1
.6
.8
.9
.6
.3

1.1
.3
.2

2.3
.9

2.4

Cal.
1,645

1,625

1,625

1,605

1,850

1,645

1,630

1,565

1,615

375

530

185

200

225

235

405

345

80

155

315

Sugar, granulated

1,820

1,360

8.8
10.71

1,280
1,895

§4. Composition and Value of Food Materials Not Found in
the Dietary Lists. — In addition to the composition of articles
given in Atwater's tables should he mentioned that of other val-
uable foods. And we may look first at the familiar edible nuts
which are sometimes found upon the tables of the well-to-do, but
are generally regarded as a luxury suited to gratify the palate
but not well adapted to sustain the activities of body or brain.
The chemical composition of these nuts shows, however, that
they are exceedingly rich in substances needed for the proper nu-
trition of the entire organism. The following analyses of these
varieties of nuts which are easily obtained in our locality are
taken from Church r1

3Op. cit.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

87

Chemical composition of nuts.

Composition of Chestnut-Kernels

Water

Albuminoids, etc

Starch

Dextrin

Sugar

Oil

Cellulose

Mineral matter

Walnut Kernels:

Water

Albuminoids

Mucilage, etc

Oil

Cellulose

Mineral matter

Filbert-Kernels:

Water

Albuminoids

Oil

Mucilage, starch, etc

Cellulose

Mineral matter

Sweet Almonds (shelled):

Water

Albuminoids, etc

Oil

Mucilage, etc

Cellulose

Mineral matter

Pistachio-kernels:

Water

Albuminoids, etc

Oil

Mucilage, etc

Cellulose

Mineral matter

Cocoanut-kernels:

Water

Albuminoids, etc

Oil

Sugar, etc

Cellulose

Mineral matter

Ground or Pea Nuts (shelled):

Water

Albuminoids, etc

Starch, etc

Oil

Cellulose

Mineral matter

Parts in 100

In 1 pound.

14.0

S.5

29.9

22.9

17.5

1.3

3.3

2.6

Oz.

Gr.

44.5

12.5

8.9

31.6

0.8

1.7

7
2
1
5

0
0

53
u

185
24
56

119

48.0

8.4

28.5

11.1

2.5

1.5

7
1
4
1
0
0

297
151
245
340
175
105

6
25
54
9
3
3

0
4

8
1
0
0

420
0
280
192
210
210

7.4

22.7

51.1

13.0

2.5

3.3

1

3

8
2
0
0

80

277

77

35

175

231

46.7
5.5

35.9
8.1
2.9
1.0

7
0
5
1
0
0

200
385
325
130
203
70

7.5

24.5
11.7

50.0
4.5

1.8

1

3
1

8
0
0

87
403
382
0
315
126

Doubtless one reason why nuts do not constitute a more impor-
tant part of our dietaries is found in the fact that they are all
difficult of digestion by most people, while some of them, as the
peanut in the form in which we ordinarily obtain it, are quite
invulnerable to the attack of many stomachs. This objection
need not longer be urged, however, since methods of preparing

88

BULLETIN OP THE UNIVERSITY OP WISCONSIN.

nuts have become so perfected that products are now on the mar-
ket which will not trouble the most delicate digestive apparatus,
and which are at the same time highly nutritious. These prep-
arations present the nutritive elements in nuts in a variety of
forms, most of them resembling closely in general appearance
and consistency the products of milk. The terms given the dif-
ferent varieties indicate this, — nut butter, nut cream, and the
like. The composition of the nut foods manufactured at Battle
Creek, Ifich., are given below :

Proteids.

Fata.

Carbo-
hydrates.

Malted Nuts

23

26
24
19.6
0

20.4

52

52

24

20

49.3

Nut meal

19

Nut butter

19

39.4

Maltol

75

From an economical standpoint they probably furnish more
nutrition for money expended than meat and butter, as substi-
tutes for which in whole or in part they are especially well
adapted. They are highly esteemed by some hygienists, notably
by Kellogg, since, it is said, they furnish the necessary fat in
a better form than it can be obtained in butter, or any animal
fat which has become separated from the elements with which it
is ordinarily combined. It is maintained by these authorities
that butter cannot be assimilated in the condition in which it is
eaten, but has to be converted back into cream, that is emulsified,
before it can be utilized in the system. There is involved here
a general principle of nutrition which has been alluded to else-
where,— that elementary substances in the rure state cannot be
incorporated into the system, while they can without trouble
when organized in the natural way in plant or animal life.
But however this may be it is certain at any rate that the nut
products afford palatable and at the same time exceedingly nu-
tritious and readily assimilable articles of food; and they might
well have a prominent place in a student's dietary since it is of

O'SHEA ASPECTS OF MENTAL ECONOMY. 89

the greatest importance that he should, particularly in the morn-
ing meal, gain abundant nutrition in the readiest and most agree-
able way possible.

There are other food materials which should be mentioned in
this place before passing to consider the nutrient values of the
dietaries appearing in our statistical summary. These are, in
the first place, the preparations of grains wherein a certain pro-
portion of the carbohydrate ingredients have been removed and
all or most of the albuminous elements retained. Some of
them are known in the market as Granola, Granose, Malt Break-
fast Food, Ralston Breakfast Food, Purina, Health Flour, et al.
The composition of these foods shows that they contain a higher
percentage of proteid elements than the flours and breads pre-
sented in Atwater s tables.

Hoffman, chemist at the State Agricultural and Mechanical
College of South Carolina, has analyzed Purina Health Flour,
and found that it contained:

Water 1* 0 per cent.

Proteids 14 .9 per cent.

Carbohydrates 66 .2 per cent.

pat 1.6 per cent.

Fibre 1.6 per cent.

Mineral matter I-7 percent

An analysis of Malt Breakfast Food, made by the government
-chemists at Washington, under the direction of Prof. H. W.
Wiley, gives the following:

Proteids 11-63

Carbohydrates 77.00

Fats 175

Ash 105

Water. 7.85

Lignose and cellulose 73

Germos, as analyzed by the manufacturers, contains 20 per
cent, of albumen, 1.5 per cent, of fat, 62 per cent, of starch, and
1 per cent, of salts. Granola is said to contain a still higher
percentage of albumen, although I have not been able to secure
a<n analysis showing its exact composition. Granola and Malt
Breakfast Food are distinguished in another way, in that the
starch they contain is partially digested during the process of

90 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

manufacture by the application of heat in the first case and by
malting in the second, which convert it into certain varieties
of dextrin, a point which will be considered more fully later
in discussing the modes of preparing food. This predigestion
of the starch renders such foods much more palatable and de-
licious than the ordinary uncooked article. It may be remarked
here, too, that in view of the fact that the ease with which a
food can be made to yield the energy it contains is perhaps
the most important factor in the determination of its nutritive
value, at least for one engaged in mental labor, it can be seen
that the foods just mentioned are far superior to those generally
found in the dietary lists of our students.

§5. The Nutrient Value of Student's Dietaries, — Estimates
and Comments. — What now about the dietaries submitted in re-
sponse to our questionaire ? In order to determine their value
in a complete and scientific manner one should have ascertained
the precise quantity of each dish eaten, its exact composition,
and the digestive peculiarities of each individual ; and these data
could be obtained only with great difficulty, if indeed they could
be secured at all. But (and this has been said already) there
was at the outset no intention of making an elaborate and de-
tailed study of local conditions, so that the facts in hand are suffi-
cient to warrant the general suggestions which will be offered.
In estimating the value of a dietary one must know, in the first
place, how much energy a person could profitably expend in his
daily activities and what amount >and variety of food is neces-
sary to supply this. It has been calculated that a man engaged
in active muscular work expends energy equal to about 150,000
metre-kilograms or 4,000 calories, a calorie representing the
amount of heat required to raise one gram one degree Centi-
grade.1 While it has not been possible, so far as I know, to de-
termine the precise amount of energy expended by >a student en-
gaged in severe mental labor, yet one is warranted in assuming
that it is not far below that indicated for a man employed in
muscular pursuits,2 and it is not incredible that it should be
greater.

1 Stevenson & Murphy, Treatise on Hygiene, Vol. I, p. 401.

2 See, for instance, Sargent, North American Review, May, 1897.

O'SHEA — ASPECTS OP MENTAL ECONOMY. 91

To supply the energy required for all the needs of the organ-
ism during a day's activities, authorities agree substantially
upon the quantity of the various food materials necessary, al-
though the standards calculated for Germany and America are
somewhat different, the American being considerably higher,
probably due to the fact that our people are more active than the
Germans, and are constantly expending more energy, possibly a
good part of it going to waste. Atwwter1 gives the American
and European dietary standard as follows :

^Op. cit., p. 18.

92

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

American and European dietaries and dietary standards.

[Quantities per man per day.]

Dietaries.

American (.Massachusetts and Connecticut.}

Family of carpenter in Middletown, Conn

Family of glass-blowers in East Cambridge, Mass ..

Boarding house, Lowell, Mass. ; boarders, operatives
in cotton mills

Boarding bouse, Middleton, Conn., ( Food purchased
well-paid machinists, etc., at<
moderate work ( Food eaten

Blacksmiths, Lowell, at hard work

Brickmakers, Massachusetts; 237 persons at very-
severe work

Mechanics, etc., in Massachusetts and Connecticut;
average of 4 dietaries of mechanics at severe work

Average of 20 dietaries of wage-workers in Massa-
chusetts and Connecticut

Average of dietaries of profession- ( Food purchased
al men and college students in <
Middletown, Conn ( Food eaten

European (English, German, Danish, and
Swedish).

Well-fed tailors, England, Play fair

Hard- worked weavers, England, Playfair

Blacksmiths at active labor, England, Playfair

Mechanic, Munich, 60 years old, in comfortable cir-
cumstances, light work, Forster

Well-paid mechanics, Munich, Voiart

Carpenters, coopers, locksmiths, Bavaria; average
of 11 dietaries, Voit

Miners at severe work, Prussia, Steinheil

Brickmakers (Italians), Munich, diet mainly maize
meal and cheese, severe work, Ranke

German army ration, peace footing ,

German army ordinary ration, war footmg

Germanarmy extraordinary ration, in war

University professor, Munich ; very little exercise
Ranke

Lawyer, Munich, Forster

Physician, Munich, Forster

Physician. Copenhagen, Jurgensen

Average of 7 dietaries of professional men and stu
dents, Germany, Denmark, and Sweden

Nutrients.

Dietary Standards.

Adult in full health, Playfair

Active laborers, Playfair

Man at moderate work, Moleschott

Man at moderate work, Voit

Man at hard work, Voit

Man with little physical exercise. Atwater.. .

Man with light muscular work, Atwater

Man with moderate muscular work, Atwater.
Man with active muscular work, Atwater. .. .
Man with hard muscular work, Atwater

Pro-
tein.

Lbs.

.25

0.23

.29

.28

.23
.44

.40

.48

.34
.30

.27

.29
.34
.39

.26
.34

.27
.30

.37
.25
.30
.42

.22

.18
.28
.30

.25

.26
.34
.29
.26
.32
.20
29
!28
.33
.39

Fats

Lbs.

.28
0.29

.44
.41

.34

.67

.81

.65

.50
.36

.34

.09
.09
.16

.15
.12

.08
.25

.26
09
.13
.10

.22
.28
.20
.31

.22

.11
.16

.09
.12
.22
.20
.22
.28
.33
.55

Car-
bohy-
drates.

Lbs.

.76
1.06

1.21
.94

.81
1.75

2.54

1.65

1.38
1.12

1.08

1.16
1.37
1.47

.76
1.06

1.28
1.40

1.49
1.06
1.08
1.49

.53
.49
.80
.53

.63

1.17

1.25

1.21

1.10

.99

.66

.77

.99

1.10

1.43

Fuel
values.

Cat.

3,055
3,590

4,650
4,010

3,490
6,905

8,850

6,705

5,275
4,140

3,925

3,055
3,570
4,115

2,525
3,085

3,150
4,195

4,540
2,800
3,095
3,985

2,325
2,400
2,830
2,835

2,670

3,140
3.6.4)
3,160
3,055
3,370
2,450
2,800
3,520
4,060
5,700

Nutri-
tive
ratio.*

5.5

8.2

7.6

6.8

7.3

7.4

11

6.6

7.5
6.6

6.6

4.7
4.8
4.7

4.3
4

5.3

6.7

5.3
5

4.7
6.3
4.4
4.1

4.7

5.5
4.7
4.9
5.3
4.7
5.5
5.7
5.8
5.6
6.9

* The nutritive ratio is the ratio of the protein to the sum of all the other nutritive in-
gredients. The fuel value of the fat is two and a quarter times that of the protein and
carbohydrates. In calculating the nutritive ratio the quantity of fats is multiplied by
two and one-fourth. This product is added to the weight of the carbohydrates. The
sum divided by the weight of the protein gives the nutritive ratio. Materials with

O'SHEA — ASPECTS OF MENTAL ECONOMY. 93

It is probable that these standards should be somewhat modi-
fied for persons engaged in intellectual pursuits, greater em-
phasis being laid upon the albuminoids and fats, and less upon
the carbohydrates ; or, what is perhaps a juster way to put it, the
proportion of carbohydrates should be somewhat less in the di-
etary of a student than that appearing in any of the tables given.
This inference is based upon a point discussed in preceding par-
agraphs, wherein it was said that the nutrition of nerve cells is
believed to demand albuminoids and fats in largest ratio.

Taking now any one of the individual dietaries already given,
say Xo. 1526, it will be possible to estimate with a fair degree
of accuracy its worth judged by the standards here presented.
Of course, considering that the exact amount of food eaten has
not been indicated makes it impossible to determine the value
only in a general or inferential manner. Assuming, however,
that the quantity of each article consumed would be approxi-
mately the same for students and other adults wTe may gain some
impression of the value of our dietary by comparing it with
others when the articles are substantially the same, and where
the amounts of each eaten have been accurately obtained and the
nutritive value calculated. Such a study has been made in
Boston under the direction of Atkinson,1 and his results are in-
dicated below :

large amounts of fats or carbohydrates and little protein, like fat meats or potatoes,
have a "wide" nutritive ratio. Those with a large amount of protein as compared with
the carbohydrates and fats, like lean meat, codfish, and beans, have a "narrow" nutri-
tive ratio. In other words, the materials rich in tissue forming substances have a nar-
row, and those with a large preponderance of fuel materials have a wide, nutritive ratio.
This is an important matter in the adjusting of food to the demands of the body.

A well-balanced diet is one which has the right ratio of protein to the fats and carbo-
hydrates. A relative excess of the tissue formers makes the ratio narrow, while an ex-
cess of the fuel ingredients makes an overwide ratio in the diet. Either of these errors
is disadvantageous. Our food materials and our diet are apt to have too wide a nutri-
tive ratio. In other words, we consume on the whole relatively too little protein and
too much of the carbohydrates and fats.
*Op. cit., p. 150.

94

BULLETIN OF THE UNIVERSITY OP WISCONSIN.

Sunday, February 22, 1890.

BREAKFAST.

Milk

Flour griddle cakes

Syrup

Butter

Cheese

Cream ,

Coffee

Sugar

Oatmeal

Water

Man.

36H

Woman.

Ounces.

Ounces.

4

6

2*4

4

*

Y%

fc

a

y*

V4

3

%

10

8

y*

Taste.

11V4

5

4

0

24K

DINNER.

3

y*

5l/2+
Wi + 154 oz. waste

2

1
3V4 + Yi oz. waste

1

0
18

Wt

Fat beef

0

Vegetables, parsnip, beet, turnip

5

954 + 2,Vt oz. waste

0

w%

Fruit

4 + V4 oz. waste

Water

12

79%

5854

SUPPER.

5 + 1 oz. sugar.
US
% + % oz. sugar.
H.

1
0
6

5 + 1 oz. sugar.

1%

0

a

0

12

Milk

0

99%
5

71V4

5

94%

66/*

O'SHEA — ASPECTS OP MENTAL ECONOMY.

95

Calculation of the above :

MAN.

Milk

Cream

Butter

Cheese

Bread

Beef

Sugar

Potato

Vegetables

Fat in beef

Griddle cakes .

Oatmeal

Cookies

Nuts

Fruit

Crackers

Calories 2,38t.

Grms.
albumeu.

4.5
2.5

0.4
2.1
6 4

28.6

39
2

Fats.

10.5
11.2

4.5
14
2.0

SO. 00

3 9
10.1

32.9
2.2
0 5
6.3

Sugar.

4.5

2.5

14

i'.t

15
1.5
0.1

92.1

54

15.4

17

Starch.

41 4

41.2

35.0

50.8

9.7

15.8

297.3

Grms.
Total.

112

84

38
7

91

84

56
196
154

14

70
322 (80 dry)

18

28
196

28

1,498

WOMAN'.

Milk

Cream

Butter

Cheese

Bread

Beef

Sugar ,

Potato

Vegetables ...

Fat beef

Griddle cakes
Oatmeal .....

Nuts

Fruit

Calories 1,359.

Grms.
Albumeu.

Fats

13.4

0.4
0.6
2.1
3.4
14.3

3.9

1.8

16.8
4.9
1.1

11.3
1.7

48.4
2.2
0.3
3.2

2.5
3.7

62.7

73.8

Sugar.

Starch.

13.4
0.4

33.8

u"

27.7

41.2

56.0
22.2

18.3

227.0

Grms.
Total.

336

14

56

7

49

42

35

196

140

0

112

140 (35 dry)

7

210

1,344

Since the dietary standard given by Atwater calls for at least
125 grams of albumen, 125 grams of fat, and 450 grams of carbo-
hydrates1 it can be seen that Atkinson's man and woman did
not consume enough of nutritious food. While these dietaries
are deficient in all the food elements, the deficiency would be
especially marked in respect of protein and fats if the
guests were students. It is probable that the same thing can be
said of dietary No. 1526. If the person living on this bill of

iLoc. cit.

96 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

fare should consume enough of the articles mentioned to supply
the requisite amount of albuminous nutrients he would probably
overload the organism with carbohydrates and waste matters;
although this can be said not as founded upon direct and con-
clusive, but only upon indirect and inferential, evidence. It
is suggestive to note in this connection that many authorities1
have advanced the opinion that American dietaries as a rule ac-
cord too prominent a place to carbonaceous foods, and if this
be true of our people at large, it must be especially true of the
food of students. The predominance in the dietary lists of our
students of such carbonaceous foods (and they are regarded as
carbonaceous since the ratio of carbohydrates to protein is
greater than that required for perfect nutrition) as white bread,
potatoes, griddle cakes, cabbage, beets, and the like, indicates
that they are too highly esteemed, relatively speaking, in our
own locality, as they are elsewhere.

Kellogg maintains that the proportion of albumen to carbohy-
drates in a model bill of fare should be as 1 to 7, while Atwater
demands that the ration be much richer in protein, the desired
proportion being, in his opinion, about as 1 to 3 or 4. Other
estimates lie somewhere between these extremes,2 the weight of
testimony, however, seeming to declare that Atwater's formula
would give too "narrow" a ration, and that the albuminoids
should not constitute more than 1-6 or 1-7 of the quantity of the
other foods. !Now, the composition of the ordinary food ma-
terials shows that few of them contain an excessive amount of
protein, wThile the bulk of them are deficient in this respect, as
will appear from the following table:

JFor instance, Jordan, op. cit., p. 57; Atwater, op. cit., p. 18.

2 For a good discussion of the question, see Stevenson & Murphy, loc. cit.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

97

Proportion of nitrogenous to carbonaceous elements in various foods.

Album,
or

Nitrog.

Carbona-
ceous.

Album.

or
Nitrog.

Carbona-
ceous.

Lean beef

1
1
1
1

1
1
1

1

1

.5
1.9
2.7
2 7
2.4
3.6
5.0
6.1

7.0

1
1
1

1

1
1

1

7.7

Eggs

9.3

Peas. .

10.7

Beans

Carrots, and other veg-
etables (averaging)..

Barley meal

Lentils

11.0

12.7

Milk

13.0

Fat beef

Common fruits (aver-

Oatmeal

80.0

Whole wheat meal or
bread

The quantities of some of the familiar foods which must be
consumed daily in order that the required amount of protein
may be obtained are shown below. The table gives warrant for
the assertion that one whose dietary consists almost wholly of
fruits, vegetables, white bread, tea and coffee can hope to gain
but little more than enough nutrition to keep body and soul to-
gether.

Amounts of various foods necessary to furnish the proper daily
amount of albuminous elements.

Lean meat

Eggs

Peas

Oatmeal

Baker's bread

Wheat flour (fine)

Graham flour

Indian meal

Rye meal

Rice

Potatoes.
Grapes...

Ounces.

15.6

21.2

11.2

23.6

36.7

27.5

25.5

26.3

37.1

Poimds.

3.0

8.8

247|

Apples . . .
Peaches .
Plums .. .
Cherries .
Carrots .
Turnips. .
Cabbage.
Parsnips.

Milk
Beer

Pounds.

99!4

50.0

991/*

22.0

15.0

16.0

22.0

18.0
Pints.

4.5
185.0

Tea— Over 2lA lbs. dried leaves or 192 pints
of strong infusion.

Coffee— About 3 lbs. of dried berries.

98 BULLETIN OF THE UNIVER6ITT OP WISCONSIN.

The too great proportion of carbohydrates and waste materials
in some of our students' bills of fare could be balanced in a
pleasing and economical manner by using more largely the pulse
foods, as beans, peas and lentils ; nut products, as nuttose, malted
nuts, and protose ; and substituting, at least in part, whole wheat
bread made from such flour as the Purina Health Flour for the
variety found so exclusively upon the tables in our community.
And it should be pointed out especially that whole wheat bread
and graham bread are not the same article, either in respect of
nutritive value or readiness and ease of digestion. The graham
bread with which we are all familiar contains the outer husk
of the wheat kernel, which cannot be assimilated, and which
seems to accomplish little else than to irritate the digestive tract.
Whole wheat flour, on the other hand, possesses the great ad-
vantage of having the fibrous covering removed while preserving
all of the albuminous part of the kernel. In the ordinary white
bread, however, a large fraction of the albuminous part of the
wheat is removed in milling. Church discusses this point so
satisfactorily that I may quote his words i1

"There are two parts of the wheat grain which, in various milling
processes, are often removed. One of these is the germ, the other is
the outermost coat of the grain. The germ is removed in roller-milling,
because its presence tends to discolor the flour, and gives it a marked
tendency, especially when kept under unfavorable conditions, to acquire
a rancid taste and odor. That the exclusion of the germ is to be re-
gretted on dietetic grounds is evident when its singular richness in
oil, in nitrogenous matters, and in phosphoric acid, is considered. The
following analysis was made on a pure sample of flattened germs from
a roller-mill: —

In 100 parts.

Water ■ 12-5

Albuminoids, diastase, etc 35.7

Starch, with some dextrin and maltose 31 .2

Fat or oil 131

Cellulose 1-8

Mineral matter 5.7

More than half this mineral matter was phosphoric acid; indeed, it
amounted to no less than 60.6 per cent, of the total ash, so that the
original embryos contained nearly 3*4 parts per hundred of this valua-

JOp. cit., p. 70.

O'SHEA ASPECTS OF MENTAL ECONOMY. 99

ble constituent of bone. The nitrogenous matters amounted to thrice
the proportion present in the whole wheat grain; the oil or fat was
more than six times as much. It should be added that the albuminoid
matter included little or no tenacious gluten, but a considerable quan-
tity of the diastatic ferment.

"But if, on some grounds, the exclusion of the germ from our mill-
products is a procedure of doubtful utility, there can be no question
that the removal of the fibrous outer envelope of the grain is of con-
siderable advantage. The following figures were obtained in the analy-
sis of a carefully prepared sample: —

In 100 parts.

Water 15.2

Albuminoids (from total nitrogen) 10.4

Oil 2.5

Ash or mineral matter 2.6

To these analytical results it may be added that this ash contained
no more than 15.3 per cent, of phosphoric acid. All these results, and
the high proportion of fiber present, contrast very strongly with those
previously given in the analysis of the germ."

If now one desired to work out bis daily dietary so as to
obtain the right proportions of albuminous and carbonaceous
elements with something like mathematical accuracy, which
process, if it demanded bis constant attention and made him
over-conscious of his food, would certainly be an unwise pro-
ceeding;— but if be wished to do it, be might proceed accord-
ing to the following scheme (Kellogg) :

Combine 8 ounces leaD beef with 4 pounds 8 ounces potatoes.

Combine ~ilA ounces lean beef with 1 pound 8 ounces rice.

Combine V-A ounce lean beef with 1 pound 8 ounces Indian meal.

Combine 12 eggs with 1 pound 6 ounces rice.

Combine 9 eggs with 5 pounds 2 ounces potatoes.

Combine 3 pints of milk with 1 pound of rice.

Combine VA pints of milk with 4 pounds 4 ounces potatoes.

Combine 7 lA ounces peas with 1 pound 4 ounces rice.

Combine 6 ounces peas with 5 pounds of potatoes.

Combine 5 ounces oatmeal with 5 ounces rice.

Combine 4 ounces oatmeal with 1 pound 11 ounces potatoes.

Combine 4 ounces oatmeal with 5 ounces rye meal.

Combine 15 ounces oatmeal with 10 ounces Indian meal.

A word should be said of the heat-producing properties of
foods, since the extremes of climate in these regions make this
a very important matter. Yet it is almost entirely disregarded

100 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

by the makers of bills of fare in our midst. Fats have as prom-
inent a place on our tables in mid-summer as in mid-winter;
there seems to be a sort of stereotyped form that is used all
the year round. But the organism loaded with calorifacient
foods in our hottest weather is obviously at a great disadvan-
tage; just as is one deprived of a liberal allowance of them in
January or February. Landlords should know something of
the calorific qualities of different articles, such information,
for instance, as that presented in the accompanying chart, and
they should take into account the standing of the thermometer
when constructing a bill of fare.

So much has been said regarding the evil of making carbo-
hydrates too prominent in one's dietary that a word is demanded
respecting the tendency in some cases of consuming more albu-
men in the daily ration than the organism can utilize. This
is liable to be the case where one eats heartily of lean meat
three times a day, while at the same time not reducing the
amount of other substances rich in protein. Suppose that one
eats five ounces of lean beef at each of three meals, he will ob-
tain 4.45 ounces of protein, the maximum amount for a man
engaged in active labor, mental or physical. Then if he add
bread, peas, milk, puddings, and nuts, he will convey into his
system a considerable quantity of albumen that will have to be
eliminated unused ; and it seems reasonable to suppose that the
working capacity of the organism will be in so far reduced.
Overeating in this way must be regarded as lessening the effi-
ciency of the organism in somewhat as serious, a sense perhaps
as undereating.

An examination of dietary 'No. HOI shows that meat was
eaten three times every day for a week, and to this were added
each day a cereal rich in albumen, besides bread, milk, corn,
eggs, and other articles. I^ow, if this guest ate heartily of meat
at each meal, it is practically certain that he consumed more pro-
tein than he could utilize, and it must consequently have been a
hindrance rather than a help to him. Everyone is doubtless
familiar with the opinions of physicians to the effect that sed-

chart showing calorics in tin nutrients in one pound of each food

material.

(At water.)

Beef) round, ratlin- lean — ""'

Beef, neck 1,108

Beef, sirloin, rather fat 1, 173

Beef, Hank, very fat 2,750

Beef, Bide, well fattened — 1,463

Mutton, leg 1.142

Mutton, shoulder 1,281

Mutton, loin (chops) 1.755

Mutton, Bides, well fattened 1,906

Smoked ham 1,960

Pork, very fat 3,462

Flounder 286

Cod 310

Haddock 331

Blueflsh 104

Mackerel, rather lean 430

Mackerel, very fat 1,026

Mackerel, average 696

Shad 750

Salmon 967

Salt cod 416

Salt mackerel 1,364

Smoked herring 1,343

Canned salmon 1,036

Oysters 229

Hen'seggs 760

Cow's milk 338

Cow's milk, skimmed 176

Cheese, whole milk 2,044

Cheese, skimmed milk 1, 166

Butter 3,691

Oleomargarine 3, 679

Wheat flour 1, 655

Wheat bread 1,278

Rye flour 1,614

Beans 1,519

Peas 1,476

Oatmeal 1 , 830

Corn (maize) meal 1 , 616

Rice 1,627

Sugar 1,798

Potatoes 427

Sweet potatoes 416

Turnips 139

O'SHEA — ASPECTS OP MENTAL ECONOMY. 101

entary people especially should eat sparingly of meat if they
are generous in their daily allowance of other protein-bearing
foods,1 since elimination is a relatively serious matter for those
who are not active muscularly much of the time. Many be-
lieve, and it seems with a show of reason, that sedentary peo-
ple should get their albuminous foods in some other substances,
for the most part, than meat, since all flesh contains worn out
products that have not been eliminated in the life of the ani-
mal, and that are not only valueless for the purposes of nutri-
tion, but are moreover a sort of drug in the system. A stu-
dent eating a large amount of beefsteak, for instance, from
which the blood has not been thoroughly drawn, and not exer-
cising a great deal, cannot but be handicapped in mind and
body, since his organism must become clogged up with the toxic
products of his own activities and of those of the animal which
he imports into his system.

§3. Specimen Dietaries Fulfilling the Requirements of Ade-
quate Nutrition. — In view of what has been presented in pre-
ceding sections it may be instructive now to show in actual bills
of fare how the principles which have been advanced can be
embodied in practice. Atwater, Atkinson, Kellogg, and others
have constructed dietaries indicating the required daily amount
of each article of food which in the total will give the right
quantity of the several nutrient elements. The food materials
used in these dietaries are substantially such as constitute the
body of the bills of fare of our students; and while some of
these could with great advantage be banished from our tables
and other articles substituted in their stead (for instance, nut
foods taking the place of pork in every form, and much of the
other flesh, cream being used more largely in the place of but-
ter, the nitrogenous cereals discussed in §4 being added to the
lists, etc.), yet it will be well to see what can be done with
those things, valueless as some of them are, that tradition keeps

JSee The North American Review, Vol. 164, p. 664, for expert opinion upon
this subject.

102

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

in the diet lists of students as of other people. In the case
of Atwater's tables the cost is given, and this will be referred
to later.

Daily dietaries — Food materials furnishing approximately the 0.28
pound protein and 3,500 calories of energy of the standard for
daily dietary of a man at moderate muscular work.

Amount.

Cost.

Nutrients.

Fuel
value.

Food materials.

Total.

Protein.

Fats.

Carbohy-
drates.

Beef, round steak.

Ounces.
13

3

6
22

Cents.

11.40

5.65

1.25

5.50

Pounds.
.26
.16
.17

.89

Pounds.
.14

.02
.12

Pounds.
.12
.16

Pounds.

Calories.
695

Butter

680

Potatoes

.15

.75

320

.02

1,760

44

23.80

1.48

.28

.30

.90

3,455

Pork, salt

4

2
16

8

3

3.75
5
2

.21
.11

.84
.33

.21
.11

.02
.01

.35

880

Butter

450

.23
.04

.59
.28

1,615

640

30

13.75

1.49

.27

.87

3,585

12
3
28
12
12

15

5.65

6.15

.95

1.85

.25
.16
.22
.12
.65

.12

.13
.16

.08

725

Butter .

680

Milk, Ui pints

.05
.01
.08

.08
.11
.56

570

240

Flour

.01

1,235

67

29.60

1.40

.27

.38

.75

3, 450

Beef, neck

10
1

16

16
4

16
3

4.40
1.90
3.^0
1.25
1.25
4
.95

.19
.05
.13
.17
.23
.67
.19

.10

.09
.05
.04

550

Butter . ..

225

Milk, 1 pint

Potatoes

.04
.02
.04
.09

.05
.15
.17
.56
.19

325
320

Oatmeal

.02
.02

460

Bread

1,280

Sugar

345

66

17.25

1.63

.29

.22

1.12

3,505

Beef, shoulder

8
4
VA

24

8

'I
10

3

6

3.75

4.70

5.25

.65

.65

1.55

.95

.16
.10
.13
.18
.09
.11
.55
.19

.09
.05

.07
.05
.13

.06

450

Salmon, canned

245

Butter ....

565

.05
.01
.02
.07

.07
.OS
.08
.47
.19

485
160

Oatmeal

Flour

.01
.01

230

1,030

345

61*4

23.50

1.51

.29

.33

.89

3,510

Beef, sirloin steak

8
5
2

24
8
3

12
2

10

6.25

3.75

5.25

.65

.95

3

.65

.17
.14
.11

.18
.09
.17
.50
.12

.08
.C4

.09
.10
.11
.06

485

Mutton chops
Butter . ..

465

450

Milk, llA pints

.05
.01
.03
.07

.07
.08
.13
.42
.12

485
160

Bread

Sugar

.01
.01

345
965
230

64

50.50

1.48

.28

.38

.82

3,5,85

O'SHEA — ASPECTS OF MENTAL ECONOMY.

103

Daily dietaries — Food materials furnishing approximately the 0.28
pound of protein and 3,500 calories of energy, etc.— Continued.

Food materials.

Amount.

Cost.

Nutrients.

Total.

Protein.

Fats.

Carbohy-
drates.

Fuel
value.

Boef, round steak

Cod, dried

1 egg

Butter

Milk, 1*4 pints

Potatoes

Oatmeal

Flour

Sugar

Beef, shoulder

Ham

One egg

Butter

Milk, H pint

Potatoes (white).
Sweet potatoes . . .

Corn meal

Bread

Sugar

Ham

Cod, dried

Three eggs

Butter

Cheese

Milk, 1 pint

Potatoes (white) .
Sweet potatoes...

Corn meal

Bread

Sugar

Ounces.

8

2

VA

3
20

8

2
10

4

Cents.
7

.90
2 00
5.65
4.40
.65
.65
1.55
1.25

Pounrls.
.16
.03
.02
.16
.15
.09
.12
.55
.25

Poumls.
.09
.03
.01

Pounds.
.07

Pounds.

.01
.16
.05

.04
.01
.02
.07

.05
.08
.09
.47
.25

.01
.01

58/,

24.05

1.53

.27

.31

.95

9
6

m

VA

8
8
8
8
4
2

6.75
6
2

2.80 I
1.85

.75
1

1.25
1

.65

23.85

.18

.19
.02
.OS
.06
.09
.12
.42
.16
.12

.10
.06
.01

.08
.13
.01
.08
.02

.02
.01
.01

.05
.02

.02
.08
.11
.35
.14
.12

.02

56

1.44

.28

.34

.82

8
4

VA
VA
1

16
6
8
8
4
2

8

1.75

6

2.80

1

3.50

.50
1

2.50
1

.65

.24
.02
.07
.08
.0+
.13
.07
.12
.42
.16
.12

.07
.02
.04

.17

.03
.03
.02
.04

.02
.04
.01
.01
.05
02

.05
.08
.11
.35
.14
.12

.02

63

28.70

1.47

.28

.36

.83

Calories.

425

40

70

680

405

160

230

1,030

460

3,500

515
655

70
340
165
160
210
825
320
230

3,490

~~ 870~
50
200
340
130
325
120
210
825
320
230

3,620

Kellogg1 has determined the nutritive values of different por-
tions of the common articles of diet, as well as some that are
not so well known, and his results are of much practical inter-
est. By means of the tables 'here given one could make com-
binations of foods with something like precision and definite-
ness.

^Balanced Bills of Fare — Good Health Pub. Co., Battle Creek, Mich.

104

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Nutritive value of foods.

Food.

Bananas

Oranges

Lemons

Berries, Btewed. .

Dates

Prunes, stewed..
Raisins, stewed..

Apple sauce

Peaches, canned.
Fruit-juice.... ...

Sauce for grains.
Apples, fresh —

Grapes, fresh . .
Peaches, fresh.

Apricot, canned

Grape pulp

Blackberry, canned ...

Cherry, canned.

Pear, canned

Strawberry, canned .. .
Whortleberry, canned.

Melon

Plum

Fig.

Tomato

Apple, baked

Rice, steamed

Oatmeal

Crystal wheat

Gluten mush

Graham mush

Wheatose

Rice with nuttose

Macaroni ,

Granola

Granose

Zwieback

Graham crackers

W. W. wafers

Beaten biscuit

Sticks

Rolls

Passover bread

Graham bread

W. W. bread

W. bread

Nut-gravy toast

Prune toast

Berry toast

Cream toast

Nuttose roast

Nuttose and tomato.

Potato, mashed

Vegetables, fresh —

Tomato, stewed

Potato, baked

Nut gravy

Soup

Sugar

Beans, boiled

Weight
Oz.

Measure.

Pee Cent, of

Pro-
teids.

Carbo-

Fats. hy-
drates

Calo-
ries in
1 oz.

2.
2.

2.5
9 8
2.
9.2
9.2
9.5
9.2
8.8
8.5
13.

5.
3.

S.5

9.2
9.2
9.2
9.2
9.2

1 peeled ....
1 peeled

1 peeled ....
.5 pint

7

.5 pint

.5 pint

.5 pint

.5 pint

.5 pint

.5 pint

2 large or 4
small

1 av. bunch. ..
1 peeled and

pitted

.5 pint

.5 pint.
.5 pint.
.5 pint.
.5 pint.
.5 pint.

8.

5.5

5.75

7.

8.25

7.

7.

6.

6.5

4.25

2.75

2.2

3.

2.5

2.25

2.

4.

3.75

1.

1.

1.

6.

6.

6.

6.

6.

8.75

7.75

8.

8.

4.

9.

8.5

7.

S.75

1 medium .

1 large

.5 pint

.5 pint. .. .
.5 pint. .. .
.5 pint. .. .
.5 pint. .. .

.5 pint

.5 pint. .. .

. 5 pint

.5 pint... .

4

2 pieces . . .

6

6

6

12

6

12

1 piece

1 piece

1 piece

1 piece . . . .

1 piece

1 i iece

1 piece

.5 pint. ..

.5 pint

.5 pint. ..
.5 pint. ..
.5 pint. ..
1 medium
.5 pint...
.5 pint. ..
.5 pint. ..
.5 pint. ..

1.4
1.31
1.
1.4

.9
.5

1.8
.18
.7
.7

.7

.4

.6

.7

.5

2.

.5

.7

.4

1.1

.8

1.

.4
4.
1.6
.18
3.
6.4
5.7
12.
6.8
5.7
4.2
10.
15.
15.4
13.6
9.8
9.8
11.7
11.7
11.7
11.7
9.5
9.8
8.8
6.8
6.8
6.8
6.8
4.3
4.3
3.2
1.6

1.4

3.2

1.9

.24

.74
.7

.2

.5
.3*

.3

.24

.16

3.9

3.
.6
.9

1.3
2.
3.
2.3
2.

13.6
13.6
1.2
1.2
1.2
1.2
1.4
1.4
1.7
1.
1.
1.
1.
1
1

.9
9
.15
.3
.15
.15

29.8
11.

8.3
12.4
58.
14.7
23.6

9.4
12.5

9.2

9.8

12.

16.3

12.5

11.

21.

5.5
12.
11.5

6.8

5.9

2.2

8.2
49.8

2.5

9.4
31.4
29.7
29.5
22
3*'.8
29.5
32.1
75.
75.
79.1
70.
70.
70.
80.
80.
80.
80.
53.3

50.7

56.3

35.

35.

35.

35.

12.5

12.5

27.5
4.
1.25

27.5

39
14
14
16
67
IT
34
12
15
13
13

14
1»

15
13

32
7
15
14
9
8
5

10
62
12
5
40
53
49
44
52
44
46
104
114
117
104
128
128
110
110
110
110
80
75
81
52
52
52
52
25
25
36
8
3

1.

97.8

3
111

O SHEA — ASPECTS OF MENTAL ECONOMY.

105

Nutritive value of foods— continued.

Food.

Cream

Milk

Egg

Sterilized butter.. .

Kumyss

Cottage cheese

Malted nuts

Almond cream

Nut butter

Bromose

Maltol

Nuttose

Nuttolene

Nut meal

Stewed nuttolene
Beefsteak

Weight
Oz.

Measure.

8.5
8.5
1.5

8.5

.5 pint
.5 pint

.5 pint

8.75

1.

9.

3.

3.

3.75

9.

.5 pint

2 cakes.

.5 pint

.5 pint
.5 pint

Per Cent, of

Pro-
teids.

2.7
3.6

14.
1.
3.7
3.6

23.
2.7

16.4

19.6

30.
30.
28.3

Fats.

19.3

26.7
4.

10.5

85.
3.6
3 7

20 '.4

26.7

26.4

24.

20.

30.

30.

46.2

Carbo-
hy-
drates.

2.8
4.7

4.7

6.
49.3

2.8

9.5
39.4
75.
18.
18.

1.8

Calo-
ries in
1 oz.

3.6

.ii

75

21

47

218

20

20

140

75

101

135

136

139

139

161

37

Constructing bills of fare from these tables we could make
combinations like the following, which, according to Kellogg,
are each equal to one-half of a ration, while Atwater and oth-
ers would estimate them at one-third of a ration. Kellogg
would advise only two meals a day, each affording the amount
of food indicated in the combinations given ; while Atwater
would counsel three meals a day.

106

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Combination bills of fare.

Foods.

Weight
Oz.

Measure.

Calories or food
units.

7

6

6

l1/*

7

30

Vi pound . . .
1-6 pint

M pint

Proteids... 845

Fats 175

Bread, whit©

Carbohydr. 825

Beans

Bananas

3

_

Total.... 1,445

Eggs

3
5

8
2

2

Proteids... 197

Yz pint

Fats 526

Carbohydr. 590

Butter

Total.... 1,313

18

Bread, white

10
8
5

23

10 slices

Vt pint

Proteids... 199

Milk

Fats 458

'.Carbohydr. 633

Total.... 1,290

13

7

20

5& pint

Proteids ... 296

Malted nuts

Fats 4S4

Carbohydr. 461
Total.... 1,241

Passover bread

4
4
9
2

19

13 pieces

M pint

1

Proteids... 200

Macaroni

Fats 162

Tomato

Carbohydr. 818

Bromose

Total.... 1,180

Beefsteak

8

10

8

26

V4 pound . . .

% pint

8 slices

Proteids ... 364

Fats 113

Bread, white

Carbohydr. 823

Total.... 1,300

String beans

8
16
12

7
7

w

51 V,

lA pint

2 large

M pint

V4 pint

7 slices

Proteids ... 205

Fats 409

Soup

Carbohydr. 619

Nuttose roast

Graham bread

Sterilized butter

Total.... 1,323

O'SHEA — ASPECTS OF MENTAL ECONOMY. 107

CHAPTER IV.

RELATIVE VALUE OF FOODS IN THE PRODUCTION OF NERVOUS

ENERGY (C0nt).

§1. Condiments as Force Producers. — A word should be said
regarding those articles often designated as food adjuncts or
food accessories, or more familiarly, condiments. These in-
clude the spices, peppers, pickles, vinegars, and all the things
designed to whet the appetite, as we say. No one maintains
that they possess any nutritive value, but many believe they are
essential to the excitation of the digestive juices, and hence
are of much worth in one's dietary. Authorities seem to agree
that when food is unpalatable some of these artificial excitants
may be of service; but this does not imply that the materials
most nutritious and wholesome do not possess in themselves
flavors which may be developed by proper cooking and which
will be sufficiently stimulating to secure a generous flow of di-
gestive juices. It deserves more than passing notice that young
children cannot be induced to take food adulterated, so to speak,
with these foreign substances ; and it seems to be only when
the digestive processes become deranged from abnormal and in-
jurious practices that unnatural stimulants must be employed.
Grant Allen1 has pointed out that whiskey, pepper, and the
like are usually found together in one's diet ; organs thus over-
stimulated crave a continual increase in stimuli until it hap-
pens that one can enjoy no food in its natural flavors, and must
add pepper, vinegar and whiskey to everything he eats in or-
der that he may endure it at all.

On the tables in our own locality vinegar is the acid condi-
ment most universally employed, alike in its pure state, and
obscured in pickles, preserves, and similar "relishes." It is, of

1 Popular Science Monthly, Vol. '26, p. 468.

108 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

course, generally known that vinegar is the result of decompo-
sition of natural fruit juices which contain the various acids,
as malic, citric, etc., needed by the system to promote right
digestive and eliminative processes. Vinegar, that is to say,
is not found in ripened fruits before decomposition takes
place. Xow it is doubtless a principle of universal application
in nutrition that foods are best appropriated when they are
gained in their native forms, so to speak, as found in ripened
fruits and grains or in animal flesh. It is to be regretted
that apples and other fruits do not occupy a more prominent
place in our dietary lists, when there would be less need of
"pickles." The more general use of unfermented fruit juices
served as sauces, for instance, is also greatly to be desired in
our midst.

§2. The Influence of Tea, Coffee and Cocoa Upon the Pro-
duction and Expenditure of Force in the Organism. — From the
point of view w^hich is being taken in this bulletin in the dis-
cussion of nutrition, the most important food accessories are
those which have a marked effect upon the central nervous sys-
tem, as tea, coffee, cocoa, and the various forms of alcoholic
"drinks," — wine, beer, whiskey, and the like. It has long been
held that a cup of tea or of coffee cheers but does not inebri-
ate; and it has come to be generally felt that tea and coffee
are necessary adjuncts to one's diet. ^Nearly every student
enjoys his cup or cups of tea or coffee at every meal and many
apparently believe they derive real nutrition from these bever-
ages. The analyses1 of tea, coffee, and cocoa which follow show,,
though, that while they possess a modicum of nutrients, yet one
gets such a small allowance of these in the quantity of tea or
coffee which can be imbibed at any meal that their nutritive
value is practically zero.

Church.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

109

Analyses of tea, coffee, and cocoa.

Composition of black tea :
Water

Albuminoids
Theine
Tannin

Chlorophyll and resin
Essential oil
Minor extractives
Cellulose, etc
Mineral matter

Composition of roasted coffee
Water

Albuminoids
Theine (Caffeine.)
Fat or oil
Tannin

Minor extractives
Cellulose, etc
Mineral matter

Composition of cocoa :
Water
Albuminoids

Fat

Theobromine

Cacao-red

Tannin

Gum, etc

Cellulose and insoluble matter

Mineral matter

People do not commonly prize tea and coffee, however, for
their nutritive worth, but only for the stimulating effect which
they exert upon the nervous system. Smith1 has carefully
studied their action upon the vital functions and it will be well

And first regarding tea :

to give the results of his experiments

"1. As to the Carbonic Acid Evolved in Respiration.

"1. One hundred grains of the finest black tea gave a maximum
increase of 0.87 grain and 1.72 grain per minute in 50 and 71 minutes
on two persons.

"2. Fifty grains gave to four persons maxima of increase of 1.08,
1.38, 2.58, 1.6, 2.0, and 0.69 grains per minute, under different experi-
ments.

"3. One hundred grains of the finest green tea, drank when cold, gave
maxima of increase of 0.9, 2.58, and 0.64 grains per minute on three
persons.

"4. Twenty-five grains of green tea, drank when cold, and after hav-

!Op. cit., pp. 347-350.

110 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

ing been infused several hours, and repeated every quarter of an
hour, for five doses, gave an average increase of 1.2 and a maximum
Increase of 1.8 grain per minute. The total increase, as shown by ten
observations, was no less than 193 grains; and at the close of the
experiment the increase continued at the rate of 54 grains per hour.

"5. When 150 grains of black tea, infused in one pint of water, were
taken, and the whole carbonic acid was collected for 65 minutes, it
was shown that there had been an excess of 51.36 grains evolved,
which was not more than one-fourth of the total increase when the
tea had been divided into repeated doses.

"6. When we took 100 grains of black tea, and the whole carbonic
acid was collected during 1 hour and 50 minutes, the total increase
was 70.40 grains.

"2. As to the Volume of Air Inspired.

"There was an average increase in the quantity of air inspired in
every experiment but one. Thus pursuing the order of the above
mentioned experiments,
In No. 1, the quantity was increased by 71 and 68 cubic inches per

minute.
In No. 2, the increase was 34, 29, 50, 72, 95, and 26 cubic inches per

minute.
In No. 3, the average increase was 120 and 50 cubic inches.
In No. 4, the average increase was 66 cubic inches.
In No. 5, the maximum increase was 92 cubic inches.
In No. 6, the average increase was 47.5 cubic inches.

"3. As to the Depth of Inspiration.
"The rate of respiration either did not increase or was lessened;
and as the volume of air inspired was increased, the depth of inspira-
tion was greater so that the increased volume of air inspired at each
inspiration varied from 3 to 10.6 cubic inches. With this increased
depth, there was also a sense of greater freedom of respiration.

"4. As to the Rate of Pulsation.

"The rate of pulsation followed that of respiration, but in a less
degree, and was either not increased or was slightly decreased.

"Hence it was proved beyond all doubt that tea is a most power-
ful respiratory excitant. As it causes an evolution of carbon greatly
beyond that which it supplies, it follows that it must powerfully pro-
mote those vital changes in food which ultimately produce the car-
bonic acid to be evolved. Instead, therefore, of supplying nutritive
matter, it causes the assimilation and transformation of other foods

O'SHEA — ASPECTS OF MENTAL ECONOMY. H

"Hence, in reference to nutrition, we may say that tea increases
waste, since it promotes the transformation of food without supplying
nutriment, and increases the loss of heat without supplying fuel, and
it is therefore especially adapted to the wants of those who usually
eat too much, and after a full meal, when the process of assimila-
tion should be- quickened, but is less adapted to the poor and ill-fed,
and during fasting."

His experiments with coffee show an influence similar in a
way to that of tea. He says i1

"Of twenty-three experiments on myself and others there was from
half an ounce of coffee an increase in the quantity of carbonic acid
evolved of 0.98, 1.02, 0.9, 0.4, 1.16 and 2.54 grains per minute at dif-
ferent times, whilst the quantity of air inspired was increased 40, 34,
35, and 84 cubic inches per minute with the same experiments. Three-
quarters of an ounce of coffee did not give a greater increase, but
the actual increase was 0.68 and 1.68 grain of carbonic acid and 28
and 54 cubic inches of air per minute.

"The conditions, therefore, under which coffee may be taken are
very different from those suited to tea. It is more fitted than tea
for the poor and feeble. It is alsb more fitted for breakfast, inas-
much as the skin is then active and the heart's action feeble; whilst
in good health and with sufficient food it is not needful after dinner,
but if then drank should be taken soon after the meal. Hence in
certain respects tea and coffee are antidotes of each other, and we
know that they are now taken indiscriminately, although in a chief
action they are interchangeable.

"Coffee is an excitant of the nervous system, but not in the same
degree as tea. It produces sleeplessness in many persons when it is
taken at night, probably by exciting the heart's action, and preventing
that fall which is natural at night, and requisite to permit sound
sleep. I do not think that there is the same degree of reaction after
taking strong coffee as follows strong tea. It is needless to add, that
none of these effects may be marked if the infusion be very weak,
as is common among the poor, and in this respect it resembles very
weak tea."

I am not familiar with the results of experiments relating
to the influence of cocoa; but it is known that its active prin-
ciple, theobromine, resembles the active principles of tea and
coffee, theine and caffeine, and it is probable that its action in
the system is somewhat like these.

JOp. cit., pp. 365-367.

112 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

It must be apparent, then, that these beverages containing
alkaloids really operate in dissipating rather than in conserving
enera-v. Thev are doubtless of assistance to an organism that
needs to get rid of superfluous materials. One who does not
require all the energy of his food for mental or physical labor
may to advantage call tea and coffee to his aid to relieve his
system of a burden. But this is a situation which does not
commonly exist in student life. Students, as a body, are not
likely to consume more food than is required for the best effi-
ciency of mind and body even when the total amount of energy
it yields is expanded in profitable production. And then the
average college man or woman is illy prepared, from the finan-
cial point of view, to provide for the waste of food which the
habitual use of tea and coffee entails. It is recognized, of
course, that conditions may exist when tea, coffee, and similar
things have a therapeutic value ; but we are concerned here not
with the needs of the organism in disease but only in full health
and vigor.

The exhilaration which follows a cup of tea or coffee is sig-
nificant for the psychologist as well as for the student in the
practical affairs of daily life. This is possibly due to a paralyz-
ing effect for the moment upon the inhibitory or controlling
mechanisms in the central nervous system which report the true
condition of the organism, and seek to prevent it from passing
the safety line in its activities. To illustrate the theory by
fatigue: The fatigue sense, as has been said, exerts an in-
hibiting influence upon activity ; the rate and strength of move-
ments show decrease; mind and body become relaxed, and un-
der normal conditions the individual tends to fall asleep in or-
der that there may be repair of waste. When this sense reports
the status of the body in fatigue there is a feeling of depres-
sion, of lassitude ; but if its restraining power can be overcome
in any way there will apparently be a return of wonted vigor.
But what the welfare of the system requires at this time is rest
and food to restore dissipated energy, not incitement to still
greater dissipation ; and while in certain situations it may be

O'SHEA — ASPECTS OP MENTAL ECONOMY. 113

advisable to stimulate by weakening the controlling and warn-
ing functions of the body, yet to make this a systematic, daily
practice is to .render the organism in the end less efficient men-
tally and physically. It is not an over-statement to say that
a student living a normal life with all his powers under con-
trol, which requires, speaking neurologically, that his nervous
system should be in a state of thorough nutritive repair, — such
a student will not be benefited but. rather be injured by the stim-
ulations derived from habitual indulgence in tea and coffee.

Before taking leave of this subject I must quote the testimony
of Williams1 regarding his personal experience with tea :

"I recommend tea drinkers who desire to practically investigate
the subject for themselves to repeat the experiment that I have made.
After establishing the habit of taking tea at a particular hour, sud-
denly relinquish it altogether. The result will be more or less un-
pleasant, in some cases seriously so. My symptoms were a dull head-
ache and intellectual sluggishness during the remainder of the day —
and if compelled to do any brain-work, such as lecturing or writing,
I did it badly. This, as I have already said, is the diseased condi-
tion induced by the habit. These symptoms vary with the amount of
the customary indulgence and the temperament of the individual. A
rough, lumbering, insensible navvy may drink a quart or two of tea,
or a few gallons of beer, or several quarterns of gin, with but small
results of any kind. I know an omnibus driver who makes seven
double journeys daily, and his 'reglars' are half a quartern of gin at
each terminus — i. e., 1% pints daily, exclusive of extras. This would
render most men helplessly drunk, but he is never drunk, and drives
well and safely.

"Assuming, then, that the experimenter has taken sufficient daily
tea to have a sensible effect, he will suffer on leaving it off. Let
him persevere in the discontinuance, in spite of brain languor and
dull headache. He will find that day by day the languor will dimin-
ish, and in the course of time (about a fortnight or three weeks in
my case) he will be weaned. He will retain from morning to night
the full, free, and steady use of all his faculties; he will get through
his day's work without any fluctuation of working ability (provided,
of course, no other stimulant is used). Instead of his best faculties
being dependent on a drug for their awakening, he will be in the
condition of true manhood, — i. e., able to do his best in any direc-

1 Chemistry of Cooking, p. 257.
8

114 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

tion of effort, simply in reply to moral demand; able to do whatever
is right and advantageous, because his reason shows that it is so. The
sense of duty is to such a free man the only stimulus demanded for
calling forth his uttermost energies."

. To obviate the evils attendant upon the continual use of tea
and coffee Count Rumford made a suggestion many decades
ago which is being practically embodied today in the manu-
facture of a substitute therefor. He gave these directions for
the preparation of the substitute:1 Take eight parts by weight
of meal and one part of butter. Melt the butter in a clean
iron frying pan ; and when thus melted, sprinkle the meal into
it. Stir the whole briskly with a broad wooden spoon or spat-
ula until the butter has disappeared aud the meal is of a uni-
form brown color like roasted coffee, great care being taken to
prevent burning on the bottom of the pan. A small portion
of this composition was then to be placed in boiling water and
an infusion obtained in the same way as in the case of tea or
kindred beverages. This would answer one purpose, if none
other, for which many people imbibe tea and coffee, that they
may have a warm drink while partaking of solid food. Rum-
ford's substitute has been much improved upon in our own day
in the manufacture of cereal coffees which are in some instances
at any rate alike palatable and nutritious. It would certainly
be of advantage to a student in the economy of his energies
and his purse if he should reduce the quantity of his tea and
coffee, replacing it in whole, or at least in part, by Count Rum-
ford's substitute, or some other modern version of the same.
It perhaps should be said that one who has acquired great
fondness for the stouter drinks will. not at the beginning find
the substitute quite so agreeable to the palate because not so
stimulating; but I have been able to observe a trial made in
a boarding house in our own city where in several cases the
use of the substitute for a few days served to make it thoroughly
acceptable, and even replaced the older beverages in the novices,
favor.

1 Williams, op. cit, p. 245.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

115

§3. The Influence of Alcohol in Wine, Beer, and Other Bev-
erages in the Production and Expenditure of Force. — We come
now to discuss a group of articles demanding particular con-
sideration,— those containing alcohol in combination with va-
rious other ingredients, as found in beer, wine, whiskey, and
the like. It was not thought necessary nor perhaps desirable
to try to find out in our questionnaire how extensively these
are used by our own students ; but it is well known, of course,
that to some extent here, as elsewhere, alcoholic beverages are
indulged in. The composition of beer and wine, the beverages
most commonly drunk, reveals at the outset the fact that they
cannot be regarded as foods in the proper sense. The following
is the list of the chief compounds known to occur in beer •}

1. Alcohol, or spirits of wine, from 8 to 3 per cent.

2. Dextrin, about 4.5 per cent.

3. Albuminoids, about 0.5 per cent.

4. Sugar, about 0.5 per cent.

5. Acetic, Lactic, and Succinic Acids, about 0.3 per cent.

6. Glycerin, about .22 per cent.

7. Carbonic Acid Gas, about 0.22 per cent.

8. Mineral matter, about 0.3 per cent.

The following table shows the quantities of alcohol and other
elements contained in fair average samples of one imperial pint
each of eight different kinds of wines commonly consumed in our
region :2

Name of wine.

Hock

Claret

Champagne
Burgundy. .
Carlowitz. .

Sherry

Madeira .. .
Port

Alcohol
(absolute)

Oz. Or,

219
306
313
18
35
147
218
218

Tartar-
ic and
other
fixed
acids.

Or.

39

31

20

24

36

24

26

23

Acetic
acid.

Gr.
18
18
10
17
19
12
18
12

Sugar.

Oz. Gr.
None.
None.
1 120
10
None.
0 236
0 175
0 359

Ethers.

Gr.

e

5

6
5
4
5
6

Miner-
al mat-
ter.

Gr.

16

18

20

18

16

38

33

20

The principal constituent, aside from water, of whiskey, rum,
and brandy, like wine, is alcohol, which indeed is the princi-

1 Church, op. cit., p. 190.
'Idem., p. 194.

116 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

pie of primary importance in all alcoholic beverages. The
whole class, therefore, and especially in view of the subject we
have under consideration, is to be considered in respect of its
effect upon the central nervous system and not in regard to its
nutritive value.1 It has been observed by people from afore-
time that alcohol in its first effects usually, though not always,
increases the activity of mind and body : the senses apparently
become more acute, checks upon speech are released, and bod-
ily movement is augmented. This phenomenon has been
ascribed to the exciting influence of alcohol upon brain cells;,
it has been thought to act directly upon the perceptional, idea-
tional, and motor regions, inciting them by a kind of irritation
or inspiration, to heightened and intensified action. But we
get a different conception of the case if we look at it from the
point of view of modern neurology. At the risk of wearying
the reader, I repeat that an important part of the nervous
mechanism is concerned with co-ordinating the activities of
mind and body. Higher and more differentiated centers con-
trol and correlate lower and more fundamental ones. Now it
seems that the influence of alcohol in the organism may be ex-
plained most satisfactorily by supposing that it has a general
paralyzing effect upon nerve structures, first attacking the in-
hibitory system and nullifying its restraining power. This
produces temporary exaltation when one is depressed and a gen-
eral increase in activity due to the rebound of the system from
the constriction that had been placed upon it. But it is well
known that as the influence of alcohol increases in the organ-
ism the higher mental processes and the more delicate motor
co-ordinations are soon attacked; and ultimately even the most
fundamental functions are paralyzed when both mind and body
fall into a wholly disorganized condition. Intoxication means,
considered from one point of view, the temporary destruction
of psychical and physical functions w^hich it has taken nature

1 Since the above was written I have read Prof. Atwater's Report to the Mid-
dletown Scientific Association in which he takes the view that alcohol is a food ;
but he would. I believe, agree to the statement I have made that its effect upon
the nervous system is after all the vital matter for every one of us.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 117

an infinitely long time in the process of evolution to elaborate.
One would certainly not be extreme in saying that an intoxi-
cated person returns to the estate of the brute, since while he
is in this condition the higher cerebral structures, those which
hare been built in the last stages of the evolutionary process,
through which are manifested the highest attributes of the hu-
man mind, are rendered inactive, and the individual lives for
the time being upon a lower plane, when old reflex arcs again
become complete and have their way.. If from the point of
view of science there are such creatures as fools, then a man,
and especially a student, who will deliberately become drunk,
must certainly be catalogued in this group. Let it be remarked
in passing that no more pitiable or grievous spectacle can be
witnessed than that which is presented when a number of uni-
versity men, in whom should be evidenced the glory and tri-
umph of evolution, and who above all others should be the last
to yield mental poise and balance, its supremest blessing, — when
such men forfeit the right to manhood and voluntarily bring
upon themselves dissolution, intellectual, emotional, and phys-
ical.

The view which is here presented of the neurological influ-
ence of alcohol as a paralyzing agent upon nerve action and
control is not a wholly new one. I find that the eminent phy-
sician Harley arrived at this opinion some years ago, approach-
ino* thereunto bv a different route from that taken above. He
says r1

"Alcohol, when taken in small quantity, is in general said to act
as a direct cardiac stimulant, and its stimulating effect is supposed
to be due to its possessing the faculty of increasing the muscular
power of the heart. I take an entirely different view of the mat-
ter, and shall now endeavor to show how the increase in the force
of the heart's movements, the quickening of the pulse, the flushing
of the face, the congestion of the retinal blood-vessels, as well
as all the other visible appearances of accelerated cardiac functional
activity, are in reality in no wise due to the stimulating action of
alcohol, either on the heart's muscular tissue or the nerves supply-
ing it, but actually to the very reverse— namely, its paralyzing effects

1 Popular Science Monthly, Vol. 33, pp. 191-199.

118

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

on the cardiac nerve mechanism. Destroy or paralyze the inhibitory
nerve-center, or arrest its power of communicating with the heart by
dividing the vagus, and instantly its controlling effect on the cardio-
motor mechanism is lost, and the accelerating agent, being no longer
under its normal restraint, runs riot. The heart's action is increased,
the pulse is quickened, an excess of blood is forced into the vessels,
and from their becoming engorged and dilated the face gets flushed
and the retina congested — all the usual concomitants of a general
engorgement of the circulation being the result.

"The relative effects of alcohol and opium were found to be as fol-
lows:

In 100 parts of air.

Composition of employed air

With pure ox-blood

With pure ox-blood 5 per cent, of alcohol

With pure calf's blood

With pure calf's blood .005 grm. of mor-
phia

Oxygen.

Carbonic
acid.

Nitrogen.

20.9
10.58
16.59
6.64

17.17

0.002
3.330
2.380
3.47

1.00

79.038
85.09
81.03
89.89

81.83

Vol. at
O. C. at 1

metre
pressure.

30.96
14.91
18.97
10.11

18.17

Dr. Gaute,1 of the University of Zurich, has advanced a
somewhat similar opinion of the influence of alcohol in consid-
ering its relation to happiness; and his views are eminently
suggestive to the student who fancies that an efficient way to
meet difficulties is to forget them or imagine them out of exis-
tence or of less consequence and importance than they really
are, by maiming those powers of the mind that give an accurate
description of situations as they actually exist.

"*

* So the influence of alcohol is exactly as if the brain were
cut away. The man no longer stops to consider the whole situation,
to make use of impressions of former experiences stored away in the
brain, or weigh present obligations. How does it increase the feel-
ing of happiness? The body uses its powers in resisting the outside
forces which act upon it. Normally, there is a balance between body
and environment. If environment prevails we are discouraged; and
if we are able to prevail, our spirits rise and our happiness grows.
And it is not for the moment only, but we compare the accumulated
impressions of the powers outside of us with the powers which our
brains develop, and are happy or unhappy according as we feel our
superiority or otherwise. Just how much does alcohol interfere in
this balance of powers? It clearly cannot lessen the power of outside

3 Popular Science Monthly, Vol. 46, pp. 30-31.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 119

influences which harm us; it can as clearly not increase our own
powers in so far as they enter into this conflict with the outside
world— it rather makes us less skillful and able. What can it do,
then? It can deceive us. It dulls our appreciation of powers out-
side of us until they seem so much smaller that we are sure we can
conquer them, and so we gain a feeling of satisfaction."

Wilson1 has shown most conclusively that the drunkard is
simply a person in whom has become permanent the inco-ordi-
nations, the lack of control which is always induced temporarily
by any single spree. The balance-wheel is thrown out of gear
for good. The man is a creature of impulse, and that unfortu-
nately of a low type; the regulating, the subduing, really the
spiritual mechanisms of his being, have been paralyzed so often
that they are at last rendered permanently inactive. This ex-
treme case is cited simply to throw into clearer light the ordi-
nary effects of alcohol, which, although when taken in small
quantities may never produce great damage to the organism,
yet there must always be grave danger in its use. Maudsley,
after lifelong study of the causes of mental derangement, has
much to say2 of the baneful influence of this agent; and Mer-
cier, a student of insanity too, is unsparing in his condemna-
tion of alcohol, and a few of his words3 may be quoted in sup-
port of the views presented in these paragraphs, — that alcohol
is a factitious force-producer, and when used habitually results
eventually in the dissipation of energy, and sooner or later dis-
turbs the delicate mechanisms by which the organism is held
under the control of a vigorous will.

"Ask a man who has just left a city dinner to settle with you the
lease of a house, or a deed of partnership. He will naturally refuse.
If you press him, he will say that it is not a proper time to trans-
act business; and, if pressed further, will explain that to take him
now is unfair, for to such an important and delicate matter one
must come with a clear head. The admission is that the mind is
not now as vigorous as it will be tomorrow morning. There is a
slight enfeeblement. Partly from the fatigue of the day, partly from

1 Drunkenness, Part I. See also Eichardson, Ten Lectures on Alcohol, pp.
123-179.

2 See Responsibility in Mental Disease, pp. 285-286.
* Sanity and, Insanity, p. 316.

120 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

the effect of the dinner in drafting off a part of the blood supply from
the brain to the stomach, but chiefly from the benumbing effect of
the alcohol that he has imbibed on his highest nerve regions, his
mind is not as clear nor as vigorous as it is wont to be. The con-
fusion is not great; he can make an after-dinner speech of average
intelligence, can reckon his legal cab fare, and so forth, but he will
not trust himself to settle a delicate matter of negotiation. He feels
that the keen edge of his intellect is blunted. It is the very high-
est of all his intellectual faculties that have been dulled. Similarly
on the bodily side — he can walk perfectly straight, can light a cigar
without bungling, and button his overcoat with facility; but when
he tries to play billiards he finds 'his hand is out.' He is not cer-
tain of his strokes. He can no longer regulate his movements with
the nice precision that is required for success. Of bodily, as of men-
tal capabilities, he has lost the most elaborate, the most oelicate, the
most precise. At the same time that he shows these signs of defect
in his highest nerve arrangements, he shows some sign of over-
action of somewhat lower arrangements. By the annulling and placing
out of action of the highest, control is removed from those just below
the highest, which are consequently 'let go' and tend to over-act. The
staid and self-enclosed man of business becomes an expansive, jolly
companion. He gets on back-slapping, rib-punching terms with his
convives. He tells little anecdotes about his past career, with winks,
and wheezes, and warnings that they are not to be repeated to his
wife. His discretion and reticence are diminished by the loss of his
highest centers and he exhibits a phase of character inferior to his
usual standard. No one would call this state of things insanity;
but for all that it is the beginning of a process which, if continued,
would become insanity. It is the point at which divergence from the
processes of health begins to occur. It is not insanity, but it is the
rudiment of insanity. Let us trace the process further and see what
it develops into."

When one looks at tills subject from the standpoint of educa-
tion he sees that the university, student less than any one else
should need to quicken and intensify the psychic life by the
employment of an artificial excitant. While it is the testimony
of those who should know that the initial effects of wine are
stimulating to thought and feeling, and there is a general buoy-
ancy and perhaps elevation in the entire being, yet this advan-
tage can be secured in other ways more normal and therefore
more beneficial to the finest quality of mind. That mental

0'8HEA — ASPECTS OF MENTAL ECONOMY. 121

•exaltation which results from the enjoyment of beautiful art
and music and intercourse with inspiring people can readily
beget that fine ecstacy which has made wine so celebrated in
-song and story. There is surely more of lasting joy in becom-
ing drunk with grace and beauty than with wine; beauty ex-
erts an integrating influence, it adds to the vitalities of life;
while wine disintegrates and dissipates energies. Considering
that the university student has special obligations to the com-
monwealth by whose bounty he is receiving the blessings of
education, then he above all others should secure his mental
gladnesses and gayeties through means which will confer upon
him increasing power and balance rather than through those
alluring agents which may momentarily give pleasure but which
in the end are destructive rather than constructive.

The value of any food must be determined in a final analysis
by its force-producing capabilities. If beer, wine, and whiskey
impart energy to the organism this should be revealed in in-
creased activitv of mind and bodv. Research has shown in
some measure at any rate that instead of alcohol thus augment-
ing the amount of work which an individual can do, it actually
reduces it. Martin1 observes that the evidence adduced by
•competent observers is distinctly against the use of spirits by
soldiers in time of war. He says there is no cogent evidence
to show that alcohol is of service in sustaining bodily activity.
Hodge's investigations are of especial significance on this point.
Professor Hodge was enabled a few years ago to conduct a se-
ries of experiments under the auspices of the Committee of
Fifty for the study of the liquor problem, wherein he carefully
observed the mental and physical effects upon a number of dogs
of alcohol administered in the forms of beer, wine, and whis-
key. The results so far as they refer to the particular topic
under discussion — the value of alcohol as a force producer in
a living organism — may be presented in his own words :2

"During the second month after administration of alcohol spon-
taneous activity of both Tipsy and Bum became noticeably impaired.

^Treatise on Hygiene, Stevenson & Murphy, Vol. I, p. 487.

* Popular Science Monthly, March and April, 1897, and reprint.

122 BULLETIN OY THE UNIVERSITY OP WISCONSIN.

This gradually and steadily increased until, last spring, it seemed
to me from daily observation that the alcoholics were not much more
than half as active as the normals. How to secure an objective ex-
pression of this fact presented some difficulties at first. To put them
in large recording cages, such as we use in the laboratory to study
the daily activity of rats and mice, would clearly be an imposition
on a dog's good nature, and would possibly suppress his activity in
proportion to his intelligence. To watch four dogs during the twenty-
four hours would require four observers, and their presence would be
a disturbing factor.

"Pedometers were thought of, but none could be found suitably con-
structed for use with the dogs. Finally, Waterbury watches were
obtained, and, by removing the hair springs, weighting the balance
wheels unequally, and by proper adjustment of buffing pins so that
the balance wheel could move just far enough to release the escape-
ment, a watch resulted which ran only when shaken. After a month
of preliminary trials an adjustment was attained so delicate that the
watch could hardly be jarred so slightly as not to release the escape-
ment one tooth, and the two could be shaken, violently or gently,
and in any position for an hour at a time (fastened firmly together)
without showing a variation of more than two seconds on reading
the hands.

"The watches are now placed in stout leather pockets in specially
constructed collars and the dogs allowed to wear them. * * * The
watches were read every evening at exactly six o'clock. Bum is seen
to develop seventy-one per cent, of Nig's activity, and Tipsy only fifty-
seven per cent, of Topsy's.

"The watches, of course give us only the total quantity of spon-
taneous daily movement of each dog with no indication as to its
quality. Something to give a qualitative expression of strength, abil-
ity, and resistance to fatigue was devised, which consisted in a series
of competitive tests at retrieving a ball. The balls were thrown in
rapid succession across the university gymnasium, one hundred feet,
and a record was kept of the dogs that started for it and of the one
that succeeded in bringing it back. One hundred balls constituted a
test, and to throw them consumed about fifty minutes.

"In the first series, consisting of 1,400 balls thrown on successive
days, January, 1896, the normal dogs retrieved 922, the alcoholics 478.
This gives the alcoholics an efficiency of only 51.9 per cent, as com-
pared with the normals. Bum's ability in this series as compared with
Nig's is only thirty-two per cent. (See Fig. 18.) It was also noted
that Bum and Tipsy were much more easily fatigued than the nor-
mals.

O'SHEA ASPECTS OF MENTAL ECONOMY. 123

"A second series, of 1,000 balls, November, 1896, in which Bum and
Nig, were tested, gave similar results. Nig shows fifteen per cent, ot
Bum's fatigue. Expressed in other words, Bum lies down to rest
6.7 times to Nig's once."

In discussing the results of these experiments, Dr. Hodge
quotes Professor Gaul£ to the effect that once during the strain
of his Staatsexamen he suddenly stopped his wine and beer and
was surprised to find how much better he could work. An emi-
nent Leipsic professor has said that German students could do
twice the amount of work if they would let their beer alone.
Dr. August Smith found that moderate doses of alcohol not
sufficient to intoxicate lowered psychic ability to memorize as
much as seventy per cent. *

From whatever position, then, we regard the influence of
alcohol upon the force-generating power of the organism, we
find on every occasion that it has only a deleterious issue, ex-
cept of course when it is employed as a therapeutic agent. 2 The
practice in which students ofttimes indulge of exciting good
cheer by a few glasses of beer or wine must certainly in the
long run lessen the efficiency of mind and body. When a great
feat is to be undertaken, as upon the football field, alcoholic
beverages are absolutely prohibited the contestant. A student
should regard his daily tasks as all being great ones for which
he must prepare himself most effectively mentally and phys-
ically. The ordeals of the student in his immediate class-
room duties and in the more important businesses of post-uni-
versity life should demand as clear and vigorous a brain and
a^ agile and serviceable a body as the athlete requires to meet
the difficulties which he will encounter in the arena.

§ 4. The Influence of Tobacco Upon the Production and Ex-
penditure of Force in the Organism. — While alcohol operates
to throw off the brakes which nature places upon the organism

1 Hodge, op. cit., p. 25.

*Atwater's investigations already referred to seem to present alcohol in a more
favorable light. Small quantities of alcohol are not injurious, says Atwater, but
yet there are grave dangers in its use, since it is difficult for the habitual
drinker to avoid excesses.

12-4 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

when danger is sighted ahead, tobacco seems to have a directly-
contrary influence. It is the common testimony of smokers
that after a day of severe labor or intense excitement or exer-
tion of any kind, when the mind is chaotic, uncontrolled, and
repose is impossible, — in such an event, the cigar or the pipe
has a soothing, calming effect. Nicotine seems to act as a
stimulant to the inhibiting centers of the nervous mechanism.
In view of this well known action of tobacco, it can be seen
why in cases of fatigue when the mind cannot be held in check
and energy is being wasted despite efforts at conservation, — in
such a situation tobacco must be regarded as a conserver of
force. It aids the organism to get hold of itself, to become con-
trolled. This is especially true when, as smokers so frequently
testify, tobacco skillfully wooes Morpheus when nothing else
will entice him to one's bedside.

But this does not of necessity imply that tobacco is a valua-
ble auxiliary to the student's dietary. It is not too much to
suppose that under normal and healthful conditions a student
will rarely reach the point where he will need any other seda-
tive agent than that furnished by an abundance of nutritious
food, vigorous exercise, and refreshing sleep. As a matter of
fact, though, our young men taken as a whole do not smoke
because they feel the need of the soothing influence which it
affords; they smoke because custom dictates it. This is evi-
denced by the irrational way in which they do it; and it is
suggestive, too, that practically all of the law students who re-
plied to our questionnaire smoke, while about 55 per cent, of
the "Hill" students are "abstainers." To smoke immediately
after breakfast is as foolish as it is useless ; for at such a time
tobacco rather hinders than helps the organism to accomplish
the tasks before it; except possibly in those instances when the
system has become so permeated with nicotine that it is, in com-
mon with the well-known effects of opium, creating an abnor-
mal desire which is unrelenting every hour and minute of wak-
ing life. As Richardson well says in his Diseases of Modern
Life:1 When mental labor is about to be undertaken a pipe

'P. 316.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 125

produces in the majority of people a heavy, dull condition,
which impedes digestion and assimilation, and interferes in
some degree with that "motion of the tissues which constitutes
vital activity." But when the mind is occupied for a long
time, so that exhaustion supervenes, a pipe gives to some
habitues a feeling of relief; it soothes, it is said, and makes pos-
sible clear thinking. Few men become so habituated to the
pipe that they can begin the day well on tobacco. "Many try,
but it almost invariably obtains that they go through their la-
bors with much less alacrity than other men who are not so
addicted."

126 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

CHAPTER V.

THE PREPARATION" OF FOOD HOURS FOR MEALS.

§1. The Philosophy of Cookery. — While the composition of
a food is an important factor in determining its worth, yet a
more important factor still, perhaps, is the manner in which it
is prepared for use in the organism, — the manner in which it
is cooked, that is to say. This is seen to be true when it is
realized that man is a cooking animal, and as such is distin-
guished from the rest of creation. It seems to be clearly re-
vealed in his constitution that he was not designed to take into
his stomach in the raw condition in which they are found in
nature most of the articles which constitute his dietary. He is
not a graminiverous animal ; he lacks the long alimentary tract,
the special stomach, and the apparatus for secreting large quan-
tities of saliva which is possessed by the cow and other grain
munchers. The crops of birds probably fulfill somewhat the
same function in the digestive processes that the second stomach
does in the ruminants ; and in both cases this elaborate apparatus
is necessary in order to transform starch and other food ele-
ments into assimilable products. Again, man does not appear to
be adapted to eat meat unsubdued by heat ; sentiment if nothing
more would forbid his doing this. The human species has pro-
gressed to the point in the evolutionary scale where it can call
to its aid forces which are capable of advancing foods as they
are found in their native state far along in the process of di-
gestion, so that when taken into the system they may be assimi-
lated with comparatively little delay or expenditure of vital en-
ergy.

It may be observed in passing that in all likelihood this ac-
complishment more than any other has contributed to the rapid
mental progress and present superiority of mankind. Spencer1

1 Education, chapter on Physical Education.

O'SHEA ASPECTS OF MENTAL ECONOMY. 127

has pointed out that animals which live upon coarse, indigestible
foods, as the cow and the sheep, are, considered in respect alike
of physical power and mental acuteness and vivacity, relatively
inferior in the scale of being. Now, it seems a safe inference
from the evidence everywhere at hand that the quota of energy
which can be expended in mental and physical activity will be
determined by the ease with which this may be obtained in the
process of nutrition. It is a fact of daily experience, probably
as common in student life as elsewhere, that when the stomach
is overloaded with indigestible and waste materials the mind is
inert and confused, and the body little disposed to vigorous or
lively activity. Let any one recall his mental and bodily status
after assisting at the ordinary Thanksgiving feast, or perhaps
even the familiar Sunday dinner. Sabbath afternoon is so fre-
quently a time for loafing in both body and mind, not because
one wants to rest but because he cannot arouse himself. Many
of our students have a still more impressive experience ; not in-
frequently they are required to rush off precipitately to their
university duties directly following upon a meal which taxes the
organism to the utmost, — oatmeal cooked a half hour or less,
fried potatoes, fried meat or eggs, hot bread and cakes,
and coffee, — a combination which, as will be shown later, is more
than a match for the most energetic and powerful digestive
mechanism. At such a time the mind works slowly and inac-
curately ; and the philosophy of the thing is not at all abstruse.
When food is taken into the system the organism will if neces-
sary turn its energy wholly to extracting the nutrition contained
therein. Suppose then that a considerable amount of half di-
gested starch and other food materials find their way to the
stomach; there is needed at once force to transform these into
assimilable substances. The blood, rushing to the appropriate
organs to supply the required digestive agents, must, of course,
be withdrawn from the service of the cerebral and muscular
systems. When, on the contrary, food is eaten which is nearly
ready for assimilation, the organism can while attending
to the now easy labor of digestion engage also in a measure in
mental or physical work.

128 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

§2. Modes of Cooking. Local Practices with Criticisms. —
As has been said, the primary purpose of cooking is to advance
the assmiilability of foods as they are found in the raw state so
as to relieve the digestive apparatus of much arduous drudgery.
For the most part this is accomplished by applications in one
form or another of heat. In the cookery of meats it should be
the aim to soften tissues and develop flavors which will excite
digestive juices; and those modes will be most efficient which
will attain these ends while not destroying the nutritive proper-
ties. In roasting, baking, and broiling heat is applied directly
to the surface of the meat ; whereas in boiling and frying it is
conveyed by convection, in the first instance through water, in
the second through oil. ISTow, one of the most valuable elements
of meat, albumen, exists in considerable quantities as a juice;
and this escapes with comparative ease in boiling when the meat
is put into cold water and gradually raised to the boiling tem-
perature. When the meat is thrust into boiling water at the
outset, however, the pores in the surface become closed in such
a way as to prevent in a large degree the loss of the juices, and
the cooking may proceed with comparatively little waste. The
most economical modes of cooking this article, though, are those
in which a high degree of heat is applied directly, as in baking,
broiling, or roasting. Frying is the most objectionable method
of all, and especially the sort of frying wThich one finds in the
average boarding-house or even in the majority of homes.
Here the cook places a little oil in the bottom of the frying pan
"to keep the meat from sticking to it," and heats it to a point
at which the fat is partly decomposed ; she never imagines that
in frying cooking should be accomplished in the same way as
in water except that a different medium is used. What is to
be secured is the transmission of heat through the oil. Cooking
in this way would not be so objectionable if a bath of fat were
used instead of a little in the bottom of the frying pan ; although
even here food is liable to be made indigestible by becoming
fat soaked, so to speak. It is of course well-known that the fat
which incases the nutritive elements in fried meats, eggs, and

O'SHEA — ASPECTS OF MENTAL ECONOMY. 129

the like digests lower down in the digestive tract than the sub-
stances themselves, so that these latter are held in the stomach
for a long period, resulting usually in fermentation, and greatly-
overtaxing the stomach.

An examination of the returns from our questionnaire shows
that meats, potatoes, eggs, and cakes are as often fried as cooked
in any other way; and this cannot but be regarded as a very
serious defect in local practice. And I know from personal ex-
perience that the frying which is done in some places here ren-
ders the food highly indigestible. A breakfast of fried pork,
fried eggs, fried potatoes, fried pancakes, and doughnuts must
very successfully prevent for several hours vigorous activity in
the head of almost any student. There is no danger in saying
emphatically that food prepared in this way is unfit for the needs
of a student or, in fact, of any civilized being ; and it may not be
out of place to observe that the state is bestowing its favors in
an unprofitable manner in attempting to educate an individual
who habitually regales himself on fried stuffs, and especially
such a variety as the landlords in our locality provide for their
guests.

But the cooking of meats, bad as this is even, is not so de-
fective in Madison boarding houses, as the cooking of starch
foods, — the cereals, bread, vegetables, cake, and the like. It
las previously been indicated that starch in order to be incor-
porated into the system must become converted into dextrin.
This is accomplished in the ordinary process of digestion by in-
salivation, wherein the active digestive principle of saliva is
brought into contact with the starch granules of food. Starch
may, however, be digested in other ways. It is well known,
for instance, that the nitrogenous principle, diastase, obtained
in malting, possesses the power to carry starch along through
several of the stages essential to complete conversion into dex-
trin. It is also known that digestive changes may be wrought
by the application of dry heat to starch. If you place starch
granules in an oven heated to the temperature of 300°, they
9

130 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

are not apparently affected at all ; but if you increase the tem-
perature 100° or thereabouts they will suddenly be transformed
into dextrin. The change is an isomeric one, for dextrin is of
the same composition as starch.

Now, the primary purpose in cooking the starch foods placed
on our tables should be to convert the starch so far as possible
into dextrin. Starch, as it is obtained in grain foods, cannot
be converted into dextrin without subjecting it for a long time
to heat, either directly or through convection in cooking in
water. The boiling of raw oatmeal for say thirty minutes will
not in all probability suffice to carry the starch far along in
the process of digestion, and this work must be completed after
the food is taken into the stomach if much nutritive value is to
be derived from it. On the other hand, if the cooking had
been carried on for a longer period less would have been left
for the stomach to do, which is the great object to be attained
in the cooking of these foods, — the relief of the digestive appa-
ratus. The processes essential to complete starch digestion
have been excellently set forth in a pamphlet presenting the
results of experiments prosecuted in the food laboratories of the
Battle Creek Sanitarium, in which it is shown that "water-
brash" and other dyspeptic symptoms so common among the
Scotch Highlanders is due to the excessive use of "Scotch brose,"
which is simply raw oatmeal stirred up in hot water. The prev-
alence of indigestion in our own country, too, is due princi-
pally to the same cause, — the use of starchy or cereal foods in
an uncooked or imperfectly cooked condition. The pamphlet
goes on to say that :

"The bread of the olden time consisted of thin cakes formed from a
mixture of flour and water, well kneaded and baked on a tin or stove
kept hot by a glowing fire. Bread prepared in this manner is ready
for prompt digestion and assimilation.

"The transformation of starch into sugar — in other words, the diges-
tion of starch — takes place by stages. The starch is first converted
into

"(a) Amylo-dextrine, or soluble starch. This is the form in which
it is found in well-boiled paste and in ordinary baker's bread, in so-
called ready-cooked breakfast cereals, and in mushes, gruels, vegeta-
ble soups, and similar preparations of starch.

O'BHEA — ASPECTS OP MENTAL ECONOMY.

131

"The third stage is that of (c) achroo-dextrine, that in which the
starch is found in such perfectly cooked cereal foods as zwieback,
granose, and granola, and in the outer browned portion of the crust of

bread.

"In the second stage (b) the starch is further transformed into
erythro-dextrine, the form in which it is found in what might be
termed the half-cooked condition of well-baked ordinary baker's bread,
in crackers, rolls, gems, and similar foods.

"The fourth stage is maltose or sugar, the final results of starch
digestion. The digestion of starch is accomplished in nature by the
action of so-called ferments or diastases. These are found abundantly
in both the animal and vegetable kingdoms, — in animals in the saliva
and other digestive fluids. In grains, the starch digesting ferment
or diastasis is found just beneath the bran, ready to form sugar for
the nourishment of the young plant. The starch found in green ap-
ples and other fruits is, by the process of ripening, converted first
into the various ferments or dextrines exclusively, and finally into
sugar.

"The formation of the last form of dextrine is indicated by the ap-
pearance of a slight brownish color in the digesting mass. One
additional step only is necessary to convert the starch into sugar.
Heat is not capable of producing this step in the process, but when
achroo-dextrine, the last stage of heat digestion, the perfectly cooked
starch is brought into contact with the saliva of any other starch-
digesting ferment, the formation of sugar takes place instantaneously.
In other words, by the application of heat of sufficient degree for a
sufficient length of time starch may be converted first into amylo-
dextrine is produced by a temperature sufficient to cause the hydra-
tion or gelatination of starch in the formation of paste by cooking of
starch or flour. Longer cooking, or cooking for a short time at a
temperature above the boiling point of water, advances starch one
step along in the process of digestoin to the stage of erythro-dextrine.
Exposed to still higher temperature for a proper length of time pro-
duces achroo-dextrine.

"Raw starch, on the other hand, when exposed to the action of the
saliva is not changed at all. Slightly cooked starch, that is, amylo-
dextrine or fluid starch, is converted into sugar only by the prolonged
action of the saliva. Erythro-dextrine, or imperfectly cooked starch,
is converted into sugar somewhat more quickly by the action of the
saliva, but in achroo-dextrine, or perfectly cooked starch, the trans-
formation takes place as soon as it is brought into contact with the
saliva. It is for this reason that a brown crust of bread, zwieback,
and well-toasted granose develop a distinctly sweetish taste when
chewed.

132 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

"Our modern methods of bread-making, in which, the dough is formed
in large masses or loaves, or small masses under the name of bis-
cuits, buns, rolls, etc., present the starch or farinaceous elements of
cereals in a half-raw, imperfectly cooked condition, prepared to inter-
fere with digestion, rather than to promote this most important vital
process. Half-cooked mushes and porridges assist in the work of mis-
chief, and as a result, the American people have come to be almost
universally afflicted with amalaceous dyspepsia, or starch indigestion.
This fact explains the extensive use of malt preparations, and the re-
cent introduction of various starch-digesting ferments or diastases of
various origin, some of malt, others from vegetable fungi."

It is then to be very greatly desired that those who provide
food for students should take especial care in the cooking of
cereals and breads. While it is of supreme importance that
whenever starch foods are eaten they should be thoroughly
cooked, yet this is especially necessary in respect of the morn-
ing meal when a stomach full of half cooked starch will be a
serious drawback to the student during the best hours of the
day. It may as well be recognized that no matter how skillful
the teaching it must fall on barren soil if it is received by those
who are devoting all their strength to breaking up starch.

Poods, as for instance, Malt Breakfast Food, Granola, etc.,
are now being manufactured which are either subjected to the
degree of heat necessary to carry starch quite a ways along in
the process of conversion into dextrin, or the same end is at-
tained by malting; and these, it seems, should be found
more freely upon the tables of students than is indicated
in our returns. I have, however, spent some days at one
Jboarding house in the city where the morning cereals seemed
all thoroughly cooked, and were most palatable and nutritious ;
but I have obtained dishes at other places where students board
that were not fit for mortal man to entertain in his system.
The freer use of thoroughly baked, or better still twice baked
tread, is much needed in our community. In the baking of
bread in the ordinary way the middle of the loaf does not rise
above 212°, although the outside reaches 400° or more. Many
people choose the crust for its more agreeable taste, which re-
sults from the conversion of the starch into dextrin by the ac-

O'SHEA — ASPECTS OP MENTAL ECONOMY. 133

tion of heat in baking. It is at the same time more digestible,
and so in reality more nutritious.

A word should be said respecting the cookery of one or two
other common articles of food — and first, potatoes. The usual
mode in our own locality is to boil them peeled and mash them.
Now, one of the most valuable nutrient elements in the potato
is the salts of potash, which in a jacketless potato readily es-
capes into the water during boiling, and especially if the tubers
are placed in cold water at the outset. Jackets or no jackets
then is the vital question, and we are compelled to decide in
favor of the affirmative. In countries where the people cannot
obtain these salts in meats and other foods, experience has
taught them to cook the potatoes always without peeling. Bak-
ing, though, is altogether the most desirable mode of cooking
the potato. By this method all the salts are preserved; while
in boiling, even with the covers on, the potato suffers some loss.
It is very evident from our returns that a reform is needed in
the cooking of such a substantial and yet simple article of food
as the potato.

It is probable that one of the most poorly cooked foods in
our locality is the egg. The method is almost universally fry-
ing. To say nothing about the chemical changes which this
produces, it is enough to point out that the albumen becoming
incased in animal fat partially decomposed is well nigh invul-
nerable to the attacks of the digestive juices. On the other
hand, anyone who has tried immersing an egg for eight minutes
or so in water about twenty degrees below the boiling point
and which has been taken off the stove, will know that no part
of the egg is cooked hard and yet heat has penetrated through-
out the whole. An egg cooked in this way is highly digestible
and possesses a delicious flavor ; for a morning meal it will sup-
ply the energy needed for the day's work much more speedily
and with less expenditure of internal forces than a fried egg or
an egg boiled in water at a temperature of 212°.

134 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

§3. Hours for Meals. — It is well known, of course, that a
heavy meal makes demands upon the energies of the system
for a considerable period ; mind and body alike are less efficient
while the early stages of digestion are in progress. The pros-
perity of digestion itself requires muscular repose for a time;
and when three "square" meals are disposed of daily
a relatively large part of waking life must be devoted to the
interests of the stomach, and the head and hands must suffer
thereby. It would seem a much wiser scheme, and one which
is being adopted now in the cities especially, to get most of our
nutrition in two repasts ; and if we have a third, to make it
exceedingly light so that it will not interfere seriously with
either mental or physical activities. A business man in the
city would not think of dining at midday; he lunches simply,
and his luncheon really serves the purpose of a little recreation
rather than of gaining nutrition.

Our students enjoy three meals a day, all of about the same
proportions, so far as can be judged from the bills-of-fare. It
is true they have at noon, with a very few exceptions, what is
called dinner, and this is supposed to be the principal repast
of the day, although it seems to be so only in the sense that per-
haps heavier and more indigestible viands are discussed. But
a large number of our students attempt their hardest work in
the afternoon immediately following their experience at table;
their study hours are in the majority of cases from 2 to half
past 5 ; and it is surely not an overstatement to say that no
brain is in good workable condition when handicapped by a
stomach full of such things as are indicated in the midday bills-
of-fare given in Chapter III. [Nearly every one of our students
— all except fourteen — reported that from 2 to 4 was the dull-
est time in the entire day. From 7 to 9 is also a period of
marked mental depression. One would suppose that the mind
would be worn out as the hour for retiring approached, and
that it would be most obtuse then; but only eight out of the
whole number of students reporting said they were dullest at
bedtime ; the others were stupidest after meals.

0 SHEA ASPECTS OP MENTAL ECONOMY. 135

A reform in respect of the hours for gaining nutrition is as-
suredly needed in our community. It would seem as if the
majority of those who make a business of boarding students
make no business of it at all. If they were engaged in any
other calling they would be obliged to minister to the well-being
pf those whom they served ; but not so with most of the land-
lords and landladies who care for students. So many people
seem to harbor the opinion that a student's welfare does not
need special consideration anyway ; it is an easy thing to study
and the question of special food and appropriate times for eat-
ing is of little importance. But we need to have present prac-
tices modified so that students will at midday have a light
luncheon of very digestible and nutritious foods j then at half
past five or thereabouts should come a more substantial meal,
perhaps the principal one of the day. It should be said in
this connection that the last repast ought not to be eaten much
later than this, since it is important that the digestion of this
meal should be completed before bedtime. The stomach is not
active during sleep, and foods remaining therein during the
night are certain in most instances to pass through fermentative
processes, seriously disturbing the normal functioning of the
digestive system. Hardly any one can discuss a late banquet
without his tongue the next morning revealing his dissipation ;
the germs which have been prospering during the night have
installed themselves in every part of the mucous membrane
which is accessible to them.

At Columbia University most of the students partake at mid-
day of a simple luncheon of milk and bread, and perhaps a
sandwich, obtained at the University refreshment stand; and
after an hour's social chat, go back to their work in the library
and laboratories. This seems a much more rational way than
,to rush headlong home to a big dinner and rush back in the
same manner to recitations and other work, or escape to one's
room to doze away two or three profitless hours. This gives
one both a bad stomach and a bad conscience, and results eventu-
ally in an empty head. May we not hope that some day there

136 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

■will be near the campus of our University a refreshment booth
offering the most wholesome, palatable, and nutritious foods at
slight cost, so that students may spend in the library, in the
laboratories, and in general social intercourse on the campus
the time which is now wasted in rushing to a "square" meal and
recovering from the same ?

During the winter of 1892-93 an experiment was made along
this line at the Boston School of Gymnastics in serving lunch-
eons to women students at 15 cents each. The manager, Miss
.Wentworth, kept a record for one month of the amount of foods
furnished, with their nutritive values ; and while I believe more
nutritious and more easily digested articles, as I have indicated
in Chapters III and IV, could be furnished now than appeared
in this record, yet it is suggestive regarding what could be done
for students in our midst without departing in any way from
established custom respecting articles of diet.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

137

Statement of one month's luncheons served to students (women) five
days in the week, beginning February 1, ending February 28-
(Atkinson, op. cit.)

February 1st:
Beef broth , . .
Two rolls —
Gingerbread.
Butter

February 2d:
Baked beans .
Brown bread.

One roll

Butter

One orange . .

February 3d:

Escalloped meat.

Rolls

Butter

Apple sauce

February 6th :

Vegetable soup .

Rolls

Butter

Apricot sauce . .

February 7th :

Potato soup

Rolls

Butter

Two baked apples.

February 8th :

Pea soup

Rolls

Butter

Apple cake

February 9th :
Beef hash —

Rolls

Butter

Apple sauce .

February 10th:
Oyster soup .

Rolls

Butter

Prune sauce.

February 13th:

Beef croquettes . . .
Potato croquettes.

Rolls

Butter

Baked apples

February 14th:
Fish chowder

Rolls

Butter

One orange . . .

Ounces

Food Value in Ghams.

P rote id.

9.7 1
4.0 I
0.7 f
6.0 J

6.4 "I

4.0 I

0.7 |

5.3 J

9.6
4.0
0.7
5.3

4.0

4.0
4.0
0.7

8.0

10.0
4.0
0.7
5.3

2.63

2.63

32.2

20.0

15.0

23.6

33.1

20.9

16.8

22.2

Fat.

Carbohy
drates.

20.4

35.6

26.8

20.9

24.9

35.4

24.0

25.9

22.7

30.0

Calories.

128.4

131.4

138.8

92.1

131.5

126.1

136.5

108.0

111.4

101.2

817.5

979.3

912.2

648.2

826.1

938.3

911.8

762.5

738.8

778.1

138

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Statement of one month's luncheons served to students (women). —

Continued.

Ounces.

Food Valt/e in

Gkams.

Calories.

Proteid.

Fat.

Carbohy-
drates.

February 15th:

Tomato soup

9.7 "1
4.0 !

o.7 r

3.5 J

4.0 "1
4.0 1
0.7 f
8.0 J

8.4 1

4.2 |
2.0 !-
0.7

5.3 J

9.6 1
4.0 !
0.7 f

5.3 J

9.4 1

4.0 !
0.7 f
4.0 J

Z 8.4 1
4.2 1
2.0 1-
0.7 1

5.5 J

4.5 1

4.0 |
0.7 (
5.0 j

9.7 1

4.0 i
0.7 f
8.0 J

9.6 1

4.0 !
0.7 f
6.0 J

9.8 1
4.0 [

0.7 r

4.0 J

19.1

26.8

26.3

13.6
26.3

26.3

24.0
15.0
19.1
23.6

26.3
24.0

35.6

23.1
20.4

35.6

34.0
19.5
24.9
35.4

103.0
109.8

131.4

107.0
128.4

131.4

115.2

108.4
139.7

126.1

•

Rolls

Butter

739.0

Doughnuts

February 16th:

Escalloped fish

Rolls

Butter

777.2

February 17th:

979.3

Butter

February 20th:

Rolls

704.2

February 21st :

Rolls

817.5

February 22d:

979.3

February 23d :

Escalloped oysters

Rolls

Butter

880.3

February 24th:

Rolls

Butter

681.8

February 27th:

Rolls

Butter

875.9

February 28th:

Rolls

935.3

22.8

27.1

120.2

827.4

O'SHEA — ASPECTS OP MENTAL ECONOMY. 139

CHAPTER VI.

INDIVIDUAL PECULIARITIES IN DIGESTIVE CAPACITIES.

§1. The Theory of Individual Differences. — There seem to
be two great forces that vie with one another in planning and
directing the construction of every new being ushered into the
world. The first is heredity, Which seeks to reproduce without
modification in the offspring the characteristics of the parents ;
the second is variation, which seeks to differentiate the young
from their ancestors — to beget in them modified structures and
functions.1 As a result of the interaction of these forces it
happens that while members of the human species, for instance,
are much alike, still each is probably distinguished by some
purely individual features either in the architecture of the body,
in the workings of the vital machinery, or in mental tendency
and capacity.2 These differences are probably as marked in
respect of digestive functions as of any other; and it is not dif-
ficult to appreciate this when it is realized that the transforma-
tion of food is brought about through the offices of various di-
gestive fluids. Each food element has its particular digestive
agent, — starch requiring a special one, albumen another, fat
.another. Now, it happens that people differ regarding the
quantity and quality of each of these digestive agents ; this per-
son falls short on the one essential for the disposition of starch,
another generates free hydrochloric acid in excess of that which
is actuallv needed or which is conducive to the well-being of the
organism, and so on. It results then that we all have our ldio-

*Cf. Bateson, Materials for the Study of Variation, London, 1894, pp. 1-80.
Darwin, Origin of Species, entire book ; Hoffding, Outlines of Psychology, p. 348,

■et seq.

2 See for a discussion of individuality in the mental sphere, — Bain : A Study
of Character, London, 1863 ; Ribot : Psychology of the Emotions, chap. XII ;
Paulhan : Les Characteres ; Perez: Caractere de I'enfant et de I'homme; Lotze :
Microcosmus, Bk. VI, chap. II; Queyrat : L' imagination chez I'enfant; Galton ;
Mental Faculty, chap, on Mental Imagery.

140 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

syncracies regarding the articles from which we can best ob-
tain our nutrition, and the viands we can indulge in with im-
punity. One who has much difficulty in dealing with starch
will find it easier ordinarily to secure his albuminoids from
flesh or nut foods than from the cereals or other vegetable prod-
ucts; although, to repeat what was urged in preceding para-
graphs, by proper cooking starch may be largely pre-digested,.
making it acceptable to the most whimsical stomach. An acid
stomach cannot tolerate sour fruits, vinegar, or other acids, while
a "hypopeptic" individual enjoys and needs an abundance of
fruit acids. And the principle holds in respect of many an-
other digestive peculiarity.

§2. Concrete Examples. — To impress the principle of indi-
vidual peculiarities in digestive powers there will be given here
graphic illustrations1' of actual analyses of the stomach fluids
of two persons of the same family securing their nutrition from
the same table. The analyses were made in the Laboratories
of Hygiene of the Battle Creek Sanitarium according to meth-
ods devised by Golding Bird of England and Hayem and Win-
ter of Paris, and extended and perfected by J. H. Kellogg. In
the following brief explanation of the methods of examination
I follow Kellogg2 principally. In order to make the analysis
it is necessary to extract the contents of the stomach after there
has been eaten a given quantity of food the composition of
which is thoroughly understood; and, of course, a certain
amount of time must be allowed for the action of the stomach
upon the^food. By chemical analyses of the stomach fluids it
is then possible to determine the relative amounts of the sev-
eral digestive agents, and so to calculate the working power, as
it were, of the stomach, indicating whether it is normal in all
respects or whether it varies therefrom in regard to any of the
digestive processes. In making the test at Battle Creek the

'I am indebted to Dr. J. II. Kellogg and The Modern Medicine Publishing Co.
for the use of the plates of the charts.

'Methods of Precision in the Investigation of Disorders of Digestion — Modern.
Medicine Publishing Co., 1899. Also Modern Medicine Library, No. 1, May, 1896.

BULL. UNIV. WIS

., SCI.

5ER.

VOL 2

, PLATE 1

GRAPHIC REPRESENTATION

Of the Results of the Chemical Examination

of Salivary and Gastric Digestion.

NO. 8938.

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BULL. UNIV. WIS

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SEfl

VOL 2

, p

LATE 2

GRAPHIC REPRESENTATION

Of the Results of the Chemical Examination

of Salivary and Gastric Dige

stion.

NO. 11599.

X

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.Vo

1.170

.170

.024

.145

.130

i.70

.1G0

.160

.023

.135

.120

fl.60

.40

.SO

.so

180/

.80

.60

,80d

.80

.150

.150

.022

.125

.110

Jl.40

. 7V>

. 75

• 7< >

.75

.50

.75

.140

.140

.021

.m

.100

1.20

^ Ik

• * y

.70'

.70

• IV

.70

.40

.70*

.70|

<

.130

.130

.020

•!M

.090 1 1.00

.65

.65

.6. >

« t-«p

.65

.30

.65 £

.65 2

^r*eo

.120

.018

.095

yosol .90

.60

,60

.6<»

.60

.60

.25

•«<>!

.60 a

01

a
0

>

.ll\

.110

.01G

.085

Wo

.80

,551

■""ToVji'

. .5<i

.55

.55

.20

.55 o

.55|

.100

\100

.014

.iD75

.Wo!

.70

.50

.50

\ .5* •

.50

.50

.15

.50*

.•>o <■

r

.085

.085

.012

/065

.oW

.60

.45

.45

\i i>

.45

.45

.12

.455

.45^

.070

.07»

.010

/.055

.0^

.50

.40

.40

\4o

.40

.40

.10

.40 £

„ a

.85 g

• 40S

1.055

.055\

.008 ](.045

.030

.40

.35

.35

.*>

.35

.35

.08

.35

.040

.040

1.006J

.035

.020

.30

.30

.30

.&>

.30

.30

.06

.30 H

.30

1.025

.025

\o04/

.025

.010

.20

.20

.20

.20

.20

.20

.04

.20

.20

55

.010

.010

•W

.010

.005

.10

.10

.10

.10

.10

.10

.02

.10

.10

l_l_l

1.000

.oooj.M

.000

.000

.00

.00

.00

.00

.00

.00

.00

.00

.00;

m

n

a b(D

b(2)

c

y

z

O'SHEA — ASPECTS OF MENTAL ECONOMY. 141

subject is required first to abstain from all food for ten or twelve
hours ; and lie is then given to eat a bowl of Granose, a dry
wheat product, He is not allowed any fluids at this test meal.
After one hour the contents of the stomach are extracted and
subjected to physical and chemical examination. The chemi-
cal examination reveals, to begin with, the amount of chlorine
present in different forms, which determines the acidity of the
stomach and so the power of proteid digestion. This analysis
reveals three main types of digestive disorder, — hyperpepsia,
hypopepsia, and apepsia. Speaking in a general way, hyper-
pepsia denotes an excessively acid stomach, hypopepsia a stom-
ach in which there is not enough of acid for proper digestion,
and apepsia a stomach in which there is almost no native power
of proteid digestion. These types of stomachs are indicated in
the charts by the different colored areas, the red denoting the
hyper-acid stomach, so to speak, and the blue the sub-acid stom-
ach.

The test for chlorine in its different combinations shows, in
the first place, the total acid condition of the stomach, which
is denoted in the chart by A. Taking a given quantity of stom-
ach fluid, usually 100 cubic centimeters, it has been determined
that the normal amount of acid ranges from .180 to .200 grams.
This is indicated in the chart by the purple area, denoting that
a stomach containing this proportion of acid is normal in its
digestive power. Then the figures above and below the normal
area denote the relative proportion of excess or lack of acidity.
The column headed H denotes the amount of free hydrochloric
acid which has been found in the quantity of stomach fluid ex-
amined. It is calculated that the normal amount in 100 cubic
centimeters of stomach fluid ranges from .025 to .050 ; all quan-
tities above this amount are excessive, those below are insuffi-
cient for proper digestion. The column headed C denotes the
amount of combined chlorine; that headed A' indicates the
amount of free hydrochloric acid and combined chlorine taken
together. A' represents the quantity of work, without refer-
ence to quality, which the stomach does.

142 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Now, by referring to the two charts it can be seen that No.
8,938 possesses what may be called an acid stomach. Column A'
which denotes the working power of the stomach, shows that it is
excessive, which means that the food which is eaten is not like-
ly to be fully assimilated ; it is disposed of too rapidly. On
the other hand, No. 11,599 possesses a sub-acid stomach, where
the proteid digestion is defective ; the free hydrochloric acid is
seen to be especially lacking. In prescribing a diet for these
two individuals a physician would say that No. 8,938 should
abstain from acids in every form, while No. 11,599 is much
in need of acid that can be obtained in fruits. I happen to
know as a matter of act that if No. 8,938 drinks a glass of lem-
onade it will cause distress, while No. 11,599 is greatly benefited
by lemonade used very_ freely. The first subject cannot eat
sour apples with impunity, while the second subject is very
greatly benefited by their generous use. No. 8,938 likes foods
rich in proteids, probably because they are easily digested;
while No. 11,599 is not so fond of beans and similar foods con-
taining a large proportion of albumen. If No. 8,938 drinks
a glass of milk between meals he finds it difficult of digestion,
doubtless because the excessive acidulous condition of the stom-
ach causes coagulation of the casein before the digestive juices
can act upon it in a proper way. No. 11,599 does not apparently
experience inconvenience from a glass of milk at any time.

The analysis of stomach fluid reveals other digestive charac-
teristics than those already discussed. It will be seen by an
examination of the charts there is a column headed S in one
case and M in the other in which is represented the capacity
for starch digestion. This is determined by ascertaining the
percentage of maltose, expressed as dextrin, found present in the
stomach fluid. The normal amount in 100 cubic centimeters
ranges from 1.80 to 3.00. (The charts do not quite agree here,
due to the fact doubtless that the normal amount has been found
to be different as a result of more extended analyses. As the
analysis of No. 11,599 was made last, however, it is probable
that it represents more correctly the normal amounts, which

O'SHEA — ASPECTS OF MENTAL ECONOMY. 143

would then range from 1.80 to 2.50 grams.) Quantities above
or below these figures indicate a defect in digestive power.
While No. 11,599 is sub-normal in proteid digestion, he is hyper-
normal, if the term will be allowed, in starch digestion. No.
8,938 shows excess work here as in the case of proteid digestion.
As an outcome of these examinations it is possible to deter-
mine the working power of the stomach in various directions,
and the results are indicated in the charts by coefficients of di-
gestive work. It can be seen that No. 8,938 does excessive
work in respect of the liberation of chlorine during the digestive
processes, indicated by the tracing in the columns m and n.
No. 11,599 is quite deficient in this regard. The coefficient of
proteid digestion is a, and this power is shown to be normal
in the acid but deficient in the hypopeptic stomach.
The coefficient of fermentation is x, which is shown to exist in
the case of No. 11,599 but not in the other instance. The co-
efficients of starch digestion are of two kinds : b^ which denotes
the relation of the perfectly digested starch or maltose found
in the stomach fluid to the dextrin and soluble starch which is
imperfectly digested or converted; and b2, which has reference
to the amount of maltose or perfectly digested starch to the
amount found in normal digestion. No. 8,938 is sub-normal
in the first sort of digestion, and hyper-normal in the second;
and substantially the same condition is found in the other stom-
ach. The power of salivary activity is represented by the coeffi-
cient c. This is determined in the experiment by requiring the
subject to chew gum for a given length of timez the saliva se-
creted being collected and examined. The column headed y re-
lates to the digestive activity of the stomach with reference to
the power of disintegrating the food substances ; it is determined
by comparing the undissolved residue of the fluid with the to-
tal amount of stomach fluid obtained. In both stomachs there
is less than the normal amount, which shows excessive activity
in this respect. Finally the examination shows the rapidity
with which the stomach fluid is disposed of. The coefficient
2 refers to this digestive capacity, and is obtained by a comparir

144 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

eon of the amount of residual fluid found in the stomach at the
end of the first hour of digestion after a test meal with the nor-
mal amount It can be seen that in No. 8,938 the food is
hastened too rapidly, while in No. 11,599 absorption does not
proceed rapidly enough.

It must be apparent then that these differences in digestive
capacity advise somewhat different practices with respect to the
quantity and quality of foods eaten ; but the most marked dif-
ference between the stomachs is that relating to the digestion
of proteids, one individual needing to augment the natural sup-
ply of acid in order to promote the digestive process, while the
other* is embarrassed by the too bounteous gifts of nature.

OSHEA — ASPECTS OF MENTAL ECONOMY. 145

CHAPTER VII.

EXPENSE OF DIETARIES.

§1. Taste Versus Expense in the Choice of Foods. — In an
older day men lived to eat ; the gratification of the palate was
the sum/mum bonum of life. But the times have changed; life
is now seen to be more real and earnest and the table is not
its goal. But yet there are those among us who, while holding
to the higher and more spiritual ends of existence, still believe
that food should be chosen with reference to its taste, to its
aesthetic qualities, so to speak, rather than for its nutritive
properties. "Eat what you like,'1' these people say ; "this busi-
ness of seeing how you can get the greatest nutrition for the
least amount of money is unworthy cultured beings." Such
persons select their meats, their breads, and their wines prima-
rily because they are agreeable to the palate. Among some,
the choice of food upon this principle has developed into a fine
art. As great pains are taken in planning a bill-of-fare as in
painting a picture ; — there must be as great harmony of gusta-
tory sensations in the one as of visual sensations in the other.
The question of value for money expended does not enter into
the construction of a dietary at all with these neo-Epicureans.

Now, it seems to be a law of our being that what is indiffer-
ent, painful, or repugnant cannot exercise a beneficial influence
upon us ; that alone which is pleasureable seems to heighten the
tide of life. It is probable, too, that of all manner of obnox-
ious things distasteful food is the worst ; and so there is really
a show of reason in the doctrine, eat what you like. But upon
close examination it does not go very far ; it assumes that there
is incompatibility in deferring to the pocket-book and to the
palate at the same time. The conviction seems to be deeply
settled in many people's minds that what is nutritious is not
10

146 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

tasty ; and what is palatable may or may not have any nutritive
value, usually not. As a matter of fact, however, common sense
would suggest that what is best for the organism in the long
run affords the most agreeable gustatory sensations. The palate
never would have survived in the crisis of evolution if it had
not thus served the body faithfully. If in its pristine condi-
tion it selected foods which, while ministering to taste yet were
of little account in meeting the needs of existence, the race would
have disappeared in its infancy. Evolution, then, confirms
what unprejudiced observation and personal experience will tell
anyone, — that the most palatable foods fulfill the requirements
of perfect nutrition most satisfactorily.

§2. The Cost of a Dietary of Different Foods. — But however
the philosophy presented in the preceding section may be re-
garded by some, yet it will readily be granted by all that in
student life, as it is found in our community, the question of
securing nutrition at the least expense is a vital one. Consid-
erably over one-half of our students feel the need of economiz-
ing in every direction during their university career, and it
is probable that there is no place where wise economy would
be more effectual than in the arrangement of the dietary. This
may be accomplished, and I believe without doing violence in
any way to the legitimate rights of the palate. There are ap-
pended tables showing that the requirements of a perfect bill
of fare can be met with different foods at greatly varying ex-
penditures. To illustrate : If one had twenty-five cents to ex-
pend for food, it would purchase for him almost no nutrition
in oysters, for instance, but it would yield very large returns
if spent for bread, or oatmeal, or cornmeal, as the following fig-
ures show:

0 SHEA — ASPECTS OF MENTAL ECONOMY.

H7

Amounts of nutrients furnished for twenty-five cents in food mate'
rials at ordinary prices. (Atwater, op. cit., p. 28.)

Food Materials as
Purchased.

Beef, sirloin

Beef, sirloin

Beef, sirloin

Beef, sirloin

Beef, round

Beef, round

Beef, round .'.

Beef, neck

Beef, neck

Beef, neck

Mutton, leg

Mutton, leg

Mutton, leg

Ham, smoked

Ham, smoked

Salt pork

Salt pork

Salt pork

Cod, fresh

Cod, fresh

Cod, dry salt

Cod, dry salt

Mackerel, salt

Mackerel, salt

Oysters, 25 cents a qt
Oysters, 35 cents a qt
Oysters, 50 cents a qt
Eggs, 15 cents per doz
Eggs, 25 cents per doz
Eggs, 35 cents per doz

Price

per

pound ,

Cents.
10
15
20
25

8
12
16

4

6

8

8
14
20
10
16
10
14
18

6
10

6

8
10
15

12.5
17.5
25

8.8
14.7
20.6

25 Cents will Pay foe:

Nutrients.

Total
food
mate-
rials.

Total.

Pro-
tein.

Lbs.

Lbs.

Lbs.

2.50

.79

.38

1.67

.52

.25

1.25

.39

19

1.00

.31

.15

3.13

.95

.59

2.08

.63

.37

1.56

.47

.28

6.25

1.85

.98

4.17

1.23

.65

3.13

.93

.49

3.13

.96

.47

1.79

.55

.27

1.25

.38

.19

2.50

1.23

.37

1.56

.77

.23

2.50

3.09

.02

1.79

1.50

.02

1.39

1.16

.01

4 17

.45

.44

2.50

.27

.27

4.17

.63

.67

3.13

.51

.50

2.50

.74

.37

1.67

.49

.24

2.00

.24

.13

1.43

.17

.09

1.00

.12

.06

2.84

.63

.34

1.70

.37

.21

1.21

.27

.15

Fats.

Lbs.

.41
.27
.20
.16
.39
.26
.19
.87
.58
.44
.49
.28
.19
.86
.54
2.07
1.48
1.15
.01

.01
.01
.47
.25
.03
.02
.02
.29
.17
.12

Car-
bohy-
drates.

Lbs.

.08
.06
.04

Fuel
value.

Calo-
ries.

2,425

1,620

1,215

970

2,675

1,780

1,335

5,500

3,670

2,755

2,925

1,675

1,170

4,340

2,705

8,775

6,285

4,880

855

510

1,315

985

2.275

1,520

520

370

260

1,660

1,115

790

148

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Amounts of nutrients furnished for twenty-five cents in food mate-
rials at ordinary prices. — Continued.

Food Materials as
Pubchased.

Milk, 3 cents per qt

Milk, 6 cents per qt

Milk, 8 cents per qt

Cheese, whole milk

Cheese, whole milk

Cheese, whole milk

Cheese, skim milk

Cheese, skim milk

Cheese, skim milk

Butter

Butter

Butter

Sugar

Sugar

Wheat flour

Wheat flour

Wheat flour

Wheat bread

Wheat bread

Wheat bread

Corn meal

Corn meal

Oatmeal

Oatmeal

Bice

Bice

Beans

Potatoes, 45 cents per bush
Potatoes, 60 cents per bush
Potatoes, 90 cents per bush

Price

per

pound.

Cents.

1.5

3

4

12

15

18

6

8

10

15

25

35

5

7

2

2.5
3
3
5
8
2
3
3
5
5
8

0.75
9.75
1
1.5

25 Cents will Pat foe:

Nutrients.

Total
food
mate-
rials.

Lbs.
16.67
8.33
6.25
2.08
1.67
1.39
4.17
3.13
2.50
1.67
1.00
.71
5.00
3.57
12.50
10.00
8.33
8.33
5.00
3.1g
12.50
8.33
8.33
5.00
4.17
3.13
5.00
33.33
25.00
16.67

Total.

Lbs.
2.05
1.02
.77
1.36
1.09
.91
2.25
1.69
1.35
1.45
.86
.61
4.89
3.50
10.87
8.70
9.24
5.56
3.34
12.09
10.45
6.97
7.51
4.52
3.64
2.73
4.22
5.70
4.27
2.85

Pro-
tein.

Lbs.
.60
.30
.23
.59
.47
.39
1.60
1.20
.96
.02
.01
.01

Fats.

1.37

1.10
.91
.73
.44
.28

1.15
.77

1.22
.74
.31
.23

1.16
.60
.45
.30

Lbs.
.67
.23
.25
.74
.59
.49
.28
.21
.17

1.42
.85
.60

.14

.11
.03
.14
.08
.05
.47
.32
.59
.36
.02
.01
.10
.03
.02
.02

Car-
bohy-
drates

Lbs.

.78
.39
.29
.03
.03
.03
.37
.28
.22
.01

4.89
3.50
9.36
7.49
6.24
4.69
2.82
1.76
8.83
5.88
5.70
3.42
3.31
2.49
2.96
5.07
3.80
2.53

Fuel
value.

Calo-
ries.

5,420
2,705
2,030
4,305
3,455
2,875
4,860
3,645
2,910
6,035
3,615
2,565
9,100
6,495
20,565
16,450
13, 705
10,660
6,400
4,005
20,565
13, 705
15,370
9,225
6,795
5,100
8,075
10,665
8,000
5,335

O'SHEA — ASPECTS OF MENTAL ECONOMY. 149

§3. Local Expenses, With Practical Suggestions. — The aver-
age expense for table board in our community, as reported by
326 students, is $2.74. Some students pay $4.00, a few pay
$1.00, the majority come very near $2.50. This is about the
figure reached in the experiments made at the Maine State Agri-
cultural College.1 If abundant nutrition were obtained for
this amount, it would probably not be excessive; although it is
much greater than is necessary if a person finds it desirable
to economize rigidly. Atkinson2 has calculated bills-of-fare
which afford ample nutrition and give variety, but which do
not exceed in cost $.96 a week. Atwater's dietary lists at ex-
ceedingly moderate prices have already been given.3 At the
Battle Creek Sanitarium there are in the neighborhood of one
thousand helpers living very well on $.75 a week or less; and
there is no body of people to be met anywhere who appear bet-
ter nourished, or who manifest greater efficiency in body and
mind. It is certainly not overstating the case to say that our
students, regarded in the whole, could live very much better
than they do for the amount which they expend; and many of
them who deprive themselves of social advantages for pecuniary
reasons might a great deal better economize in their food with
profit to their pockets and their stomachs. Of course it is im-
possible in the majority of instances for a single person to inau-
gurate reform ; but where a hundred men are banded together
in a club, a little planning, a little intelligent study of the prob-
lems involved, such as they would expect to do if it were any
other matter under the sun, would be of tremendous advantage
to them. Perhaps the day may come some time when the man
who essays to manage a club or boarding house will bear some
credentials testamentary of his fitness for this business other
than that he is a "hustler," or is in need of money, or can
find nothing else to do.

If one were to suggest methods of economy, he would first
attack the meat which is found in students' dietaries, for this

1 Jordan, op. cit.

2Op. cit., pp. 175 et seq.

3 Chap. III.

150 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

is the most costly of all articles of food, as Jordan1 and
many another experimenter have found.2 It can be readily
seen that to raise wheat and corn and then feed them to cattle
must make the product more expensive than to use the grains
in their original form for human food. The process of passing
corn through cows and hogs before it reaches man involves time
and labor and waste which the consumer of flesh must pay for.
Paley3 wrote as follows upon this subject some time ago:

"In England, notwithstanding the produce of the soil has been con-
siderably increased by the enclosure of wastes, and the adoption, in
many places, of a more successful husbandry, yet we do not observe
a corresponding addition to the number of inhabitants, the reason of
which appears to me to be the more general consumption of animal
food amongst us. * * * If we measure the quantity of provision
by the number of human bodies it will support in due health and
vigor, this quantity, the extent and quality of the soil from which
It is raised being given, will depend greatly upon the kind. For in-
stance, a piece of ground capable of supplying animal food sufficient
for the subsistence of ten persons, would sustain at least the double
of that number with grain, roots, and milk."

Dr. Kichardson, in "Modern Thought" for July, 1880, devel-
ops this thought in an interesting way. He says:

"We really ought to consider the question of utilizing, on a large
scale, all vegetables which, in nutrient value, stand above animal
products. We have also to learn, as a first truth, the truth that the
oftener we go to the vegetable world for our food, the oftener we go
to the first, and, therefore, to the cheapest source of supply. The com-
monly accepted notion that when we eat animal flesh we are eating
food at its prime source cannot be too speedily dissipated, or too speed-
ily replaced by the knowledge that there is no primitive form of
food — albuminous, starchy, osseous — in the animal world itself, and
that all the processes of catching an inferior animal, or of breeding
it, rearing it, keeping it, dressing it, and selling it, mean no more nor
less than entirely additional expenditure throughout for bringing into
what we have been taught to consider an acceptable form of food
the veritable food which the animal itself found, without any such
preparation, in the vegetable world."

1Loc. cit.

2 See, for instance, Atwater, op. cit., p. 23 ; also Smith, quoted by Kingsford,
The Perfect Way of Diet, p. 103.

* Principles of Moral and Political Philosophy.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 151

Dr. Lyon Playfair, the well known English scientist, prose-
cuted a series of official investigations for several years on the
subject of military rations in England, Erance, Prussia, and
Austria. He found that in order to obtain the right amount
of albuminous matter it would be necessary to consume weekly :

Price (about)

s. d.

147 ounces of butchers meat 6 1

or 93 ounces of cheese 3

or 341 ounces of ordinary white bread 2 8

or 175 ounces of oatmeal 1

or 127 ounces of dried peas 1 2

In order to obtain the necessary proportion of dynamic or
caloric-forming substance, it would be necessary to consume
weekly :

Price (about)
s. d.

416 ounces of butcher's meat i7 4

or 224 ounces of cheese 7 °

or 298 ounces of ordinary bread 2

or 616 ounces of potatoes 2 9

or 221 ounces of dried peas 1 10

or 183 ounces of oatmeal 1 °

These figures, with others given on preceding pages, show
conclusively that meat is not an economical food from which to
obtain the energy required for either mental or physical labor.

Herbert Spencer, when considering some years ago the advis-
ability of living more largely upon a vegetable diet,1 complained
that it was impossible to get the requisite amount of albumen
without too much energy being expended in digestion. This
objection is assuredly an important one. It has already been
said that to overburden the system wi,th innutritious, indigesti-
ble and largely waste materials results in a limitation of its
efficiency ; and when the albuminoids cannot be easily obtained
in peas, beans, grains, and nuts the additional expense for meat
in student dietaries is certainly justified. But I maintain what
has already been urged, that right cooking and the freer use of
pulse and nut foods and grains, as cereals and breads, rich in

1 Education, p. 240.

152 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

albumen will give us this element in as digestible and concen-
trated form as can be obtained, in meat, and this will enable the
student to economize considerably in his dietary.

Another direction in which economy can be secured is in the
total abolition of pies, cakes, pickles, and the like. They really
serve no useful purpose in the dietary; nutritious foods will
minister to the appetite just as fully and will in addition recom-
pense the eater for his financial outlay.

o'SHEA A8PECTS OF MENTAL ECONOMY. 153

CHAPTER VIII.

FRESH AIR, EXERCISE AND REST IN THE PRODUCTION AND
EXPENDITURE OF CEREBRAL ENERGY.

§1. Function of Oxygen in {he Organism, — Many people
seem to think that albumen, fat, and carbohydrates are suffi-
cient in themselves to supply the organism with energy; if you
eat enough, they say. you will be vigorous enough in mind and
bodv. But a little reflection will teach one that fat and carbo-

1/

hydrates as such are only force in potentia, so to speak. They
are absolutely powerless in the system until they are oxydized,
so that an adequate supply of oxygen is as essential to proper
nutrition, in the broad sense, as a liberal quantity of carbohy-
drates and other substances. An organism deprived of a due
allowance of oxygen becomes lethargic; and if it be altogether
cut off, entire absence of action supervenes, a fact with which
everyone is of course familiar.

Now, observation and experiment have indicated somewhere
near the amount of oxygen which the human body requires for
greatest efficiency, and this must be secured by a constant ap-
portionment of air containing the "life giving element" in a
certain uniform proportion. In determining this proportion
the ratio of C02 to the other constituents of an atmosphere is
.usually taken as an index of the purity of that atmosphere,
since this gas is generally found in the presence of other gases
which, vitiate the air. It has been calculated that more than
4 parts of carbonic acid gas in 10,000 parts of air renders the
latter incapable of furnishing oxygen to the system in the re-
quired quantities.1 This estimate can be only relatively true,
however, since organisms differ respecting the amount of oxy-
gen which they need to support mental and bodily activities. A

1 For the results of investigations relating to this subject, see Burnham, Peda-
gogical Seminary, June, 1892, p. 23, et seq.

154 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

high-strung individual, as we say — one who is intense in thought
and quick and vigorous in physical movements — must needs
generate more vital force than a person of an opposite temper-
ament. Again, one possessing a relatively large inhalant sys-
tem can thrive in an atmosphere where a small-lunged unfortu-
nate would be able to do little more than keep body and soul
together.

But for the average individual it is essential in order that
he may obtain the necessary quota of oxygen that there should
be furnished him about 30 cubic feet of air per minute; and
this with the ordinary methods of ventilation will necessitate
about 225 cubic feet of space1 being set apart for his sole tenant-
age. These figures can only be suggestive, since the volume of
space demanded depends upon the rapidity with which the air
changes and upon its richness in oxygen. But taking these esti-
mates as of general trustworthiness, we find that the majority
of our students are fairly well circumstanced in respect of el-
bow room in their living quarters. In our questionnaire we
asked for the size of their apartments, with the number of per-
sons they contained, and the following table presents the results :

1 Martin (Human Physiology, p. 377) says that an individual should be sup-
plied with 800 cubic feet of space ; but it is probable that this is not at all es-
sential in properly ventilated apartments. Burnham, op. cit., summarizes the re-
sults of investigations upon this subject as follows : "According to M. de Chau-
mont, at the International Congress of Education at Brussels in 1880, Belgium
prescribed one square meter of floor-space and 4.5 cubic meters of air-space to
each scholar ; but the Educational League of Belgium, in the plans of its model
schools, proposed 1.67 sq. m. of floor-space and 9.6 cu. m. of air-space to each
pupil. In Holland the average per head was 4.54 cu. m. In England, in the
Board Schools, auout 1 sq. m. of floor-space and from 3.65 to 4.25 cu. m. of air-
space were allowed. Bavaria prescribed 3.9 cu. m. for scholars of eight years,
and 5.6 cu. m. for those of twelve years. In Sweden, in the primary schools 1.52
sq. m. and 5.35 to 7.55 cu. m. ; in the higher schools 2.17 sq. m. and 7.69 to
9.98 cu. m. per head were allowed. In Switzerland the regulations vary in dif-
ferent cities. In Berne a subcommittee of the Police Directors reported two or
three years ago in favor of 4 cu. m. per pupil under ten, 5.5 cu. m. for pupils
over ten ; in all cases 1 sq. m. of floor-space. In some schools as much as 6.50
cu. m. of air-space per child is required. In Austria 0.6 sq. m. and 3.8 to 4.5
cu. m. are required. In the country schools in Prussia a floor-area for each
pupil of at least 0.64 to 0.74 sq. m. and a height of 3.20 m. — therefore at least

2 to 2.37 cu. m. of air space — are provided. In the higher schools from 3.9 to
5.2 cu. m. are required. In Wurtemberg from 3 to 5 cu. m., in Hesse and Baden

3 cu. m. are prescribed for each pupil."

O'SHEA — ASPECTS OF MENTAL ECONOMY. 155

No. in room.

Smallest.

Largest.

1

9Yt x 9x8
12 x 15 x 9
10 x 12 x 8

16 x 14 x &

2

24 x 12 x 8

3

12 x 16 x 8

It is apparent at a glance that so far as breathing space alone
is concerned our students are on the whole well off. But the
method of heating determines in largest degree the oxygen value
of the atmosphere of any room which is much used. One heated
•by steam, with no provision for the entrance of fresh or the
exit of expired air, is quite certain to be improperly oxygenated,
be it ever so spacious ; and people living therein are likely to
experience sooner or later a decrease in their energies. About
one-third of our students reported that their rooms were heated
by steam, over one-half were favored with hot air; while fifty-
four were kept warm in the old-fashioned way, by coal and
wood stoves. It is probable that the most satisfactory method
of heating, regarded from the point of view from which we are
considering the subject, is by hot air, where the wholesomeness
of the atmosphere is more easily secured. On entering a house
in winter it is not difiicult to detect whether it is heated in
this or in some less hygienic manner. It may be added here
by way of exhortation that students occupying apartments
heated by steam or by stoves must give especial attention to ven-
tilation. And this is as necessary at night as during waking
hours ; for it seems, as Richards says,1 that during sleep the or-
ganism stores up oxygen which is to be utilized in generating
force for the activities of the following day.

The effect of inadequate ventilation is readily apparent in
lessened vigor of mind and body, and there can be no doubt that
mental acumen and endurance in some cases, and lethargy and
dullness in others, find their explanation in the quality of air
habitually inspired. It may be remarked in passing that this
subject needs attention from university authorities as well as
from students themselves. A class-room filled full of seekers

!The Northwestern Monthly, Vol. VIII, July, '97.

156 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

after knowledge, and which retains from day to day the respira-
tory contributions of its occupants, is, to say the least, a poor
mount on which to entertain the Muses. Libraries in which
the atmosphere is rarely changed furnish occasion for idle and
even stupid gazing at books; one cannot drink deeply at the
Pierian spring in such a place. Morrison1 has well said that
in a comfortable atmosphere of proper temperature and purity
as much labor can be accomplished in one hour as can be accom-
plished in six hours in an atmosphere rendered impure by respi-
ration.

*

§ 2. Exercise. — Doubtless every one is familiar with the most
important effects of physical exercise upon the somatic func-
tions. Hygiene has taught us these many years that muscular
activity quickens circulation, stimulates the organs of elimina-
tion, arouses lethargic cells in all parts of the body, creates
a need for oxygen which results in increased respiration ; and,
in short, produces a general feeling of euphoria, of well-being,
which must be of distinct advantage to the organism from what-
ever point of view it is regarded. That which heightens the
tide of life as a whole must be considered as fostering more
vigorous and efficient mentation ; so that if exercise produced
directly only physiological effects in the organism, it would
still be of inestimable benefit to the mind. But there are other
.ways in which it is of marked advantage to the mental life.
For one thing, it relieves muscular tensions which sap the vital-
ity of the physical medium of mind, a matter which will be
discussed at length later.2 The point which must receive
special attention here relates to the value of exercise in pro-
moting metabolism in the cerebral motor areas, and hence in
augmenting the total energy-producing capacities of the brain.
According to a now prevalent view of which Flechsig3 is the
most illustrious exponent, energy generated in one nerve cen-

1The Ventilation and Warming of School Buildings.
2 Chap. X.

sSee Gehim und Seele. See also Curtis: Inhibition, Pedagogical Seminary,
Vol. VI, No. 1 ; Burk. op. cit., and Newsholme, School hygiene, Chap. XII.

OSHEA — ASPECTS OF MENTAL ECONOMY. 157

ter may in a well organized brain be utilized in a different one;
thus I may be producing a large amount of force in the motor
areas of my brain but be employing it in the reflective, the
thought regions. If I exercise any certain parts of the cere-
brum more than others, energy tends to flow into them and
out of the unused areas. Cerebral energy may not inappro-
priately be likened to water in respect of its tendency to seek
a level ; if it be drawn out in one quarter, it will rush in
from others to preserve the equipoise. This theory, which is
in harmony with our knowledge of the structure of the cere-
brum as an instrument for the production and transmission
of energy, is also corroborated by the familiar experience of
inhibition in daily life. Every one must have observed that
when he thinks vigorously, the degree and force of physical
action is lessened; and, on the other hand, when the muscles
are most active the mind is relatively inert. Xow, it seems
to be a rational supposition that mental activity inhibits phys-
ical activity, because it draws away from the motor centers
energy required for muscular action. When the mathematical
part of the brain, for instance, is intensely active, we may con-
ceive that, energy from other localities sets in toward this as
a focus, and so activity in other regions is lessened; all is ex-
pended upon the particular undertaking in hand.

Now, if this theory be valid, an inference may be drawn
from it of vital significance in regard to the value of exercise
for brain workers. If the cerebral motor areas be maintained
in a vigorous condition ; if the metabolism of the cells be kept
at its best, that is to say, then the surplus energy generated
here may be utilized in intellectual labor. On the other hand,
one who does not use his muscles, who does not stimulute the
motor cells, fails to make use of great laboratories for the pro-
duction of vital force. A student who, desiring to accomplish
the most in his studies, denies himself all physical exercise
must, according to our theory, be a loser in the end. And in
more ways than one. He not only fails to keep in their prime
all the energy-generating powers of the brain, but he really

158 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

breaks up the unity between intellectual and motor activities
which seems to i be essential for the best mental health and
balance. A certain amount of motor activity is without doubt
necessary for the stability and integrity of mind, and this is
becoming more apparent every day as the pathological aspects
of psychology are being more carefully examined.1 On account
of this close relationship between mental and motor activity,
it is probable that at no time in life can one divorce them en-
tirely with safety to either mind or body.

The question respecting the amount of exercise which is
most suitable for students is a vital one. In the present state
of our knowledge it is impossible to give a definite answer to
this; about all that can be said now is that each person must
test the matter for himself, taking for his guide the principle
that his physical activities should serve the purpose of keeping
the organism in proper repair and furnishing energy to sustain
mental effort. In so far as it fails to do this, it must be regarded
as of little value, and it may be distinctly detrimental. If one's
experience in the gymnasium or out of doors lessens the capacity
for sustained mental effort, it shows that it is either excessive or
not adapted to the needs of the individual. If one will become
conscious of the matter for a time, he can doubtless make a rule
fairly well adapted to his peculiar necessities.

While it is probable that many students in our university
do not have exercise enough, yet it is certain that some have
too much for the best intellectual work. I have been able to ob-
serve with some care for one year the mental processes of one of
our athletes. During the fall he was under heavy training, and
throughout the whole of that period he was less keen, vigorous,
and sustained than usual in all of his intellectual labor. He
could not reason well, was not quick in apprehending a point,
was not ready in retaining or recalling what had apparently been
mastered from day to day. Two or three weeks after the ath-

1Ct. Seguin : The Treatment of Idiocy by the Physiological Method; cf. also
Wey, quoted by Hanciock, A Study of Motor Ability, Ped. Sem.. Vol. Ill, p. 24 ;
Burk, op. cit ; Oppenheiui, op. cit., chap. V.

O'SHEA ASPECTS OF MENTAL ECONOMY. 159

letic season had closed his mind brightened up considerably,
showing improvement in every direction. I conversed with
him frequently regarding his mental performances, and he was
conscious himself that undue physical exertion occurred at the
expense of intellectual acumen and vigor.

It may appear to some who read the above paragraph that
it conflicts with the popular belief that athletes make the best
scholars. I am inclined to think that an athletic student who
does not go beyond bounds in his training for contests is likely
to be superior in his mental tasks, since he has more energy
which can be employed in this direction if he will only reserve
it in right measure for that purpose. It is easy to see then why
a. good athlete should attain high rank in scholarship in the long
run, and at the same time do poor work while under training.
When he does give himself up fully to his studies, he can ac-
complish more than the general run of folks and so keeps up his
average; but if he continues in severe training throughout the
whole year, I think it is altogether unlikely that he will attain
fame in things of the mind.

Our students vary a good deal in the amount of exercise which
they take. Twenty say they spend one hour a day in the gym-
nasium, forty-eight spend two hours, and thirty-four spend three
hours. In many of the answers it was impossible to tell whether
exercise was taken every day or only on special days in the week.
A majority of our students reporting spend more time out of
doors than in the gymnasium. One hundred and thirty-three
spend about an hour a day out of doors, eighty-three spend two
hours, and forty-two are in the open air three hours a day. If
one should hazard an opinion upon the practices of our students,
he might say that those who take exercise systematically have
probably on the average enough to meet their needs. One hour
a day of quite vigorous exercise out of doors or in the gymna-
sium will probably, for the majority of individuals, serve to
stimulate beneficially all the organs of the body, to eliminate
waste materials, and to keep the motor centers in a healthy, ac-
tive condition.1

1cf., for instance, Newsholme, loc. cit.

160 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

The particular form of exercise "best suited to head workers
is a very important matter. Regarded from our point of view,
that kind of physical activity will be most efficient which keeps
the cerebral motor areas in best repair, and which involves the
least dissipation of vital forces. Now, it seems to be a principle
of our human nature that what we like to do is in general better
for us than the things we hate. Pleasurable activities create less
wear and tear1 than those which are distasteful, an arrangement
we should infer from the principles of evolution, even if we had
no confirmatory experience with it in our own lives. Disagree-
able tasks lie along the lines of greatest resistance for the organ-
ism, so a relatively larger amount of energy must be expended in
overcoming them; while on the other hand, what is agreeable
opens up ways of easy progress, and makes comparatively little
demands upon our powers. This doctrine is of vital conse-
quence in relation to our phye'eal exercise. Games and plays
and gymnastics which are pleasurable will accomplish the pur-
pose of recreation better than those which are indifferent or
bore-some. A game which will enlist our lively interest will do
much more for us than formal drill which we have to coerce
ourselves through. In other words, play, in the best sense of
the term, whether in the gymnasium or out of doors, constitutes
by all odds the most efficient method of exercise ; 2 it usually in-
volves the various organs of the body and utilizes highly co-ordi-
nated and complex activities, so that all parts of the motor mech-
anism of the brain are brought into action. "Man is wholly
man only when he plays," Schiller says. On the other hand,
formal drill ofttimes makes use of only a few movements and so
stimulates but small portions of the cerebral motor areas.

Again, so far as possible the will should be released in physi-
cal exercise. This is accomplished more largely in play than
in drill which one dislikes ; things which we hate we have to will

Jcf. Johnson : Education in plays and games; Ped. Sem., Vol. 3, pp. 98 and 99.

2 From the earliest times men have appreciated the transcendent value of play
in the development of childhood and youth. See, for instance, Plato, Laics, I,
643 and Rep. VII, 537 ; Aristotle, Bk. VII, 17 ; Froebel, Education of Man, § 30 ;
Locke in Quick*s Locke on Education, p. 55, 76.

O SHEA — ASPECTS OP MENTAL ECONOMY. 161

to overcome, while those activities which draw us spontaneously
do not require for their execution an act of volition. Observe
a boy at play and at work. The play may really be harder in
the sense that more work is done and more difficult movements
are performed, but yet his will is not exerting itself against ob-
stacles and so he is really less fatigued over the heavier than
the lighter task. Aud so it is with all of us ; we tire much more
readily in performing tasks in which we have no interest. Econ-
omy then demands that a student's physical exercises be gen-
uinely pleasurable; that he go to them without having to drive
Jiimself. Recreation will then accomplish the purpose for which
it is taken, rather than become an additional burden to an al-
ready overtaxed will-1

A word may be said before leaving this subject upon spe-
-cific sorts of exercise. Dancing is a very common form in our
community ; one hundred and sixty-seven of our students re-
ported that they danced, while one hundred and forty-eight did
not. The frequency with which dancing occurs differs much
with different students; many of the young women in Ladies'
Hall dance every night after the evening meal ; others dance once
a week or once in three weeks ; while a few dance once a semester.
The amount of dancing at any one time is, again, quite varied.
In Ladies' Hall it lasts for an hour in the evening. Two stu-
dents reported to have danced frequently until 5 o'clock in the
morning ; the majority of the others, however, ceased their pleas-
ures at 11 or 12 o'clock at night. It is not necessary here to pre-
sent arguments in favor of dancing as a beneficial form of exer-
cise ; from our point of view it answers well all the requirements,
especially when it is taken under conditions of good ventilation
and proper temperature. But too emphatic condemnation can-

*cf. the following: O'Shea, Physical Culture in the Public Schools: Atlantic
"Monthly, Feb., 1895 ; Groos : Die Spiele der Menschen, especially Zweite Abtheil-
ung, pp. 467-503 and 516-526 ; Hughes': Educational Value of Play, and The Re-
cent Play Movement in Germany ; Ed. Rev., Vol. XIII, pp. 327 et seq ; G. E.
Johnson ; op. cit., pp. 97 et seq. ; Earl of Meath ; Public Playgrounds for Chil-
dren ; 19th Cent. Vol. XXXIV, pp. 267 et seq. ; Gulick : Psychological, Pedagogi-
cal, and Religious Aspects of Group Games; Ped. Sem., Vol. XI, No. 2 ; and Some
Psychical Aspects of Muscular Exercises, Pop. Sci. Mo.. Vol. 53, pp. 793-805.

11

162 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

not be urged upon dancing until 12 o'clock at night once a week
or once in two weeks or at longer or shorter intervals. This
must be extreme for the average individual ; and, like all kinds,
of excess, it must result in a positive detriment to the organism.
While we have little data other than the testimony of experience
for this statement, jet I think most people will agree that danc-
ing for four hours produces fatigue, and that the individual is
rather the worse for his recreation. If dancing be practiced as
a form of business or of dissipation, that is one thing; if it is
indulged in for recreation and recuperation, that is an altogether
different thing. In order that recreation re-create it must re-
fresh and not overtax; it must leave the individual with more
of potency than he had when he started in, which cannot be the
case when one dances four or five hours continuously. If we
could only have dancing more frequently and for shorter pe-
riods, say twice a week lasting in no case beyond two hours, I
believe it would be a valuable form of recreation ; but it cannot
be so considered as it is now practiced by many in our midst.

Brain workers will probably be benefited more by activities
requiring the greater use of the fundamental than of the peri-
pheral muscles. Gymnastics and games then should not re-
quire too exact and delicate co-ordinations, since it would seem
that student life really demands enough of this sort of thing in
the prosecution of studies. The cerebral areas controlling the
peripheral muscles are doubtless involved in thinking, and it is
desirable that our recreation should relieve these areas from
active exercise while calling others into play. Again, it seems
to me especially desirable that our amusements should engage
the muscles principally rather than the- mind. Cards, checkers,
authors, and the like must be poorly suited to the needs of those
who use their heads constantly in their regular employments.
Whist is a study ; it probably dissipates as much energy as al-
gebra, and utilizes somewhat similar parts of the brain. A stu-
dent's life economically planned would aim to expend in study
all of the energies which should be devoted to intellectual activi-
ties, while recreation would involve motor activities almost
wholly. Billiards, for example, must be regarded as a very su-

O'SHEA — ASPECTS OF MENTAL ECONOMY. 163

perior sort of recreation for a student, compared with euchre.
Bowling is doubtless better still ; and in short all pastimes in the
gymnasium or out of doors that make the motor element promi-
nent, are to be commended above those which are principally in-
tellectual.

§3. Sleep. — In every living thing so far as we know periods
of repose alternate with periods of activity. There is a kind
of rhythm of action and of rest. Activity involves waste of liv-
ing substance and cessation of action is essential that recupera-
tion may take place. This rhythm is especially marked in hu-
man life. We have a long stretch, say sixteen hours, of waking
life, during which mind and body are active and energy is dis-
sipated ; then there supervenes a season of quiet, when worn out
tissue is repaired and the organism is brought back again to the
normal condition. This period of rest seems to be even more
important than nutrition for the preservation of life; for ex-
periments have been made upon dogs showing that death fol-
lowed more quickly from lack of sleep than from lack of food. 1

Hodges' studies2 demonstrating that in the case of animals
cerebral cells were depleted of their contents after a day's activi-
ties and restored during the quiescent period of the night are
suggestive respecting what in all probability takes place in prin-
ciple in the human brain. Waking life robs brain cells of their
substance ; then during sleep, when the mind is in repose, the
cells regain the energy which is essential for the sustenance of
activity. If a man be denied sleep so that the drain upon nerve
cells continues beyond a certain point, he will, of course, be
thrown into a condition of fatigue, when intellect and emotions
must suffer. It is then of vital consequence in student life that
periods of activity and rest be so alternated as to keep the nervous
organism in the best possible repair.

Now, it has not been determined by exact experiment, so far
as I know, just how much sleep an individual needs. In all
probability this differs with different people. There have been
great historical personages, for instance, who have been able

*I have lost my authority for this statement, but I remember clearly the ex-
periments and the outcome.
2Loc. cit.

164 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

while guiding the destinies of nations to survive o.n a very lim-
ited amount of sleep. Every one knows of Napoleon's capacity
in this direction. On the other hand, Gladstone is said to have
required seven hours' sleep quite regularly throughout his public
life. In our own country there is a president of a great uni-
versity who is reported to get along with at most four hours of
sleep, and on occasions he is able to do well on two hours. But
for the majority of individuals it is probable that somewhere
near eight hours is essential.1 Cowles,2 Beard,3 Mills,4 and
other writers upon nervous exhaustion are quite insistent upon
this amount for all people; and while it may certainly be im-
possible for one individual to survive on what another will thrive
on, yet it is probable that a third of the day spent in sleep could
not but be of advantage to every person and in no case could
it be a detriment.

The majority of our students give the required number of houra
to sleep. Two hundred and thirteen reported that they devoted
eight hours to this purpose ; fifty-eight spend seven hours ; thirty-
four, nine hours ; one, ten hours ; four, six hours ; while only two
spend five hours. If their sleep be sound then our students
should on the whole be well provided for in this respect. But
in many cases people feel they are complying with all the re-
quirements if they simply lie in bed. However, in order that
sleep be fully reparative it ought to be peaceful and dreamless ;
otherwise the cerebral areas concerned in conscious mental life
are active and energy is being dissipated. That one may secure
this perfect rest his sleeping environment must be quite -free
from noise. Noise has a peculiar effect upon one asleep ; even
the slightest auditory stimulus seems to produce a waking re-
action. It appears that there is in the human soul a sort of
memory of earlier racial experiences where noise was a most
significant affair; an animal that could not awaken instantly
upon sounds of howling or cracking or crunching or breathing

lcf. Kotelmann, School Hygiene, pp. 187 and 225-231.
*op. cit.
*op. cit.

4 Mental Over-work and Premature Disease Among Public Men. Smithsonian
Inst., Lower Lectures, No. IX.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

1G5

in his vicinity would have little chance of escaping from ene-
mies lurking everywhere. And now, although man is quite safe
in an environment of any amount of racket, yet he has not fully
outgrown this old racial tendency to awareness in the presence of
noise. It is instructive in this connection to observe a little
child who in the earliest weeks trembles with fright at a loud
noise, and cannot sleep except in an atmosphere of quiet.

The effect of noise upon a sleeping subject has been studied
by Lombard and others,1 and the results are conclusive in show-
ing that even a slight disturbance causes a decrease in peripheral
blood supply, indicating that the blood is flowing in increasing
quantities toward the brain which tends to return to the waking
state. The charts which follow show this phenomenon.

1

\

„..>•■■—■, v»

\

'I,

'"ini.i'i'1"1

II"

y

i<i<fiii

'.^lll,„ll'•»"',,"",

m —

.u

,<"'

ig. 11. Plethysmography record from the arm of a person sleeping in the lab-
oratory. A fall in the curve indicates a decrease in the volume of the arm. The
curve is to be read in the direction of the arrow. 1, the night watchman en-
tering the laboratory ; 2, the watchman spoke ; 3, watchman went out. These
changes occurred without waking the subject. (Donaldson, op. cit., p. 289.)

Illllll'1

[1

!

1

III

ll

Fig. 12. — Record similar to that above. Change in the volume of the arm of
Sleeping subject, caused by the sound of a music box which was started at ••
(Donaldson, loc. cit.)

The importance then of quiet while one is asleep cannot be too
greatly emphasized. There should be a "rest" law in every
house where students room, enacting that after a certain reason-
able hour absolute quiet shall prevail. Certain it is, at any rate,

JSee for instance, Angell and Thompson, op. cit., for a summary of results of
investigations.

166

BULLETIN OF THE UNIVERSITY OP WISCONSIN.

that one whose sleep is not undisturbed will manifest the out-
come in a lessened amount of vigor which may be utilized in in-
tellectual work.

Some of our students preparing for examinations deprive
themselves of sleep altogether for three or four nights. That
this is a serious mistake hardly needs argument, it seems to me.
It is probably not only a waste of energy in the long run, but
really defeats the purpose for which the individual remains
awake; for when the mind has been driven twenty-four hours
without relaxation, it is not in a condition to do vigorous think-
ing; and if the strain be kept up throughout an entire exami-
nation week, the intellect must suffer in all its operations, — per-
ception, memory, reason, and the rest. Some experiments have
been made by Patrick1 respecting the effect of prolonged absence
of sleep upon muscular and intellectual capabilities, and these
should be of interest to those students who study all night pre-
paratory to an examination. The charts which follow indicate
the increasing uncertainty in and diminution of various mental
and physical powers as the period of constant waking life length-
ens.

IPM

Fig. 13. — The ordinates show the number of seconds required to add a given
number of figures. The abscissae show the progress of the hours during the wak-
ing period. The last interval, however, representing the period of sleep following.
(Patrick.)

*At the University of Iowa. See Studies from the Psychological Laboratory of
the University of Iowa, Vol. I.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

167

3*

6A 3P 2>" 3 A <SA 3r Sr 3* SP SP t>P 3A 9A 3f» 3>»

Fig. 14. — The ordinates show the relative intensities of sound required for dis-
crimination. The abscissae show the progress of the hour as explained above
< Patrick.)

.9o3A

180

3P 3A 3A 3P 3P 3A 9/K 3P 9P 3A 9A 3P 3P ^PM

Fig. 15. — The ordinates show the number of letters named in one minute. The
abscissae show the progress of the hours as explained above. (Patrick.)

168

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

9a jp 5P ;
I80r

A 3A 3P 9P >IA SA 3F 3P »A 9A 3P 9P

IPM

Fig. 16. — The ordinates show the number of letters named in one minute. The
abscissae show the progress of the hours as explained above. (Patrick.)

Ch///7afefi» //ft in fa/&s.
Afac/ssete** /progress cf boors

160

-VPrt

5AM 3P S>P 3A 3A 3P 6f 3A 2>A 3P S>P 3A 3a 3p 3P I Pfl

Fig. 15. — The ordinates show the strength of lift in kilograms. The abscissae
ebow the progress of the hours as explained above. (Patrick.)

O SHEA — ASPECTS OF MENTAL ECONOMY.

169

Ore// nates = no of seconds fomemcr/je /6 attaife

90 c3^ ;

5P SP 3*> 3a a

P .s

p v. 3/^ ^

'p sp 2** e>/^ 2

p ;

>p

-f/vy

8oc

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fcOc

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,*/<?>

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1

V

1

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£00

/

s

\

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<£.A

'•&.

/

\

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A

/

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t

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Fig. 16. — The ordinates show the number of seconds required to commit to
memory 18 digits. The abscissae show the progress of the hours as explained
above. (Patrick.)

It is probable, to add a last word, that a student who studies
hard for say eight or ten hours has accomplished all that can be
done with profit or with safety without a long period of sound
sleep. Memory and reason will be more faithful and accurate
the following day if the mind be thus refreshed than if it be
driven on beyond the point of normal fatigue. And then when
exhaustion is reached it requires such a relatively long time
for recovery.1 In normal fatigue a night's rest should bring
complete restoration ; but there is a point beyond this where the
cell seems to lose the power of ready recuperation and it takes
the spendthrift a long time to get back to himself, so to speak.

JSee Hodge, op. cit.

170 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

CHAPTER IX.

THE CONSERVATION OF ENERGY.

§1. Wasteful Muscular Tensions. — It is recognized in me-
chanics that a large part of the energy expended in the working
of a machine is wasted ; a relatively small amount, say 25$, in
the best machines is devoted to accomplishing the purposes for
which the machine exists. The more perfectly a machine can
be constructed so as to save this fruitless expenditure of force
the more efficient it becomes, of course ; and so it is of vital con-
sequence that friction and other avenues of waste be blocked up
as fully >as possible. !STow the human organism is a sort of ma-
chine ; it has work to accomplish and a given quota of energy
which may be drawn upon' for this purpose. It is a truism
that the greater the amount wasted the less can be expended
in profitable production. But if one should maintain that this
body of ours has been so carefully fashioned that there can be
no loss of vital force, that all parts run together so smoothly and
co-ordinate so perfectly that every item of expense is in lieu of
value received, he would doubtless have a show of reason on his
side. It would certainly be a fortunate arrangement if this
most intricate of all mechanisms could run of it&elf without su-
perintending and with no loss or unnecessary outlay of vital
force; but I think we shall see that with the majority of us
there are frictions which can be at least reduced by a little de-
liberate planning.

The greatest source of waste of neural energy is found in
muscular tensions which are not at all essential to the accomp-
lishment of the piece of work in hand. This is seen to be true
in view of a simple physiological law, — that the exercise of a
muscle involves stimulation from nerve centers. This stimu-
lation implies a drain upon nerve cells, — an expenditure of en-
ergy, that is to say. When any task, as writing, is to be un-

O'SHEA — ASPECTS OF MENTAL ECONOMY. 171

•dertaken, then economy demands that no muscles be active ex-
cept such as contribute to the accomplishment of the work. But
suppose that the hand not employed is clinched, the lips are
compressed, deep furrows crease the forehead, and the fingers
controlling the writing are unduly tense, — in such a case a large
amount of effort is proving fruitless. The unnecessary con-
straints of muscles are simply draining the organism of energy
that should be conserved and expended in profitable directions.
Xow, there are certain practices in student life, as in the lives
of ]>eople in general, which entail waste of vital forces and
which can be modified without inducing too great self-conscious-
ness. In the first place mental tension readily begets muscular
tension. When the mind is perplexed ; when it discerns obsta-
cles ahead that seem insuperable; when conscience is incessantly
active censuring one for past deeds and exhorting him to be es-
pecially careful in the future ; when life seems full of cares that
demand unceasing attention, — such a condition of mind pro-
duces constraints of muscles which sap the organism of its vitali-
ties. When the attention is centered upon threatening difficul-
ties the body unconsciously takes on an attitude of defense, as
it were ; or, to be more precise, the organism seeks to adapt itself
to a mental situation and when we are troubled in mind our mus-
cles get ready to annihilate the causer of our trouble, or to re-
move us therefrom.1 One may see on our campus every day
students with set faces, so to speak; there are deep lines between
the eyes, there is a strain about the mouth, and the entire body
shows rigidity and tension. When you talk with such students
you can observe these abnormal "nerve-signs" in all the sensi-
tive muscles of face, hands, and body generally. Such people
are what might not inappropriately be called exhaustives ; they
are all the time drawing upon their bank deposits too heavily.
Outlay commonly exceeds income, or at least there is no large
balance on the credit side of the account. These are the over-
conscientious individuals ; thev can never do anvthino- without

1Cf. Angell and Thompson, Psychological Review, Jan., 1899, p. 69. See also
Darwin : Expression of the Emotions in Man and Animals for a discussion of the
general principle involved. Baldwin : Mental Dci-clopment, Methods and Pro-
cesses, Chap. VIII, treats of the subject in a readable way.

172 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

worrying about it before and afterwards ; they are troubled lest
they have not done or will not do just the right thing. They
belong to what Ribot would call the egoistic-introspective type ;
they cannot get away from themselves, and hence are constrained
and tense in most of their activities. It seems to be a law of
our human nature that turning the mind upon self throws the
machinery out of gear. Too much reviewing of conscience ; toe-
much hunting after one's faults ends in conscience being a very
ineffective guide in life. Its mandates cannot be carried into
effect by a weakened organism.

So much has been said in recent vears about "Americanitis'r
that it may just be mentioned in this connection. It is main-
tained that our American people do not know how to rest ; which
means, I think, that they make a great deal more fuss about do-
ing a thing than is necessary. Their actions are greatly in excess
of that which the occasion demands. When they do things that
should employ the hands only, they use the whole body; they
scowl and grit their teeth, and in other ways drain off their
forces. Dr. Clouston, the eminent Scotch authority upon ner-
vous diseases, visited our country some time ago and is reported
by James1 to have said: "You Americans wear too much ex-
pression upon your faces. You are living like an army with all
its reserves engaged in action. The duller countenances of the
British population betoken a better scheme of life. They sug-
gest stores of reserved nervous force to fall back upon, if any
occasion should arise that requires it. This excitability, this
presence at all times of power not used, I regard as the greatest
safeguard of our English people. The other thing in you gives
me a sense of insecurity, and you ought somehow to tone your-
selves down. You really do carry too much expression, you take
too intensely the trivial moments of life."

It is a vitally important matter in student life to acquire the
habit of adjusting effort to the task to be accomplished. When
great tasks are to be performed our forces must all be summoned
to the fore; but it is certainly bad economy to expend as much

1 Seribner's Magazine, April, 1899, p. 502.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 173

on trifling as on momentous occasions. But how can we release
these wasteful tensions ? Manifestly the first requisite is to al-
leviate the mental attitude which produces them. To many it
may seem heretical, but yet it seems to me true that there is too
much examination of conscience, too much thinking about self
in our American life. One who keeps his errors constantly be-
fore his mind's eye pursues the very best course for dissipating
his forces. One cannot be looking all J he time upon his own
shortcomings without strain and stress of mind and body in the
effort to overcome them. And, unfortunately, the more he
thinks of them the more securely do they fasten themselves
upon him. He rises above his lower self mainly by filling his
mind with ideals outside of himself, so that he may grow up
toward them. This is the only way, too, in which the machinery
of life can be got to run smoothly; which fact is evidenced con-
stantly among the people we meet in daily life. You see here
a person who lives an outward life. She thinks little relatively
of self, does not question unendingly whether What she does is
just right and proper, whether she ought not to have done some-
thing else, whether other people's actions are intended to injure
her. Her mind is full of worthy generous ends to be attained.
Then observe her physical expressions : no scowling except when
there is occasion for it; no rigidity of features, no constraint
and formality of bearing. Rather she is free and unconstrained
in all her activities ; the delicate mechanisms of her being work
together harmoniously and energy is expended only when work
is to be accomplished. Much egoistic-introspective thinking
seems to irritate the nervous system, unloosing forces which
should be securely held until their services can be profitably
utilized.1

While bodily relaxation is secured primarily through mental
poise, still something may be accomplished by voluntarily striv-

lWe are coming to see that too great self-consciousness is a disease breeder.
Faith cure, divine healing, and all the rest accomplish their good work by get-
ting the mind of an individual off from himself. The literature of the subject is
very extensive ; but for an interesting study and resume of important investiga-
tions, see Goddard : The Effects of Mind on Body as Evidenced by Faith Cures ;
American Journal of Psychology, April, 1899.

174 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

ing to let go of one's self. There is a good bit of sense in the
Delsartean philosophy,1 which holds, first, that the most vigorous
individuals in intellect and character are those who are freest
and most unconstrained in peripheral activities; and, second,
that by proper exercises wTe may cultivate the power of "holding
centers firm and releasing extremities." The Delsartean phys-
ical culture really helps "bottled lightning" people to take them-
selves less seriously. There are so many persons who, even when
they rest, as they say, sit with clinched fists and rigid body, thus
keeping up incessant drain on the nervous system. Let one who
is conscious of tenseness in his muscles voluntarily relax at cer-
tain times of the day as a matter of discipline. This will assist
in relieving the brain, and in time he will find himself relaxing
unconsciously. He will find, too, that his mental briar-patch will
not seem quite so thorny ; he will occupy a less prominent place
in his own reflections : for as mind influences body, so body in-
fluences mind.2 Voluntarily assume an attitude and it will
tend to awaken the emotion which usually initiates that attitude.
Take on the bodily counterparts of fear and fear is easily en-
gendered; while, if you stand bravely against the world, cour-
age will be strengthened. So one who consciously puts himself
into postures of rest and repose will go a good way toward se-
curing mental quietude. As when the mind is worried it keeps
the body aroused to ward off threatened dangers, or to accom-
plish visionary tasks ; so let the body take an attitude of repose
which is bred of confidence and trust that all is well with the
world, and the mind will easily follow in its lead.

Wasteful muscular tensions are begotten by other agencies
than a restless, worried, over-scrupulous mind. The implements
we employ in our daily tasks are responsible for much useless
drain upon the nervous system, — such apparently simple and
harmless things as writing pens, pencils, and the like. To ap-

JFor an interesting presentation of this philosophy, see Annie Payson Call r
Power through Repor.c ; and Emily Bishop: Americanized Delsarte. See also
O'Shea: Physical Training in the Public Schools, loc. clt.

2cf. Lee and Thomson: Beauty and Ugliness; Contempt. Rev. vol. 72; James:
Psychology, Briefer Course, p. 383. Baldwin, op. cit., p. 231, et. seq.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 175

preciate the principle here involved one needs to recall what has
been said respecting the hierarchal character of the cerebral
mechanism. It is needful to remember especially that the
"highest" brain centers exercise a general control over more fun-
damental ones and are charged with the management of the peri-
pheral muscular activities. Now, it seems to be true, although
it has not yet been so proven by extensive experimentation that
co-ordination of the peripheral muscles involves a relatively
larger expenditure of energy than coarser, less delicately ad-
justed movements. Thus fine needle-work is more fatiguing to
most women than washing dishes, and "getting pigs out of
clover'' is a much greater strain on any man than playing golf
or croquet. It is a rational inference, it seems to me, from the
known methods of cerebral action that in the majority of people
much activity of the third-level cerebral areas, those governing
peripheral muscles, results in the setting free of a larger quan-
tum of energy than is required to perform the work in hand.
Peripheral muscles as they are found in the human organism
have appeared relatively late in the development of the race, and
the nerve centers controlling them are not yet seemingly, for
most people, quite stable. Paths for the discharge of nerve force
have not become deeply grooved so that much overflows into by-
channels, as it were. On the other hand the fundamental bodily
actions have become so habitual that they do not apparently
lead to waste ; the neural avenues controlling them have become
so fully established that energy generated issues in profitable
production for the most part.

The position here taken is by no means fully warranted by
experimental evidence, and there are those scientists who feel
that through habit the individual may get to be as economical
in the use of peripheral as of fundamental muscles. My own
observations, however, lead me to believe that in the majority
of cases these conserving habits never become established in most
of us. I was able several years ago to gain something relating
to this point from the experience of a distinguished physician
in Buffalo, a specialist in diseases of the nose and throat. Some
of his work involved very delicate operations requiring most ac-

176 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

curate co-ordinations of the fingers. He said to me frequently
that he never undertook such cases except in the morning hours
when he was at his best; and after a relatively short period he
generally was greatly fatigued, so that he felt it necessary to
secure rest before continuing with his duties. On the other
hand, a half day's work in his general practice which did not
involve such exact co-ordinations would not overtax him. In
my own case, writing with a fine pen, which must be handled
tenderly in order to avoid catastrophes, soon exhausts my store
of energy and of patience; and I foimd during the past year,
while experimenting with writing pens, that an assistant and a
member of my own family had experiences similar to my own.

This phenomenon is especially apparent in the case of younger
people. Put a child of eight or nine to writing with a fine
pointed pen and in a short time you will observe tensions in
various parts of the body not employed <in the writing. Soon
the tongue will be extended, the hand not engaged will become
clinched, the head will begin to keep time with the arm; the
whole showing plainly to my mind that the co-ordinations de-
manded in the writing have liberated energy which is escaping
into channels which should have been closed up. On the other
hand, permit such a pupil to write with chalk at the blackboard
and he will continue for hours without apparent over-strain.
One who has opportunity to study developing children in the
home will be impressed with this wastefulness of too co-ordinated
activities.1 It is recognized, of course, that with the develop-
ment of the nervous organism greater delicacy and complexity
of co-ordinations are possible with less of waste; but yet I be-
lieve that at no time does the average individual reach a point
where he can economically practice the most exact adjustments
where coarser ones would answer just as well.2

This leads to a few practical suggestions respecting some of
the implements which are used extensively in student life. And
first the writing pen. Many of our students write a great deal,

xSee O'Shea: When Character Is Formed, Popular Science Monthly, Sept.,
1899.

*Cf. Hancock : A Study of Motor Ability ; Ped. Sem., Vol. 3, pp. 9-29.

O'BHEA — ASPECTS OF MENTAL ECONOMY. 177

some reporting six hours of written work a day. But this is ex-
treme; the average is about two and one-half hours daily.
Ninety-nine reported using fine pointed pens, while sixty-seven
used medium pens, and one hundred and eleven used blunt
points. It would be interesting to know whether those students
who employ fine pens and do much writing are able to prosecute
their work without fatigue ; but in lieu of data upon the subject,
the opinion may be hazarded that a medium or coarse pointed
pen would be the means of conserving energy for the great ma-
jority of students, not excepting those who have formed the
habit of using a very fine point. To repeat, though, this sub-
ject needs more extensive investigation before one may dogma-
tize upon it.

Believing that the matter of writing pens is a most important
one for students, I have during the past two years made a test
of all the pens I could secure from American manufacturers
with a view to ascertaining their energetic effects upon myself
and my assistant. While doubtless I have not had opportunity
to examine all the good pens made, I yet feel that of those com-
monly in use the one of medium point requiring the least waste
of energy in needless tensions is the Gillott No. 1065. It has
been my experience, however, that the ordinary gold pens are
far more satisfactory than those made of steel, since the point
moves over the paper more smoothly, requiring less delicate
management from the penman. I have been able to examine a
number of fountain pens and have found the Waterman Ideal
worthy of its name. Nos. 12 to 16, medium points, are well
adapted to conserve the energies of the penman, as well as to gain
time in writing, and they can not be too highly commended. I
have also found the Parker Jointless No. 023 to be a very satis-
factory pen from the point of view from which we are here dis-
cussing pens. I can write much longer and with less fatigue
with these fountain pens than with any steel pen, and those who
have assisted me in the experiments have had a similar experi-
ence.

"Scratchy" pens cannot be too severely condemned. Aside
from their irritating influence iipon the nervous system, they
12

178 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

require such careful handling that waste of energy cannot be
obviated. I have never known a person to write long with such
an implement without manifesting fatigue in body and mind.
Students who employ such articles to save expense or time in
securing something better belong to the penny-wise and .pound-
foolish fraternity.

Another most important characteristic in a writing pen is the
material of which the tip or holder is made. Metal holders are
very common, although fortunately only about six per cent, of
our students employ them ; the others use either rubber or wood
holders, or fountain pens. It may perhaps be worth saying for
the benefit of the benighted six per cent, that they have adopted
a most efficient plan for wasting their vitalities. When the
fingers grasp a metal surface perspiration accumulates quickly,
and if it be round it will tend to roll in the fingers. In order
to keep it in proper position there must be increasing tension
which, as any one may by trial prove to his own satisfaction, is
a potent agency in dissipating energy. Let one who uses such a
pen-holder exchange it for another with a cork tip, where the
moisture from the fingers is readily absorbed, and he will find
that too great emphasis has not been laid upon this apparently
trivial matter. The principle involved applies as well to lead
pencils ; those with highly glazed surfaces are difficult to keep
steadily in the right position without undue constraint of the
fingers. The Eagle Pencil Company is now manufacturing a
pencil answering the requirements in this regard. The Eagle
Cortex No. 2 has a surface of cork, and I have never known a
person to try it without commending it because of the ease with
which it may be managed. It may be criticised in one respect
only, that the lead is a trifle too hard for the greatest economy in
nerve force.1 A hard lead pencil, like a fine pointed pen, de-
mands relatively great co-ordinations and tensions in its control,
and hence leads to waste of force.

Three years ago a change was made from hard to soft lead
pencils in the Franklin School, in Buffalo, and the children were

*A8 this is passing through the press the Eagle Pencil Company sends me a
pencil with cork covering and soft lead, which meets the requirements indicated
herein.

O'SHEA — A8PKCT8 OF MENTAL ECONOMY. 179

unanimous in their praise of the softer variety. "They are so
much pleasanter to use" was the general testimony. I have ex-
amined most of the pencils of American manufacturers, I be-
lieve, and have found the Eagle Draughting to be the most satis-
f actorv. Our students are not so wise in their choice of pencils
as of pens. About seventeen per cent of those reporting use
hard pencils, while thirty-two per cent, use a medium quality.
The engineers use a hard pencil almost altogether, and this is
doubtless necessitated by the character of their work.

Needless muscular stimulations wherever they occur must be
regarded as dissipating vital forces. Thievery of the most seri-
ous kind is constantly taking place. This is especially signifi-
cant in respect of the eyes. One who has reflected upon it can
not but be impressed with the marvellous delicacy required in
the proper control of the visual organs. During waking life
they are incessantly changing position so as to bring objects
within the range of vision. In order to accomplish this they
must be equipped with ocular muscles1 so arranged as to secure
movements in all directions within a given orbit.2 In the nor-
mal eye these muscles are exactly balanced in their pulling ca-
pacities and are never active except when the interests of vision
require action. But now it happens in frequent instances, so
frequent as to be alarming in these last few years when investi-
gations have been made so extensively, that one of the muscles
moving an eye may be more energetic than its fellows. Or
through some error in the functioning of the reflex nervous
mechanism it may be active when it ought to be at rest. It tends
then to pull the eye out of focus, which would render vision dou-
ble if it had its way ; but the will seeks to avert this calamity
and so must stimulate a muscle opposed to the overacting one
so as to neutralize its effect. This results then in incessant mus-
cular strain which is a source of constant waste of vital forces.

Again, in the normal eye the lens and eye-ball are so con-
.structed that the focus falls exactly upon the retina. But now

lfThe four recti and the two oblique muscles.

= See Le Conte, Sight, Chapters 2 and 3, for a good discussion of the muscular
mechanism of the eye and the philosophy of defects. See also Cohn, Hygiene of
the Eye, Chapters 1-8.

180 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

it occurs more frequently than not it seems that this fine ad-
justment is not secured. The lens has not the right degree of
curvature as a whole, or in certain angles, or the eye-ball is either
too short or too long, wrhen the focus falls in front of or behind
the retina, or is not the same at every angle. The mind tries
to remedy any error of this sort by modifying the lens through
the delicate ciliary muscles. In a defective eye this stimulation
must go on incessantly, and one can easily imagine its effect in
draining the organism of its vitality. Every one has heard in
these recent years that the eye is the source of all disease ; and
while this is doubtless an exaggeration, it yet emphasizes a cer-
tain truth of vital importance to every individual, but especially
to the student in whom defective vision entails most serious con-
sequences, alike in blocking one important approach to the mind
and in robbing the system of its energy.1 In the defective eye
these muscular tensions go on hour after hour, and only the most
hardy constitution can endure the strain. This is evidenced in
a striking way in the sudden increase in eye defects during
adolescence. A great many boys and girls realize that they have
eyes at this time.2 The organism is now devoting its strength
to the building of heart and lungs and bones and cannot expend
so much in disciplining refractory eyes, when their baneful ef-
fects become apparent. So, too, in sickness people are conscious
of eye strain that they have not noticed before and which they
are never really conscious of except when the energies of the
organism are at a low ebb. Swift3 observed this phenomenon
frequently in his study of vision in the Normal School at Ste-
vens Point, Wis. He says:

"An interesting fact, though by no means a new one, was repeatedly
observed. Young boys and girls with more defect than some older ones
had never experienced any trouble with their eyes, while the older ones,
with much less defect, were constantly annoyed by eye ache or the blur-
ring of the letters. The difference was that the vigorous nervous sys-
tem of the young boys and girls was able to sustain the irritation of
the poorly constructed eye and, by an over supply of nerve force, could

JSee for an excellent discussion of this subject : James, Suggestions to Teachers
Regarding Visual Defects of School Children, Mankato, Minn. AI60 Ranney, la
New York Medical Journal, June 11, 1892.

'See, Some Adolescence Reminiscences, O'Shea, Journal of Pedagogy, Oct., 1898.

•Pedagogical Seminary, October, 1897, and reprint.

O'SHEA A8PECT8 OF MENTAL ECONOMY. 181

compel the eye to do its work without apparent injury, while the more
exhausted nerve centers of the young men and women could not stand
the constant call for more energy. 'Disease is localized abnormal in-
nervation and always central in the nervous system, being a lack of
excess of motive force.' It should not be forgotten, however, that eye
strain is a potent factor in this disturbance of the nerve centers."

One observing students on the campus of our University is
impressed with, the number who are not spectacled. Whatever
opinion he may hold regarding the relation of spectacles to men-
tal attainment he must at least conclude that many students are
wasting energy in combating visual defects that ought to be rem-
edied by glasses. Investigations made within the last decade
in various parts of our own country and Europe1 show that on
the average at least 30 per cent, of individuals have defects
of vision which require correction by lenses. And the defects
increase with age; as high as 40 or 50 per cent, of the children
in the upper grades in some places have defective sight. Ac-
cording to Sherzer : 2

"An examination of the eyes of over 5,000 school children and stu-
dents in Germany, France, Russia, England, and the United States, has
shown that as we pass from the lower to the higher grades there is a
gradual increase in the number of cases of myopia and in the degree of
the defect. The German government in a recent examination found
that in the elementary schools from 5 to 11 per cent, of the children are
afflicted; in the higher schools for girls, 10 to 24 per cent.; in the Real
Schulen from 20 to 40 per cent.; in the Gymnasia from 30 to 50 per
cent.; while in the universities the percentage may run up to 88."

According to Cohn3 myopia increases rapidly with age in the
German schools; "in the real schools the myopia percentages
from the sexta to the prima were 9, 16.7, 19.2, 25.1, 26.4, 44 ; in
the gymnasia 12.5, 18.2, 23.7, 31, 41.3, 55.8." Professor
Swift's4 researches seem to indicate that nearly every student ex-
amined had some visual defect. Investigations in the schools
of Sioux City, Iowa, show something like 50 per cent, of de-

^ee Cohn, op. cit.. Chapters VIII and IX, for many tables presenting the re-
sults of examinations in various countries.

1 Rules for the Care of the Eyes; published by Michigan State Normal School.
s Op. cit., p. 57.
*Loc. cit.

182 BULLETIN OP THE UNIVERSITY OF WI8CON8IN.

fectives in the highest grades. In Rochester, New York, 31 per
cent, of the children in the high schools have defects of vision
which could be detected without any expert examination. And
so it goes. Prentice,1 Cohn,2 and others have recently shown
beyond a doubt that no individual can afford to go through life
without ascertaining the condition of his eyes ; and yet 40 per
cent, of our students report that they have never had their eyes
examined. It would indeed be a remarkable circumstance if
there was not stealthy thievery of nervous energy taking place
constantly in a number of these cases.

Because one is not conscious of a defect is not conclusive evi-
dence that he does not possess it. I take my vision to be the
standard, the normal, unless somebody has shown me better. If
I am born with a myopic eye and can scarcely see my hand in
front of me, I have no way of telling that I am not as other peo-
ple are. The only safe course is to 'have my vision measured
up to a norm or standard ; and if it does not fulfill requirements
to call to my aid the skill of the oculist and of the optician.

For the most part the eye has been used throughout racial his-
tory in discerning relatively large objects and those at a distance.
It has been only within the most recent period that such visual
co-ordinations have been required as are necessitated in our day
in the reading of print. Authorities agree that a child of five
or six, for instance, has not developed the visual capacities to
read ordinary print with safety. 3 When a child of this age is
set to studying a primer, printed in the type that such books
usually are, or at least have been in the past, he not only suffers
great strain, but injury is apt to result to the visual organ. Now
it is probable that even in adult life the reading of fine print
requires co-ordinations of ocular muscles which result in dissi-

1 The Eye in Its Relation to Health.

*Op. cit.

8 See, for instance, Oppenheim, The Development of the Child, Chapter V; also
Dewey, The Fetisch of Primary Education, Forum, May, 1898. Indians are Baid
to have difficulty in accommodating their vision to print.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 183

pation of nervous force. Cohn,1 Sanford,2 and others have cal-
culated the size and shape of letters which can be read with
greatest ease. Burnham3 summarizes the results of investiga-
tions upon this subject in an excellent way and his words may
be quoted :

"1. Size of the Letters. It is necessary that type be easily legible at a
distance of twenty inches. For this it is necessary, according to Dr.
Cohn's estimate, , that the letters be 1.5 mm. high. 'Any type that is
smaller than 1.5 mm. is injurious to the eyes.' An angle of five minutes
is sufficient for the recognition of a letter; hence, according to the es-
timate of Dr. Weber, a healthy eye can read clearly a letter .7 mm. in
height without extreme convergence; but such reading is very laborious,
Weber tested the time occupied in reading with different types. When
the size of the letters was greater than 2 mm., he found that the speed
of reading was retarded. He decided for a minimum of 1.5 mm. Eulen-
berg and Bach demand still larger type for the lower classes. Many
of the school books in common use have much smaller letters than
Weber's minimum. In some of the school atlases, letters only .5 mm.
in height are used. Many very beautiful maps also have very small
type. Especially before pupils have become familiar with the letters,
it is necessary to have large type. Javal wishes to have it determined
by experiment how large the type should be in the different classes in
order that no pupil, however bad the light, need bring his eyes too near
the book.

"2. The Thickness of the Letters. 'No print of which the down stroke
is thinner than 0.25 mm. should be tolerated in school books.' In Latin
type the corners of the letters should be strengthened in order to make
them appear rectangular, otherwise by the irradiation of the white
ground they appear rounded off.

"3. The Shape of the Letters. Javal points out that, if the lower half
of a series of words be hidden from view, it still is easy to read them.
But when the uppe.- half is covered, it is difficult, often impossible, to do
so. In reading, we glance along the line at a little distance above the
center of the letters; and the letters g, j, p, q and y are the only ones
that come below the line. Thus the upper part of the letters are of
special importance. As the result of an extended research, Dr. Sanford
found several groups of letters in our alphabet that are relatively poor.
Of the small letters c, e, o are conf usable with one another; a, n and u
are poor letters; and s, i, 1, t are liable to cause confusion. Javal, Cat-

1Op. cit., Chap. XXIII.

2 The Relative Legibility of the Small Letters, Am. Jour, of Psychology, Vol. L
pp. 402-435.

8 Op. cit., pp. 49-51.

184 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

tell, and Sanford have each suggested changes for improving the form
of some of the worst letters. Among the most important of these are
Javal's suggestion that letters be made broader, and that we return to
the more open forms of c, e, and o, and Sanford's suggestion that a let-
ter in shape of an inverted v or of a small cap a might be substituted
for our present small a.

"4. The Approach. The distance between letters and words, or the
approach, is important. Every letter stands out with especial distinct-
ness when the space between two letters is wider than the space be-
tween the ground strokes of the letter. For this reason words are em-
phasized in German by spacing the type. This greater approach adds
to legibility. School-books should have an approach of nearly 1 mm.

"5. 'Leading' Is Important. 'A book has good interlineage,' according
to Dr. Cohn, 'when, if the letters are 1.5 mm. high, the lines are 3 mm.
apart.' A distance of 2.5 mm. (1-10 of an inch) is the smallest admis-
sible. Many of the old books had wider interlineage than is usual at
present.

"6. The Length of the Lines. The shorter the line the more easily
can one read. Javal thinks the long lines the cause of progressive
myopia in Germany. According to Dr. Cohn, the greatest length of lino
should be only 10 cm. Weber would have lines from 14 to 15 cm. in
length.

"Dr. Cohn resumes his rules as follows: 'In the future I would have
all school authorities, with measuring rule in hand, place upon the
Index librorum prohibitorum all school-books which do not conform to
the following measurements: The height of the smallest "n" must be at
least 1.5 mm. (.06 inches), the least width between the lines must be 2.5
mm. (.1 inches), the least thickness of the "n" must be .25 mm. (.01
inches), the shortest distance between the letters .75 mm. (.03 inches),
the greatest length of text-line 100 mm. (4 inches), and the number of
letters on a line must not exceed 60.' "

It is of course difficult for a student to alter the type of his
text or reference books, and attention is directed to the matter
here chiefly in the hope that those who have the choosing of such
books may take this energeic question into consideration. It is
of especial significance perhaps to students in the languages who
have occasion to consult dictionaries freely.

Attention has been directed thus far to the waste entailed by
needless tensions resulting from a worry ful mind, from the use
of implements requiring unnecessary co-ordinations, from de-

0 SHEA — A8PECT8 OF MENTAL ECONOMY. 185

fective vision, and from too concentrated employment of the
eyes. Before leaving this general topic, a word should be said
regarding another factor in the causation of wasteful tensions.
The human body in a standing or sitting position is, as every-
body knows, acted upon by gravity, and if it be thrown out
of plumb, so to speak, it tends to fall to the earth. This catas-
trophe can be averted only by the action of muscles which pull
against gravity, and so serve to keep the body in equilibrium.
Suppose now a person on foot or in his seat in such a posture for
some time that gravity has a leverage on him, and his muscles
are doing their best to prevent his falling ; it is easy to see what
this means in terms of nerve force. It involves nothing less con-
sequential than a ceaseless drain upon the system. People who
do not habitually stand or sit in such manner that the body is
poised, as it were, and at rest, will certainly suffer for their
error in lessened efficiency in both physical and mental work.

This principle is of special value to a student as it relates
to the position he habitually takes while engaged in study. In
order that this position may comply with the requirements of
economy in the expenditure of nervous energy, the study desk
and chair must be exactly adjusted to the bodily measurements
of the individual so that while using them there may be little oc-
casion for muscular strain. !No statistics have been gained re-
garding local conditions in respect of this matter, since in order
to be of value they would require considerable exact measure-
ment and this we could probably not have secured ; but it is not
unreasonable to suppose that students have not accidentally and
in all cases hit upon the proper regulations respecting the height
of desk and chair and their "distance" relations to each other.
Now, recent investigation has established something like a law
of hygienic seating Lincoln,1 Barnard,2 Marble,3 and others
in our own country and many scientists abroad4 have given much
attention to this subject during the past few years, alike in the
study of the physiological conditions which should govern seat-

iThe Sanitary Conditions and Necessities of School-houses and School Life.

'School Architecture, New York, 1860.

3 Sanitary Conditions for School-houses.

4 See The Pedagogical Seminary, June, 1892, for a summary of investigations.

186 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

ing and in the detailed measurements of many thousands of
individuals of different ages to ascertain in a general way the
requirements for persons of different ages. Meyer's statement1
of principles is as follows :

"The two seat-bones are curved like a bow; a line joining the lowest
points of these two bones is called the seat-bones line; the center of
gravity of the body is in front of the ninth or tenth chest vertebra; and
a straight line from this point to the ground is the line of gravity. Up-
right sitting is possible only when this line passes through the seat-
bones line. This line determines the surface of support for the body.
But the least movement that displaces the center of gravity makes up-
right sitting impossible without great muscular effort. The surface of
support is then determined by some third point. In a forward-sitting
posture the line of gravity falls in front of the seat-bones line, and the
third point that determines the surface of support is given by the edge
of the form, or when the seat is not broad, by the point where the feet
come in contact with the floor, or by both points together. The line of
gravity may now fall on that surface which is determined by the front
edge of the seat and by the muscular effort required to keep the body
in equilibrium. Hence the nearer to the knee the seat extends, the
larger the surface of support and the easier it is to retain the equilib-
rium. All the demands for an upright sitting posture would now be
satisfied if the trunk were immovably fixed in the hip-joint, but it is
joined movably to the thighs; hence the upright posture can be main-
tained only by the work of the pelvic muscles. The muscles soon be-
come fatigued and the body would fall forward unless supported by
leaning the chest and arms against the table.

In the backward-sitting posture, in which the line of gravity falls back
of the seat-bones line, the end of the coccyx is the third point which de-
termines the surface of support. This position has the great advantage
of having this third point fixed and immovable. The body with this
backward inclination should be supported by a back rest. This may be
placed against the shoulders, but then the position is a half-reclining
one. The lower down it is placed within certain limits the more it
helps in an unright posture. Placed at the upper edge of the hip-bone,
or back of the last vertebra, it holds the pelvis and the trunk in an up-
right posture. The principle then is as follows: A pupil must always
take those positions in sitting in which the line of gravity falls a little
back of the seat-bones line. The upper part of the body also must be
supported. It is easy to determine the kind of seat that should be used
in accordance with this principle."

1 Summarized by Burnbam, op. cit., p. 40.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 187

All that can be attempted here in this discussion of seating is
to direct the attention of the student to the importance of the
matter in the hope that he will try to arrange his chair and desk
so as to save nervous wear and tear to the fullest possible extent.
One suggestion may be made, however, that there should be a
back-rest to the chair, and it should support the back under the
shoulders and above the hip-bones. In Saxony there is a state-
regulation to the effect that school seats must be provided with
shoulder rests and cross back-seats. The distance of the chair
from the edge of the desk should be such that the student while
sitting ereot can place the fore-arms on his desk without stooping
or without elevating the shoulders.. In order to meet this re-
quirement the top of the desk should overlap the seat by two
or three inches — there must be a "minus" distance, in technical
phraseology. This is rarely found, in my experience, in stu-
dents' rooms, for the reason that it involves some bother getting
free from the desk; but the greater comfort thus ensured, and
the energy conserved would more than outweigh the slight trou-
ble which such an arrangement would occasion.

The matter of seating is of consequence not simply from the
point of view of saving energy, but it has an important influence
also upon the generation of force. A student leaning over his
desk, with his lungs constricted and the arteries leading to the
head compressed, is in a good way to foster mind wandering and
napping. The organism then becomes clogged, as it were; it
does not receive its due of oxygen, as a result of which the brain
must certainly become seriously handicapped.

§2. The Daily Program. — During the past decade a great
deal has been said, alike in the educational and in the secular
press, regarding over-pressure in education. Physicians and
educators have noted with great apprehension the apparently in-
creasing number of pupils in the higher schools who are defi-
cient in that vigor and robustness of body and mind which are
essential for success in the battle of life. We are told that
nervous diseaises are much, more frequent in youth today than
they were a generation ago, and the fault must lie with the

188 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

schools ; they pass the safety line in the demands they make upon
their pupils. This feeling has been so marked and wide-spread
that investigations have been prosecuted in Europe, and to some
extent in our own country, to ascertain the true condition of af-
fairs respecting the amount of work required of students. Thus
far little of definite scientific value has been attained ; but yet
the conviction is deepening in the public mind that education
is too much of a forcing process which calls upon energies that
should be utilized in the growth of vital organs. Physicians
have been urgent in their demands that the work of the schools
be lightened. Oppenheim1 is unsparing in his criticism of the
present regime as it exists in the lower grades. Keating,2 after
long experience with diseases of children, finds that many of
them have their origin in excessive strain incident to school
work, and he too insists upon reform. Examinations of the
school children of Germany have shown that in some instances
they return to their work day after day with constantly increas-
ing fatigue ;3 recuperation cannot take place fully during periods
of release from recitation and study. While, so far as I am
aware, no researches of just this character have been made upon
fatigue in university life, yet many persons of good judgment
are confirmed in the belief that even here students are over-
worked, and suffer in consequence thereof in some such way as
do overtaxed children in the lower schools.

Some effort has been made to determine the amount of study
which may be safely undertaken by a student at different stages
in his progress through the schools. It must be apparent, how-
ever, that it is impossible to formulate any general law respect-
ing this matter. Individuals differ so greatly in the amount
of energy which may be expended in intellectual and physical
activity that no rule could apply to all. Again, the kind of work
done and the conditions under which it is prosecuted must exer-
cise an important influence upon the readiness with which en-
ergy is expended. Some investigators are of the opinion, though,

lOp. cit., Chapter V.

^Mother and Child, pp. 180, 219. 2120.

'Kraeplin: A Measure of Mental Capacity, Pop. Sci. Mo., Vol. XLIX, p. 758.

o'SHEA — ASPECTS OF MENTAL ECONOMY. 189

even regarding these varying and modifying factors, that uni-
versity students on the whole cannot undertake with safety more
than eight hours a day of difficult intellectual labor.1 It is im-
portant to note, however, that during these eight hours the at-
tention is to be concentrated upon mental tasks ; mind wander-
ing and reverie are not to be considered as work. If we com-
pare the stint of our students with this as a sort of standard
we find that some work too much, while others do not tax their
energies to a legitimate extent. One student reports one hour
spent in study ; four, two hours ; twelve, three hours ; thirty-four,
four hours ; fifty, five hours ; seventy-two, six hours ; thirty-nine,
eight hours ; eleven, nine hours ; thirteen, ten hours ; four, eleven
hours ; one, fourteen hours. It is probable that the students re-
porting one or two hours devoted to study did not take into ac-
count time spent in the laboratories, so that their estimate is of
no value to us here. About all that can be said is that students
working ten, eleven, and fourteen hours a day are likely to draw
too heavily upon their resources.

And yet it should be remarked in passing that the injurious
effects of study upon the health of students is in all likelihood
due more largely to the unhygienic conditions under which the
work is carried on than to mental application itself. It seems
to be true that during waking life the mind is constantly active
in some direction ; and if study could be done under proper con-
ditions, it is probable that it would be no more fatiguing than
other sorts of mental occupation. It seems to me it is really
not so much a question of the amount of study as of the circum-
stances under which the study is carried on;2 except, of course,
that if one spends fourteen hours a day over his books he cannot
meet the requirements in respect of exercise and sleep discussed
above.

1See a summary of six articles on mental fatigue, Psychological Review, Vol.
IV, p. 548, et. seq. President Elliot recommends his students to spend but eight
hours in study. Kellogg, in Good Health for March, 1900, says the old rule
of eight hours for work, eight hours for exercise and meals, and eight hours for
sleep, is one that ought to be obeyed by every persoD.

sSee O'Shea: The Hygiene of School-work; Kindergarten Review, May, 1899.

190 BULLETIN 0? THE UNIVERSITY OP WISCONSIN.

Looking now at some of the regulations in accordance with
which one's study should be prosecuted, it may be seen that one
of the most important requisites for economy is the concentra-
tion of attention upon any given topic for unbroken periods, dif-
fering in length with individuals, with age, and with the nature
of the subject attended to. Common-sense tells us that one may
accomplish more with less effort when he holds his mind to a
task than, when it is constantly wandering into by-paths ; and
neurology has produced some evidence giving warrant to this
view. It has pointed out that there is what one might call divi-
sion of labor in the cerebral factory. In one section is carried
forward a certain variety of work, in another a different kind ;
and so each department has its special duties. r jSTow if one be
attending to mathematics, for instance, it is probable that a
special department of the brain is particularly active. The
memories and the associative functions in that region are aroused
and energetic. And the longer one holds his attention to this
subject, up to a certain point, the clearer are obscure relations
discerned and the more rapidly does thought proceed. In a neu-
rological sense this means that the inertia of the brain in a
special area is overcome and energy moves along desired lines
with less resistance than at the outset. But now let the atten-
tion wander unbidden into another field ; it must arouse inactive
regions of the brain that for the time being ought to remain dor-
mant. This dissipates both time and vital force.

It must be familiar to every one that solving a problem and
learning a poem at the same time is bad economy. So, too, it is
a wasteful practice to try to master one's psychology or literature
or mathematics while listening to the conversation of a room
mate, or while one's mind is idly straying off into neighboring
regions of either study or anticipated pleasures. The conserva-
tion of mental energy requires that a student should have cer-
tain periods when he is wholly uninterrupted and can give his

1See Donaldson, op. cit., Chapter on Localization of Function for an exposition
of the theory. The literature of the subject is very extensive and any one in-
terested might consult Flechsig, op. cit.; Ferrier, Localization of Function. Munk,
Horsley, Schafer, Hitzig, Meynert, Brocca, et al., have written much on the
subject.

O'SHEA — ASPECTS OF MENTAL ECONOMY. 191

attention absolutely to the task in hand. He should put out of
sight and hearing every stimulus which tends to distract atten-
tion. One cannot urge too strongly the desirability of fraterni-
ties and rooming houses having a rigid law that during certain
study periods there shall be a gag on every mouth and a mill-
stone attached to every heel.

A large number of our students — over forty per cent. — re-
ported that their study periods are interrupted ; some have only a
very brief period during which they are certain of being unmo-
lested. Five reported one hour that could be given without in-
terruption to study; twenty-two, two hours; forty-seven, three
hours ; fifty-four hours ; thirty, five hours ; twenty-eight, six
hours ; thirteen, seven hours ; five, eight hours ; one, nine hours.
Engineers have little time that is given uninterruptedly to study
aside from their laboratory work. This report indicates a need
of reform, for more reasons than one, too. It has already been
said that interruption involves waste; but it has an even more
serious psychological effect. In order to discover the deeper re-
lationships existing between ideas in any field one must have
long periods for reflection. It is to be feared that many of our
students do not have leisure to explore the depths of the subject
which they study; they simply attach ideas to the mind in a
sort of tangential fashion through the exercise of the verbal
memory. Reason seems to prosper only in relatively long per-
iods of application, while the mechanical memory may utilize
profitably mere snatches of time.

While economy demands uninterrupted periods for study, yet
this does not mean that the student should apply himself five or
six or seven hours without any relaxation. On the contrary
investigations by Burgerstein,1 Holmes,2 Kraeplin,3 and others
show that greater progress is made in the intellectual operations
if attention be not constrained to a given task beyond the point
of fatigue.4 If at the approach of fatigue the attention be re-
leased for a time it will return with renewed vigor and in the

lPed. Sem., June, 1892, pp. 60, et. seq.

sPed. Sem., Vol. Ill, pp. 213-234.

^Loc. cit.

«Cf. Newsholme op. cit., p. 66. Also Kotelmann, School Hygiene, Chap. XIII.

192 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

long run accomplish more than if it be held continuously regard-
less of cerebral wear and tear. Efforts have been made to as-
certain the span during which attention can be profitably held
to a subject; but as in the case of the amount of work which can
be done, the result must be purely relative ; it depends upon the
subject and upon the individual. It is thought by some, though,
that in general fatigue intervenes after twenty minutes concen-
trated effort in the early years and sixty minutes or thereabouts
in maturer life.1 It is probable, however, that a vigorous adult
possessing a well organized brain can apply himself to one sub-
ject for a longer period than an hour. Experience and the prin-
ciples of neurology both warrant the hypothesis that energy gen-
erated in one part of such a brain may be utilized readily in
carrying forward work in other regions.2 But the association
fibers which make possible the easy transmission of energy from
one cell to another do not apparently attain their complete de-
velopment until about the age of thirty-three, as is indicated in
Eig. 17.

Now if the assumption be true that the associative fibers serve
as energy-carriers between the various cerebral departments, and
these fibers are maturing constantly until middle life, then it
follows that the Senior in the University should, other things
being equal, be able to apply himself with profit for longer
periods than the Freshman. But it is certainly impossible in
the present state of our knowledge to say just how long should
be the study periods of either the Senior or the Freshman. All
we are warranted in saying, which is far from as definite as can
be desired, is that attention should be concentrated upon a single
subject at a time and held to it until the approach of fatigue,
when it should be released. If the same study is to be contin-
ued, a break of ten minutes passed in moderate physical activi-
ties will aid in the removal of worn out materials from the brain
and in securing a fresh supply of blood in the cerebrum. It is

2See Ped. Sem., June, 1892, pp. 64 and 65.

2Flechsig: Oehirn und Seele, presents strong evidence in favor of the view
that energy generated in one part of the brain may be put to use in remote reg-
ions. See also Curtis: Inhibition; Ped. Sem., Vol. VI, No. 1, for a valuable dis-
cussion of the subject.

O'SHEA — ASPECTS OF MENTAL ECONOMY.

193

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12

194 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

important, though, that the relaxing exercises should not de-
mand just as great concentration of attention as the study ; the
purpose in relaxing, which was argued in the preceding chapter,
is to relieve the will, to set it free, when it will return with re-
newed vigor to mental tasks.

The sequence of studies in the day's work is an important sub-
ject for the student. The principle governing this matter is de-
pendent upon the neurological fact already discussed, that dif-
ferent regions of the brain have charge of characteristic mental
activities. When then the mathematical center has been exer-
cised for a reasonable period, economy would suggest that this
be relieved while other areas be employed. To follow one
mathematical study by another is not the part of wisdom unless
the first has used but a fraction of the available energy. If it
were possible it would be advisable to keep the attention con-
centrated upon a subject, as mathematics or literature, until the
energy which can be utilized in that direction is largely spent;
then turn to another study of a different character. This is not
so important for the mature as for the immature brain-worker ;
a Senior should be able to disregard the law of sequence in stud-
ies with greater impunity than a Freshman. He can draw more
largely upon all his resources for special purposes ; he can sum-
mon most of his strength, totalize it, as it were, on occasion.
But yet even with the upper classman prudence would advise ar-
ranging the day's program so that studies employing different
mental activities should relieve one another. This is especially
important in relation to the mental and motor branches. If a
student has to prepare three subjects during the day, two of
which require much writing and the third none at all, it would
doubtless be best for him to put the non-writing subject between
the others, so that the cerebral motor regions employed in writ-
ing may perform the required tasks without exhaustion.

A student does not have entire option respecting the hours
of the day which can be spent in study, but yet the matter is
under his own control in some measure. A few of our students
have contracted the habit of visiting in the forenoon and study-

O'SHEA — ASrECTS OF MENTAL ECONOMY.

195

ing at midnight, going on the principle that one hour is as good
as another for study and the fresh morning hours are the best
for social pastimes. But practically all those who reported
testified that their minds worked best in the forenoon ; eighteen
reported being best in the afternoon, while two found they could
accomplish more at 5 o'clock in the morning than at any other
hour. The best hours ranged from 7 to 12 in the forenoon,
while the choicest period of the day is from 9 to 11. These
hours accord with investigations made by Lombard, although
his results are not by any means conclusive, since too few sub-
jects have been studied and disturbing factors such as the influ-
ence of alcohol, tobacco, and food, make his data in a measure
unreliable. Still his curve showing the rhythm of daily fatigue
is at least suggestive, and may be given here:

8 & iQiiit i a j -^ s fe t e 9 to n ia i a s <+ s c.

en — i — i — i — i — i — i — i ■■ T i — i — r ' r • — r— — i — i i T-i t^-t

ZcO*.

£00

IfcC

120

■♦Ci

Fig. 18. — Showing at each hour of the day and night how many centimeters
a weight of 3,000 grammes could be raised by repeated voluntary contrac-
tions of the forefinger before fatigue set in. The curve is highest at 10 to
11 a. M. and 10 to 11 p. m. Lowest 3 to 4 p. m. and 3 to 4 a. m. Circle with
dot observation made just after taking food ; square with dot smoking ;•
work done eight minutes after drinking fifteen cubic centimeters of whisky.
(Donaldson after Lombard.)

There can be little doubt that for most people the morning
hours are the most profitable to be devoted to diligent, concen-

196 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

trated study. The afternoon hours can be employed to greater
advantage in duties demanding less energizing of the will;
while in an ideal program the evening hours will be spent al-
most wholly in relaxation. Considering the number of hours
our students devote to study they would, it seems, have ample
opportunity to accomplish all of their tasks during the day if
they would economize in the ways that have been suggested.
The arrangement of a program on this basis is very desirable
from many points of view, social and otherwise ; but one point
especially needs to be made here. It is probable that much
study late at night results in a disturbance of sleep. Ninety-
three students reported that their sleep was greatly disturbed
by dreams ; and while people who do not study at night dream,
still it is certain that intense mental application throws the
brains of most people into an excited condition which is inim-
ical to refreshing sleep. People who dream much waste nerv-
ous energy; the mind is active but without profitable outcome.
For those who dream after night study it would surely be bet-
ter economy to work intensely during the day and devote the
evening to relaxation and social pleasures which will woo Mor-
pheus to their bedsides when the day is over.

The majority of our students do not usually study later into
the night than is ordinarily thought to be healthful. Two re-
ported not studying beyond 8 o'clock; forty-four worked until
9 o'clock, one hundred and eighty-seven until 10 o'clock, sev-
enty until 11 o'clock, nine until 12 o'clock, and one until 1
o'clock. One hundred and four students have studied all night
on occasion. Eighteen of these said that it did them no harm,
while eighty-six felt "bad, sleepy, dull, tired, ragged," and had
no ambition to work the following dav. Fortv of those who
studied very late into the night testify that the knowledge they
acquired remained with them ; fifty-eight said that in the morn-
ing it, like the Arab, had folded its tent and silently slipped
away.

§3. Tell me what company you keep and I will tell you what
you are. — Most of us have little appreciated the importance

O'SHEA — A8PECT8 OF MENTAL ECONOMY. 197

of this old adage, although we see its truthfulness il-
lustrated every day of our lives. We realize that we gradually
become like those with whom we associate. I cannot be in
the presence of a friend without unconsciously but yet surely
incorporating into my own activities his peculiarities of voice,
facial expression, carriage, gesture, and so on. The subcon-
scious phase of personality seems to be charged with the re-
sponsibility of making the individual like his environment.
When he looks upon a face showing constraint of lips and eyes,
he tends to reproduce these tensions in his own features; if
he listens to a high-pitched, raspy voice, he feels a strain in
his own vocal organs. And so it goes, throughout the whole
gamut of human activities ; people that go together get to act and
even look alike I1

Physiologists in our day are calling attention to the vast im-
portance in human life of this method of suggestion or imita-
tion, whereby we take as copies the people around us and mold
ourselves upon them;2 and it is of especial importance as it
relates to the economv of vital forces. When we are in the com-
pany of people who are fatigued, who are over-scrupulous,
fussy, tense, and constrained in all their expressions, we quickly
reproduce their tensions and so waste energy. Most of us in-
stinctively avoid these "bottled lightning" people, these nerv-
ous hypochondriacs ; the preservation of life demands it. Now,
a student cannot always determine the company he keeps, but
yet he is in a way master of the situation ; and if he be of the
type easily suggested to he should above all things avoid living
in the same quarters with a neurotic individual, for if he does
his forces will steadily run off without profitable issue. To
choose a well-poised and well-nerved room-mate is one of the
most important undertakings which can engage the attention
of a student. If it should be asked, what will become of the

1See for a great many illustrations of this law, Russell: Imitation and Al-
lied Activities; Small : The Suggestibility of Children, Ped. Sem., Vol. IV, No. 2;
Sidis : The Psychology of Suggestion, Parts on Normal Suggestion and Social
Suggestion.

2 See Baldwin, Mental Development, Methods and Processes, Chapters VI and
IX, X, XI, XII ; Vernon Lee and C. A. Thompson : Beauty and Ugliness, Con-
temporary Review, Vol. 72, pp. 544-569, and 669-688 ; Scripture : The New Psy-
■cholog-y, pp. 248-261 ; Wundt : Human and Animal Psychology, pp. 323-339.

198 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

neurotics, it must be answered that the law of the survival of
the fittest should have its way in student bodies as elsewhere.
At any rate it is a sacred duty to conserve against injury from
any source the best, whether moral or physical, that has been
given to us in human life.

gtot of SittUetina 3**sttcs itt the Science Zkevie*

Volume 1 :

No. 1. On the Speed of Liberation of Iodine in Solutions of Hydro-
chloric Acid, Potassium Chlorate, and Potassium Iodide, by Herman
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No. 3. Studies in Spherical and Practical Astronomy by George C.
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Herbert Hobbs, Assistant Professor of Mineralogy and Petrology. Pp. 48,
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No. 5. Analytic Keyes to the Genera and Species of North American
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Volume 2 :

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of Taste, by Louis Kahlenberg, Ph. D., Assistant Professor of Physical
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No. 2. Aspects of Mental Economy. An essay on some phases of the
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In preparation:

Contributions from the Anatomical Laboratory of the University of
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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 33

Science Series, Vol. 2, No. 3, Pp. 199-246, Pus. 3-is

CONTRIBUTIONS FROM THE ANATOMICAL LABORA-
TORY OF THE UNIVERSITY OF WISCONSIN

EDITED BY

WILLIAM S. MILLER

Assistant Professor of Vertebrate Anatomy

Published bi-monthly by authority of law with the approval of the Regents

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MADISON, WISCONSIN
February, 1900

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 33

Science Series, Vol. 2, No. 3, Pp. 199-245. Pls. 3-is

CONTRIBUTIONS FROM THE ANATOMICAL LABORA-
TORY OF THE UNIVERSITY OF WISCONSIN

BY

WILLIAM S. MILLER

Assistant Professor of Vertebrate Anatomy

LIBRARY
NEW YORK
BOTANICAL

UARUfclN.

Published bi-monthly by authority of law with the approval of the Regents

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
February, 1900

CONTENTS.

PAGE

Introduction ....... 201

The Lung of Necturus maculatus (with plates 3-8) . . 203

The Vascular System op Necturus maculatus (with plates 9-11) 216

The Brain of Necturus maculatus (with plates 12-13) . 235

The Epithelium of the Peritoneal Cavity of the Cat (with

plates 14-15) ....... 245

INTRODUCTION.

The University of Wisconsin requires that each student shall,
before graduation, write a thesis on some subject selected either
by himself or the professor under whom the work is to be done.

The subjects of the following four papers were suggested to
the students, named below, of the class of 1898. The results
of their work were so satisfactory that I have quite largely in-
corporated them in the present Bulletin.

The description of the vascular system of Necturus macu-
latus I hope will be of assistance to those who use the animals
in their laboratories. For several years I have used them in my
course in vertebrate anatomy, and feeling the need of some
detailed description of the blood-vessels, I kept notes on each
animal used. The results, as embodied in the present paper,
represent the dissection of over 200 animals and cover four
years' work.

Those who have used Necturus in laboratory courses know
how variable they are. The text and diagrams represent the
most constant type. I regret that I have not been able to con-
sult what is practically the only work on Necturus that is known
to me, "Ontleed en dierkundige bydragen tot de Kennis van
Menobranchus, den Proteus der Meeren van Noord-Amerika."
J. van der Hoeven. Leiden, 1867.

I should be very glad to receive any corrections which other
workers find desirable on comparison with their own notes ; also
suggestions on the nomenclature, which I realize is faulty in
some places.

202 BULLETIN OF THE UNIVERSITY OF "WISCONSIN.

The following gentlemen of the class of '98 have assisted in
the preparation of these papers :

H. W. Ochsner : The Lung of Necturus maculatus.

A. Sauthoff, J. H. Van Vorhis : The Vascular System of
Necturus maculatus.

C. A. Squire : The Brain of Necturus maculatus.

A. W. Meyer. The Epithelium of the Peritoneal Cavity of
the Cat.

These papers by no means represent all the worthy work done
in the Laboratory. Some of the subjects are being worked out
gradually; a few points this year, a few more the next and so
on until at last they can be gathered up into a complete paper.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 203

THE LUNG OF Neciurus macuUtus.

The lungs of Neclurus consist of two long, narrow, transpar-
ent membranous sacs, which extend backwards into the abdomi-
nal cavity dorsal to the other viscera. Their outer surface is
perfectly smooth and is covered by a layer of the peritoneum
lining the pleuro-peritoneal cavity, thus forming a mesentery
which attaches them to the dorsal body wall along almost their
entire length. In a full-grown specimen, whose lung is from
100-125 mm long when distended, less than 25 mm is free.
Each lung is a perfectly simple sac, no septa being developed,
and their cavities open into the pharynx through a common mem-
branous tube running in the dorsal wall of the pericardial cav-
ity. This tube represents the trachea of higher vertebrates.

The epithelium, which forms the outermost layer (serous
layer) of the lung of Necturus, varies in size and outline in the
various parts of the lung, as may be seen from PI. 3, figs. 1, 2 ;
PI. 4, fig. 3. Between the large blood-vessels and especially in
the anterior part of the lung, the epithelium is of the common
type, as shown in PI. 3, fig. 1. It consists of large, thin, ir-
regular cells with comparatively smooth boundaries. The nuclei
of these cells do not seem to occupy any one characteristic posi-
tion, but are found in all parts of the cell. Toward the pos-
terior end and along the sides of the blood-vessels we find the
cells taking on a longer and a narrower shape, making them ir-
regularly oblong, as shown in PI. 3, fig. 2. The nearer we ap-
proach the tips of the lungs, the narrower and longer do the cells
become. Between the lateral branches of the blood-vessels we
very often find whorls of cells, centering around a rather large
irregular one. Covering the blood-vessels and lymphatics we

204 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

have an entirely different type of epithelial cell, as shown in
PL 4, rig. 3. The cells are often extremely long and always
have very jagged edges, more so than the figure indicates. Be-
tween these types we find all gradations, though the last type
passes over into the others very abruptly, as a rule.

In all my specimens I was not able to see a single spot or ori-
fice which I could construe to be a stomata. It is true that
there were some small spots in some of the preparations, but they
could always be traced to over distention, tearing, or drying of
the lung. Indeed, they could be produced in any quantity by
just such procedures.

Along the inner side of the lung, near the pulmonary vein,
pigment cells are often found which present many bizarre
shapes.

THE PULMONARY EPITHELIUM.

If a Nedurus be killed by cutting off its head and one of its.
lungs be removed, cut open and spread out on a slide in salt solu-
tion, and its inner surface examined under a medium power, it
will be seen that the epithelium is apparently collected into
groups or islands of cells which are surrounded by clear spaces.
This arrangement coincides with that given by Schulze, Schmidt
and Ranvier for the frog, and by Williams and Stirling for the
newt.

Schulze describes the relation between the capillaries and the
epithelium of the lung of Reptiles and Amphibians as follows :

"All respiratory capillaries are attached to the alveolar wall only
on one side. They would project freely, with their greatest circum-
ference, into the air cavity, if they were not completely covered by
a continuous plate-like epithelium. The large polygonal cells of this
alveolar epithelium, meeting accurately at their sides, cover the sur-
face of the capillaries, turned toward the air cavity, with thin, trans-
parent, plate-like expansions and send plug-like continuations, gen-
erally the nucleus with some surrounding protoplasm, into the cap-
illary network and indeed so far down that they reach the connective
tissue stroma of the alveolar wall, and so completely fill the spaces
of the capillary network. These plug-like continuations, harboring

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 205

the nucleus and protoplasm of every cell, are usually found in the
corners of the single cells, so that several plugs lie together and are
found in a single capillary mesh. Still, many cells are also found
which bear their granular continuations nearer the middle and com-
pletely fill a capillary mesh."

Williams savs :

"The epithelial scales which cover the capillary areas of the lung
of the newt (parts which coincide with air-cells of the mammalian
lung) lose not only the external appendages (cilia), but also their
internal parts (nuclei and granules). This successive reduction leaves
nothing but a hyaline involucrum enclosing a pellucid fluid."

Stirling also investigated the lnng of the newt and says :
"The arrangement of these cells is curious. They lie in groups,
and the large nuclei occupy the small spaces left between the blood-
capillary network, whilst the thin plates of each cell cover the cap-
illary wall. The result of this arrangement is that the air in the
lung is separated from the blood-stream merely by the cell plate of
these cells and the squames which form the capillary wall."

If now the remaining lnng be carefully removed and stained
by means of nitrate of silver, the outline of the cells and their
nuclei will be brought into view. PL 4, fig. 4, shows the out-
line of the cells, also that of the islands in which the nuclei and
protoplasmic part of the cells are situated. PL 5, fig. 5, shows
the relation of the nuclei and protoplasm to the cell boundaries
in a case where several nuclei are found in a single mesh of the
capillary network. Sometimes we find a single nucleus filling
the whole mesh and lying near the center of the cell, as shown
in PL 5, fig. 6. Sometimes we find the cell boundaries appar-
ently cutting through a nucleus, as we see them doing in a few
instances in PL 5, fig. 7. This is merely a condition due to the
over-lapping of one cell by another, as was shown by Schmidt
in the case of the frog. A projection of the relation of the
nucleus to the boundary lines is shown in PL 5, fig. 8.

To demonstrate the presence of cilia the .animals were killed
by pithing ; the lung was then removed and cut open along both
the artery and the vein. The cilia were seen to better advantage
at the edges of the preparation than on the surface. Ciliated

206 BULLETIN OP THE UNIVERSITY OP WI8CON8IN.

epithelial cells were found over both the artery and vein, down
to the apex of the lung, while a few were also found between
them. This is not the case in the newt according to Stirling ,
the ciliated epithelium being found only over the pulmonary
vein and its principal branches, while a plexus of capillaries lies
over the artery. Williams, in contradistinction to Stirling, fig-
ures the ciliated epithelium over both the artery and vein of the
newt. In Necturus I found a plexus of capillaries, as well as
the ciliated epithelium over both artery and vein.

THE ELASTIC FIBERS.

The elastic fibers of the lung of Necturus form an exceedingly
complex network, as shown in PI. 6, fig. 9. The fibers are of
two types, the coarser ones being nearer the surface, and form-
ing wider meshes than the finer and deeper ones. They also run
more generally in a direction parallel to the long axis of the
lung. The meshes of the fine fibers are exceedingly intricate,
especially around the blood-vessels. Stirling describes the elas-
tic fibers as forming a layer lying between the endothelium and
the layer of smooth muscle, but this cannot be said of the lung
of Necturus. Fibers are found scattered throughout the
walls of the lungs. PL 7, figs. 11, 12, show longitudinal and
cross sections of the lung of Necturus taken near blood-vessels
which show the fibers as dots or lines, according as they are cut
transversely or more or less longitudinally.

THE MUSCLE FIBERS.

The muscle fibers are of the involuntary type and run prin-
cipally in a circular direction, thus forming a tubular founda-
tion for the lung. The nuclei of the fibers are shown in PL 7,
figs. 11, 12 ; PL 8, figs. 13, 14. At the tip of the lung the fibers
form an intricate network, running in all directions.

Stirling mentions a difference in position of the vein and
artery with reference to the layer of muscle fibers, the artery
lying internal to this layer, while the vein lies externally to it.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 207

This does not hold true for the lung of Necturus, since both the
artery and the vein lie superficially, the greater part of the
muscle fibers lying internal to them. PL 8, figs. 11, 12, shows
the relation between the blood-vessels and the muscular fibers.
It will be noted that the relation is the same in both the artery
and vein.

THE NERVE FIBERS.

The distribution of the nerves in the lung is shown in PL 6,
fig. 10, and PL 8, fig. 15. Contrary to the usual opinion, we do
not find the main branches along the blood-vessels, but rather
between them. To be sure, there are nerve trunks lying over
the blood-vessels, yet they are not so large as those forming the
elongated meshwork between them. The anastomoses between
the trunks are quite numerous, increasing as they diminish in
size until we come down to the ultimate fibers.

This distribution is contrary to that found by Stirling in the
lung of the newt. He savs :

"The nerves enter the lung in three or four main strands at its base.
These strands are of unequal thickness, i. e., a varying number of
nerve-fibers enter into their composition. At once they proceed
towards the pulmonary vein, which they follow very closely in their
distribution. They form a plexus along the course of the vein. Only
a few non-medullated nerve-fibers pass on to the pulmonary artery.
The nerve-strands lie outside the muscular coat, and as they pass
onwards in the pulmonary walls they give off branches right and
left. A large number of multipolar nerve-cells exist in the course
of the nerve-strands, and they are especially numerous where a branch
is given off."

Both medullated and non-medullated fibers are found in the
main trunks. From this main network we get a second network
with fewer fibers in a branch, but still containing both kinds of
fibers. From this secondary network we have a fine network of
non-medullated fibers given off which breaks up into the ulti-
mate fibrils. These last I did not try to follow out to their
endings. Along the course of the fibers, as well as the trunks,
nerve-cells are present, and my observations in Necturus coin-

208 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

cide, except in the connections between the fibers and cells which
I did not investigate, with those of Stirling in the newt. He
savs :

"A large number of nerve cells are found along the whole course of
these mixed nerve strands and occur singly or in groups, and are
usually most numerous where branches are given off.

"They are not confined to the main trunks, however, but recur singly
or in small groups in the larger nerve branches. Sometimes the cells
lie singly between the sheath of the nerve and the nerve fibers, whilst
others lie crushed up as it were between the nerve fibers. As already
remarked, they are most numerous where a nerve twig is given off
from the main mixed strand. In these small aggregations of nerve
cells it is easy to trace the course of a medullated fiber sweeping clear
through the mass, and forming no connections with the cells, whilst,
occasionally, one may see a connection between a nerve cell process
and one of the non-medullated fibers. The shape of the nerve cells
seems to vary considerably; some appear to be bipolar, whilst others
are polygonal and have several processes, one or more of which may
become continuous with a non-medullated fiber. Each cell contains a
relatively large nucleus usually placed eccentrically, and the body of
the cell may or may not be enclosed in a capsule. Other nucleated
masses of protoplasm devoid of processes lie amongst the nerve fibers,
and it is not clear what is their exact nature. Perhaps they may
represent developing nerve cells."

TECHNIQUE.

The specimens were killed by chloroform, although some were
used that had been dead for a few hours, and those used for the
wrork on the epithelium were killed by pithing. The lungs were
removed by opening the body cavity at the left side of the
median ventral line and then cutting through the ventral mesen-
tery, which allowed me to throw back the flap of the body-wall,
thus exposing the whole of the viscera to view. The lungs were
carefully blown up with a syringe introduced through the mouth,
into the glottis. This made the lungs very prominent and it
was a comparatively simple matter to cut through the fold of
peritoneum, which attaches the lung to the body-wall. Care
was exercised, in handling the lungs, not to puncture them, as-

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 209

their walls were very thin. Threads were passed around each of
the lungs near their union at the anterior end of the liver and
then they were cut off and at once put into the fixing fluid or into
the stain as the procedure necessitated. As the lung was kept
distended by this method it allowed me to handle it without
touching the surfaces and at the same time produced a uni-
formly distended and perfectly smooth surface. On account of
the great amount of blood present in the lungs, it was found
necessary to remove it in some manner so as to be able to see
the finer structures, especially with a high power. This was
done by washing out the blood with normal salt solution, inject-
ing it into the main artery.

For the study of the peritoneal covering and of the epithe-
lium of the lung, the usual methods with nitrate of silver were
used. An interesting point was brought out while investigating
the epithelium, viz., that while on all ordinary serous membranes
Dekhuysen's method had given the most satisfactory results, in
Necturus it proved to be exceedingly unsatisfactory. This was
probably due to some action of the nitric acid on the peculiar vis-
cid secretion which covered the lungs ; for, when after many fail-
ures the simple aqueous solution was used, each cell appeared
bounded by clear and sharply defined lines.

For elastic fibers Hoehl's modification of TTnna's orcein stain
for the skin was used ; it gave uniform and very satisfactory re-
sults. For the nerves methylene blue was use with varying suc-
cess.

210 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

BIBLIOGRAPHY.

Hoehl, E. Zur Histologie des adenoiden Gewebes. Archiv f.

Anat. u. Phys., 1897. Phys. abth.
Miller, W. S. The Structure of the Lungs. Jour. Morph.

Vol. 8. 1893.
Stirling, W. On the Nerves of the Lungs of the Newt. Jour.

of Anat. and Phys., Vol. 16. 1882.
Schulze, F. E. Die Lungen. Strieker's Lehre von den Gewe-

ben. Leipzig, 1871.
Schmidt, C. De l'epithelium pulmonaire. Strassbourg, 1866.
Williams, Thomas. Art. "Respiration." Cyclopedia of Anat.

and Phys. Vol. V. Suppl. London. 1859.
Ranvier, L. Traite technique d' histologie. 1875.

Plate 3.

Description. of Plate 3.
Lung of Necturus maculatus.

Pig. 1. Epithelium between the large blood-vessels, x 165.

Pig. 2. Epithelium near the large blood-vessels and end of lung,
x 165.

BULL. UNIV. WIS.. SCI. SER.

VOL. 2, PL. 3.

Plate 4.

Description of Plate 4.

Lung of Necturus maculatus.

Fig. 3. Epithelium over the blood-vessels and lymphatics,
x 165.

Tig. 4. Epithelium within the lung showing outline of cells and
islands, x 250.

BULL. UNIV. WIS., SCI. SER.

VOL. 2. PL. 4.

Plate 5.

Description of Plate 5.
Lung of Necturus maculatus.

Fig. 5. Relation of nuclei and protoplasm to group of cells in an
island, x 350.

Fig. 6. A single cell forming an island, x 250.

Fig. 7. Cell boundaries crossing over nuclei of neighboring cells,
x 250.

Fig. 8. Projection drawing of two cells from figure 7, showing
relation of cell boundaries to nucleus and to two un-
derlying capillaries, x 250.

BULL. UNIV. WIS., SCI. SER.

VOL. 2, PL. 5.

Plate 6,

Description of Plate 6.

Lung of Necturus mi l,us.

Fig. 9. Surface view of elastic fibers over the pulmonary artery.
Orcein staining, x 400.

Fig. 10. The finer network of nerve fibers, showing meclullated
and non-medullated fibers and nerve cells. Methy-
lene blue, x 75.

BULL. UNIV. WIS.. SCI. SER.

VOL. 2, PL. 6.

Plate 7.

Description of Plate 7.

Lung of Necturus maculatus.

Fig. 11. Elastic fibers and muscle nuclei in a longitudinal sec-
tion of lung. Orcein staining, x 400.

Fig. 12. A transection of lung. Same preparation as figure 11.
x400.

BULL. UNIV. WlS., SCI. SER.

VOL. 2, PL. 7.

;-- Muscle nuclei.

— \Elaihc Fibres.

fig. n

Lumen
of

Bloodrv -esse/ .

fig. is.

Plate 8,

Descelption of Plate 8.

Leng of Necturus maculatus.

Figs. 13 and 14. These section? show, the relative thickness of
the layer of muscle fibers, both internal and external
to the artery and vein. ISTote the superficial situa-
tion of both vessels, x 40.

Fig. 15. The distribution of the main nerve trunks, x 3.

BULL. UNIV. WIS., SCI. SER.

VOL. 2, PL. 8.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 211

THE VASCULAR SYSTEM OF Necturus nutcuUius.

THE ARTERIES.

For convenience of description the ventral aorta and its
branches will he considered with the arteries although it con-
tains venous blood.

From both sides of the anterior extremity of the Truncus
Arteriosus, Tr. PL 9, and fig. 1, PI. 10, arise two vessels, a
smaller anterior and a larger posterior. For a distance of about
5 mm they appear as a single vessel, being separated merely by
a septum. The anterior, The First Afferent Branchial
Artery, A. B.-l, PL 9, and fig. 1, PL 10, runs out almost at
right angles to the truncus, to the first branchial cartilage, along
the postero- ventral edge of which it continues to the gill. In
the gill it runs along its ventral edge, giving rise to numerous
fine branches which subdivide and form a loop, with a capillary
network between, in each tuft. The posterior larger vessel also
runs out nearly at a right angle to the truncus parallel to the
first afferent vessel, then makes a sharp turn caudal, continuing
between the two posterior branchial cartilages. About 5 mm
posterior to the turn it divides into two branches, the Second
and Third Afferent Branchial Arteries, A. B.— II., A. B.
-III., PL 9, and fig. 1, PL 10. Each runs along the correspond-
ing branchial cartilage into the gill, where it breaks up in a man-
ner similar to the first.

The Efferent Branchial Arteries arise by numerous radi-
cles formed by the capillaries of the gill tufts uniting along the
dorsal edge of the gill to form a common vessel. Just at the
point where the First and Second Efferent Branchial Ar-

212 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

teries, E. B.-L, E. B.-IL. PL 9, and fig. 1, PL 10, leave
the gill, each gives off a branch which crosses the proximal edge
of the gill. The branch arising from the first efferent artery
forms the External Carotid, E. C, PL 9, and fig. 1, PL 10,
while the branch arising from the second efferent artery goes to
the second afferent branchial artery, E. B. a., PL 9, and fig. 1,
PL 10. The Second and Third Efferent Branchial Ak-
teries unite at the posterior edge of the second branchial carti-
lage. The vessel thus formed, C. V., PL 9, and fig. 1, PL 10,.
and the first efferent branchial artery are united by a short ves-
sel, A. B., PL 9, and fig. 1, PL 10, as soon as they enter the
buccal cavity, along the dorsal side of which they run. The
first efferent branchial artery, after giving off the above connect-
ing branch, A. B., makes a bend and runs directly cephalad as
the Internal Carotid, I. C, PL 9, and fig. 1, PL 10. The
vessel formed by the union of the second and third efferent ar-
teries, after giving off the pulmonary artery, P., PL 9, and fig. 1,
PL 10, is continued as one of the Aortic Roots, R. A., PL 9,
and fig. 1, PL 10.

The Internal Carotid, I. C, PL 9, arises from the first ef-
ferent branchial artery at the point where the anastomosing
branch is given off to the conjoined second and third efferent ar-
teries. It runs along the medio-ventral edge of the masseter
muscle and the ventral surface of the parasphenoid bone making
two convex and one concave turn towards the outside. It pierces
the parasphenoid opposite the first branchial cartilage, continues
along its dorsal surface for a short distance, about 8 mm, pierces
it a second time, and, running along its ventral surface, ends in
the premaxilla.

At a point just anterior to the first gill the internal carotid
gives off several branches. They pierce the parasphenoid bone
and emerge anterior to the pterygoid. The most posterior of
these branches, the Internal Inferior Maxillary, I. I. M.,
PL 9, runs under the tympanicum to the ramus of the lower
jaw, where it gives off a branch to the digastric and mylohyoid
muscles, a branch to the branchial cartilages, and then continues
along the internal side of the ramus of the lower jaw, giving off a

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY 213

branch to the lip. The second branch, the External Inferior
Maxillary, E. I. M., PL 9, runs along the anterior side of the
pterygoid and is distributed to the outer surface of the ramus
of the lower jaw. A third branch, the Orbito-Nasal, O. K,
PI. 9, runs along the lower border of the temporal muscle be-
tween it and the masseter muscle; passing around the dorso-
median side of the eye it gives off branches to the muscles of the
orbit, and then goes to the nasal fossa, where it divides into two
branches, one on each side. Two small branches pass to the
temporal muscle. Another branch of considerable size is the
Ophthalmic, Oph., PI. 9, which arises in common with the
other branches of the internal carotid and runs nearly parallel
with its distal part to be distributed to the eye. Sometimes the
ophthalmic sends branches to the nasal capsule.

Just as the internal carotid pierces the parasphenoid it gives
off a branch at nearly a right angle, the Cerebral Carotid,
C. C, PL 9, which passes to the ventral side of the brain where
it divides into an anterior and a posterior branch. The anterior
continues along the ventral surface of the cerebral hemisphere
of the same side, ending in a. number of fine branches. The pos-
terior branch runs diagonally candad and unites with its fellow
from the other side to form the Basilar Artery, Bs., PL 9, and
then runs along the ventral side of the medulla, giving off
branches at right angles to its course. The two largest of these,
Au., PL 9, pass one on either side to the ear.

The Vertebral Artery, Vert., PL 9, arises from the root
of the aorta, runs cephalad to the parasphenoid, where it divides
into two branches, one running towards the median plane, the
other away from the median plane. The latter again divides
into three small branches, a posterior and a lateral branch going
to the roof of the mouth and an anterior branch to the side of
the medulla. The former branch runs along the spinal column
dorsal to the lateral processes.

The Pulmonary Artery, P., PL 9, and fig. 1, PL 10, arises
from the third efferent branchial artery between the point where
the second efferent artery joins it and where the anastomosing
branch from the first efferent enters. It gives off a few small

214: BULLETIN OF THE UNIVERSITY OF WISCONSIN.

branches to the shoulder, one, Ps., PI. 0, going to the muscles of
the scapula and one, Pb., PL 9, to the cucullaris muscle ; from
here it continues along the ventral surface of the buccal cavity
giving off one or two branches to it, a branch to the oesophagus,
P. oe., PL 9, and then proceeds along the dorsal side of the lung
giving off short branches at right angles to its course.

The External Carotid Artery, E. C, PL 9, and fig. 1, PL
10, arises from the first efferent branchial ; it also receives a
number of small anastomosing branches from the first afferent
branchial artery which accompany it as far as the sternohyoid
muscle, which it supplies with a branch. From here it contin-
ues cephalad along the medio-dorsal surface of the digastric
muscle closely applied to the hyoid arch, giving off a branch to
the geniohyoid and mylohyoid muscles and then anastomoses
with its fellow from the other side at the insertion of the digas-
tric muscle into the lower jaw.

The Dorsal Aorta, A. O., PL 9, is formed by the union of
the two aortic roots and runs along the ventral surface of the
vertebral column. It is the main trunk of the arterial system
and gives off numerous branches as it passes backwards through
the abdominal cavity.

The Subclavian, Sbc, PL 9, and fig. 2, PL 10, arises from
the aorta about 5 mm posterior to the union of the aortic roots,
runs outward between the external oblique and erector spinae
muscles, makes a slight turn dorsad and continues along the
ventral surface of the scapula. JSTear the glenoid fossa the con-
tinuation of the subclavian, now called the Axillary- Artery',
gives off a branch which may be called the Thyroid Axis, T. A.,
fig. 2, PL 10. This almost immediately gives off a branch, Ta.,
fig. 2, PL 10, which enters the anconeus muscle and breaks up
into three smaller branches. The most anterior, T. a. c, fig. 2,
PL 10, passes between the anconeus and the humero antibrachia-
lis inferior muscles across the head of the ulna, along the surface
of the extensor digitorum communis to the first digit. The mid-
dle branch, T. a. b., fig. 2, PL 10, runs along between the head
of the radius and the ulna to the last digit. The smallest and
most posterior branch, T. a. a., fig. 2,' PL 10, goes to the ancon-

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 215

ens. The main portion of the thyroid axis, Tb., fig. 2, PL 10,
runs across the head of the humerus into the procoro humeralis
giving off several branches which supply this muscle, the cucul-
laris and the antibrachialis inferior. The latissimus dorsi may
receive its blood supply from this artery or from T. a. a.

The Cutaneous Artery, Cu., PI. 9, and fig. 2, PI. 10, arises
from the axillary and runs across the ventral surface of the
coracoid ; a little posterior to the glenoid fossa it gives off two
branches, one, Ca., fig. 2, PL 10, accompanies the brachialis
around the upper part of the shaft of the humerus and continues
between the coraco branchialis longus and the humero anti-
brachialis inferior. Sometimes this branch arises directly from
the axillary artery. The other branch, Cu. a., fig. 2, PL 10, of
the cutaneous goes to the pectoral muscles, while the cutaneous
itself, Cu., PL 9, passing candad, pierces the body wall and runs
along its inner surface external to the linea alba anastomosing
with the intercostals and the epigastric.

The continuation of the axillary, the Brachial Aeteey, Br.,
fig. 2, PL 10, passes around the upper part of the shaft of the
humerus to its anterior side, running between the extensor carpi
radialis and ulnaris muscles ; passing between the radius and
ulna it crosses to the outside of the forearm ventral to the ex-
tensor digitorum communis. Just proximal to the carpus the
brachial gives off four branches; one, Br. a., fig. 2, PL 10, to the
flexor carpi radialis, which is continued to the outside of the
first digit ; one, Br. b., fig. 2, PL 10, to the flexor carpi ulnaris,
which continues to the fourth digit ; one to the flexor digitorum
communis and one to the extensor carpi ulnaris. The brachial
is continued as the Cubital Aetery, wThich runs between the
cartilages of the carpus to the dorsal side of the hand, where it
breaks up into three branches. The first of these goes to the ad-
jacent sides of the first and second digits, the second goes to the
adjacent sides of the second and third digits, the third goes to
the adjacent sides of the third and fourth digits.

The next large artery arising from the dorsal aorta is the
Gastric, G., PL 9. It runs candad to the stomach on which,
a little anterior to the center, it divides into two branches, one

216 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

going to the right side, the other to the left. Both branches sub-
divide to supply this organ and in addition to this the left branch
gives off one or two branches to the spleen, Sp., PI. 9.

The Coeliaco-Mesenteric, Coe. M., PI. 9, arises from the
dorsal aorta near the center of the abdominal cavity and runs
out at right angles to the aorta through the pancreas, where it di-
vides into three main branches. The first of these branches runs
cephalad through the anterior lobe of the pancreas dividing into
two smaller branches, one containing anterior, as the Splenic,
Sp'., PL 9, to supply the spleen, the other runs out at nearly a
right-angle to the stomach ; this is the Coronary, Cor., PI. 9.
The second branch is the Hepatic, Hp., PL 9, which supplies
the liver and the gall bladder. The third branch goes to the in-
testine.

The Inferior Mesenteric Arteries, I. M., PL 9, sometimes
as many as twenty in number, arise from the aorta at varying
intervals and run to the intestine, dividing, and as a .rule, anas-
tomosing before they reach it, forming a sort of discontinuous
vessel along the attached border of the intestine. From this,
short semi-circular arteries arise which pass to the wall of the
intestine.

In the male, nine to eleven Spermatic Arteries, Spr., PL 9.
arise on each side from the dorsal aorta and enter the testis. In
the female numerous minute arteries go to the fallopian tubes
and ovaries. The kidneys receive also a variable number of
Renal Arteries, K., PL 9, which arise from the aorta.

Throughout the entire course of the aorta short vessels arise
at regular intervals from its dorsal side, corresponding in num-
ber to the vertebrae ; these run dorsad at right angles to the aorta
and divide into two branches, one for each side. Each branch
runs outwards between the oblique muscles, to which they give
off small branches, and at their distal end anastomose with the
cutaneous and epigastric. The name Intercostal Arteries,
Icls., PL 9, may be given to these vessels. Between the inter-
costals, dorsal to the lateral processes of the vertebrae, lie anas-
tomosing branches, Anas., PL 9, which are continuous with the
vertebral.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 217

The Iliac Artery, II., PI. 9, and fig. 3, PI. 10, arises from
the aorta just anterior to the posterior extremity. It runs out-
ward and backward along the inner surface of the body wall un-
til it reaches a point directly above the ischium, where it divides
into three main branches. The most anterior, the Epigastric
Artery, Epi., PI. 9, and fig. 3, PL 10, runs cephalad and anas-
tomoses with the cutaneous ; it gives off a small branch, Epi. R.,
fig. 3, PI. 10, to the rectus femoris and one to the body wall,
Epi. B., fig. 3, PI. 10. The middle and main branch is the
Femoral Artery, Fi\, PI. 9, and fig. 3, PL 10, which directly
continues the iliac. It crosses the ventral surface of the ischium
and at its posterior border gives off a branch which immediately
divides into three small branches. The most anterior of these,
Er. c, fig. 3, PL 10, runs around the head of the femur and con-
tinues between the rectus femoris and the sartorius ; it breaks
up in the flexor digitorum communis and sends a branch to the
first digit. The second of these three branches, Fr. b., fig. 3,
PL 10, runs under the rectus femoris and continues beneath the
skin of the fore leg to the last digit. The third and most pos-
terior branch, Fr. a., fig. 3, PL 10, goes to the sacro-plantaris
muscle.

The femoral itself continues along the postero-dorsal surface
of the upper half of the gracilis, crosses the femur diagonally to
its anterior surface and continues between the gracilis and sar-
torius muscles. On the inner surface of the fore leg, between
the tibia and fibula, it gives off several branches, one to the flexor
tarsi tibialis, C. a., fig. 3, PL 10, which is continued to the first
digit, one to the flexor tarsi fibularis, which is continued to the
last digit, C. b., fig. 3, PL 10, one to the flexor and one to the
extensor digitorum communis. The femoral then runs between
the cartilages of the tarsus to the dorsal side of the foot, where
it breaks up into three branches. The first of these goes to the
adjacent sides of the first and second digits, the second to the ad-
jacent sides of the second and third digits, and the third goes to
the adjacent sides of the third and fourth digits.

The third branch of the iliac, the Vesical Artery, Vs., PL
9, Vsc, fig. 3, PL 10, arises just before the iliac pierces the body

218 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

wall. It runs along the ventral surface of the body wall to the
bladder, where it, together with its fellow from the opposite side,
gives off three branches to that organ. One of these branches
sends a short twig to the posterior part of the intestine. The
vesical then proceeds to the cloaca, Vs. GL, fig. 3, PL 10, where
it breaks up. At about the center of the vesical artery two
branches are given off; one, Vs. X, fig. 3, PI. 10, passes cephalad
to the muscles on the ventral surface of the ilium, the other runs
caudad to the cloaca, Vs. an., fig. 3, PL 10.

Just posterior to the anal gland the aorta enters the haemal
arches of the candal vertebrae and continues to their end as the
Caudal Aorta, Ca. A., PL 9, giving off branches to the muscles
of the tail. At the anal gland the aorta gives off two branches,
one, GL, PL 9, on each side to the anal gland, and one, M., PL 9,
to the muscles of the body wall.

THE VEINS.

The venous, system of Necturus is exceedingly interesting,
showing as it does points of resemblance to that of the Dipnoi
on the one hand, and the higher Amphibia on the other. I
would call special attention to the sinus between the postcaval
vein and the Sinus Venosus; the communication between the
posterior cardinals and the postcaval; the anastomosis between
the posterior cardinals and the renal portal, — a condition which,
it seems to me, is intermediate between that of Protopterus an-
nectens and Salamandra maculosa. The constant presence of
the anastomoses between the two sets of gastric veins is also quite
conspicuous.

For convenience the venous system will be described under
three heads:

1. RENAL PORTAL.

2. HEPATIC PORTAL.

3. SYSTEMIC VEINS.

In each case the description will be begun with the distal ves-
sels and followed towards the heart.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 219

RENAL PORTAL.

The Eenal Portal system is formed by the bifurcation of the
Caudal Vein, C., PI. 11. This arises at the end of the tail
and runs in the haemal arches of the caudal vertebrae ventral to
the caudal aorta. Just posterior to the cloaca the caudal vein
bifurcates, each branch passing along the outer side of the cor-
responding kidney and giving off numerous vessels, Venae Ad-
vehentes, V. Adv., PL 11, into these organs. Into the renal
portal open the veins from the posterior extremity.

Each of the four digits of the foot has two veins, one on either
side; these two veins usually unite and form short and some-
what larger vessels, which join to form a still larger trunk on the
dorsum of the foot. This latter vessel runs across the distal end
of the extensor digitorum muscles near the proximal end of the
digits. This transverse vein receives also a number of small
vessels which come from the tarsus. From the outside of the
foot this vein is continued towards the body as the Posterior
Tibial Vein, Fbl., PL 11, which courses upwards, and near the
knee joint it bends gradually and passes over the knee to the
flexor surface of the leg. Above the knee it is continued as the
Femoral Vein" (Sciatic?), Sci., PL 11; this passes over the
hip joint and unites with the Pelvic Vein, Pel., PL 11, about
10 mm from the point of union of the latter and the renal
portal.

I am aware that this differs from the usual description of the
veins in Amphibia. Most authors describe the femoral as divid-
ing into two branches, a pelvic and iliac; but no such division
could be made out in any of the specimens studied. The angle
of union between the femoral and pelvic and the size of the pel-
vic precludes, it seems to me, such description.

Just below the knee the posterior tibial receives a branch
which comes from the median side of the leg. Midway between
the knee and the hip the femoral receives a considerable branch
from the ventral side of the thigh and from about the knee joint.
Just before the femoral joins the pelvic vein it receives two small

220 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

branches ; one from about the cloaca, the other from the anterior
region of the thigh.

The two renal portals are connected by the Pelvic Veins, Pel.,
PI. 11, which unite in the mid- ventral line of the body to form
the Abdominal Vein, Abd., PI. 11. The Pelvic Veins, Pel.,
PI. 11, unite with the renal portal near the middle of the kidney.
Prom this point of union each pelvic vein runs along the inner
side of the body wall until it is joined by the femoral; it also re-
ceives a number of small branches from the muscles of the back.
After the femoral has joined it, the pelvic vein runs anteriorly
towards the point of union with its fellow from the opposite
side, where, as already mentioned, they form the Abdominal
Vein, Abd., PL 11.

From its j)lace of origin the abdominal vein runs through the
ventral mesentery and the posterior part of the liver to join the
hepatic portal. The abdominal vein receives close to the union
of the two pelvic veins a small branch which comes from the anal
gland and cloaca, A., PI. 11. In its .course through the ventral
mesentery it receives the Cystic Veins, Cys., PI. 11 ; these are
usually two in number. It also receives several small veins
from the body walls. The abdominal vein enters the liver at
the fissure in its posterior border. In its course through the
liver it receives branches from the liver substance; the largest
of these comes from the left side of the liver.

the hepatic portal.

The Hepatic Portal, H. P., PI. 11, is formed on the dorsal
surface of the liver by the union of the mesenteric, gastric,
splenic and abdominal veins. The Mesenteric Vein, Mes.,
PI. 11, arises by from twelve to fifteen branches from the whole
length of the intestine ; occasionally at its distal end it receives
a few small branches from about the cloaca. For the greater
part of its course it is situated in the mesentery; the anterior
portion, however, passes through the pancreas in order that it
may reach the dorsal side of the liver. The anterior three
branches from the intestine to the mesenteric vein are larger

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 221

than the other branches and do not join it until after it has en-
tered the pancreas.

The gastric vein arises from the posterior third' of the stomach
by two branches ; one on the dorsal and one on the ventral side.
These branches unite at the pylorus and form the Gastric
Vein, Gv., PL 11, which immediately enters that lobe of the
pancreas which is closely applied to the intestine just posterior
to the stomach. As it passes through the pancreas it receives
small branches from the pancreas itself and the adjacent part of
the intestine ; it continues in the pancreas until it joins the
mesenteric vein on the dorsal surface of the liver.

About 6 mm anterior to the junction of the mesenteric and
gastric, the trunk thus formed is joined by the Splenic Vein,
Sp., PI. 11. This vessel arises at the anterior end of the spleen,
and in its course along the ventral surface of that organ receives
many small branches from it. It is also joined by from two to
four veins which bring blood from the dorsal portion of the an-
terior two-thirds of the stomach. The more anterior of these
veins are smaller than those which come from the central region
of the stomach. In two specimens a large vein was found run-
ning dorsally from the spleen, and, passing to the median side
of the left lung, it joined the left posterior cardinal.

Just beyond the enlargement formed by the union of the
mesenteric, gastric and splenic veins the Abdominal Vein, Abd.,
PI. 11, usually joins the hepatic portal ; in other cases it empties
into the enlargement itself.

The Hepatic Portal, H. P., PI. 11, after being formed in
the manner already described, runs anteriorly at the bottom of
the fissure on the dorsal side of the liver. It becomes smaller
and smaller, on account of the numerous branches which it gives
off, and finally, at the anterior end of the liver, breaks up into
small branches. About 20 mm from the anterior end of the
liver a variable number of veins, two to four in number, coming
from the antero-ventral portion of the stomach, G., PL 11, join
the hepatic portal. The most posterior of these veins is the
largest, and is mainly formed by a branch which can be traced
posteriorly along the ventral side of the stomach to form an

222 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

anastomosis with the ventral branch of the gastric vein, Gv.,
PL 11.

From the median line of the abdominal wall the hepatic por-
tal receives from twelve to fifteen veins. Each of these veins is
formed by two branches which, coming from either side in the
septa of the abdominal muscles, unite at the mid-ventral line.
These veins run from the body wall to the liver in the ventral
mesentery, in which they often form an open network, each ves-
sel being joined by a transverse branch, or they may unite so that
not more than seven or eight veins enter the liver. Within the
liver they join, as has been said, the branches of the hepatic por-
tal.

All the blood which is brought to the liver by the hepatic por-
tal and abdominal veins is collected by the Hepatic Veins, H.,
PI. 11, which empty into the postcaval vein at different points
along its course through the liver. The hepatic veins vary
greatly in size and have no fixed point of entrance into the post-
caval. Two of the hepatic veins are much larger than the others
and have a fairly constant point of union with the postcaval.
The larger of these two veins arises at the posterior end of the
liver and joins the postcaval near the center of the liver. The
other is not as constant in its course or place of origin ; in the
majority of the specimens examined it took its origin near the
posterior border of the liver and ran along the left margin of the
liver, receiving many small branches, and finally united with
the postcaval at the anterior end of the liver. The first of these
two hepatic veins is shown in PI. 11, but for the sake of clearness
the last is omitted.

SYSTEMIC VELNS.

The Posterior Vena Cava, or Postcaval Vein, P. C, PI.
11, is the largest vein in the body; it runs anteriorly between
the kidneys receiving through the Venae Reheventes,'V. Rev.,
PL 11, the blood which has been brought to these organs by
the venae advehentes, and a few veins from the muscles of the
back. From the kidneys it is continued just ventral to the
aorta until it is from 20 to 50 mm anterior to the posterior

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 223

border of the liver ; it then bends ventrally from the aorta and
enters the liver somewhat to the left of the median line. In the
liver it continues anteriorly until it reaches its anterior margin
where it divides into the Hepatic Sinus, H. S., PI. 11, which,
after being joined by the Ducts of Cuvier, D. C, PL 11,
empties into the Sinus Venosus.

In the female the posterior vena cava receives on each side
as it passes between the ovaries from fourteen to twenty Ovarian-
Veins, O., PL 11. The number differs not only in different
specimens, but also on the different sides of the same specimens.
These veins are small and very tortuous. Usually two or three
form a small group and unite just before they enter the post-
caval. They vary in length as well as in size ; those from the
center of the ovaries are about 10 mm long, while those from the
ends are not more than 5 mm in length. The adjacent groups
of veins are connected with each other by small cross branches
near the ovaries.

In the male five, rarely four or six large, and several small,
Spermatic Veins run from each testis into the postcaval as it
passes between them.

On the convex side of the bend where the posterior vena cava
leaves the dorsal wall of the body cavity to enter the liver, it
is joined by a vessel which branches like a Y, and connects it
with each of the posterior cardinal veins, Y., PL 11.

The Posterior Cardinal Veins, P. C, PL 11, arise near
the central part of the body on each side of the aorta. They
run anteriorly until near the Duct of Cuvier; here they bend
laterally and empty into these vessels at their distal end. At
their caudal end the posterior cardinals are connected with the
renal portal by means of muscular branches which come from
the back. Each muscular vessel in this region of the back, as
soon as it penetrates the body wall divides into two branches,
one of which passes anteriorly, the other posteriorly. These
branches anastomose with each other and eventually with the
posterior cardinal in front and the renal portal behind. The
letters R. P., in Plate 11 are opposite the branches which form
the anastomosis. This connection between the posterior cardi-

224 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

nals and the renal portal is more marked in the female than
in the male. Besides the muscular vessels taking part in the
anastomosis there are others which join the posterior cardinal
along nearly its entire length; these veins are about 6 mm
apart and come from between the vertebrae. Each posterior
cardinal communicates with the posterior vena cava on the con-
vex side of the bend where it leaves the dorsal body wall. Some-
times the communicating vessels are separate and enter the post-
caval near together. More often the veins from the posterior
cardinals unite before they enter the postcaval as already de-
scribed, V., PI. 11.

The Fallopian Veins, F., PL 11, are small vessels which
run in a wavy course along the ventral side of the anterior part
of each fallopian tube. At the anterior end of each tube the
vein joins the posterior cardinal of that side. Besides this prin-
cipal vein there are numerous small vessels which pass from the
walls of the fallopian tubes to the posterior cardinal veins, Z.,
PL 11. Opening into the fallopian vein, near its junction with
the posterior cardinal, are two or more small branches which
come from about the ostium abdominale of the oviducts.

Taking up now the veins that return the blood from the head,
it will be seen that there are three: the internal jugular, the
external jugular, and the lingual, on each side.

The Internal Jugular, Ji., PL 11, is formed principally by
the union of two veins ; one of these comes from the roof of the
mouth, the other from the brain case, the upper part of the spinal
column and the dorsal wall of the pharynx. From the place of
union of these two branches, the internal jugular runs poster-
iorly to unite with the external jugular about 7 mm anterior
to the junction of latter with the Duct of Cuvier.

The External Jugular, Je., PL 11, receives branches from
the external parts of the head and from the ventral wall of the
mouth. It is formed for the most part by the union of two
veins. One of these, the Naso-JOrbital Vein, N. Or., PL 11,
runs across the masseter muscle, receiving branches from the
antero-dorsal part of the head and from the eye. The other

MILLER— CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 225

of these branches, the Submaxillary Vein, Sbm., PL 11, is
formed by branches from the antero-ventral wall of the oral cav-
ity and the anterior portion of the lower jaw. The vessel thus
formed passes along the ventral edge of the submaxillary bone,
receiving in its course a number of branches from the ventral
side of the head and from about the gill arches. About 4 mm
posterior to the angle of the mouth this vessel unites with the
naso-orbital to form the external jugular vein. From this point
the external jugular vein runs posteriorly between the digastric
and masseter muscles. In this part of its course the external
jugular is just beneath, and closely applied to, the skin ; it ap-
pears here as a sinus, the Jugular Sinus, J. S., PI. 11, and re-
ceives numerous branches from the lateral and dorsal portions
of the head ; the largest of these branches is formed by the union
of small branches from the temporal and masseter muscles.
Just where the gills join the branchial cartilages this sinus runs
ventrally for a short distance, then posteriorly and empties into
the Duct of Cuvier external to the place where the subclavian
vein enters. Just before making this last turn it is joined by
the internal jugular.

The Lingual Vein, Li., PI. 11, is formed not only by
branches from the tongue, but also from the digastric, the cera-
tohyoid and the geniohyoid muscles. Prom its origin it runs
posteriorly along the gill arches until it reaches a point lateral
to the Duct of Cuvier; it then turns towards the median line
and joins the subclavian vein just before it empties into the
Duct of Cuvier.

The Lateral Vein, L., PL, 11, arise near the median region
of the body wall and run anteriorly along the lateral line. Just
external to the Duct of Cuvier it turns from its position beneath
the skin and, passing towards the median line, joins the Duct
of Cuvier external to the entrance of the posterior cardinal.
The lateral veins are formed from branches which join them at
right angles from the septa in the abdominal muscles. These
branches may form an anastomosis with the veins which pass
into the liver, along the ventral mesentery, from the body wall.

226 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

VEINS OF THE ARM.

Beginning at the distal end we find that each digit has two
veins, one on each side ; these two veins usually unite and form
single vessels, these in turn form a transverse vein on the dor-
sal surface of the hand which passes across the extensor digi-
torum communis near the proximal end of the digits. Near the
middle of the hand this vein turns toward the body and runs
as the Radial Vein, Rdl., PI. 11, as far as the elbow; here it
is joined by a vein from the opposite side of the arm, the Ulnar
Vein, W., PI. 11. By the junction of the radial and ulnar veins
there is formed the Brachial Vein, Hum., PL 11 ; this runs
along the arm between the biceps and triceps muscles, and, pass-
ing over the glenoid fossa to the lateral side, continues to a
point which is anterior and ventral to the Duct of Cuvier. Here
it is joined by the lingual vein and empties directly into the
Duct of Cuvier. Between the glenoid fossa and the Duct of
Cuvier the vein is called the Subclavian, Sbc, PI. 11. Just
above the glenoid fossa the subclavian receives branches which
come from the anterior part of the arm and from the muscles
about the scapula.

PULMONARY VEINS.

The Pulmonary Veins, P., PI. 11, are two in number, one
from each lung. They run along the latero-ventral side of the
lung and unite in the mid-line anterior to the union of the two
lungs. From this point of union the now single pulmonary
vein runs anteriorly towards the heart, and passing to the dor-
sal side of the two arms of the Hepatic Sinus it usually con-
tinues in the wall of the left arm of the sinus until it finally
opens into the left atrium of the heart.

Plate 9.

Description of Plate 9.

Vascular System of Necturus maculatus. .a

The arterial system of Necturus maculatus; diagram some-
what less than the natural size of the animal. The dissection
was made from the ventral side. The ventral aorta and its
branches are represented by shaded vessels ; the systemic ar-
teries as solid vessels. The left arm and leg have been omitted
from the diagram, also a few of the smaller vessels described in
the text, for the sake of clearness.

A. B. Anastomosing branch between

G.

Gastric.

first and third efferent vessels.

Gl.

Branch of caudal aorta to anal

A. B. I. First afferent branchial artery.

gland.

'A. B. II. Second afferent branchial artery.

Hp.

Hepatic.

A. B. III. Third afferent branchial artery.

I. C.

Internal carotid.

Anas. Anastomosing branch between

I. Cls.

Intercostals.

intercostals and vertebral.

I. I. M.

Internal inferior maxillary.

A. O. Dorsal aorta.

11.

Iliac.

An. Auditory.

I. M.

Inferior mesenteries.

Br. Brachial.

K.

Renal.

Bs. Basilar.

M.

Muscular branch of caudal aorta

Ca. Caudal Aorta.

O. N.

Orbito-nasal.

C. C. Cerebral carotid.

Oph.

Ophthalmic.

Coe. M. Coeliaco— mesenteric.

P.

Pulmonary.

Cor. Coronary.

P. b.

Muscular branch of pulmonary.

Cu. Cutaneous.

P. 0. E.

Oesophageal branch of pul-

C. V. Trunk formed by the union of

monary.

second and third efferent ves-

P. s.

Muscular branch from pulmon-

sels.

ary.

E. B. I. First efferent branchial artery.

R. A.

Aortic root.

E. B. II. Second efferent branchial artery.

Sbc.

Subclavian.

E. B. III. Third efferent branchial artery.

Sp.

Splenic branch of gastric.

E. B. A. Branch to second afferent artery.

Sp'.

Splenic.

E. C. External carotid.

Sp. r.

Spermatics.

E. I. M. External inferior maxillary.

Tr.

Truncus arteriosus.

Epi. Epigastric.

Vert.

Vertebral.

Fr. Femoral.

Vs.

Vesical.

BULL. UNIV. WiS.. SCI. SER.

VOL. 2, PL. -J.

Plate 10.

Description of Plate 10.

Vascular System of Necturus maculatus.

Fig.

1. Afferent and efferent vessels on a larger scale than in
Plate 9. The capillary connection between the two
is omitted.

A. B. Anastomosing branch between

first and third efferent vessels.

A. B. I. First afferent branchial artery.

A. B. II. Second afferent branchial artery.

A. B. III. Third afferent branchial artery.

A. O. Dorsal aorta.

C. V. Union of second and third effer-
ent vessels.
E. B. I. First efferent branchial artery.

E. B. II. Second efferent branchial artery
E. B. III. Third efferent branchial artery.
E. B. a. Branch to second afferent artery.
E. C. External carotid.
I. C. Internal carotid.

P. Pulmonary.
R. A. Aortic root.
T. R. Truncus arteriosus.

Pig.

2. Arteries of the arm and hand.

Br. Brachial.
Br. a. Branch to flexor carpi radials

and first digit.
Br. "b. Branch to flexor carpi ulnaris

and last digit.
C. a. Branch of cutaneous to upper
part of arm. ■, -,

Cu. Cutaneous.
Cu. a. Branch of cutaneous to pectoral
muscles.

T. A. Thyroid axis.

T. a. Muscular branch of Thyroid axis.
T. a. a. Branch of T. a. to anconeus.
T. a. b. Branch of T. a. to last digit.
T. a. c. Branch of T. a. to first digit.
T. b. Muscular branch to procoro hu-
meralis, cucularis and anti-
brachialis.

Fig. 3.

Arteries of the leg and foot.

C. A. Branch to flexor tarsi tibialis

and first digit.
C. B. Branch to flexor tarsi fibularis

and last digit.
Epi. Epigastric.
Epi. B. Branch of epigastric to body

wall.
Epi. R. Branch of epigastric to rectus
femoris.
Fr. Femoral.

Fr. a.

Muscular branch of femoral.

Fr. b.

Branch to last digit.

Fr. c.

Branch to flexor digitorum com

munis and first digit.

11.

Iliac.

Vs. an.

Branch to cloaca.

Vs. c.

Vesical.

Vs. gl.

Branch to cloaca.

Vs. I.

Muscular branch.

BULL. UNIV. WIS., SCI. SER.

VOL. 2, PL. 10.

Plate 11.

Description of Plate 11.

Vascular System of Necturus maculatus.

The venous system of Necturus maculatus. The diagram is
made from a ventral dissection. The liver has been turned over
as far to the right as possible. The left arm and hand and the
right lee* and foot are shown. A few of the small veins and one
of the large hepatic veins have been omitted for the sake of clear-
ness.

A. Anal.

N.Or. Naso-orbital.

Abd. AbdominaL

0. Ovarian.

C. Caudal.

P. Pulmonary.

C. B. Branch of caudal forming

Renal

P. C. Posterior cardinal.

Portal.

Pel. Pelvic.

Cys. Cystic.

Rdl. Radial.

D. C. Duct of Cuvier.

R. P. Renal Portal; letters placed just

F. Fallopian.

above anastomosis with poste-

Fbl. Tibial.

rior cardinal.

G. Branches from stomach to hepatic.

Sbc. Subclavian.

Gv. Gastric.

Sbm. Submaxillary.

H. Hepatic.

Sci. Femoral.

H. P. Hepatic Portal.

Sp. Splenic.

H. S. Hepatic Sinus.

S. V. Sinus Venosus.

Hum. Humeral.

V. Adv. Venae advehentes.

Je. External jugular.

V. Rev. Venae reheventes.

Ji. Internal jugular.

W. Ulnar.

Js. Jugular Sinus.

Y. Anastomosing branch between pos-

L. Lateral.

terior cardinal and posteaval.

Li. Lingual.

Z. Branches from fallopian tube to

Mes. Mesenteric.

posterior cardinal.

♦The single star in the upper part of the diagram indicates the position of the pul-
monary vein in the Sinus Venosus. The two stars in the lower part of the diagram
indicate the cut pelvic vein, made necessary by the reflection to the right of the liver.

BULL. UNIV. WIS., SCI. SER.

VOL. 2, PL. 11.

VRev

VAdv

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 227

THE BRAIN OF Necturus ma.cula.tus.

The brain of Necturus is long in proportion to its width and
depth. Its greatest length, measuring from the superficial ori-
gin of the olfactory nerves to the beginning of the spinal cord
is about 230 mm; its greatest breadth, measuring across the
caudal part of the prosencephalon is about 50 mm; its greatest
depth taken through the thalamencephalon at the origin of the
pituitary body is about 22 mm.

Viewed from the dorsal side, PI. 12, and enumerating from
anterior to posterior we see that the brain is composed of the
olfactory lobes which pass without any sharp line of demarca-
tion into the hemispheres of the prosencephalon; back of the
prosencephalon, as an undivided body, lie the thalamencephalon
and mesencephalon and pineal gland ; then, as a caudal contin-
uation of the mesencephalon, we see the epencephalon which
forms a rudimentary roof of the fourth ventricle; and finally
sharply separated from the mesencephalon we can see the nieten-
cephalon or medulla oblongata.

In a ventral view, PI. 13, we see the following parts : Lying
farthest anteriorly are the olfactory lobes and cerebral hemi-
spheres, then the thalamencephalon with its broad pituitary body
which covers the mesencephalon except on the lateral sides, and
finally we have the metencephalon.

In a lateral view we notice that the brain vesicles lie in front
of one another and that there is but an insignificant departure
from the straight and unflexed condition of the embryonic
brain. This is true of most of the aquatic Urodeles as Fish
has noted.

228 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

GROSS ANATOMY.

Prosencephalon. The prosencephalon is composed of two
rounded cylindrical bodies which are sharply separated by a
longitudinal fissure as far as the anterior closing plate. The
cylindrical bodies are about 8.8 mm long and about 2.5 mm in
diameter; they are slightly concave along their lateral border
and straight along their median side, and at their posterior end
they are more diverging than in front. Measured dorso-ven-
trally they are thickest at their posterior end and gradually
narrow towards the origin of the olfactory nerve. In cross sec-
tion their median surfaces are shown to be flattened while their
outer are convex ; the union of the two surfaces is marked by
a sharp angle. As there is no sharp line of demarcation between
the olfactory lobes and the hemispheres, for convenience of de-
scription they will be considered together ; and thus each hemi-
sphere is to be considered as composed of the olfactory lobe and
the hemisphere proper.

On the other hand, in Bana and in the Chelonia the olfactory
lobes can be readily distinguished from the cerebral hemispheres.
In all these cases, however, the surface of the prosencephalon
is perfectly smooth and is without convolutions.

Concerning the question as to whether the olfactory portion
deserves setting apart as a separate segment there is at pres-
ent a variance of opinion.

Steiner, working from a physiological standpoint, argues from
experiments carried on in the shark, that the prosencephalon
of every vertebrate has developed phylogenetically out of the
olfactory organs.

Thalamencephalon and Mesencephalon. These two are
united into a short cylindrical body with no sharp line of de-
marcation between them. This body is flattened or even slight-
ly concave on the dorsal and ventral surfaces. These surfaces,
with the exception of the median groove on the dorsal side, are
all unbroken, there being no elevations or other external indi-
cations to mark the position of the optic lobes in the mesenceph-
alon. In this respect the brain of the Necturus differs greatly

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 229

from that of the Dipnoans on the one hand and from that of
the Rana on the other. In both the latter cases we have the
optic lobes well developed.

Anteriorly, it is sharply separated from the prosencephalon
by a deep groove on the dorsal surface and a shallow one on
the ventral; posteriorly, it is continued dorsally by the epen-
cephalon or the cerebellum and ventrally by the metencephalon
or the medulla oblongata. Measuring from the base of the
pineal gland to the cerebellum it is about 5.8 mm long, and
measured laterally it is about 3.1 mm in diameter. In cross
section it will be noticed that the walls are very thick laterally,
while dorsally they grow thinner until in the median line of
the thalamencephalon there is only a thin layer of cells pres-
ent. A cavity, the third ventricle and the Aqueduct of Sylvius,
extends through the thalamencephalon and the mesencephalon
and is of the same size throughout, except where the infundibu-
lum joins it and anteriorly where it connects with the lateral
ventricles of the cerebral hemispheres. At the place where the
cavity of the infundibulum joins the thalamencephalon there
is a V-shaped depression in the floor. At the anterior part of
the cavity there is a gradual widening toward the foramen of
Monroe. The relation of the pineal gland, pituitary body, optic
and occulomotor nerves to these segments of the brain will be
considered later.

Epencephalon. This is a short ledge which forms part of the
roof of the fourth ventricle. It is thickest in its anterior part
and thins out at the edges. Its general form is convexo-concave,
when viewed from the dorsal side.

In the dorsal view of the brain, PL 12, it will be seen that
the roof of the fourth ventricle extends further posteriorly than
is indicated by Osborn. While he gives the roof as extending
only as far as the superficial origin of the trigeminal, I found
it extending further caudal, as far as the superficial origin of
the facial.

Metencephalon. I consider the metencephalon as a direct
posterior continuation of the ventral part of the mesencephalon,

230 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

for in forms below the mammals we have no pons to mark a di-
viding line.

This is the longest part of the brain, being one and one-half
times as long as the rest of the brain. The metencephalon ex-
tends from the mesencephalon in front to the first pair of spinal
nerves and is of the triangular shape common in the lower ver-
tebrates. From its rounded base at the mesencephalon it grad-
ually narrows toward the spinal cord. On the dorsal surface,
PI. 12, we see a deep triangular fossa, the fourth ventricle,
which is two-thirds the length of the metencephalon, its base
being at the anterior part of the medulla and its apex being
drawn out into a narrow fissure posteriorly. This cavity con-
nects with the Aqueduct of Sylvius anteriorly. Besides the
fossa on the dorsal surface there is a deep median groove which
corresponds to the posterior septum, and on the ventral surface,
one which corresponds to the anterior fissure of the cord.

The 'Pineal Gland. This is well developed in Necturus and
extends forwards between the cerebral hemispheres to near their
center, PI. 12. It is a triangular-shaped body as seen in cross
section, the apex being directed ventrad. Shortly after leaving
the thalamencephalon it extends dorsally, becomes narrower, and
its anterior end is applied against the roof of the brain case.
Serial sections show, however, that it does not penetrate it.

Osborn, judging from his paper on the Amphibian brain,
thinks that the pineal gland does penetrate the cranial roof. I
have not found this to be the case in the specimens I have
studied ; it simply flattens against the roof. The gland is solid,
containing no cavity.

The Pituitary Body. This arises from the postero-ventral
part of the thalamencephalon and extends backwards 5 mm to
near the origin of the Vlllth nerve, PI. 13. After proceeding
a short distance it narrows, but soon widens again, thus forming
a slight enlargement at the posterior end, the hypophysis. The
pituitary body lies on the floor of the brain case and conforms
closely to its irregularities.

The pituitary body is hollow as far as the hypophysis. This
cavity is oval in cross section and as it approaches the hypophysis

MILLER CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 231

gradually narrows dorso-ventrally until it is finally obliterated.
The dorsal wall or roof of the infundibulmn is very thin at the
base of the pituitary body but increases in thickness as it pro-
ceeds posteriorly.

NERVES.

I. Olfactory. These are the most prominent pair of nerves.
They arise directly from the ventrolateral margin of the cor-
responding hemisphere. A sharp line on the dorsal side shows
the place of origin of the nerve, but on the ventral side no sharp
line of demarcation is present. On cross section the nerve is

oval in shape.

In pursuing my work several peculiarities were noticed in
the branching of the olfactory nerves of the brains studied. In
one instance the nerve, a short distance from the olfactory lobe,
broke up rapidly into branches, which ran some distance before
entering the nasal capsule. This brain is the one used in the
model and in the drawings. In another case the right olfactory
nerve divided into two branches almost as soon as it left the
lobe ; but in most cases the nerve ran some distance before break-
ing up into its smaller branches.

II. Optic. This nerve is very small and fragile. It arises
in the ventro-median line of the thalamencephalon just a little
anterior to the posterior ends of the cerebral hemisphere. There
are apparently no elevations or tracts at the place of origin of
the optic nerve, but it seems to rise in conjunction with its fel-
low from the surface of the brain. The nerve runs obliquely
from its place of origin, thus forming an acute angle with its
fellow.

III. Oculo-motor. This nerve arises in the lateral median
line at the extreme anterior part of the mesencephalon. It is
very fragile and is nothing but a thread. It is very easily
broken, often separating from the brain in dissecting away the
meninges of the brain. It runs along the lateral surface of the
brain until a short distance past the posterior ends of the cere-
bral hemisphere when it turns off obliquely to the muscles of

232 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

the eve. It branches before reaching the ophthalmic branch of
the 5th ; the branches passing on either side of this nerve.

IV and VI. Pathetic and Abducent. I consider these two
nerves together because there is a great variance of opinion as
to their presence or absence in the various Amphibia.

Osborn in his discussions of the Amphibian brain claims to
have found both of these nerves in the Necturus, though he fails
to show the Vlth in any of his drawings and to make any definite
statement about either. In his drawings he gives the Vlth nerve
as arising from the roof of the 4th ventricle, at a point which cor-
responds to the cerebellum.

Fish failed to demonstrate the IVth in Desmognathus.
Kingsley failed to find it in the larva Amphiuma, but Mrs. Gage
found it in a very rudimentary condition in the adult Diemycty-
lus.

As to the Vlth nerve Kingsley says it is not found in the
larva Amphiuma; Osborn, as stated at the beginning of this
topic, omits it from his figures ; while Reissner and Ecker de-
scribe it in the Frog, and Fisher finds it in Siredon and Nec-
turus. With these facts in view I retraced my work, studying
carefully my serial sections and the many brains which had
been dissected as well as those isolated by 20 per cent, nitric
acid, and I have come to the conclusion that the IVth nerve
is not present in Necturus, and if the Vlth is, it has no sepa-
rate origin. My reasons for this statement are the following :

1. In serial sections I was unable to find anything that cor-
responded to the IVth nerve at the place where Osborn gives
its origin, i. e., in front of the cerebellum. Xor could I find
anything which would correspond to the origin of the Vlth.

2. Finding that by studying the brain alone I was unable
to find the origin of these nerves in question, I decided to dis-
sect out the muscles of the eye and see if from this I could
trace the nerves. After a careful dissection in which as far
as I could see the nerves remained intact I arrived at the fol-
lowing results: The muscles of the eye are supplied by the

Illrd and by branches of the Ophthalmic division of the Vth.
All six muscles of the eye were supplied by these nerves as well

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 233

as other muscles adjoining. The Opthalmic nerve could be traced
to the Gasserian ganglia as well as the branch in question, but
I could not find, as already stated, a nerve arising from a sep-
arate origin that would correspond to the Vlth, and there were
no nerve fibres that could have arisen from the roof of the fourth
ventricle.

V. Trigeminal. This is one of the largest of the cranial
nerves. The trigeminal arises from the cephalo-lateral angle
of the metencephalon. It runs forward at quite a sharp angle
with the brain and just before it penetrates the brain case it
joins the Gasserian ganglion from which two main branches pass
out, the ophthalmic and maxillo-mandibularis.

VII. Facial. This arises in conjunction with and anterior
to the Vlllth on a line parallel to the Vth and a short dis-
tance caudal. Xear its origin it divides into two main branches,
one of which joins the Gasserian ganglion, the other and larger
continuing with the Vlllth nerve for a short distance and then
separating.

VIII. Auditory. This is a thick and very short nerve, which
shortly after separating from the Vllth divides into two main
branches, which join the auditory vesicle. It extends out at
right angles from the brain and, in its final branching, becomes
like a brush.

IX. Glossopharyngeal. This arises by a single origin on a
line parallel with the Vllth and a short distance posteriorly.
It then proceeds caudal at a sharp angle with the brain for a
short distance and unites with the Vagus.

X. Vagus. This arises from two separate origins about on
a line with each other, and with the IXth at a place opposite
the middle of the fourth ventricle. The posterior root is the
smaller and unites with the anterior root just before the
IXth joins them. The joint root thus formed runs into the
ganglion of the Vagus.

234 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

BIBLIOGRAPHY,

Born, G. "The Plattenmodellirmethode." Arch. f. mik.
Anat. 1883, and Zeit. f. wiss. Mik. 1884.

Eckee, A. "The Anatomy of the Frog." 1889.

Eycleshymee, A. C. "Paraphysis and Epiphysis in Ambly-
stoma." Anat. Anz. Vol. VII.

Eischee, J. G. "Anatomische Abhandlungen uber die Perren-
nibranchiaten und Derotrenien."

Fish, P. A. "The Central Nervous System of Desmognathus
fusca." Jour. Morph. Vol. X. 1895.

Gage, S. H. "Proceedings of American Microscopical So-
ciety." 1892.

Gage, S. P. "The Brain of Diemyctylus viridescens from
Larval to Adult Life, and Comparisons with the Brain of
Amia and Petromyzon. The Wilder Quarter-Century
Book. 1893.

KiisrGSLEY, J. S. "The Head of an Embryo Amphiuma."
Amer. Naturalist. Vol. XXVI.

Orr, H. "The Embryology of the Lizard." Jour, of Morph.
Vol. I. 1887.

Osborn, H. T. "A Contribution to the Internal Structure of
the Amphibian Brain." Jour, of Morph. Vol. II.
1888.

Eeissner, E. "Der Bau des Centralnervensystems der unge-
schwanzten Batrachier." Dorpat. 1864.

Steiner, J. "Die Eunctionen des Centralnervensystems und!
ihre Phylogenese." Braunschweig. 1888.

Wiedersheim, Jx. Elements of Comparative Anatomy of Ver-
tebrates." Parkers' Trans. 1897.

Plate 12.

Description of Plate 12.

The Brain of Necturus maculatus.

Photograph of a model which was enlarged twenty diameters ;
in the plate it is reduced to about six and a quarter diameters.
Dorsal view.

O. L. Olfactory Lobe.

I. Olfactory Nerve.

Pros. Prosencephalon.

II. Optic Nerve.

Thai. Thalamencephalon.

III. Oculo-motor Nerve.

Mes. Mesencephalon.

V, Trigeminal Nerve.

Epen. Epencephalon.

VII. Facial Nerve.

Met. Metencephalon.

VIII. Auditory Nerve.

4th V. Fourth Ventricle.

IX. Glossopharyngeal Nerve

G. g. Gasserian Ganglion.

X. Vagus Nerve.

V. g. Ganglion of the Vagus.

BULL. UNIV. WIS., SCI. SER.

VOL, 2, PL. 12.

O. L.

Pros.

Thai.

Mes.
G. g.

Epen.
4th V.

Met.
V.g.

Plate 13.

Description of Plate 13.

The Brain of Necturus maculatus.

Photograph of a model which was enlarged twenty diameters ;
in the plate it is reduced to about six and a quarter diameters.
Ventral view.

O. L. Olfactory Lobe.
Pros. Prosencephalon.
Thai. Thalamencephalon.

Pt. Pituitary Body.
Met. Mesencephalon.
I. Olfactory Nerve.
II. Optic Nerve.

III. Oculo-motor.

V. Trigeminal Nerve.
VII. Facial Nerve.
VIII. Auditory Nerve.

IX. Glossopharyngeal Nerve.
X. Vagus Nerve.

BULL. UNIV. WiS., SCI. SER.

VOL. 2, PL. 13.

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 235

THE EPITHELIUM OF THE PERITONEAL CAVITY OF THE CAT.

The cats used for the following study varied in age from
six months up to two years. Each peritoneal cavity was exam-
ined with special reference to the epithelium of the central
tendon, suspensory ligament of the liver, mesentery and great
omentum. Each cat was chloroformed and bled thoroughly so
as to lessen the possible chance of blood getting on the surfaces
to be studied. The abdomen of the animal was then carefully
opened and a piece of the omentum, of as large size as possible,
was removed to the silver solution.

The remainder of the omentum was then turned aside, and
a large fold of the mesentery, together with the intestine to
which it was attached, was removed. The intestine was closed
by means of a double ligature previous to removal, and if any
blood-vessel appeared to contain a considerable amount of blood
it was also ligated. The loop of intestine served as a conven-
ient means of handling and protection from mechanical injury
and was not removed until the staining was complete.

In some cases the peritoneal surfaces were stained in situ,
to reduce the risk of injury to a minimum. In other cases the
suspensory ligament and parts of the mesentery were removed
by supporting them on a glass slide and carefully excising a
portion with the scissors. The specimens were then transferred
to the stain, while still on the slide, and floated off.

In all cases some one of the various solutions of nitrate of
silver was used. A slight modification of Dekhuysen's method
proved very satisfactory, giving sharp and clear boundary lines
to the epithelial cells. In a few instances the nuclei were
stained with haematoxylin.

Special effort was made to obtain as large pieces of the mes-
entery, omentum, etc., as possible. The great difficulty with

236 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

such large specimens was that injury was so easily done to themr
thus apparently detracting from their value. Important evi-
dence, however, was furnished in this way as will appear later.

Nearly all the specimens of the mesentery were taken from
that of the small intestine, because much greater delicacy in
handling the material was possible here. Some preparations
were made from the meso-colon ; but as these were found similar
in all respects to those from the mesentery of the small intes-
tine, and as the danger of injury was much greater owing to-
its situation, most of the work was done on the mesentery of
the small intestine.

The Peritoneal Epithelium. All of the epithelium of the
peritoneal cavity which was studied consisted of a simple layer
of flat, polygonal cells, bounded by rather relaxed, wavy lines.
PI. 14, fig. 1, 2, 3. The variation in the size and form of
the individual cells in the same region of the peritoneal cavity
was slight, but between different regions was quite noticeable.
In general it may be said that the cells of the epithelium of
the mesentery were the most uniform both in size and shape.
They were larger than those of the central tendon and suspen-
sory ligament, but smaller than those of the omentum. The
cells of the latter were the largest and most irregular found;
they were narrower in proportion to their length and were
bounded by more undulatory and distinct lines.

The cells of the central tendon, suspensory ligament and dia-
phragm, although smaller than those of the omentum and mes-
entery, resemble them otherwise quite closely. Classified in the
order of their size their order would be: diaphragm, suspen-
sory ligament, central tendon, mesentery, omentum, — the lat-
ter being the largest. If the straightness of the intercellular
lines is taken as a basis the order would be : diaphragm, central
tendon, mesentery, suspensory ligament, omentum, — the latter
having the most wavy lines. This classification has little sig-
nificance, however, for as Schwartz (20) and Muscatello (14)

Note.— In this paper reference to the literature is made by means of number
inclosed in ( ). The titles of the papers or books referred to will be found in
the Bibliography, page 245.

MILLER— CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 237

have shown, the shape of the cells and the condition of relax-
ation of their bounding lines is dependent on tension.

With the increase in age of preparation the appearance of the
epithelium was found to change. Numerous granulations ap-
peared and the nuclei wore seen in clear relief. The stronger
the solution of nitrate of silver used the larger and more nu-
merous were the granules.

Owing to these phenomena it was found advisable to study all
preparations immediately after they had been mounted. In
preparations which had been impregnated with a weak solution
of nitrate of silver (2:1000) these granules were usually absent
•even after being kept for some months. In some specimens nu-
merous cast-off epithelial cells were found, but in no case was
anything at all comparable to Klein's "germinating cells" found.
Stomata. Klein (7) accents the conclusions of v. Reckling-
hausen (19) which he says were reiterated by Ludwig and
Schweigger-Seidel (13), Dybkowsky (4), Schweigger-Seidel
and Dogiel (21), and Bohm (3). Klein himself declares that
"we can only consider those figures as stomata which lie in the
center of radially disposed, relatively large endothelial cells."
"All other indications," he continues, "are very probably only
young cells formed by division of the larger." He also admits
that it is a difficult question to decide whether certain structures
can be called stomata or not.

Ellenberger (5) practically agrees with this view, adding that
"these numerous stomata are bounded by the free ends of the
imbedded nuclei." Ranvier (17), on the contrary, denies the
existence of stomata and regards these structures as nothing else
than "small inter-endothelial spots." Arnold (1), in his earlier
writings speaks of stomata and stigmata; but in his later, he
declares that "stigmata are nothing else than scattered diffusions
of the fluid or semi-fluid inter-cellular substance."

Klein in a later publication than the one mentioned above
(8) and especially in his joint publication with ISToble Smith (9)
goes much farther than any of the previous investigators, not
only as to the classification of stomata, but also regarding the
importance which he ascribes to them. They divide stomata

238 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

into stomata vera and pseudo-stomata. Stomata vera are small
openings at the junction of several epithelial cells. They are
said to be bounded by small cells in the process of division —
the so-called "germinating cells." "These cells when ripe be-
come detached and may at once be absorbed as lymph corpuscles"
(sic).

The character of pseudo-stomata they describe as follows :
"There exist superficial branched cells in the serous membranes
which lie either totally or partially between the endothelium of the
surface, or, as is more commonly the case, only reach the surface
by a process which projects between the superficial endothelium.
* * * * we shall show * * * what great importance must be
ascribed to these freely projecting cell processes; we call them pseudo-
stomata."

These cell processes by budding give rise to single cells, and
in certain pathological conditions cell proliferation takes place
from them. Klein also makes the statement that "in female
frogs, during the spawning season, the endothelial cells lining
the stomata are ciliated" ; a statement which I can not support
and have not found corroborated by anyone.

Although the subject has received much attention from in-
vestigators there still exists a great diversity of opinion as to
what are, and what, are not, stomata; or, to put it differently,
what are pre-formed natural openings and what are artificial.
Even those authors who express a belief in the existence of
stomata do not do so in an unqualified manner.

In general, stomata may be designated as small gaps or open-
ings in the intercellular substance of serous membranes. Some
investigators assert that these openings are pre — others that they
are post — embryonic formations ; while still others maintain
that they are accidental.

One obstacle in the way of some definite conclusion is the fact
that investigations have been made on different animals, or at
least different parts of the same animal, under different condi-
tions, by different methods, and with conflicting results. An-
other obstacle is that some investigations have been carried on
to prove a preconceived idea and authors have read into every

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 239

point evidence in support of their idea without viewing the sub-
ject in an impartial manner.

The frog seems to have been especially studied, although the
toad, rabbit and Guinea-pig have frequently been used. The
membranes which have been most studied and where stomata
have been most frequently described are the diaphragm of the
rabbit and the mesentery of the frog. In a few instances the
cat, mouse, dog, and in one case man, has been made the subject
of investigation. The central tendon of the diaphragm has also
been an object of special study, but the investigators fail to
agree; the same may be said of studies of other serous mem-
branes. Yet in spite of these facts we are told "that stomata
are found with certainty in the serous membranes of all small
animals" (Krause).

The methods of investigation may be classified as follows, viz.,
1, absorption ; 2, injection ; 3, impregnation.

Absorption. This method depends upon the penetration of
solutions into the superficial lymphatics and was formerly much
used. Milk, blood, etc., were placed in contact with the cen-
tral tendon of the diaphragm and after a little most of the fluid
would be absorbed. Colored fluids, such as a solution of Berlin
blue, or fluids holding fine granules in suspension, as carmine or
Chinese ink, have been used. They were either introduced into
the body cavity or merely brought in contact with the diaphragm
by allowing them to drop on its peritoneal surface. Artificial
respiration has also been used to promote absorption ; it being
claimed that it had a direct influence — acting as a pump (Lud-

wig).

Injection. This may be done either by the "puncture
method" or by inserting a fine canula directly into a lymph-
vessel. Dybkowsky (4) claimed that by injecting the lymphat-
ics it could be shown that the superficial lymphatics of the
intercostal pleura lead freely between the endothelium of the
surface by short vertical branches. Schweigger-Seidel and
Dogiel (21) conclude from an injection of the cy sterna lym-
phatica magna of the frog that the body cavity was in open com-

240 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

munication with the former by means of circular openings —
stomata. i

Impregnation. This consists in treating the serous mem-
branes with some stain, generally nitrate of silver, which will
bring out the cell boundaries. Most of the later investigations
have been carried on by this method and it is the one I have
used exclusively.

Facts obtained by the first two methods, and to some extent
by the last, have lead many authors to assert that the irregular
distributed figures found between endothelial cells are stomata.
That such figures occur can not be denied ; but are they neces-
sarily natural pre-formed openings ? Or, granting that stomata
are present in the frog, does it necessarily follow that they are
present in mammals, which present a higher and more complex
structure ?

Significance of Stomata. Here again, as on the whole ques-
tion of stomata, the greatest diversity of opinions exists. The
greater number of the investigators who have expressed any
opinion in this matter, regard stomata as free openings afford-
ing passage to the superficial lymphatics. Ludwig, Schweigger-
Seidel, Klein, Rawitz, and others, speak of the passage of leuco-
cytes through these openings, and Ellenberger (5) adds that they
are sometimes plugged up with lymph cells. After referring
to the work of Schweigger-Seidel and Ranvier, Ellenberger says :
"These (the gaps in the intercellular substance) lead directly
into the lymph-spaces."

Ranvier (17), however, did not hold this opinion, for he says :

"Most hisfologists consider the small inter-endothelial spots as pre-
existing stomata designed for the free passage of the lymph cells;
* * * but the irregular distribution of these spots and their absence
if, previous to the employment of silver nitrate, the almuminate cov-
ering the surface has been removed, argues against the presence of
pre-existing openings. The presence of these spots upon the omen-
tum which is already so largely perforated, and where the passage
of white corpuscles is perfectly unnecessary, adds a further argument
against the opinion of those who would call these structures stomata."

In his chapter on the structure of the capillaries Ranvier ex-
presses himself as strongly opposed to the presence of the

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 241

stomata and stigmata described by Arnold; and, after referring
to the experiments of Cohnlieim, says:

"The number of stomata seem consequently to depend on the num-
ber of blood corpuscles which have passed through the walls of the
vessel, and this observation suggests the thought, contrary to the con-
clusions of Arnold, that the stomata are not preformed but that they
are produced within the capillaries by the passage of corpuscles."

Although Arnold (1) accepts the existance of stomata, he does
not believe in their open communication with the lymphatic sys-
tem. Rawitz (18) assumes the passage of leucocytes, but does
not seem to be able to convince himself that there are free open-
ings ; he suggests that there are "at least soft places."

Tourneaux (23) believes the so-called stomata are artifacts,
and says that he did not succeed in verifying a connection be-
tween the body cavity and the lymph-spaces. His conclusions
were based upon experiments with starch and carmine granules,
neither of which, he asserts, will penetrate into the lymph-ves-
sels when introduced into the body cavity. He concludes by
saying that the lymph cavity can be filled and the body cavity
remain empty, or vice versa, without the passage of the starch or
carmine from the one to the other.

The conclusions of Tourneaux are of special interest because
they directly contradict the views given above ; for most of the
authors mentioned, base their opinions upon the statement that
when solutions holding starch or colored granules in suspension
are injected into the abdominal cavity, the granules will after
some hours be found in the superficial lymph-vessels.

Muscatello (15) maintains that the central tendon of the
diaphragm is the only place where stomata may be found, and
even here they are somewhat doubtful. From the standpoint of
absorption and diapedesis it is difficult, indeed, to see why
stomata should be necessary to absorption in one region of a
serous cavity and not in another. If leucocytes can pass through
the walls of the blood and lymph-vessels without the presence of
stomata, it does not seem a good argument to say that they are
necessary elsewhere ; besides if stomata are a sine qua non to ab-
sorption they certainly ought to be found in the intestine.

242 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

RESULTS.

The great difficulty in the preparation of all my material was
the danger of mechanical injury during the removal of the
specimens from the animals, during the staining, and even in
mounting. As large pieces as possible were used, some measur-
ing 20x30 mm. The difficulty in obtaining large specimens
was the presence of blood-vessels and fat; these prevented the
use of high powers by not allowing the cover-glass to lie close
to the specimen throughout its entire extent. By the exercise
of great care specimens of the above mentioned size could be
obtained which showed no discontinuities, each epithelial cell
being bounded by sharp, continuous lines.

The distribution of such openings or discontinuities as I was
able to demonstrate in the epithelium of the peritoneal cavity
of the cat was extremely irregular. Their size and shape was
substantially alike on the central tendon of the diaphragm, the
mesentery, omentum, suspensory ligament and the peritoneal
surface of the diaphragm.

"No specimens were obtained where the occurrence of these
discontinuities obeyed any general rule or law. For, while
specimen "A" from the suspensory ligament might have less
than specimen "A" from the mesentery, specimen "B" from the
former might have more than "B" from the latter. Their dis-
tribution was found to be an entirely arbitrary one with respect
to the different regions of the peritoneal cavity. When present
the greater majority of these figures were found at the junction
of inter-cellular lines, PI. 14, fig. 4. If, however, discontinui-
ties were present in very large numbers, they were also found in
individual lines as well as at their intersection.

All manner of variations as to size and shape were found.
While in some parts of a given specimen they were more or less
circular in shape and located at the junction of several intercel-
lular lines, in other parts of the same specimen they would be
arranged in chains of various sizes, but usually larger struc-
tures, which in some instances nearly equaled the adjacent cells
in size, PI. 14, fig. 6. In some specimens one or more nearly

MILLER — CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 243

circular openings were seen at the center of four or five radially
disposed cells, PL 15, figs. 7, 8, 9. At first they were thought
to be examples of openings plugged by lymph-corpuscles, as
mentioned by Ellenberger, but a careful study of such speci-
mens stained with nitrate of silver alone or in combination with
nuclear stains showed that such was not the case. In addition
to these forms still others, usually smaller than the above and
more uniform in size and shape, were. found. These instead of
resembling small openings had the appearance of dots ; they
were often located at the intersection of intercellular lines or
on the cells themselves, PL 14, fig. 5.

Closely allied to these, but less frequent in occurrence and of
much greater significance, were small circular figures situated
at the intersection of intercellular lines. The peculiarity of
these figures was that the cell boundaries were visible either
above or beneath them, and could, by careful focusing, be traced
to a point of intersection.* These undoubtedly represent cases
in which, owing to a slight injury, the albuminous material in
the cement substance exuded in insufficient quantity to entirely ,
obscure the underlying boundary lines; or, owing to the same
cause, the silver solution penetrated beneath the epithelial cells,
giving rise to a slight diffusion, PL 15, fig. 10.

All figures which resembled mere discontinuities or clefts
were usually quite distinct and were bounded by lines very simi-
lar to the intercellular lines themselves. The more symmetrical
figures were largely outnumbered by the irregular ones. This
irregularity was not only one of size and shape, but also of dis-
tribution.

Stretching of a membrane at the time of its removal had the
effect of producing discontinuities along the intercellular lines,
PL 15, fig. 11. Schwartz (20) and Muscatello (14) have shown
that the differences in form of endothelial cells are dependent
upon the degree of contraction or distention of the organs which
they line; or in other words, that the shape of the cells is de-

*The study of these figures is greatly facilitated by the use of Abbe's stereo-
scopic eye-piece made by Zeiss of Jena.

244 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

pendent upon the degree of expansion of the epithelial mem-
brane.

In the case of stretched membranes the tension has been in-
creased to a point where the cells have been torn asunder. The
cement substance, albuminous in character, has exuded and given
rise to dots or circular figures when exposed to the silver stain,
while larger ruptures appear as various-sized and shaped open-
ings between the cells.

Mechanical force, when applied to freshly mounted specimens
in Canada balsam, would often cause separation of the cells. To
show the effect of mechanical force specimens which showed,
when first mounted in balsam, no openings, were subjected to va-
rious degrees of pressure. A certain relation between the dis-
tribution and number of the resultant interruptions and the
force with which the cover-glasses were weighted was found to
exist. The greater the weight the more numerous the openings,
and if the pressure was applied to any particular part of a cover-
glass a change in the shape of the cells would follow. This was
manifested by a straightening of the intercellular lines and the
appearance of numerous openings between the cells which ra-
diated more or less from the center where the weight was ap-
plied.

When the epithelium was underlaid by adipose tissue, blood-
vessels or Pacinian corpuscles, or in other words, when the
epithelium was supported by an elastic pad, separation of the
cells did not take place.

CONCLUSIONS.

As the result of my investigations I am forced to conclude
that in the central tendon, suspensory ligament, omentum and
mesentery of the cat there are no pre-formed natural openings
commonly called stigmata and stomata.

It is true that I frequently obtained figures which corre-
sponded with the usual description of these structures ; but, ow-
ing to their great irregularity of distribution, their equally great
diversity in size and shape, together with their mechanical pro-
duction, I am led to regard them as accidental formations.

MILLER— CONTRIBUTIONS FROM ANATOMICAL LABORATORY. 245

Indeed, my investigations have convinced me that the pres-
ence of these figures is a purely accidental and arbitrary one,
due to imperfect (possibly unavoidably so) methods of prepara-
tion.

BIBLIOGRAPHY.

1. Arnold, J. : Ueber Parenchymkanale und deren Bezie-

hung zu dem Blut- und Lynipkgefasssystem. Med.

Centralblatt. 1874.
Ueber die Beziehung der Blut- und Lymphgefasse zu

den Saft-Kanalen. Virchow's Archiv. Bd. 62.
Ueber die Kittssubstanz der Endothelien. Virchow's

Archiv. Bd. 66.

2. Bizzozero, G. e Salvioli, G. : Studi sulla struttura e sui

linf atici delle sierose umane. Parte I. Archivis per
le scienze mediche. Vol. I.

3. Bohm, R. : Experimentelle Studien iiber die Dura mater

des Menschen und der Siiugethiere. Virchow's Ar-
chiv. Bd. 47.

4. Dybkowsky: Ueber Aufsaugung und Absonderung der

Pleurawand. Arbeiten aus der physiolog. Anstalt
zu Leipzig. 1866.

5. Ellenberger: Histologie der Hausthiere. 1887.

6. Eoa, P. : Ueber die Beziehung der Blut- und Lymphge-

fasse zum Saftkanalsystem. Virchow's Archiv. Bd.

65.

7. Klein, E. : Die serosen Haute. Strieker's Llandbuch der

Lehre von den Geweben. Leipzig. 1871.

8. Klein, E. : The Anatomy of the Lymphatic System. Lon-

don. 1875.

9. Klein E., and Noble Smith, E. : Atlas of Histology.

London. 1880.
10. Kolossow, A. : Ueber die Structur des Pluero-peritoneal-
und Gefassepithels. Archiv f . mik. Anat. Bd. 42.

246 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

11. Kolossow, A.: Ueber die Structur des Endothels der

Pleuroperitonealhohle, der Blut- unde Lymphgefasse.
Biolog. Centralblatt. Bd. 12.

12. Krause, C. E. Th. : Handbuch der Menschlichen Ana-

tomie. Hannover. 1876.

13. Ludwig und Schweigger-Seidel : Ueber das centrum

tendineum des Zwerchfelles. Arbeiten aus der phys-
iolog. Anstalt zu Leipzig. 1866.

14. Muscatello, G. : La signification physiologique de la

forme des Endotheliums. Anat. Anz. Bd. 10.

15. Muscatello, G. : Tiber des Ban unde das Aufsaugungs-

vermoaen des Peritonaum. Virchow's Archiv. Bd'.
142.

16. Quain: Elements of Anatomy. 10th Edition. London.

1896. E. A. Schafer, editor.

17. Ranvieb, L. : Luhrbuch der Histologic Uebersetzt von

Nicati und Wyss. Leipzig. 1888.

18. Bawitz, B. : Grundriss der Histologic Berlin. 1894.

19. v. Recklinghauser, F. : Lymphgefasse und ihre Bezie-

hung zuin Bindegewebe. Berlin. 1862.

20. Schwartz, W. : Grossen imd Formveranderungen einiger

Endothelien durch Dehnung. Anat. Anz. Bd. 8.

21. Schweigger-Seidel und Dogiel : Ueber die Peritoneal-

hohle bein Forschenundihren Zusammenhang mitdem
Lymphgefasssystem. Berichte der siichs. Gesells. d.
Wissenshaft. 1866.

22. Stohr, Ph. : Lehrbuch der Histologic Jena. 1896.

23. Tourneaux, Fr. : Recherclies sur l'epithelium des sereuses.

Jour, de l'anat. 1874.

24. Tourneaux, Fr., et Hermann, G. : Becberclies sur quel-

ques epitheliums plats dans la serie animalc Jour,
de l'anat. 1876.

Plate 14.

Description of Plate 14.
Peritoneal Epithelum of the Cat.

Fig. 1. Epithelium from the omentum.

Fig. 2. Epithelium from the suspensory ligament.

Eig. 3. Epithelium from the mesentery.

Fig. 4. Epithelium from the mesentery, showing that the loca-
tion of the majority of the discontinuities is at the
intersection of the intercellular lines. A few dots
are seen which, if situated on intercellular lines,
would be called stigmata.

Fig. 5. Epithelium from the suspensory ligament. Note the
small figures of regular outline; some situated on
the intercellular lines, others on the cells them-
selves. The only difference between them is their
situation; if they are to be called stigmata in one
situation, why not in the other %

Fig. 6. Epithelium from the mesentery. This preparation
shows the widely divergent character of the inter-
cellular discontinuities.

BULL. UNIV. WIS., SCI. SER.

VOL. 2, PL. 14.

Plate 15.

Description of Plate 15.

Peritoneal Epithelum of the Cat.

Tigs. 7, 8, and 9. Three preparations from the mesentery.
These figures are of great interest because they
show how easily one might mistake the opening in
the first for a stomata and in the last two figures it
would be possible to say that they were small cells
filling up the opening of the stomata. Their posi-
tion corresponds to that assigned to stomata by
Klein, i. e., "in the center of radially arranged, rel-
atively large endothelial cells."

Pig. 10. Prom the mesentery. Note especially the figure which
is shown more highly magnified at the left. As
viewed under a low power the point indicated ap-
pears as one of the so-called stigmata, but when
viewed under a higher amplification, especially if
an Abbe stereoscpic eye-piece is used, it is easily
seen that the dark spot is under the epithelial cells
and that the cell boundaries are intact.

Pig. 11. Prom the mesentery. This figure shows the same ap-
pearance as figure 6, and also illustrates the effect
of stretching.

Pigs. 1-10 from the Cat; fig. 11 from the Frog. All figures
were drawn under the camera lucida.

BULL. UNIV. WIS., SCI. SER.

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. -tl

Science: Series, Vol. 2, No. 4, Pp. 247-296, Plates 16-22

THE ANOMALOUS DISPERSION OF CYANIN

BY

CARL EDWARD MAGNUSSON, Ph. D.
Fellow in Physics

Published bi-monthly by authority of law with the approval of the Regent*

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
July, 1900

PRICE 30 CENTS

gxxlletin of tit*? mnivcv&xtxj of pH^ccmcm,

<&0mtnittee of ^Publication

CHARLES KENDALL ADAMS, President of the University
WILLIAM HERBERT HOBBS, Editor-in-Chief

EDITORS

William Herbert Hobbs, Science

Charles Forster Smith, Philology and Literature

Frederick Jackson Turner, Economics, Political Science, and History

Nelson Oliver Whitney, Engineering

BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 41

Science Series, Vol. 2, No. 4, Pp. 247-296, Plates 16-22

THE ANOMALOUS DISPERSION OF CYANIN

BY

' r. •» i '

T :AL

CARL EDWARD MAGNUSSON, Ph. D.
Fellow in Physics

Published bi-monthly by authority of law with the approval of the Regents

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
July, 1900

CONTENTS.

Part I. Historical Survey.

(a) Experimental. .

(b) Theoretical.

Part II. Experimental Work.
Introduction.

(a) The Visible Part of the Spectrum.

(b) Investigations in the Ultra Violet

(c) The Method of Crossed Prisms.

(d) The Interferometer Method. .
Conclusion.

PAGE

249

258

268
269
274
277
279
287

Bibliography..

288

THE ANOMALOUS DISPERSION OF CYANIN.

PAET I.

HISTORICAL SURVEY.

(a) Experimental. — It has long been a well known fact that
prisms having the same angle of refraction, but made of differ-
ent kinds of glass, yield spectra which are wholly unlike one
another in character. Not only is the refraction or the devia-
tion of the light produced by one prism different from that
which results when a prism of different material is employed,
but the amount of dispersion, or the angular extent of the spec-
trum, depends likewise upon the material of which the refracting
substance is composed. Moreover, to a very great extent, re-
fraction and dispersion are independent of each other, so that
media are frequently found having a high refractive index but
a small dispersive power, and conversely, other media exist
having small refractive power but possessing high dispersion.
The angular distance between any two given wave lengths in
the prismatic spectrum depends, therefore, not only upon the
refracting angle of the prism but upon the nature of the ma-
terial of which the prism is made, so that in general, prismatic
spectra are unlike one another both in angular extent and in
angular distance between corresponding wave lengths. This
variability in the character of prismatic spectra is known as the
irrationality of dispersion.

Until the year 1840 no exception had been found to the gen-
eral law that short waves are deviated more than longer ones,
that is to say, that the order of arrangement of colors in the
spectrum is always the same although the distances between any

249

250 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

two given wave lengths may vary considerably. At about this
time Fox Talbot, while working with the double oxalate of chro-
mium and potash, made the remarkable discovery that prismatic
crystals of this substance have the power of deviating the red
more than the blue. Nothing was published on the subject,
however, until nearly twenty years later, when Le Eoux1 an-
nounced the fact that by a hollow glass prism filled with iodine
vapors the red rays are bent more than the blue. Talbot2 at
once recalled his early experiments and published an account
of what he had done. Speaking of the arrangement of the col-
ors in the spectrum produced by the double oxalate of chromium
and potash, he says : "The colors were very anomalous, -and
after making many experiments I came to the conclusion that
they could only be explained by the supposition that the spec-
trum, after proceeding for a certain distance, stopped short and
returned upon itself."

M. Hurion3 made quantitative measurements upon iodine va-
pors and found the refractive index for the violet and red rays
at TOO0 C to be ^==1.019; ,1=1.0205.

The first real impulse for extensive work upon this phenom-
enon was given by Christiansen4 in 1870, when he discovered
anomalous dispersion in an alcoholic solution of fuchsin.
Christiansen noticed that in the transmitted beam the green
light was absent, that the red, orange, and yellow rays were re-
fracted in their usual order, but that the violet was deviated less
than the red, so that a dark band lay between it and the red.

Fig. 1.

The relative arrangement of the colors in this spectrum is
shown in figure 1, in which the approximate intensities of the

i Le Roux, Comp. Rend., LV., p. 126 (1862). Pogg. Ann. CXVIL, p. 659; Ann. de Chim.
et de Phys. (3) LXL, p. 285 (1861).
1 Talbot, Proc. Roy. Soc. Edin. 1870-1871.
» M. Hurion, Jour, de Phys. (1), VII., p. 181.
* Chrietianien, Pogg. Ann. CXLL, p. 479; CXLIIL, p. 250; CXLVL, p. 154.

MAGNUSSOX AXOMALOUS DISPERSION OF CTAXIX.

251

light are represented by the height of the respective ordinates.
The great dispersive power of fuchsin became at once apparent
on comparing lengths of the spectra produced by the dye and
by pure alcohol, that due to the latter being represented by the
dotted lines in the figure. For an IS per cent, solution of
fuchsin in alcohol, Christiansen obtained the following indices
of refraction:

Table I.

Fraunhofer Lines.

B.

C.

D.

E.

F.

G.

H.

18 per cent Fuchsin solution

Pure alcohol

1.450
1.3628

1.502

1.561
1.3654

1.3675

1.312

1.3696

1.258
1.3733

1.312
1 3761

He worked' with solutions of different concentrations and
showed that the refractive index increases with the density of
the solution, but that this increase is different for the various
wave lengths.

When Christiansen published his first results the subject was
taken up very energetically by Kundt,1 who repeated the work
on fuchsin and examined many of the aniline dyes and other
colored solutions, such as indigo, carmine, and potassium per-
manganate. Many of these substances show "surface color,"
that is, they have the power of reflecting certain colors more
than others. Kundt made extensive experiments to show the
interdependence of the two phenomena and came to the conclu-
sion that all substances which show "surface color" also give
anomalous spectra. Continuing his experiments he found that
a very close relation exists between dispersion and absorption,
and that anomalous dispersion depends upon the selective ab-
sorption of the medium and not upon the "surface color." This
discovery of the relation between absorption and dispersion has
been of the greatest importance and has enabled later investi-
gators to contribute much to our knowledge of dispersion.
Kundt embodied his conclusions in the following statement,
which is known as Kundt's Law,2 to which no exception has as

i Kundt, Pogg. Ann. CXLII., p. 163; CXLIII., pp. 149, 259; CXLIV., p. 128: CXLV.,
pp. 67, 164.
a Kundt, Pogg. Ann. CXLIII., p. 265.

252

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

yet been found: "Coming from the red end of the spectrum
and approaching an absorption band the refractive index is ab-
normally increased, and coming from the violet end towards the
absorption band the refractive index is abnormally decreased."
To make the peculiar variations in the refractive index di-
rectly visible to the eye, Kundt employed the method of crossed
prisms1 as first used by Xewton2 in ordinary dispersion. A
beam of white light is first dispersed by a glass prism placed
with its refracting edge vertical. This spectrum is then passed
through a hollow prism filled with an alcoholic solution of
cyanin and placed with its refracting edge horizontal. Thus
the prisms have their refracting edges at right angles to each
other so that the first one deviates the light in a horizontal plane
while the second bends the rays in a vertical direction. Sup-
pose the deviation is simply inversely proportional to the wave
length, that is, a normal spectrum, such as is produced by a
grating, in each case, the resulting crossed prism spectrum will
become a diagonal band having the violet end elevated. This
is seen in (a), Fig. 2. The lower band shows the appear-
ance of the spectrum produced by the first prism only, while

IflFTT

UinlR-rl

O).

ess:

Vital ni

W-

Z Fig. 2.

c/

a

£-n_

E5S3

(*;.

the diagonal band represents the final result after passing
through both prisms. If now the dispersion of the second
prism was irrational, as is the case with ordinary glass, the final
result would be a curved band as is seen in the upper part of
(b), Fig. 2. If the common glass prism is removed and a
hollow prism filled with a cyanin solution, as used by Kundt,

I Kundt, Pogg. Ann. CXLIV., p. 133.
a Newton's Opticks, Book I, Prop. II.

MAQNUS80N — ANOMALOUS DISPERSION OF CYANIN. 253

is placed in the second position, the crossed prism spectrum will
be broken into two bands as is seen in (c), Fig. 2. The red is
deviated very much and the band turns up sharply as the orange
is approached ; the yellow is absorbed, and hence, absent, leav-
ing the spectrum in two parts ; the green is bent least, while the
deviation rapidly increases as the violet is approached. This
method is very striking to the eye and gives an easy means of
determining roughly the nature of a spectrum.

With the dye in solution and placed in a common hollow
prism, the deviation produced by the solvent is superimposed
upon that made by the dye itself. To separate the two, Soret1
made a glass trough with parallel sides, having a diagonal glass
partition. On one side he poured the solution and on the other
the pure solvent. Consequently, any deviation in the light was
due to the dissolved substance onlv and not to the solvent. Still,
it must be noted that a substance when dissolved may not have
the same optional properties as when in the solid state. For
the same purpose DeKlercker2 used two hollow prisms of the
same angle and placed in opposite directions, the one being Slled
with the solution and the other with the solvent.

Quantitative measurements, by the ordinary spectron ieter
method, for determining the refractive index for various v:ave
lengths have been carried out by several physicists. Sie;>en3
and Ketteler4 in particular made a large number of observations
upon various substances, in several solvents, and at different
temperatures and concentrations. Among the solvents used
were alcohol, chloroform, and water. Their aim was to make
experimental observations upon which they could base a theory
that would explain this strange phenomenon. This experi-
mental data was afterwards used bv Ketteler in his theoretical
deductions and some important results were reached. Still, it
cannot be said that he succeeded in establishing the theory ad-
vanced, inasmuch as it is evident that a substance in solution

i Soret, Pogg. Ann. CXLIIL, p. 325, (1871).

* DeKlercker, Comp. Rend. LXXXIX. (1879).

8 Sieben, Wied. Ann. VIII., p. 137 ; XXIII., p. 312.

* Ketteler, ibid. XII., pp. 363, 481.

254

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

may have entirely different optical properties from those which
it possesses in a solid state.

To avoid this objection several indirect methods based upon
the properties of the solid dye were devised. The results ob-
tained do not warrant a detailed description, but a bare state-
ment of the methods used will be made. Sieben employs a
method based on the total reflection of light from the surface of
the solid dye. By measuring the absorption of the solid dye for
various wave lengths, Wernicke1 was able to calculate the index
of refraction, and for fuchsin his results are given in Table II.

Table II.

A

581

571

532

483

466

488

438

M

2.326

2.372

1.875

1.530

1.288

1.224

1.295

"Wiedemann,2 Lundquist,3 and Merkel4 made observations to
dete mine the elliptic polarization of the light reflected from the
surface of the solid substance. The work of these and several
othe r observers, although of great interest, is so dependent upon
a m. ruber of doubtful assumptions that to show the real value of
the results a detailed description must be made. The latter is
out-side the limit of a brief outline and must be omitted. Al-
thc'igh the refractive index, and therefore, also, the velocity of
the light in the substance can be calculated by these indirect
methods, still, the direct observation of refraction by a solid
prism is by far the simplest and surest procedure. As early as
1875 Wernicke5 determined the indices given in Table III., by
means of a prism of solid fuchsin.

Table III.

Fraunhofer lines.

A.

B.

C.

G.

H.

M

1.73]

1.81

1.90

1.31

1.54

i Wernicke, Pogg. Ann. CLV., p. 87.

9 Wiedemann, ibid. CLI., p. 1, C1874).

* Lundquist, ibid. CLIL, pp. 177, 398, 565, (1874).

« Merkel, Nov. Act. Koy. Soc. Upsala, Ser. III.

» Wernicke, Pogg. Ann. CLV., p. 93, (1875).

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN.

255

It appears that only one prism was made and that was far
from being satisfactory, for in speaking of the results Wernicke
says that the A and B lines were "plain," the rest "uncertain."
The D, E, and F lines could not be determined as the prism ab-
sorbed all the light in this part of the spectrum.

It was almost twenty years later that Pfliiger1 succeeded in
making solid prisms of several of the aniline dyes. The method
of making the prisms is as follows : A piece of glass tubing is
laid upon a piece of plate glass, and in the prismatic opening
between the two an alcoholic solution of the dye is placed, drop
by drop, and allowed to evaporate. The solid dye will thus fill
up the prismatic space between the tube and the plate. When
the deposit is of the desired thickness, the process is stopped,
the glass tube removed by a sharp blow, and a small bi-prism is
thus left on the glass plate. This is simple in theory but tedious
in practice. To secure three good prisms Pfliiger2 made over
three hundred attempts, and still even the best had optically
poor surfaces. Since the angles of the prisms used by Pfliiger
were very small, the largest being 2' 9". 6, the irregularities in
the surface became serious sources of error, inasmuch as a small
error in measuring the angle of the prism produces a large per-
centage error in the results. With solid prisms of several of
the aniline dyes, formed in this manner, Pfliiger determined
the refractive indices, for the visible part of the spectrum, by
the usual direct spectrometer method.

Fuchsin and cyanin received the most attention and the aver-
age results obtained by four prisms of the latter are given in
Table IV.3

Table IV.

A

700

671

656

645

620

589

565

540

535

520

505

486

M

2.05

2.13

2.19

2.23

1.94

1.71

1.39

1.25

1.20

1.19

1.28

1.40

With cyanin he extended his experiments into the ultra vio-
let. To do this he used an iron arc spectrum, dispersed by a

i Pfliiger, Wied. Ann. LVI., p. 412, (1895) ; LXV., pp. 173, 214, 225, (1898).
a Pfliiger, ibid. LXV., p. 205, (1898).
s Pfliiger, ibid., p. 206.

25C

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Rowland's concave grating. Between the grating and its focus-
he placed the small cyanin biprism with its refracting edge par-
allel to the lines of the grating. The double set of bright lines
thus formed at the focus were photographed. The distance be-
tween the corresponding lines in the two sets were measured and
from these measurements the refractive indices were calculated.
These results are given in the following table :

Table V.

Prism.

a

438

407

405

378

350

288

1

0

83"
126/4

1.59

1.68

1.70

1.69

1.70

1.71

Mea

nM

1.59

1.68

1.70

1.69

1.70

1.71

The objective point of Pfliiger's work was to test the Ket-
teler-Helmholtz dispersion formula, the derivation and form of
which will be given in the theoretical part of this paper. The
equations require experimental data for both the extinction and
refraction indices. To find the former, Pfluger employed a
Konig's spectro-photometer, by which the absorption of the light,
when passing through a thin film of cyanin, was measured.
The ratio between the original intensity, I, and the strength af-
ter passing through the film I', is found by equation (1), where
a is given by the reading of the photometer.

I' — Cot a

(D*

The extinction index, X, is then calculated by the usual form-
ula-, (2) , where d is the thickness of the film, X the wave length
of the light in free space, and e the base of the natural system of

logarithms.

I 4ffXd

T = e-

A

(2).

In the series of papers published by Pfluger are found several
tables for the extinction index. The disagreement between the
calculated and observed values led him to repeat this work with

MAGNUSSON — ANOMALOUS DISPERSION OP CYANIN.

257

special care and the results for solid cyanin films given in his
last1 paper are shown in Table VI.

Table VI.

A

635

620

589

570

565

535

520

505

486

440

400

u

0.53

0.67

0.69

0.75

0.74

0.46

0.26

0.15

0.06

0.00

0.00

Pfliiger made an elaborate comparison of these data with the
values calculated by the Ketteler-Helmholtz dispersion formula.

To overcome the difficulties of making prisms by Pfliiger's
method and in hopes of securing better results R. W. Wood2 dis-
solved the dye in Canada balsam and poured the solution while
hot into the V shaped opening between two glass plates. Al-
though the prisms thus made were superior to those obtained by
Pfliiger, the dye was still in solution and the same objection
could be made as for dyes in alcoholic solution. He next tried
to fuse several of the aniline dyes and found that with cyanin
this was a singular success. While in a fluid state the cyanin
was pressed into an acute prism between two pieces of plate
glass. After cooling, one of the plates was removed by a sharp
blow, the prism remaining fixed on the other. The advantages
of this method are several :

1st, The rapidity and comparative ease of making good prisms.

2nd. The increased accuracy of the measurement of the re-
fracting angle which the superiority of the optical surface
makes possible.

3rd. The improved definition of the transmitted beam on ac-
count of the uniformity of the prism.

4th. The ability to obtain prisms of almost any desired angle.
Pfliiger considers an angle of 2' 6."4 remarkably large
while by this method prisms have been made with a re-
fracting angle of 2° and over and no special difficulty
would be met if larger angles were desired.

1 Pfliiger, Wied. Ann. LXV., p. 227.

s Wood, Phil. Mag. XLVL, p. 380, (1898).

258 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

(b) Theoretical. — The great importance of the phenomenon
of anomalous dispersion in the theory of light is, perhaps, best
seen when the various theories framed for the explanation of
dispersion are examined. Kundt's discovery of the evident de-
pendence of dispersion upon absorption rendered necessary a
thorough revision of the older theories regarding this phenome-
non.

The fundamental assumption of the wave theory of light is
the existence of a medium, called the ether, which pervades all
space and in which luminiferous vibrations are propagated as if
in an elastic solid. Upon this basis the velocity of transmis-
sion* of a light wave is given by the expression,

V = cl/§ (3).

i

where E is the elasticity of the medium; D, its density; V,
wave velocity ; and C, a constant.

To account for the difference in the velocitv of the transmis-
sion of light in transparent media and in free space by this equa-
tion, three suppositions may be made.

(a). E may be constant and D variable, .\ V = -g- (4).

(b). E may be variable and D constant, .*. V = C2 V~E, (5).

(c). Both E and D may vary, .-. V = C V g (6).

The first assumption was made by Fresnel1 while the theories
of Neumann2 and llcCullagh3 depend upon the second. Both
assumptions lead to identical results, except, that the plane of
vibration must be considered perpendicular to the plane of in-
cidence in the first case and parallel to it in the second. The
third case, if treated by methods similar to those employed by
Fresnel, Neumann, or McCullagh, leads to results not agreeing
with known facts. These theories would be sufficient to explain

I Fresnel, Ann. de Chim. et de Phys. XLVI., p. 2IJ5. Oeuvres complete, I., p. 767,
3 Neumann, " Vorlesungen ilber Tkeoretische Optik," edited by Dr. E. Dorn, Leipzig,
1885.
3 McCullagh, Trans. Roy. Soc. Irish Acad. Vol. XXL

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN. 259

refraction if all colors were deviated the same amount, but for
dispersion, or the difference in the velocity of transmission of
light of various wave lengths they offer no solution.

To explain the fact that in material media light waves, dif-
fering in wave length, are propagated with different velocities,
while in free space all light waves are transmitted with the
same velocity, Cauchy1 made the following assumptions :

1st. That the ether is of a granular structure.

2nd. That there is a certain attractive force between ether and

matter so that inside a material body the ether is very much

denser than in free space.
3rd. That the distance between the ether particles inside the

body is comparable to the wave length of light, while in free

space it is of a different order.
4th. That the period of vibration of a wave is constant, and

hence, that the wave length varies with the velocity of

transmission.

From these assumptions Cauchy developed the following ex-
pression for the velocity of transmission of light in terms of the
wave length in the medium :

*&'

V» = A, + A2 (?£)"+ A3 (2£)4 + &ct. (7).

where A1} A2, A3, etc., are constants depending upon the nature
of the medium. While calculating the values of these con-
stants he observed that this series is rapidly converging and that
for all practical purposes it may be sufficient to use the first two
terms, thus:

(¥)' . (8)'

V'^A. + A,

From his 4th assumption there results : a : a' : : v : / where A is
the wave length in free space and v the velocity. Combining
this with equation (8), making a series of transformations, and

1 Canchy, Memoire sur la dispersion de la lumiere. Prag. 1836. Beer:— Einleitung in
der hoheren Optik, p. 209, Braunschweig, 1853.

260 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

dropping terms of higher order, he derived the following equa-
tion for the index of refraction :

/7¥ = A1 + -_r + 1r+&ct. (9)>

ChristofTel1 showed that when Cauchy made his transforma-
tions to derive (9) from (8) he assumed A2 to be small in com-
parison with Ax and, hence, practically used only one constant.
ChristofTel devised a new method of solving equation (8) that
did not require the second assumption, and showed that the in-
dex of refraction can he represented by equation (10) :

po V7

V -i -4- h + V 1 — h (10).

1 1

The problem of dispersion was also studied by Redtenbecker2
and upon the supposition that each molecule is surrounded by a
dense ether shell he obtained the formula :

1

M

-2= A + Xi + C A3 (ii).

The subject was next treated by Briot.3 He considered the
assumptions made by Cauchy insufficient to explain dispersion,
inasmuch as a change in density alone could not give a different
order to the distances between the ether particles, and conse-
quently, if the wave length were a function of the velocity in-
side a material body the same must be true in free space. To
remedy this defect he assumed a direct action of the material
particles upon the velocity of the transmission of light and ex-
pressed this by adding a term KA.2 to Cauchy's formula, thus:

j2 = K ,\» + A, + ~i + 4r + Act. jig).

This formula he tested by the best experimental data obtainable
and found that the term KA2 was small and in most cases could'

) Christoffel, Pogg. Ann. CXVIL, p. 27, (1861).

2 Redtenbecker, Dynamiden-System. Mannheim, (1857>.

3 Briot, " Essai sur la theorie mathematique de la lumiere." Paris, 1863; Leipzig,.
1867: C. R. LVIL, p. 866.

MAGNU8S0N — ANOMALOUS DISPERSION OF CYANIN. 261

be neglected. Ketteler1 in 1870 determined the value of the
constants, in Briot's formula, for several substances and found
that the calculated values for the index of refraction agreed
closely with those observed.

It was at this time that Christiansen and Kundt brought the
phenomenon of anomalous dispersion into prominence. These
remarkable observations could not be explained by either
Cauchy's or Briot's equations, but rendered necessary the con-
struction of a new theory.

Sellmeier2 made the first attempt and laid the basis for fur-
ther work. His assumptions are as follows :

1st. The existence of an ether of constant elasticity and density.

2nd. The retardation of the light is entirely due to the inter-
action between the ether and the material particles.

3rd. The intensity of the interaction depends upon the ratio be-
tween the natural period of vibration of the material parti-
cles and of the wave length, and that an absorption line re-
sults when this ratio is unity.

4th. That each material particle is entirely free to vibrate with-
out affecting the other particles.
Several minor assumptions are made in the development of

the first equation to simplify the calculations or even to make

them possible.

From these assumptions Sellmeier deduces the following

formula for the refractive index :

m ta ag

. ! ?*> -d' (13).

m' a"

Where t equals period of vibration of *■.

Where d equals natural period of- vibration of material particle.
Where a0 equals amplitude of center of gravity of material par-
ticle.
Where a equals amplitude of ether vibration.
Where m' equals mass of ether in unit volume.
Where m equals mass of matter in unit volume.

i Ketteler, Pogg. Ann. CXL., p. 1.

a Sellmeier, Pogg. Ann. CXLV, pp. 399, 520 ; CXL VII., pp. 387, 535, (1873).

262 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

It is noteworthy that Lord Kelvin1 in a paper read' before the
Koyal Society of Edinburgh, February 6th, 1899, on the ab-
sorption line of sodium vapors, used Sellmeier's formula.

Kelvin's2 theory is quite similar to that of Sellmeier, the
chief peculiarity being the conception of concentric spherical
shells, connected by zigzag springs, to represent a molecule hav-
ing more than one natural period of vibration.

Under the assumption of a diatomic molecule of this form he
writes the equation thus :

/V2\2 m T8 m, T»

YV\/ = X + T2 — K2 + Ts — K^ (14>-

Where T equals period of vibration of ether light wave.
Where K equals natural period of vibration of one shell.
Where Kx equals natural period of vibration of the other shell.
Where m equals density of 1st shell, using ether as unity.
Where mj equals density of 2nd shell, using ether as unity.

This theory of mutual reaction between matter and ether was
next developed by Helmholtz.3 Let u, v, w, be the displace-
ments of the ether particles of density m, in an element of
volume dv; U, V, W, the displacements of the material parti-
cles of density m'; then, considering the forces along X axis
only, he forms two equations of motion, thus :

u

m

m

dt8

dHJ
dt8

= X+X' + A+&ct. (15a).

= Xx + X', + A, + Act. (isb).

Where X equals action of ether particles external to dv ;

Where X' equals external impressed force on m.

Where A equals direct action of the material particle in dv on

the ether ;
Where Xx equals action of matter external to element dv.
Where X'x equals external impressed force on m.
Where Ax equals direct action of the ether in dv on the material

particles. ___^

i Kelvin, Phil. Mag. XLVII., p. 302.
2 Kelvin, Baltimore Lectures, 1884.
■ Helmholtz, Pogg. Ann. CLIV., p. 582.

MAGNUSSON — ANOMALOUS DISPERSION OP CTANIN. 263

To derive expressions for these forces, Helmholtz made the
following assumptions :

1st. The impressed forces are supposed to vanish; hence:

X1=X1' = 0.

2nd. The medium is supposed to be perfectly elastic ; hence :

d2u
x = a2 d^~ <17a)-

dU
X1=-a*U-r2-df (17b).

3rd. The force of restitution in an elastic medium is propor-
tional to the displacement ; hence :

A = /?» (U — u) (18).

4th. The action is supposed to be confined to the element of
volume dv; hence:

A + A1=0 (19.)

Substituting the values thus found for X, X„ X', X'l5 A and
Aj in (15a) and (lob) we have :

d2u d*u

m ~dt»~ = a* dz»~ + £" lU — u) (20b).

d8U dU

m' dF" = ~ /Sa (U ~ u) ~ a* U ~~ r* dF (2°b)«

These are the fundamental differential equations in Helm-
holtz's dispersion theory. Solving, he finds:

B

^_ [7i-A)2i_i]

.4m L^ m' / A2m J

, v, ., BA2 mm' X*m
U ■ ~~ X ~ 1 - Jnh»; + 77 B \ A* TV . „ A» (21a).

- [O-^^-^' + o-

A*

B« G A*

m m' Asm
2 Mo X0 = p ^1 TF (21b).

Where ^ equals the refractive index at perpendicular inci-
dence ; x0, the extinction coefficient, for X at perpendicular in-
cidence ; and Am) wave length of absorption band.

264 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Lommel1 makes the same arguments as Helmlioltz except for
the force A, but considers the "action to follow Newton's law of
friction," and, hence, his fundamental equations become :

d2u d2u d „

md^ = a2 d^"T/*a dt(IJ-u) (22a).

daU d dU

m' dF= ± ^dt (U~u) ~aJ U-r2 df (22b),

Lommel gave the first set of signs but Ketteler2 and Voigt3
argued that the lower set should be used. Lommel4 replied,
still defending his first position, but, in the opinion of Glaze-
brook,5 without success.

Solving equations (22) and (23)

Ba _AT/ _A*_ \

mm' A»m\A»m_1/

M2o~ X2o — 1= /—* \1 7~B' \s A2 (23a).

(A.3 V / B' V A.2

B'3 /B2

„ v B' A3 mm' \m' / m

Ketteler6 makes a third suggestion. He supposes the action be-
tween ether and matter to be proportional to the acceleration in-
stead of the velocity as suggested by Lommel, therefore, ex-
pressing the force A thus :

<52
A = ^(U-u) (24).

The resulting equations when solved can be reduced to those of
Helmholtz by making Ba2 == B". Ketteler7 has written a large

1 Lommel, Wied. Ann. III., p. 339.
3 Ketteler, ibid. XVIII., p. 387.
» Voigt, ibid. XVII., p. 468.

* Lommel, ibid. XIX., p. 908.

5 Glazebrook, B. A. A. S Report, 1885. p. 222.

• Ketteler, Theoretische Optik, p. 78.

7 Ketteler, Wied. Ann. XVI., p. 86; XII., p. 383; XV., p. 613; XVIII., pp, 337, 631; XXI.,
pp. 199, 178; XLIX., pp. 382, 509; LIII., p. 823.

MAGNUSSON — ANOMALOUS DISPERSION OF CTANIN. 265

number of papers, in which dispersion is discussed from several
points of view. To briefly state his views would be impossible,
still, the main idea in his works on dispersion seems to be this :
the mutual reactions between ether and matter, that is, the A'
and A forces, are unknown, and, hence, they should be elimi-
nated from equations. The total work done per unit of time
on the whole system is equated to the rate of change of kinetic
energy, and in this the mutual reactions do not appear.1 Thus,
he obtains the f ollowing equation :

m

d2u d2U

^T du + m' -^r dU = e V2 u du - K U d U. (25).

Where u, U are displacements and e the rigidity of ether in free
space. The notation is changed so as to make it uniform
throughout this paper. Those equations he combines with a
"second equation relating to the special mode of action of the
matter particles which can be no other than the renowned funda-
mental equation of Bessel's theory of the pendulum." This2 he
writes :

d2u d2U

m dt2" c + m' dt2" = — K u- (26).

These equations would apply for transparent media, and when
absorption takes place terms are added for the reaction of the
matter on the ether. The fundamental equations then become3

d£u d*U d2u dU

mdt2"-m'dFC==ed^" + bm'U + cm'"dT (27a).

d*u d8u dU

■dFC+ dt2~ = -K'U-g'-dt (27b).

i Ketteler, Wied. Ann., XXI., p 201.

a Ketteler, ibid. XXI., p. 201 ; XVIII., p. 413.

* Ketteler, " Theoretische Optik," pp. 93-95.

2

266 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Solving these, Ketteler finds :l

V A*m / Am Am V A*m /

(a^-1) + g av (28a>-

/V-X02-1 = C r

m

2Mo X0 = C r

V A2m ' Am Am V A-m /

m /A8 \2 „ A3

(l^-1) + G° A^ (28b).

A new phase was given to the subject in 1893 when Helm-
holtz2 produced his theory of dispersion based upon the electro-
magnetic theory of light. He postulates charged bodies im-
bedded in an ether transmitting electric disturbances, and that
the forces acting upon the ether during these disturbances can
set the material particles in vibration. He follows the electro-
lytic theory in assuming that electric charges of definite magni-
tude are accumulated at the center of affinity of chemically com-
bined ions, that these charges may be either positive or negative
but always have the same absolute value for every center of
affinity. "If the ether surrounding a pair of combined ions is
traversed by electric forces and thereby dielectrically polarized,
the oppositely charged ions will be subjected to stresses in the
direction of the lines of force, that is, to two forces of equal mag-
nitude but opposite in direction which together form a couple ;
this couple will not set the center of mass of the molecule in
motion, but it will tend to lengthen or. shorten the electrical axis
of the molecule and to deflect it towards or away from the direc-
tion of the lines of force." The pairs of ions as used by Helm-
holtz possess mass and inertia in addition to the usual properties
of dielectrically polarized molecules of insulating substances.
Hence, oscillations may throw them out of equilibrium and pro-
duce variations in the electrical moments due to these ionic
charges, f, g, h, forces, independently of the electrical moments
per unit volume, f, g, h, forces, of the free ether.

i Ketteler, " Theoretische Optik," p. 100.

» Helmholtz, Wied. Ann. XLVIII., pp. 389, 723; L. E. XXXVII., p. 404.

MAGNUS80N — AN0MAL0U8 DISPERSION OF CYANIN. 267

In the energy equation Helmholtz takes account of electro-
static, magnetic, electro-magnetic, and mechanical forces and de-
rives equations representing each. Finally, he applies the Prin-
ciple of Least Action considering variations to be present in
f, g, h„ f, g, li, and f, g., h, and derives an expression for the re-
fractive index.

Heaviside1 criticizes several points, especially the term elec-
tro-magnetic energy, and the application of the Principle of
Least Action.

Ketteler2 has shown that the dispersion formula developed by
Helmholtz, from the electro-magnetic theory, and the one pub-
lished by himself, based on the elastic solid theory, can be ex-
pressed by the same equation.

, y, ^ ^ DA» a' -*.'„)
Mo - * - 1 =-2 (A3_A2m)a + g2 A2 (29a).

D g A3

2Mo X0 = 2 (As_A3m)2 +g2A3 (29b).

Where /*0 equals refractive index for wave length A. at perpen-
dicular incidence.

Where X0 equals extinction index for wave length at perpen-
dicular incidence.

Where A^ equals wave length in free ether of rays absorbed.

Where D equals a constant depending, in the elestic theory, upon
the refractive index of infinitely long waves, and, in the
electro-magnetic theory, upon the dielectric constant of the
medium. These equations are usually termed the Ket-
teler-Helmholtz dispersion formula, and were tested by
Pfliiger3 as described in the first part of this paper.

i Heaviside, L. E. Vol. XXXVII., p. 470.

a Ketteler, Wied. Ann. XL1X., p. 382 ; LIII., p. 823.

a PflUger.Ibid., LXV., pp. 173, 225.

268 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

PAET II.

EXPERIMENTAL WORK.

The superiority of the optical surface of cyanin prisms, made
by pressing together the fused crystals between glass plates, and
the larger angles available lead one to suppose that more ac-
curate determinations of the dispersion can be made with such
prisms than with those obtained by the evaporation of alcoholic
solutions of the dye. Of special theoretical interest are the
values of the refractive indices for wave lengths within the ab-
sorption band. The results of the experiments give conclusive
evidence of the continuity of the dispersion curve, through the
absorption band in the yellow and show the presence of a second
absorption band in the ultra violet, beginning at wave length,.
368 fi fi, which has not been heretofore observed and which
should be taken into account in proving the Ketteler-Helmholtz
dispersion formula.

The first part of the experimental work consisted of a syste-
matic examination of all the available aniline dyes known to
show anomalous dispersion with a view to determining :

1st. How many of them could be formed into prisms by the
fusion method.

2nd. The precautions necessary for the formation of prisms
of the best quality.

From Fuchsin, Aniline Green, Hoffmann's Violet, Uranin,
and Aurine, prisms were made, but with difficulty. Their qual-
ity was, however, too poor to warrant any further work. The
Uranin absorbs moisture from the atmosphere and dissolves if
not protected. Acid Magenta, Erithrosene, Aniline Red, Rose
Bengale, Genetian Violet, and Methyl Blue could not be made
into prisms by this method. Gyanin fuses at about 116 °C, be-
coming a pasty substance for a few degrees and then a liquid of

MAGNUSSON — ANOMALOUS DISPERSION OP CYANIN. 269

a deep plum color and of the consistency of a rather thick syrup.
The crystals when heated to about 80° C change color from a
bright green to a golden brown. After fusing the cyanin
rapidly evaporates and leaves a solid residue.

To secure good prisms the heating of the cyanin must be done
rapidly, the prism formed, pressed, and cooled quicxly and at
the right temperature. If too cool, the fused mass can not be
pressed into the required thinness ; and if too hot, a number of
small pin holes will appear, due to the gas bubbles formed. The
pressure applied is also a factor tjiat must be carefully adjusted
if good results are to follow. This becomes very important
when thin prisms are desired. For work in the transparent
parts of the spectrum, prisms of 10' to 20' angle can be used,
but in and near the absorption band they must be exceedingly
thin to let any light through.

Cyanin being found to be the only dye from which wholly
satisfactory prisms could be formed it was decided to limit the
work to an examination of the dispersion of this single sub-
stance.

Four distinct methods have been employed, namely :

(a) Direct spectrometer readings in the visible spectrum,
the slit of the instrument being illuminated with monochro-
matic light.

(b) Photographic records of the deviation of a system of
monochromatic rays from a Rowland concave grating illumin-
nated by an iron arc.

(c) A qualitative method based on Newton's principle of
crossed prisms.

(d) Photographic records of the displacement of the fringes
in the Michelson interferometer produced by thin films of
cyanin.

(a) The visible part of the spectrum. The first method was
employed by Wood:1 A plan of the apparatus is shown in
figure 3. Sunlight reflected from a heliostat (A) is concen-

*Phil. Mag. XLVI (1898), p. 380.

270

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

trated upon the slit of a large, direct vision spectroscope (C),.
the eye-piece of the latter being removed, and in its place is
fixed the slit of a Geneva Society Spectrometer (D), the eye-

*-C

Fig. 3.

piece of which is provided with a filar micrometer. The glass-
plate on which the cyanin prism (E) had been formed was cov-
ered with black paper, in which two small apertures had been
cut, one coming over the cyanin prism and the other slightly to
one side of it. The latter, or clear aperture, gave a direct image
of the slit of the spectrometer ; the former, a deviated image, due
to the bending of the rays by the prism. Both images being in
the field of the telescope at once, the distance between them could
be measured by the filar micrometer, and these readings when
reduced to the circular scale, furnished the data from which the
refractive indices were calculated. Any slight deviation due to-
the possible prismatic form of the glass plate used was thus elim-
inated. By turning a tangent screw, operating on the prism
system of the direct vision spectroscope, the focused spectrum
could be made to traverse the slit of the spectrometer, which was
thereby illuminated with monochromatic light of any desired
wave length.

To determine the wave length of the light corresponding to
any particular reading of the cyanin prism the following meth-
ods were used. First, by opening the slit rather wide a consid-
erable portion of the solar spectrum was allowed to enter the-
instrument in which the Fraunhofer lines were distinctly visi-

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN. 271

ble. Some line of known wave length was chosen and by nar-
rowing the slit the spectrum was gradually cut down until only
light in the immediate vicinity of the line remained. In those
parts of the spectrum where no conspicuous and easily recog-
nized line existed a different method was employed. Remov-
ing the prism and placing a small mirror in its place, the light
was thrown on a Brashear reflection grating spectrometer (See
H, Fig. 3). This instrument had previously been graduated
and the readings for the principal Fraunhofer lines been taken
in its fixed position, and, hence, the wave length of any light
used could be determined.

The angles of the cyanin prisms were measured by the Geneva
Society Spectrometer. The prism was placed with its refract-
ing edge vertical and at the center of the circular table. Par-
allel rays (a b, Fig. 4) coming from the collimator are reflected
from the glass plate in the direction b d and from the surface of

Fig. 4.

the prism along b c. The angle e between the reflected rays is
twice the angle of the prism. For prisms of small angle both
images of the slit were in the field of the telescope and the dis-
tance between them was measured by a filar micrometer. These
readings were then reduced to the circular scale. For larger
angles the readings were taken on the circular scale direct.

If A represents the angle of the prism and d the deviation,
both in circular measure, the index of refraction is found by
the usual formula:

sin Yo, (A + d)
M = ainy2 A (30).

272 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

The angles of the prisms being very small, we can replace the
sides of the angles by their circular measures, thus : —

^ = 1+A (3D.

By this formula the indices given in Table VII were calculated.

Plate 16 shows graphically the contents of Table VII. The
abscissae are wave lengths in /x /x units, while the ordinates are
indices of refraction.

For three reasons the results are not so good in the absorption
band as in the red and blue parts of the spectrum. These are :

1st. To transmit the yellow light the prisms must be very
thin, and hence, of small angle. This increases the percentage
error in measuring the angle of the prism as well as the devia-
tion.

2d. The image of the slit made by the deviated ray was not
as sharply denned in the absorption band as in the transparent
parts, a diffraction haze appearing around the image due to the
narrow portion of the prism through which the light could pass.

3d. Any slight error in measuring the wave lengths would
affect the result to a larger degree in this portion of the curve
than in the other parts.

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN.

273

Table VII.
Prism No. 1. Angle 17' 3" .8.

A

M

A

M

A

M

A

M

765.0

1.920

479.8

1.387

463.7

1.434

434.2

1.524

| 759.0

1.970

479.2

1.387

461.0

1.449

429.5

1.535 ;

735.0

1.985

475.6

1.416

456.8

1.460

427.0

1.533

703.5

2.050

475.3

1.401

451.8

1.479

419.1

1.544

688.7

2.131

472.7

1.408

444.2

1.496

410.8

1.537

685.6

2.150

470.0

1.418

438.0

1.523

406.5

1.553

486.7

1.3S0

Prism No. 2. Angle 4' 52".8.

A

M

Y

M

668.0
658.1
524.8

2.23
2.34
1.12

51S.3
514.2

504.8

1.15
1.15
1.19

Prism No. 3. Angle 23' 59". 7.

A

M

732.0
688.0

2.027
2.170

Y

501.8
495.8
489.6

U

1.27
1.28
1.35

Prism No. 4. Angle 1' 17".2.

663.6

M

2.31

Prism No. 5. Angle 24". 7.

A

M

A

M

A

M

A

M

667.5

2.26

610.0

2.14

589.0

1.65

564.0

1.30

646.5

2.35

607.0

2.06

589.0

1.59

550.5

1.22

633.5

2.30

607.0

1.93

580.0

1.57

540.0

1.12

633.0

2.35

599.5

1.86

580.0

1.59

518.2

1.14

623.5

2.33

597.0

1.79

568.0

1.45

506.5

1.22

610 0

2.10

274

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table VII — Continued.
Prism No. 11. Angle 32". 7.

X

M

X

M

X

M

X

M

606.2
599.2

1.88
1.81

518.0
486.5

1.12
1.33

561 0
589.5

1.27

1.58

531.0
518.3

1.13
1.13

Prism No. 13. Angle 51\7.

Prism No. 14. Angle 21' 3".8.

X

H

X

M

622.8
589.5

2.25
1.67

723.6
723.6
423.0

2.014
2.020
1.507

Prism No. 15. Angle 2' 10M.

733.0
683.0
672.0
657.0

u

X

U \

X

M

2.01

655.5

2.32

469.0

1.40

2.19

502.0

1.24

451.0

1.51

2.25

486.5

1.37

441.0

1.50

2.32

(b) Investigations in the Ultra Violet. — The dispersion hav-
ing been measured visually with the spectrometer as far into
the violet region as was possible, the photographic method em-
ployed by Pniiger1 was adopted to extend the work into the
ultra violet. The arrangement of the apparatus is seen in fig-
ure 5 except that sunlight was used instead of the light from
the iron arc.

A solar spectrum thrown by a Rowland concave grating was
received upon a photographic plate. Between the grating, E,
Fig. 5, and the plate, F, was placed an opaque screen, H, pro-
vided with a rectangular aperture over which was fastened the
glass plate supporting the cyanin prism. A strip of black pa-

^Pfluger, Wled. Ann. LXV., p. 206.

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN.

275

per, furnished with two small apertures, was mounted over the
plate, one aperture exposing the prism, the other, clear glass.
Thus, the light arrived at the sensitive plate by two paths, one
direct and the other deviated by passing through the cyanin
prism. Therefore, two sets of the Fraunhofer lines were found

------31'

Fig. 5.

on the plate, of which two sample photographs are seen in plate
19, figures 1 and 2. The upper set of lines was formed by
rays coming through the prism and the lower set by the direct
path. For making these photographs the angle of the prism was
2' 51.5", the distance from the prism to the plate was 177.6 c. m.,
while the time of exposure for the direct ray was three minutes
and for the other seven minutes.

The distance between a given line in one set and the corres-
ponding line in the other set was measured by a filar micrometer
attached to the eye-piece of a microscope. Let X be this dis-
tance in centimeters ; let d be the distance from the plate to the
prism in centimeters, and let a be the angle of the prism
in seconds of arc, then the index of refraction for the wave
length used is given by the following formula : —

, , X 360
w=1 + 2lFd^

(32).

276

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

By this method the indices given in Table VIII, were calcu-
lated.

Table VIII.

A

M

A

H

422.7

410.0
404.0
395.0

1.530
1.565
1.573

1.606

380.0
372.0

1.60
1.61

1

These values of h- are indicated on Plate 16 by crosses and
the values obtained with the spectrometer by circles.

To continue the work in the fall and winter, when cloudy
weather made sunlight unavailable, an electric arc formed
between an iron rod and a rapidly rotating iron disk, was sub-
stituted for the sunlight. The bright lines in the iron spec-
trum gave the same results as the Fraunhof er lines. With light
of wave length shorter than 368 p /u., passing through the
cyanin prism, no effect could be produced on the sensitive plate
although a five hours continuous exposure was made. To in-
crease the intensity of light when passing through the cyanin,
the prism was moved from H to D, eight centimeters behind the
slit, C (Fig. 5).

With this arrangement of the apparatus photographs were
taken and the results are shown in figures 3, 4, 5, and 6 of
plate 19. Light coining by the direct path made the upper
set of lines, while the part coming through the cyanin formed the
lower set. In figure 3 the time of exposure for the upper set*
was forty seconds, and for the lower, seventy seconds. For the
longer waves the intensity of the two sets of lines in this pho-
tograph is almost the same, but beyond 368 ^ ^ no lines appear
in the lower set. The cyanin evidently absorbed the energy of
wave lengths shorter than 368 n /*. The presence of this ab-
sorption band in the cyanin and the approach to the absorption
band in the glass beginning at 335 p i*. is seen in figure 4 of
plate 19. The time of exposure in the photograph of the lat-
ter, by the direct ray, was forty seconds, and through the cyanin
five minutes.

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN.

277

To show the similarity between this effect and the action due
to the absorption in the green, figures 5 and 6 of plate 19 were
taken. In the former the time of exposure for the direct ray-
was forty-five seconds and for the cyanin five minutes. This
gives approximately the same intensity for the lines of shorter
wave length in the photograph, but for the longer wave no im-
pression is seen in the lower band. Figure 6 is the same as
figure 5 save the time of exposure, which in this case was forty
seconds for both sets. By comparing the wave lengths with
the absorption curve it is seen that the photographs of figures
5 and 6 are at the edge of the absorption band in the yellow.

Fig. 6.

'(c) The Method of Crossed Prisms. — In Newton's method
of crossed prisms we have a beautiful means of showing the phe-
nomenon of anomalous dispersion, for by it we can bend a
straight, continuous spectrum into a curve identical in every re-
spect with the dispersion curve obtained by measurements with
the spectrometer. The method was used by Kundt in the course
of his investigations on anomalous dispersion. This method
furnishes qualitative data only, but the fact that the curve of
dispersion is directly photographed gives value to the results.
The general arrangement of the apparatus is seen in figure 6.

278 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

The light of an arc lamp, A, was focused on the slit of the spec-
trometer, C, and parallel rajs coming from the collimator passed
through a water prism, T, and falling on an achromatic lens, F,
of long focus (a telescope lens of six feet focus) formed' a
sharply denned spectrum, V — E, on the photographic plate, H.
In front of the objective, F, was placed a cyanin prism, E, with
its refracting edge horizontal and turned down. This prism
deviated all the rays upwards before they entered the lens, F,
thus elevating the image on the photograph. Since the devia-
tion is due to the fact that light is transmitted slower in cyanin
than in air, and that the velocity of transmission is a function
of the wave length, therefore, the elevation of light of any wave
length will be proportional to ^ — 1 where /j. is the index of re-
fraction for the given wave length. Consequently, if the spec-
trum produced by the water prism is considered to be normal
then the crossed prism spectra produced by the cyanin prism
as described above, is a curve identical in every respect with
the curve of dispersion calculated by the direct spectrometer
method and shown graphically in the curve of plate 16. Ery-
thro plates were used and the more intense action of the blue
and violet was modified by the introduction of an Aurantia
color screen or filter, D. In this way fully exposed photographs
were obtained of the dispersion curve from the extreme red to
the violet. The results are seen in figures 1-6 of plate 20. For
figure 1 the lower straight band was made by a direct exposure,
while the curved strips above are parts of the same spectrum
after having passed through the cyanin prism. The angle of
the prism was 17' 1.0", and the time of exposure, by the direct
path, was twenty seconds, while through the cyanin it was one
hour. The yellow part of the spectrum is absent, the prism
absorbing all the energy of this wave length. For figures 2 and
3, the same method of procedure was pursued, and these photo-
graphs are inserted to show the effect of the Aurantia color
screen, D. The angle of the cyanin prism used for these photo-
graphs was 17' 3.8". For figure 3 no screen was employed ; for
figure 1 the light was passed through a screen of medium thick-
ness, while for figure 2 a rather dense filter was used. The haze

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN. 279

appearing in figure 3, where no color screen was used, is entirely
absent in figures 1 and 2, while the form of the curve is apparent
in all. Cyanin has a very strong absorption band in the yellow,
and to let any light through in this part of the spectrum very
thin prisms must be used. In figure 4 of the same plate is seen
a photograph of a crossed prism spectrum when the cyanin
prism was thin enough to let light of all wave lengths pass
through. The refracting angle was only 24.7", so the deviation
is small, but the continuity of the curve is evident. "No expo-
sure was made by the direct path to avoid overlapping of the two
spectra. A photograph of a similar continuous, crossed prism
spectrum for a cyanin prism of 2' 51.6" refracting single, is
seen in figure 5 of the same plate, in which the deviations are
proportionally larger than in figure 4, and the form of the curve
can easily be followed through the absorption band. In figure
6 the results are seen of four successive exposures through a
cyanin prism of 28'30" refracting angle. The great disper-
sive power of the dye is apparent and although the yellow is ab-
sent the rest of the curve agrees very well with the dispersion
calculated by direct spectrometer readings. The haze in the
green is due to diffraction ; the angle of the prism was so large
that only a very narrow edge was transparent to the green and
this produced the ordinary narrow aperture effect.

(d) The Interferometer Method. — The previous work has for
its basis the deviation of a beam of light by a cyanin prism.
The index of refraction can also be found by measuring the re-
tardation produced by a thin film. To make uniform films of
cyanin the crystals were dissolved in absolute alcohol and the
resulting solution filtered. This solution was then kept in an
air-bath at a temperature between 35° and 40° C. Pieces of
plate glass, after being carefully cleaned and heated to the same
temperature, were dipped into the solution, and placed on edge
to dry in the air-bath. The thickness of the film depends on
the concentration of the solution, and as the alcohol evaporates
rapidly in the air-bath, films of continually increasing thick-
ness are obtained by dipping in fresh plates from time to time.

280

BULLETIN OF THE UNIVERSITY OP WISCONSIN.

To secure good films it is important to use "absolute" alcohol
and to keep .the temperature inside the given limits throughout
the operation. The retardation produced by the film was meas-
ured with a Michelson interferometer (F of figure 7), photo-
graphs being made of the displaced fringes. The interfer-
ometer wras illuminated with monochromatic light obtained from
the direct vision spectroscope, C, as described in the first part
of this paper. From one-half of one of the coated glass plates
the cyanin film was carefully removed, the remainder of the film
having a straight edge down the center of the plate. This plate,
H, was placed between the movable mirror, M, of the interfer-
ometer and the half silvered plate, P, with the straight edge of
the cyanin film vertical, the instrument having been previously
adjusted for horizontal fringes. A plate of clear glass, K, of
thickness equal to that of the coated plate was placed in front of
the other mirror, L, of the interferometer as a compensator.

M
H

CO" •

\M

Fig. 7.

The fringes formed by the interference of rays coming through
the cyanin were displaced relatively to those formed by rays
coming through the clear portion of the plate. In order to fa-
cilitate the determination of the displacement the, fringes were
photographed by means of a camera at Q. The camera was so
arranged that by moving the back portion slightly, successive ex-
posures could be made on the same plate, showing the relative
displacements of the fringes for all values of /* from the ex-
treme red to the ultra violet.

Since the retardation is a function of the wave length, the dis-

MAGNUSSON — ANOMALOUS DISPERSION OF CTANIN. 281

placement between the two sets of fringes varies when the wave
length of the light used is changed. The light passing through
the slit, D, was changed systematically for the successive ex-
posures, so that in the series of photographs shown on plates 21
and 22 a complete record of the retardation throughout the spec-
trum is secured.

The film (No. I), used in preparing the series shown in fig-
ure 1 of plate 21, was very thin (about .00012 mm.) and per-
fectly transparent throughout the absorption band. The white
mark on the sides of the fringe systems was made later to show
which pair of fringes belong together. The number given be-
low each exposure is the wave length in fi ft units of the light
used in each case.

The series given in figure 2 of plate 21 shows the retardation
produced by a somewhat thicker film (about .00017 mm.) not
quite as transparent in the region of the absorption band as the
first. The third film (No. Ill), used in the preparation of
the first figure of plate 22, was much thicker (about .00071
mm.) and quite opaque for yellow or yellowish green light.
Consequently, no fringes were formed in this part of the spec-
trum by the light passing through the cyanin film.

To continue further into the ultra-violet a Rowland grating
was substituted for the spectroscope. Using film No. II, a new
series was taken on the blue, violet, and ultra-violet, the results
being shown in the second figure of plate 22. Repeating th&
same series and using film No. Ill, the photograph shown in
figure 3 of the same plate was obtained.

In these photographs it is to be noticed that beyond
A = 345.6 no fringes appear. This is due to the absorption,
of shorter waves by the glass. Further, below A = 374.2, the
intensity of the fringes in both halves of each exposure is prac-
tically the same, showing that the cyanin film in this part of the
spectrum was perfectly transparent. Between these lines,
X = 374.2 and A = 345.6 that part of the light which had the-
cyanin film in its path is much fainter for the larger waves and
disappears altogether before reaching the absorption band in
the glass. This corroborates previous observation and proves
3

282 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

conclusively that cyanin has an absorption band in the ultra-
violet.

To calculate the refractive index from the photographs shown
on plates 21-22, it is necessary to know which pair of lines be-
long together. With monochromatic light it is impossible to
tell whether the displacement is half a fringe or one and a half,
or any number of whole fringes more, but if white light is em-
ployed and both paths are of equal length there appears a cen-
tral dark fringe, bordered by about a dozen colored fringes sim-
ilarly placed with reference to the central dark fringe. This
dark fringe is the only one in the whole system that can be iden-
tified. Substituting white light in front of slit, D, and having
film No. Ij on the path of the interferometer, a photograph was
taken. The result is shown in a in figure 7 of plate 20. When
looking at the fringes direct it was plain that the fringes marked
on the photograph belonged together. Using film No. II, a pho-
tograph seen in b, figure 7 (plate 20) was taken. The photo-
graph does not show very plainly which pair of lines go to-
gether, but by looking at the fringes directly with the colors
present those marked in the figure were easily determined to
be part of the same fringe. The third exposure c in the same
fignire was taken with film No. Ill in the interferometer. The
strong absorption of this film made the resulting figure hard to
distinguish so that even when the colors were seen directly, it
was difficult to tell which was the central dark fringe in the
part passing through the cyanin. Several observers, however,
independently judged the pair marked in the figure to be cor-
rect.

The index of refraction can be found by the usual formula
for thin films: —

nA
« = 1 + Te (33>-

where fi is the index for wave length X, n, the number of
fringes by which the central fringe is displaced, and e, the thick-
ness of the film. The measurement of e is difficult and the per-
centage error is large when a film is very thin, as is the case in

MAQNUSSON — ANOMALOUS DISPERSION OF CYANIN. 283

these experiments. Therefore, it is desirable to secure a ratio
between the indices for the different wave lengths and find the
index for some one wave length by another method.

Let u equal index of refraction for A.

Let Mi equal index of refraction for Ax.

Let n equal displacement of fringes for wave length A in terms of that
same wave length.

Let n, equal displacement of fringes for wave length At in terms of that
same wave length.

Then: n At : n At :: u — 1: ji. — 1.

Solving for //1 :

(H — 1) nx Ax
*i-l + n~A (34).

This method is advantageous when the indices for portions of
the spectrum, as in the absorption band for cyanin, are difficult
to measure by other methods. The displacements n on the
photographs were measured by means of a filar micrometer at-
tached to an eye-piece magnifying about twenty diameters.

Column a in Tables IX-XII gives the width of a fringe,
for the given wave length, on the photograph in terms of divi-
sions on the micrometer screw. The width of the displacement
in the same units is given in column b. Hence i equals n,
the displacement in terms of fringes of the wave length used.

284

BULLETIN OP THE UNIVERSITY OP WISCONSIN.

Table IX.

X

a

b

n

nA

M

705.5

166.0

82.0

.494

349

2.02

669.5

160.8

100 4

.624

418

2.21

654.9

154.3

103.2

.670

439

2.28

640.1

152.7

107.8

.706

452

2.31

625.8

151.7

104.8

.690

430

2.25

613.2

179.0

84.7

.576

353

2.03

599.8

145 6

74.0

.506

306

1.89

589.6

144.0

59.3

.412

243

1.71

579.0

141.4

52.0

.368

213

1.62

569.5

137.4

42.3

.307

175

1.51

560.7

136.0

28.0

.206

115

1.33

552.4

133.0

24.8

.186

103

1.30

536.9

129.8

12.6

.097

053

1.15

523.3

127.1

16.0

.125

066

1.19

511.0

124.6

20.0

.164

068

1.25

500.0

122.6

28.6

.233

117

1.34

490.5

119.5

33.5

.280

137

1.39

480.9

117.4

34.2

.291

141

1.41

473.6

115.6

37.6

.326

154

1.45

466.1

113.9

39.8

.349

163

1.47

460.5

113.2

40.2

.355

165

1.48

453.0

111.5

42.6

.381

173

1.50

445.0

110.1

44.0

.399

178

1.52

433.0

107.3

48.0

.447

194

1.55

422.9

103.0

51.0

.495

209

1.59

414.8

101.6

51.8

.501

211

1.61

409.1

100.4

52.0

.518

212

1.62

399,8

97.9

52.2

.533

213

1 62

394.5

98.0

52.4

.535

213

1.62

892.1

97.7

54.0

.551

216

1.63

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN.

285

Table X.

A

a

b

n

nA

M

492.5

129.9

36.6

.281

142

1.39

464.8

119.9

48.6

.405

142

1.52

436.5

110.5

49.2

.445

194

1.54

407.8

106.5

60.2

.565

230

1.62

380 0

101.8

63.2

.620

235

1.65

374.2

99.3

67.8

.701

262

1.70

368.5

97.5

70.0

.718

264

1.73

364.6

96.9

71.0

.732

267

1.74

362.7

96.1

72.1

.750

271

1.75

357.5

92.6

73.0

.770

275

1.76

The two photographs used for tables IX and X were taken
with the same cyanin film in one path of the interferometer.
The relation between fi and a as given in tables IX and X is
shown graphically in the curve of plate 17 by the full line, while
the dispersion curve obtained by direct spectrometer readings is
indicated by the broken line. These curves, obtained by en-
tirely independent methods, agree very well, and the difference
is probably due to a change in the properties of the substance
in the two conditions, for the cyanin was fused in the one case
and deposited from an alcoholic solution in the other. It is im-
portant to note the rapid rise in the curve when the absorption
band in the ultra violet is approached, as it shows a similarity
to the increase in the refractive index as the absorption band
fn. the yellow is approached from the red end of the spectrum.

The results from measurements made on the photograph
shown in figure 1 of plate 22 are given in table XL

286

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Table XI.

X

a

b

n

nX

M

705.5

196.0

442.0

2.26

159

2.11

669.5

182.2

489.2

2.68 •

179

2.25

654.9

177.1

517.4

2.92

191

2.34

640.1

173.4

538.0

3.10

198

2.38

523.3

143.7

82.8

0.576

301

1.21

511.0

138.0

114.0

0.826

422

1.29

500.0

135.6

135.3

0.996

498

J .36

490.5

134.6

151 6

1.125

553

1.38

480.9

129.6

160.6

1.239

596

1.42

473.6

125.0

161.4

1.290

611

1.43

466 1

124.6

169.2

1.357

632

1.44

460.2

124.4

173.0

1.424

655

1.46

453.0

125.2

185 4

1.480

671

1.47

445.0

126.0

188.0

1.480

664

1.4T

443.0

123.3

194.0

1.570

697

1.49

422.9

116.4

197.0

1.687

713

1.50

444.8

114.0

201.0

1 760

731

1.51

409.1

110.0

204.0

1.930

770

1.54

394 3

105.0

207.4

1.970

778

1.55

392.1

104.9

213.2

2.030

795

1.55

For figure 2 of plate 22 the readings and calculated results
are given in table XII.

Table XII.

X

a

b

n

nX

U

492.5

144.7

197.8

1.36

672

1.40

464.8

132.3

224.6

1.69

789

1.47

436.5

119.2

241.6

2.02

882

1.53

407.8

113.6

245.2

2.16

880.

1.53

380 0

111.6

254.2

2.28

865.

1.52

374.2

109.9

257.6

2.29

857.

1.52

368.5

107.4

262.0

2.44

899.

1.54

364.6

105.5

266.0

2.52

923.

1.55

362.7

104.2

269.9

2.59

940.

1.56

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN. 287

The two photographs used for tables XI and XII were taken
when cyanin film \'<>. 1 1 1 was in one path of the interferometer.
The relation between /a and a, as given by tables XI and
XII, is shown graphically by the line in plate IS, while the
broken line represents the results obtained by direct spectrometer
readings. The fringes in figure 1 of plate 22 are not quite
parallel, and hence the errors in measuring a and b are
larger, therefore the results for this film are not as good as for
film Xo. II.

Conclusion. — It was originally intended to attempt a more
rigorous proof of the Ketteler-IIelmholtz dispersion formula,
by using more accurately determined values of the refractive
indices of cyanin for waves of various lengths. Pfliigers work
while confirming the formula for the visible part of the spec-
trum, showed discrepancies in the ultra violet and extreme red.
He suggests that these discrepancies, at least in the ultra violet,
may be caused by the presence of an ultra violet obsorption band.
This band has unquestionably been found, but until its charac-
teristics have been more thoroughly determined (a matter re-
quiring a large amount of further experimental work) any at-
tempt to apply the new values to the formula would be useless.

The most important results which have been obtained by this
work may be summarized as follows:

1st. A fairly accurate determination of the dispersion curve
for cyanin from the extreme red well into the ultra violet.

2d. The conclusive evidence furnished by the photographs
taken with the interferometer, of the continuity of the curve
through the absorption band of cyanin.

3d. The discovery of a new absorption band in the ultra vio-
let spectrum of cyanin, the character of which will have to be
accurately determined before any conclusive proof of the Ket-
teler-Helmholtz dispersion theory can be furnished by measure-
ments upon this substance.

This work was undertaken two years ago, at the suggestion
of Professor R. W. Wood, and is a continuation of a series of

288 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

experiments made by him in the previous year. The experi-
ments have been performed under his direction, and I take this
opportunity to acknowledge indebtedness to him for many ideas
and suggestions and for much assistance.

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MAQNUSSON — ANOMALOUS DISPERSION OF CYANIN. 289

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1875. L. Mathiesen, "Ueber die Dispersion der Earben in
Gasen." Z. S. fiir Math. u. Phys. XX., 92-96.

1875. L. Lorenz, "Experiment-ale og theoretiske Undersogel-

ser over Legemernes Brydningsforhold." Vi-
densk. Selsk. Skr. (5), No. 8, X., 485-518.

1876. E. Ketteler, "Versuch einer Theorie der (anomalen)

Dispersion des Lichtes in einfach und doppelt brech-
enden Mitteln." Carl's Rep. XII., 322-361 ; Phil.
Mag. (5), II., 332-345, 413-421, 508-522.
1876. E. Ketteler, "Zur Theorie der Dispersion und Absorp-
tion des Lichtes in doppeltbrechenden Mitteln."
Pogg. Ann. Erg. VIIL, 444-474.

1876. W. Wernicke, "Ueber die Bestimmung der Constanten

fiir die Absorption des Lichtes in metallischen Sil-
ber." Pogg. Ann. Erg. VIIL, 65-82.

1877. E. Ketteler, "Zum Zusammenhang zwischen Absorp-

tion und Dispersion." Pogg. Ann. CLX., 466-486.
1877* Hurion, "Recherches sur la dispersion anomale." Ann.
de l'ecole normale (2), VI., 367-412; Beibl.
(1878), 79-86.

1877. E. Lommel, "Theorie der normale und anomale Disper-

sion." Ann. d. Phys. (2), III., 339-356.

1878. E. Ketteler, "Das Dispersionsgesetz." Wied. Ann.

(2), VII., 658-670.
1878. E. Lommel, "Ueber eine zweiconstantige Dispersions-
formel." Wied. Ann. (2), VIIL, 628-634; Carl's
Rep. XV., 768-770.

292 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

1878. G. Schebujeff, "Zur Dispersiontheorie des Lichtes."
Journ. d. russ. Phys. Chem. Ges. XI., Phys. Theil,
p. 103.

1878. G. Sieben, "Untersuchungen iiber die anomale Disper-

sion des Lichtes." Wied. Ann. VIII., 137-157.

1879. Thollon, "Minimum de dispersion des prismes ; achro-

matisme de deux lentilles de meme substance." C
E. LXXXIX., 93-96.

1879. A. Lomenl, "Bemerkungen iiber die Bestimmung der
Dispersionconstante." Beibl. III., 272-273.

1879. De Klercker, "ITeber das anomale Spektrum de3

Lichtes." C. R. LXXXIX., 734-736. Beibl.
IV., 273. Phil. Mag. (5), VEIL, 521-572.

1880. E. Ketteler. "Das Dispersionsgesetz." Carl's Rep.

XXL, 221-231; Fort. d. Phys. XXXVI., 379.

1880. O. Hesse, "Untersuchungen iiber das Dispersionsge-

setz." Fort. d. Phys. XXXVI., 381 ; Wied. Ann.
XL, 871-908.

1881. E. Lommel, "Ueber das Dispersionsgesetz." Wied.

Ann. (2), XIIIV 353-360.

1881. E. Ketteler, "Einige Anwendungen des Dispersions-

gesetz auf durchsichtige, halbdurchsichtige und un-
durchsichtige Mittel." Fort. d. Phys. XXXVIL,
375; Wied. Ann. (2), XII., 363-380.

1882. Guoy, "Sur la propagation des ondes lumineuses en

egard a la dispersion." Fort. d. Phys. XXXVIII.,
25; Journ. de Math. (3), VIIL, 335-336.
1882. De Klercker, "Untersuchungen iiber die prismatische
Dispersion des. Lichtes." Fort. d. Phys.
XXXVIII., 38. Bihang Sv. Vet. Akad. Handl.
VIL, 1-55.

1882. A. Wuellner, "Zur Dispersion farblos durchsichtiger
Medien." Wied. Ann. XVIL, 580-587; Fort. d.
Phys. XXXVIII., 39.

MAGNUSSON — ANOMALOUS DISPERSION OF CYANIN. 293

1882. V. v. Lang, "Bestimmung der Brechungsexponenten
einer concentrirter Cyaninlosung." Wien. Ber.
(2), LXXXIV., 361-380; Fort. d. Phys.
XXXVIII., 40.

1882. G. Sieben, "Untersuchung iiber die anomale Dispersion
des Lichtes in concentrirten alkoholischen Cyanin-
losungen." Carl's Rep. XVIII., 737-747; Fort,
d. Phys. XXXVIII., 40.

1882. Pulfrich, "Bestimmung des Brechungsquotienten einer
concentrirten Cyaninlosung." Wied. Ann. XVI.,
335-348. Fort. d. Phys. XXXVIII., 40.

1882. C. Christiansen, "Ueber die Messung des Brechungs-

verhaltnisses gefarbter Fliissigkeiten." Nature,
XXVIIL, 308. Wied. Ann." XIX., 256-267 ;
Fort. d. Phys. XXXVIII., 42.

1883. E. Ketteler, "Optische Controversen." Wied. Ann.

XVIIL, 387-421, 631-663.
1883. W. Voigt, "Ueber die Grundgleichungen der optischen

Theorie des Hrn. E. Ketteler." Wied. Ann. XIX.,

691-704; Fort. d. Phys. XXXIX,, 11.
1883. E. Lommel, "Zur Theorie des Lichtes." Wied. Ann.

XIX., 908-914.
1883. W. Voigt, "Zur Theorie des Lichtes." Wied. Ann.

XX., 444-452.
1883. L. Lorenz, "Theorie der Dispersion." Wied. Ann.

XX., 1-21.

1883. De Klercker, "Eecherches sur la dispersion de la

lumiere." C. K XCVIL, 707-708. L. Electri-
cian, XL, 555.

1884. W. Voigt, "Ueber die Theorie der Dispersion und Ab-

sorption speciell iiber die optischen Eigjenschaften

des festen Fuchsins." Fort. d. Phys. XL., 19 ;

Wied. Ann. XXIV., 144-156.
1884. E. Ketteler, "Zur Dispersionstheorie des Lichts."

Wied. Ann. (2), XXL, 199-208; Fort. d. Phys.

XL., 28.
"Zur Dispersion des Quarzes." Wied. Ann. (2), XXL,

438-452.

294 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

1884. P. Jaerisch, "Dispersiontheorie." Fort. d. Phys. XL.,
30. Hamb. Mitth., 59-60.

1884. G. Sieben, "Lleber die Abhangigkeit der Brechungsex-

ponenten anomal dispergirender Medien von der
Concentration der Losung nnd der Temperatur."
Wied. Ann. XXIII., 312-343.

1885. R. T. Glazbrook, "Report on Optical Theories." Brit.

Assoc. (1885), 157-162; Nature, XXXIII., 18-20.

1885. E. Ketteler, "Theoretische Optik." Beibl. IX., 763.

1886. J. W. Bruehl, "Experimentelle Priifung der alteren

und der neueren Dispersionformeln." Beibl. XL,
244 (1887). Chem. Ber. XIX., 2821-2837 ; Fort.
d. Phys. XLIL, 33.

1887. F. Kolacek, "Versuch einer Dispersionserklarung vom

Standpunkte der elektromagnetische Lichttheorie."

Wied. Ann. XXXII., 244-255, 429-439.
1887. E. Ketteler, "Zur Handhabung der Dispersionsform-

eln." Wied. Ann. XXX., 299-316; Jour, de

Phys. (2), VII., 130-131.
■ "Zur Dispersion des Steinsalzes." Wied. Ann. XXXI.,

322-326; Jour. d. Phys. (2), VII., 131-132.

1887. A. Winkelmann, "Xotiz zur anomale Dispersion gliih-

ender Metalldampfe." Wied. Ann. XXXIL, 439-
442; Jour. d. Phys. (2), VII., 132 (1888).

1888. F. Kolacek, "Beitrage zur electromagnetische Licht-

theorie." Wied. Ann. XXXIV., 673-711.

1888. R. T. Glazebrook, "On the application of Sir William
Thomson's Theory of a Contractile Aether to Dou-
ble Refraction, Dispersion, Metallic Reflexion, and
other Optical Problems." Phil. Mag. XXVI.,
521-540.

1888. E. Wilson, "The Law of Dispersion." Phil. Mag.
XXVI., 385-389.

1890. A. Breuer, "Uebersichtliche Darstellung der mathe-
matischen Theorien der Dispersion des Lichtes."
Hannover, Bachmeister, 50 pp. Beibl. XIV., 971.

MAQNUSSON — ANOMALOUS DISPERSION OF CYANIN. 295

1S90. A. Wixkelmanx, "Zur anoraale Dispersion gefiirbter
Glaser." Wied. Ann. XL., 661.

1891. W. Voigt, "Zur Theorie des Lichtes." Wied. Ann.

XLIIL, 412.

1892. D. A. Goldiiammer, "Die Dispersion und Absorption

des Lichtes nach der electrischen Lichttheorie."
Wied. Ann. XLVIL, 93.

1892. A. Breuer, "Uebersichtliche Derstelhing der math.

Theorien iiber die Dispersion des Lichtes." II.
Theil, "Anomale Dispersion." Beibl. XVI., 273.
Erfnrt, Bachmeister, 54 pp.

1893. II. V. IIelmiioltz, "Electromagnetische Theorie der

Farbenzerstrenung." Wied. Ann. XLVIIL, 389,
723; London Electrician, XXXVIL, 404 (1896).

1893. E. Ketteler, "Notiz, betreffend die Moglichkeit einer
zngleich den elastiche-optischen wie den electro-
magnetischen Principien entsprechenden Dasper-
sionsformel." Wied. Ann. XLIX., 382.

1893. S. Bloch, "Sur la dispersion anomale." Beibl. XVII.,
1046; C. R. CXVL, 746-748.

1893. H. Kayser, und C. Runge, "Dispersion der Luft."
Wied. Ann. L., 293.

1893. Du Bois, "Brechung und Dispersion der Metalle."

Wied. Ann. XLVIIL, 785.

1894. F. Paschen, "Die Dispersion des Fluorits und die Ket-

teler'sche Theorie der Dispersion." Wied. Ann.
LIIL, 812, 301, 337.
1894. H. Rubens, "Pnifung der Ketteler-Helmholtz'schen
Dispersionsformel." Wied. Ann. LIIL, 267 ; LI.,
381.

1894. H. Th. Simon, "Dispersion ultraviolettes Strahlen."

Wied. Ann. LIIL, 542.

1895. H. Rubens, "Die Ketteler-Helmholtz'sche Dispersions-

formel." Wied. Ann. LIV., 476.
1895. R. Reiff, "Zur Dispersionstheorie." Wied. Ann. LV.,
82.

296 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

1895. Frantz de Colnet d'Huardt, "Ausdehnung der Max-

well'schen Gleichungen auf die Dispersion." Beibl.
XIX., 58.

1896. A. Pflueger, "Anomale Dispersionkurve einige fester

FarbenstofTe." Wied. Ann. LVL, 412.

"Zur anomale Dispersion absorbirender Substanzen."

Wied. Ann. LVIIL, 670.
1896. B. Walters, "Ueber die Brechungsexponenten des fes-

ten Fuchsins." Wied. Ann. LVIL, 394.
1898. O. Heaviside, "Dispersion." London Electrician,

XXXVII., 470.
1898. A. Pflueger, "Priifung der Ketteler-Helnilioltz'scben

Dispersionsformeln an den optischen Konstanten

anomaldispergirender, fester Farbstoffe." Wied.

Ann. LXV., 173-225.

uPriifung der Cauchv-schen Formeln der Metallreflexion

an den optischen Konstanten des festen Cyanins."
Wied. Ann. LXV., 225.
1898. R. W. Wood, "The Anomalous Dispersion of Cyanin."
Phil. Mag. XLVL, 380-386.

1898. J. H. Vincent, "On the Construction of a Mechanical

Model to Illustrate Helmholtz's Theory of Disper-
sion." Phil. Mag. XLVL, 557.

1899. Lord Rayleigh, "The Theory of Anomalous Disper-

sion." Phil. Mag. XLVIIL, 151-152.

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 47
Science Series, Vol 2, No. s. Pp. 297-3S1

THE THEORY OF ELECTROLYTIC DISSOCIATION AS
VIEWED IN THE LIGHT OF FACTS RECENTLY

ASCERTAINED.

BY

LOUIS KAHLENBERG, M.. Sc, Ph. D ,

Professor of Physical Chemistry.

WITH THE CO-OPERATION OF

Arthur A. Koch, B. S., and Roy D. Hall, B. S.,

Assistants in Chemistry.

Published bi-monthly by authority of law with the approval of the Regents

of the University and entered at the post office at

Madison as seeond-class matter

MADISON, WISCONSIN
February, 1901

@xxlleiin of \\xz tyLnivtv&itv of Q$i*con&in<

(Committee of ^Publication
CHARLES KENDALL ADAMS, President of the University

WILLIAM HEKBERT HOBBS, Editor-ix-Chief

EDITORS

William H. Hobbs, Science Series

Richard T. Ely, Economics and Political Science Series

Charles Forster Smith, Philology and Literature Series

Frederick J. Turner, History Series

J. B. Johnson, Engineering Series

BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 47

Science Series, Vol 2, No. 5, Pp. 297-351

THE THEORY OF ELECTROLYTIC DISSOCIATION AS
VIEWED IN THE LIGHT OF FACTS RECENTLY

ASCERTAINED.

BY

LOUIS KAHLENBERG, M. Sc, Ph. D ,

Professor of Physical Chemistry.

WITH THE CO-OPERATION OF

Arthur A. Koch, B. S., and Roy D. Hall, B. S.,

Assistants i?i Chemistry.

Published bi-monthly by authority of law with the approval of the Regents

of the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
February, 1901

THE THEORY OE ELECTROLYTIC DISSOCIATION AS
VIEWED IN THE LIGHT OF FACTS RECENTLY

ASCERTAINED.

Introduction.

The theory of electrolytic dissociation, as advanced by Arr-
henius1 in 1887, is based primarily upon the facts that the
molecular conductivity of solutions increases with the dilution ;
that substances which when dissolved conduct electricity also
have abnormally low molecular weights in such solutions when
tested by osmotic or freezing- or boiling-point methods; and
that the so-called degree of dissociation may be calculated from
the electrical conductivity, or the results of the molecular weight
determinations. In his original article Arrhenius states that
the phenomena of electrolysis when viewed from the standpoint
of thermodynamics, require the assumption of the presence of
free ions, as was pointed out by Clausius, and that the heats
of neutralization of acids and bases in dilute solutions and the
various physical properties of salt solutions, which are well
known to be additive in character, support the electrolytic dis-
sociation hypothesis. The effect which the publication of that
memorable article of Arrhenius had, need not be dwelt upon at
length here. Suffice it to recall that its author sought to save
van't Hoff's theory of solutions from having but a limited ap-
plication, and at the same time to bring into correlation facts
that had hitherto been entirely isolated. Chemists and phys-
icists alike were astonished by the audacity of the assumption

*Zeit. Phys. Chem. 1, 629 (1887).

300 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

made by this investigator of recognized ability. The theory at
once met with great opposition, notably in England, and it was
by no means received with open arms on the continent. But
the hypothesis inspired experimental investigation, and the re-
sults of this phenomenal activity (which at first centered in Ost-
wald's laboratory at Leipzig, but spread rapidly to other parte
of Germany, to various other countries of Europe and to Amer-
ica) soon silenced opposition in Germany and gradually dimin-
ished the opposition in England. It must not be supposed,
however, that this silence meant that all were convinced. The
silence seemed to result on the one hand because of a recognition
of the futility of the debate with the knowledge of existing
facts, and because of a recognition of, if not an admiration for,
the enthusiasm displayed by the adherents of the theory, — en-
thusiasm that bore fruitful results in experimental investiga-
tions of various physical, chemical, and physiological properties
of solutions, which results were ingeniously interpreted in the
light of the new theory.

It was at first only in the case of aqueous solutions of the or-
dinary acids, salts, and bases that van't HofT's theory of solutions
met its difficulties ; and when Arrhenius pointed out that these
solutions are conductors of electricity, and assumed that the dis-
solved substances are electrolytically dissociated into free ions,
these solutions were on this basis shown to support the theory.
Arrhenius calculated the troublesome factor i (which van't Hoff
had found it necessary to introduce to make the behavior of the
above mentioned solutions conform to the gas equation) from
the electrical conductivity on the one hand and from molecular
weight determinations on the other, the resulting figures show-
ing an agreement to within 5 to 15 per cent., according to his
estimation. In view of the few experimental data at hand in
1887 and the fact that many of them had not been determined
with accuracy, the poor agreement of a goodly number of values
at least was readily overlooked in view of the generalities that
the theory sought to bring, generalities which were soon incor-
porated without proper qualifications into text-books. The
electrolytic solutions with which Arrhenius made his compari-

KAULENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 301

eons and deductions were without exception aqueous solutions.
The non-aqueous solutions known at that time were practically
non-conductors of electricity, and in dilute solutions at least
they generally conformed fairly well in their behavior to van't
HofT's theory of solutions. Indeed, it was not until Kaoult be-
gan his famous work on the freezing-points of non-aqueous solu-
tions that it was discovered that molecular weights could be cal-
culated from the lowering of the freezing-point.

In view of the facts then known, the idea gradually gained
ground in the minds of those holding van't HofT's theory and
Arrhenius' auxiliary hypothesis concerning the nature of elec-
trolytes, that non-aqueous solutions in general yield "normal"
molecular weights for the solutes, and that thev are "of course"
non-conductors of electricitv. This notion took root with sur-
prising rapidity and the natural result was that investigations
of electrical conductivity, of electromotive forces and of elec-
trolysis in non-aqueous solutions were entirely neglected. l When
in 1895 I had the great privilege of working in the inspiring at-
mosphere of Ostwald's laboratory, I upon one occasion asked
the genial director of the institute why the electrical conduc-
tivity of non-aqueous solutions was not studied, the reply re-
ceived was, "Die nicht wdsserigen Losungen leiten ja nicht."
So it was hardly a surprise when in 1899 the new edition of
Ostwald's Grundriss der allgemeinen Chemie appeared contain-
ing on pages 390 and 391 the sweeping, unqualified, italicized

statement,

"Jedesmal wenn ein geloster Stoff von den Losungsgesetzen in
solchem Sinne abweicht, dass sein osmotischer Druck (oder die diesem
proportionate Gefrierpunkts- oder Siedepunkts-andrang) grosser ist,
als seinem Molekulargewicht entspricht, so zeigt er auch elektrolytische
Leitfahigkeit und umgekehrt."

It is to be noted that Keychler^s book on physical chemistry—
a much less compendious volume, the English translation of
which appeared early in 1899 — nevertheless contains a very fair

*On the other hand it was at once assumed that free ions exist whenever
a substance conducts electricity with accompanying chemical decomposition,
be that substance a gas, a molten salt, or a solid.

302 BULLETIN OF THE UNIVEKSITY OF WISCONSIN.

consideration of the work that had at that time been accom-
plished in the study of non-aqueous solutions.

Behavior of Non-Aqueous Electrolytic Solutions.

Before entering upon the experimental part of this paper, I
desire to call attention briefly to the import of some of the work
on non-aqueous conducting solutions as bearing upon the theory
of electrolytic dissociation. In the first place many cases have
been found in which the molecular conductivity decreases with
increased dilution. This is true for instance of solutions of
Nal and NaBr in benzonitrile,1 of AgN03 in piperidine2, of
FeCl3 in pyridine,3 of FeCL, in benzaldehyde3 and of CoI2 in
POCI34. In other cases the molecular conductivity at first in-
creases and then again decreases with the dilution, as, for in-
stance, in solutions of FeCL in paraldehyde,3 of CBr3 COOH
in POCI34. Again many solutions have been found in which
the solute according to molecular weight determinations is un-
dissociated, and which nevertheless possess excellent power of
conducting electricity. So AgN03 has a normal molecular
weight5 in pyridine and benzonitrile, and yet it conducts6 fairly
well in these solvents. According to Dutoit and Friderich7
Cdl2, LiCl, Nal, HgCL, and NH^CNS have normal molecular
weights in acetone and yet these solutions are conductors of
electricity. Walden8 has found that KI, Nal, KbI, NH4I and
KCISTS conduct well in liquid S02 and yet have abnormally
large molecular weights in this solvent; while S(CH3)3I,
3SF(CH3)4I have molecular weights in this solvent which hardly
differ from the theoretical more than do the molecular weights
of non-electrolytes examined in S02. Walden himself says

concerning this :

"Ganz unerwartet ist jedoch die doppelte Molekulargrosse fur die

lEuler, Zeit. Phys. Chem. 28, 619 (1899).

2 Lincoln, Jour. Phys. Chem. 3, 457 (1899).

'Kahlenberg and Lincoln, .lour. Phys. Chem. 3, 12 (1899).

* Walden, Zeit. anorg. Chem. 25, 213 (1900).

e Werner, Zeit. anorg. Chem. 15, 1 (1897).

eKahlenberg and Lincoln, 1. c; also Lincoln, 1. c.

7 Bull. Soc. Chim. (Paris) (3) 19, 334 (1898).

8Ber. deut. Chem. Ges. 32, 2862 (1899).

KAHLENBERQ — THEORY OF ELECTROLYTIC DISSOCIATION. 303

t

elektrolyte 4-7, was ganz aus dem Rahmen des Geforderten herausfallt
und nicht ohne Weiteres mit der iiblichen Auffassung vereinbar ist*'.

Franklin and Kraus7 have found that while NEL^C^,
!N"a!N"03, and KI dissolved in liquid ammonia are excellent con-
ductors of electricity, the boiling-points of the solutions, like'
those observed by Walden in S02, are not nearly as high as they
ought to be on the assumption that electrolytic dissociation takes
place. Again lately, Xicolo Castoro1 found by means of the
freezing-point method that AgjNT03, CdCl2, HgCl2, and ZnCl2
have normal molecular weights in urethane. I have made a few
preliminary tests on the first three of these salts which show
that their solutions in urethane are conductors of electricity.
Verv recentlv Lines2 found the molecular weights of succinic,
salicylic, and tartaric acids to be normal in pyridine, according
to the boiling-point method. These acids undoubtedly form
salts which re-dissolve in the excess of the solvent. Preliminary
tests have assured me that all three of these solutions are fairly
good conductors of electricity. The tartaric acid solution con-
ducts best, as might have been expected.

While in many cases the molecular conductivity of non-
aqueous solutions increases with the dilution, this increase is
generally relatively slight. It has generally been impossible to
calculate the degree of dissociation of substances in non-aqueous
solutions from the conductivitv, because in these solutions the
molecular conductivity commonly either diminishes with the in-
crease of dilution, or it increases slightly with the dilution, ex-
hibiting no tendency to reach a maximum, or it remains prac-
tically constant, or soon reaches a maximum with so low a value
that completeness of dissociation can not consistently be as-
sumed. These facts will become evident to the reader by a
perusal of the figures contained in the original articles above
cited. I have already discussed at some length the difficulty of
calculating the degree of dissociation in non-aqueous solutions,3
and shall therefore simply add here that the calculation of the

^az. chim. Ital. 28 II, 317 (1898).

*Jour. chem. Soc. London 79, 261 (1901).

•Jour. Phys. Chem. 3, 395 (1899).

304 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

degree of dissociation from molecular weight determinations is
in the case of non-aqueous solutions also impracticable, because
the molecular weights are, as a rule, normal, or greater than
normal, in spite of the fact that the solutions conduct well and
that the boiling-point constant of the solvent is so high that dis-
sociation certainly ought to be indicated, if present.

It is a well known fact also that molecular weights determined
according to cryoscopic or ebullioscopic methods at times in-
crease with the dilution ; again, at other times, they do not
change much with the dilution ; and at still other times they de-
crease as the dilution increases. The latter behavior only is in
harmony with the theory of solutions and the theory of electro-
lytic dissociation. Furthermore simple substances occasionally
show abnormally low molecular weights and yet their solutions
are not conductors of electricity. This I have found to be true,
for instance, in the case of solutions of diphenylamine in methyl
cyanide, — results as yet unpublished.

The osmotic theory of the galvanic cell, which uses the disso-
ciation hypothesis as a basis, also naturally meets great difficul-
ties when applied to chains containing non-aqueous solutions.1

In the face of these facts the theory of electrolytic dissocia-
tion is untenable in the case of non-aqueous solutions. While
chemists have frequently in conversation admitted this to be
true, I have also often been told, "But in the realm of aqueous
solutions the theory concords with the facts so well". This led
me to investigate the behavior of aqueous solutions somewhat
further.

Experimental Part.

The general plan of the investigation was to determine the
boiling-points of aqueous solutions of typical, common chemical
compounds from low to very high concentrations, in order to see
how the molecular weight changes with the concentration, and
at the same time to measure the electrical conductivity of such
solutions at or near their boiling-points. This would enable one
to make much more accurate comparisons between the values of
the degree of dissociation as calculated from conductivity and

>See Kahlenberg, Jour. Phys. Cheni. 3, 395 (1899). Ibid. 4, 709 (1900).

KAHLENBERG — THEOEY OP ELECTROLYTIC DISSOCIATION. 305

molecular weight than by the but too common practice of com-
paring dissociation coefficients deduced from conductivity re-
sults obtained at room temperature, with those reckoned from
boiling- or freezing-point experiments. The work of making
the conductivity measurements at high temperatures and the
corresponding boiling-point determinations was undertaken by
Mr. Arthur A. Koch, to whose diligence and care the numerous
tables (2 and 12 to 31, inclusive) given below are due. Again
it was part of the plan to measure the conductivity of such solu-
tions at 0° and at the same time to make molecular weight deter-
minations by the cryoscopic method, and then to compare the
degrees of dissociation found according to the two methods.1
All the conductivity determinations at 0° were made by Mr.
Roy D. Hall, the results of whose work are contained in Table
1 below.

The conductivity determinations were made by means of the
usual Kohlrausch method, a telephone being employed. An
Arrhenius resistance cell was used for the dilute solutions, and
a U shaped cell with plantinized electrodes sufficiently far apart
was employed for the concentrated solutions. All of the solu-
tions were carefully made up to the proper volume at the tem-
perature indicated. The measurements at 0° were made in a
bath of melting ice surrounded by another very large bath of
the same nature. In the immediate vicinity of the resistance
cell a delicate thermometer was kept which remained very con-
stant at 0°. At first it was attempted to measure the conduc-
tivity of solutions at 100°, but it was soon observed that small
gas bubbles are so apt to form on the electrodes at this tempera-
ture as to introduce considerable error. It was found that at
95° this particular difficulty is not so prominent, and so the con-

1Bat few conductivity determinations at or near 100° could be found in the
literature. For seven of the salts named in Table 2, Krannhals [Zeit. phys.
Chem. 5, 250 (1890)] determined the conductivity at 99.4°. He did not, however, as
a rule begin with as concentrated solutions as those represented by the corres-
ponding salts in Table 2, and his series are frequently incomplete. As far as
conductivity determinations at 0° are concerned only a few scattered determina-
tions could be found In the literature, which would not have been adequate for
the purpose in hand. Molecular weight determinations of a goodly number of
the salts under consideration are to be found in the literature, but. they do not
cover a sufficient range of concentration for the present purpose.

306 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

ductivity measurements at the higher temperature were made at
95° instead of at 100°. The resistance cell was immersed in a
large paraffine bath whose temperature was carefully regulated
at 95°.

The freezing-point determinations were made with a regular
Beckmann's apparatus of large size, about 40 grams of water
being used in each case. The solutions were cooled only from
two to three-tenths of a degree below their freezing-points, and
the crystallization was each time inaugurated by means of a
point of ice. The boiling-point determinations were made with
a Beckmann's apparatus of about double the ordinary size. Un-
less otherwise stated, appropriate Beckmann's thermometers
graduated to 0.01° (made by F. O. R. Goetze in Leipzig) were
used. It was at first thought best to surround the thermom-
eter with a platinum cylinder in the boiling tube, as recom-
mended by Jones, but it was soon found that this at times causes
slight fluctuations in the boiling-point, apparently due to the
fact that the solution within the cylinder is apt to be slightly
more concentrated than that without.

The water used in the experiments was distilled water con-
densed in a block tin condenser. By drawing air freed from
carbon dioxide through it for a long time its conductivity was re-
duced to 2X10-6 (or somewhat less) at room temperature. The
conductvity of the water has been deducted in each case, after
having been determined at the proper temperature. The sub-
stances used were all of the C. P. variety of standard makes,
generally either Kahlbaum's or Schuchardt's. They were tested
as to their purity and as a rule were recrystallized. When the
salt contained water of crystallization, the amount of this was
ascertained, and the salt was weighed in the crystallized form
for the molecular weight determinations, the crystal water being
added to the solvent in making the computations, so that the
latter are all based on the amount of anhydrous salt in the solu-
tions. For the conductivity determinations the appropriate
quantities of salt (also calculated on the basis of the anhydrous
substance) of course simply had to be made up to the required
volume at the proper temperature.

KAHLENBERO — THEORY OP ELECTROLYTIC DISSOCIATION.

307

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KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 309

In Table 1 are given the results of the conductivity measure-
ments at 0°, while in Table 2 the values obtained at 95° are pre-
sented. The numbers in each case indicate the equivalent con-
ductivity ( Av ) in reciprocal ohms. The value of v indicates
the volume in liters in which a gram-equivalent is contained.

An inspection of Tables 1 and 2 shows that in each case A ^n"
creases with the dilution, which fact has also been observed by
other investigators1 who have determined the conductivity of
these salts at 18° and 25°. The general manner in which the
equivalent conductivity increases with the dilution can best be
seen by charting the results in the form of curves. For the
salts here under consideration, it is true in general that A in~
creases with increase of v in a similar manner in the cases of
salts that are chemically analogous. Thus if curves be charted
in which ordinates represent the volumes and abscissas the con-
ductivities, these curves will have a similar trend in the case of
the chlorides, the same will be true for the nitrates as a group,
and again for the sulphates as a group. At the same time the
curves for the nitrates are very similar to those of the chlorides,
but the sulphates have curves with more of a characteristic trend
of their own. It was deemed unnecessary to present here the
curves for all the salts in Tables 1 and 2. While they have all
been plotted, it will suffice for the present purpose to reproduce
curves of the various types of salts contained in the tables. As
euch typical salts NaCl, BaCl2, MgS04 and AgN03 have been
selected. Figures 1 and 2 show the trend of the curves at 0°
and at 95° respectively, the ordinates representing the cube
roots of the volumes and the abscissas the equivalent
conductivities. The shape of the curves of KC1 and KE is
similar to that of NaCl; the shape of the curves of ZnS04,
MnS04, CdS04, NiS04, CoS04, FeS04, and CuS04 closely
resembles that of MgS04 ; while KN03 and NaN03 have curves
much like that of AgN03. The great similarity between the
curves of the chlorides and those of the nitrates has already been
alluded to. This similarity is clearly shown by the curves rep-

itCompare for instance the tables in Kohlrausch und Holborn,— Das Leitver-
mogen der Elektrolyte.

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 311

resented in the figures. A comparison of Tigs. 1 and 2 shows
that at 95° the MgS04 curve is practically a straight line, and
that the curves of NaCl, BaCl2, and AgN03 also exhibit a
marked tendency to straighten out at the higher temperature.
It should be stated in this connection that the curve for CdS041
preserves more of its convexity toward the axis of abscissas at
95° than do the curves for the other sulphates. Curves that
were charted from data obtained for the same salts at 18° and
at 25° showed a marked similarity2 to those in Fig. 1 (at 0°)
and indicate that the change in the shape of the curves at 0° and
at 95° takes place gradually as the temperature rises. It
should be clearly borne in mind that the curves for even very
closely analogous salts are not perfectly parallel; all that can
be said of them is that they are similar in trend. .

The results of the freezing-point determinations are given in
Tables 3 to 11. The headings of the tables are self-explanatory.
In calculating the molecular weights 18°. 9 was assumed as the
lowering of the freezing-point caused by the presence of one
gram-molecule in 100 grams of water.

Table 3.3

Sodium Chloride (NaCl) Mol. Wt. 58.5.

Am't NaCl in
100 g. Water.4

Lowering of the
Freezing-point.

Molecular
Weight.

1.1956

0.693

32.6*

2.5509

1.512

31.9

2.9707

1.750

32.1*

3.9273

2.300

32.3*

4.9146

2.866

32.4

5.7419

3.395

31.7*

^bis curve is not represented in the figures. The curve for HgClQ— also not
represented— is practically a straight line at 95°.

2 Such similarity has also been pointed out at various times by other observers.

3 The four determinations marked * in this table were made in this laboratory
by Mr. G. M. Wilcox. The other two determinations were made by the writer.

* In this table, and also in the succeeding tables (4 to 31), the computation
of the amount of solute contained in 100 grams of water has been carried ont
to more decimal places than is necessary. Through an inadvertence these num-
bers were not rounded off to fewer decimal places, as they should have been,
especially in the case of the more concentrated solutions.

312

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table 4.

Magnesium Sulphate (MgSOJ Mol. Wt. 120.4.

Am't MgS04 in Lowering of the Molecular

100 g. Water. Freezing-point. Weight.

0.6994 0.154 85.8

1.5173 0.314 91.3

2.5506 0.480 100.4

5.9948 1.006 112.6

6.9618 1.165 112.9

9.2469 1.527 114.5

Table 5.

Zinc Sulphate (ZnSOJ Mol. Wt. 161.5.

Am't ZnS04 in
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

1.6029

0.258

117.4

5.0266

0.625

152.0

8.9621

1.030

164.5

10.9305

1.246

165.8

13.6750

1.493

173.1

16.9351

1.922
Table 6.

166.5

Manganous

Sulphate (MnSOJ Mol. Wt. 151.

1.

Am't MnS04 in
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight

1.9410

0.293

125.2

2.5022

0.361

131.0

5.1208

0.687

140.9

10.8430

1.399

146.5

18.5720

2.591
Table 7.

135.5

Cadmium Sulphate (CdSOJ Mol. Wt. 208.1.

Am't CdSO« in
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

3.0714

0.313

185.5

8.6084

0.742

219.3

15.6400

1.322

223.6

22.647J)

1.968

217.5

26.1200

2.330

211.9

KAHLENBERGt — T

heory of electrolyti
Table 8.

C DI

8SOCIA1

HON. 61c

Nickelous Sulphate (NiS04) Mol.

wt.

154.8.

Am't NiS04 in
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

1.0777

0.189

107.8

2.36*2

0.351

127.3

4.3320

0.557

147.0

5.8966

0.779

143.1

10.4433

1.284

153.7

16.0307

1.984
Table 9.

152.7

Colbaltous Sulphate (CoSOJ Mol

. wt.

155.1.

Am't CoSC% in
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

1.4570

0.209

131.8

2.9824

0.390

144.5

4.9278

0.600

155.2

9.6574

1.067

171.2

14.1430

1.587
Table 10.

168.5

Ferrous Sulphate (FeSOJ Mol.

wt.

152.1.

Am't FeSO, iu
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

2.2709

0.316

135.8

2.6514

0.376

133.3

6.5028

0.794

154.8

8.9803

1.072

158.4

13.8490

1.655
Table 11.

158.2

Copper

Sulphate (CuSOJ Mol.

wt.

159.7.

Am't CuS04 iu
100 g. Water.

Lowering of the
Freezing-point.

Molecular
Weight.

1.8354

0.300

115.6

3.3127

0.405

154.6

6.4435

0.743

163.9

9.2425

0.996

175.4

14.2100

1.569

■

j*..

171.2

314 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Tables 3 to 11 do not contain all the salts represented in
Table 1. The freezing-points of barium chloride solutions have
lately been determined by Jones and Chambers1 between ap-
proximately the concentrations 0.1 and 0.6 normal, as have also
those of chlorides and bromides of other alkaline earths. Table
3, giving the results obtained with NaCl, indicates that for the
concentrations investigated (0.2 to 1.0 normal approximately)
the molecular weight is practically constant. For about 0.2
normal the molecular weight was found to be 32.6, which cor-
responds to a dissociation of 79.4 per cent. ; for an approxi-
mately normal solution the molecular weight. was found to be
31.7, which corresponds to a dissociation of 84 per cent. These
two results represent the extreme variations of the values in
Table 3. For the average value of the six determinations, 32.2,
the dissociation is 81 per cent. According to Table 1 the de-
gree of dissociation (calculated according to the usual formula

— - ) is about 79 per cent, for the 0.2 normal solution and

Aoo

70 per cent, for the normal solution.2 The degrees of disso-
ciation 79 per cent, and 70 per cent, correspond respectively
to the molecular weights 32.7 and 34.4. It is clear then,
that the degree of dissociation for the most dilute solution tested
is found to be the same by freezing-point and conductivity
methods to within the experimental error of the former method.
But the dissociation increases rapidly with the dilution accord-
ing to the conductivity, whereas the freezing-point results show
that it at least remains constant, if it does not diminish with the
increase of the dilution within the limits tested. C. Dieterici3
has shown by his very careful measurements of the diminution
of the vapor tension of NaCl solutions at 0° that between the
limits 0.1 and 1.0 normal the molecular diminution of the
vapor tension decreases as the dilution increases. E. W. Wood4

'Amer. Chem. Jour. 23, 89 (1900).

*In calculating the degrees of dissociation from the conductivity the values
of the conductivity at infinite dilution were taken either directly from the high-
est values given in the table of conduct! vites; or when the trend of the curve
(which was in all cases charted) required it, from the careful extrapolation of
the curve.

8Wied. Ann. 62, 616 (1897).

«Zeit. phys. Chem. 18, 522 (1895).

KAHLENBERG — THEORY OP ELECTROLYTIC DISSOCIATION. 315

found that the degree of dissociation of KC1, while nearly the
same by cryoscopic and conductivity methods at a concentra-
tion slightly above 0.1 normal, increases more rapidly with the
dilution by the latter than by the former method.

In the case of MgS04 (Table 4) the solutions examined
varied in concentration from about 0.1 to 1.5 normal. The de-
gree of dissociation for the most dilute solution being 40 per
cent, and for the most concentrated only 5 per cent. Accord-
ing to the conductivity determinations (Table 1) the corre-
sponding degrees of dissociation are 44 and 22 per cent, re-
spectively. The discrepancy between the dissociation as de-
termined by the two methods, then, while relatively rather small
at first, increases enormously with the concentration within the
limits investigated.

Zinc sulphate (Table 5) shows no dissociation according to
the freezing-point determinations when the solutions contain
a gram-equivalent or more of the salt per liter, and yet zinc
sulphate solutions have an electrical conductivity nearly the
same as that of the equivalent solutions of MgS04 (Table 1).
The most dilute solution represented in Table 5 yielded a molec-
ular weight of 117.4, corresponding to a dissociation of 38
per cent. ; the conductivity method yields about 40 per cent.
For the normal solution, where the dissociation is nil according
to the cryoscopic work, it is 24 per cent, according to the con-
ductivity.

Manganous sulphate (Table 6) at first shows an increase of
molecular weight with the increase of concentration and then
a decrease. This also appears in the case of ZnS04 (Table 5)
though less markedly. Again CdSO* (Table 7) shows this
behavior in a marked degree, while NiS04 (Table 8), CoS04
(Table 9) and CuS04 (Table 11) show it slightly, and possibly
also FeS04 (Table 10). The electrical conductivity of MnS04
solutions increases regularly with the dilution, as does that of
solutions of all the other sulphates investigated. It is clear
that according to the conductivity determinations the dis-
sociation constantly increases with the dilution in the case of
2

316 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

the particular sulphates just enumerated, whereas according
to the cryoscopic determinations, there is at first a decrease
of dissociation with increase of concentration, and then an in-
crease of dissociation with increase of concentration. The
most dilute solution of MnS04 tested (about 0.25 normal) gave
a molecular weight of 125.2, corresponding to 2 per cent, dis-
sociation, whereas the conductivity method yields about 35
per cent. When the molecular weight is 146.5 the dissocia-
tion is 3 per cent., the conductivity indicates 20 per cent.

It is practically useless to make the comparison in the case
of CdS04 (Table T) for the cryoscopic determinations show no
dissociation except in the most dilute solution tested; where-
as, as stated above, the conductivity of the solutions is excellent
and increases regularly with the dilution. The most dilute so-
lution, in which a molecular weight of 185.5 was found would
contain the salt dissociated to the extent of 12 per cent. ; the
conductivity results yield about 30 per cent.

Nickel sulphate is practically undissociated according to cryo-
scopic determinations (Table 8) when the solution is about ten
per cent, strong. The conductivity at about this strength in-
dicates 22 per cent, dissociation. The molecular weight of the
most dilute solution investigated corresponds to 43 per cent,
dissociation^; the conductivity indicates 42 per cent.

In the case of CoS04 the freezing-point indicates no disso-
ciation in a solution about 5 per cent, strong or stronger (Table
9), whereas the conductivity determinations show about 26 per
cent, dissociation when the observed molecular weight is 155.2.
In the most dilute solution the molecular weight found is
131.8 corresponding to 18 per cent, dissociation; the conduc-
tivity indicates about 34 per cent.

According to cryoscopic determinations FeS04 also is un-
dissociated in about six per cent, solutions or over (Table 10).
When the observed molecular weight is 154.8 the conductivity
nevertheless indicates 24 per cent, dissociation. The most dilute
solution shows a molecular weight of 135.8 or 12 per cent, dis-
sociation; the conductivity indicates 30 per cent.

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 317

Copper sulphate is also undissociated in 5 per cent, solutions
or over (Table 11). When the molecular weight observed
equals 163.0, which corresponds to no dissociation, the conduc-
tivity indicates about 22 per cent, dissociation. In the most
dilute solution tested, the molecular weight found, 115.6, corre-
sponds to 38 per cent, dissociation; the conductivity indicates
about 32 per cent.

From the foregoing it is evident that with the exception of
a few instances (and these at certain special concentrations)
the agreement between the value of the degree of dissociation,
as calculated from the freezing-point of the solutions, and that
deduced from their conductivity, must in general be pro-
nounced poor, even in the case of the most dilute solutions
tested ; while in the somewhat stronger solutions there is no
agreement at all, many of the cryoscopic determinations show-
ing no dissociation, whereas the conductivity indicates quite
appreciable dissociation.

Arrhenius1 in his original table presents figures from cryo-
scopic data indicating no dissociation for MgS04, FeS04,
CuS04, ZnS04, and CdS04, whereas the electrical conductivity
(he used the results obtained at room temperatures) showed
considerable dissociation, which agrees substantially with, the
results above recorded for the stronger solutions. Cadmium
iodide, as Arrhenius shows, exhibits a similar behavior. Ar-
rhenius seeks to explain away the discrepancy in the case of
the sulphates mentioned by assuming that the inactive or un-
dissociated molecules in the solutions are polymerized; and
he seeks to base this assumption on the fact that Hittorf2
found the migration numbers of MgS04 and ZnS04 to show
a considerable variation with the concentration, which was also
found to be true — though much more markedly — in the case of
Cdl2, for which Hittorf assumed double molecules in the so-
lution in order to explain the phenomena lie observed. The lat-
ter also clearly states that he applies the same explanation
to the other salts of the magnesia series, for their migration

i\. c.

*Pogg. Ann. 106, 547 (1859).

318 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

numbers also vary considerably with the concentration. This
at first seems to justify perfectly the position taken by Ar-
rhenius. However, the latter has not applied the explanation
to all the salts of the magnesia series, as he ought to, but he
has simply assumed polymerized molecules in the case of those
salts that did not behave according to his theory. He ought
to assume polymerized molecules in the case of MgCl2, for in-
stance, for Hittorf found the migration numbers of this salt
strongly dependent upon the concentration, as he did those of
MgS04. But it happens that to assume polymerized molecules
in the case of MgCL would be very inconvenient for Arrhenius'
theory, as his calculations of the factor i show, and so he did not
make the assumption which he, in order to be consistent, ought
to have made. In the case of CaCl2, BaCl2, Ca (ISTOg^,
Ba(]Sr03)2, Hittorf likewise found the migration numbers
strongly dependent upon the concentration, yet Arrhenius does
not assume polymerized molecules for these, as he ought to, to
be consistent, for these salts agree better with his theory
when such an assumption is not made. To assume polymeri-
zation of the molecules of such salts as MgCl2, CaCl2 and BaCl2
would lead to the greatest difficulty also in harmonizing the
freezing-point results obtained by Jones and Chambers1 with
the dissociation theory ; for they have f ound that the molecular
lowering shows a minimum between the strengths 0.1 and 0.2
normal, and that in concentrated solutions the lowering is as
great or greater than the theoretical lowering, if the com-
pounds were completely electrolytically dissociated. Jones and
Chambers seek to harmonize their "abnormal" freezing-point
lowerings by assuming that the salts form hydrates in the so-
lutions. There can hardly be any doubt that the salts in ques-
tion unite with water to form hydrates ; but when the authors
seek to use this to explain the "abnormally" low freezing-points
of solutions, it might be well to remind them that the dissociation
theory itself was promulgated to explain "abnormally" low freez-
ing-points of solutions, and that since they have found the theory

1Amer. Chem. Jour. 23, 89 (1900). Compare also in this connection Chambers
and Frazer, Ibid. 23, 512 (1900).

KAriLENBERQ THEORY OP ELECTROLYTIC DISSOCIATION. 319

unable to do this and have reached out to the hydrate theory
for help, it mighl be well in the face of the facts to acknowledge
freely the weakness of the dissociation theory and to proceed to
explain the facts on the basis of the hydrate theory alone. If
it be urged that the solutions conduct electricity and therefore
the salts must be electrolytically dissociated, — the answer is,
they must be, only if the dissociation theory be assumed.

Attention must now be directed especially to the careful
determinations of C. Dieterici1, who measured the lowerings
of the vapor tensions of a series of aqueous solutions of elec-
trolytes and non-electrolytes at 0°. He found that for CaCl2
the molecular lowering of the vapor tension diminishes strongly
with increase of the dilution, and then at about 0.1 normal
it again increases with the dilution. He also emphasizes the
fact that the very careful freezing-point work of Loomis2 and
of Ponsot3 shows a minimum of the molecular lowering of the
freezing-point at nearly the same concentration. The work of
Jones and Chambers above cited also corroborates this. Be-
tween the concentrations 0.1 and 1.0 normal, to which Dieter-
ici's work is really limited, he found that for the substances
tested (H3P04, H2S04, NaCl, CaCl2, cane sugar, dextrose
and urea) the molecular lowering of the vapor tension dimin-
ishes as the dilution increases, which is the opposite of that
which the theory of Arrhenius requires. In view of this fact
Dieterici rightfully refrains from even attempting to make
a further comparison between the degree of dissociation as
calculated from the vapor tension measurements on the one
hand and the conductivity on the other. The reader is also
referred to the able critical consideration of the very careful
freezing-point determinations of various investigators which is
contained in Dieterici's article.

Attention is now called to the results of the boiling-point
determinations (Tables 12 to 29). For a number of the most
important salts represented in these tables, two, and in a few

*1. c.

^Wied. Ann. 51, 500 (1894); Ibid. 57, 495 (1896); Ibid. 60, 523 (1897).
•Recherches sur les congelations, Gauthiers and Villars, Paris (1896).

320

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

instances three or four, series of determinations were made by-
Mr. Koch, in order to be perfectly sure of the facts.

Table 12.

Sodium Chloride (NaCl) Mol. Wt. 58.5.

(Series 1.)

Am't NaCl in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

1.1395

0.197

747.7 mm.

33.4

4.1674

0.744

747.1

32.4

5.5246

1.002

747.0

31.9

8.2543

1.553

747.0

30.0

11.0105

2.157

746.9

29.5

15.9109

3.304

746.9

27.8

20.5207

4.495

746.8

26.4

(Series '.

2.)

2.9004

0.499

743.6 mm.

33.6

6.0065

1.082

743.5

32.1

7.1036

1.690

743.5

30.6

12.6259

2.514

743.5

29.0

15.6403

3.231

743.5

28.0

18.5305

4.032

743.5

26.7

20.1309

4.471

(Series

743.5
S.)x

26.0

1.256

0.195

754

33.5

2.500

0.390

754

33.3

3.739

0.598

754

32.5

5.046

0.820

754

32.0

6.299

1.031

' 754

31.8

8.792

1.474

754

31.0

11.409

1.970

(Series

754

30.1

10.090
12.902
15.631
19.043
22.950
25.320
28.697
31.242

1.68
2.23
2.77
3.70
4.56
5.28
6.17
6.82

743. 'i mm.

743.7

743.7

743.4

743.4

743.4

743.4

743.4

31.5
30.4
29.6
27.0
25.8
25.2
24.4
24.1

*The results in Series 3 are those of Mr. G. M. Wilcox. In Series 4 a ther-
mometer graduated to tenths, which readily permitted the hundredths to be
estimated with the aid of a lens, was used, the temperature range being greater
than that of the Beckmann's thermometer.

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION.

321

Table 13.1

Potassium Chloride (KC1) Mol. Wt. 74.59.

(Series 1.)

Am't KC1 in

Rise of the Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

2.1223

0.293

737.6 mm.

41.9

5.1243

0.700

737.6

42.3

9.0126

1.247

737.6

41.8

13.9904

2.004

737.6

40.4

20.1703

2.975

737.6

39.2

24.1601

3.653

737.6

38.2

27.7204

4.266

737.6

37.7

31.8402

5.009

(Series 2.)

737.6

36.8

1.9117

0.255

744.0 mm.

43.3

4.0524

0.554

744.0

42.3

7.2257

0.986

744.0

42.4

11.6205

1.625

743.9

41.3

16.5203

2.406

744.0

39.4

21.3504

3.206

744.0

39.5

26.1305

3.911

744.2

38.5

30.3701

4.756

(Series 3.)

744.1

37.1

5.676

0.65

736.1 mm.

45.4

7.427

0.91

736.1

42.4

10.001

1.25

736.1

41.6

12.447

1.59

736.2

40.7

15.949

2.05

736.2

40.5

19.676

2.60

736.2

39.6

23.937

3.18

736.2

39.1

27.174

3.75

736.3

37.7

30.868

4.30

736.3

37.3

34.901

5.00

736.3

36.2

38.491

5.60

736.2

35.7

42.268

6.28

736.2

35.0

45.862

6.88

736.2

34.7

48.935

7.60

736.2

34.2

*In Series 3 the thermometer graduated to tenths was used.

322

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Table 14.

Potassium Bromide (KBr) Mol. Wt. 119.1.

(Series 1.)

Am't KBr in

Rise of the

Barometric

Molecular

LOO g. Water.

Boiling-point.

Pressure.

Weight.

2.6145

0.206

740.2 mm.

66.1

5.5045

0.433

740.2

66.1

9.5939

0.763

740.2

65.4

16.5033

1.351

740.2

63.7

23.3933

1.968

740.2

61.8

28.1778

2.413

740.2

60.7

33.2787

2.899

740.2

59.7

38.4978

3.425

740.2

58.4

43.4181

3.932

740.2

57.4

47.0656

4.312

740.2

56.8

51.2044

4.778

740.2

55.7

(Series 2.)

3.3803

0.244

739.5 mm.

72.0

5.6569

0.449

739.5

65.5

9.4227

0.725

739.5

67.6

13.4884

1.066

739.5

65.8

17.9788

1.437

739.5

65.0

22.3104

1.854

739.5

62.6

26.4854

2.249

739.5

61.2

30.4400

2.677

739.5

59.1

34.7605

3.115

739.5

58.0

39.7854

3.656

739.5

56.6

45.3672

4.267

739.5

55.3

49.0660

4.735

739.5

53.9

KAHLENBERG — TIIEORY OP ELECTROLYTIC DISSOCIATION. 323

Table 15.

Potassium Iodide (KI) Mol. Wt. 166.

(Series 1.)

Am't KI in

Rise of the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight

2.8034

0.155

736.1mm.

94.0

7.0320

0.397

736.1

92.1

10.8010

0.620

736.1

90.6

14.9234

0.870

736.1

89.2

19.7824

1.184

736.1

86.9

24.5374

1.494

736.0

85.4

29.2440

1.812

736.0

83.9

33.6664

2.134

736.0

82.0

39.0590

2.511

736.0

80.9

47.6110

3.159

(Series 2.1)

736.0

78.4

4.1747

0.23

740.6 mm.

94.3

6.1779

0.33

740.4

97.3

12.9296

0.72

740.4

93.3

19.0241

1.10

740.4

89.8

26.2379

1.58

740.0

86.4

35.0032

2.14

740.0

85.0

43.0591

2.74

739.4

81.6

66.2534

4.67

739.4

73.4

77.1725

5.55

739.5

72.1

85.7187

6.36

739.5

70.0

92.7357

7.02

739.5

68.6

104.8054

8.02

739.5

67.9

lThe thermometer graduated to tenths was used in this series.

324

BULLETIN OF THE UNIVERSITY OP WISCONSIN

Table 16.

Magnesium Chloride (MgCl2) Mol. Wt. 95.26.

Am't MgCL, in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

3.3713

0.416

750.1mm.

42.1

6.1999

0.850

750.0

37.9

9.1560

1.351

749.0

35.2

13.8696

2.380

750.0

30.3

16.8024

3.164

749.8

27.6

20.4226

4.243

749.8

25.0

22.0560

4.720

749.6

24.3

Table 17.

Barium Chloride (BaCL) Mol. Wt. 208.3.

(Series 1.)

Am't BaCl3 in

Rise of

the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

4.0785

0.242

742.8 mm.

89.7

8.7778

0.525

742.8

86.9

13.4221

0.825

742.8

84.7

18.6191

1.174

742.9

82.5

22.0768

1.586

742.9

78.9

32.0760

2.243

742.9

74.2

40.4680

2.970

742.9

70.9

47.8792

3.625

742.9

68.7

54.5198

4.157

742.9

68.2

(Series 2.)

3.3971

0.208

752.8 mm.

84.9

8.2907

0.496

752.8

86.6

13.6126

0.839

752.8

84.4

19.8682

1.293

725.8

79.9

27.0710

1.909

752.8

75.5

35.0366

2.517

752.8

72.4

38.8437

2.877

752.8

70.2

44.2550

3.362

752.8

68.5

48.1307

3.737

752.8

67.0

53.8634

4.157

752.8

67.3

KAHLENBERG — THEORY OE ELECTROLYTIC DISSOCIATION.

325

Table 18.

Mercuric Chloride (HgCla) Mol. Wt. 270.9.

Am't HgCl2 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

3.3416

0.056

751 mm.

310.1

8.5806

0.143

751

312.0

15.4630

0.248

750.9

324.2

24.8581

0.376

750.9

343.8

34.9070

0.496

750.8

366.4

45.8779

0.600

750.6

397.6

52.5994

0.645

750.5

423.1

Table 19.i

Potassium Chlorate (KCI03) Mol. Wt. 122.6.

Am't KCI03 in

Rise of the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

3.7431

0.34

738.8 mm.

57.2

8.1214

0.65

738.8

66.4

12.8379

1.01

738.6

66.0

17.1163

1.31

738.6

67.9

23.4841

1.72

738.4

70.9

29.6893

2.10

738.4

76.7

35.4205

2.49

738.1

73.9

42.9627

2.98

738.1

74.9

48.9283

3.43

737.6

74.1

iThis series of determinations was made with the thermometer graduated to
tenths.

326

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table 20.

Potassium Nitrate (KN03) Mol. Wt. 101.2.

(Series J.)

Am't KN03 in

Rise of the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

2.7896

0.248

741.1 mm.

58.5

6.0580

0.518

741.1

60.8

9.7271

0.822

741.1

61.5

14.7986

1.207

741.1

63.8

21.3338

1.706

741.2

65.0

27.0956

2.123

741.2

66.4

33.8032

2.577

741.2

68.2

41.5423

3.079

741.2

70.2

49.4270

3.570

741.3

72.0

57.2081

4.027

741.4

73.9

62.8302

4.357

(Series 2.)

741.4

75.0

4.2864

0.378

744.5 mm.

59.1

8.4346

0.725

744.6

60.5

13.0686

1.101

744.6

61.7

19.7400

1.603

744.6

64.0

28.0569

2.212

744.6

66.0

35.5446

2.710

744.8

68.2

44.5312

3.275

744.9

70.7

53.3702

3.795

744.9

73.1

61.6405

4.309

744.9

74.4

70.7683

4.677

744.9

78.7

KAHLENBERG — THEORY OP ELECTROLYTIC DISSOCIATION. 327

Table 21.

Silver Nitrate (AgN03) Mol. Wt. 170.0.

(Series 1.)

Am't AgN03 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

3.8939

0.197

739.4 mm.

102.8

11.9266

0.570

739.4

106.3

23.3420

1.066

739.4

113.9

35.0895

1.523

739.4

119.8

45.8973

1.915

739.4

124.6

56.3032

2.249

739.4

129.9

68.6870

2.636

739.4

135.5

83.3849

3.047

739.4

142.3

99.7473

3.521

739.4

147.3

110.2273

3.755

739.4

152.6

122.3325

4.060

739.4

156.7

136.2615

4.398

(Series 2.)

739.4

161.1

8.3155

0.422

738.8 mm.

102.4

16.2894

0.772

738.7

109.7

25.1374

1.091

738.7

119.8

30.6129

1.526

738.7

131.3

45.3921

1.887

738.7

125.4

54.3253

2.178

738.7

135.9

65.4093

2.516

738.7

135.2

74.5296

2.790

738.7

138.9

86.4310

3.143

73B.5

143.0

99.7190

3.496

738.4

148.3

115.2352

3.900

738.4

153.7

136.4676

4.431

738.4

160.2

328

BULLETIN OF THE UNIVERSITY OF WISCONSIN

Table 22.

Magnesium Sulphate (MgSOJ

Mol. Wt. 120.4.

Am't MgS04 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

2.7333

0.097

739.3 mm.

146.5

7.2368

0.281

739.3

168.6

27.5802

0.524

739.3

273.7

36.9100

0.925

739.3

207.5

43.4772

1.455

739.3

155.4

52.7743

1.984

739.3

138.3

60.5241

3.220

739.3

97.7

64.3938

3.316

739.4

101.0

72.2893

3.630

739.4

105.9

Table 23.

•

Zinc

Sulphate i

[ZnSOJ

Mol. Wt. 161.5.

Am't ZnS<34 in

Rise of

the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

2.8860

0.080

743.0 mm.

187.6

6.6472

0.169

743.0

204.5

10.1392

0.266

743.0

198.2

13.3894

0.372

743.0

201.1

17.7137

0.461

743.0

199.8

22.2021

0.591

743. 0

190.5

25.1993

0.690

743.0

189.9

28.2497

0.811

743.0

181.1

30.4712

0.890

742.0

176.3

32.8944

0.995

742.0

171.9

35.1802

1.122

742.0

163.0

37.3689

1.240

742.0

156.7

39.8343

1.381

742.0

150.0

41.3019

1.459

742.0

147.2

44.5661

1.671

742.0

138.7

KAHLENBERQ — THEORY OF ELECTROLYTIC DISSOCIATION.

329

Table 24.

Manganous Sulphate (MnSOJ Mol. Wt. 151.1.

Lm't MnSO, in

Rise of the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

3.7134

0.114

739 mm.

169.4

7.1327

0.193

739

192.2

10.2505

0.282

739

194.1

14.4644

0.373

739

201.7

19.3404

0.520

739

193.5

24.2095

0.678

739

185.7

Table 25.

Cadmium Sulphate (CdSOJ Mol. Wt. 208.1.

Am't CdS04 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

4.5635

0.105

741.3 mm.

225.8

10.9721

0.215

741.3

265.4

15.0901

0.287

741.3

273.5

20.6623

0.356

741.3

301.7

24.7605

0.385

741.3

334.4

27.7718

0.494

741.3

292.3

32.9341

0.604

741.3

283.5

36.7641

0.699

741.3

273.4

41.2807

0.820

741.3

261.8

47.3809

0.988

741.3

249.3

53.4751

1.164

741.3

239.4

330

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Table 26.
Nickelous Sulphate (NiSOJ Mol. Wt. 154.8.

Am't NiS04 in
100 g. Water.

2.7661

5.2551

7.6761

11.1964

15.1358

17.9435

20.8475

23.1431

25.5253

27.1590

29.0219

31.1444

32.7051

34.4614

35.1654

37.7353

Rise of the
Boiling-point.

0.096

0.169

0.230

0.336

0.448

0.536

0.641

0.738

0.841

0.939

1.042

1.190

1.302

1.489

1.576

1.734

Barometric
Pressure.

737 mm.

737

737

737

737

737

737

737

737

737

737

737

737

737

737

737

Molecular
Weight.

149.8

161.7

173.5

173.3

175.7

174.1

169.1

163.1

157.8

150.4

144.8

136.1

130.6

120.0

118.7

113.2

i

Table 27.

Cobaltous Sulphate (CoSOJ Mol. '

Wt. 155.1.

Am't CoS04

in

Rise of

the

Barometric

Molecular

100 g. Water.

Boiling-point.

Pressure.

Weight.

2.1070

0.068

736

mm.

160.8

4.4465

0.110

736

205.3

8.7442

0.201

736

226.1

9.5963

0.262

736

190.5

12.9365

0.346

736

194.3

16.1345

0.449

736

186.3

20.6000

0.568

736

188.6

22.1513

0.626

736

184.0

24.0703

0.694

736

180.8

26.1501

0.772

736

175.7

28.7453

0.876

736

170.8

32.8415

1.055

736

161.9

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 331

Table 28.

Ferrous Sulphate

(FeSOJ

Mol. Wt. 152.1.

Am't FeSO, in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight

3.2451

0.093

738 mm.

181.4

6.7048

0.182

738

191.6

9.2220

0.243

738

197.3

13.0874

0.343

738

198.4

15.8107

0.412

738

199.5

17.9628

0.483

738

193.4

22.8063

0.545

738

212.6

24.4524

0.633

73S

200.9

26.6450

0.713

738

194.3

28.7886

0.805

738

185.6

30.6928

0.899

738

181.7

32.7685

0.994

738

171.4

35.3460

1.099

738

167.2

Table 29.

•

Cupric Sulphate

(CuSOJ

Mol. Wt. 159.7.

Am't CuS04 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

3.3569

0.091

742.9 mm.

191.8

7.8116

0.189

742.7

214.9

12.2085

0.186

742.7

221.5

15.9522

0.374

742.6

221.8

22.9147

0.571

742.6

208.7

27.4664

0.708

742.5

201.8

32.3565

0.874

742.5

192.5

36.4495

1.042

742.4

181.9

39.5708

1.192

*742.2

172.6

44.0370

1.414

742.2

158.4

48.6314

1.692

741.9

149.5

52.0243

1.916

741.8

140.9

56.9514

2.283

741.7

129.7

64.1409

2.903

741.7

114.9

68.9859

3.363

741.7

106.7

73.7718

3.768

741.7

101.8

332 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

In table 12 giving the results for ISFaCl it appears that the
molecular weight decreases steadily with the increase of con-
centration1, becoming in the strong solutions less than half the
theoretical molecular weight. The facts then indicate that the
dissociation of common salt would increase with the con-
centration and that in solutions above about 20 per cent, the
molecule would break up into more than two parts, which is
impossible on the basis of the atomic theory as generally ac-
cepted. The behavior of !NaCl is clearly diametrically op-
posed to that which we should expect according to the theory of
electrolytic dissociation. The electrical conductivity of E"aCl
solutions increases regularly with the dilution, as table 2 shows.
From the character of the boiling-point results it is clearly out-
of the question to make even an attempt to compare the dis-
sociation as calculated from the molecular weight determina-
tions with the dissociation as deduced from the electrical con-
ductivity measurements.

What has been said concerning NaCl applies also to KC1
(Table 13), KBr (Table 14) and KI (Table 15.) The molec-
ular weights of these salts continually diminish with increase
of concentration, finally becoming less than half the theoretical,
whereas the conductivities increase regularly with the dilu-
tion (Table 2). It is interesting to note the similarity of the
behavior of the haloid salts of the alkalies, to which attention
has been previously directed in a general way.

The molecular weight of MgCL, too, decreases with the in-
crease of the concentration (Table 16), finally becoming less
than one-third the theoretical value. This salt would then
have to dissociate into more than three ions, and that in con-
centrated solutions. On the other hand the conductivity in-
creases with the dilution. It is again clearly useless to at-
tempt a comparison of the degree of dissociation as computed
from the observed molecular weights and the conductivity.

What has been stated concerning MgCl2 applies exactly to
BaCl2 (Table 17), so that further comments about the behavior

»-The same fact is also demonstrated by the determinations of Landsberger
and Biltz — Zeit. anorg. Chem. 17, 452 (1898).

KAHLENBERG — TIIEORY OP ELECTROLYTIC DISSOCIATION. 333

of the latter salt are superfluous. It is interesting to note that
these two salts of analogous composition exhibit a similar be-
havior, which resembles closely that of the haloid salts of the
alkalies.

Mercuric Chloride (Table 18) shows no dissociation by the
boiling-point method. The behavior of mercuric chloride dif-
fers from that of the salts last mentioned in that its molecular
weight increases with the concentration. Of course with this
behavior polymerization of the molecules with increase of con-
centration could consistently be assumed; it could further be
assumed that some of the molecules not yet polymerized are
electrolytically dissociated, and thus the observed phenomena
could with these assumptions be brought into harmony with
existing conceptions, at least qualitatively. The electrical con-
ductivity of the solutions of this salt (Table 2) though rela-
tively low, increases regularly with the dilution.

The boiling-point determinations for KC103 (Table 19)
were made with a thermoneter graduated to tenths, so that the
measurements are relatively less accurate than those in which
the Beckmann thermometer was used. The results are suf-
ficient to indicate, however, that in the case of this salt the
molecular weight increases with the concentration, which is
at least qualitatively in harmony with that which the dissocia-
ion hypothesis requires. The degree of dissociation correspond-
ing to a molecular weight of 66 is 86 per cent., whereas for
the same strength of solution the conductivity results (Table
2) indicate a dissociation of not more than 70 per cent. No
special stress is laid upon this comparison, however, because
the Beckmann instrument was not employed in making the de-
terminations.

In the case of KN03 (Table 20) we again have an increase
of molecular weight with increase of concentration, which agrees
qualitatively with the requirements of the dissociation theory.
For the most dilute solution tested the molecular weight is 58.5,
which corresponds to 73 per cent, dissociation; from the con-
ductivity results (Table 2) the dissociation for this concentra-
tion is about 72 per cent., — a satisfactory agreement. For a

334 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

normal solution the molecular weight is about 61.7 correspond-
ing to 64 per cent, dissociation; the conductivity results yield 56
per cent. Silver nitrate (Table 21) also shows an increase
of molecular weight with increase of concentration, which
agrees qualitatively with the dissociation theory. The most
dilute solution tested yielded a molecular weight of 102.8,
corresponding to a dissociation of 65 per cent. ; the conduc-
tivity results yield about 67 per cent., — an acceptable agree-
ment. For a normal solution the molecular weight is about
110 corresponding to 54 per cent, dissociation; the conductivity
determinations indicate 52 per cent., — again a very fair agree-
ment. It happens, then, that the behavior of potassium and
silver nitrates agrees much better with the demands of the dis-
sociation theory at the boiling-point of the solutions than at
the freezing-point1. It will be noted that these nitrates behave
alike, and that solutions of KC103 apparently exhibit a be-
havior similar to that of the nitrates.

The sulphates (Tables 22 to 29) again show great similarity
in their general behavior. In the case of MgS04 (Table 22)
the molecular weight begins with a value somewhat above the
theoretical, — which indicates no dissociation; then it increases
at first with the concentration and finally it decreases with in-
crease of concentration after having passed through a maximum,
the values in the strongest solutions becoming less than the
theoretical. There is clearly no irregularity in the conduc-
tivity values (Table 2) to even suggest such a behavior. What
has been said about MgS04 applies also to ZnS04 (Table 23),
NiS04 (Table 26) and CuS04 (Table 29). The same general
behavior is also exhibited by MnS04 (Table 24), CdS04 (Table
25), CoS04 (Table 27) and FeS04 (Table 28), except that
the molecular weights of these salts, while first increasing, and
then decreasing, with the increase of concentration, always
remain above the theoretical values. As table 2 shows, there
is nothing in the conductivity results to lead one to expect
such a behavior. A comparison of the freezing-point results
(Tables 4 to 10) with those obtained by the boiling-point method

1 Compare for Instance Arrhenius' table 1. c.

KAHLEXBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 335

(Tables 22 to 29) shows that the molecular weight of the sul-
phates is less by the former than by the latter method in the
case of corresponding concentrations. So that if it be assumed
that these sulphate- are polymerized in their solutions, it fol-
lows that this polymerization is greater at the boiling-points
of the solutions than at their freezing-points, which seems un-
likely.

It was thought to be of interest in this connection to in-
vestigate the behavior of a non-electrolyte. Cane sugar was se-
lected, the results obtained with which by the boiling-point
method are given in table 30. The results indicate clearly that
the molecular weight diminishes appreciably as the concentra-
tion increases. Strong sugar solutions, however, do not — as is
well known — conduct electricity in consequence thereof. The
solution was finally tested with Folding's solution to see whether
any sugar had become inverted during the process of boiling,
but no invert sugar was found. On the other hand a series
of boiling-point determinations of solutions of H3BO, (Table
31) shows that the molecular weight remains practically con-
stant for very considerable changes in the concentration of this
substance, considering its low molecular weight. The freezing-
point of solutions of H3BO31 show that the molecular weight
is lower at 0° than at 100° ; and its solutions at the lower tem-
perature really ought to be somewhat better conductors of elec-
tricity (according to the dissociation hypothesis) than they are.

1 Compare Kahlenberg und Schreiner, Zeit. phys. Chem. 20, 548 (1896).

336 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

Table 30.

Cane Sugar, (C18 H28 ■011) Mol. Wt. 342.

Am'tC13H,, On in
100 g. Water.

20.757
29.518
36.155
42.692
49.389
57.354
65.978
77.777
92.972
103.426
113.402
114.900
125.159
137.830
149.131
159.987
167.550
175.161
187.185
197.736
207.189
222.082
236.989
248.090
259.191
266.733
276.223
289.455

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular

Weight.

0.30

736.6 mm.

360

0.42

736.6

366

0.55

736.6

342

0.70

736.6

310

0.75

736.6

335

0.91

736.6

328

1.13

736.6

304

1.41

736.6

280

1.77

737.1

273

2.06

737.4

261

2.20

737.6

268

2.32

737.6

258

2.57

737.6

253

2.90

737.6

247

3.20

737.6

242

3.48

737.6

239

3.70

737.6

236

3.84

737.9

237

4.25

737.9

229

4.56

738.5

226

4.80

738.5

225

5.20

739.0

222

5.60

739.0

220

5.92

739.0

218

6.11

739.0

221

6.41

739.0

216

6.71

739.1

214

7.10

739.0

212

KAIILENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 337

Table 31.i

Boric Acid

(H3BO3) Mol. Wt. 62.

Im't H3BO3 in
100 g. Water.

Rise of the
Boiling-point.

Barometric
Pressure.

Molecular
Weight.

3.161

0.26

743 mm.

63.2

5.264

0.42

743

65.2

S.746

0.72

743

63.0

12.040

1.01

743

62.2

14.098

1.18

743

62.1

16.600

1.41

743

61.2

19.956

1.67

743

62.1

23.896

2.00

743

62.1

26.500

2.13

742.5

64.5

29.295

2.41

742.5

63.2

33.793

2.82

742.5

62.3

36.407

3.01

742.5

62.9

Discussion.

The difficulties which the theory of electrolytic dissociation
encounters in explaining the phenomena in aqueous solutions
are really insurmountable. We have seen that there are solu-
tions which are excellent electrical conductors, and yet the molec-
ular weight determinations show a normal molecular weight
of the dissolved substance. It is clear that while in some cases
the molecular weight increases with the concentration, thus ac-
cording at least qualitatively with the theory, in other cases the
molecular weight decreases with the increase of the concentra-
tion, finally becoming less than what it ought to be even on the
assumption that electrolytic dissociation is complete. Again, in
other cases the molecular weight at first increases with the
concentration and then it diminishes as the concentration in-
creases. And these phenomena are observed in solutions the
conductivity of which steadily increases with the increase of
the dilution. I have not given any examples of aqueous solu-
tions in which the molecular conductivity does not increase

^In this series, which was really only a preliminary one, the thermometer grad-
uated to tenths was used.

338 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

regularly with the dilution; but such cases do exist. So, for
instance, the molecular conductivity of aqueous solutions of the
alkaline hydroxides first increases with the dilution and then
decreases as the dilution increases1.

Prom the facts here presented in the case of aqueous solutions
and those detailed above in the case of non-aqueous solutions,
it follows that there is no such connection between the freezing-
points and boiling-points of solutions on the one hand and their
electrical conductivity on the other, as is claimed by the theory
of electrolytic dissociation of Arrhenius. In numerous cases
not even a qualitative agreement exists. A careful scrutiny of
Arrhenius' original table reveals the fact that while in a certain
number of instances the agreement of the values of the factor
i, as computed from cryoscopic measurements and from con-
ductivity determinations, is acceptable, in many cases it is
poor, and again in others it is entirely wanting. To be sure,
Arrhenius bases this table upon measurements which he deemed
might in some cases contain large errors; but later experi-
mental work has really only served to emphasize the presence
of such discrepancies. Further we have seen that investiga-
tions of non-aqueous and of aqueous solutions have in reality
yielded a host of facts which even the most ardent adherents
of the dissociation theory have not been able to harmonize with
it. For some facts, to be sure, explanations have been offered
upon the basis of auxiliary assumptions which frequently had
no root in facts, having been created simply to save the dis-
sociation theory from being pronounced untenable.

The attempt has been made to explain all of the various
properties of electrolytic solutions upon the basis of the theory
of electrolytic dissociation. To these efforts attention must
now be directed. The various additive properties of salt solu-
tions as mentioned by Arrhenius and as detailed by Ostwald
and by Nernst in their text-books, are presented as supporting
the dissociation theory. But it is clear that even if these ad-
ditive properties could be explained on the basis of the disso-

*The determinations of Kohlrausch show this phenomenon. See also the
measurements of Kahlenberg and Lincoln, Jour. Phys. Cheni. 2, 87 (1S98).

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 339

ciation theory, the theory could not be based on this alone, since
additive properties are well known to exist in the case of true
chemical compounds, where, since there are no solutions under
consideration and since there is no electrical conductivity ob-
servable, the possibility of electrolytic dissociation is entirely
out of the question. In the realm of physiology, where it at
first seemed that the theory of electrolytic dissociation would be
particularly helpful, it has after all appeared that it can not
cope with the facts1.

The heats of neutralization of acids and bases in dilute solu-
tions have been heralded as an argument in favor of the disso-
ciation theory; but C romp ton2 has shown that the dissociation
hypothesis is not only unnecessary to explain the heats of neu-
tralization, but that it is really inadequate, for it does not
bring the behavior of electrolytes, as far as heat changes that
accompany the formation of salts in aqueous solution are con-
cerned, into line with the behavior of non-electrolytes. It is
unnecessary to dwell further upon the insurmountable difficul-
ties which the dissociation theory meets in general in the realm
of thermal chemistry. These difficulties have been sufficiently

1In this connection the reader is referred in particular to the following ar-
ticles and to the additional references that they in turn contain: L. Kahlen-
berg, The Taste of Acid Salts and Their Degree of Dissociation, Jour. Phys.
Chem. 4, 33 (1900). T. W. Richards, The Relation Between the Taste of Acids
and Their Degree of Dissociation, Ibid. 4, 207 (1900). L. Kahlenberg, The Taste
of Acid Salts and Their Degree of Dissociation II, Ibid. 4, 533 (1900). J. F. Clark,
Electrolytic Dissociation and Toxic Action, Ibid. 3, 263 (1899). L. Kahlenberg
and R. M. Austin, Toxic Action' of Acid Sodium Salts on Lupinus Albus, Ibid. 4,
553 (1900).

In reviewing the above articles for the Jour. Amer. Chem. Soc. and the Zeit.
phys. Chem., Arthur A. Noyes has made the attempt to bring the facts into
harmony with the dissociation theory. I will simply state here that I have no
desire whatever to enter upon a discussion of these "explanations" of Mr.
Noyes, the weakness of which is sufficiently apparent upon the face of them.
The facts are before the reader and he can safely be left to judge for himself.
I must request the reader, however, to refer to the original of the third article
in the above list, or at any rate to use the review of it given in the Chemisches
Centralblatt or the Jour. Chem. Soc. (London), since Noyes has omitted to men-
tion an essential part of the very simple experiment upon which the argument
is based, and has then claimed that the experiment is irrelevant. Evidently Mr.
Noyes in his ardor to uphold the dissociation theory did not see the full import
of the experiment in question.

*Jour. Chem. Soc. (London) 71, 951 (1S97). See also Crompton's interesting ar-
ticle on Rotations of Optically Active Salts, Ibid. p. 946.

340 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

discussed by Reychler1, whose conclusion is that, "above every-
thing else we notice that the hypothesis of free ions is in op-
position to thermo-chemical observations"2.

The attempts to harmonize the theory of electrolytic dissocia-
tion with the law of mass action have signally failed in the
case of the electrolytes par excellence,, as is well known, in spite
of the fact that very earnest endeavors have been made in this
direction for over a decade. In the case of weak organic acids,
to be sure, a tolerable agreement between the law of mass
action and the dissociation theory has been found by Ostwald.
The fact that the dissociation hypothesis cannot be brought into
harmony with the law of mass action is one of the strongest
arguments against the theory. It is really unfortunate that
in discussing problems of equilibrium into which strong elec-
trolytes enter (their solubility for instance) the adherents of
the dissociation theory should go right ahead with their mathe-
matical equations and deductions as though the theory were in
full accord with the law of mass action3.

The chemical reactiveness of electrolytes has been explained
by attempting to ascribe to the ions a peculiarly strong chemical
activity on account of the electrical charges that are supposed
to reside upon them.4 The fact that a goodly number of sub-
stances will not react with each other when water is not present
and that they do react in aqueous solution, or at any rate
when moist, has been called into requisition in this connection.
While this behavior may be claimed to agree with the disso-
ciation theory, it cannot be used as an argument to support the
latter; for it is clear that many pure substances and mixtures

1 Outlines of Physical Chemistry. (Translated by McCrae.) Whittaker and Co.
(1899), page 214.

2 The italics are Keychler's.

9 Compare for instance the general and unqualified statements concerning the
so-called solubility product contained in Ostwald's "Scientific Foundations of
Analytical Chemistry," which the author applies to electrolytes, to most of which,
certainly, it does not apply unqualifiedly.

*A recent statement of H. C. Jones illustrates the extreme views that are en-
tertained by some regarding this matter. He concludes a review of the work
done on the dissociating power of solvents (Amer. Chem. Jour. 25, 232 (1901) ) with
the statement, "The chemistry of atoms and molecules has thus given place
to the chemistry of ions".

KAHLENBEBG — THEORY OF ELECTROLYTIC DI8S0CIATION. 341

in which there are no grounds whatever for assuming the
presence of ions, are nevertheless exceedingly reactive chem-
ically,— take for instance, many well known explosives as a
striking example. And on the other hand it is a well recognized
fact that, in many cases at least, salts, acids and bases unite
chemically with water and other solvents, and that any re-
action which then takes place in solution is one between these
new products, and that therefore such reactions might easily
occur in presence of water, whereas the anhydrous substances
might not react at all. It might be helpful to some to use the lan-
guage of the dissociation theory and to say, for example, — the
analytical test for chlorine ions is silver ions; instead of saying,
— the analytical test for chlorine in the form of a soluble chlor-
ide is silver nitrate or any other soluble silver salt in which silver
is the base ; but that the new terminology, coupled with an at-
tempt to apply the law of mass action to electrolytes in a way
in which it certainly does not apply, forms a scientific founda-
tion for analytical chemistry, is a position that is clearly un-
tenable. The very fact that analytical chemistry has not
received much benefit from Professor Ostwald's little book on
"The Scientific Foundations of Analytical Chemistry," in the
way of improving existing analytical methods and discovering
new ones, speaks for itself.

In connection with the dissociation hypothesis the solvent has
been considered as having a peculiar "dissociating power".
Water, then, yielding such excellent conducting solutions as it
does, would have a very high degree of this dissociating power.
The effort has been made by Nernst and by J. J. Thomson, prac-
tically simultaneously, to ascribe this strong dissociating power
of water to its high dielectric constant, which is about 80 at
room temperatures. At the time when this was done, relatively
few solvents had been investigated that yielded solutions having
considerable conductivity, and so it was perfectly easy to show
that in the case of water, formic acid, alcohol, ether and benzol,
for example, the conductivity of the solutions in which these
liquids are the solvents diminishes with the dielectric constant

342 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

of the solvent.1 The idea underlying the attempt to bring this
hypothetical dissociating power into correlation with the dielec-
tric constant of the solvent, is that a high dielectric constant of
the latter would make it more difficult for the electrically
charged ions to neutralize their charges by reason of the electro-
static attraction existing between them. It is not claimed that
high dissociating power is proportional to the specific inductive
capacity of the solvent, but simply that it increases and dimin-
ishes with it, the exact mathematical relation being as yet un-
known. Since the j^ernst-Thomson rule has been put forth the
electrical conductivity of various salts in a goodly number of
solvents has been investigated. 2 While the dielectric constants
of all the solvents tested were not known at the time, so that a
comparison could be made in all cases, in the majority of in-
stances where the dielectric constants were known, the Nernst-
Thomson rule was indeed corroborated.2 At the same time a
few striking exceptions were present. The relatively low dielec-
tric constant of liquid ammonia3 and the high conductivity14 of
solutions of salts in it, speak powerfully against the Kernst-
Thomson rule. It can hardly be argued that this high conduc-
tivity in liquid ammonia is due largely to the high rate with
which the ions move, because the conductivity of the solutions
has been examined at the boiling-point of the solvent, — 38° ;
for liquid ammonia has a specific inductive capacity lower than
that of alcohol, and yet alcoholic solutions at their boiling-point
have incomparably lower electrical conductivity than that ob-
served in liquid ammonia solutions. Another striking excep-
tion to the Xernst-Thomson rule has recently been pointed out
by H. Schlundt,5 who found the dielectric constants of butyro-
nitrile and pyridine to be 20.3 and 12.4, respectively, and
pointed out that nevertheless the solutions in the latter solvent

1 Compare for instance Nernst's table on page 365 of the 3d edition of his book,
Theoretische Chemie, F. Enke, Stuttgart (1900).

2 Compare Kahlenberg and Lincoln, 1. c, also Lincoln, 1. c, and the additional
articles referred to in these papers*

3 Goodwin and Thompson, Physical Review 8, 38 (1S99).
* Franklin and Kraus, 1. c.

"Jour. Phys. Chem. 5, 157 (1901).

KAHLENBERG — THEORY OF ELECTROLYTIC DISSOCIATION. 343

are known to be the Letter conductors. Again liquid S02,
which Walden1 has shown to yield excellent conducting solu-
tions, has a low dielectric constant2 that would not lead one to
expect such a behavior. The dielectric constant of liquid HCIST
was found by Schlundt3 to be 95 ; this would lead one to expect
this solvent to have a dissociating power greater than that of
water. Preliminary tests which Mr. Schlundt and I have made
show that solutions in liquid HCN are very much poorer con-
ductors of electricity than corresponding aqueous solutions.4
On the other hand I have found that amyl amine with a specific
inductive capacity of the order of that of chloroform5 yields
fairly good conducting solutions. More striking proofs that
the ISTemst-Thomson rule is untenable could hardly be pro-
duced.6 The fact that the Nernst-Thomson rule can not be
maintained takes away another pillar upon which the dissocia-
tion theory has been resting.

That the "dissociating power" of solvents is dependent upon
the polymerization of their molecules, as claimed by Dutoit and
Aston, is not in harmony with the facts in many cases, has
clearly been shown by Kahlenberg and Lincoln.7 Again it has
been maintained by Briihl8 that "dissociating power" is pos-

*]. e.

2 The exact value has been determined in this laboratory by Mr. Schlundt who
will report upon the same in connection with numerous measurements made on
other solvents, among which are practically all the solvents investigated by
Walden, 1. c. Some older determinations of the dielectric constant of S02 have
been found in the literature by Mr. Schlundt, which he will present in connec-
tion with his own work.

*1. c.

*We hope soon to be able to publish exact conductivity measurements of solu-
tions in liquid HCN and also of solutions in liquid cyanogen.

6 The exact value of the dielectric constant of amyl amine will be reported by
Mr. Schlundt, whose list of determinations includes a fairly complete series of
the substituted ammonias of both the fatty and aromatic series.

•Nernst himself (Theoretische Chemie, 3d Edition, p. 365) has realized the dif-
ficulty of harmonizing his rule with the far less striking instance that NaCl,
KBr, etc., in formic acid (dielectric constant 62) solutions conduct almost as well
as the corresponding aqueous solutions, in which connection he remarks that
other "specific influences" come into play. He states, "Wahrscheinlich steht
hier in erster Linie eine Association der Ionen mit Molekiilen des Losungsmit-
tels". It is interesting to compare in this connection the treatment which the
hydrate theory receives at the hands of the same writer, page 491.

n. c

8Zeit. phys. Chem. 18, 514 (1895). Ibid. 27, 317 (1898). Berichte deut. chem. Ges.
30, 163 (1897).

344 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

sessed by such solvents as are unsaturated in character. It has
been shown in this connection1 that Briihl's position is unten-
able, inasmuch as some solvents, which according to Briihl's view
are unsaturated, and of which Briihl had predicted that they
would yield conducting solutions, were found to yield solutions
of high resistance. Later Briihl2 has entered the objection that
he did not mean to assert that whenever a solvent possesses spare
valences it must necessarily yield conducting solutions. In
other words, he claims that he did not mean to assert the con-
verse of his original statement. Briihl cites in this connection
that the statement, that whenever a compound is optically active
it possesses an assymetric carbon atom, is also not necessarily
true when taken conversely. He apparently forgets, however,
that in our knowledge of racemic mixtures and meso compounds,
we have reasons why the converse of the latter statement is not
necessarily true. A corresponding reason why his own state-
ment should not hold in the converse has, however, not been
furnished by Briihl.

The theory of electrolytic dissociation is at present at its best
in explaining the phenomena of actual electrolysis. But it
must nevertheless be admitted that there are important phenom-
ena of electrolysis which the theory does not explain satisfactor-
ily. Thus if when, for example, a silver solution is electro-
lyzed, the process consists in each case of neutralizing the posi-
tive charge residing on silver ions (as far as the process at the
cathode is concerned), as the theory claims, why do we always
get poorly adhering crystalline deposits from certain solutions
and dense, well-adhering deposits from others, the potential and
the current density being the same ? The writer has also ob-
served certain phenomena which appear to him to be incom-
patible with the idea that during the process of electrolysis there
is a regular procession of charged, oriented, material particles
in the solution. The study along this line is being pursued
further and it is hoped that the results may be ready for pub-
lication at some date in the near future. The study of the

1Kahlenberg and Lincoln, 1. c.
2Zeit. phys. Cbem. 30, 1 (1899).

KAHLENBERQ — THEORY OF ELECTROLYTIC DISSOCIATION. 345

changes of concentration that take place around the electrodes
in the electrolysis of non-aqueons solutions promises to yield re-
sults of unusual interest, especially as bearing upon the value
of the dissociation theory in interpreting electrolytic phenomena.
Since the time when Hittorf1 determined the migration numbers
of Cdl2, Znl2 and ZnCL in absolute alcohol and those of Cdl2
in amvl alcohol, this field has not been cultivated. Now we
know of a number of fairly good and some cases of excellently
conducting non-aqueous solutions, in which the migration num-
bers await determination — work begun in this laboratory.

It might not be superfluous to recall in connection with the
claim that thermodynamics requires the dissociation theory, that
Clausius, who showed the discrepancy between the Grotthus the-
ory and thermodynamics, did not find it necessary to put forth
such a radical hypothesis as that of Arrhenius. Again, Hittorf
on the basis of his studies of the migration of the ions evidently
did not think it necessary to frame a theory giving the term ion
the meaning that it now has. Finally let the reader try to re-
call any real marked improvements or discoveries in the realm
of electrolysis which are directly traceable to the influence of the
dissociation theory. The function of E. M. F. in electrolysis,
especially in electrolytic separations, has been more strongly em-
phasized, but that is really about all. The importance of cur-
rent density was early pointed out by Bunsen, and as far as the
influence of the temperature of the electrolyte upon the mechan-
ical and chemical character of the deposit is concerned, we are
still upon an empirical basis as before. It is very significant,
for instance, that in the latest edition of his work on quantita-
tive analysis by electrolysis, Classen has devoted about four
pages of the introductory part of the book to the ionic theory,
and after that in the main body of the book we read nothing
more of that theory ; the preparation of the solutions from which
to get suitable deposits is very much upon the same empirical
basis as ever. And it is also safe to say that electrolysis as
used in the arts has not received much help from the theory of
Arrhenius.

»L c.

346 BULLETIN OF THE UNIVEKSITY OF WISCONSIN.

The dissociation theory has led to Nemst's theory of the
E. M. F. of galvanic cells, which has already been referred to
above. This theory is an attempt to explain the difference of
potential between two electrolytes and to account for the differ-
ence of potential between an electrode and an electrolyte, and
this not only qualitatively but also quantitatively. Nernst's
theory assumes that metals have a certain tendency to pass into
the ionic condition, which tendency is termed the electrolytic
solution tension of the metal. That which operates against this
tendency is supposed to be the osmotic pressure of the ions of
the metal already present in the solution, and the difference of
potential between the metal and the electrolyte is the result of
the action of these two forces ; on the other hand, the difference
of potential between two electrolytes is ascribed to the different
rates with which the charged ions move. Nernst's formula
really involves the assumption that the law of mass action is ap-
plicable to electrolytes in the sense required by the dissociation
theory. That the law of mass action does not hold, however, in
the case of electrolytes par excellence, has already been men-
tioned. By maintaining the correctness of Kernst's formula
and thus assuming that the law of mass action does hold for such
electrolytes, Jahn has arrived at the conclusion (as clearly he

must) that z^L does not correctly represent the degree of dis-

Aoo

sociation, and that the ionic velocities vary in dilute solutions.
The latter is not, in many cases at least, in harmony with the
facts. Arrhenius, on the other hand, stoutly defends his orig-
inal ul- which of course leads to a denial of the validity of
Aoo

the mass law as applied to the electrolytes in question. Ost-
wald, too, in the new edition of his Grundriss (p. 406) clearly

inclines toward maintaining the time honored — formula.

The polemical discussion between Arrhenius and Jahn is still go-
ing on in the Zeit. phys. Chem., and recently Nernst has also
taken a hand in the debate. It seems at first rather deplorable
that so much valuable energy is being expended in trying to de-

KAHLENBERG— THEORY OF ELECTROLYTIC DISSOCIATION. 347

cide which is the correct way to calculate the degree of dissocia-
tion, regarding which there are such excellent reasons to believe
that it has no counterpart in reality. Naturally then insur-
mountable obstacles must arise in determining the value. These
polemical discussions, however, are doing considerable good in
that they emphasize how inadequate the dissociation theory
really is, — they represent the beginning of the end of that the-
ory.

v

It is true that as soon as the theory of electrolytic dissociation
is declared invalid the original difficulty with the van't Hoff
theory of solutions1 recurs, namely, the theoretical interpreta-
tion of the factor i. Whenever the factor i in the equation
PV=«RT, is unity we have the gas equation in its simplicity
as it holds for dilute solutions of the now classical cane sugar.
When in any case i is less than unity and diminishes as the con-
centration increases, the assumption that polymerization of the
dissolved molecules takes place can be made; but when i is
greater than unity, dissociation must be assumed. Arrhenius
assumed so-called electrolytic dissociation; from which it fol-
lowed that whenever a solution conducts electrolytically it re-
quires a corresponding factor i greater than unity, — that this
is by no means always the case has been sufficiently set forth
above. Again it has been shown above that, in the case of cane
sugar, for instance, a factor i which increases with the concen-
tration must be introduced. There is no other logical theoretical
significance to put upon this behavior than to assume that the
stronger the sugar solution is the more the solute dissociates.
This conclusion is absurd, — let alone the additional fact that
sugar solutions do not conduct. And cane sugar is by no means
the only non-electrolyte that behaves thus. Attention has been
directed to the fact that Dieterici found that the molecular lower-
ing of the vapor tension of dextrose and urea also increases with
the concentration like that of cane sugar.

I am well aware that the gas equation is supposed to hold
strictly only for infinitely dilute solutions, just as it holds only

^Compare in this connection, Crompton's explanation, Jour. Cheni. Soc. Lon-
don 97, 925 (1897).
4

348 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

for ideal gases, and that the solutions with which Dieterici
worked varied between 0.1 and 1.0 normal, and that those
used in experiments detailed above frequently were much
stronger than normal. That a normal solution is nevertheless
for many of the practical purposes of life a rather dilute solu-
tion will hardly be disputed. ~No one expects the gas equation
to hold strictly for a normal solution or even for one consider-
ably more dilute ; but what one has a right to expect from the
modern theory of solutions is, that with increasing concentration
a solution should behave at least qualitatively as a gas does with
increase of pressure. And this requirement is clearly not met,
since while all gases behave alike under increase of pressure (so
that van der Waals has been able to express their behavior by
means of his well known equation) solutions, as has been shown,
often behave in a manner opposite to that of gases, and this,
too, frequently in solutions that can not be termed concentrated.
This demonstrates, then, that the van't Hoif law is at best only
approximate and must be applied with great care. As Dieterici
well says :

"Raoult hat seine Gesetze der Damfspannungs- und Gefrierpunkts-
depression durchaus nicht als absolut streng giiltige Naturgesetze
aufgestelit, sondern als nahezu zutreffende Erfahrungssatze, welche fur
die Zwecke der Molekulargewichtsbestimmung genau genug sind."

We have seen above (and the literature is replete with records
of facts illustrating the same point) that substances of similar
chemical composition, when dissolved in the same solvent, be-
have similarly, as far as the change of the boiling- or freezing-
points are concerned ; this clearly shows that the influence of the
chemical nature of the dissolved substance enters into the de-
termination of the molecular rise of the boiling-point and the
molecular lowering of the freezing-point.

In pressing the analogy between gases and solutions (which
undoubtedly exists and from which at times valuable sugges-
tions may be derived) it has often been forgotten that this is
after all simply an analogy; and like other analogies it fails
when carried too far. It is so easy to compare the process of
dissolving a lump of sugar in a beaker of water with the expan-

KAULENLERG — THEORY OF ELECTROLYTIC DISSOCIATION'. 349

sion of a gas, — the analogy is at once apparent. In seeing it
with the mind's eve one abstracts from the water and centers the
attention entirely on the sugar. But it must be remembered
that a gas will expand readily in vacuo, and that it will mix with
any other gas or mixture of gases, while on the other hand, the
lump of sugar will not dissolve when, for instance, benzene or
absolute alcohol is poured over it. The process of solution of
a substance and the expansion of a gas, then, while possessing
analogy, are in reality very different processes. And right here
lies the difficulty with the theory of solutions. It neglects the
all important role of the solvent. It fails to emphasize the fact
that the process of solution takes place because of a mutual at-
traction between solvent and dissolved substance, and that this
mutual attraction, which is a function of the chemical nature of
both solvent and dissolved substance, is the essence of the so-
called osmotic pressure.1 It is true that the thermodynamic
considerations of van't Horr will hold whether the osmotic pres-
sure be considered as the outcome of a mutual attraction of solv-
ent and dissolved substance, or as resulting from the bombard-
ment of the molecules of the dissolved substance against the
semipermeable membrane. But if we choose to use the gas equa-
tion in working with solutions it is very evident that the factor
i must never be placed equal to unity (unless direct experi-
mental evidence justifying this step is at hand) if exact results
are desired, no matter whether we work with electrolytes or non-
electrolytes. The dissociation theory, as has been shown, does
not furnish a satisfactory explanation of the significance of i
in the case of electrolytes. This value of i varies in all cases
with the nature of the solvent and also, in general, with the
strength of the solution ; and it does not always vary to the same
extent nor even in the same sense in different solutions. It is
clear then, that when the simple equation PV=RT is applied to
a solution, only approximate results are obtained at best, unless
experimental data are at hand showing that in the particular

1 Compare here the warning words of Lothar Meyer, in his article,— Das Wesen
des osmotischen Druckes. Zeit. phys. Chem. 5, 23 (1890). Also the reply of van't
Hoff, IMd., p. 174.

350 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

case and for the particular concentration under consideration i
is actually equal to unity.

It must be fully and freely admitted that the dissociation the-
ory has done much good in stimulating research in many lines.
It has been fruitful in proportion to the amount of truth con-
tained in it. Like other theories founded upon too narrow a
basis of induction, it has gradually been outgrown, — the facts
are too much for it. It would be difficult of course to say of any
theory — even of one long ago discarded — that it is entirely
worthless, and so the writer has no inclination to make such a
statement concerning the dissociation theory. And further he
would not be understood as having the remotest intention to be-
little in any way the work done by the enthusiastic adherents
of the theory of electrolytic dissociation, for this will no doubt
always form a bright page in the history of the development of
chemistry and of science in general.

It is solely because of the rapid growth of the erroneous idea
that the deductions drawn from the indiscriminate application
of the simple gas equation to solutions and from the notion that
all well known facts harmonize with the theory of electrolytic
dissociation, that I have felt compelled to call attention to the
real status of the experimental facts underlying these deduc-
tions. It is hoped that this will stimulate to renewed experi-
mental activity, for surely our theory of solutions leaves much
to be desired. The analogy between gases and solutions does
not help us to understand even moderately concentrated solu-
tions ; and whenever experimental work on such solutions is
done, the assumption that there is chemical union between solv-
ent and dissolved substance calls for recognition. That there is
chemical union between solvent and dissolved substance, in many
cases at least, there can be no doubt ; and as for the osmotic pres-
sure, the outcome of that mutual attraction between solvent and
dissolved substance, its various excentricities and caprices, as ex-
hibited even in moderately concentrated solutions, show clearly
that it is closely related to, if not essentially identical with,
chemical affinity. Our hope in the study of solutions lies in
the recognition of this. The problem of solutions is pre-

KAHLENBERO — THEORY- OF ELECTROLYTIC DI880CIATION. 351

eminently one for the chemist. Each solution will have to be
examined separately and then it will appear that chemically
analogous solutes in the same solvent will have a similar be-
havior, the closeness of the agreement being determined by the
degree of the analogy; and finally from such a study of solu-
tions, which can and should begin with the most concentrated,
the behavior of the most dilute solutions will appear as a limit-
ing case, — and then we shall see the present theory of solutions
in its true relation to the facts. And finally, as far as the an-
swer to the question, — What must be the relation between solvent
and dissolved substance in order that the resulting solutions
may conduct electricity?1 — is concerned, we are unfortunately
as yet in the dark ; just as we do not know why certain solids
conduct electricity and others do not. The essence of electrical
conduction in electrolvtes and that in metals is, after all, not so
radically different as is frequently supposed. The further ex-
perimental investigation of the general problem of electrical
conduction will, let us hope, ere long give us the true key to the
situation.

Laboratory of Physical Chemistry,

University of Wisconsin,

Madison, May, 1901.

^The investigation of D. Konowalow [Wied. Ann. 49, 733 (1893)] are of special
interest in this connection.

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BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 49

Science Series. Vol 2, No. 6. pp. 353-339

ON THE DIELECTRIC CONSTANTS OF PURE SOLVENTS

BY

HERMAN SCHLUNDT, Ph. D.

Instructor in General and Physical Chemistry

Published tn-monthlp by authority of law with the approval of the Regents

nf the University and entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
July, 1901

$MU*tin of tJt* ||(ttU*£**rttjj of pJidJConsin*

Committee of $Jwt>ltcattxm
CHARLES KENDALL ADAMS, President of the University

WILLIAM HERBERT HOBBS, Editor-in-Chief

EDITOR*

Richard T. Ely, Economics and Political Science Series

William H. Hobbs, Science Series

J. B. Johnson, Engineering Series

Charles Forster Smith, Philology and Literature Series

Frederick J. Turner, History Series

BULLETIN OF THE UNIVERSITY OF WISCONSIN

NO. 49

Science Series, Vol 2, No. 6, pp. 353-309

ON THE DIELECTRIC CONSTANTS OF PURE SOLVENTS

BY

HERMAN SCHLUNDT, Ph. D.

Instructor in General and Physical Chemistry

LIBRARY
NEW YORK
BOTANICAL

OARDfcN.

Published bi-monthly by authority 0/ law with the approval of the Regents

of the University a?id entered at the post office at

Madison as second-class matter

MADISON, WISCONSIN
July, 1901

ON THE DIELECTRIC CONSTANTS OE PURE

SOLVENTS.

Introduction.

In 1893 Nernst,1 from theoretical considerations based upon
the theory of electrolytic dissociation, deduced his well known
rule, that — other things being equal — the greater the dielectric
constant of a medium the greater is its dissociating power. In
the same year J. J. Thomson2 also pointed out this relation,
saying that if we accept the view that the forces between the
atoms are electrical in their origin then the effect of surrounding
the molecules of a substance by a medium possessing a very
high dielectric constant like water, would be to practically dis-
sociate them. According to Nernst, proportionality between the
dielectric constant and dissociating power need not necessarily
exist, but a close parallelism between the two doubtless pre-
vails. He adds that other factors besides the dielectric constant
doubtless exist, which probably influence the dissociating power
of the solvent. The experimental facts, Kernst3 says, show
beyond a doubt that a marked parallelism exists between the dis-
sociating power and the dielectric constant. Exceptions to the
rule he explains by assuming the existence of specific influences,
of which the association of the ions with the molecules of the
solvent is probably of prime importance.

The existing experimental data at the time the above relation
between the dielectric constant and dissociating power was
pointed out accorded well with it, and subsequent investigations
furnished numerous additional examples in support of it. But

1 Gottinger Nachrichten No. 12, (1393) ; Zeit. phys. Cham. 13, 531, (1894).

* PhiL Mag. 36, 320. (1893).

3 Theoretische Chernie p. 355. (Dritta Auflage).

356

BULLETIN OF THE UNIVERSITY OP WISCONSIN.

exceptions also appeared which point to a marked specific in-
fluence of the solvent. Some of these exceptions are noted and
considered in another part of this paper.

The following table taken from Nernst's1 Theoretical Chem-
istry illustrates the general parallelism between the dielectric
constant and the dissociating power.

Table I.

Medium.

Dielectric
Constant.

Electrolytic Dissociation.

Gas

1.0
2.3

4.1

25
62
80

Not perceptible at ordinary temperatures.

Benzene

Exceedingly low ; but distinctly perceptible

Ether

conductivity indicates traces of dissocia-
tion.

Perceptible conductivity of dissolved electro-

Alcohol

lytes.
Dissociation quite marked.

Formic acid

Marked dissociation of dissolved salts.

Water

Very marked dissociation.

Since the formulation of the ISTernst-Thomson rule excellent
new methods for determining dielectric constants have been de-
vised by Thwing, 2 Nernst, 3 and Drude ; 4 and these investigators
have measured the dielectric constants of a number of sub-
stances. The pupils of Nernst, and of Drude, and others have
elaborated, modified and perfected these methods, so that the
determination of dielectric constants at ordinary temperatures
is now a comparatively simple operation. During this period
the electrical conductivity of non-aqueous solutions has also re-
ceived considerable study, and the dissociating power of various
solvents, which yield conducting solutions, has moreover been
investigated by means of cryoscopic and boiling-point determin-
ations. The selected examples given in the following table will
serve to show that various other solvents besides water possess
ionizing power in a very marked degree. Under V, in the third

i P. 365, third edition. (1900).

' Phys. Review, 2, 35. (1894). Also Zeit. phys. Chem. 14, 286. (1894).

3 Zeit, phys. Chem. 14, 622. (1S94).

* Zeit. phys. Chem. 23, 267. (1897).

SCHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 357

column, the volume in liters is given in which one gram mole-
cule of substance is dissolved; and the next column gives the
corresponding molecular conductivity, while the fifth column,
gives the temperature at which the measurements were made.

Table II.

Solvent

Water.

Methyl alcohol

Formic acid

Liquid ammonia

Liquid sulphur dioxide.

Acetone.

Benzonitrile

Acetonitrile

Pyridine

Solute

Phosphorus oxy-chioride

Arsenic trichloride

KI

LiCl

KC1

KBr

N(C2H5) I

4

KI

AgN03

AgN03

NH4I

SCCH3) I
3

S(CHS) I

V

Dv

2

99.7

100

116.1

1000

120.3

11.7

40.1

117.4

57.5

1174.0

65 3

32

40.7

1024

57.8

301.9

210.6

1354

272.9

65040

340.2

16

43.1

128

51.6

1024

54.8

144.7

109.4

1157.6

145.8

9.43

5.2

151.96

16.4

8

54.5

128

118.3

79

16.7

1264.32

36.9

204

26.4

1224

38.2

250

51.4

1500

66 6

t°c

18

18

25

-38

25

25

25

25

25

Observer

Kohlrausch ')

Vollmer 3)

Zanninovich-Tessa-
rin 3)

Franklin and
Kraus *)

Walden 6)

18 St. v. Lascynski •)

Lincoln ')

Dutoit and

Friderich e)

St. v. Lascynski and
St. v. Oorski »)

Walden 10)

Walden10)

1 Wied. Ann. 36, 161. (1885).

2 Wied. Ann. 53, 328. Q894).

• Zeit. Elektrochem. 3, 55. (1895).

7 Jour. Phys. Chem. 3, 457. (1899).
3 Zeit. phys. Chem. 19, 251. (1896\ 8 Bull. Soc. Chem. [3] 19, 327. (1898).

* Am. Chem. Jour. 23, p. 288. (1900). 9 Zeit. Elektrochem. 4, 290. (1897).

6 Ber. d. Deutsch. Chem. Gesel. 33, 2862. (1899). I0 Zeit. anorg. Chem. 35, 209. (1900).

358 BULLETIN OF THE UNIVERSITY OP WISCONSIN.

The dielectric constants of the last four solvents given in the
table have, to my knowledge, not been determined before. That
these solvents possess marked dissociating power the results
given in the table clearly show. Hence by the Nernst-Thom-
son rule they should have high values for their dielectric con-
stants. The dielectric constant of benzonitrile was measured
by Drude,1 and found to be 26.0 at 21° C. Drude also meas-
ured the dielectric constant of benzyl cyanide, but his extensive
investigation does not include any of the nitriles of the aliphatic
series. The dielectric constant of liquid ammonia was meas-
ured by Goodwin and Thompson2 who found the value 22.0 at
— 34° C, and by Coolidge,3 who gives the value 16.2 at 14° C.
The substituted ammonias, Prof. Kahlenberg4 finds, also yield
good conducting solutions. In view of the great dissociating
power of the nitriles and the substituted ammonias it seemed of
special interest to determine the dielectric constants of these
compounds, and at Prof. Kahlenberg's suggestion this work was
undertaken. The investigation also embraces a number of
other organic compounds containing nitrogen, and includes most
of the inorganic solvents in which Walden5 made electrical con-
ductivity measurements.

During the progress of his researches on non-aqueous solu-
tions, Prof. Kahlenberg collected a choice lot of preparations
which he kindly placed at my disposal. This greatly facili-
tated the experimental part of my work, and I desire to express
to him my thanks for this favor.

Method and Apparatus.

In measuring the dielectric constants the method devised and
elaborated by Drude6 was used. It is unnecessary for me to
give a complete description of this method and of the details of

1 Zeit. phys. Chem. 33, 309. (1897).
» Phys. Rev. 8. 38. (1899).
8 Wied. Ann. 69, 140. (1899;.
* Jour. phys. Chem. June (1901).

6 Ber. d. Deutsch. Chem. Gesel. 32, 2852, (1899). Zeit. anorpr. Chem. 85, 209. H900).
8 Zeit. phys. Chem. 83; 267. (1897). See also Wied. Ann. 53,633. (1835); 58, 1;59,
17 (1806) ; 60, 28, 500, (1897).

SCHLUNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS. 359

the apparatus employed. The reader is referred to Drude's
original articles, after reading which the additional remarks on
the method contained in the paragraphs that now follow will be
much better understood.

The apparatus used for these measurements was a trifle larger
than the one described by Drude. The wave-length of the elec-
trical waves in the two parallel wires in air was about 84 cm. as
compared with 74 cm. of the apparatus employed by Drude. A
vacuum tube containing hydrogen was used to determine the. set-
tings for maximum resonance. It served very well indeed for
this purpose.

Of the two methods described by Drude the first is the more
accurate, but it necessitates the use of comparatively large quan-
tities of substance, at least 200 cc, which, in most cases, were not
available. Moreover, the poisonous nature of many of the com-
pounds made it desirable to work with small quantities which
could be kept in a closed cell while under investigation.
Drude's "second" method, although less accurate, was therefore
chosen. This method enables one to operate with less than a
cubic centimeter of solvent and gives results accurate to within
two per cent. In this method the substance to be measured is
introduced into a small condenser which is placed in the sec-
ondary circuit. The length of the secondary circuit is then ad-
justed for maximum resonance. The dielectric constant cor-
responding to the length noted is found from a calibration curve
representing the results obtained in calibrating the apparatus
for the particular condenser.

Four cells similar in form but of different capacities served as
condensers. The apparatus was calibrated for each cell with the
liquids recommended by Drude, namely : benzene, acetone, water,
mixtures of benzene and acetone, and mixtures of acetone and
water. Seventeen liquids whose dielectric constants range from
2.26 to 80.9 at 19° C. were prepared. The benzene used for
these calibrating solutions was Kahlbaum's thiophene free prep-
aration, purified by crystallization. Its boiling point was
79.2° C. under 744.6 mm of pressure. The acetone was like-

360 BULLETIN OP THE UNIVERSITY OP WISCONSIN.

wise KahlbauHi's preparation — it was prepared from the bisul-
phite compound. It boiled at 55.7° C. under 746 mm of pres-
sure. The water used had a specific conductivity of 3.6 X 10-6.
In calibrating, the "zero" of the apparatus, obtained by plac-
ing a straight piece of copper wire in place of the cell, was fre-
quently redetermined, as a change in the position of certain
parts of the apparatus may produce a change of the "zero" point.
This precaution was also taken whenever solvents of unknown
dielectric constants were under examination. As a check on any
change in the capacity of the cells, the calibrating liquids whose
dielectric constants were nearest in value to that found for the
solvent under examination were introduced into the cell and the
settings for maximum resonance determined. In this way any
change in the position of the condenser plates could be readily
detected. This procedure also gives all the necessary data for
calculating the dielectric constant according to the formula
given by Drude :l

. 2 7T 1 .2*1*

cot — j. cot — , — -

D = D1 + (D8-2>1)— 1^f- -j^

COt j-= COt j-i

A A

in which a is the wave-length of the electric waves in air, D is
the dielectric constant sought, I is the setting for maximum res-
onance when the cell contains the solvent whose dielectric con-
stant is sought; Dt, h and D2, l2, are the dielectric constants and
settings of the calibrating solutions. In working with pyri-
dine the dielectric constant was calculated by this formula using
84 cm for a. . The value found was the same as the value ob-
tained with the aid of the calibration curve.

From 10 to 30 settings for maximum resonance were made
for each solvent examined, and the average of these was the value
used for obtaining the dielectric constant.

The methods of dehydrating and rectifying the various solv-
ents will be found under the head of each particular solvent in
the statement of results given below.

A series of trial experiments was at first made with the appa-

1 Zeit. phys. Chem. 33, 309. (1397).

SCHLUNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS. 361

ratus in order to test it thoroughly. The dielectric constants of
ethyl ether, chloroform, ethyl benzoate, salicylic aldehyde, ben-
zonitrile, and nitrobenzene were measured, and the' results ob-
tained agreed very well with those given by Drude. It is there-
fore entirely superfluous to again report the numerical results
obtained for these substances.

Experimental Results.

THE XITRILES.

The dielectric constants of the following aliphatic nitriles
were measured: Hydrocyanic acid, acetonitrile, propionitrile,
butyronitrile, iso-propyl cyanide, valeronitrile, iso-butyl cyanide,
capronitrile, and ethylene cyanide. In the aromatic series, ben-
zonitrile, benzyl cyanide, ortho-toluonitrile, mandelic nitrile,
and a- and /?- naphthonitriles were measured.

Hydrocyanic Acid. — The sample of hydrocyanic acid used was
prepared in the usual way by slowly adding a strong aqueous
solution of potassium cyanide to sulphuric acid of Sp. Gr. 1.25
in a retort connected with a reflux condenser kept at 30° C.
The gas was then dried at 30° C. by passing it through a series
of three large U tubes, kept at 30° C, and containing fused
calcium chloride. The gas was condensed in a tube provided
with glass stopcocks, suspended in a bath at 0°. A colorless
liquid was thus obtained which left no residue upon evapora-
tion. Some of the liquid was introduced into the cell adapted
for the measurement of liquids having a high dielectric constant.
The cell was securely stoppered and the measurements were
made at 21° C. jSTo appreciable absorption was observed, the
position for maximum resonance being about as well defined
as in the case of acetone. The D. C.1 found is higher than the
D. C. of w^ater. This necessitated an extrapolation of the cali-
bration curve in order to get an approximate value. The D.
C. obtained in this way is 95.0 ± 3.5 After this exceedingly
high result had been obtained a second sample of hydrocyanic

i The abbreviation D. C, is used for dielectric constant in the presentation of the re-
salts.

362 BULLETIN OP THE UNIVERSITY OF WISCONSIN.

acid was prepared by redistilling the first sample from a water-
bath kept at 30° C. The gas was again passed through the dry-
ing tubes and condensed as before. Measurements with this
sample gave the same readings for maximum resonance as in the
first case. The temperature coefficient is negative, but it was
not accurately determined.

Acetonitrile. — The sample of acetonitrile first measured was
obtained by distilling a sample of Kahlbaum's make. Its boil-
ing point was very constant, being 80.9° C. under a pressure of
745 mm.. The average of four determinations gave the value
36.5 for the D. C. at 21° C.

A second sample, prepared by Prof. Kahlenberg from the
Kahlbaum preparation by dehydrating it with phosphorus pen-
toxide, and redistilling twice, was measured. Its boiling point
was 80.7 under a pressure of 749 mm. The measurements were
made at 22° and gave the same result as was obtained with the
first sample.

A third sample, also furnished by Prof. Kahlenberg, was
finally measured. This sample was twice dehydrated with
larger quantities of phosphorus pentoxide than were used in the
previous case, and was distilled from phosphorus pentoxide. It
had a boiling point of 80.2° C. under a pressure of 736 mm.
The D. C. was calculated by the formula previously given, and
found to be 36.1 at 21° C.

Propionitrile. — This sample was Schuchardt's preparation.
Its boiling point was 94.6° under a pressure of 749 mm. The
average of four determinations at different times gave the value
26.5 for the D. C. at 22° C. The absorption was slight.

Butyronitrile. — The sample tested was Schuchardt's prep-
aration. It was redistilled from calcium chloride. Its boiling
point was 116.5° to 118° C. under 742 mm of pressure. The
average of three different determinations is 20.3 at 21° C.

Iso-propylcyanide. — The sample was Schuchardt's prepara-
tion. It was dehydrated with calcium chloride and redistilled.
Its boiling point was 106°-107° C. under 744 mm of pressure.

6CHLUNDT — DIELECTRIC CONSTANTS OF TURE SOLVENTS. 363

The average of three determinations gave the value 20.4 for its
D. C. at 24° C.

Valeronitrile (normal). — The sample was obtained from
Schnchardt. It was redistilled from calcium chloride, and the
portion which distilled between 137° and 139° 0., under 743
mm of pressure was taken for the measurements. The D. C.
was found to be 17.4° at 31° C.

Iso-butylcyanide. — The sample was Schuchardt's make; it
was redistilled from calcium chloride, and the portion distilling
between 129° and 130.5° C, under a pressure of 742 mm was
taken for the measurements. Its D. C. was found to be 17.95 at
22° C.

CapronltriJr. — The sample used was obtained from Schu-
chardt. It was redistilled from calcium chloride, and the por-
tion distilled between 153c-154.2° C, under 743 mm pressure,
was taken for the measurements. Its D. C. was found to be
15.5 at 22° C. The higher members of the series show a slight
amount of absorption, but the maximum resonance is still well
enough denned without increasing the intensity of the oscilla-
tions in the secondary circuit.

Ethylene Cyanide. — The sample of succinic acid nitrile was
of Schuchardt's make. It was treated with fused calcium chlor-
ide, filtered and redistilled twice under diminished pressure.
Its boiling point was 168° C. under a pressure of 28 mm. A
solid, almost colorless, amorphous compound was thus obtained
which melted at 54° C. Its D. C. was measured in the form of
cell used by Drude1 for the measurement of substances at higher
temperatures. During the measurements the cell was kept in
an oil-bath of the form figured and described by Coolidge.2 The
bath was attached to the ebonite slide by means of a small spring
clamp. The temperature was kept at 60° ± 1° during the
measurements of the liquid ethylene cyanide. The average of
three determinations gave the value 61.2 for its D. C. The D.
C. of the solid compound was also determined. Three determi-

i See Fig. 7, p. 285, Zeit. phys. Chein. 23. (1897).
8 Wied. Ann. 69, 133. (1899).

364 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

nations averaged 65 . 3 at 23° C. No sudden change in the D. C.
was observed at the melting point. The absorption of the solid
ethylene cyanide was very slight ; but the liquid sample did not
show a well defined maximum, which was found to be due to its
greater conductivity. The qualitative measurements of its re-
sistance show that the temperature has a great influence on the
resistance. At room temperatures the resistance is about twenty
times as great as it is at 60° C. ; but no sudden change in the
resistance was observed at the melting point.

Toluoniirile (ortho.). — Schuchardt's preparation was redis-
tilled from calcium chloride. A straw colored distillate, boiling
at 200° — 201° C. under a pressure of 733 mm. was thus ob-
tained. It D. C. was found to be 18.5 at 23° C. It showed
slight absorption.

a-Naphthonitrile. — Schuchardt's preparation was redis-
tilled under diminished pressure. Its melting point was 37° C. ;
but it is easily kept in a liquid state at 20° C. when the solid
phase is not present. Its dielectric constant was determined in
the form of cell adapted for measurements at higher tempera-
tures, and the following values were found for the liquid sample.

D. C. = 16.0 at 70° C.
D. C. = 17.9 at 42° C.
D. C. = 19.2at22° C.

The position for maximum resonance was about as well de-
fined as for nitro-benzene whose absorption index Drude1 places
at 0.05. The D. C. of the solid sample was found to be 6.3 at
21° C. ; but this value is only approximate, for the position for
maximum resonance was not well defined.

0-Naphthonitrile. — Thes ample used for the measurements
was obtained by distilling Schuchardt's preparation under di-
minished pressure. Its boiling point was 190° C. under 35 mm.
of pressure, and its melting point was 64° C. The D. C. of the
liquid was found to be 16 . 9 at 70° C, and for the solid the value
4.3 at 23° C. was obtained, the position for maximum resonance
being well defined in both the solid and the liquid samples.

i Zeit. phys. Chem. 23, 309. (1897).

SCHLUNDT DIELECTRIC CONSTANTS OF PURE SOLVENTS. 365

Mandelic Nitrile. — The preparation from which the sample
was obtained was of Schuchardt's manufacture. It showed de-
cided signs of decomposition, being of a dark brown color and
somewhat syrupy. It was dehydrated with fused calcium chlor-
ide, was filtered and distilled under diminished pressure, and the
sample thus obtained was redistilled. Its boiling point was 94°
C. under a pressure of 50 mm. A mobile, colorless liquid was
thus obtained whose specific conductivity was found to be 2.2
X 10"10 reciprocal ohms. Its dielectric constant was found to be
17.82 at 23° C. An absorption of about the same order as
that of nitrobenzene was observed. Its absorption index was
also determined by the method outlined by Drude.1 The value
obtained in this way was . 045, which agrees very well with that
of nitrobenzene which Drude places at .05. Drude has found
that this anomalous absorption is characteristic of compounds
containing hydroxyl.

THE SUBSTITUTED AMMONIAS.

The amines whose dielectric constants were measured are
enumerated in Table III. The samples used were Schuchardt's
preparations with the exception of the two toluidines and the
xylidine which were of Trommsdorff's manufacture. Each
sample, except methylamine, was dehydrated with fused potas-
sium hydroxide and then distilled ; and in many cases the distil-
late was again treated with fused potash and redistilled. The
sample of methylamine was doubtless impure for, upon evap-
oration it left a residue, and it did not yield a well defined
position for maximum resonance, while with all the other sam-
ples well defined maxima were observed. Hence the value
found for the D. C. of methylamine is doubtless too high.

The third column in the following table gives the boiling
point of the samples taken for the measurements, and the 'fourth
column indicates the corresponding barometric pressure, while
the last column gives the temperature at which the D. C. was
measured.

1 Zeit. phys. Chem. 23, pp. 292-297. (1S97;.

366

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table III.

Name.

Formula.

B. P.

P.

D. C.

t°C

Metbylamine

CH3 NH8
CSH5 NH8

< 10.5
6.17

21

< 17.5

752

21

Iso-propylamine

(CHs)

}CU NH2
|CHsi

36

750

5.45

20

Butylamine (n)

C4 H9 N H2

76-77

740

5.30

21

Iso-butylamine

(CH3)

< £CH. CH2 NH8

(CBS)

63

745.2

4.43

21

C5 Hj 1 NH2
(C2 Hs)2 NH
(C3 H7)2 NH
(C4H9)2 N H

91-95
54.5
108-108.5
134.5

740.4
733.4
745.5
735

4.50
3.58
2.90
2.65

22

Di-ethylamine

21

Di-propylamine

22

Di-iso-butylamine

22

Trimethylamine

N(CH3)3

C6H5 NH2

(NH2 (1) )

C«H4 [

<CH3 (2) )

< 8°
179.4

194.5

750
741

738

2.95

7.2

5.93

4

19

Toluidine (o)

20

Toluidine (m)

(NH2 (1) )

C6H4 \ [

(CHs (3) )

194.2

738.2

5.95

20

rcH3 n

Xylidinel:3:4

C6 Hs -iCH3 3}-

1 1
INH34J

209.5

737.0

4.90

20

MoDO-methylaniline

C6 H5 NHCH3

189.4

740.5

5.8

20

C6 HB N(CH3)2

191.5

735

5.07

20

(C7 B.7)2 NH

200

40

3.55

20

MISCELLANEOUS ORGANIC COMPOUNDS.

Pyridine. — The sample was Schuchardt's preparation. It
was redistilled and found to "boil from 115.5° to 117° C. un-
der 745 mm. of pressure. With this several measurements were
made, the average of the results for the D. C. being 12.35 at
21° C.

A second sample was furnished by Prof. Kahlenberg. Kahl-
baum's best preparation was carefully purified according to the
method given by Ladenburg.1 The portion boiling at 114° C.

i Liebig Ann. 247, 1. (1888).

8CHLUNDT DIELECTRIC CONSTANTS OF PURE SOLVENTS. 367

under 744. 6 mm. of pressure was used for the measurements.
The D. C. was found to be 12.55 at 20° C, a result which agrees
well with the foregoing. The settings for maximum resonance
were well denned.

a-Picoline. — The sample was Schuchardt's preparation.
It was treated with fused calcium chloride, and redistilled. The
boiling point of the portion taken for the measurements was
128.5° — 129.5° C. at 736 mm. of pressure. The value
found for the D. C. is 9.8 at 20° C.

The unpurified sample of pyridine, it will be noted, gave a
slightly lower D. C. than the purified sample. The former
very likely contained a slight amount of picoline.

Quinoline. — Two samples of quinoline were measured. The
first was obtained by redistilling Schuchardt's preparation
marked, "Quinoline from Coal Tar." The portion which dis-
tilled at 232° C. under 746 mm. of pressure was measured.
Its D. C. was found to be 8 .7 at 22° C.

The second sample was a synthetic preparation, made by
Messrs. Maxon and Thomas in this laboratory according to the
method of Skraup. The boiling point of the sample measured
was 232° C. under 746 mm. of pressure. Its dielectric constant
was found to be 8 . 9 at 20 . 5° C. The agreement is close enough
to fall within the limit of error. The absorption is slight.
These values of the D. C. agree well with the result, 8.9,
obtained by Turner1 who worked with JSTernst's apparatus.

Piperidine. — The sample was E. de Haen's preparation. It
w&s redistilled and the portion distilling between 105.5° and
107.0° C. under a pressure of 745 mm. was used for the meas-
urements. It was an almost colorless liquid and showed no ab-
sorption. The value found for its D. C. was 5.8 at 22° C.

Carbon dichloride. — The sample was of Schuchardt's make.
Its boiling-point was 118° at 726.5 mm. of pressure. The value
2.46 was found for its D. C. at 21° C.

Nitromethane. — Schuchardt's preparation was treated with
fused calcium chloride and redistilled. Its boiling-point was

1 Zeit. phys. Chem. 35, 385. (1900).

368 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

99.9° under a pressure of 738.4 mm. The dielectric constant
found was 40.4 at 19° C. Thwing1 gives the value 56.36 at
15° C.

Nitroethane. — Schuchardt's preparation was dehydrated and
rectified as in the case of nitromethane. Its boiling-point was
110.5° C. at 738.3 mm. of pressure. The value of its D. C.
was found to he 29.5 at 18° C.

Methyl Nitrate.— -The sample of methyl nitrate used for the
measurements was prepared from Kahlbaum's best methyl alco-
hol by treating it with nitric acid according to the method of
J. Lea.2 The sample was washed with water containing a
small amount of sodium carbonate, and was dehydrated with
fused calcium chloride and finally distilled from a waterbath.
Its boiling point was 64.4° C. at 730.2 mm. of pressure. The
value 23.5 was found for its D. C. at 18° C. No absorption
was observed.

Ethyl Nitrate. — Schuchardt's preparation was washed with
water containing a trace of sodium carbonate to remove traces of
nitric acid and alcohol. It was then dried with fused cal-
cium chloride and redistilled twice. The boiling point was
86.1° at 729.4 mm. of pressure. The average of three determi-
nations gave the value 18.3 at 18° C. Thwing found the value
17.72 at 15° and Drude found 19.6 for the D. C. of this com-
pound at 17° C.

Propyl Nitrate. — This compound was prepared according to
the method of Wallach and Schulze. 3 The propyl alcohol used
for its preparation was redistilled. Its boiling-point was 95.8°
under a pressure of 752 mm. The sample of propyl nitrate was
dehydrated and rectified as described for ethyl nitrate. Its
boiling point was 108.5° C. under a pressure of 738.5 mm.
The value 13.9 was obtained for its D. C. at 18° C.

Iso-butyl Nitrate. — Schuchardt's preparation was redistilled.
Its boiling-point was 120.0° under 738.2 mm. of pressure.

i Physical Review. 2, 35. (1894).

2 See Beilstein, Handbuch der Organischen Cbemie. (Third edition) Vol. I, p. 324.

3 Ber. d. Deutsch. Chem. Gesel. 14, 422.

SCHLTJNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS. 369

One scries of measurements was made which gave the value
11.7 for its D. C. at 19° C.

Iso-propyl Nitrite. — A sample of iso-propyl nitrite, prob-
ably not entirely free from nitrous acid, was measured. The
value 11.5 was found for its D. C. at 19° C.

Ethyl Uretliane. — The sample used for the measurements was
kindly furnished by the School of Pharmacy of this University.
Its melting-point was 48° C. The value found for the D. C.
of the liquid compound at 60° was 13.6 ; the solid form gave the
value 3.18 at 23° C.

Amylsulph-hydrate. — The boiling point of the sample was
116.5° C. under 752 mm. of pressure. The D. C. found was
4.35 at 22° C.

INORGANIC SOLVENTS.

Phosphorus Trichloride. — The sample used was of Kahl-
baum's manufacture. It was redistilled, boiling at 74.1° C.
under a pressure of 740 mm. The average of two determina-
tions gave the value 3.36 for its D. C. at 22° C. No absorption
was observed.

Arsenic Trichloride. — The sample which served for the
measurements had been prepared in this laboratory by Dr.
Lincoln. It was dried with fused calcium chloride and was
redistilled. The sample used boiled from 127° — 128° C. un-
der 740 mm. of pressure. The value 12.35 was obtained for
its D. C. at 21° C. Slight absorption which was doubtless due
to conduction was observed.

Antiraony Trichloride. — The sample used for the measure-
ments conducted about as well in the fused state, at 70° C, as a
fiftieth normal sodium choride solution. The position for max-
imum resonance was still well enough defined without increas-
ing the intensity of the oscillations in the secondary circuit, but
the absorption was more marked than with arsenic trichloride.
Hence it seemed advisable to determine the D. C. by the
method outlined by Drude1 for substances which show absorp-

3 See Drude Zeit. phys. Cherc. 23, pp. 294-297.

370 BULLETIN OF THE UNIVERSITY" OF WISCONSIN.

tion. The value thus obtained was 33.2 at 75° C. For the
solid compound the value 5.4 was found at 18° C.

Antimony Pentachloride. — The sample used was E. de Haen's
preparation. It was found securely stoppered and hence was
not rectified. The value 3.78 was obtained for its D. C. at
21.5° C.

Stajmic chloride. — Kahlbaum's preparation was redistilled.
Its boiling-point was 117.5° C. under 750 mm. of pressure.
The value found for its D. C. is 3.2 at 22° C.

Sulphur Mono-chloride. — The sample used for the measure-
ments had been prepared in this laboratory by Mr. Harry Eg-
gers. It was redistilled and found to boil at 136.2° under 738
mm. of pressure. The value 4.8 was found for its D. C. at 22°
C.

Sulphur Trioxide. — A sample of Kahlbaum's sulphur triox-
ide was measured in both the solid and liquid states. The value
3.56 was obtained for the D. C. of the liquid sample at 21°,
and 3.64 for the solid at 19° C.

Phosphorus Oxy chloride. — The sample used for the measure-
ments was prepared according to the method described by Ger-
hardt.1 About 150g of phosphorus pentachloride was mixed
with one-half its weight of dry oxalic acid in a retort, and heated
gently. The distillate thus obtained was redistilled and found
to boil at 105.1° under a pressure of 739.2 mm. The value ob-
tained for its D. C. was 13.9 at 22° C.

Sulphury Ichloride (S02C12). — This compound was pre-
pared by the method of Schulze.2 A quality of camphor was
liquefied by passing dry sulphur dioxide into the containing
vessel. Dry chlorine gas was then passed into the liquid and
the current of sulphur dioxide was also continued. In the
presence of the camphor chlorine and sulphur dioxide unite to
form sulphuryl-chloride. After several distillations a product
boiling at 68.4° under 740.2 mm. of pressure was obtained.
The value 9.15 was found for its D. C. at 22° C.

1 Ann. Chim. et de Phys. [3] 44, 102.

2 Jour, prakt. Chem. 23, 351.

SCHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 371

Thionyl chloride (SOCI2). — The sample used for the meas-
urements was prepared in the usual way, namely, by the
reaction of dry PCI, with dry S02. [PC15 + S02 = POCl3 +
SOCl2]. About 150g of PC15 was placed in a retort connected
with a reflux condenser and a stream of S02 was conducted
in till the PC13 had become liquefied ; another portion of PC15
was then added, and the stream of S02 was continued. The
liquid thus obtained was heated for some time, with the return
condenser still attached, to free it from S02 ; and finally, by re-
peated fractional distillation a sample of SOCL was obtained
which had a constant boiling point cf 76.8° under a pressure of
751.3 mm. The value found for its D. C. is 9.05 at 22° C.
Slight absorption was observed.

Liquid Sulphur Dioxide. — A sample of liquid sulphur di-
oxide was measured in a sealed cell. The value found for its
D. C. at 22° is 12.35. Linde,1 by Nernst's method, found the
value 14.8 at 23°, while Coolidge2 found the value 13.75 at
14.5.° I made but one determination.

Bromine. — The sample of bromine used for the measurements
was prepared by Miss Winifred Titus from potassium bromide,
potassium bromate, and sulphuric acid according to the method
of J. S. Stas.3 The value 3.18 was obtained for its D. C. at
23° C. The measurements were made soOn after the bromine
had been introduced into the cell, so as to minimize the action of
the bromine on the platinum plates.

Iodine. — Pure resublimed iodine obtained from the chemical
works of de ITaen at List near Hannover was once more sub-
limed by Prof. Kahlenberg. An attempt was made to determine
its D. C. in the solid and the liquid states in a sealed cell. With
the solid sample the position for maximum resonance was still
fairly well defined, but after removing the iodine from the cell
it was found, that the plates of the condenser were covered with
a black coating, which doubtless introduced an error. Hence

1 Wied. Ann. 56, 516. (1805).

2 Wied. Ann. 69, 130. (1899).

3 Unters. iiber Proport. u. Atomg. Leipzig, 18S7, p. 220. See also Fehling's Handworter-
buch d. Chemie. I, p. 235,

3

372

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

the value 10.3, which was found for its D. C. at 23°, must be
regarded as only approximate. With the liquid sample no dis-
tinct maximum resonance was obtained.

Cyanogen (Liquid). — In view of the high dielectric constant
obtained for hydrocyanic acid it seemed of special interest to de-
termine the D. C. of liquid cyanogen. Prof. Kahlenberg kindly
offered to undertake the preparation of this compound with me.
We evolved the cyanogen by treating a strong solution of copper
sulphate with a concentrated solution of potassium cyanide.
The gas was dried by passing it through two large U-tubes filled
with fused calcium chloride. It was condensed by means of
solid carbonic acid. The D. C. was measured in a sealed cell at
23° C. We found the value 2.52, the position for maximum
resonance being well defined.

All the foregoing results are summarized in the following
table, in which the abbreviations (1.) and (s.) are used for
liquid and solid respectively.

Table IV.

Name.

Cyanogen (1)

Hydrocyanic acid (1)

Acetonitrile

Propionitrile

Butyronitrile (n)

Iso-propyl cyanide

Valeronitrile (n)

Iso-butyl cyanide

Capronitrile

Ethylene cyanide (s)

Ethylene cyanide (1)

<* — Naphthonitrile (s) . . .
« — Naphthonitrile (1)...
"—Naphthonitrile (1)...
^—Naphthonitrile (s)...
/?— Naphthonitrile (1)...
Mandelic nitrile

Formula.

CCNJa
HCN

CH3 CN

C2 H5 CN

C3 H7 CN
(CH3)2 CHCN

C4 H6 CN

(CH3>2 CHCHS CN
(CH3)2 CHCHoCHa

C2 H4(CN)a

C2 H4 (CN>8

Cio H,CN

Ci o H7 CN

Cio H7CN

Co H7CN

C10 H7 CN

C6 HB CHOHCN

CN

23
21
21
22
21
24
21
22
22
23
60
21
42
70
21
70
23

D. C.

2.52
95.
36.4
26.5
20.3
20.4
17.4
17.95
15 5
65.3
61.2

6.3 7
17.9
16.0

4.3
16.9
17.82

8CHLTJNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS.

373

Table IV — Continued.

Name.

Benzonitrile 1)

Benzyl cyanide a) .. .
Toluonitrile (ortbo).

Pyridine

^-Picoline

Piperidine

Qninoline 3)

Carbon dichloride.. .
Ethyl sulph-hydrate .
Ethyl urethane (s).. .
Ethyl urethane (1). . .

Methylamine

Ethylamine

Iso-propylamine

Butylamine (n)

Isobutylamine

Amylamine

Diethylamine

Diproply amine

Di-isobutylamine .. .

Trimethylamine

Aniline 4)

Toluidine (ortho) . . .

Toluidine (meta)
Xylidine 1:3:4 ...

Monomethylaniline

Dimethylaniline

Dibenzylamine

Nitromethane 6) —

Nitroethane

Methylnitrate

Formula.

C6 H5CN

C8 H6 CH2 CN

C« H.4

(CH3

a n4 ^CN

CBHBN

Cb H4 NCH3 {a)

C5H10 NH

C9 H7 N

C2 Cl4

C2 Hb SH

CO. NH8 O. C2 H6

CO. NH2 O. C2 HB

CHS NH2

C2 H5 NH2
(CH3)2 CHNH2

C4H9NH2
(CH3)2 CHCH2 NH2

C5H„NH2
(C2 H5>2 NH
(C3H,)2NH
[(CH3)2CHCH2]2NH
(CH8)3N

C6 HSNH2

}

t.

L« M* JCH3 (0)

CH*{gS8»(m)(

(CH3-I
C6H3 ^CH3-3

(NHs-4

C6H5NHCH3
C6 H5N (CH3)2
(C6HB)s NH
CH3 N02
C2 H5 N02
CH3 N03

21

21

23°

21

20

22

21

21

22

23

60

21

21

20

21

21

22

21

22

22

24

20

20

20

20

D. C.

26.0
14.9
18.4
12.4
9.8
5.3
8.8
2.46
4.35
3.18
13.6
<!10.5
6.17
5.45
5.30
4.43
4.50
3.58
2.90
2.65
2.95
7.20
5.93

5.95

4.90

20

5.8

20

5.07

20

3.55

19

40.4

18

29.5

18

23.5

1 Drude found 26.0 for the D. C of benzonitrile at 21°C.

2 Drude found 15.0 for the D. C. of benzylcyanide at 19CC

3 Turner found 8.9 for quinoline.

4 The value 7.15 (at 21°) was found by Drude; and 7.22 fat 15°) by Ratz. Zeit phys.
Chem. 19, 94. (1896).

6 Thwing gives the value 56.36 at 15°.

374

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table IV — Continued.

Name.

Ethylnitrate

Propylnitrate

Isobutylnitrate

Isopropyluitrite

Phosphorus trichloride.,

Arsenic trichloride

Antimony trichloride (s)
Antimony trichloride (1)

Stannic chloride

Antimony pentachloride
Sulphur monochloride. .

Sulphur trioxide (s)

Sulphur trioxide (1)

Sulphury lchloride

Thionylchloride

Phosphorus oxychloride
Sulphur dioxide (1) ') .. .

Bromine (1)

Iodine (s)

Formula.

C2 H5 NOj

C3 H7 NOs
(CH3)2 CHCHs NO3
(CH3)s CH NOs

PCI3

AsCl3

SbCl3

SbCl3

SnCl4

SbCl5

S2 Cla
(S03)3
(S03)2

S03 Cl3

SOCI3

POCl3

SO,

Br

I.

IS

IS

19

19

22

'21

18

75

22

21.5

22

19

22

22

22

22

22

23

23

D. C.

18.3
13.9
11.7
11.5?
3.36
12.35
5.4
33 2
3.2
3.78
4.8
3.64
3.56
9.15
9.05
13.09
12.35
3.18
10.3?

The results obtained with the aliphatic nitriles the primary
amines, and the nitrates are represented graphically in Curves I,
IV and V of the accompanying figure. The dielectric constants
are plotted as ordinates, and the members of the homologous
series are noted as abscissse, a definite distance being chosen for
each addition of CH2. Curve II represents Drude's2 values for
the dielectric constants of the alcohols, while curve II (a) pre-
sents approximately the values obtained by Thwing,3 Nernst4
and Tereschin5 for the dielectric constants of the alcohols.
Curve III represents the values obtained by Drude for the di-
electric constants of the fatty acids. Hence in Curve I, R rep-

1 Linde gives the value 14.8 at 23". Coolidge gives the value 13.75 at 14.5.

2 Zeit. phys. Chem. 33, :?09. (1897).

3 Zeit. phys. Chem. 14, 286, (1894).
* Zeit. phys. Cham. 14, 622, (1894).

4 Wied. Ann. 36, 792, (1889).

SCHLUNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS. 375

K)0

90

80

70

60

50

40

30

20

10

1-

i

\

rr
\\

lU,

+4\

\ \

xx

\

\ x

m
K

>

*^

.X

fjurve I Nitri

- E,

I^.Alcoiols

Acids
A m i neS.
[slit Kites..

££^

*_

Ek

:^.

p feehlundL-

HR CH3R C^HsR G3H7R- C*HSR G^.R G6H,*R

376 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

resents the cyanogen group (CN) ; in Curves II and Ha, R
represents the hydroxyl group (OH) ; in Curve III, it repre-.
sents the carboxyl group (COOH) ; in Curve IV the amido
group (NH2) ; while in Curve V, R represents the (N03)
group. The value 16.2 for the dielectric constant of liquid am-
monia is taken from the work of Coolidge1 who measured its di-
electric constant at 14° C.

Discussion of Results.

The marked differences that exist between the physical prop-
erties of the first two members of any homologous series of com-
pounds are well exemplified by the great differences between the
dielectric constants of hydrocyanic acid and acetonitrile, of
water and methyl alcohol and of formic acid and acetic acid.
The difference in value between the dielectric constants of
liquid ammonia and liquid methylamine is not so marked
as in the other cases just mentioned; but it is highly
probable that the value found for methylamine is too high.
The curves show that in an homologous series the dielectric
constants decrease with increase of molecular weight. This
also holds for the aromatic amido compounds. Pyridine
(D. C, 12.4) and a-picoline (D. C, 9.8) also illustrate this
fact, as do also nitrobenzene [D. C, 35.0] and ortho-nitro-
toluene [D. C, 27.] 2 The primary amines have higher values
for their dielectric constants than the corresponding secondary
amines, and the values for the secondary amines are higher than
the tertiary, as is shown by the following examples :

Ethylamine, D. C. = 6.17.
Diethylamine, D. C. = 3.58.
Trimethylamine, D. C. = 2.95.

A further inspection of the values of the dielectric constants
of the several homologous series of liquid compounds investi-
gated by other observers will show that a decrease in the value
of the dielectric constant with increase of molecular weight is

i Wied. Ann. 69, 130, (1899).

1 This value was found by Turner. Zeit, phys. Chem. 35, 385, (1900).

SCHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 377

the general rule. Tereschin1 first pointed out this fact in con-
nection with the values he obtained for the dielectric constants
of a number of homologous esters of the aliphatic acids and
of benzoic acids. The values obtained by Tomaszewski, 2
however, for the dielectric constants of the homologues of
benzene, show that their dielectric constants increase with in-
crease of molecular weight. The dielectric constants of
the homologues of benzene and a number of aliphatic hy-
drocarbons have been determined by Landolt and Jahn,3
by Nernst,4 and by others. Some of these results are given
in the following table: The second column indicates the
values of the dielectric constants obtained by Tomaszewski,
the third column the values obtained by Landolt and Jahn,
while the last column gives the values obtained by Nernst.

Table V.

Substance.

Benzene

Toluene

Xylene (ortho)
Xylene (meta) .
Xylene (para) .

Mesitylene

Pseudocymene .
Cymene

Benzene

Toluene

Ethy lbenzene

Propylbenzene

Iso-propylbenzene .
Iso-butylbenzene . .

D. C. (Tomaszewski)

2.218
2.303

2.383

2.442

2.218
2.303

D. C (L.&J.)

Hexane.
Octane . .
Decane.

2.222

2.387

2.583

2.35

2.245

2.30

2.417

2.231

2.222

2.387
2.414
2.351
2.376
2.341

1.854
1.938
1.964

D. C. (Nernst).

2.255
2.355
2.567
2.372
2.251

2.415
2.249

2.255
2.355
2.424
2.380
2.368
2.347

1.88
1.949

i Wied. Ann. 36, p. 801, (1889).
* Wied. Ann. 33, p. 41, (1888).

J Zeit. phys. Chem. 10, 239, (IM1>-
4 Zeit. phys. Chem. 14, 622, (1894)

378 BULLETIN OF THE UNIVERSITY OF WISCONSIN.

From the results of Landolt and Jahn and those of Nern"t
it appears that the dielectric constants at first increase with in-
crease of molecular weight and subsequently they decrease as the
molecular weight increases. Tomaszewski's values show an in-
crease with increase of molecular weight throughout. Regard-
less of which series of values for the dielectric constants is cor-
rect, the results show that these hydrocarbons do not follow the
rule observed in connection with most other homologous series
of compounds, — namely, that an increase in molecular weight
is accompanied by a decrease in the value of the dielectric con-
stant.

The isomeric nitriles and alcohols have nearly the same di-
electric constants, the iso-compounds showing slightly higher
values. With the substituted ammonias the iso-compounds ex-
amined gave lower values than the normal compounds.

A comparison of the values of the dielectric constants of the
alcohols and nitriles by means of Curves I and II shows that
for oscillations of high frequency the nitriles have higher values
throughout than the corresponding alcohols. For oscillations of
low frequency the values for the dielectric constants of the
higher members of the alcohol series are nearly the same as the
values found for the corresponding nitriles with high frequency
oscillations. [Compare curves Ha and I.] Since the nitriles
show but slight absorption, their dielectric constants when ex-
amined by other methods where slower vibrations are used will
probably agree closely with the values found with Drude's ap-
paratus.

The marked effect of the presence of the cyanogen group in a
compound upon the value of its dielectric constant, is further il-
lustrated by comparing the dielectric constants of ethylacetate
(CH3 COOC2 H5) and ethylcyanacetate (CH2 CNC02 C2 H5),
for which Drude1 found the values 5.85 and 26.7 respectively.
The values 26.5 and 65.3 here found for ethylcyanide (C2 H5
GN), and ethylene cyanide (C2H4(CN)2), respectively also
exemplify this effect in a striking manner. Cyanogen itself,

i Zeit. phys. Chem. pp. 308, 310, (1897).

SCHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS.

379

however, has a very low dielectric constant, the value being in-
termediate between the values of chlorine and bromine. The
dielectric constant of liquid chlorine was determined by Linde,1
who found the value 1.93 at 14° C, and by Coolidge2, who ob-
tained the value 1.87 at 14.3° The values obtained for liquid
cyanogen (Table V)and bromine are 2.52 and 3.18, respec-
tively, at 23° C.

For the purpose of this discussion, the inorganic solvents
whose dielectric constants were measured, are divided into two
groups. One group contains the solvents whose dielectric con-
stants range from three to five, while the other group contains
the solvents whose dielectric constants range from nine to thirty-
three.

D. C. 3-5.

D. C 9-33.

Sulphur monochloride.

Arsenic trichloride.

Phosphorus trichloride.

Antimony trichloride.

Sulphur trioxide.

Phosphorus oxychloride.

Antimony pentachloride.

Sulphur dioxide.

Stannic chloride.

Sulphuryl chloride.

Bromine.

Thionyl chloride.

The ionizing power of these solvents has been investigated by
Kahlenberg and Lincoln3, and more fully by Walden.4 The
electrical conductivity measurements of Walden show that the
solvents with low dielectric constants yield solutions with tetra-
ethylammonium iodide, which do not conduct well enough to
make quantitative measurements profitable, while the other sol-
vents with relatively higher dielectric constants yield solutions
with the same salt and with other salts that conduct fairly well.
(See Table II.) Here then we have a good illustration of the
Nernst-Thomson rule, that the greater the dielectric constant of
a solvent the greater is its dissociating power. The following

i Wied. Ann. 56, 546, (1895).

8 Wied. Ann. 69, 123, (1899).

» Jour. phys. Chem. 3, 12, (1899).

* Berichte d. Deutsch. Chem. Gesel. 32, 2862, (1899). Zeit. anorg. Chem. 25, 209, (1900).

380

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

table gives the molecular conductivities at nearly corresponding
dilutions of tetraethylanimoniumiodide, [N(C2H5)4I], dis-
solved in the solvents noted. These results are taken from the
work of Walden to which reference has already been made. The
molecular conductivities in liquid S02 were made at zero de-
grees; in the other solvents the conductivities were made at 25°
C. The last column indicates the dielectric constants of the
solvents.

Table VI.

Solvent.

V.

Uv.

D. C.

POCI3

500
480
500
514
1811

33.45
54.26
19.59
25.50
126.9

13.9

AsCl3

12.35

SO- Cl2

9.15

SO Clo

9.05

S03

13.5

In connection with the results presented in this table it may
bo noted that there is no such parallelism between dielectric con-
stant and molecular conductivity as one would expect by the
Nernst-Thomson rule.

The high dielectric constant found for hydrocyanic acid is of
special interest from a theoretical point of view since by the
ISTernst-Thomson rule, this compound should possess extraordi-
nary dissociating power. The qualitative tests which Prof.
Kahlenberg and I have made, however, indicate that hydro-
cyanic acid does not possess dissociating power in a marked
degree. A number of salts which yield excellent conducting
solutions when dissolved in water, show comparatively feeble
conduction when dissolved in hydrocyanic acid. Here then is
a striking exception to the Nernst-Thomson rule. The quan-
titative measurements of the electrical conductivity of salts dis-
solved in hydrocyanic acid are now in progress in this labora-
tory and their publication will doubtless be awaited with con-
siderable interest.

This is the highest dilution which Walden examined.

SCHLUNDT — DIELECTRIC CONSTANTS OF PURE SOLVENTS.

381

The high dielectric constants of the nitriles and alcohols show
a marked contrast to the low dielectric constants of the substi-
tuted ammonias, which are of about the same order as the di-
electric constant of chloroform [D. C. = 5.0], and ether
[D. C. = 4.4], Now the ionizing power of chloroform and
ether is exceedingly small, which fact is in perfect accord with
the Nernst-Thonison rule. But Prof. Kahlenberg1 finds that
the primary amines, which have values for their dielectric con-
stants approximately the same as those of chloroform and
ether, still yield solutions that conduct fairly well. Here then
we have a number of exceptions to the Nernst-Thomson rule
opposite in kind to the case of solutions in hydrocyanic acid ;
namely, solvents with relatively very low dielectric constants
that still possess moderate ionizing power.

The electrical conductivity of solutions in nitriles has been
studied by Dutoit and Friderich. 2 Their results show that the
conductivity of salts dissolved in the homclogues, acetonitrile,
propionitrile, and butyronitrile decreases in the order in which
the solvents are named. Their dielectric constants also de-
crease in the same order ; thus supporting the ISTernst-Thomson
rule. This relation between the dielectric constant and electri-
cal conductivity is illustrated by the following table, in which
U stands for the molecular conductivity at 25° C, and V, the
number of liters in which one gram molecule of silver nitratfo
is dissolved.

Table VII.

Solvent.

V.

U.

D. C. at 21".

64.0
63.7
75.6

103.7
46.0
25.4

36.4

26.5

20.3

Propionitrile and benzonitrile have about the same dielectric
constant, but the molecular conductivities of silver nitrate dis-

1 Jonr. phys. Chem. June, 1901.

4 Bull. Chem. Soc. Paris [3] 19, 321, (1898).

382

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

solved in these nitriles are quite different, as a comparison of
the results in the followng table shows. The molecular con-
ductivities of silver nitrate in benzonitrile are taken from the
work of Lincoln1 while those for the propionitrile are taken
from the work of Dutoit and Friderich.2

Table VIII.

Benzonitrile.

Propionitrile.

V.

V at 25<>C.

V.

U at 25CC.

24 06
58.98
83.92

7.66
11.19
13.41

32.0
63.7

34.9

46.0

The molecular conductivities of silver nitrate dissolved in
pyridine and in butyronitrile furnish another interesting com-
parison.

Table IX.

Solvent.

Butyronitrile 3) .

Pyridine 4) .

V.

U. at25»C.

75.6

25.4

150.4

32.1

60.9

30.17

140.7

36.21

D. C.

20.3

12.4

While Table VII shows that the Nernst-Thomson rule holds
for the three members of the same homologous series, Table
VIII demonstrates that chemically analogous substances having
about the same dielectric constants may nevertheless yield solu-
tions (containing the same solute) with very different electrical
conductivities. Table IX shows conclusively that a pyridine
solution of silver nitrate conducts better than a corresponding

1 1. c. pp. 422, 423.
2 1. c. pp. 300, 331.
8 1. c. pp. 42A 42 i.
* 1. c pp. 330, 331.

8CHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 383

one in butyronitrile, notwithstanding the fact that the dielec-
tric constant of pyridine is only 61$ of that of butyronitrile.
Here, then, we have two further exceptions to the jSTernst-Thom-
son rule. But in these eases the exceptions might be explained
on the basis of the theory of electrolytic dissociation. Since
the molecular conductivity depends upon the speed of the ions
as well as the number of ions, i. e., the degree of dissociation,
it might be argued that the magnitude of the conductivity at
corresponding dilutions, giving as it does the combined effect
of these two factors, is therefore not a safe criterion for deter-
mining the dissociating power of a solvent, although compari-
sons of this kind are frequently made in support of the rule.
For example, in the case of the molecular conductivities of sil-
ver nitrate in pyridine and butyronitrile, if it be assumed that
the speed of the ions in pyridine is materially greater than in
butyronitrile, then the molecular conductivity in pyridine
may be greater than in butyronitrile, even though the
number of dissociated molecules be somewhat less, as is re-
quired if we assume the ISTernst-Thomson rule to hold. In
the cases cited in Tables VIII and IX the degree of dissoci-
ation could not be computed from the electrical conductiv-
ity measurements, as no maximum value for the molecular
conductivity was obtained. And since, in the case of pyri-
dine and benzonitrile solutions, Werner1 found normal molec-
ular weights for silver nitrate by boiling-point determinations,
this means of calculating the degree of dissociation could
of course not be applied.2 Hence on the basis of the experi-
mental evidence which can be applied in these cases, they must
be considered exceptions to the Nernst-Thomson rule.

In this connection it may be well to note a few other excep-
tions to the Nernst-Thomson rule. The cryoscopic and electri-
cal conductivity measurements by Zanninovich-Tessarin3 show
that potassium chloride dissolved in formic acid is highly disso-
ciated, as one would expect from the high dielectric constant

1 Zeit. anorg. Chem. 15, 1, (1897).

2 Compare Kahlenberg, Jour. Phys. Chem. 3, pp. 397-399 on this point. .
» Zeit. phys. Chem. 19, 251, (1896) .

384

BULLETIN OF THE UNIVERSITY OF WISCONSIN.

[D. C. = 62] of the latter. But solutions of hydrochloric acid
in this solvent show but slight dissociation. Nernst1 in refer-
ring to this case assumes that some specific influence of the sol-
vent comes into play, probably the association of the ions with
the molecules of the solvent.

Another exception is noted by Franklin and Kraus2 in their
researches on the electrical conductivity of liquid ammonia solu-
tions. Mercuric cyanide, according to Ostwald,3 is not at all
dissociated in water, but Franklin and Kraus find that in ammo-
nia it forms a solution which possesses a distinct conductivity.
Again, the phenols yield good conducting solutions in ammonia,
while in water they form solutions which have relatively low
conductivity. The following table illustrates this point. It
gives the molecular conductivities of orthonitro-phenol in water
at 18° C. and in liquid ammonia at — 38° C.

Table X.

Watee 4)

Liquid Ammonia 5)

V.

U.

V.

U.

250

4.09

366.2

82.76

500

5.14

2299.0

148.3

1000

7.24

10380.0

203.9

2000

D 00 =

r355

10.30

63860.0

240.1

Choral and ethyl acetate, according to Drade,6 have the values
6.67 and 5.85, respectively, for their dielectric constants. The
former, according to Kahlenberg and Lincoln,7 yields solutions
with ferric chloride which show no appreciable conduction,
while the latter yields solutions with it, which show a distinct
conductivity.

From the work of the same investigators we see

1 " TheoretLsehe Chemie," p. 365. (Dritte AufHageJ.

2 Am Chem. Journal, 23, 207, (1900 .>.

3 Grundlinien der anorg. Chem. p. 657.

4 Bader: Zeit. phys. Chem. 6, p. 206, (1890).

5 Am. Chem. Jour. 23, p. 29."), (1900).
• Zeit. phys. Chem. 23, p. 309, (1897).
7 Jour. Phys. Chem. 3, 12, (1899).

BCHLUNDT DIELECTRIC CONSTANTS OF PURE SOLVENTS.

385

that ferric chloride does not yield conducting solutions with
ethylene chloride [D. C. = 11.31], but it yields solutions with
several other solvents having dielectric constants of about the
same order or even less, which have very distinct conductivity.
Here, then, we have a number of additional exceptions to the
Nernst-Thomson rule.

The exceptions to the Nernst-Thomson rule noted above in
connection with liquid ammonia solutions, however, do not indi-
cate the general behavior of ammonia solutions of the common
salts. While it is true that ammonia solutions for the most
part show greater molecular conductivity than aqueous solu-
tions of the same concentration, yet the degree of dissociation is
as a rule less than that of the corresponding aqueous solutions.
This point is well illustrated by the following table taken from
the work of Franklin and Kraus.2 It shows the dilution at
which dissociation reaches 90$ in the two solvents.

Table XI.

Solute.

Water at 18'C.

Ammonia at — 38°.

20.0
20.0
25 0
32.0
33.0
25.0
40.0

2000

4000

5000

2500

4000

5000

1500

Carrara's scheme for comparing the dissociating power by cal-
culating the dilution for the same solute in which a definite de-
gree of dissociation is obtained by electrical conductivity meas-
urements, seems an excellent one to apply in this connection to
solvents which yield good conducting solutions. In the follow-
ing table the volumes of the solvents enumerated correspond to

i Jahn and Moller: Zeit. phys. Chem. 13, 335, (1894),
3 Am. Chem. Jour. 23, 297, (1900).

386

BULLETIN OF THE UNIVERSITY OP WISCONSIN.

a degree of dissociation equal to 76$, according to Carrara,1 the
solute being tri-ethylsulphine iodide, (C2H5)3 SI. Under V
the volume in liters is given in which one gram molecule of sub-
stance is dissolved. The dielectric constants in the second col-
umn are those found by Drude, while those in the third col-
umn are taken from the results of Nernst, Tereschin, and
Thwing. According to the Nernst-Thomson rule the volumes
should increase' as the D. C. decreases.

Table XII.

Solvent.

Water

Methyl alcohol
Ethyl alcohol. .
Propyl alcohol
Allyl alcohol . . .
Acetone

.

D. C.

D. C.

81.0

80

32.5

32.6

21.7

25.8

12.3

22.8

20.6

21.6

20.7

21.8

Volume.

39.6

504.0

1015.0

89.0
498.0

An inspection of the table shows that with one exception there
is a general parallelism between dissociating power and dielec-
tric constant, but the example of allyl alcohol is certainly a
striking exception.

Table XIII gives the approximate volumes of various sol-
vents in liters in which a gram molecule of potassium iodide is
dissociated to the extent of 75$.

Table XIII.

Solvent.

D. C.

Volume.

80.

32.5

22.0

20.5

12.4

0.4
29

Methyl alcohol

400

128

1100

In this case we have another exception in liquid ammonia
and acetone.

J Zeit. Elektrochem. 4, 475, (1897-93).

8CHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 387

When the exceptions noted are considered collectively it be-
comes evident that the Nernst-Thomson rule must relinquish a
good share of the prestige it has hitherto enjoyed. While it is
true that in these pages a number of new examples supporting
the rule have been given, yet the exceptions noted are of a kind
not to be underrated. The rule as it now stands is no more gen-
eral than the hypothesis of Briihl which attempts to account for
the dissociating power of solvents by assuming spare valences
to exist, or the parallelism that Dutoit and Aston claim between
dissociating power and polymerization of the molecules of the
solvent. These theories have been shown to be inadequate by
Lincoln,1 Euler,2 and Kahlenberg.3 These investigators cite
striking exceptions to these theories and therefore hold them
untenable. Hence until we have some experimental evidence
in place of the speculative "specific influences" which are said
to exist and to account for exceptions to the Nernst-Thomson
rule, it must be considered inadequate in accounting for the dis-
sociating power of solvents by virtue of their high specific in-
ductive capacity.

Relation behveen the dielectric constant and the latent heat
of evaporation. — Since Louguinine4 and Kahlenberg5 have re-
cently determined the latent heat of evaporation of a number
of nitriles it seemed of interest to see how closely Obach's law,
that the ratio between the dielectric constant and the latent heat
of evaporation is approximately a constant for an homologous
series, holds for the nitriles. The following table gives the
latent heats of evaporation, the dielectric constants, and in the
column headed -57^- the ratio of the heat of evaporation to the
dielectric constant :

1 Jour. Phys. Chem. 3, 457, (1899).
a Zeit. phys. Chem. 28, 619, (1899).
3 Jour. Phys. Chem. June (1901).
* Compt. Rend., 132, 88, (1901).
'Jour. Phys. Chem. 5, 215, (1901)

388

BULLETIN OP THE UNIVERSITY OF WISCONSIN.

Table XIV.

Substance.

Acetonitrile .
Propionitrile
Butyronitrile
Valeronitrile
Capronitrile .

L. H.

D. C.

173.6

36.4

134.4

26.5

115 25

20.3

95.96

17.4

88.09

15.5

L. H.

D. C.

4.77
5.07
5.48
5.51
5.68

The ratios can hardly be said to be constant although the
values obtained for the nitriles show as close an agreement as
the values Obach had in hand when he indicated the relation
between dielectric constant and heat of vaporization, as will
appear from the following table which has been selected for

comparison

.i

Table XV.

Substance.

Methyl formate —

Ethyl formate

Propyl formate

Iso-butyl formate.
Amyl formate (iso)

L. H.

D. C.

105.8

9 9

91.9

9.1

83.7

9.0

75.7

8.4

71.0

7.7

Ratio.

10.7

10.1

9.3

9.0

9.2

Conclusion.

The principal points in the foregoing presentation may be
summarized in the following general statements :

1. The values of the dielectric constants for the homologous
series of compounds examined decrease with increase of molec-
ular weight.

2. The introduction of the cyanogen group in a compound
causes a marked increase in the value of the dielectric constant.
In this respect the cyanogen radical produces a greater effect
than all other radicals which have hitherto been systematically
studied.

1 Phil. Mag. 3«, p. J17, (1891).

8CHLUNDT — DIELECTRIC CONSTANTS OP PURE SOLVENTS. 389

3. The cyanogen (CN), amido (NH)2, or nitric acii
(N03) radicals when present in compounds do not cause anom-
alous absorption as Drude found for the hydroxy 1 (OH) group.

4. A number of new examples have been given which follow
the Nernst-Thomson rule.

5. Some striking exceptions to the !NTernst-Thomson rule have
been pointed out from which it has been argued that the rule
is inadequate. The exceptions indicate that the nature of the
solvent as well as the dissolved substance are of prime impor-
tance in determining whether a solution will conduct electricity.

6. Obach's law holds only approximately for the nitriles.

This investigation was made in the Laboratory of Physical
Chemistry of the University of Wisconsin. It was undertaken
at the suggestion of Professor Kahlenberg and carried on un-
der his supervision. As before stated, I am indebted to him
for placing at my disposal many of the solvents used for these
measurements, and I am under many obligations to him for his
helpful suggestions and for the active interest he has always
shown in my work ; and I am glad to have this opportunity of
acknowledging it.

A portion of the results of the work on the nitriles has previ-
ously been published in a preliminary article in the Journal of
Physical Chemistry 5, 157, (1901). For the sake of complete-
ness the results have also been incorporated in the present
paper.

Laboratory of Physical Chemistry,
University of Wisconsin,

Madison, May, 1901.

INDEX TO VOLUME 2.

Absorption method of investigation of

epithelium, 239.
Action of solutions on the sense of taste

(.title of paper >, 1
Air-space, 154.
Alcohol, influence of, 115.
Alkaloids, taste of, 27.
Allen, Grant, cited on diet, 107.
" Americanitis," 172.
Amphibia, nerves of, 232.
Anderson, cited on mechanism of nervous

system, 51.
Angell and Thompson, cited on effect of

mental activity on circulation, 48.

, cited on effect of noise, 165.

, cited on mental troubles, 171.

Anions, 6.

Anomalous dispersion of cyanin (title of

paper), 217.

, Bibliography, 288.

Aqueous solutions, nature of, 4.
Aristotle, cited on play, 160
Arnold, cited on stomata, 237, 210, 241.
Arrhenius, cited on boiling and freezing-
points, 334, 338.
, cited on relation of dissociation and

conductivity, 317.
, cited on theory of electrolytic disso-
ciation, 3, 5, 299etseq.
Arteries of Necturus, 211.
Aspects of mental economy (title of paper) ,

33.
Aston, cited on " dissociation power " of

solvents, 343.
Atkinson, cited on cost of dietaries, 149.

, cited on dietaries, 93, 95, 101, 137.

Atwater, cited on alcohol as food, 116,

123.

.cited on cost of food, 147, 150.

, cited on dietaries, 92, et seq.

, cited on food analyses, 84, et seq.

Austin, R. M., Kahlenberg, L., and, cited

on physiological aspect of dissociation,

339.
Avogadro, cited on gases, 5.

Bach, cited on legibility of letters, 183.

Bader, cited on conductivities of phenols
in water, 384.

Bain, cited on individuality, 139.

Baldwin, cited on emotions, 61.

, cited on influence of associates, 197.

, cited on influence of body on mind,

174.

, cited on mental troubles, 171.

Barnard, cited on seating, 185.

Bateson, cited on variation, 139.

Battle Creek Sanitarium, 149.

Beard, cited on amount of sleep, 164.

, cited on fatigue, 62.

, cited on toxic products of nervous ac-
tion, 49.

Beer, cited on light waves, 259.

Binet, A., and Henri V., cited on effect
of intellectual activity, 48.

, cited on fatigue, 5V.

Bird, Uolding, cited on analyses of stom-
ach fluids, 140.

Bishop, Emily, cited on Delsartean phil-
osophy, 174.

Body and mind, relation of, 44.

Bohm, cited on stomata, 237.

Boiling-point determinations, 320.

BOrnstein, Landolt and, cited on elec-
trical conductivity of solutions, 15.

Brain, effect of mental activity on, 47.

, of Necturus,2Z] .

, , Bibliography, 234.

Briot, cited on theory of light, 260.

Brocca, cited on localization of function,
190.

Bruhl, cited on " dissociating " power of
solvents, 343, 344, 387.

Bryan, cited on fatigue, 51, 55.

Brunsen, cited on current density, 345.

Burgerstein, cited on fatigue, 58.

, cited on study time, 191.

Burk, cited on emotions, 61.

, cited on exercise, 156.

— , cited on motor control, 57.

, cited on need of motor activity, 158.

Burnham, cited on air space per individ-
ual, 154.

, cited on legibility of letters, 183.

, cited on oxygen supply, 153.

, cited on seating, 186.

Call, Annie Payson, cited on Delsartean
philosophy, 174.

Carpenter, cited on hygiene, 68.

Carrara, cited ©n comparison of dissociat-
ing power, 385, 386.

Castoro, Nicolo, cited . on non-aqueous
solutions, 303.

Cat, epithelium of the peritoneal cavity
of,2.J5.

, Bibliography, 145-6.

Cathions, 6.

, taste of, 22.

Cattel, cited on legibility of letters, 184.

Cauchy, cited on light waves, 259.

Chambers and Frazer, cited on freezing-
points, 318.

Chambers, Jones and, cited on freezing-
points, 314, 318, 319.

Chaumont, de, cited on air space per indi-
vidual, 154.

Chelonia, olfactory lobes of, 228.

Christiansen, cited on anomalous disper-
sion by fuchsin, 250, 251, 261.

Christoffel, cited on Cauchy's assump-
tion, 2C0.

Church, cited on food analyses, 84, 86.

, cited on liquors, 115.

, cited on tea, coffee and cocoa, 108.

, cited on wheat as food, 98.

392

INDEX TO VOL. 2.

Clark, J F., cited cm physiological, as-
pect of dissociation, 839.

Classen, cited on electrolytic quantitative
analysis, 345.

Clausius, cited on free ions, 299.

Clouston, cited on American mental
strain, 172.

Cocoa, analyses of, 109.

Coffee, analyses of, 109.

Cohn, cited on sight, 179, et seq.

Cohnheim, cited on stomata, 241.

Collins, cited on moral degeneracy, 63.

Colloidal Solutions, 28.

Condiments, 107.

Conductivity determination, 305.

Contributions from the Anatomical Lab-
oratory of the University of Wisconsin
(title of paper), 199.

Cookery, methods of, 12S.

, philosophy of, 126.

Coolidge, cited on dielectric constant of
liquid ammonia, 358, 376.

, , of liquid chlorine, 379.

, , of liquid sulphur dioxide, 371,

374.

, cited on method of measuring dielec-
tric constants , 3t>3.

Cooper, cited on punishment, 68.

Cornish, cited on animal emotions, 61.

Cowles, cited on amount oi sleep, 164.

, cited on fatigue, 62.

, cited on toxic products of nervous ac-
tion, 49.

Crompton, cited on dissociation hypothe-
sis 339.

/cited on explanation of Van't Hoff's

' theory of solutions, 341.

Crossed prism method, 277.

Curtis, cited on application, 192.

, cited on exercise, 156.

, cited on fatigue, 75.

Cyanin, Anomalous dispersion of, 247.

Dancing, 161.

Daewin, cited on emotions, 171.

, cited on mind and body, 45.

, cited on variation, 139.

Delsartean philosophy, 174.

Dewey, cited on diseases of the eyes, 182.

Dielectric constants of pure solvents,

353.
Dietaries, 92. 101.

, expense of, 145.

Dieterici, C, cited on vapor tension, 314,

319. 347, 348.
Dipnoans, brain of, 229.
Dissociation, electrolytic, Arrhenius'

theory of, 3.
Dogiel, Schwetgger-Seidel and, cited
on injection, 239.

, cited on stomata, 237.

Dogs, effect of alcohol on, 122.
Donaldson, cited on application, 193.

, cited on daily fatigue, 195.

, cited on effect of noise, 165.

, cited on localization of function, 190.

, cited on motor control, 57.

, cited on nerve cells, 46, 50.

Dreser, H., cited on the pharmacology of

mercury, 25.
Dressler, cited on fatigue, 57, 62.
Drude, cited on dielectric constants, 356,

358, 364, 365, 373, 384.
, cited on formula for dielectric con-
stants, 360.
, method of measuring dielectric con-
stants, 358, 363.

Drummond, cited on emotions, 61.

, cited on mind and body, 45.

Dctoit, cited on " dissociation power"
of solvents, 313.

, cited on parallelism between dissociat-
ing power and polymerization, 3*7.

Dutoit and Friderick, cited on ionizing
power of acetonitrile, 357, 381, 382.

, cited on non-aqueous solutions, 302.

Dybkowsky, cited on injection method,
239.

— -, cited on stomata, 237.

Ecker, cited on nerves of frosr, 232.

Eggers, Harry, cited on sulphur mono-
chloride, 370.

Electrolytes, 4.

, taste of solutions of, 13.

Electrolytic dissociation, 297.

Ellenberger, cited on openings in epithe-
lium, 243.

, cited on stomata, 237, 240.

Elliot, cited on study hours, 189.

Epithelium of the lung, 203.

, of the peritoneal cavity of the cat,

235.

, , Bibliography, 245-6.

Eulenbep.g, cited on legibility of letters,
183.

Ecler, cited on non-aqueous solutions,
302. . 00_

, cited on theories of dissociation, 387,

Exercise, 156.

Experimentation, method of, on action
of solutions on sense of taste, 11.

Eye, diseases of, 179.

Fatigue, neural, 50, et seq.

, , emotional effects, 60.

, , intellectual effects, 55.

, — ■ — , motor effects, 50.

Ferrier, cited on localization of function,
190.

Fibers, elastic, of lung, 206.

, muscle, of lung, 206.

, nerve, of lung, 207.

Fischer, cited on nerves of Siredon, 232.

Fish, cited on brain of Urodelei, 227, 232.

Fiske, cited on mind and body, 45.

Flechsig, cited on application, 192.

, cited on exercise, 156.

, cited on localization of function, 190.

, cited on motor control, 57.

Foods, analysis of, 84.

, as producers of nervous energy, 73.

, classification of, 77.

, heat producing, 100

, statistical studies of, 78.

FoifSTER, cited on dietaries, 92.

Franklin and Kraus, cited on conduc-
tivities-. 332.

, cited on ionizing power of liquid am-
monia, 357, 384, 385.

, cited ou non-aqueous solutions, 303.

Frazer, Chambers and, cited on freezing-
points, 3]>.

Freezing-point determinations, 306, 311.

Fresnel, cited on theory of dispersion,
258.

Friderich, Dutoit and, cited on ion-
izing power of acetonitrile, 357, 381, 382.

, cited on non-aqueous solutions, 302.

Froebel, cited on play, 16U

Frog, lung of, 204.

INDEX TO VOL. 2.

393

Gage, Mrs., cited on nerves of Diemyciy-

lus, 232.
Galton, cited on individuality, 139.
Gaule, cited on influence of alcohol, 118,

123.
Gebhardt, cited on method of preparing

phosphorus oxychloride, 370.
Germann, cited on aesthesiometric test,

57.
Gilbert, cited on fatigue, 57.
Gladstone, cited on amount of sleep, 164.
Glazebrook, cited on reaction between

matter and ether, 264.
Goddard, cited on faith cure, 173.
Goodwin and Thompson, cited on dielec-
tric constant of liquid ammonia, 342,

358.
Gorski, St. v., Lasctnski, St. v. and,

cited on ionizing power of pyridine, 357.
Griesbach, cited on aesthesiometric test

for fatigue, 57.
Groos, cited on recreation, 161.
GrjLicii, cited on recreation, 151.

Haddon, cited on emotions, 61.

Hall, cited on emotions, 61.

Hall, Roy D., acknowledgments to, 305.

Hall, Roy D., Kahlenberg, Louis,
Koch, Arthur A., and, Theory of elec-
trolytic dissociation as viewed in the
light of facts recently ascertained (title
of paper), 297.

Halleck, cited on motor control, 57.

Hancock, cited on motorability, 176.

Harley, on alcoholic action on nerves,
117.

Hartwell, cited on motor control, 57.

Hayem, cited on analysis of stomach fluids,
140.

Heaviside, cited on Helmholtz's equa-
tions, 267.

Helmholtz, cited on relation of matter
and ether, 262, 263, 264, 266.

Henri, V., and Binet, A., cited on effect
of intellectual activity, 48.

, cited on fatigue, 58.

Hittorf, cited on variation of migration
numbers, 317, 345.

Hitzig, xjited on localization of function,
190.

Hodge, cited on effect of activity on cells,
49, 50.

, cited on effect of alcohol, 121, 123.

, cited on effect of lack of sleep in ani-
mals, 163.

, cited on fatigue, 169.

Hoff, van't, cited on osmotic pressure,
349.

, cited on theory of solutions, 3, 5, 299,

et seq.

Hoffding, cited on variation, 139.

Hoffman, cited on food analyses, 89.

Holborn, Kohlrausch and, cited on con-
ductivities, 309.

Holmes, cited on study time, 191.

Horsley, cited on localization of func-
tion, 190.

Hours of study, 189.

Hoeven, .f. van der, cited on Meno-
branchua, 20!.

Hughes, cited on recreation, 161.

Hughlings-Jackson, cited on mechanism
of nervous system, 54, 55.

Hurion, cited on dispersion by iodine
vapors, 250.

Hygiene, cerebral, 64.

Impregnation method of investigation,

240.
Injection method of investigation, 239.
Innes, cited on non-aqueous solutions, 303.
Interferometer method, 279.
Ions, 6.

, taste of, 13.

Ireland, cited on motor control, 57.

J.win, cited on law of mass action, 346.
Jahn, Landolt and, cited on dielectric

constants of homologues of benzene, 377,

378.
Jahn and Miller, cited on solutions of

ferric chloride, 385.
James, cited on American mental strain,

172.

, cited on diseases of the eye, 180.

, cited on fatigue, 56.

, cited on influence of body on mind,

174.

, cited on mind and body, 45.

Javal, cited on legibility of letters, 183.
Johnson, G. E., cited on recreation, 160,

161.
Jones, H. C, cited on ions, 340.
.Jones and Chambers, cited on freezing-
points, 314, 318, 319.
Jordan, cited on cost of board, 149, 150.

, cited on dietaries. 96.

, cited on food analyses, 84.

Jurgensen, cited on dietaries, 92.

Kahlenberg, Louis, acknowledgments to,
358, 389.

, action of solutions on the sense of

taste (title of paper), 1.

, cited on calculation of degree of dis-
sociation, 383.

, cited on conductivities of solutions,

381.

, cited on dissociating power of hydro-
cyanic acid, 380.

, cited on iodine, 371.

, cited on latent heat of evaporation,

387.

, cited on non-aqueous solutions, 303,

■ 304.

— , cited on physiological aspect of dis-
sociation, 339.

, cited on substituted ammonias as

conductors, 358.

, cited on theories of dissociation, 387.

Kahlenberg, L , and Austin, R. M.,
cited on physiological aspect of dissocia-
tion, 339.

Kahlenberg, Louis, Koch, Arthur A.,
and Hall, Roy D., theory of electrolytic
dissociation as viewed in the light of
facts recently ascertained (title of paper),
297.

Kahlenberg and Lincoln, cited
ductivity of aqueous solutions,
313, 344.

— — , cited on ionizing power of certain
solvents, 379, 381.

, cited on non-aqueous, solutions 302.

Kahlenberg and Schreiner, cited on
freezing-points, 335.

Keating, cited on burden of school work,
188.

Kellogg, J. H., cited on dietaries, 96, 99,
101, 103, 105.

, cited on food analyses, 84.

, cited on nuts as food, 88.

on con-
338, 342,

394

INDEX TO VOL. 2.

Kellogg, J. H., cited on stomach fluids, 140.

, cited on study hours, 189.

Kelvin, Lord, cited on absorption line of
sodium vapors, 262. _

Ketteler, cited on index of refraction,
261.

, cited on method of studying disper-
sion, 253.

, cited on reaction between matter and

ether, 264, et seq.

Ketteler and Helmholz, dispersion for-
mula, 257, 267, 268.

Kingsley, cited on nerves of Ampliiuema,
232.

Kipling, cited on animal emotions, 01.

Klein, cited on stomata, 237, 238, 240.

Klein and Noble Smith, cited on stoma-
ta, 237.

Kleeker, de, cited on method of studying
dispersion, 253.

Koch, Arthur A., acknowledgments to,
305, 320.

Koch, Arthur A., Kahlenberges, Louis,
and Hall, Roy D., Theory, of electro-
lytic dissociation as viewed in the light
of facts recently ascertained (.title of
paperi, 297.

Kohlradsch, cite 1 on conductivity of
aqueous solutions, 338.

, cited on ionizing power of water, 357.

, cited on pure water, 19.

Kohlrausch and Holborn, cited on con-
ductivities, 309.

Konowalow, D., cited on conductivities
of solvents, 351.

Kotelman, cited on amount of sleep, 164.

, cited on study time, 19 i.

Krannhals, cited on conductivity of salts,
305.

Kraepelin, cited on burden of school
work, 188.

, cited on effect of activity on brain, 43.

, cited on fatigue, 51, 58.

, cited on study time, 191.

Kraus, Franklin and, cited on conduc-
tivities, 342.

, cited on ionizing power of liquid am-
monia, 357, 384, 385.

, cited an non-aqueous solutions, 303.

Keause, cited on stomata, 239.

Kundt, cited on anomalous dispersion of
fuchsin, 251, 252, 261.

, cited on dependence of dispersion on

absorption, 258.

IjADD, cited on chemical composition of
cell nuclei, 47.

Ladenburg, cited on method of purifica-
tion of pyridine, 366

Landolt and Bornstein, cited on electri-
cal conductivity of solutions, 15.

Landolt and Jahn, cited on dielectric con-
stants of homologues of benzene, 377.

Landsbergee and Biltz, cited on molec-
ular weight of salts, 332.

Lascynski, St. v., cited on ionizing power
of ace ton 3, 357.

LASCYNSKI, St. V., AND GORSKI, St. V.,

cited on ionizing power of pyridine, 357.
Lea, J., cited on method of preparing

methyl nitrate, 368.
Le Conte, cited on emotions, 61.

, cited on sight, 179.

Lee, Vernon, and Thompson, C. A., cited

on influence of associates, 197.
, cited on influence of body on mind,

174.

Le Roux, cited on dispersion by iodine va-
pors, 250.

Leuba, cited on aesthesiometric test, 57.

Light, dispersion of, 247.

, Bibliography, 288.

Lincoln, cited on conductivity of salts,
342.

, cited on ionizing power of benzo-ni-

trile, 357, 382.

, cited on non- aqueous solutions, 302,

, cited on seat ng, 185.

, cited on theories of dissociation, 387.

Lincoln, Kaiilenberg and, cited on
conductivity of aqueous solutions, 338,
342, et seq.

, cited on ironizing power of certain

solvents, 279, 384.

, cited on non-aqueous solutions, 302.

Linde, cited on dielectric constant of
liquid chlorine, 379.

, cited on dielectric constant of liquid

sulphur dioxide, 371, 374.

Locke, cited on play, 160.

Lombard, cited on daily fatigue, 195.

, cited on effect of activity on brain, 46.

, cited on effect of noise, 165.

, cited on fatigue, 51, 53, 55.

Lombrosa, cited on moral degeneracy, 63.

Lommel, cited on reaction between mat-
ter and ether, 264.

Long, cited on inversion of sugar by salts,
16, 17.

Loomis, cited on freezing-points, 319.

Lotze, cited on individuality, 139.

, cited on mind and body, 45.

Louguinine, cited on latent heat of evap-
oration, 387.

Loven, Schwalbe and, cited on taste-
bulbs, 8.

Ludwig, cited on artificial respiration,

239.

Ludwig and Schweigger-Seidel, cited
on stomata, 237, 240.

Lundquist, cited on polarization of re-
flected light, 254.

Lung of Necturus, 203, et seq.

, Bibliography, 210.

McCullagh, cited on theory of dispersion,

258.
Maggiora, cited on effect of activity on

brain, 46.

, cited on fatigue, 51.

Magnusson, Carl Edward, anomalous

dispersion of cyauin (title of paper), 247
Marble, cited on seating, ^5.
Marshall, cited on emotions, 61.
Maetin, cited on air space per individual,

154.

, cited on effect of alcohol, 121.

, cited on hygiene, b5.

, cited on organs of taste, 8.

Maudsley, cited on effect of alcohol, 119.
.Meath, Earl of, cited on recreation, 161.
Mental Economy, aspects of, 33.
Mercier, cited uu control of motion by

brain, 54.
— , cited on effect of alcohol, 119.

, cited on insanity, 62.

, cited on moral degeneracy, 63.

, cited on motor control, 57.

Mebkel, cited ou polarization of reflected

light, 254.
Method of conductivity determination,

305.
Method of experiment on dispersion of

cyauin, 268.

INDEX TO VOL. 2.

395

Meyer, cited on seating, 186.

Meyer, A. W., cited on the epithelium of

♦the peritoneal cavity of the cat, 202.

Meyer, Lothar, cited on osmotic pres-
sure, 349. .

Meynert, cited on localization of func-

p tion, 190.

Miller, W. S., Contributions from the
Anatomatical Laboratory of the Univer-
sity of Wisconsin (title of paper), 199.

Mills, cited on amount of sleep, 164.

, cited on toxic products of nervous

action, 49.

Mind and body, relation of, 44.

Moleschott, cited on dietaries, 92.

Moller, Jahn and, cited on solutions of
ferric chloride, 385.

Morgan, cited on emotions, 61.

Morrison, cited on moral degeneracy, 63.

, cited on ventilation, 156. ,

Mosso, Angelo, cited ou effect of activity
on brain, 46, 48, 49.

, cited on fatigue, 51, 52, 53, 55, 62, 75.

Munk, cited on localization of function,
190.

Murphy, Stevenson and, cited on nutri-
tion and dietaries, 68. 80, 98.

Mcscatello, cited on classification of
cells, 236.

, cited on endotheliel cells, 243.

, cited on stomata, 211.

Napoleon, cited on amount of sleep, 164.
Necturus maculatus, 201, etseq.
Nerust, cited on conductivity of solutions,

342.
, cited on dielectric constants, 355, et

seq.
, cited on dissociation of hydrochloric

acid solutions, iJ84.

, cited on dissociation of water, 341.

■ , cited on properties of salt solutions,

338.
, cited on theory of E. M. F. of galvanic

cell, 346.
Nernst-Thomson rule, 380, et seq.
Newman, cited on theory of dispersion,

258.
Neutral substances, 4.
Newsholme, cited on exercise, 156, 159.

, cited on study time, 191.

Newt, lung of, 204.

Newton, cited on ordinary dispersion,

252.
Noise, effect of , on sleep, 163.
Non-electrolytes, 4.
Noyes, Arthur A., cited on reviews of

references, 339.

Obach, cited on law of ratio between di-
electric constant and latent heat of evap-
oration, 387, 388.

Ochsner, H. W., cited on lung of Nec-
turus, 202.

On the dielectric constants of pure sol-
vents (title of paper;, 353.

Oppenheim, cited on burden of school
work, 188.

, cited on diseases of eyes, 182.

, cited on emotions, 61.

, cited on motor control, 57.

, cited on need of motor activity, 158.

Osborn, cited on brain of Necturus, 229,
230, 232.

O'Shea, M. V., Aspects of mental economy
(title of paper;, 33.

O'Shea, M. V., cited on activities of chil-
dren, 176.

, cited on diseases of the eye, 180.

, cited on Delsartean philosophy, 174.

, cited on fatigue, 57.

, cited on recreation, 161.

, cited on study hours, 189.

Ostwald, cited on conductivity of non-
aqueous solutions, 301.

, cited on dissociation in water, 384.

, cited on electrical conductivity of

solutions, 15.

, cited on law of mass action, 340, 346.

, cited on properties of salt solutions,

338.

Overton, Ernst, cited on retardation of os-
motic action, 25, 26, 27, 31.

Oxygen, function of, 153.

Paley, cited on animal food, 150,

Parks, cited on hygiene, 68.

Patrick, cited on effect of absence of
sleep. 166.

Paulhan, cited on individuality, 139.

Pencils, 178.

Pens, fine, use of, 176.

Perez, cited on individuality, 139.

Pfluger, cited on method of investiga-
tion of dispersion, 255, 256, 257, 267.

, cited on method of studying disper-
sion, 274, 287.

Photographic records, of deviation, 269.

Plato, cited on play, 160.

Playfair, Lyon, cited on dietaries, 92.

, cited on military rations, 151.

Ponsot, cited on freezing-points, 319.

Prentice, cited on diseases of eyes, 182.

Protopterus, views of, 218.

Questionaire, sent to students, 69.
Queyrat, cited on individuality, 139.

Ran A, brain of, 229.

, olfactory lobes, 288.

Raxke, cited on dietaries, 92.

Ranney, cited on diseases of the eye, 180.

Ranyieb, cited on epithelium of the lung,
204.

, cited on stomata, 237, 240.

, cited on taste-bulbs, 8.

Raoult, cited on freezing-points, 301.

Ratz, cited on dieletric constant of ani-
line, 373.

Rawitz, cited on significance ot stomata,
240, 241.

Recklinghausen, v., cited on stomata,
237.

Redtenberger, cited on dispersion, 260.

Reissner, cited on nerves of frog, 232.

Retvius, cited on taste-cells, 8, 9.

Reychler, cited on conductivity of non-
aqueous solutions, 301.

, cited on " free ions," 340.

Ribot, cited on fatigue, 59.

, cited on individuality, 139.

. cited on inherited emotions, 63.

, cited on moral degeneracy, 63.

Richards, cited on storage of oxygen, 155.

Richards, T. W., cited on physiological
aspect of dissociation, 339.

, cited on taste of acids, 14, et seq.

Richardson, cited on animal food, 150.

, cited on use of tobacco, 124.

Rockwell, cited on toxic products of
nervous action, 49.

396

INDEX TO VOL. 2.

Rohe, cited on hygiene, 68.

Romanes, cited on mind and body, 45.

Rooms, size of students', 155.

Ross, cited on motor control, 57.

Rumfoed, cited on substitutes for coffee,
114.

Russell, cited on influence of associa-
tions, 197.

Salamandra, veins of, 218.

Sanfoed, cited on legibility of letters, 183.

Sauthoff, A., cited on the vascular system
of Necturu.t, 202.

Schafee, cited on localization of func-
tion, 190.

Schillee, cited on play of man, 160.

Schlundt, H., cited on constants of sol-
vents, 342, 343.

, On the dielectric constants of pure

solvents ("title of paper), 353.

Schmidt, cited on epithelium of the lung,

Scheeinee, Kahlenberg and, cited on
freezing-points, 335.

Schulze, cited on epithelium of the lung,
204.

, cited on method of preparing sul-
phury 1 chloride, 370.

Schulze. Wallach and, cited on method
of preparing propyl nitrate, 368.

Schwalbe and Loven, cited on taste-bulbs,
8.

Schwaetz, cited on classification of cells,
236.

, cited on endothelial cells, 243.

Schwieggeb-Seidel and Dogiel, cited on
injection, 239.

, cited on stomata, 237.

Schweigger, Seidel, Ludwig and, cited
on stomata, 237, 240.

Scripture, cited on effect of activity on
brain, 46.

, cited on fatigue, 52, 53, 55.

, cited on influence of associates, 197.

Seats, school, 185.

Seguin, cited on need of motor activity,
158.

Sellmeir, cited on theory of dispersion,
261.

Sensations of taste, 11.

Sense of Taste, 7.

, action of solutions on, 1.

Scheezee, cited on diseases of eyes, 181.

Sidts, cited on influence of associations,
197.

Sieben, cited on method of studying dis-
persions, 253.

Sinclair, cited on fatigue, 57, 58.

Sleep, 163, 164.

Small, cited on influence of associations,
197.

Smith, cited on acid salts, 16.

, cited on cost of food, 150.

, cited on food analyses, 84.

, cited on tea and coffee, 109.

Smith, August, cited on effect of alcohol,
123.

Smith, Noble, Klein and, cited on stom-
ata, 237.

Solutions, actions of, on the sense of
taste, 1.

aqueous, nature of, 4.

, preparation of, 12.

, Va

Tan't Ruff's theory of, 3.
Solvents, Dielectric constants of, 353.
Soeet, cited on method of studying dis-
persion, 253.
Specteum, visible part of, 269.

Spencer, Herbert, cited on fatigue, 75.

, cited on foods, 126.

, cieed on inherited emotions, 63.

, cited on vegetable diet, 151.

Squire, C. A., cited on the brain of Nee-
turns, 202.

Stas, J. S., cited on method of preparing
bromine, 371.

Steiner, cited on brain of shark, 228.

Steinheil, cited on dietaries, 92.

Stevenson and Murphy, cited on nutri-
tion and dietaries, 68, 90, 96.

Stirling, cited on the lung, 204, 205, 206.

Stomach Fluids, analyses of, 140.

Stomata, 237.

, significance of, 240.

SY0IfT' cited on diseases of the eye, 180,

Talbot, Fox, cited on dispersion by
double oxlate of chromium and potash,
250.

Taste, alkaline, 18.

, of cathions, 22.

, of solutions of electrolites, 13.

, salty, 20.

, sense of, 7.

, sour, 13.

Taste-bulbs, 8.

Tea, analysis of, 109.

Teeeschin, cited on dielectric constants
of alcohols, 374, 386.

- — , , of esters of aliphatic acids, 377.

Theory of electrolytic dissociation as
viewed in the light of facts recently as-
certained (title of paper), 297.

Theses at University of Wisconsin. Papers
by H. W. Ochsner (pp. 203-210), A. Saut-
hoft and J. H, Van Vorhis (pp. 311-226),
C. A. Squire (pp. 227, 234), and A. W.
Meyer (pp. 235-246). [Embodied in paper.]

Thompson, cited on animal emotions, 61.

Thompson, Goodwin and, cited on die-
lectric constants of liquid ammonia, 343,

•»KQ
DOS.

Thompson, Angell and, cited on effect of
mental activity on circulation, 48.

, cited on effect of noise, 165.

, cited on mental troubles, 171.

Thompson, C. A., Vernon, Lee and, cited
on influence of associates, 197.

, cited on influence of body on mind,

174.

Thomson, J. J., cited on dielectric con-
stants and dissociating power, 355.

, cited on dissociating power of water,

341.

Thwing, cited on dielectric constants, 356,
368, 373, 374, 386.

Titus, Winifred, cited on preparation of
bromioe, 371.

Tobacco, influence of, 123.

Tomaszewski, cited on dielectric con-
stants of homologues of benzene, 377,
378.

Toueneaux, cited on stomata, 241.

Tower, cited on acid salts, 16.

Trevor, cited on acid salts, 16.

Turner, cited on dielectric constants of
ortho-nitro-toluene, 376.

, , quinoline, 367, 373.

Ueodeles, brain of, 227.

Van't Hoff, see Hoff, van't.
Van Vorhis, J. H., cited on [the vascular
system of ^Xeciurus, 202.

INDEX TO VOL. 2.

397

Vascular system of Kecturus, 211.

Veins of Necturus, 218.

Voigt, cited on dietaries, 92.

cited on reaction between matter and

ether, 264.
Vollmer, cited on ionizing power of

methyl alcohol, 357 .
Vulpius, cited on application, 193.

Waals, van der, cited on gases under

pressure, 348.
Walden, cited on conductivities, 343.
, cited on ionizing power of liquid

sulphur dioxide, phosphorus oxy-chloride

and arsenic trichloride, 357. 379.

, cited on non-aqueous solutions, 302.

Wallace, cited on mind and body, 45,
Wallach and Schulze, cited on method

of preparing propyl nitrate, 36S.
Warner, cited on "carelessness," 54.

, cited on mal-nutrition, 75.

- — , cited on motor control, 57.

Watt, cited on thebaino, 28.

Weber, cited on legibility of letters, 183.

Werner, cited on molecular weights,

38i

, cited on non-aqueous solutions, 302.

Wernicke, cited on index of refraction,

254, 255.
Wey, cited on moral degeneracy, 63.

Wet, cited on need of motor activity, 158.
Wiedeman, cited on polarization of re-
flected light, 251.
Wilcox, G. M., acknowledgments to, 311,

320.
Wiley, H. W., cited on food analyses, 89.
Williams, cited on epithelium of the

lung, 204, 205, 206.

, cited on tea, 113.

Wilson, cited on drunkenness, 6-?.

, cited on effect of alcohol, 119.

, cited on hygiene, 68 .

Winter, cited on analyses of stomach

fluids, 140.
Wojta, F. J., acknowledgments to, 72.
Wood, R. W., acknowledgments to, 287._
, cited on degree of dissociation with

dilution, 314.
, cited on method of investigation of

dispersion, 257, 269.
Wright, cited on moral degeneracy, 63.
Wundt, cited on influence of associates,

197.

, cited on mind and body, 45.

, cited on sensation of taste, 811.

Zanxinovich-Tessarin, cited on conduc-
tivities, 383.

, cited on ionizing power of formic

acid, 357.

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