Skip to main content

Full text of "The preparation & mounting of microscopic objects"

See other formats


This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project 

to make the world's books discoverable online. 

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject 

to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books 

are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover. 

Marks, notations and other maiginalia present in the original volume will appear in this file - a reminder of this book's long journey from the 

publisher to a library and finally to you. 

Usage guidelines 

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the 
public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing tliis resource, we liave taken steps to 
prevent abuse by commercial parties, including placing technical restrictions on automated querying. 
We also ask that you: 

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for 
personal, non-commercial purposes. 

+ Refrain fivm automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine 
translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the 
use of public domain materials for these purposes and may be able to help. 

+ Maintain attributionTht GoogXt "watermark" you see on each file is essential for in forming people about this project and helping them find 
additional materials through Google Book Search. Please do not remove it. 

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just 
because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other 
countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of 
any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner 
anywhere in the world. Copyright infringement liabili^ can be quite severe. 

About Google Book Search 

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers 
discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web 

at |http: //books .google .com/I 

i^TTxW ctkaSyy *:7iyrx!C 

1 ^^„%rvA^.^^/i^:y^^, 











Sittmd (K)nim.—§xtutlia (ffniarjtb* 

Edited by JOHN MATTHEWS, M.D., F.R.M.S. 
Vice-Fre». Q^€^ett Microse<^ic(d Club. 





'the N£w 








* • 

" •• •• ... 


rPHE reception accorded to this work has been so 
favourable as to indnco tlie Publisher to issue 
a second edittonj in which such new matter ebould 
be embodied as the progress of Microscopic science 
might require. He therefore applied to the Author, 
but he found to hig regret that the state of Mr. 
Daviea's health was such aa to forbid his under- 
taking the labour. He had, however, collected 
many valuable notes and memoranda, which he 
was willing to place at the disposal of any gentle- 
man who might be selected to edit the work. The 
Publisher then consulted the present Editor, who, 
after some hesitation, consented not only to use 
his best efforts with the ample materials placed at 


his disposal^ but also to make such additions as his 
experience might suggest in extension of the use- 
fulness of the book to a new class of readers, — the 
Medical Student, and the Junior Medical Practi- 
tioner. To this end, besides other matter, a brief 
prefatory chapter has been added, embracing the 
elements of preliminary histological manipulation. 
While claiming the indulgence of the elders of his 
profession, — ^the Editor feels that the best and truest 
apology for this treatise, its raison d^etre — ^in fact, 
may be found in the words of its concluding para- 
graph, to which the reader is now courteously 

4, Mtlne I^teeet, Mtddelton Squabe, E.G. 
October, 1873. 


TN bringing this Handbook before the public, the 
Author believes that he is supplying a want which 
has been long felt. Much information concerning 
the '^ Preparation and Mounting of Microscopic 
Objects ^' has been already published ; but mostly 
as supplementary chapters only, in books written 
professedly upon the Microscope. From this it is 
evident that it was necessary to consult a number 
of works in order to obtain anything like a com- 
plete knowledge of the subject. These pages, 
however, will be found to comprise most of the 
approved methods of mounting, together with 
the results of the Author^ s experience, and that 
of many of his friends, in every department of 


microscopic manipulation; and as it is intended 
to assist the beginner as well as the advanced 
student, the very rudiments of the art have not 
been omitted. 

As there is a diversity of opinion as to the best 
mode of proceeding in certain cases, numerous 
quotations have been made. Wherever this has 
been done, the Author believes that he has acknow- 
ledged the source from which he has taken the 
information; and he here tenders his sincere 
thanks to those friends who have so freely allowed 
him to make use of their works. Should, however, 
any one find his own process in these pages 
unacknowledged, the Author can only plead over- 
sight, and his regret that such should have been 
the case. 








Tms work having been written chiefly to help studentp, 
the writer does not venture to affirm of it that it is bj any 
means complete or exhaastive. The art of microscopic 
manipulation is progressive, and it is scarcely possible, 
therefore, to say of a work on the subject, that it holds all 
that is known at any given time. It is an art, too, which 
is BO inextricably mixed up with the highest branches ri 
scientific inquiry, that new modes of investigation are daily 
devised by the acntest intellects, and with these it is very 
difficult for a writer to keep pace. 

It is a well-nigh hopeless task to attempt to teach encli 
modes of inquiry by precept, yet it is felt that some short 
account of them may reasonably be expected here. Befci r 
ence is now made more particularly to the practical part of 
human and comparative histology. As this is not a treatise 
on histology, but is devoted mainly to the methods of pre- 
serving the results of researches in that science, it is scarcely 
possible to indicate to the student how he shall proceed in 
any given case ; yet there are certain tests, reagents, ani 
staining matters employed, with the uses and effects of 



whicli be slionld be familiar, so as to be able to speak with 
some degree of certainty of the natare of the tissues demon* 
strated by them. 

It is now, therefore, intended to give the reader a list of 
these aids, arranging them according to the effects which it 
is desired to produce. Strieker observes, ** that it is to be 
borne in mind that it is impossible to say of any fiaid that 
it constitutes an indifferent, i,e., neutral, medium for fresh 
tissues of all kinds. In all instances we must be prepared 
for changes taking place." He gives, however, a list of 
fluids to which structures are generally most indifferent, i.e., 
in which least alteration may be detected under examina- 
tion while fresh, viz. : — 

1st. Fluid of the aqueous humour. 

2nd. The senim of the blood. 

3rd. Amniotic fluid, very fresh, in which a little iodine 
has been dissolved, making it of a faint yellow tint. 

4th. Very dilute solutions of neutral salts, such as phos- 
phate and acetate of soda and potash, &c. 

It is scarcely within the power of any one -observer to 
have largely used or tested the whole of the processes here- 
inafter to be mentioned. The writer therefore freely admits 
his obligations to the treatises of Drs. Beale and Carpenter, 
Mr. Qnekett and Mr. Fownes, as well as to those of Strieker, 
Frey, Klein, Schultze, Kiihne, Deiters, Leber, and others, 
many of whose processes he has personally verified, and of 
whose manuals, especially those of Beale, Strieker, and Frey, 
the student is advised to possess himself. He believes also, 
from his own early experiences, that some short rationale 
of the intentions of the processes and means of investigation 
used by well-known workers may be acceptable to the stu- 
dent, in repeating their experiments before embarking in 
any of his own. 

These materials and methods may be divided, then, and 
described according to their effects somewhat as follows ; 
and it is in the judicious selection of each one or more of 
them that the tact and discretion of the student will best 

ECTs. a 

1m bIiowh. Ke slionld boar !□ luind, too, that tho same 
Btrncture may well be snbmilted to sarious modes of in- 
qniry. and tbut poasiblj new iDodt^s maj occar to bim wbich, 
thonj;h they may not aerre to prove anything directly, may 
jet beoome negative proofs. 

lit. Bach tests and agents as render transparent oi 
translucent some tissueB but not others adjacent, or malia 
(Ome mare eonspieuous than othera without colouring them, 
ir at least hat faintly. 

Sod. Staining materials or flnide, which colour either all 
the tisanes to ba displayed, or some particular part nr pirta 
of them, thns making such tiiisaea or parts more conspicuous 
when anbaequently eiamined or preserved in a colaurlese 

3rd. Hardening egcnts or aolationa, by the effect of 
trbich tiesuea naturally ao soft aa to break down or be other- 
tnageable under maoipnlation, are made firm 
enough for aectioo, or for BQoh eiaraination as may suffice to 
to discriminate (Or "differentiate") their parte, without 
either diatnrhing or confusing thtir structnral relations. 
4th. Softening agents of animal and vegetable tissues. 
Bth. SotvuntB of the same. 
6th. Solvents of ealcareous matter. 
7th. Solvents of silioeona matter. 
8th. Solvents of oily and fatty matters. 
fltb. Polarized light, by the agency of which atrncturea 
and organs may often be optically differentiated as a pre- 
UminBry to other modes of investigation, 
10th. Eltctricity and heat. 
11th. The moist chamber. 

In dealing with stracinres by means of the agenta com- 
prised under the firet division of oar list, a very frequent 
■nd necesBBi'y preliminary is the teasing out or separation 
f fibres by means of two abarp needles set in convenient 
AiidleB. Bat it must he rememliori^d that an appearance 
of Btractore, where it does not really enist, may easily be 
B produced. It is often necessary, also, that the object 


shall have been macerated in water, or some other agent, 
for 80 long a time as may be required to loosen or dissolve 
the connective tissue. Tt is of these agents that we shall 
presently have to speak in detail, greater or less according 
to their relative importance. Boiling or steaming may 
often be employed with advantage. It mnst not be too 
hastily concluded that, because there is nothing at first 
visible, there is therefore nothing to be seen. There are 
many important tissues which are apparently structureless, 
or homogeneous, which yet are possessed of such diverse 
elements as absolutely to require some process by which 
they may be optically or visually differentiated, if one may 
nse such a phrase, i.e., discriminated from the neighbouring 
tissues or organs. It is thus that their proper uses and 
purposes in relation to the whole organism may be correctly 
indicated or inferred, their histological nature decided, and 
their physiological relations and connections established be- 
yond doubt. 

The student is also very emphatically cautioned against 
the use of objectives of very wide angle, as well as of 
deep eye-pieces. In the former case, the relations of 
structures to each other can never be well made out, since 
it is impossible to get a focus of any depth (i.e., of all the 
structures involved), in one view, because the objects in one 
plane only can be clearly seen, the rest, either above or below, 
being more or less out of focus, and therefore hazy and 
indistinct. This objection applies far less to those of lesser 
angle, which are therefore the beat for histological purposes. 
In the latter case, we have nearly the same defect to con- 
tend with, viz., that surface markings only, or mostly, can 
be seen clearly (not to speak of the loss of light). The use 
of the draw-tube is the true remedy for this. 


lar DiviMoN, 
TToder i^nr first tea.! may be raageiJ the following ; — 
Acetic acid. 
Iiiquor potaat^Ee and sodro. 

icentrateii sulphuric and hjdroclilorio acids {the latter 
saturated nit^ dilorine). 

Lime and barjta water. 
Oxalic acid. 

Nitric acid witli cblorate of potasb. 
Gljcerine (?) 
Pbospborio acid (tribaflic). 

Acetic acid mora or lesa dilate, e.g. one part to fi^e of 
water, after a aofScieotlj prolonged immersion, reoderB 
iran^arent tbfl following tiesnes, without in geDeral des- 
trojiing their connective tissue: — some tnusdes (of the frog 
(EKlliber),) cell-walls generally (ont the oucleas), epithelial 
fltmotaree, while Bbroua tissue. Dr. Beaie sajs that yellow 
flbrouH tisane is uuallered hy it. Many kinds of formed 
tnalerial, acctiona of preparations which have been hardened 
by alcohol. Dr. Beale also aaya that it dissolvea granular 
matter compoi^ed of albuminous material, and that many 
tiuDea are quite insoluble in it, though they are not ren- 
dered opaque by it. Acetic acid renders some tissuea trans- 
parent by dissolving out the phosphate or CEirbonate of lime, 
vhioh they may oontaiD, but it bas no similar snkent power 
over oxalate of lime. Farts which are unaffected by this 
arad are then made more conapicuous. 

Liquor polas^is and liquor sodte act in much the same 
way, according to the degree of their dilution, but on different 
Btrnctnrea. Albumiuona tissuea, cpitbulinm, &c., are either 
dlBiotved by them or rendered ao traneparent aa not to 
, obslmct the view of the aubjacent stmctaves, 


Concentrated snlpburic and lijdrocliloric acids, used cold, 
cause epidermic stractares to swell up, so that their cells 
may be easily separated. 

Tannin, dissolved in water or rectified spirit of wine, 
hardens gelatinous and albuminoid tissues : it also makes 
them shrink. Its solution in water has been used, as men- 
tioned in another part of this treatise, as an injection pre- 
liminary to one of coloured gelatine, to prevent extravasation 
through the walls of the blood-vessels. It also colours the 
tissues a fawn-colour, or a very faint brown. 

Lime water and baryta water, especially the latter, will, 
according to Kullet, dissolve the animal cement by which the 
fibres of connective tissue are held together. After a few 
days' soaking such tissue, as well as tendon, may easily be 
teased out by needles. 

Oxalic acid, in a cold saturated solution (I acid, 15 
water), according to Schultze, " causes connective tissues to 
swell up and become transparent, while those formed of al- 
buminous substances become hardened and isolated. Ex- 
tremely delicate elements of the body, such as the rods of 
the retina, &c., are thus well preserved." 

Strong nitric acid mixed with chlorate of potash destroys 
connective tissue in a short time, and is therefore a good 
.medium for isolating muscular fibres (Kiihne). 

Sulphuric acid, highly diluted (1 to 1,000 parts of water), 
used warm, gelatinizes connective tissue, and is also useful 
for the isolation of muscular fibres. 

Strong hydrochloric acid dissolves the intercellular sub- 
stances of organs abounding in connective tissue. 

Ammonia acts on animal matters much in the same way 
as potash and soda. 

Alcohol coagulates albuminous tissues, and makes them 
opaque. It corrugates most transparent membranes, and 
thus renders them more visible. 

Finally, it may be affirmed that there often exists a need 
of making objects which are too dark more transparent by 
means of a fluid which permeates them uruqually, bo thsit 

OF Micftoscopic oBJKcrs. 7 

10 tiBsaea are ttereby aa it were " differentiated," jet nob 
altered in any material degree. This maj be effected by 
so1utioD8 of gun), pugar, glycerine, aod crensute, if the 
tisBueB are moist. If dry, then turpentine, Canada balsam, 
benzine or benzole, and the essential oils of clovee, aniee, 
and caBHia, may be employed. 

2nd DiYisioB. 

tJnder the secaDd divieioa of our subject oome ataining 

Many of theae wilt be found mentioned in the body of this 
worlc. They comprise carmine Bolutione, botli acid and 
alkaline; aniline coloora, indigo, carmine, baimatox^linc, 
&c, formnltB for the nee of which are given. To these Prey 
adds, bine tingeing by moljbdate of ammonia, and doublo 
staining by carmine and picric acid. 

A neutral solntion of the molybdate of ammonia of the 
atrength of 5 per cent, gisea a bloe tint to nBrTe-tisBna. 
lymphatic glands, and ciliated rpitht'lial cdls, after macera- 
tion for 24 hours iu the light. 

For double staining by carmine and piorio acid he recom- 
mends a mixture containing — 

1 part creosote, 
10 parte acetic a< 
20 parts water. 


Soak the tiesnes in this eolation while boiling for about a. 
minute, then dry for two days. Wake thin sectioDS of them, 
imiaerse fur an hour in irater fuiutly acidulated with 
acetic acid, and then waah in distilled water, Next place 
tbem in a very dilute watery Hiilution of ammoniacal car- 
mine, waeb again iu water, and place in a sulutioa tif picrio 
acid in water, the strength of which will vary according to 
circnmHtancuii. The sectiona are then to be placed on a 
dlide, super&uoDB acid allowed to drain off, and a mixture ol 
4 parta creosote to 1 of old resinous torpcntine dropped on 


them. In about half an hoar thej will become transparent, 
and may be monnted in Canada balsam. 

*' A peculiar effect is thus obtained. Epithelial and 
glandalar cells, muscles, and the walls of vessels show a 
yellowish colour, with reddened nuclei, while the connective 
tissue is not coloured by the picric acid, and only presents 
the carmine colour." 

Another mode of effecting the above is by adding to a 
saturated and filtered solution of picric acid in water, a 
strong ammoniacal solution of carmine, drop by drop, nntil 
neutralization takes place. Sections may be soaked in this 
solution, more or less dilute, for a sufficient time, and 
treated as in the previous method. 

The other staining agents are : — nitrate of silver, osmic 
acid, chloride of gold, chloride of gold and potassium, proto- 
chloride of palladium. These are to be made into weak 
solutions in distilled water, in which the tissues, in section 
or otherwise, are to be placed, and then exposed to light for 
a sufficient time. 

L'ber recommends a mode of staining by Prussian blue, 
as follows : — Immerse the specimen in a weak solution 
of a protosalt of iron for five minutes, more or less, 
according to size or the thinness of the section. Then 
wash and move it to and fro for a few minutes in a 
1 per cent, solution of ferro-cyanide of potassium until it 
assumes an intense and uniform blue colour. Then wash 
in water, soak in alcohol, and mount as usual. The effect 
is that of partial tingeing ; the colour penetrates very 
deeply, and the tissue may be subsequently stained with 
iodino, carmine, or fuchsine. This method has been used for 
the cornea of the frog. 

Iodine 1 part, with 3 of iodide of potassium, dissolved in 
600 of water, may be used for tingeing of a brown colour 
animal cells, as well as all amjloid substances, animal or 
vegetable, sulphuric acid being added. 


3aD Division. 

Under the third diviBiOD of oar list maj be ranged the 
followiog agenta : — alcobol, solotioDS of chromic acid, bi- 
chromate of potaah, hjperosmic acid, chloride of palladium, 
bichloride of raercnry (in Goadbj's aolulion). and tannin, or 
the Bubstaoce may be dried in thin layers or small pieccB, 
either epoDtaneoDsly or in vacao, or by oarerully regolated 
heat ; in sDDie Cases it may be boiled, or it may be frozen. 

Alcohol is, on the whole, the beat and raoat cooceuient of 
the hardening agents. It acts by abatraoling water and 
coagolating atbumcn, and its nses aa a presorrative fluid 
per se are well known. It enters also into many of the 
preserTative fluids, and ia eapecially convenient and useful 
when it ia deaired to mount apecimens quickly out of watery 
flaids in Canada balsain, without drying them previonaly. 
After a longer or shorter soaking in it, according to their 
aiie or thioneas, preparations may be at once placed in tnr- 
pentine, and then easily and speedily pot op for eiaraina- 
tion in balsam. 

Dr, Beale recommenda a mixture of alcohol and a soln- 
tlon of caustic soda for the preserTation of delicate tiasnes. 
He observes, " that alcohol alone tends to coagulate albn- 
minouB textures and rendor them opaque, at the same time 
that it hardens them. The alkali, on the other hand, will 
render them soft and transparent, and wonid dissolve them 
if time were allowed. These two fluids, in conjunction, 
harden the texture, and at the same time make it clear and 

Chromic acid in solntion, 025 — 0-5 to 1 and 2 per cent. 
of distilled water ia much used. On acconot of its deli- 
qnescence, it is most convenieotly kept in a saturated sola- 
tion, which may be dilated as desired ; and very often the 
weaker this aolutioo the better. When it baa had the de- 
sired effect on the tissue, the preparation should be removed 
iota dilated alcohol, on accooat of the readineGs with which 
fangi and confeivoid growths are formed in chromic acid 


BolatioDS. There are some precautions needed for perfect 
saccess with this agent, for which the reader is referred to 
Frey's " Microscopic Technology." 

Bichromate of potash, in solutions of similar strength to 
those of chromic acid, may be used in the same way, but is 
far slower in producing its effect, and therefore inferior in 
the opinion of many. Strieker, however, says, '* that it has 
the great advantage that tissues saturated with it do not 
become friable, and that the time occupied by this agent, 
as well as by the preceding, may be much shortened by re- 
moving the preparation into alcohol for twenty-four hours." 

It is always advisable to divide the substances to be har- 
dened into portions as small as convenient, since the larger 
often putrefy in the centre, though they harden at the sur- 
face. It is quite certain that many of the more delicate 
structures, such as the rods of the cochlea of the ear 
(Pritchard), those of the eyes of insects, &c., are better 
prepared with this than by the preceding agent. One great 
element of success in these two processes is, that the volume 
of the solution should be very large in proportion to the 
size of the object; another, that the action should be 
commenced with a weak solution, and continued with a 

It sometimes happens that objects may be hardened too 
much by these solutions, though there is less risk by the 
bichromate of potash. In such cases Frey recommends that 
they be soaked in glycerine for a few days, and even that it 
be added to the solutions at first. He, with Deiters, Arnold, 
Scholtze, and Kiihne, claims for these solutions an effect of 
the most important kind, viz., that of " preserving the finest 
textural relations, while exerting a somewhat macerating 
action on them, so that very delicate organizations, especially 
in nerve tissues, may be made visible which were previously 
hidden, or not visible in examination of the fresh tissue." 

Hjperosmic acid and chloride of palladium are sometimes 
used for this purpose also. Their solutions may contain 
from one-fifth to one-tenth per cent, of distilled water. 

or MicEtttfonc objects. 11 

Bichloride of meTenrj acts, in hardeoiiig tis.*u«a (like 
most of the preceding, probablj), ty conibiciiig and forming 
ftn inaoluble compound with their albuminoid elements. It 
is Dot mnch employed for this purpoee, bnt is principallj 
of use in certain preaervatiTe Bolalioiis mentioned elsvwhero 
in these pages. 

Tannic acid forma inaolnble componnda trith a great 
Tariety of organic and especially animal substanceB, as bii1u< 
tions of starch and gelatine, solid maacular fibre and skin, 
&c., which then acquire the power of resisting putrcfdo- 
tion. It Bcaroely oolonra animal membrane. Dr. Benle 
Bays that its action upon red blood corpasclea is " Tt'rj 
pecnliar." The Eolation need is three grains to an oanoe of 
water. Other nsea of tannin (tannic acid) will be found 
elsewhere in this work, and the intelligent student wilt easily 
tbence infer its action and properties. 

Drying may be effected either in a current of warm dry 
air, or under a bell-glasa oier sulphuric acid, or over a lajfer 
of parched oatmeal ; or a cheap form of water hath may be 
employed, auch as will be found described in thia work. 
Another very speedy method is to soak tfae speuimen in 
strong alcohol for a sufficient time, remove it, and expose to 
a corrent of warm dry air. 

Boiling. — Tiasnea may he hardened by boiling in a. fluid 
conaiating of 8 parts water, 1 part creosote, and 1 part 
Tinegar, for two or three minutes. They may then be kid 
out to dry. After two or three days they acquire a firm- 
nesa admirably adapted for section ; bat if they remain too 
long uncut they become of a consistence unfit for that pnr> 
pose. On the whole, boiling is not to be recommeDded, 
though Strieker says that it baa ita occasional uacs. 

Freezing may be employed for otherwise unmanageable 
etrnctures, auch as brajn, spinal cord, &a. (though there 
BeeniB to be an oltjuction of a theoretical kind to this use of 
it, Tiz., that it may iojare or alter the cells), or other tfssuea 
wliich will notadmit the u»e of chromic acid, or which it may 
be desired to view usder other aspects. 


Tbe writer has little or oo ei[>erieiiee of this pIoD, he 
therefore qnotea from Frey as folIowB : — 

'■ Tne preparation ia allowed to freeee (by contact, it ia 
preBomed, with a freezing miitare or solution) nntil it as- 
■umeB a oonBistencj which will permit fina lectionB to bs 
inaJe with a cooled razor. The ol^ect is more coDreuietit to 
handle if it ia allowed to freete on a piece of uorV. Nerrea 
and mDBclea have been treated in this manner with good 
results. Glands (aalivarj), livers, spleeaB, the Innga, sMa, 
and the bodiea oF embryoii (see Beoile's process for the b: 
in this work), also ganglia, afibrd excellent appearances. 
Indifierent (or neutral) media, each as iodine serum, s 
be used in examining auch sections. Or the preparation may 
be held in paraffins wax (dilated or not with oil), or talloWi 
which have been melted, and the ohject saapended or 
plunged in them until they cool, and tbe cooling may be 
carried fiirtlier, if nocdcd, by freezing." 

In reference to this subject, Mr. Kesteven informi 
author tbet he has foand tbe paiaffine composition mora 
nstful for brain than spinal cord. Tbe former can be oat 
into any angnlar shape, and be so held steady for slicing; 
but the cord, being round, becomes loosened in its setting of 
wax (or paraffine), and resolves with the pressure of the knife, 
For either brain or cord he prefers hand-cutting with a vary 
sharp razor, after the manner of Lockhart Clarke (see Mr. 
K>-Bteven'B paper in 6t. Bartholomew's Hospital Beports). 
If many eeotions are to be made from a brain, machine- 
cutting saves much time. The razor should have t 
spirit of wine dropped on it, bo ae to prevent the 8eotLon» 
adhering. The cutting machines are generally graduated 
(by a screw and index) on the upward movement, so as to 
enable one to judge of the thickness of the section ; bnt aa 
the brain substance and paraSne are both yielding to a cer- 
tain extent, the reading mnst be taken with allowance. 

07 KiCKosconc oBJict*. 13 

4t[i DivisiOH. 

lUa inclades gljcerins, liqnor potoMffi and «odit>, hfni (u 
regards »ome Babstances), maceTntiou (carried lii inoipient 
pntrescence), nitrio and oblor-hjdrio aaids, elllior pura ur 
dilate (ia the cose of bones, nails, &<:.). 

The writer is in donbt whether glycerine onglit nr not to 
be indnded under this aection or the first, ill u*pii niid 
effects being ao varioaa and interealing. ladrcd, tbprii it 
Bcarcel; an; agent tn which hiiitologjr in mora iudvbtnd for 
its present status and progress, since there is now no donbt 
that elementary tisane can he more readily didwiiniufttnd lo 
this medium — perhaps, too, hij it — -than any otlier. Tt has 
also the valonble property of preseniug tho tiKsuen, if it he 
not too much diluted, and even then it is geoprally eHoutiiat 
if camphor water be employed as the diluent. Tho ntrongest 
and beat glycerine should always be employed, The flrit 
effect on tisanes immersed in it is that they shrink, owinj} 
to the abatraction of their water; bnt Dr. ISi'ulo upeiiUs in 
the highest terms of its nnes and advuntagcn, nnd declare* 
that the tissues gradually regain their original Tolunio it' 
left in it for a sufSuient time. They then soften, and eTeti 
swell up. nia practice is first to immerse the Npcciinen in 
tueak glycerine solntion, and then gradually to Incrciinc the 
density of the fluid. Ho recommends, also, " in ordi^r thul 
tiasnes may be oniformly permeated nith a HuJd wilhiri n 
very short time after the death of an animal, tliab thn llniil 
shonld come quirkly in contact with every part of the texture.'* 
This, he saf a, may be effected in two ways, by 

a. Soaking very thin pieces in the fluid; 

S. By injecting the tloid into the f esselfi of the animftl. 

He thinks that these properties more particulnrlj np]ier- 
tftio to glycerine than to any other medium, and afSrnil 
tliat"cerebral tissues, delicate nervoon tisinea liho tho retin* 
or the nerTe-teitarcs of tbs internal car, may he aatarkl«4 
with it,anii dii»ection then earruxl la a degree of v ' 


impas^ihh -in any other inediiim. All that ii required is, 
that the streogth of the fluid should bo increased very 
gradaally natil the whole tisane is thoronghly penetrated bj 
the stroDgest that caa be obtained;" and " that thus very 
hard iexluree may be softened, eo that b; gradaally increas- 
ing preseore and careful manipulation esceediogly thia 
layers can be obtained, without the relation of the anatomic 
cal elements to each other beiug mach altered, or any of tba 
tisBuea destroyed." He also takes ocoaaion to ohaerve, "that 
tissues immersed in water are destroyed by even moderate 
pressure-, but that iu a viscid medium (such as glycerine or 
Bjrnp) the requisite pressure can be borne not only without 
injury or impairment of the discrimination of their parts, 
hut with advantage to their detail." One very great advan- 
tage which results from the use of glycerine for the prepara* 
tion of texturfS ia, that however they may swell in it after 
prolonged immersion, a aofflcient soaking in water will 
always restore them to their normal condition, Anoth 
that on account of its very high refractive power, it ia 
peculiarly fitted for the preparation of struoturea to be ii 
veetigated by polarized light, with the same advantage as i 
the preceding caae, that they are still amenable to all other 
modes of inquiry. 

The caustic alkalies — potash, soda, and ammonia 
solvents of all animal textarea except chjtine, and perhaps 
bone. As in nearly all caaea a softening action, with little 
or no alteration of tissue, precedes the solvent action, theae 
agents, end especially the first two, have tlieir uses. Under 
their influence " a condition is induced very favourable tO' 
the imbibition of water, which afterwards penetrates very 
rapidly, so that cells swell np and burst." T bey may bo 
used either with or without beat, and more or lesa dilute. 
There is one disadvautage attending their nee, that objects 
can with difficulty be preserved after soaking in them. 

Heat, applied either by the aid of hot water or steam, o 
the aand-bath, or a bath of fusible metals, or of melted lei:d, 
is a very efficient means of softening horny substanaeB, whale- 


Tjone, Ac, and rendering them plastic. Very thin laminw of 
these Bnbstannes luaj also be procared by the employ m I'll t 
of a well-sharpened scraper, each as that need by cabinet- 
mabera. This plan applies laore to longitndinal than to 
transverse sections^ yet even the latter may be obtained by 
finog the object while soft in a piece of hard wood, and 
Gcraptng both together. Long continued slow boiling softens 
and eventnally disintegrates nearly all aninial and vegetable 
tissDes. Muscular fibre aod many other textores may thas 
he isolated, such as spiral vessels, &e., in vegetables. 

Prolonged maceration in water, for the preparation of 
anatomical stroctnres, generally bony, is a process too well 
known to need description here. The addition of very 
dilate nitric, hydrochloric, and acetic scids is much em- 
ployed for the separation of mnscular fibres, both striated 
and smooth. Two or three days are required, or even more. 

^ails may be softened very qoickly by hot concentrated 
Bolphoric acid — or, still better, by liqoor potaspEB, strength 
about 25 to 27 per cent.~so as to show isolated and dis- 
tended cells by solution of the intercellular aubatance. 

Bones are softened, i.e. decalcified, by boiling or, atill 
better, by slow maceration in weak solutions of nitric and 
hydrochloric acids, by the action of which the phosphate 
and carbonate of lime may be entirely removed. This pro- 
cess isolates the animal matter, i.e. the osaeine— sometimes 
miscalled gelatine — with all its peculiar fibres and processeSi 
Bat bones may be treated in another way, so as to ahuw or 
isolate the hone corpuscles with their processes, by removal 
or destruction of the intercellular sobataDca. Though this 
can scarcely be called softening them, yet it may be most 
fitly mentioned here. For this purpose, a Papin'a digester 
ia DMeseary. When the boiling of bones has been for a long 
|time carried on by means of one of these machioes, they 
^seetn to be dissolved ; hut on examination a coarse powder, 
COBBiHting of the isolated corpuscles and their processes, ia 
fotmd at the bottom of the vessel, which wilt amply repay 
the trouble of eiamicatioQ, 


Teeth may be treated in the same manner as bone0, except 
for the examiDation of the enamel, which is best effected by 
sections and grinding. For that purpose developing teetii 
sbould be chosen, as in them the enamel prisms are most 
easily isolated. 

5th Division. 

As the solution of animal and vegetable tissues generally 
means the confusion or destruction of their histological 
elements, not much can or need be said of it here, except 
that it may be as well to indicate the special solvents and 
tests of the special components of all tissues, since it is upon 
a correct knowledge and appreciation of the degrees and 
differences of the action of these, that effective histological 
research must chiefly depend. 

Albumen, when pure, is nearly insoluble in water, wholly 
80 when coagulated by heat. In dilute caustic alkali it 
dissolves with facility. Solution of nitrate of potash, acetic 
and tri-basic phosphoric acids, and pepsine, dissolve the pur- 
est form of albumen procured from white of egg. 

Fownes observes, " that it must be remembered that a 
considerable quantity of alkali and very minute quantities 
of the mineral acids, prevent coagulation by heat, and that 
the addition of acetic acid, indispensable to the test by mer- 
cury, produces the same effect." 

Fibrin e of blood is insoluble in both hot and cold water, 
but is partly dissolved by long-continued boiling. Fresh 
fibrin e, wetted with concentrated acetic acid, forms after 
some hours a transparent jelly, which slowly dissolves in 
water. Yery dilute caustic alkali dissolves fibrins completely. 
Phosphoric acid produces a similar effect. Fibrine of flesh, 
which is not identical with that of blood (Liebig), is soluble 
in cold water containing one-tenth of hydrochloric acid. 

Casein is only soluble in water in the presence of free 
alkali in very small quantities. It is partly soluble also in 
very dilute acids. 



Gelatin, chondrin, and OBseine are the result of tlie bolliog 
of animal membranca, Btin, tendonp. and bonea, respectively 
1 high temperatare for a sufficient time. Thej aru 
inaoloble in cold water, but easily diasolved bj the nse of 
heat. Alcohol, corrosive Bnblimate in eicesB, nitrate of 
mercnry, and, most characteristically, tannin, precipitate 
gelatine — -the latter when it is very largely dilnted. 

" Sliin and tendons contain aGnbstaacu which resists the 
action of boiling water for many hours. It is iosoloble in 
cold concentrated acetic acid, bat by long- eon tinned boiling 
in it, ia ^adnally dissolved, and more easily in hydrochloric 
acid." (Fowoes.) 

Horny aobstance — ieratin, fonnd ia hair, nails, feathers, 
and epithelium, is obtained by finely dividing them, treat- 
ing them with hot water, and afterwards by boiling alcohol 
and ether. The horny substance is then Tery Bolnble in 
canBtic potash. 

Of bonas we have already spoken. 

It baa been mentioned elsewhere in this work, that all 
tie internal organs of insects may easily be dissolved out by 
Iwiling in liquor potastie, leaving their external cbitinoaa 
stractnres, limbs, &c., unaffected. Bat this is a proceediDg 
mncb. to be deprecated, for various reasons which it ia 
scarcely necessary to give here. It ia far better to treat 
them in another way, by which these organs may be cr- 
amined w aifv, at least to a Tery great extent, as will 
presently be shown. 

The parenchyma of leaves and many other vegetable 
stmcturea may be decomposed by prolonged maceration in 
watar, and then easily be washed away. Nitric acid, vary- 
inglj dilated, will pradace the same effect more speedily, the 
objeota not r^quiricg the same amount of bleaching snhse- 
qnently. But by far the best and most speedy method is, 
to place them in the liqnid manure tank of the gardener 
for a sufficiently long maceration. The results of this plan 
■re eiqnisitely beautifol. 

6th Div'aioN. 

The proper eolventa of cakareona animal matters ars 
nitric, bydrochlocio. and Bnlphuric acida. The earth of 
bones conaista of a combination of two tribaeic phoaphatM 
of lime, both of which are entirely soluble in nitric aoS 
hydrochloric acids. Salphnric acid abstracta a part of thi 
lime of bones, learing a aaperpboaphate — -a aabatance mnoli 
nsed in agricultare aa a manure. Flaoride of calcium, 
existing in small quantity in bones, bot ia larger ii 
enamel of teeth (and of the ganoid acalea of fish P), ia do- 
composed by Bnlphario acid, which combines with the cal< 
cium, allowing the hydrodaoric acid to 9y off in a, gaseous 
state. Carbonate of lima diasolvea in nitric and hydro* 
chloric acids. The abella of mollusca, and testte of echino- 
dermata, oonsiating principally of carbonate of lime, ari 
Bolublo in the same acids, as well as those of nnmmnliteS 
foraminifera, &a., which have been infiltrated with eiliceoas 
matter. These present the most beautiful " casta," whioli 
are exactly of the shape of the Sarcode body and canal sys- 
tem, thns enabling their internal organa to be atudied witi 
much accuracy. Dr. Carpenter aaja that they are of " 
derfnl completeness." 

7th Divbiok, 

Silica is nearly altogether insoluble id water, but dissolTe* 
freely in strong alkaline solntions. Its only acid solvent ii 
hydrofluoric acid. Its combinationa with a larger proporti 
of alkali are soluble in water, and from such solutions ailioc 
may be precipitated in a gelatinous or colloid form bf 
Bcida, or separated by dialysis, in the form of colloid silica. 
This Bubstance may be used for procuring certain modifica- 
tions of cryatala of aalta for the polariacope, anch as anlphats 
of magnceia, sulphate of copper, boracic acid, sulphate of 
&c. In its combination with a smaller proportion of alkali, 
forming glass, it is attacked by hydrofiuorio acid and Jla 
vapour, and advantage may be taken of this property ta 

ECTS. 19 

engrave tiBmea, nitnibera, tc., neaUj opon sUdea, far dassifi- 
c^on in tbe cabinet. The g-Issa to be eogrsTed must be 
ooftted wilL in etching pronnd of oily varnish or wax. and 
the upceasajj writing efiecl^d upon it bj a point, which 
UQst pierce tfarongh the prot«cIJ*e dat^rial. A ehallow 
bauD, made bj l^sdiiig up the edges of a piece of sbeet-lead, 
is then prepared, a little powdered £iior epar placed in it, 
and enoagb salphnric acid added to form a thin paste. The 
g]aet is then placed in any oonvenient way over the basin, 
the waxed side don^wards. A gentle heat ta next applied, 
whereby the vaponr of hjdroflooric acid is disengaged. This 
acta upon the glass exposed by the point in a very few 
minatee, removing a portion of ite surface. The icai most 
thea be removed by tnrpentJiie. If the lioes which result 
are then robbed over with any colonred vamish, and the 
Tarnish gently wiped off bj a soft piece of rag, a sufficient 
portion will most probably remain in the etched marks to 
render them easily visible and legible. Of conrae it will be 
as well to prepare eaaoy slides in this way at once. It is not 
neceBBar; to coat the whole sarf&ce of the slides with the 
jirotectiTe varnish, if the leaden basin be covered with a 
thin piece of wood or sheet-lead perforated with holes 
slightly larger than the sarface to be etched, over which 
holes Uie slides mnst be inverted for a snffiuicnt time. This 
latter hint applies more particularly to finished slides requir- 
to be labeUed. 

8th Ditisios. 

The proper solvents of the fiiod oily and fatty matters 
lie ether, benzole (or benzine), turpentine, and the essen- 
tial oils generally. Castor oil is nearly the only one which 
18 Milnble in aleofaol, the rest being only slightly so, Tbey 
are all capable of saponification with oaaetio alkalis, and so 
become indirectly soluble in soft or distilled water, other- 
wise tbey are wholly insoluble in it. 

The volatile or essential oils mix in all proportions w 
&tty oils, and are wholly soluble in ether and ale 


Campbor dissolves in a only very small proportion in water, 
but freely in alcohol, ether, and strong acetic acid. 

9th Division. 

It is by no means intended to speak here of the general 
properties and uses of polarized light. Bat in relation to 
its special powers in the ** differentiation " of tissues, there 
is very mnch to be learned. To be fitted for examination 
by this method, objects must be made more or less trans- 
parent or translucent ; and in effecting this it is advisable, 
perhaps necessary, to employ media of high refractive power. 
Even when so prepared, it may be further necessary in some 
cases to employ seleoite or mica films, still more to enhance 
their colour. Not the least indication can be afforded to the 
observer as to what colours he should employ generally, yet 
it is a matter of frequent observation that what are called 
•* neutral tints *' are to be preferred, such as result from the 
judicious use of compound selenite stages adjusted properly 
for that special effect. 

The media mof^t suitable for the preparation of objects to 
be examined in this way are glycerine, syrup, turpentine, 
dammar and benzole — or the latter alone, Canada balsam, 
and the essential oils. Of course sections must be made of 
.tissues otherwise too thick. Of the advantages of employing 
the first of these we have already spoken ; but to these must 
be added this important one, that it does not spoil the object 
for examination by other methods, if the gljcerine be soaked 
out by maceration in water; and this is true also of syrup, 
though it is far less useful. For preparation by the other 
methods, tissues must have been soaked in alcohol, and then 
removed into the turpentine, &c. 

For the examination of insects by polarized light, two 
preliminaries are necessary. Firstly, that they be made 
transptirent or translucent by prolonged soaking in one of 
the above-named media, preferably in turpentine or the 
essential oils, or benzole. Secondly, that as in (mostP) 
many of them their chitinous case is too deeply coloured for 


any araannt of soaking to render them BnfficiEntl; trans- 
parent, same hleaching prooesa ahoalJ l>e premised, A for- 
mnla for such a process may be fiionil ia another part of 

~ a work, where the preparation of the autennKt of iasecta 
is dpSDribed. If that shoald not prove Bucoositfiil, some 
raodificattoQ will easilj occur to tlie student. Of coiirae it 
at all insects that can he treatiid in this way, the siaie 
and deep colonr of very many quite preventing a good 
result; bat when they have been BncceaBfully prepared by 
any of the methods of which we have apoken, it ia thea 
possible to discrimioate their internal organs by the differ- 
ences of colour which they preaent. The nse of the binoonlar 
microscope, and of objectives of low angnlar aperture, will 
also iDQab facilitate thia mode of examination, by i[ 
the depth of focus, and enabling the organs to be ai 
or leas in connection with each other, even if they be super- 
posed, lb is also poasible to eramine the mnaclus of the 
limbi and bodies of insects, so as to decide upon their forma- 
tion, origin, and insertion, and probable mode of astioti; and 
is only one of many sach nsea. What a mistake most 
it be, then, to prepare insects for monnting by boiling in 
liqaor potassro, and so disaolving out their viscera, and 
squeezing them flat! 

In the case of living insects, especially those of the mora 
tranaparent salt and fresh water species, the reaalts of their 
examination by polarized light are exqnisiti^ly beautiful and 
interestiug, becanse their organs and circulation may be 

nore olearly discriminated while in motion. 

10th DivisiOK. 

Eleotrioity has been employed in histology partly for its 
electrolytic effecta, but chieQy as a means of producing 
Mitain variations of temperature in objects under eiamina- 
tion, Strieker saya " that the tiasues become altered by it 
aa they wonld be were they subjected to the action of weak 
acids or alkalius," and ho describes a rather complicated 
apparatus for thia purpose, of which it is impoBsible to giva 

22 PSErAfliTioN ASD MOUKTtso 

an account here ; bnt the anthor believea that moat, if not 
aX, of tbe Bame effects maj be prodnced b; (he emplojmeQt 
either of a thick plate of metal placed upon the stage, o 
a thin water-bath, which may be heated by a spirit or _ 
flame, after the glass slide shall have been placed on it. 
Tbey sliODld both be properly fitted with therm ometere. 

Of the decomposition of salts by electricity, and their n 
daction to the metallic state, it is not necessary to speak 
here, bat such effects are very hcautifal, and the resulting, 
crystal ization may easily be watched. 

Dr. Beale speaks very favoarably of the inverted i 
Hcopa devised by Dr. Lawrence Smith, TJ.SA., by whidi 
objects may be viewed from their ander instead of from their 
upper suiface, and at Iho same time heated (or re-agents 
applied to them) withont any risk of dimming or ioj 
the object-glass by vaponrs thns raised. The optical part 
ia so fitted to tbe base that in may be drawn away from be- 
neath the stage (to make room for the application of the 
lamp, or) for the sake of changing the powers. 

IIth Division. 

It is evident that in all theKe plans an amoant of evapo- 
ralioQ is constantly going on, nhich will eventually dry and 
80 spoil the objpct, unless obviated. Frey, therefore, desoribei 
a "moist chamber" invented by Eecklinghansen for this 
purpose. It consists of a glass ring, more or less high, 
which has been cemented by its edge to a broad glass slide. 
A tube of thin rnbber is then firmly fastened about the nog. 
Tbe upper end of this tnbe is also fastened around the tuhfl- 
of tbe microscope. In order to keep the place thus enclosad 
saturated with moisture, some small pads of wetted bibulooa 
paper, or pieces of elder pith also saturated with fluid, i 
be enolosed with the object, which in this ease need not be 
covered with thin glass in the usual manner. It is 
ceivable &lso that this apparatus may easily be converted 
into a gaa chamber, by fixing two small, light valoanizsil 


tnbes into tbat which embraces the glass ring and the end 
of the microscope tube — one for the entrance, the other for 
tbe exit of the gas. This is a simpler and less costly plan 
than that devised bj Strieker, Frey observes that it is 
most advantageous to nse immersion lenses and the moist 
chamber v^ith the hot stage. 




Before entering into the subject of the setting of Objects 
for the Microscope, the student must be convinced of the 
necessity of cleanliness in everything relating to the use of 
that instrament. In no branch is this more apparent than 
in the preparation of objects ; becanse a slide which would 
be considered perfectly clean when viewed in the ordinary 
way is seen to be far otherwise when magnified some hun- 
dreds of diameters ; those constant enemies, the floating 
particles of dust, are everywhere present, and it is only 
by unpleasant experience that we fully learn what deanU' 

71688 is. 

An object which is to be viewed under the microscope 
must, of course, be supported in some way — this is now 
usually done by placing it upon a glass slide, which on 
account of its transparency has a great advantage over 
other substances. These ** slides " are almost always made 
of one size, viz., three inches long by one broad, generally 
having the edges ground so as to remove all danger of 
scratching or cutting any object with which they may come 
in contact. The glass must be very good, else the surface 
will always present the appearance of uncleanliness and dust. 
This dusty look is very common amongst the cheaper kinds 
of slides, because they are usnally made of " sheet " glass ; 
but is seldom found in those of the quality known amongst 
dealers by the name of " patent plate." This latter is more 
expensive at first, but in the end there is little difference in 
the cost, as so many of the cheaper slides cannot be used 
for delicate work if the mounted object is to be seen in per- 
fection. These slides vary considerably in thickness j care 


bIioqU, tberefare, be taken to sort tLem, bo that tlie more 
delicate objectH with which the higher powers are to be 
TiBed maj be mounted apon the Ihhiuest, an the light em- 
ployed in the illumination ia then less interfered with. To 
aid the microscopiat in this work, a metal circle may be pco- 
cored, having a number of different sized openings on the 
oater edge, by which glasa slides ciin be measured. These 
(^ninga are numbered, a.nd the slides may be sepiiruted 
tUKMirding to these nambersj so that whea mouctitig any 
object there will he no need of a. long search for that gkse 
which is best saited to it, 

When fresh from the dealer's bands, these slides are 
generally covered with dual, &<;,, which may be removed by 
well washing in clean rain-water; bat if the imparity is 
obstinate, a little washing soda may he added, care being 
taken, however, that every trace of this ia removed hy aub- 
saqnent waters, other<iviee, crystals will afterwards form npon 
the Borface. Sometimes, however, a certain greaaiaeBa ia 
very ohatinate opoii the glaaa. It ia then necessary to uae 
B little liqnor potaasao with a small piece of linen, rubbing 
tfae slide with some pressure, and then washing as before to 
remove all remains. A clean linen cloth should be used to 
dry the slides, after which they may be laid by for nee. 
Immediately, however, hufore being naed for the reception of 
ohJeetB by any of the following proceaaea, all dust must be 
removed by rubbing the surface with clean wash-leather or 
B piece of cambric, and, !/ needful, breathing npon it, and 
then Dsing the leather or cambric nntil perfectly dry. Any 
Bmftll particles left upon the surface may generally be 
removed by blowing gently upon it, taking care to allow no 
clarop to remain. A very efficient remedy, also, is a mixture 
of equal parts of sulphuric ether and alcohol, with which 
the glass must be rubbed by the aid of a tuft of clean 
eottoQ-wool until no stain oppeara after breathing upon it, 
A strong infusion of nutgalls may be used in the same way, 
and is preferred by many to all other applications; or, a 
mutture of equal parts ot alcohol, benzole, and liquor sodw 


may be employed, irhicb tborongbl; and speedily cleaneec 
glass from all traces of greaae or bulaam. 

We ha»e before said thftt any olgVct to be viewed in tbi 
TDicroGCope miat have its snpport; bat if this object is to 
be preeerved, care mnat be takea that it ih di^fended boat 
daat and other imparities. For this pnrpoBe it ia necee 
to nae aome transparent cover, the most uenal at one 
being a plate of mica, on account of its thinneBS; this 
stance ia now, however, never naed, tbiti glaes being Bubsti^ 
toted, which anawers admirably. Some^mfa it ia required 
to " lake lip " aa little apaoe aa posBible, owing to the short 
neBB of focna of the object-glaasea. It can be procured a 
any thiulcness, from one-fiftietb to one-two-bnndred-aiid' 
fiftieth of an incb. On a:Cconnt of its want of etrengtb, aw 
probable defect of due annealing, it is diScoIt to cnt, as i 
ia very liable to "fy" from the point of the diamond. Ti 
overcome this tendency as much as possible, it must be laij 
upon a thicker piece, previonalj made wet with water, nbioh 
caasea the thin glass to adhere more firmly, and oonso 
qnently to bear the pressnre required in cutting the d 
The proceaa of catting being so difSeult, especially with tU 
thinner kinds, little or nothing ia gained by cutting tho* 
which can be got from the dealers, as the loss and breafcag 
ia necessarily greater in the bauds of an amateur. It i 
convenient, however, to have on hand a few larger pieoeK 
from which nnusnal sizes may be cat when required. 

If the pieces required are rectangular, do other apparatni 
will be required aave a diamond and a flat role ; but I 
inVc'es are wanted, a machine for that purpose ahould b 
used (of which do descriptiou is necessary here). There aro) 
however, other contrivances which answer tolerably well 
Ono method is, to cat out from a thick pipce of cardboard i 
circle rather larger than the aize wanted. Dr. CiirpeotSI 
recommeuds metal rings with a piece of wire soldered on 
either side ; and this, perhaps, ia the best, aa cardboard is 
apt to become rough at the edge when much used. A friea^ 
of mine Dses thin brass plates with circlea of varioas eieet' 



" turned " throagli them, and a smiLlI raised handle placed 
at one end. The diamood muet be passed rouod the inner 
edge, and so managed as to meet again in the same line, in 
order that the circle may be trne, after which it may be 
readilj diaeogaged. The sizee naaally kept in atock by the 
dealers &re one-hair, Sve-eighthB, and three-quarters inch 
diameter ; but other sizes may be had to order. 

For the JDformation of the beginner it raay be mentioned 
here that the price of the circles ia a little more than that 
of the eqoares; but this is modified in some degree by the 
circles being rather lighter. If appearance, however, is 
cared for at all, the circles look mnch neater upon the slides 
when not covered with the ornamental papers ; but if these 
last are naed (a« will shortly be described) the squares are 
equally serviceable. 

As before mentioned, the thin giaas \e made of various 
thicknesses, and the beginner will wish to Icnoiv which to 
nae. For objects requiring no higher power than the one- 
inch object-glaes, the thicker kinds serve well enongh ; for 
the half-inch the medium thickness will be required ; while, 
for higher powers, the thinnest covers must be used. The 

' " test-objects " for the highest powers require to be brought 
so near to the objeot-glaas that they admit of the very 
thinnest covering only, and are usually mounted betwixt 
glasses which a beginner would not be able to use without 
ft-eqnent breakage ; but if these objects were mounted with 
the common covers, they would be really worthless with the 
powers which they require to show them satisfactorily. 

It may be desirable to know how such small difTerencea 
as those betwiit the various thin glass covers caa be 
measured. For this purpose there are two or three sorts of 

J apparatue, all, however, depending npon the same principle. 

I The description of one, therefore, will be snfScient. Upon a 

1 Hoall stand is a short metal lever (as it may be termed) 
which returns by a spring to one certain position, where it 
ia in contact with a fised piece of metal. At the other end 
tbis lever ia connected with a " Eager," which moves round 


a dial like tliat of a watcb, whereupon are figures at fixed 
distances. When the lever ia separated from the metal 
which is stationary, the other end being connected with the 
" finger," of the dial, that " finger " is moved in proportion 
to the dintance of the separation. The thin glass is, there- 
fore, thrust betwixt the end of the lever and fixed metal, and 
each piece is measared by the figures on the dial in stated 
and accurate degrees. This kind of apparatus, however, is 
expensive, and when not at our command, thin glass may 
be placed edgewise in the stage forceps, and measured very 
accurately with the micrometer, or by the calliper eye- 
piece described by Dr. Matthews in No. 8, for October, 1869, 
of the Journal of the Quekett Microscopical Club. 

Cleanliness with thin glass is, perhaps, more necessary 
than with the sides, especially when covering objects which 
are to be used with a high power ; but it is far more difficult 
to attain, on account of the liability to breakage. The 
usual method of cleaning these covers is as follows : — Two 
discs of wood, about two inches in diameter, are procured, 
one side of each being perfectly flat and covered with clean 
wash-leather. To the other side of these a small knob is 
firmly fixed as a handle, or where practicable, the whole 
may be made out of a solid piece. In cleaning thin glass, 
it should be placed betwixt the covered sides of the discs, 
and may then be safely, rubbed with a sufficient pressure, 
and so cleaned on both sides by the leather. If, however, 
the glass be greasy, as is sometimes the case, it must be 
first washed with a strong solution of potash, infusion of 
nutgalls, or any of the commonly used grease-removing 
liquids; and with some impurities water, with the addition 
of a few drops of strong acid, will be found very useful, but 
this last is not often required. 

This method of cleaning thin glass should always be used 
by beginners ; but after some experience the hand becomes 
80 sensitive that the above apparatus is often dispensed 
with, and the glasses, however thin, may be safely cleaned 
betwixt the fingers and thumb with a cambric handkerchief. 

OF MicROsconc OBJECTS. 29 

haTing Erst Blightlj danipod the enda of the fingers employed 
lo obtain firm bold. When the dirt is very obstinate, 
breathing npon the glaea greatly faoililatea ita removal, and 
the sense of touch becomes ho delicate that the breakage is 
iocon aid arable ; but tbia method cannot be recom mended lo 
tmricea, as nothing bnt time apeiit in dolicate maQipaltktioa 
can give the aeoaitiveneas required. 

It has been before mentioaed that ordinary glass sidesi aro 
Bometiniea wortblesa, etpeciallij for fine obj-cig, from having 
a rough snrfuce, whicb preaents a dasty appearance nnder 
the microaeope. Tbia imperfection eiists in some tkiii glass 
bIbo, and ia irremediable; so that it is tiaelesa to attempt to 
cleanse it; nevertheless, care ehonid be taken not to miatake 
dirt for this ronghness, lest good glass be laid aside for a 
&iilt which does not really belong to it. 

When any object whicb it is desired to mount ia of eon- 
riderable thickness, or will not bear pressure, it is evident 
tLat a wall must be raised aronnd it to sopport the ttiin 
g'aea — thia is naually termed a "cell," There are various 
deacriptiona of these, according to the class of objei:ts they 
are required tn protect; and here may be given a description 
Cif those which are most generally used in mounting "dry" 
objects, leaving those reqnirpd for the preservation of liquids 
until we come to the consideration of that mode of mounting. 
Uany havB need the following slides. Two pieces of hard 
wood of the naual size (3 in. by \ in.), not exceedini{ one- 
sixteenth of an inch in thiekness, are taken, and a hole ia 
Qien drilled in the middle of one of these of the size required. 
The two pieces are then onited by glcie or other cement, 
and left under pre.isnre until thoroughly dry, when the cell 
is fit for use. Others substitnte cardboard for the lower 
pieae of wood, which is less tedious, and is strong enough 
for every purpose. This class of "' cell " is, of conrse, fitted 
for opaque objects only where no light ia required from 
below i and aa almoat all such are lietter seen when on a dark 
backgrODud, it is usual to fix a amull piece of black paper 
ftt the bottom of the cell upon which to place them. For 


reiy Rmall objectB the grain whicli all each paper h 
vfaen magnified detracts a little from the merit of tl 
backgraand; and latelir I have used a small piece of thiA 
glaea covered on the back with black varoish, and placed thl 
object upon the smooth □□toacbed aide; but a Bolution of 
the best Egyptian asphalt ia benzole of moderate thick* 
neiB msj be painted on with this further advantaga, 
that in mountiog Buch opaque objeuts aa fursmioifera, iiA, 
it will be Buffioient to arrange them in the positiooa thef 
are to occupy, when by elightly narmiog the slide thsf 
will adhere to the asphalt. 

Another method of making these cells ia aa followa ;— ^ 
Two puncbeR, similar to those nsed fur cutting gun-wadSi^ 
are procured, of such sizes that with the smaller mav be cati 
out the centre of the larger, leaving a riug whose side is i 
less than an one-eighth of an incli wide. Tbeae rings ma/^ 
be readily made, the only difficulty being to keep the side*, 
parallel ; but a little care will make this easy enough. ~~ 
this purpose close-grained cardboard may be coaTeniently 
DHed. It moat have a well-glazed surface, else the y 
t t>r cement used in affixing the thin glass cover ainks into tbfl 
■'Substance, and the adherence is very imperfect. When tbil 
I takes place it is easily remedied by brushing overt" 
face of the cardboard a strong solution of gum c 
glass ; and tliia application, perhaps, closes also the porefl 
of the card, and so serves a doubI(3 purpose. Bat, oC 
course, the gum must be perfectly dried before the ring i 

For cardboard, gutta-percha baa beeu substituted, bi)| 
cannot be recommended, as it always become brittle aft4 
a certain time, never adheres to the gloss with the required 
firmness, and its shape is altered when worked with e 
little beat. Leather is often used, and is very convenient) 
it should be chosen, however, of a close textnre, and frei 
ii-oni oil, grease, and all those snbstances ivhich are loii 
upon it by the dressers. 

Bings of cardboard, Ac, have beeu rejected by persons oi 

ot aiCBosconc objects. 31 

great esperieoce, beoaaaa they are of suuh a nature tliat 
dampneas can penetrate them. This faalt can be almoat, if 
not totally, removed by imraeraing tbem in aome strong 
vamiah, each as the aaplialt Tarnish hereinafter mentioned; 
but they must be left long enongh when affixed to the glasa 
alide to become peifectly dry, and this will rec[uire a maoh 
longer time than at Qrst would be BUppoaed. 

There haa, however, been lately brought ont what ia 
termed the ivory cell. Thla is a ring of irory-lilcQ subatiince, 
vhicb may be easily and firmly fixed to the glaaa alide by 
any of the commonly need cements, and ao forma a beautiful 
cell for any dry objects. They are made of different Bizea, 
andarenot expcnaive. Flat rings of brass torned down to the 
eizea of the oircular diaca of covering glasa and of varying 
tbiokneas are very neat and useful for monnting opaque 
objects: they can also be obtained in tin and zinc. 

Some of our beat microacopio men have stated that they 
have bean freqnuntly diaappointed by an accumulation aC 
enorUBted matter npon the inner surface of thin gliias uaed 
to cover the cell enclosiag any dry object, and therefore nae 
a shallow pillbox, made exprsaaly for thia pnrpoao, which 
maat be atroogly cemented to the alide. For examination, 
the lid must be removed, whilst it must be closed to proteob 
the object from dust when laid aside. Another worker of 
experience reoommenda a cell in a mahogany slide, over 
which, by aid of a atud aa on a pivot, a bone disk can be 
turned: thia ia termed, "Pipec'a Revolving Cover Slide," 
and can be procured at the opticiana'. 

Sometimes slides are used which are made by talcing a 
thin alip of wood of the usual size (3 in. by 1 in.), in the 
centre of which ia cnt a circular hole large enough to 
receive the object. A piece of thin glass ia Gxed underneath 
the shde forming a cell for the object, which may then be 
covered and finished like an ordinary slide. This hiia the 
advantage of serving for transparent objecta for which the 
before- mentioned wooden alides are unsuitable. A alight 
modification of this plan ia often used where the thickueas 


of the objects is inconsiderable, especially with some of tlie 
Diatomaceas, often termed "test-objects." The wooden 
slide is cut with the central opening as above, and two 
pieces of thin glabs are laid npon it, betwixt which the 
diatoms or other objects are placed, and kept in their proper 
position by a paper cover. This arrangement is a good 
one, insomach as the very small portion of glass through 
which the light passes on its way to the microscope from 
the reflector causes the refraction or interference to be 
reduced to the lowest point. 

A novice would naturally think the appearance of some 
of the slides above mentioned very slovenly and nnfinished ; 
but they are often covered with ornamental papers, which 
may be procured at almost every optician's, at a cost 
little more than nominal, and of innumerable patterns and 
colours. How to use these will be described in another 

It is very probable that a beginner would ask his friend 
what kind of slides he would advise him to use. Almost 
all those made of wood are liable to warp more or less, even 
when the two pieces are separate or of different kinds ; those 
of cardboard and wood are generally free from this fault, 
yet the slides, being opaque, prevent the employment of 
the Lieberkuhn. To some extent glass sides, when covered 
with ornamental papers, are liable to the same objection, 
as the light is partly hindered. And sometimes dampness 
from the paste, or other substance used to affix the papers, 
penetrates to the object, and so spoils it, though this may 
be rendered less frequent by first attaching the thin glass to 
the slide by some harder cement. Much time, however, 
is taken up by the labour of covering the slides, which is a 
matter of consideration with some. Certainly the cost of 
the glass slides was formerly great; but now they are 
reasonable enough in this respect, so that this objection is 
removed. It is, therefore, well to use glass slides, except 
where the thin glasses are employed for tests, &c., as above. 
When the thin glass circles are placed upon the slides, and 

scTS. 33 

the edge ia varaislied witli black or coloared rings, the 
ftppearance of fiaisfa. is perfect. The trouble is mach less 
Uiau with most of the other metliods, and the iUamiuation 
of the object very slightly impaired. 

To TBrniBh the edges of these coTers, make circles of any 
liqnid upon the glass slide, and perforoi aoj other circalar 
work mentioned hereafter, the little instrument known as 
Shadbolt'a .turntable " is almost indiEpensable. It ia made 
9 follows ; — At one end of a Bmall piece of hard wood is 
fixed an iron pivot about one-eighth ioch thick, projecting 
lialf an inch from the wood, which serves as a centre npon 
which a ronnd brass table three inches in diameter revolves. 
On the snrf^ce of this are two springs, abont one and a half- 

■h apart, under which the slide is forced and so kept in 
position, whilst the ceutral part is left open to be worked 
npon. The centre is marked, and two circles half an inch 
inch in diameter are nsuallj deeply engraved npon 
the table to serve as gnides in placing the slide, that the 
ling may be drawn in the right position. When the slide 
is placed npon the table underneath the spricgs, a camel- 
lair pencil is filled with the varniHli, or other medium used, 
and applied to the surface of the glass; the table is then 
made to revolve, and a circle is consequently produced, the 
diameter of which it is easy to regulate, Mr. Hislop places 
two equidistant pins at opposite sides of the centre of 
revolving plate, against which the opposing edges o< 
the slip are made to bear, so tbiit the instrument is self- 
centering. The springs are turned in contrary directions anil 
ore screwed on the plus, or the screws are made into tho 
pins against which the sides of the slide bear. 

The form of this " turntable " bus been modified by many 

anipulators to anit their several wants. Almost all slides 
nsed are of nearly the same size — 3 in. by 1 in. ; and therefore 
the centres of all are equidistant from the edge. On this 
account one of my friends has a thin brass bar screwed upon 
the side of his turntable in such a position that the centres 
of the slides and table alsvays coincide. The rings of varnish 


upon the slides and tbia glass upon the cell are thus Vept 
■uniform. Dr. MatthewB, u gentleman of no little eiperience, 
has giTenuB an improTemont as followB ;■ — Take two " ' 
of tlie average thickneaa of a glaas slide, f inch wide, 2^ 
long. Each of theae ia pivoted on the face of the tomtable 
by a screw throagh its centre, each screw being placed 
esactly eq^nidiatant from the centre of the tnrntable, so tHat 
the jaws are separated by a space aa wide aa'an average 
elide ; i.e. a full inch. Oatside of that space, on one aide of 
the centre of one of the jawe, is a wedge fixed by a acre 
Buch a way as to bo capable of motion in the direction of 
its length by a alotted hole. This is all the machinery, 
AB and CD are the two j'awB, E is the wedge. On placiDg 
a, slip between the jaws they probably at first do not toaeh 
it. If the wedge be then pashed so as to approximate B to 
C, the jawB move on their centres, so that, however far B 
may be pnahed towards (and moving) C, the other end of 
— i.e. J) — is moved exaMy as much in the opposite direC' 
tion nntil they approach near enough to grasp the slide by 
its edges. The length of the wedge mnat, of oonrae, be such 
BS to provide for about \ inch variation in the width of 
elides. It will readily be seen that the slip may be pushed 
in either direction eicentricaliy lengthwise, bo aa to allow of 
the formation of any nnmber of cells, all of which mast 
needs be central as regards their width, if the instrament 
has been accnrately made, which is a very easy matter. 
have added also a rest for the hand, F, which may be turned 
aside on a centre at will, and which I have found to be a 
j^reat convenience. 








Mr. SpeDcer sliglitlj modifies tlie aboTo, using wood 
jaws and wedge, which the following engraving will best 


Many objects for the microscope may be seriously injured 
by allowing the fingers to touch them — many more are so 
minute that they cannot be removed in this way at all, djA 
often it is necessary to take from a mass of small grains, as 
in sand, some particular particle. To accomplish this, there 
are two. or three contrivances recommended : one by means 
of split bristles, many of which will readily be found iB 
any shaving-brush when it has been well used. The bristles 
when pressed upon any hard surface, open, and when the 
pressure is removed close again with a spring ; but the use 
of these is limited. Camel-hair pencils are of great service 
for this, and many other purposes, to the microscopist. 
In very fine work they are sometimes required so small that 
all the hairs, with the exception of one or two finer pointed 


inea, are reni07ei]. A few of Tarioug Bizea should alwaje be 
:ept on hand. 

Equally ncocflaary ai'e fioe-pointed neeillea. They are 
very readily put np for nae by thrusting the eye end into 
a penholder, bo as to he firm. The points may be 
readily renewed, when iojared, on a common whetstone ; 
of aae they may be protected by being thruat 
into a piece of eorV. 

la laying oat animal tieanes that have been stained by 
iiitrate of silver or chloride of gold, it is advisable to employ 
I Hmal! rod of glass drawn out to a point, as the use of a 
ooetallio point eauaes a deposit of gold or ailver at the place 
>f contact, which diafigares the preparation. 

~ ' ' rarious iiinds are required ia some branches 

of microscopic work ; but these will be described where 
3isBectioD, &c., in treated at some length, as aleo various 
forma of scisaors. In the most simple objects, however, 
Bcisaors of the usual kind are necessary. Two or three 
jizea should always be kept at hand, sharp and in good 

A set of glass tubes, kept in a case of some sort to 
prevent breakage, sboald form part of our fittings, and 
be always cleaned immediately after nee. Tbese are 
generally from six to ten inches long, and from one-eighth 
to a quarter of an inch in diameter. One of these should 
be straight and equal in width at both ends ; one should be 
drawn out gradually to a fine point; another should be 
pointed as the last, bnt slightly curved at the compressed 
' ir to reach points otherwise nuattainable. It ia 
well to have these tubes of various widths at the pointa, as 
e waters the finer would be inevitably stopped. For 
other purposes the fine ones are very useful, especially in 
■ the transfer of preservative liquids which will come under 
notice in another chapter. 

Porceps are required in almost all microscopic manipu- 
lations, and consequently are scarcely ever omitted From the 
, microscopic box, even the most meagrely furnislied ; but of 


these there are varioas modifications, which for certain 
purposes are more convement than the nsaal form. The 
ordinary metal ones are employed for taking op small 
objects, thin glass, &c. ; but when slides are to be held over 
a lamp, or in any position where the lingers cannot con* 
veniently be used, a different instrument mnst be found. 
Of these there are many kinds ; but Mr. Page's wooden 
forceps serve the purpose very well. Two pieces of elastic 
wood are strongly bound together at one end, so that they 
may be easily opened at the other, closing again by their 
own elasticity. Through the first of these pieces is loosely 
passed a brass stud, resembling a small screw, and fastened 
in the second, and through the second a similar stud is 
taken and fixed in the first — so that on pressure of the stnds 
the two strips of wood are opened to admit a slide or other 
object required to be held in position. The wood strips are 
generally used three or four inches long, one inch wide, and 
about one-eighth inch thick. 

Again, some objects when placed upon the glass slide arc 
of such an elastic nature that no cement will secure the 
thin glass covering until it becomes hard. This difficulty 
may be overcome by various methods. The following are 
as good and simple as any. Take two pieces of wood about 
two inches long, three-quarters wide, and one-quarter thick; 
and a small rounded piece one inch long, and one-quarter in 
diameter; place this latter betwixt the two larger pieces. 
Over one end of the two combined pass an india-rubber 
band. This will give a continual pressure, and may be 
opened by bringing the two pieces together at the other 
end ; the pressure may be readily made uniform by paring 
the points at the inner sides, and may be regulated by the 
strength of the india-rubber band. These bands may be 
made cheaply, and of any power, by procuring a piece of 
india-rubber tubing of the width required, and cutting off 
certain breadths. Another very simple method of getting 
4ihis pressure is mentioned in the "Micrographic Dictionary." 
Two pieces of whalebone of the length required are tied 

Cr inrrp.nKiTrqr eEXrzs. I^ 

together firmlj at each eni. Ii s mdecx lih&i £xt Diiifizrt 
placed betwixt ihem. wO be Bcipfici uS saTirmfcZ proEcnL 
The power of this msj be r&rxLL&:«i Ij line r.V i^jrwro azL^ 
length of the whaleboine. Tnis Kim^"^ cacizfrcjkK je tctj 

Almost ererj mnmmi^-^^. xnsn. Lowers', L&e lie rvrs m^ifl, 
and it maj be as wdl to ezamizie oiifr or xwj x tbezc ICr. 
Goode uses the foillowizLg: A, a yi^sx of itdic ^ ix. l:aig 
and i in. thick. B. a fprzuz zziade ^vriih iiizi irjin "vire. 
The end of the fpiing is diiTezi ilio ^be idtlilf::, as a* C. A 
piece of ^-in. iron nire is then ran ihiZ'^zh tie, irr.icih 
fonns an axis to woik upon, ani &Iso keeps iLezi ir ibeir 
places. He incerU a pin ai iLe siie cf u.e spiisz, bj that 
it will fall on a gxren spot, and zjot r::^ tike i-iTer friiia siie 
to Bide. The springa are made Lj bin-^Tng the ih'.Ti wire 
round the j-in. rod about fonr or f re l:ipe». 





Mr. J. B. Spencer's model is made thtiB : — It is formed 
of thio sbeet steel (obtainable at any instium!?nt mater's), acd 
cnt ont in one piece, of the form above, with a stoat pair of 
SOTS, and then bent the required shape with a pair of 
Ts. "When nsed, the fore and middle lingers are applied 
the under side, and the thnmb on the spring. If great 
pressure la required, two clipa may be nsed, — HDne at each 
end of the slide, — -and for any delicate work the tindth of 
the steel can be reduced. 



The American wooden epring clips are occasionallj verj 
asefol, and wire clips of the kind described by Dr. Carpenter 
>n now commonly sold and are indispensable. 

Common watch-glasses should always be kept at hand. 
Thpy are certainly the cheapest, and their transparency 
makes them very convenient reserroirs in which objects may 


be steeped in any liquid ; and the use of tliem saves mucli 
trouble in examining carsorily under the microscope, whether 
the air-bubbles are expelled from insects, Sue, &c. They are 
readily cleaned, and serve very well as covers, when tamed 
upside down, to protect objects from dust. For this latter 
purpose Dr. Carpenter recommends the use of a number of 
bell-glasses, especially when one object must be left for a 
time (which often happens) in order that another may be 
proceeded with. Wine-glasses, when the legs are broken, 
may thus be rendered very useful. 

As heat is necessary in mounting many obejects, a lamp 
will be required. Where gas is used, the small lamp known 
as "Bansen's" is the most convenient and inexpensive. It 
gives great heat, is free from amoke, and is readily affixed 
to the common gas-burner by a few feet of india-rubber 
tubing. The light from these lamps is small, but this is 
little or no drawback to their use. Where gas is not avail- 
able, the common spirit-lamps may be used, as they are very 
clean and answer every purpose. 

In applying the required heat to the slides, covers, &c., it 
is necessary in all cases to ensure uniformity, otherwise 
there is danger of the glass being broken. For this purpose 
a brass plate at least three inches wide, somewhat longer, 
and one-eighth of an inch thick must be procured. It 
should then be affixed to a stand, so that it may be readily 
moved higher or lower, in order that the distance from the 
lamp may be changed at will, and thus the degree of heat 
more easily regulated. This has also the advantage of 
enabling the operator to allow his slides, &c., to cool more 
gradually, which, in some cases, is absolutely necessary, — 
as in fusing some of the salts, &g. 

In order to get rid of air-bubbles, which are frequently 
disagreeable enemies to the mounter of objects, an air-pump 
is often very useful. This is made by covering a circular 
plate of metal with a bell-glass, both of which are ground so 
finely at the edges that greasing the place of contact renders 
it air-tight. The pump is then joined to the metal plate 


tiQiIcmeatb, acid worked wttli a email handle lilce a 
Bjricge. By tnrning a sraall milled head the air may be 
ttllnwed to re-enter when it is reqnired to remove the bell- 
glaas and eiamine or perform any operalion uppn the ohject. 
The mode of using this instrument will be described here- 
after, bnt it may be liere stated that sabstituteB hare been 
devised for this naefcil appftratus; hat as it is now to be 
obtained at a low cost, it ia hardly worth while to consider 
them. Much time is, in many inetaiices, certainly saved by 
its use, as a very long iminersiou in the liquids would be 
reqnired to eipel the bobbles, where the air-pump would 
remove them in an hoor. 

The next thing to be considered is what may be termed 
Cements, some of which are neeeasary in every method of 
monnting objects for the microscope. Of these will be given 
the oompoailion where it ie probable the young student can 
use it ; but many of them are so universally kept as to be 
obtainable almoet anywhere; and when small quantities 
only are required, economy suffers more from home maou- 
faotnre than from paying the maker's profit. 

Amongst these, Cakada Balsam may, perhaps, be termed 
the most necessary, as it is generally used for the preserva- 
tion of many transparent objects. It ia a thick liquid resin 
of B light amber-eolonr, which ou exposure to the atmosphere 
becomes dry and hard even to brittleness. For this reason 

~s seldom used as a ceiiient alone where the surface of 
contact ia small, us it would be apt to be displaced by any 
sodden shock, especially when old. In the ordinary method 
of naing, however, it serves the double purpose of preserring 
the object and fixing the thin glass cover; whilst the com- 
paratively large space npon which it lies lessens the risk of 
displacement. By keppiog, this substance becomes thicker! 
a very little warmth will render it liquid enough to use, 
eren when to some extent this change has taken place. 
When heated, however, for some time and allowed to cool, it 
hecomes hardened to any degree, which may be readily 
Kgnlated by the length of time it has been eipoaed, and 


the Bmoant of heat to which it has been, subjected. Oa 
aceouDt of this property it is oftea used with chloroform : 
the bftleam ia exposed to heat until, on cooling, it assatneB 
a, glaaay appearance. This will be most readily done by 
baking it iu what we should call a " cool oven." Tho time 
required will most likely be 20 or 30 lioura. Care muat be 
taken that the heat ia not too great, elae the balsaoi will be 
discoloured. It muat then be dissolved in pure cblorofonn 
or benzole (the latter ia preferable) until it becomes of the 
couustence of thick varnish. This liquid is very couvenieot 
in some casea, as air-bnbbles are much more easily diapelled 
than when nndilnted Canada balsam is used. It also dries 
readily, aa the chloroform evaporates very quickly, for which 
reason it must be preserved in a closely -stoppered bottle. 
It baa been said that this mixture becomes cloudi/ with loQg 
keeping, bnt I have not found it bo in any caaes where I 
have used it. Cloudiness is most freqnently, if not alnkys, 
caused by dampness in the object, as mentioned in Chapter 
IT. Shoald it, however, become so, a little heat will gene- 
rally dispel the opacity. The ordinary balsam, if exposed 
mnch to the air whilst being used, becomes thicker, as baa 
been already stated. It mity be reduced to the required 
consistency with common turpentine; but I have often found 
this in Bouie degree iojuriooB to the transparency of the 
balsam, and the amalgamation of the two by no means 
perfeol;. (See also Cbaptor IT.) Its cheapoesB renders it 
no extravagance to use it always undiluted i and when pre- 
served in a bottle with a hollow cover fitting tightly around 
the neck, both surfaces being finely gronnd, it remains fit 
for use much longer than in the ordinary jar, Canada bal- 
sam may now be procured in collapsible tin tubes, like those 
used by artists ; and its manipulation is thus rendered muoh 
more easy, cleanly, and convenient, as well as economical. 
Chloroform ia, however, frequently used for dilution, and is 
perhaps the safest solvent we can employ. 

Dauhak Taenish. — Some complain that thia varnish la 
not easily procurable in a pure transparent statfi. It is 
e^^ nsed by oar American friends in moantiug diatoms 

ECT3. 45 

and other fine work. It is very liquid, and ia tbougbt by 
soma to be more easily worked than Canada balsam. 
Dammar may be eaai]y dissolved in benzole to any extent. 
Tiie lumps should previously be scraped nntil they are freed 
from dnst and other impurities, and then rongbly crashed. 

AspHALTUM. — This substance ia dissolved in linseed oil, 
turpentine, or naphtha, and is oflen termed " Brunswick 
black." It is easily worked, but is not generally deemed a. 
Irtutworlhij cement, as after a time it is readily loosened 
from its gronnd. It is, however, very useful for some pur- 
poses (gneh as " finishing" the slides), as it dries quickly. 
I shall, bowerer, mention a modidoation of this cement a 
little farther on. 

MiEINK Glue, — Uo cement ia more useful or trustworthy 
for certain purposes than this. It is made in various pro- 
portions; but one really good mixture is — equal parts of 
india-rubber and gum shellac; these are dissolved in mineral 
naphtha with heat. It is, however, mnoh better to get it 
from the opticians or others who keep it. It requires heat 
in the application, aa will be ouplained in Chapter V. ; hot 
is soluble in few, if any of the liquids used by the microscopist, 
&nd for that reason ia serviceable in the manufacture of 
cells, Ac. Where two pieces of glass are to be firmly 
cemented together, it is almost always employed ; and in all 
glass troughs, plates with ledges, &c., the beginner may find 
examples of its use. 

Gold Size. — This substance may always be procured at 
any coloarman's shop. The process of itii preparation is 
long and tedious. It is therefore not necessary to describe 
it here. Dr. Carpenter says that it is very durable, and 
may be need with almost any preservativB liquids, aa it is 
acted upon by very few of them, turpentine being its only 
true solvent. If too thin, it may be exposed for awhile to 
the open air, which by evaporation gradually thickens it. 
Oare must he taken, however, not to render it too thick, as 
it will then be useless. A small quantity should be kept on 
hand, as it is much more adhesive when old. 

GnH Dasimak Cejiekt.— An excellent cement may 1 


made bj dissolving gum dammar in benzole, and adding 
abont one-third of gold size : it dries very readily, and is 
especially useful when mounting objects in fluid, taking care 
that no moisture extends beyond the coYering glass, which 
would prevent the complete adhesion of the cement. In 
those cases where glycerine is employed as the mounting 
medium, a ring of liquid glue put round the cover first, and 
when that is dry, a second coat of gum dammar will keep 
the cover very secure, and no leakage take place. 

Liquid Glue is another of these cements, which is made 
by dissolving gum shellac in naphtha in such quantity that 
it may be of the required consistency. This cement appears 
to me almost worthless in ordinary work, as its adherence 
can never be relied upon ; but it is so often used and recom- 
mended that an enumeration of cements might be .deemed 
incomplete without it. Even when employed simply for 
varnishing the outside of the glass covers, for appearance's 
sake alone, it invariably chips. Where, however, oil is used 
as a preservative liquid, it serves very well to attach the 
thin glass ; but when this is accomplished, another varnish 
less liable to chip must always be laid upon it, (See 
Chapter Y.) Yet it makes excellent cells. 

Black Japan. — This is prepared from oil of turpentine, 
linseed oil, amber, gum anime, and asphalt. It is trouble- 
some to make, and therefore it is much better to procure it 
at the shops. It is a really good cement, and serves very 
well to make shallow cells for liquids, as will be described in 
Chapter IV. The finished cell should be exposed for a 
short time to the heat of what Is usually termed a " cool 
oven." This renders it very-tkirable, and many very cajreful 
manipulators use it for their preparations. 

Electeical Cement. — This will be found very good for 
some purposes hereinafter described. To make it, melt 
together — 

5 parts of resin. 
I „ beeswax. 
1 „ red ochre. 

OF mcBOsconc owecis, 47 

It mnst be nsed whilst hot, and as long aa it retains even 
slight warmth cSiTi be readily moulded into anj form. It is 
often emplojed is making ahalloir cells for hqniJj, aa before 

Grjt'WiTEB )B an article which nobody Bhould ever Uo 
without; but labelp, or indeed any sobatanoe, affiled to 
glass with common gam, are ao liable to leave it spon- 
taneously, especially when kept very dry, that I base lately 
added £ve or six drops of glycerine to an oance of the gam 
Bolntion. This addition has rendered it very trustworthy 
oven on glass, and now I never use it without. Ten grains 
of moist sDgar to each oance of gum solution will also 
answer eqnalty well. This solation cannot be kept long 
without undergoing fermentation, to prevent which the 
addition of a small quantity of any essential oil (as oi! of 
cloves, &c.), or one-fourth of its volume of alcohol, may be 
inade, which will not interfere in any way with its use. 

There is what is sometimes termed an exlra adhesive 
[fnm-water, which is made with the addition of isinglass, 
thns : — Dissolve two drachms of isinglass in four ouaces of 
distilled vinegar; add as mnch gnm arabic as will give it 
the required consistency. This will keep very well, but is 
apt to become thinner, when a little more gnm tnuy bo 

I may here mention that Messrs. Marion Imvo lately 
broaght out a cement for the purpose of mounting photo- 
graphs, which is very adhesive, eten to glass. I find it 
naeful in all case? where certainty is requisite ; as gnmmed 
paper ia liable in a dry piace to curl from tlie slides, as 
*ieibre mentioned. 

All these, eicept one or two, are liqoiil, and must be kept 
n stoppered bottles, or, at least, as free from the action of 
he air as possible. 

When any two substances are to be nnifed Brmly, I have 
termed the medium employed "a cement;" but often the 
Eppearance of the slides is thought to bo improved by 
Irawing a coloured ring npon them, eitending partly on the 


cover and partly on the slide, liidlng the junction of tlie twa 
The medium need in these casea I term a Tajikish, a 
heroin urtcr mention one or two. Of course, the tenocitj ii 
not required to be ao perfect as in the cements. 

Sealing-'VVax Vaekisb is prepared by coarselj- powder 
sealing-wax, and adding spirits of wine; it is then digested 
at a gentle beat to the required tbicliness. This is Teif 
fieqnentlj nsed to finish the elides, as before mentioned 
and can easily be made of any colour by employing diSereot 
liinda of aealing-wai; but ia very liable to chip 
leave the glass. The best qualitiea, however, will be lesi 

Black VA.E^"lSH — Is readily prepared by adding a amalt 
quantity of lampblack to gold-size and mixing intimatelj. 
Dr. Carpenter recommends this as a good finiahiug vamiBfa, 
drying quickly and being free from that brittleneas whicli 
renders some of the otliers almost worthless ; but it ahoold 
not be used in the first process when mounting objects u 

Amongst these different cements and varnishea I worVed 
a long time without coming to any decision as to thai 
comparative qualities, though making innumerable erperij 
ments. Tlio harder kinds were continually cracking, \ 
the Bofter possessed but little adhesive power. To fine 
hardness and adhesiveness united was my object, aad the 
following possesses these qualities in a great degree \— 

India-mbber J drachm, 

Aspbaltum 4 02. 

Mineral naphtha 10 „ 

Dissolve the india-rubber in the naphtha, then ad 
aspbaltum — if necessary, heat must be empluyod. 

Some scientific friends have complained that they have 
been unable to dissolve either the india-rubber c 
aspbaltum in mineral naphtha. The frequency with whieli 
I have seen this solution thoroughly accompHehed convince? 

OF mcBoscopio OBJECTS. 49 

me that one of tliese things baa occurred — either the india- 

Fmbber or the aBpliHltom has not been pare, or the naphtha 

' eon leoad iiiBtead of taineral. In the early photo- 

rapiiio dajB everj artist made a form of this varnisK to 

.ae with glass positives, and I never heard a complaint of 

This ia often need bj photographers as a bla.cb Tarnish 
IT glaas, and never crackii, nliilat it is very adbesive. Dr. 
brpenter, however, states that his experieoce haa not been 
tTODrable to it; bat I have used it in great qiiaatitiea and 
lave never found it to leave the glass in a single inatance 
rfaen used in the above proportions. The objections to it 
re, however, I think easily explained, when it ia known 
hat there are many kinds of pitch, &c., from coal, Bold by 
he n&me of asphaltom, eome of which are worthksa iu 
laking a microscopic cement. When used for this purpose, 
he tiBphaltnm moat be genuine and of the best qaality 
bat can he bought. The above niii:tare eervea a double 
inrpose — to unite the cell to the slide, and aUo as a "finiah- 
Dg " vamiah. But it is perhaps more convenient to have 
fro bottles of this cement, one of which is thicker than 
ommon varnish, to nso for uniting the cell, Ac.; the other 
quid enough to flow readily, which may be employed ae a 
NUrfaee varuiah in flniiihing the alides. 

The brushes or camel-hair pencils ahonld always be 
dwned after nse; hot with the asphalt varnish above 
bentioned it is anffioient to wipe off aa carefully as posaible 
2le snperflaous quantity which adheres to the pencil, aa, 
irhen again nsed, the Tarnish will readily soften it; bot, of 
tonrBe, it will be necessary to keep separate brashes for 
jbertain purposes. 

Here it may he observed that every ohject ahonld be 
labelled with name and any other descriptive item as aoon 
IB mounted. There are many little diflerences in the 
nethods of doing this. Some write with a diamond upon 
be slide itself; but this haa the disadvantage of being not 
S eBBlly Been. For this reason a small piece of paper _is 


usaallj affixed to one end of the slide, on wbich is written 
what is required. These labels may be bought of different 
colours and designs ; bat the most simple are quite as good, 
and very readily procured. Take a sheet of thin writing 
paper and brush over one side a strong solution of gum, 
with the addition of a few drops of glycerine, or grains of 
moist sugar, as above recommended ; allow this to dry, and 
then with a common gun-punch stamp out the circles, 
which may be affixed to the slides by simply damping the 
gummed surface, taking care to write the required name, 
&o., upon it before damping it, or else allowing it to become 
perfectly dry first. 

There is one difficulty which a beginner often experiences 
in sorting and mountiog certain specimens under the micro- 
scope, viz., the inversion of the objects; and it is often 
stated to be almost impossible to work without an erector. 
Bat this difficulty soon vanishes, the young student becoming 
used to working what at first seems in contradiction to his 

Let it be understood, that in giving the description of 
those articles which are usually esteemed necessary in the 
various parts of microscopic manipulation, I do not mean to 
say that without many of these no work of any value can 
be done. There are, as all will allow, certain forms of 
apparatus which aid the operator considerably; but the 
cost may be too great for him. A little thought, however, 
will frequently overcome this difficulty, by enabling him to 
make, or get made, for himself, at a comparatively light 
expense, something which will accomplish all he desires. 
As an example of this, a friend of mine made what he terms 
his " universal stand," to carry various condensers, &q, &c,, 
in the following way : — Take a steel or brass wire, three- 
sixteenths or one-quarter inch thick and six or eight inches 
long ; *' tap " into a solid, or make rough and fasten with 
melted lead into a hollow, ball. (The foot of a cabinet 
or work-box answers the purpose very well.) In the centre 
of a round piece of tough board, three inches in diameter, 

tcrs. 11 

snabe a hamiaplierieal cavity to fit balf of the ball, and bore 
a hole through from the middle of tKia cavitj. to allow the 
to paas. Take anoCher piecD of board, abont four inches 
in diameter, ei'her roand or aquarp, and one and a half or 
two inches thick, make a eioiilar cavitj in its centre to 
a the other half of the ball, bat only bo deep as to 
the ball to fit tightly when the two piecea of board 
rewed together, nhich last operation mtiat be done with 
or four BcrewB. Let the hole for the wire in the upper 
part be made conical (baae opwards), and so large as ouly 
to prevent the ball from escaping from ita socket, in order 
that ibe shaft may move ahiut as freely as poaeiblo. Turn 
cavity, or make holes, in the bottom of the Doder piece, 
>d fill wiih lead to give weight ani eteadineaa. Thl?, 
painted green bronze and varniahed, looks neat; and by 
having piei^es of giilta-percha tabiag to fit the ahafl;, a great 
Tftriety of apparatns may be attached to it. 

Mr. Loy employs the following arrangement for diaseotinf; 
insects or picking ont Poraminifera, &a. : he fits an upright 
brass rod into a heavy leaden foot, this rod carries a hori- 
Eonlal arm bearing at ita end a ring for holding a watch- 
maker'a eye-glass; in foaussing it to hia work, he presses 
the eye-glass down with his head, the weight of the ItaJen 
foot^ keeping it in its place, and allowing it to follow hia 
every movement. 

Agaio, a " condenser " ia often required for the illomina- 
tioD o( opaque objects. My ingenioua friend uses an 
"engraver's bottle" (price 6d.), fills it with water, and 
BDSpends it betwiiit the light and the object. Where the 
lijjht ia very yellow, he tints the water with indigo, and ao 
removes the objectionable colour. 

I merely mention these as ciamplea of what may he 
done by a little thoughtful contrivance, and to remove the 
idea tbat nothing is of much valne eave that nhich ia the 
work of profeasioDBl workmen, and consequently expensive. 




The term " dry" is used when the object to be moanted is 
not immersed in any liquid or medium, but prefseryed in its 
natural state, unless it requires deaniug and drying. 

I have before stated that thorough cleaDlioess is necessary 
in the mounting of all microscopic objects. I may bere add 
that almost every kind of substance used by the microscopist 
suffers from careless handling. Many leaves with fine hairs 
are robbed of half their beauty, or the hairs, perhaps, forced 
into totally different shapes and groups ; many insects lose 
their scales, which constitute their chief value to the micro- 
scopist ; even glass itself distinctly shows the marks of the 
fingers if left uncleaned. Every object must alno be 
thoroughly dry, otherwise dampness will arise and become 
condensed in small drops upon tbe inner surface of the thin 
glass cover. This defect is frequently met with in slides 
wbich have been mounted quickly; the objects not being 
thoroughly dry when enclosed in the cell. Many cheap 
slides are thus rendered worthless. Even with every care 
it is not possible to get rid of this annoyance occasionally. 
A good plan is to fix the covers on to the cells temporarily 
by dropping on two sides of them a composition of equal 
parts of wax and resin : this allows of the easy removal of 
the cover at any time, while the object thoroughly dries 
and is protected from dust and damage. 

For the purpose of mounting opaque objects " dry " 
discs were at one time very commonly used. These are 
circular pieces of cork, leather, or other soft substance, from 
one*quarter to half an inch in diameter, blackened with varnish 

or HicaoscoFic ouects. £3 

or cavcred with black paper, on whiob the abject is &xt<i bj 
gnm or eome other adbrsive Babstance. Tbej are oauallj 

]iiereed loDgituJinally b; a strong pin, which aervea for the 
forcepa to laj hiiid of when being plaoed under the micro- 
scope for examination. Sometimea objects are affixed to 
both Bides of the diso, nhich ia readilj tnined vhcn under 
the objtfct- glass. The advantage of Ihia method of mount- 
ing ia the ea^e with nhich the disc ma; be moved, au>I so 
preeent every part of the object to the eye, fflive that by 
which it ia fastened to the disc. On this account it is ot^en 
used when some particular subject is undergoing iinestigft- 
tioQ, aa a number of specimens may bo pWcd upon the 
discs with very little labour, displayiog all tlieir parte. But 
where eiposnre to the atmosphere or small partiuica of duat 
will injure an object, no advantage nlitch dmcs may possess 
should he considered, and an ordinary covered cell ahonld 
be employed. Small pili-boxea have been used, to the l>ot- 
torn of nhich a piece of cork haa been glued to alTord a 
ground For the pin or other aiaSe of attachment ; but this 
ia liable to scim« of the aame faults aa the diac, and it would 
be nnwiae to use these for permanent objects. 

Ueaara. Smith and BkcIi have lately invented, und are 
noir making a beautiful small apparataa. by means of 
which the diac supporting- the object can be worked with 
little or no trouble into any position that may prove moat 
ooQTenient, whilst a perforated cylinder aerves for the ri:cup- 
tioB of the diaca when ont of uae, and fits into a oa«e tO 
protect them from dust. A pair of forceps ia made for the 
express purpoae of removing them from the onsa and placing 
tliem in the holder. 

All dry objects, however, which are to be preserved should 
1m moauted on glass slides in one of the cella (described in 
Chapter II.) best suited to them. Where the object is to be 
free from pressure, care must be taken that the cell is deep 
enoogh to enaure this. When tbe depth required is but 
■mall, it ia often sufGciont to omit the card, leulher, or 
oth«r circlea, and with the " turntable " before described by 


means of a thick varnisli and camel-liair pencil, to form a 
ring of the desired depth ; bat should the yarnish not be of 
sufficient substance to give such *' walls " at onne, the first 
application may be allowed to dry, and a second made upon 
it. A number of these may be prepared at the same time, 
and laid by for use. When liquids are used (see Chapter V.), 
Dr. Carpenter recommends gold-size as a good varnish 
for the purpose, and this may be used in dry mountings 
also. I have used the asphaltum and india-rubber (men- 
tioned in Chapter IL), and found it to be everything I could 
wish. The cells, however, must be thoroughly dt-y, and when 
they will bear the heat they should be baked for an hour at 
least in a tolerably cool oven, by which treatment the latter 
becomes an excellent medium. All dry objects which will 
not bear pressure roust be firmly fastened to the slide, 
otherwise the necessary movements often injure them, 
by destroying the fine hairs, &c. For this purpose thin 
varnishes are often used, and will serve well enough for 
large objects, but many smaller ones are lost by adopting 
this plan, as for a time, which may be deemed long enongh 
to harden the varnish, they exhibit no defect, but in a while 
a ** wall " of the plastic gam gathers around them, which 
refracts the light, and thus leads the student to false 
conclusions. In all finer work, where it is necessary to 
use any method of fixing them to the slide, a solution of 
common gum, with the addition of a few drops of glycerine 
(Chapter II.), will be found to serve the purpose perfectly. 
It must, however, be carefully filtered through blotting- 
paper, otherwise the minute particles in the solution interfere 
with the object, giving the slide a dusty appearance when 
under the microscope. 

When mounting an object in any of these cells, the glass 
mnst be thoroughly cleaned, which may be done with a 
cambric handkerchief, after the washing mentioned in Chap- 
ter II. If the object he large, the point of a fine camel-hair 
pencil should be dipped into the gum solution, and a minute 
quantity of the liquid deposited in the cell where the object 


be plaaed, but not to cover a greater surface tbaa the 
object will totally hide from eight. This drop of gum must 
be allowed to dry, irbi^h will take a few minutes. Breatlie 
then upon it two or tbree timea, holding the elide not far 
from the month, which will render the surface adheBive. 
Then draw a, camel-hair pencil throutjb the Hpa, bo aa to 
moistea it Blightly (when anything small will adhere to 
it quite firmly enoagh), tonch the object and place it 
npoQ the gum ia the desired position. This must be dona 
immedialely to ensure perfect stability, oilierwiae the gnm 
will become at least partially dry and only retain the object 

When, however, the olijects are bo minnfe that it would 
! be impossible to deposit atoms of gum amall enongh for 
each one to cover, a. different method of proceeding must be 
adopted. In this case a BmuU portion of Iba same gum 
solution ahonld be placed npon the slide, and by means of 
any email inatvoment — a long needle will serve the parpoae 
Tery well — spread over the surface which will be required. 
The quantity thus extended will be very small, but by 
treatbing npon it may be prevented drying whilst being 
dispersed. This, like the forementinoed, should be then 
I allowed to dry; and whilat the olijects are being placed on 
the prepared surface, breathiog upua it as before will restore 
the power of adherence. A small patch of gold-si^.e — -or 
gam dammar aolution which has been allowed to became 
"taekey" — la very uaeful in many caaes. 

When gum or other liquid cement baa been used to fis 
the objects to the glass, the tbio coverfl must not be applied 
until the slide has been thvTOugldy dried, and all fear of 
dampness arising from the use of the solation done away 
with. Warmth may be safely applied for the purpose, aa 
olgeots fastened by this method are seldom, if ever found to 
be loosened by it. As objects are rnet with of every tbicli- 
nesa, the cells will be requirnd of different depths. There 
18 no difficulty in accommodating oursdves in this — the 
deeper cells may bo readily cut out of thick leather, card, or 


other snbstance preferred (as mentioned in Chapter II.)* 
Cardboard is easily procured of almost any thickness ; bat 
sometimes it is convenient to find a thinner substance even 
than this. When thin glass is laid upon a drop of any 
liquid npon a slide, every one mast have observed how 
readily the liqaid spreads betwixt the two : jnEt so when 
any thin varnish is nsed to snrroand an object of little snb- 
stance, excessive care is needed lest the varnish shonld 
extend betwixt the cover and slide, and so render it worth- 
less. The slightest wall, however, prevents this from taking 
place, so that a ring of common paper may be used, and 
serve a double purpose where the objects require no deeper 
cell than this forms. 

Many objects, however, are of such tenuity — as the leaves 
of many mossep, some of the DiatomacesB, scales of insects, 
&o. — that no cell is requisite excepting that which is neces- 
sarily formed by the medium used to attach the thin glass 
cover to the slide ; and where the slide is covered by the 
ornamental papers mentioned in Chapter IL, and pressure 
does not injure the object, even this is omitted, the thin 
glass being kept in position by the, cover ; but slides mounted 
in this manner are frequently injured by dampness, which 
soon condeoses upon the inner surfaces and interferes both 
with the object and the clearness of its appearance. 

The thin glass, then, is to be united to the slide, so as to 
form a perfect protection from dust, dampness, or other 
injurious matter, and yet allow a thoroughly distinct view 
of the object. This is to be done by applying to the glass 
slide round the object some adhesive snbstance, and with the 
forceps placing the thin glass cover (quite dry and clean) 
upon it. A gentle pressure round the edge will then 
ensure a perfect adhesion, and with ordinary care there will 
be little or no danger of breakage. For this purpose gold- 
size is frequently used. The asphalt and india-rubber 
varnish also will be found both durable and serviceable. 
Whatever cement may be used, it is well to allow it to 
become in some measure fixed and dried; but where no 


■ wall ia npon the elidp, this ia quUe neeegsaiy, 
otherwise the varniah will be mnst certain to estend, as 
before mentioDed, and rata the object. It may be stated 
I that gold-size diffdra greatl; in ita drring powers, 
Bccordiug to ita age, mode of preparation, &::, (Chapter Y.) : 
liere gum dammar Rolntioii laid od ia a verj thin coating 
will be foond moat n^erul, aa it dries so rapidlj ibat it caauot 
an in Dnless laid on nilh an nufiparicg band. 

Shonid any object be encloaed nbich reqairea to be lept 
fiat dariog tbe drying of the cement, it wilt be ueceiiaarj to 
e of tbe contriTances mentioned iu Chapter 11. 
1 tbe slide is thas far advanced, there remains the 
finiahing only. Should tbe atuJenf, however, have no 
time to complete bia work at once, be may saMy leave it at 
this stage nntil he have a number of slides which be may 
fiaisU at the same time. There are ditferent methods of 
> doing thia, some of nhich may he here described. 

If ornamental papers are preferred, a small circle mnat 
be cut ant from the centre a little lens that) the thin glass 
which covera the object. Another piece of coloured paper 
18 made of tbe same size, and a similar circle taken from ita 
centre alao, or both may be cut at the same time. The 
, ilide ia then covered roond tbe edges with paper of any 
pluD coloor, BO that it may extend about one-eigbtb of an 
inch over the glass on every side. Tbe ornamental paper 
ia then posted on tbe " object " sarfaee of the glaaa, so that 
the circle shows the object aa nearly in tbe centre as ponaible, 
and covers tbe edt;ea of the thin glass. Tbe other coloured 
paper ia then a£ied nnderneath with the circle coinciding 
■with that above. And here I may observe, that when this 
method ia need there is no necessity for the edges of the 
■lide to be groond, as all danger of scratching, &c., is 
obiritttcd by the paper cover. 

Many now nse paper oovers, abont one and a half inch 
long, on the upper side of the slide only, with the centre 
cat out aa before, with no other pnrpoue than that of 
hiding the edge of tbe thin glass where it is united to the elide. 


The melbod of fi.aifili!ti^, however, trhich ia moatlj used 
6.i the [ireaetit time, ie to laj a coating of varnish upoa tha 
edge of the Ihin glaaa, and extend it some little way on the 
alide. When a black circle ia reqaired, nothinff acrves the 
purpose bett«r than the goU-siza and lampblack, or tiifl 
BBpbalt and inditi-rubber TartiiHh, neither of which ia liabla 
to chip; but nhen uaed for thia. the lutler aboald be rather 
thinner, aa bsrore adviaed. Soriie of these varaishea ara 
preferred of different colonra, which loaj be mai'e by using 
the different kiniia of aeHliu[{-wai, aa described in Chapter II.; 
but they are alnaja liable to the dufucts th-re meutiooed. 
' Tbia oiruls cannot be mude in any other nay than by one of 
thoae coatrivancea called torntablea. A very litde praotioe 
wilt enable the young student to place his slide eo that tlia 
circle may be nuiform with the edge of the thin glaaa. 

The alide ia now conipletp, except the addition of tlie 
name and any oiher partlculHra which may be desirable. 
For this purpose one of the methoda deacribed in Chapter XL 
must be employed. 

Amongst the various claaseB of microscopic objects noir 
receiciog general attention, the DlatomacPSB may ha plooed 
in a prominent position. They afford endlesB opportnnitiM 
of rcBearch, and some very eldborate worta have already 
been isHoed concerning them. Professor Smith's may lie 
mcntion<;d as one aontaioing, perhaps, the beet illustratioiia. 
The yniing atadent may wish to know what a diatom ia. 
The ''Micrograpbic Diclionarj" gives the foUowiog defi- 
nition; — "A family of confervoid AlgEB, of very pecnliu 
character, eonsistio^ of microscopic brittle organlBOiB." 
They are now looked upon by almont all of our acientifie 
men as belonging to the vegetable kingdom, though some 
few still af'Hign them to the animal. They are almost 
invariably bo exceedingly email, that the anaided eys oan 
perctivB nothing on a prepared slide of these orgaoisma but 
minute dnst. Each srparate portiou, which ia usoally seen. 
when mounted, is termed a "frustule," or " tectiile :" this 
consista of two bimilar p&rta, composed of silica, between and 


BOmetimea around whieh, is a mass of vistid matter ailed 
the " eadochrome." Thej are found in almost every doaerip- 
tion of water, according to the varietj; some prefer Bfla- 
vater, others fruah, and manj are eeen nowhere liut !□ tbat 
vhich is a mistiire of both, as the luocths of rivers, &e. 
Ditches, ponds, cisterns, and indeed almost everj reservoir, 
jfield ahoodance of these forms. They are not, however, 
confined to "present" life; bat, owing to the almost in- 
deetructible nature of their eilJceoua coveriog, they are 
found in a fossil atate in certain earths in great abundance, 
and are often termed " fossil Infasoria," Upon these frua- 
tnles are generally to be aeea lines, or markings, of 
different degrees of minuteness, the delicacy of which often. 
BBrvea the purpose of testing the deBning power of object- 
glasses. Some of the frustules arc triangular, others circular, 
and, indeed, of almost every conceivable shape, many of 
them presenting us with exquisitely beautiful designs. 

Tbe markings, however, are seldom seen well, if at all, 
until the frustulea are properly prepared, the differeot 
methods of accomplishing which will be givea a little 
farther on. 

The collection of fresh diatoms is so closely connected 
with, their preservation, that a few notes may be given opoii 
it. before vie pass on. For this purpose a number of small 
bottles mnst be provided, which may be placed in a tin box, 
with a separate compartment for each, so that all chance of 
lireakage may be done away with. The diatoms are generally 
of B. light brown colour; and where they are observed in the 
water, the bottle may be so plated, with the moulh closed 
by the finger, that when the finger is withdrawn the wat«r 
will rush in, carrying the diatoms also. If thej are seen 
upon plants, stones, or any other substance, they may 
generally be detached and placed in the bottle. When 
there is a green covering npon the surface of the water, a 
great quantity of diatoms is usually found amongst it; as 
also npon the surface of tbe mud in those ponds where they 
abound. In these cases, a broad fiat spoon will be found 

CO rnEPiHiTiON *SD siocnting 

yery nBefnl, and one U now made with a wiTeriog npon Iha 
liroader portioa of it to protect the eoclosed matter from 
Wag BO readily carried dIF whilst bringing it to the s- 
again. Where there ia any depth of nater, and the spoon 
will not reach the sarface of the mud, the bottle must be. 
united to a long rod, and being then carried through Ihs 
upper portion with the oiouth downwards, no water will bc 
received into it; bat on reaching the spot required, :' 
bottle-mouth may be tnrned ap, and thus become tilled witll 
what IB nearest. 

Prom tbe storaacba of common fish — as the cod, eole, hadf 
docb, &a. — many specimens of Diatomaccaj may be obtained 
but eepecially frnm the crab, oyster, mussel, and other si 
fish. Professor Smith states that from these cnrii 
tacles be hail taken some with which he has not elaewha 
met. To remove them from any of the small shell-fish, it i 
neoesaary to take the fish or stomach from the shall, m 
immerse it in strong hot auid (nitric is the beat) until tl 
animal matter is disBolTed, when tbe residue mnst 
washed and treated as the ordinary Diatomaccco hereinafbi 

Many diatoms are Been best when mounted 
state, the raiuute markings becoming moch more indistioi 
if immersed io liquid or balsam; and for this reason th 
which are used as teat objects are nsnally mounted o 
Many kinds are also now prepared in this way aa opaqi 
objects, to be examined with the lieberknhn, and ara ■ 
quisitely beantiful. Others, however, are almost invarial 
mounted in balsam ; but as these will be again referred I 
in Chapter IV., and require the same treatment to fit the) 
for the slide, it will not be out of place to describe t' 
cleaning aad preparation of them here. As before stati 
there is miich matter surrounding them which mast 1 
got rid of before the iiliceous covering caa be show 
perfectly. As, however, we may first wish to becon 
acquainted in some degree with what we have to do, it : 
well to take a small piece of talc, and pluce a few of th 

or MiCBoscoric objects. ^1 

o it. TliiB may be teld over the flwno of Ui« 

■^rit-lamp until mil tie snrroandicg matter is hnrnt avay, 
aitd A tolerable idea may Uiub be obUuned as to tliii iiuditjr 
r treasore. 

Mm« cases it ia well to ttse tbis barnioff 0|)«ration 

■lone in mcunting specimens of diatoms, when thej luaj bo 
placed in tbeir natural state upon thin glass, burnt for 
airhile upon the platinam plate, heretnaftei' d<iscrib«tl, and 
motinted dry or in balsam. 

In the preparation and cleaning of Diatoniaoew, tlioro js 
little satisfaction unless these operatiooa bavo boon suooras- 
fttUy performed, as a very email portion of foreign matter 
serionely interferes with the object. The mode of proparinK 
them varies even amongst the most experienced. It will ho 
fbnnd, therefore, moat Batisfaotory to examine tho prinolpal 
of these separately, although it may be at the risk of sumo 
little repetition. 

The method which ia moet freqnontly employed is the 
following; — Place the gntheriog oontaiiiiiig the Dinto- 
macece in a small glues or porcelain Teenol, add strong 
nitric acid, and, by the aid of a Bunaen's burner or spirit' 
lamp, boil for some minuteH. From time to time a drop of 
the mixture may be put open ii slide, and examined uiidor 
the microscope to see if all foreign matter bo got rid of, 
When the ralves are clean, the vessel contuiuing thpm must 
be filled with water, and the whole left fur an hour or two, 
BO that all the diatoms may boIUb perfectly. Tho liquid 
mnst then be poored off carefully, or drained away by the 
■jd of a Bj-pbon, so that none of the diatoms are ramovod 
with it. Indeed, it is well to examine the liquid drsined oft 
each time with the microsccpo, as tho finer forma aro 
frequeutly lost in the washings. The vei^sol most th*n be 
refilled with pure water, allowed to settle, and drained aa 
before. This washing must bo repeated until a drop befng 
placed opon a slide and evaporated leaviai no etjmUU, 
When it is desirable to preserve the diat/jms in thia atat* 
Woie moantiog (which proceai will be described in aootJ 

plact'), they maj be placed in a amall phial with a litthl 
diatilled water. 

There are many caaea in whiah the shore method will n 
eOect a perfect cleaDsing, as certain gnhatances with whl 
diatoiDs are frtiqaently mixed are not soluble in nttrti: ne\ 
For thia reaflOD the following method ia reenrted to :— Ta 
a qaantitj of the matter containiiig the Diatomaceis ana 
wash first with pare water, to get rid of all the impnritid 
poaaible. Allow this to sellle perfectly and decant tba 
■water. Add hjdrochlorio aoid gradually, and when alt 
eServeaccnce has sobsided, boil for aome minDtcs hy aid oi 
the lamp. Wben cool and the particles have sabBtdecl 
decant the hydrochloric and add nitric acid. Tbe boilinj 
mnat then be repeated until a drop of the liquid whet 
placed nnder the microscope shows the tbItus or " frnatnleH' 
clean. After allowing tbe diatoma to settle, the aoid n 
he decanted, and pure water anbatituted. Tbe waahinj 
mnat he repeated aa in the former proceaa until all t 
lemains of crystals or acid arc removed, when tbe apecimenj 
may be preserved in amall phials. 

Snch are the nenal modea of treating the Diatomacefla 
hut there are certain cases in which particular methods ar 
required to give anything like perfect naults. Persons a 
great experience combine a variety of treatmenta, and thw 
obtain better and more nniform apecimens. Perhaps it wil 
he advantageous to give the yonng atudent the proces 
adopted by one of the moat saoceBsfol preparers of f 
objeota ; but I will Brat state the different methods a 
mounting the cleaned diatoms dry : how to employ Canadt 
balsam and fiuid in their preaervation will be elsewhert 

It was before stated that diatoms when cleansed migh 
be preserved in small pbials of distilled water. When 
quired for monnttng, shake the phial, and with athin glaa 
tube or rod take op a drop of the Suid and Bpread it npol 
the snrfnce of the alide in tbe desired position. Thii 
then be allowed to dry gradually, or by the aid of tbe lsin| 

itiioat being shaken or iaterrered with, otlier- 
wise Dniformity of dispersioo will be prpveoteii. When 
titorougMy d'j, a thin ring of one of the adhenife varnirhea 
' — gold-^ise will be round as good as ao; — 'oaj "be druwn 
ronnd the djatomR, and allowtd to drj in a slight degree. 
The slide and tbio glass cover should then be warmed and 
the latter gentlj pressed opon the riog of TarQisb aotil iha 
BdhesioD all round is cotDplet«. 

As some of the diatoms require object- glasses of eitremely 
high power, and cnaeqDeDtlj short focos, to show them, 
they mnst be an close to the onter sarfaee of the cover aa 
possible. For this reasoD thej are BOmetimes placed upon 
the nnder side of the thio glass, aa follows. Clean the 
BQifacee of the elide and cover, and with the rod or pipe 
place the liqnid containing the diatoms upoo the thio g'ass, 
and dry as beFore. Trace the ring to receive the cover upon 
the slide, and when almost dry. warm both and proceed as 
■.bove. Whichever of these methods is employed, the outer 
ring of coloured varnidh may be applied as elsewhere descrilwd 
and the slide finished. 

Diatoms are also sometimes mounted betwist two thin 
glasses, as deacribed in Chapter II.. so that the light by 
vhiah they are examined njay receive as little interference as 
poaMble, and that an achromatic condenser may be brooght 
into focns under the slide. 

Of the various modes of cleaning and moanting Dinto- 
niacero, I believe that the following may be safely recom- 
. mended, as affording results of the bent quality. My friend, 
I Mr. T. O, Bylands, gave it to me as that which he prefers, 
and I can salcly say that his numerous slides are at least 
equal to any I have ever aeen. I will give it just aa I 
received it from him, though there may be some little 
repetition of what has been said elsewhere, hb he does not 
appropriate any part of it as his own. He says ; — In this 
branch of mountini;, general rules alone can be laid down, 
because the gatherings may contain iron, lime, fine silt, or 
vegetable matter under conditione for special treatment, and 

I ; 


cotiaeqacntlj the first step shonld ba to experiment on 

Id leathering diatomE raDch laLonr is saved by jndgmeBl 
and care; hence il is desirable to get acqnaiuted with then 
in their growiD^ conditioD, ao that when recognised npa 
the sand or otber spotfl, thej maj be carefnllj remavecl fa 
the aid of the spoon or small tin scoop before deaoribet 
When growing upon algiB or other plants, the plante ui 
diatoms together ma; ha carried home, in nhich case thi^ 
mntit be simplj drained and not nashed or pressed, in ordfl 
that the diatomn be not lost. As it is atwajs desirable t 
examine the gathering on the gronnd, a " Gulrdner's hftm 
micro B cop e " with powers from 80 to 200 diameters will b 
fonnd very useful. The beat gatherings are those whid 
represent one species abundantlj. Those which are nixei 
maj be rfjected, unless they are seen to contain somethiog 
falaahle or important, as the object shonld be not so mnci) 
loBopply microBCopical curiosities as to collect material whioh 
is availsbte for the study of nature. 

The gathering when carried home should always he (i 
fnlly Biamined before anything ia done with it ; not only oft 
account of the additional information thns acqnired, bnl 
also because it often happens that a specimen sboiild b 
mounted in Quid (see Chapter Y.) in the condition in whiol 
it is gathered, as well as cleaned and mounted in ball 
(Cbspter IV.) and dry. 

Where the gathering ia taken from sand, the whole it 
be shaken up in water as a preliminary operation, whel 
much of the sand will be separated bj its own weight. Thi 
lime test, however, should be applied; viz. — a small pottim 
of hydrochloric acid, aod if there be effervescence, it most bl 
dissolved out by this means. From Algie and other wee 
diatoms may be detached by agitating the whole t«getfa« 
wealc solution of nitris acid — about one of pare acid to 
twenty or thirty of water, as it must be sufSciently weak to 
free the diatoms without destroying the matter to which 
they adhere. The diatoms may then be separated by 

ECTS. 65 

Bifting thtOQgh coarae muslin, which will retain the Algm, 
&a. The prOBesa of cleaning will vary aocordiog to circom- 
BtaooeB. Some gatherings rec[iiire to be boiled only a few 
mittuteB Id nitric acid; but tiie more general plan, where 
they are nixed with organic or other foreign matter, is to 
hoil them in pare salphurio acid until they cease to grow 
darter in colonr (usually from a half to one minate), and then 
to add, drop by drop to avoid eiplosioaa, a cold saturated 
Bolntion of chlorate of potaah nntil the colouris disobftrgea, 
or, in cose the colour does not disappear, the quantity of 
the Bolntion need is at least eqaal to that of the acid. 
This operation is beet performed in a wide-mouthed ordinary 
beaker glass,* a test-tube being too narrow. The mixture 
whilst boiling should be poured into thirty times its bulk of 
cold water, and tho whole allowed to subside. The fluid 
most then be carefully decanted and the vessel re-Buppli«d 
once or twice with pure water, ao as to get rid of all the 
acid. The gathering may then he transferred to a smalt 
boiiing-glass or test-tube, and — the water being carefully 
decanted — boiled iu the a mall est available quantity of 
nitric acid, and washed aa berore. Thia laat process has 
been found necessary from the frequent appearance of 
niinote crystals, which cannot otherwise be readily dis- 
posed of without the loss of a considerable proportion of 

I may here mention that the washing-glaaaes used by 
Mr, Rjlanda are stoppered conical bottles varying in 
capacity from two ounces to one quart; the conical form 
being employed to prevent the adherence of anything to the 
side ; they are stoppered, to render them available in the 
shaking process about to be described. 

The gathering, freed from acid, is now put into two inches 
depth of water, shaken vigorously for a minute or two, and 
allowed to subside for half an hour, after which the tuibiJ 

* Ttieia glBEaee are round, atiDut six inches high, and usnally contain 
about eight ounces. Tlis; are rather wider at the bettuui, tapering 
gradually to t^ top, and may be generally procured at the chemists, do. 



fluid iniiat be care fullj decanted. This operation mnet Iw 
repeated until all the matter is removed nhicli will not 
settle in half an honr. The fluid removed ehoold be ei* 
amined by a drop being put upon a slide, aa in some 
very light diutoma have been found to come off almoat 
pare in one or more of these earlier waibings. The quan- 
tity of water and time of sabsideuce giveu may be taken 
generally, but may reqaire to be modified according to 
rircumstances and the judgment of the operator. By th» 
repetition and variation of this proceBS — the akakiny hwtgi 
the moat important part — the gathering, if a pwre one, will 
ifficientlj clean. If, however, it contain a variety <^ 
ipeciea and forma, it may reqnire to be divided into differerd 
den fU if a. 

le oases, however, it ia beat to divide the gathering 
as A preUminary operation, which may be done by s^tating 

in a qnantity of water and decanting what does i 
readily anbaide. The heavier and the lighter portions ara 
then to be treated as two aeparate boilings. Bat when tb^ 
cleansing has been carried to the above stage and thit 
division ie required, the plan most be somenbat as follows : — 
The gathering mnst be Bhalen in a test-tvbe with six inohOI 
of water, and then allowed to eubside until one iach at the 
top remains pure. About three inchca are then to be care- 
fnlly withdrawn by a pipette, when the tube may be fillrft 
up and the operation repeated. The three lower inches e^» 
may then be decanted and examined. Tbe gathering i 
thus divided into three portions; viz. — that which w» 
withdrawn by the pipette, that which remained floating 
in the lower three inches of water in the tnbe, and! 
that which bad settled at the bottom. An examination of: 
these will inform tbe operator how to obtain that partienlar 
density of gathering which he desires, and how far it il 
wQrtk while to refine thia procesa of elutriatiau ; li 
cases of neuesRity any one, or all three, of these densititt 
may be operated upou in the same way to separate b 
particular diatom. 

0? Micaojcopic OBJXCTS. 67 

Aa an occasional aid, it may be remarked, tliat io some 
casea liquor ammoiii^e may be nsed io one of tlte later 
^aahinga in place of water, aa it often Beparatea fine dirt, 
-wbtcli is not otberwiBe easily removed. Ammonia aleo dis- 
solves R BoccnUot matter whicb iometimea remains ; and 
tbia method does not injure diat«tas like some «troDg alkalies. 
Some foasil deposits require to be treated with a boiling 
eolntion of carbonate of soda to disintegrate them ; bat 
this operation reqnirea great care, lest the alkali ahontd 
deatroy the diatoms. Yegetable ailicatcs also sometimes 
require to be removed by a aolotion of carbonate of soda; 
bnt as the frnstulea of the diatoms themaelvea are bnt 
vegetable silka, even more care is required ia tbia case. It 
may be well to mention, that some diatoms are so imperfectly 
ailiceons that they will not bear boiling in acid at all. Soma 
of tbese may be allowed to stand in cold nitric acid some 
time, whilst others of a smaller and more delicate character 
should, when possibie, bo treated with distilled water 

We will now consider the mode of monnting the prepared 
diatoms, which, if nsed dry (aa described in this chapter), 
Bhonld be carefolly washed two or three tlmea with the 
pnrest distilled water. In this branch, as in ever; other, 
each collector gives preference to that method in which he 
is an adept. Thus the diatoms may be placed on the 
nnder side of the cover, to be as near to the object-gUas 
as possible, or npon the slide itself; and each plan has 
its adrocates. Whichsoever of these is nsed, nothing seems 
more simple to the novice than a. tolerably equal dispersion 
of the objecta opou the slide or cover ; but this is by no 
means ao readily accomplished; coDEcqnently I give Mr. 
Bylands' method, as his slides are perfect in thia respect 
also. He always places the diatoms upon the thin glass 
cover. It is not sufficient, aa is freqnently thought, to 
take a drop of liquid containing the cleansed material and 
spread it npon the cover or slide, as without some additional 
precaution that uniform and regular distribution of the 

63 FBEF^XA.Tios AXD liovsTisa 

specimens, which ia deiirablp, 19 not obtaioed. In order to 
effect this, let a drop of the cleanced gathering be dilnt«d 
lufficifotlj for the porpose — hot* macb must be deteriniiied 
in each ease bj experiment — and let the covers to ba 
Tnoanted be cle&ued and liud upon the brass plate. (9f 
Chapter IL) By means of a glass tube, abont one-twelfth of 
an. inch in diameter, stopped by the wetted finger at ths 
upper end, take np as mnch of the dilated material as wiQ 
form a moderately conres drop eitending over the whole 
cover. When all the coverB required are thaa prepared, 
apply a lamp belotr the brass plate, and raiee the tent' 
peratnre to a point jnst short of boiling. By this meant 
the covers will be dried in a few minutes, and the specimena 
eqoally distributed over the whole area. The spread of' 
the Said npon the covers is facilitated by breathing npoa 
them ; and, to insure oniformity, care mnst be takea to 
avoid shaking them whilst drying. The beat pit 
mount at least half a dozen at once. 

Before mounting, Mr. Aylands always bums the diatom^ 
npon the glass at a dull red, whether they are nsej 
with balsam or dry. This burning, he saya, is not only 
an additional cleaning process, bnt it effectually fixee the 
diatoms, and prevents them floating out if moanted mtll 
balBam. The thinnest covers may be bnrnt without damag 
if they are placed npon a small piece of platinam foil ( 
the size required, which should be about one-hundredth ( 
an inch thicb, perfectly flat, and having three of its edge* 
slightly bent over, so ae to prevent its warping with th^ 
heat. The graall flame of a spirit-lamp, or, where ther" '"" 
gas, a Bunsen'R burner, may be employed. The 1 
should be shaded from direct daylight, that the action t 
the flame may be obaerved more perfectly. Care must then 
be taken to raise the temperature only to the dull red heat 
before mentioned. The cover will then be in a fit state fl 
moan ting as required. 

It has been stated in another place that it is assnoied 
that the operator is not mounting diatoms simply aa □ 

n t4 

or siicBOsconc objects. C9 

e«pic objects, bat as iustractive Fpecimecs. It i« not, 
lltirref<are, enfficient to lai'e a EiGgle elide as all tJiat is 
reqnired, but to bave tbe sajne diatom prepaied in as manj 
ways BH poMible. Tbe following are tbe principal: — 

1. Itoanted crude in fluid (see Chapter T.) 

2. Burnt cmde apon tbe cover, and muncled drj or in 

3. Mounted drj or in balsam (see Chapter IV.), after 

the cleansing prooesa alreadj described. 

I will brre give Mr. fijianda' method of mounting tbem 
{try, the Said and balaam preparations being noticed in 
Iheir respective chapters. Tbe slide, with the ring of 
asphalt, or black TaraiEh, should bave been prepared soma 
weeks previously, in order to allow it to dry thoroughly. 
When required, it must be held over tbe spirh-lamp or 
SuDsen's burner until the ring of varniab is softened. The 
bamt cover, having been heated at tbe same time, must 
then be taken in tbe forcepa and pressed upon the softened 
vamiBb DDtil it adhere all round. When cold, an outer 
ring of asphalt completes the elide. 

Saob is tbe method which my friend Mr. T. G. RyUnda 
employs in the preparation of diatoms for the microscope. 
I bave said enough concerning his resnlts. It is to be 
feared, however, that to some these several modes of opera- 
tion may appear lengthy and complicated ; but if read 
carefully, and the experiments tried, they will be found to 
be simple enough in practice, and to occupy much less time 
than an intelligible description would lead the novice to 
believe necessary. 

The minute nature of diatom forms, and tbe high micros- 
copic powers by which they are eiamiuad, render a very 
shallow cell necessary when they arc mounted upon a dry 
slide. Many early atitempts, on this account, have been 
ruined by tbe cement used to fix the thin cover tiproading 
underneath. A correspondent of the " Monthly MicroBOopio 
Journal " thus gives his mode of avoiding this : — " There it 
a very simple means of avoiding this danger, and I will 


now deecribi) it. A oirele of bituman about one third 
Bmaller than the coveriog glasa ia drawn befarehai 
slides. When I wish to maka a preparailioo, instead c 
GoattDg, a9 formerly, the first circle with a aecotid lajer 
bitniueo, I form a aecood circle of it ootside the first, and 
as Dear as posaihle to it, and each of the two cirolea has its 
own advantage ; the first, in fact, while forming the celli 
eei'res as a support for the covering glass, and thna prft<' 
serves the Diatomaceffi from anj breakage ; it offers, hesideB, 
a aeriotia obstacle to the epreaditsg of the tnore liquid bitn- 
men of which the oater circle is oorapoaed ; and the li 
closes the cell by fixing the cover, which, when the prepara^ 
tion is drj, may be covered with a fioal circle of bitnmenl 
lb is of course understood that I am speaking of prepaid 
tiooa made in the drj way onlj, and Dot <vith halsam." 

One of the most fertile as well as the most curioua maga^ 
zioes of DiatoraaceiB is guano. The siliceona forma i 
taioed tfaerein have been devoared bj sea-birds a 
through the stomach aninjared, and after Ijiog for 
may be cleaned and classified. Many of these ere not e]se< 
where met with, so that the student who ia deairooa to entel 
into the study of DJatomaceio must be instructed as to the 
best mode of obtaining them from thia sonrce. The parr 
ticnlars to be observed ao closely resemble those before n 
tloned in the treatment of the ordinary diatoms, that it n 
be sofficiently explicit to give the ontlines of the procesK 
The guano must be first washed in pure water, allowed t"^^ 
subside perfectly, and the liq^uid then poured off. Thi 
must be repeated until the top Qaid is clear, and care takeii 
not to decant the Hqaid until perfect subsidence haa takeq 
plaoB. Tlie deposit must then be treated with hydrooblorii 
acid with a gentle beat for an hour or two, adding a little 
fresh acid at intervals as long as it excites any effervescencei 
After thia tjitrio acid must be aabatituted for the hydro- 
ohloiie, and the heat kept up to almost boiling-point fo( 
another hour at least, adding a little fresh acid as beforai 
When thia ceasca to act, the deposit mnat be allowed t 

OF Micaoscopic OBJECTS. "1 

settle perfectly and the acid poured off. All traces of the 
acid must now be washed away witii pure water, wian the 
remaias will be Diatomace;:e, the sand cod tain ed in the 
gnano, and a few other forma. Some of these may he 
moanted dry, as before meotioned, hat the greater portion 
ahonld he put up in Canada balsam aa described in 
Chapter rV. 

Such is the ordinary method for the treatment of guano ; 
but Mr, Ejlanda' mode of proceeding with ordinary Diato- 
macem (before given) nill be found equally suocessful with 
theae deposits. 

The compoaition, however, of guano is more complei than 
the Bobstances by which we Sod most of the Diatomaccie 
surrounded, and therefore a, different method of treatment 
is puraned by many. The following by Mr. A, J. Eoberta 
is B good one : " Guano should be first well washed with 
Ijoiling water, either on a paper filter or by repeated affu- 
BioDH until the liquid come off tasteless. Boiling water is 
preferable to cold, for the heat espels air-bubbles and causes 
the deposit to settle down into a smaller space; then the 
deposit mast be subjected to the action of the acids aa 
directed for the preparation of earths, to get rid of the lime 
salts. The partially cleaned deposit, which is now much 
smaller in bulk, must he separated as much as possible 
irom the liquid, strong sulpharia acid, in sufficient quantity 
to cover it, poured on to about the depth of half an inch, 
and heat applied and contioucd for sometime, but the liquid 
mast not be made to boi!. The result will be an almost im- 
mediate blackening of the liquid, which gradually becomes 
deeper, and a dirty, inky-looking compound is ultimately 
produced. When this has taken place, chlorate of potash 
in fine powder must be dropped into the hot misturo very 
graduaily until the black colour disappear. This must be 
dona cautiously, for the action is bo violent, that much 
spurting is occasioned ; and the liquid being very corrOBive, 
a tolerably capacious vessel should be uued in order to keep 
the splashes within reasonable bounds, or serious damage to 


tbe operator'a clothea laay ensile. Tbe nearly decoloi 
IJqaid must now be dilated witb a considerable qnaatitj a 
water, and tlie deposit allowed to subside, the enpernatanl; 
liquid ponred off, and the procesa of heating with snlpliDriafl 
acid and addition of chlorate of potash repeated until ihsfl 
Bulpburic acid occasion no further blackening; then tlittl 
cleaning may be finished in the usoal waj by waBhing." 

I have had many complaints from mj frieude that witltj 
all their care they have found nothing fit for moDuting ii 
gnano. This is readily acconnted for by one fact, that noi 
one sairple in twenty of what 18 called guano in tbe mark^ 
haa an atom of guano in it. Procure real guano, and JOitfl 
will get real returna. 

Tbe foBBil Infusoria (as they were formerly called) are Dowfl 
termed Diatomaceio, and are found in various parts of the J 
world ; such as Bermuda earth, Berg-roehl from Norway, tlio 
depoait from Monrne Mountain in Ireland, &c. They are 
found in imnenae quantities, and afford the microecopiat 
innumerable objecta. The same treatment as that UBoallj 
employed for tbe Diatomaceie must be followed nith t* 
deposita; but as they are sometimes obtaiopd in hard mai 
diaiatpgration is first necessary. To effect this, they a 
usually boiled for a sbort time in diluted Uqiuir j 
which will soon cause the maas to fall into a n 
deposit. Water muat then be iramedialely added, i 
that all further action of the liqaor potasea; may be stoppofljij 
otherwiae tbe objeota aearched for will be disaolTed. For tl ' 
reaaon it ia neoeaaary to understand what aubatauce is being J 
dealt witb, because aome depoaita are much finer and ara ■ 
acted upon more readily than others. 

In moanting these objeete, some are so delicate that t 
are almoat invisible when balsam is used with them ; t 
ore therefore nanally moonted dry. Othera, however, a 
much coarser, and rnay be nonnted in balaam like tbe D 
macesa mentioned in Chapter IV. 

The common Infuaoria cannot be mounted dry with, k 
great success, though a few may be placed upon the glai 

riiile and allowed to dry oatDrally, vihen ibeit cbaractera 
will be rery well ahomn. To obtain anytbing like a natural 
appearance, they mnat be put up in fluid aa iu Chapter V. 

Next to the DiatomaceEB, no class of microscopic objeota 
has been more looked into of late than the Forarainifera. 
These animala are almost all marine, having a jelly -lite body 
encloBed in one or more chambeTB of shell, which ia generally 
composed of carbonate of lime. The sbella are made with 
mintite orificea, throogh which the psendnpodia (falae feet) 
are extended by which the animal is enabled to lay hold of 
anything to draw itself along. From the possession of these 
orifices they derive their name, aa foramnt means a- door or 
opening. They have been found in every depth of aea 
hitherto eoaoded, each depth being abundant in certain 
ipecies; the lowest beds containing the greatest namber of 
fpeoimens, though with less variation of kinds. In chalk 
they are found in a fossil state, and may readily be shown 
(seo Chapter IV.) ; in limestone and other hard stones thoy 
are abandant, and some monDtaioH are composed principally 
of these shells. 

The methods of obtaining Foreminifera are various. Many 
may be found upon seaweeds, which should always be ex- 
amined as soon as possible after gathering. They are foand 
in maases upon some coaata where the wavea have carried 
and left them ; but they are to be found the most abundantly 
in sand or mud dredged from the bottom of the sea. They 
mnst, however, be cleaned and separated from the mass of 
impurity with which they are usually mistd. This may be 
done in various ways, according to the natnre of the accom- 
panying matter. If sand alone, as ia frequently the caae, 
the whole mass mnst be thorough!!/ dried, and then stirred 
np in clean water. The sand will soon eabside by ita ovn 
weight, but the chambers of the Foraminit'era, being filled 
with air, will flont upon the Burfaoe, and may be skimmed 
off. There u, however, one objection to this mode of pro- 
ceeding—some of those objects are so minute, the chambers 
containing comparatively so small a quantity of air, that 


they sink and are caat awaj with the refuse eand. On thi 
acooant it is preferable to take the trouble uf searchin 
certain soundings ncder the microicope, i 
hflir pencil, or some other contrivance before mentioned, 1 
extract tboBs objects which are required.* To clean tliBl 
Foramiaifera, FroresBor Williamson adviaes tbe transfer of^ 
the specimens to an evaporating dish containing a weak | 
solntioa of caustic potash. This must be boiled for f 
moDieats, nben the organic matter will be entirely dissolved, I 
and the calcareoas shells lefl free from imporitf. They J 
moHt con be well washed in water, so that all alkaline'^ 
matter may be entirely removed. 

If the specimens are in mud, we most proceed in a dif- I 
ferent way; — Stir up the whole maaa in water, and alloT f 
it to stand nntil the heavier portion has sunk to the bottom;' 
the water may then he ponred off and examined to e 
tbere are any objects contained in it. This process mnst ba 1 
repeated nntil the water come off qnite clear, when (if the m 
search is for ForamiDifera only] the solution of canstio^ 
potash may he used as before mentioned. However th 
soundings, &o., are cleaned. It is necessary to assort tiien 

* In Hearching any earth or sounding: in order to take objects tbero- 
from, DO methnd pre«:nt9 the Eame fndlitioa aa the uaa of Ihe GneHt 
camel-hair pencil, to whiah, after being drawn through tha lips, any 
forma will adhere, and yet be readily detached upon tbe slide. AFtOT 
Imailest objects may be separated. Captain Ijang, 

dip pi 

led ii 

power. With Bi rcrj fine hi 
about 1,1(10 Blidea, eaob 
h had from 

Ita adh^va 
iring one winter I mounteit 
t of sea soundinga, roany gf 
upon them. The rendineas 
lint and were detaohod. »' 

wibh which the objects adhered to the 
required, Teadcredtheproaeasmuch mc 
with gum. As to the numbers of objet 
ing, even imagination often faila. Plaiious, it is said, onlleoted 6,1 
shells of Foruminifera from ftn ounue of sand fiom the shore of L 
Adriatic. Soldani oollected from lesa than an ounce and a. hail 
roElc from the hills of the Ca^-eiana, in Tuseatiy, 10,46i tonal Bbi 
Several of these were ao minute that 500 weighed only a grain, j 
D'Orbigiiy found :!,81D,0D0 epeoimena in an ounce of sand from 
Bhures uf the Antilles. 


der the microBCope with the camel-hair pencil or other 
eontrivaiice, as it is impossihie to oLtaiu them fit for mount- 
iog without Dodergoiog thia proceBS. 

The Bea soandings taken by order of Govertitnent are 
drawn from the bottom in a Itind of apparataa ingeniooBlf 
made for the porpose, and the sand, mud, &c., are brought 
in their original state. Common Booodiugs, however, 

I taken hj loneriug a heavy piece of lead coated with 
tallow, which conseqaentlj brings np a small portion of the 
matter from the bottom, Mr. George Mosley, the late 
Secretary of the Manchester Microscopic Society, obtained 
numbers of the " scrapinga " from the soonding leada. To 
inalie any use of these it is, of oonrae, neceaaary to free them 
from all traces of the tallow. Mr. Dancer places the sound- 
ing in a basin aud pours boiling water opon it, which causes 
the melted grease to rise to the surface. When cold, thia 
may be removed, and the water carefully decanted. The 
operation may be repeated until no grease appears, when 
the water may bo withdrawn and liquor avimonim naed, 
which will form a soapy solution with any remaining grease. 
Thia must be treated with hot water for the final waahlag. 
Care most be taken leat the finer forms be carried away in 
decanting the washing liquid. Should it be wished to make 
certain as to this point, each washing should be examined 
under the microscope. In some cases the process of Mr, 
Dancer will prove sufficient. Mr. Dale, however, gives a 
method of acoomplishiog the same result, which is much 
more readily completed; and as no fault can be found with 
these results, I will here give it in foil ; It is now well known 
that one of the products obtained from the naphtha of coal- 
tar ia a volatile, oily substance, termed henzole (or, by 
Prench ohemista. benzine), the boiliog-point of which, when 
pure, is about 180° Fahrenheit, and which is a perfect 
solvent of fatty substances. In a capsule, previously 
warmed on a sand-bath, Mr. Dale mixes with the tallow 
Eonndinga aome of thia benzole, ontil diluted so as to rnn 
freely, pressing the lumpa with a glnas rod until thoroughly 


mingled ; the solation and its contents are tlien ponred ioti 
a paper filter, placed in a gla,ae funnel ; the capsule ia aga.iii 
washed with banzole, until the whole of the gritty particlei 
are retnoved into the filter. A watthing-hottle ia then sup- 
plied with benzole, and the eontenta of the filter washed to- 
the bottom nntil the liquid passes off pare, which maj bel 
tested hf placing a drop from the point of the funnel 
warm alip of glae» or bright pUtinum, when, if pure, thQ' 
benzole will evaporate without reaidae or tarnish ; if greawJ 
he present, the washing mnat be continned nntil thej ars, 
free from it. After riaaing through weak acid, or alcohol, 
for final purification, the calcareoQa forms will be read; for 

Tha filter audita contents maybe left to dry spontaneously, 
when the latter can be examined by the microscope. Should 
time be an object, rapid drying may be effected by any of 
the naual methods ; one of which, recommended by Mr, 
Dale, is to blow a stream of hot air through a glass tnbe 
held in the flame of a. Baasen'a burner, The loner the 
boiling-point of the benzole, the more readily can the 
gpecimena be freed from it. A commoner quality may ba 
nsed, bnt it ia more difficult to dry afterwards. 

Pare benzole being coatly, this may appear an expenaiTa 
process ; bnt, with the exception of a trifling loss by 
evaporation, the whole may be recovered by simpli 
tillation. Tho mixture of tallow and benzole being placed 
in a retort in a hot-water, a steam, or a sand bath, ths 
benzole will pass into the receiver, and the tallov or other 
impnritiea will remain in the retort. When the whole of 
the benzole baa distilled over, which is ascertained by its 
ceasicg to drop from the condenser, the heat iswithdrann. 
and the retort allowed to coot before the addition of freah. 
materia!. Half a dozen to a dozen filters, each with itt 
specimen, can be in process at the aame time ; and the dia-- 
tillation of the recovered benzole progreasea as quickly 
the filtration, which was practically proved on 
^ named. The process is very dangerous and great caution 

OF MiCROscoric OBJECTS. (7 

ia to be naed In the approaoii of light to the inflammaLle 

After the Foraminifera and calcareoaa formg have been 
removed, the residue may be treated viith acids and leviga- 
tion in the usual manner, to obtain siliceoas TormH aud 
discB, if there be any present ; bnt to facilitate their 
depoaitioB, and to avoid the loaa of any minute atoms 
Guspeniled in the washings, I would suggest the nee of 
filtiatioD. The conical filter is nusnitable, aa the particles 
would spread over too great a Borface of paper ; but glass 
tnbea open at both ends (such as broken teat-tubes) will be 
found to answer, the broad end covered with filtering -paper 
and over that a slip of muslin tied on with a thread to 
facilitate the paasage of the water and prevent the risk of 
breaking the paper. Snapend the tobe over a snitable 
vessel throngh a hole cut in thin wood or cardboard, pour 
in the washings, which can be thns filtered aud then dried. 
The cloth must be carefully removed, the paper cut ronnd 
the edges of the tube, and the diatoms on the paper disc 
may be removed by a camel-hair pencil or otherwise, ready 
for monnting. Thus many objects may be preserved which 
nonld he either washed away or only be obtained by a mori. 
tedions proceBS. 

Such is Mr. Dale's method of cleaning the aoundinga 
from tallow, and as it thoroughly accomplishes its end, and 
ia alike efFentive and not injurious to Foraminifera and dia- 
toms, it maybe safely reaommended. The weak solation of 
oattstic potaah before advised for Foraminifera, must not be 
naed where it is desired to preserve the diatoms, as they 
Tvoold certainly be injured, or destroyed altogether, if this 
agent were employed. 

In filing the Foraminifera upon the slide, no better plan 
can be followed than the dry cells and gum recommended 
in the early parts of this chapter. Owing to their thiotnesa 
and composition, moat of them are opaque objects only ; but 
they are eiqniailely beautiful, and require no particniar care, 
except in allowing the cell to be perfectly dry when 

L Cli& 


the oover is placed upon it, or tbe damp will certaiolj 
become condeaaoJ apan tbe inner side, and the examinatioii 
Berionaty hindered. 

Many of the ForamiDiferai require catting into sections if 
it ia wished to examine their internal atTnctnre ;— -" decal- 
cifying" ie alao desirable ia some cnaee : botb of thea 
procesaea will be roonil described at lengtb ia tbe chapter oa 
Sectiona and DisBecttona. 

When more than one apccimen of some particnlar a' 
obtained, it is better to place them npon the elide i 
fereot positiona, ao as to show aa much of the Btractore a. 
poaaibie. I will cooclade this subject by quotjag a 
I from T. Eymer Jones: "It is, therefore, by no meana Bn& 
I ficieut U) treat these ahells as ordinacj objects by sitnpljf 
laying them on a glaas alide, ao as to aee them only from 
one or two points of view ; thej mnat be carefully examined 
in every direction, for each ia the di»eraity of farm thi 
nothing short of this will be at all satisfactory. For th} 
purpose, they should be attached to the point of a ~ 
needle, ao that they may be turned in any direction, i 
eiamined by reflected light condensed npon them by □ 
of a Jena or side reflector. In many of the thick-shell 
speeiea it will be neceaeary to gi-ind them down o 
[aee Chapter VI.] before the number and arrangement s 
the internal chambers is discemible ; and in order 1 
inveatigate satisfactorily the miantiie of tbeir Btrnctara^ 
a variety of Sectiona, made in various wayi 
■ pen^able." 

A viaitor to the seasiJe may with little trouble procnra 
)ne of the most beautiful objects which can ornament B 
cabinet. On turning over atones which have been ft 
by the last tide, a very small species of starfish will often b 
met with. From a small circular centre f 
project, each of which ia covered with spines beautifully 
arraoged. When found, they should be dropped into fredl 
water with a little spirit added. This tillEs them instantly,, 
elaa many of tbeir long arms get broken by their struggles. 


B; poUang Oan into wster the arma sre rendend, toft and 
Mtsf tbas be ^nad in forms beat saiud to mitxroBOO{ilo 
■Hdcii, nod tliiu nSowcd to drj. They are be*alifuUx 
ddicat« in ooloar, needing no preparatioD to lil«a«h tlicni, 
Dviing tme mraning'a walk at Llaadudiio I pruciirod aboul 

Plants aSbid an almost ioeihanstiblo trcnsiiry for tho 
Hiicroscope, and maoj of tbem ehon their b«autii>s best wk^ii 
moanted drj. When aoj of these are to be uouDtad, e»n 
mnat be taken that they are tbornaglily dr?, otliervriin Ihd 
damp will certaiulj aii^e in the cell, aad iujiiru the objoctt 
and it may here be mentioned that long utter n luaf hiiM 
erery appearance of dryness, the interior ia hUII dikni[>, and 
no waj can bo recommeDded of getting rid of tliis by any 
qnicker process than that of keeping thou in a wnrnt room, 
aa many leaves, &c., are ntterly spoiled by using n hot irou 
or other contrivance. The safest way is to jirrsii ihcin 
gently betwist blotting-paper, which inny bt! rfniuTt-iI niid 
dried at abort intervals; and though this uiay tipiH'ur u 
tedioos operation, it is a so/s one. 

On the sarfacB of leaves, haira aod scales of vuriuiiB and 
very beantiful forms are found, most of which display their 
beauties beat when removed from the leaf, uiid usoj with 
the polarizer. These will be noticed in another plaoii-, but 
a portion of the leaf should always he prepared iti its nuturnl 
form, to show the arrangement of the hair or seules uj>on it i 
and this must almost invariably he mounted diy vrltvn UKi'd 
for this purpose. Many of them rer[oire very iJelii!Uto 
handling. The epidermis, or, as it is by some tornieil, tho 
cuticle, is the onter skin which lies upon the surfiine of tbu 
leaves and other parts of moat plaots. This ia compaaud of 
cella closely connected, often bearing the appnurunuo of a 
rude network. In many plants, by scraping up the surface 
of tbe leaf, a tbin coating is detached, which may be tatu 
off by takiag bold of it with forceps. The piece may thou 
be washed and Soated upon a glaas slide, where, on dry- 
ing, it will be firmly Eied, and may usually ho mounted 


drj. AmoDgat the most beaatifu) and ea,ei\j prepared ( 
these maj be meatioDed the petal of tlie geraaiam, ths 
cells of nhich are well de&aed and amoDgst the most 
in te resting. 

Sometirnea this ciitifle is removed b; maceration oE 
leaf in water or by a quicker method — boiling in nitric acid 
Perhaps it will be aa well to gi»B Mr. Arnold's experience 
"A leaf of a rhododendron which bad been drj sodh 
months, and a freBh I; -gathered leaf of an azalea, were put inbl 
a teat-tube, and covered with undiluted nitric acid of oon 
marce of, I believe, about 1'3'2 specific gravitj ; the tobe ml 
held over a, Bpirit-Iamp nntil the acid just boiled, a« 
the contents were then throtrn into a basin of cold watef 
The cuticle of tbo rhododendron leaf partially aeparatat 
spontaneonaly ; that of the azalea came off without thi 
least difficulty. The whole operation did not occupy mon 
than five minutes. Undoubtedly many leaves, according ti 
their texture, will require different strengths of acid, o-bA 
longer or shorter periods of boiling." 

Closely connected with the leaves are the anthebs an^ 
FOLLBN, of which a great uambor are beautiful and intereating 
sahjeota for the microscopiat. 

The mallaw tribe will faroish some exquisite objeet^f 
beariug the appearance of masses of costly jewels. The«a 
are usually dried witb pressure, but the natural form ma 
be more accarately preserved by allowing them to dry i 
they are taVeu from the flower, with no ioterferenoe except 
thoroughly protecting them from all dust. Sometimes the 
anther is divided, so that the cell required to receive them 
may be of as little depth as possible. The common mallow 
is a beautiful object, but I tbink the lavatcra is a better, as 
it shows the polleo-chambera well, when dried unpressed. 
The pollen is often sat alone, and is well worth the trouble, 
as it then admits of more close examination. Oftou it is 
convenient to have the anilier and pollen as seen io natore 
on one slide, and the poUtn alooe upon another. The 
former sboald be taken Jrom the fiovrers before their full 


deTelopment ia attained, aa, if overgrown, they lose ninch of 
their beanty. Some pollens are naturally ao dark that it is 
necesHary to moant them in Canada balsam or Said, as 
deBcribed in other plaoea; but they are better mounted dry 
when they are not too opaque. 

Here we may also mention the seeds of many plants as 
most interesting, and some of tbeni very beantifnl, objects, 
requiring for the greater part bot a low power to show them. 
Most of these are to be monnted dry, as opaque object?, in 
cells suited to them, but some are best seen in balsam, and 
will be mentioned in Chapter IT. 

The CoBALLiSES, many of which arc foond on almoafc every 
coast, afford some very valuable objects for the microscope. 
They mast be well washed when first prociired, to get rid of 
all the salts of the sea-water, dried and mounted in cells 
deep enough to protect them from all danger of pressure, 
e of them are exceedingly fragile. The white ivory 
appearance which some of them present is given to them by 
1 covering of carbonate of lime ; and shoiild it be 
desired to examine the structure of these more closely, it 
may be accomplished by keeping them for some time in 
vinegar or dilute muriatic acid, which will remove the lime 
and allow of the substance being sliced in the same way aa 
oOier Algfe. {" Miorographic Dictionary," p. 183.) 

Tkb Scales op Insects. — The fine dust upon the wings 
)f moths and butterflies, which is so readily removed when 
they are bandied carelessly, is what is called the scales. To 
these the wing owes the magnificent colours which so often 
are seen npon it ; every particle being what may be termed a 
distinct £at feather. Row these are placed (somewhat like 
tiles upon a roof) may be easily eeen in the wing of any 
butterfly, a few being removed to aid the investigation, 
" Their form is naually that of the battledore with which 
the common game is played, but the handle or base of the 
scale ia often short, and the broad part varits in propor- 
tionate length and breadth in different specimens. The 
markings upon these also vary, some being mostly composed 


of lines rnnning from the base to the apex, others reminding 
ns of network — bead-like spots only are seen in some — 
indeed, almost endless changes are fonnd amongst them. 
These scales are not confined to batterflies and moths, nor 
indeed to the icings of insects. The different gnats sapplj 
some most beautiful specimens, not onl^ from the wings, 
bat also from the proboscis, &c. ; whilst from still more 
minate insects, as the podura, scales are taken which are 
esteemed as a most delicate test. The gorgeoas colours 
which the diamond beetles show when under the microscope 
are produced by light reflected from minute scales with 
which the insects are covered. 

In mounting these objects for the microscope it is well to 
have the part of the insect from which the scales are nsaallj 
taken as a separate slide, so that the natural arrangement 
of them may be seen. This is easily accomplished with the 
wings of butterflies, gnats, &o. ; as they require no extra- 
ordinary care. In mounting the scales they may be placed 
upon slides, by passing the wings over the surface, or by 
gently scraping the wing upon the slide, when they mnst be 
covered with the thin glass. Of course, the extreme tenuity 
of these objects does away with the necessity of any cell 
excepting that formed by the gold-size or other cement nsed 
to attach the cover. The scales of the podura should be 
placed upon the slide in a somewhat different manner. This 
insect is without wings, and is no longer than the common 
flea. It is often found amongst the sawdust in wine-cellars, 
continually leaping about by the aid of its tail, which is 
bent underneath its body. Dr. Carpenter says : — " PodursB 
may be obtained by sprinkling a little oatmeal on a piece 
of black p^er near their haunts ; and after leaving it there 
for a few hours, removing it carefully to a large glazed basin, 
so that, when they leap from the paper (as they will when 
brought to the light), they may fall into the basin, and may 
thus separate themselves from the meal. The best way of 
obtaining their scales, is to confine several of them together 
beneath a wine-glass inverted upon a piece of fine smooth 

or jocBOTCOPic QftrecTS. 83 

paper ; for the scales will become delated hj Uieir leipB 

against the glaaB, aad wiQ Ml gpon Uia p^to-." Thno 
seales are removed to the elide, and moaoted ta those frcna 
goats, &c. When the podara has been caoght withoat the 
aid of meal, tt maj be placed upon the shde, under a test- 
tnbe, or by anj other mode of confiDemeut, and thus save 
the tronbla of transfer from the paper before meolioned. 
Another method is to seize the insect bj the leg with the 
forceps and drag it across the slide, when a Eufficient qnan- 
tit; of scalea will probably be left npon it. 

Mr. Mclntyre procnrea the scales in the foUowing man- 
ner : — He makes what he l*rms a breeding-e^e, by taking 
a piece of plate-glass four inches long by two iochei wide, 
and over this places a few sheets of blotting-paper. Upon 
these he lays a aheet of cork about a quarter of an inch 
thick, with a circle cot out of the centra one inch wide. 
This gives a kind of box, which he covers with gla^s, kept 
firm by two elastic bandB. He says ; — " After capturing 
the insect by means of a tnbe and a camel-hair pencil, I let 
it remain for some days in one of the breeding-cages, into 
which I always transfer the newly -cnnght podura, until it 
has changed its skin ; then I stupefy it with chloroform, 
and drop it out on to a thin glass cover (previously cleaned) 
and with a very clean needle-point roll it backwards and 
forwards npon the cover till enfficieut scales are removed. 
A very light pressore is indispensable, so as not to sqaeeze 
out any of the insect's fluids." 

These scales are usually mounted dry ; but Hogg re- 
commends the use of Canada balsam (Chapter IV.) as ren- 
dering their structure more definite when illuminated with 
Wenham's parabolic reflector. Some advise other methods, 
which will be mentioned in Chapter T. As most insedg 
when undissected are mounted in Canada balsam, the dif- 
ferent moiies of treatment which they require will be stated 
in another place. 

In mounting blood of any kind to show the corpuaeles, 
or, as they are often called, glahvXee, which are round or 

81 PIlEPillAIlOK iSD 

oval discs, it is but necessary to cover the alide on tlie spot 
required with a coatiog as thin as possible and ailon it to 
dry before covering nith tliin glass. There is a slight con- 
traction in the globules v>heii dried, but not enough to in- 
jure them for the mioroacope. The shape of these varies in 
different cIbsbcb of auimalB, bat the size varies much more, 
some being mainy times larger than others. Perhaps it nil! 
not be out of place to say a few words concerning the detec- 
tion of blood. Wherever the stains are, they must be care- 
fully scraped avay and immersed for a few bonrs in a wesik 
Bolutioa of bichloride of mercury. With a thin tuba tie 
more solid portion may tlien be removed toa glass slide and 
examined with a somewhat high power. A slight knowledge 
of the microscopic appearance of blood-discs will show m 
whether the suspicion of blood is correct. 

Some of the skins of lamtB are beantifol objects ; bot, Uka 
many sections of animal and other fragile matter, are diffl- 
cult to extend upon the elide. This difficulty is easily OTei>' 
come by floating the thin object in dear water, immersing, 
the slide, and when the object is evenly spread gently lifting- 
it. Allow it then to dry by slightly raising one end oi 
the slide to aid the drainage, and cover with thin 
other objects. The tails and fins of many small fiah ma,f 

a similar i 

A few objects which ai 
may be here mentioned e 

)ogh some of them '1 

1 well worth Iht' 

re best shown by mounting drf' 
a a slight guide to the beginner 
e been before noticed. Many of. 
the Foraminifera, as elsewhere described. Some cnjsialg are 
Bolnble in almoet any UuJd or balsam, and should be monnted 
diij; a few, however, deliquesce or effloresce, which renderf 
them worthless as microscopic objects. 

The wings of botterflies, gnats, and moths will affoni 
many specimens wherewith to supply the cabinet of ti^ 
young stodent. A great variety of scales also may be ft 
amongst the ferns \ indeed, these aloue will afford 1 
student occupation for a long time. On the nndei 

p Kicuoscopic c 


the leaTBB are the reservoirs for the aparea, which in maoy 
inBtancea aomewhat reaemble green velvet, and are arranged 
in atripeB, round maases, and other forms. The aporea are 
QSQEill; covered with a thin akin, nhich ia oariouBlj marked 
in some specimens, often very like pollen-graina. The man- 
ner in which these spores with all their accompaDiments 
are arranged, their changes and developments, afford almoBt 
endleaa anbjects for atudj; different ferns presenting uh with 
maoj variationa in this reapeot totally inviaiblo withont the 
aid of the microscope. The hymenophylloma (of which two 
only belong to England) are particularly interesting, and 
the alroctare of the leaves when dried makea them beantifnl 
objects, often requiring no balaam to aid thoir transparency. 
Portions of the fronds of ferna should be mounted aa opaque 
objects, after having been dried between blotting-paper, 
when they are not injured by pressure ; bat care must be 
tahen to gather them at the right time, aa thej do not show 
their beaotj before they are ripe, and if over-ripe the ar- 
THugemeut of the apores, &•:., ia altered. The aporea may 
be mounted aa separate objecta in the aame manner as 
pollen, before mentioned, and are exquisitely beautiful when 
viewed with a tolerahly high power. The number of foreign 
ferns now cnltivatcd in this country baa greatly widened 
the field for reaearch in this direction ; and it may also be 
mentioned that the under-sides of many are found to be 
covered with scales of very beantifnl forme. A small 
piece of the frond of one of these may be mounted in its 
natural state, but the removal of the scales for eiamina- 
tiou by polarized light will be deacribed in another place. 
The moaaea alao are quite a little world, requiring but a low 
power to show their beantiea. The leaves are of varioua 
forma, aome of which reaemble beautiful net-work ; the 
" urns" or reaervoira for the spores, however, are perhaps 
the most interesting parts of these objects, aa alao of the 
liverworts which are closely allied to the moasea. These 
nrna are generally covered by lida, which fall off when 
the fruit is ripe. At this period they are well fitted for the 


microscope. The common Bcrew-moss may be foond in 
great abuudance, and sbows this denudation of the Hporea 
very perfectly. Many of these may be easily dried without 
roncli injury, but they shoald also be examined in thnc 
natural state. 

The Btudent should nob omit from his cabinet a loaf d 
the nettle and tlie allied foreign Bpecies, the mystery 
which the microscope will make plain. The bairs or uting 
may also bo removed, and viewed nitb a higher power thai 
when on the leaf, being so transparent as to require a 
sam or other preservative. 

There are few more interesting objects than the raphido 
or plant-crystale. These are far from being i 
Bome plants they are very minute, and oonsoqoeiitly reqnin 
care in tbe mounting, as well as a high magnifying powa 
to render them viaible; in others they are so largo that 
about twenty-five of them placed point to point would reach 
one inch. Some of these crystals are long and compara- 
tively very thin, which suggested the name (raphie, a 
needle); others are etar-lil<:e, with long and slender rays] 
while others again are of a somewhat similar form, e 
being solid and short. If tho stem of rhubarb, or 
any of the hyacinth tribe, be bruised, so that the jni 
flow upon tho slide, in all probability same of these cryo' 
tals will be found in the fluid. To obtain them olean, 
they must be freed from all vegetable matter by maceration^ 
After this they must be thoroughly washed and moant«d 
dry. They are also good polarizing objects, giving bril- 
liant colours; but when used for this purpose they muit 
be mounted as described in Chapter IV. A few plantii 
which contaia thetn may be mentioned here. The Cao-i 
taeeiB are very proliBc ; the orchids, geraniams, tulips, aai 
the outer coating of the onion, furnish tho more unnsnat 

The Fungi are generally looked upon as a very difficult 
elaas of objects to deal with, but amongst them some oL 
the most available may be fonnd. The forms of many ara 

OP MicEoacopic OBJECTS. 87 

very beantiful, bnt are so minute as to require a liigh mag- 
nifying power to show them. The mould which forms on 
man; HubBtaoces is a fungua, and in some cases may he 
dried and preserved ia ita nataml state. A friend of mine 
broaght rae a roae-bush completely covered with a white 
Wight. This was found to be a fnogus, whioh required a 
high magnifying power to show it. Being a very interesting 
object, it was desirable to preserve it, and this was perfectly 
effected without injury to the form by simply drying the 
leaf in a room nsnally occupied. Amongst the fungi are 
many objects well worth looking for, one of which is the 
Diack^EO, elegnnB. This, tlie only Bpeoies, says the Micro- 
grapbia Dictionary, ia found in England upon the living 
leaves of the lily-of-tlie -valley, &c. Theae little plants grow 
ia moases, reminding one of mould, to a height of a quarter 
of an inch, and each " stem " is covered with a aheatb, in 
shape somewhat like an elongated thimble. When ripe the 
sheath falla oS aod reveals the same shaped column, made 
up of beautifully fine networi, with the spores lying hero and 
there. This dries well, and ia a good object for the middle 
powers. Amongst tbe fnngi the blights of wheat and of 
other articles of food may be included. Many of them may 
be mounted dry; othCTS, however, cannot be well pre- 
served except in liquids, and will be referred to in Chap- 
ter V. When rambling in a wood during the sammer I sat 
down upon the fallen trunk of a tree, and here and there a 
few minute white spots caught my eye. I toot my Cod- 
dingtoD Ions from my side-pocket and applied it to these. 
Judge of my surprise when I fnund each white speck a 
diatinotly formed fnngos resembling in Biie and form, to an 
amusing similarity, a disc of the atachnoidiaous. They were 
already dry, and I monnted them aa ordinary dry objects ; 
and hitherto no change has taken place which I can detect. 
Amongst the Eoophytes and eea-mats, commonly called 
sea-weeda, may be found very many iuteresting objects to 
be monnted dry. WUen this mode of preservation is used, 
it ia necessary that all the sea-aalt be thoroughly waahed 

S3 rKEPARiTion axd mountikg 

from them. As tbej are, however, moat frequently rooonted 1 
in balaam or liquid, tbej will he mora fully noticed in other f 

The scales of fishes are generally mountad dry when 
nsed as ordinary objects; but for polarized light, balsam o 
liquid must be need, bb noticed in Chapter IV. To nionnt 
a fish-scale, however, in q satiafactory manner, cara roust be 
taken that it ia perfectly clean. Tbia can be accompliahed 
only by careful washing, in which proceas soft cnmel-hair 
pencils will often be useful. When the Blime or mucas haa 
once dried, it ia very difficult to remove. Tbe variety and , 
beauty of these are quite surprising to the novice, 
also very interesting to procure tbe sbin of tbe fish ^ 
poaeible, and mount it on a separate slide to ahow hon 
scales are arranged. The sole ia oue of the most unasnal | 
forma, the projecting end of each scale being covered witk I 
spiuen, wbicli radiate from a common centre, while those at 1 
tbe eitremity are carried out aomewbat TOaembling the raya I 
of a star. One of the akatee has a spine projecting from tba 1 
centre of each scale, wliich ia a very curious opaque object, I 
eapecially when the skin ia mounted in tbe manner deBcribed. 
The perch, roach, minnow, and others of the common fishes i 
give the student good objects for-his cabinet, and may be < 
procured without difficulty, Tbe scale of tbe turbot is a 
splendid object for the pol aria cope when mounted in balsam. 

Insects wbich are very transparent, or have tbe " metallio 
lustre" with wbich any medium would interfere, a 
dry. The diamond -beetle, before mentioned, is a splendid J 
example of this ; tbe back is generally used, but the legs, , 
showing the curious feet, are very interesting o' ' 
deed, amongat the legs and feet of insects there ia a wide- f 
field of interest. When they are of a horny nature, it ie 
heat to dry them in any form preferred, but to use nt 
pressure; when, however, they are wanted fiat, so as it 
show the feet, &c., eitended, they must be dried with a J 
gentle pressure betwixt blotting-paper if possible. But this J 
will be treated more fully in Chapter IV. 

ehonld i 

of crabs. You c 
deceived when yi 

e aicKoscopic objects. 89 

syrm ofiiucctg are Hometimes allowed to dry in their 
natural shape, and mounted as opaqne ohjecte ; but generallj 
they are naed aa tran spares c lea in balsam or liquid, ho the 
description of the treatment which they require will be 
deferred to Chapter IV. 

Hairs, when not too dark, are sometimes transparent 
enough when monnted dry, hot are usoally moanted in 
baleam. These will be more fully noticed in another place, 
but there are some without which no cabinet ia deemed in 
anynise complete. Many different species of bats, English 
and foreiftn, present us with hairs the form of which we 
dared to imagine without microscopic 
s objects are found in the anteunm 
also readily know whether you are beiug 
bny what you deem a. real sealskin or 
sable, from some of the common caterpillars I have ob- 
tained exquisitely beautiful slides, and a kangaroo is a true 
friend to an object -gatherer. 

The hair of the ornithorhynohns is a very cnrions object, 
baving- a thin place in the middle of its length, and so pre- 
senting somewhat the appearance of a flail. 

These are a few of the objects which are often monnted 
dry, but some of them sbonld he shown in balsam or liquid 
also, and there is much difference of opinion as to the best 
way of preserving others. This, however, is eiplained by 
the fact, that the transparency which balsam gives, inter- 
feres with one property of the object, and yet develops 
another which wonld have remained invisible if preserved 
dry. The only method of overcoming this difficulty is to 
keep the object mounted in botli ways, which is comparatively 
little trouble. 

I may here mention that many prefer the lieberkuhn 
for the illumination of opaque objects; and a good back- 
ground is gained by putting opon the undor-side of the 
elide, immediately beneath the object, a spot of black varnish, 
which does not interfere materially with the light, 




The natare and use of this substance lias been before spoken 
of, so that the method of working with it may be at once 

Perfect dryness of the objects is, if possible, more neces- 
sary in this mode of mounting than any other, as dampness 
remaining in the object will assuredly cause a cloudiness to 
make its appearance in a short time after it is fixed. Where 
pressure does not injure the specimens, they are most suc^ 
cessfuUy treated when first dried betwixt the leaves of a 
book, or in any other way which may prove most convenient, 
as noticed in Chapter III. 

Before describing the methods of proceeding with par- 
ticular objects, general rules may be given which should be 
observed in order to succeed in this branch of mounting. 

As the object is to be thoroughly immersed in the balsam, 
it is evident that when it has once been covered, so it must 
remain, unless we again free it by a process hereafter men- 
tioned, which is very troublesome ; and on this account there 
must be nothing whatever in the balsam except the object. 
The inexperienced may think this an unnecessary caution; 
but the greatest difficulty he will meet with is to get rid of 
minute bubbles of air, perhaps invisible to the naked eye, 
which appear like small globules when under the microscope, 
and render the slide unsightly, or even worthless. Balsam 
dissolved in benzole will be found invaluable in mounting 
without air-bubbles ; if a few are left in the specimen, by 
the next morning they will have entirely disappeared. In 
making this solution the balsam should be first boiled 
gently till on dropping a small quantity into water it is 


ibimd to he aa hard aa tesio, the Boftened and warm Eolution 
may be now poured into a bottle, and when cool the benzolo 
added in sufficient qnantity to make it of a desirable thick' 
nesB. Ten objects oat of eleven contain air, or at least aio 
fall of minute holes which are necessarily tilled with it ; so 
that if they shonld be immersed in any liquid of thick 
consiatency, these cella of air wonld be imprisoued, and 
become huhhles. The air, then, must be remored, and this 
IB nsaally accomplished by fioabing for ioma time iu tarpen- 
yne, the period required differing according to the nature of 

9 object. In some cases, the turpentine acta upon tho 
colour, or even removes it altogether, so that it must be 
watched carefally. Often, bonever, this ia an advantage, 
as where the structure alone ia wanted, the removal of the 
colouring matter rendera it more transparent. There arc 
objeetB, however, which retain the air with snch tenacity 
that Boaking alone will not remove it. If these will bear 
beat without being injured, they may be boiled in turpentine, 
' I balaam, when the air will be partly or totally 
erpelled. Uut where heat is objectionable, they muat be 
immersed in the turpentine, and so submitted to the action 
of the air-pump. Even with this aid, sometimes daja are 
required to accomplish it perfectly, during whieh time the 
air should be eihanated at intervals of five or aii hours, if 
convenient, and the objecta turned over now and then. 

Many complainta are made concerning turpentine, both 
u to ita cleanliness and penetrating power. Most of these 
spring from the fact that few substances in the market vary 
a mnch as turpentine in purity ; all aorta of rubbish are 
Bold nnder this name, and now benzole is employed by many 
'n alt cases where turpentine aloae was once used. 

Sometimes the objects are so minute that it is impossible 
to anbmit them to any soaking, and in this case they must 
be laid upon the slide at once, and the turpentine applied 
to them there. But it mnst not be forgotten that there are 
- Borne few which are much better mounted in such a way 
that the balsam may thoroughly surround, and yet not 




The natare and use of this substance has been before 6pok< 
ofy 80 that the method of working with it may be at on 

Perfect dryness of the objects is, if possible, more nec< 
sary in this mode of mounting than any other, as dampn> 
remaining in the object will assuredly cause a cloudiness 
make its appearance in a short time after it is fixed. Wl. 
pressure does not injure the specimens, they are most !^ 
cessfuUy treated when first dried betwixt the leaves o 
book, or in any other way which may prove most oonvenit 
as noticed in Chapter III. 

Before describing the methods of proceeding with - 
ticular objects, general rules may be given which shoul 
observed in order to succeed in this branch of mountin*^ 

As the object is to be thoroughly immersed in the bal 
it is evident that when it has once been covered, so it i 
remain, unless we again free it by a process hereafter . 
tioned, which is very troublesome ; and on this acoouut 
must be nothing whatever in the balsam except the i' 
The inexperienced may think this an unnecessary cai 
but the greatest difficulty he will meet with is to get . 
minute bubbles of air, perhaps invisible to the nake«' 
which appear like small globules when under the micro 
and render the slide unsightly, or even worthless. E 
dissolved in benzole will be found invaluable in mo: 
without air-bubbles ; if a few are left in the specim' 
the next morning they will have entirely disappear^- 
making this solution the balsam should be first 
gently till on dropping a small quantity into wati 

V2 nT7\-tlTIfly JJD X0U5TU6 

ffTMiivzti:, the tribetaisce more tliazi neeeasaxj. Sections of 
tttth aT'^ &=ioagn these, bat thej will be notioed in another 
place, ani some insects Caee Dr. Carpenter) when required 
to ehow the ramincations of the tracheae. 

Having freed the object, then, from these two enemies^ 
dampness and air — we now proceed to monnt it. 

The slide mnst first be cleaned; then on the centre a 
quantity of balsam most be placed with a blontlj-pointed 
glass rod, according to the size of the object about to be 
mounted. To this a slight heat must be applied, which 
will cause anj bubbles to rise from the surfiioe of the slide, 
so that they may be readily removed with a needle. The 
object having been freed from all air by steeping in turpen- 
tine, as before described, and then from superfluous liquid 
by a short drainage, or touch upon blotting-paper, is to be 
carefully laid upon, or where it is practicable thrust tnto, 
the balsam just prepared on the slide. In the former 
case, or where the balsam has not totally coyered the object, 
a small quantity must be taken, warmed, and dropped upon 
it, and any bubbles removed by the needle as before. To 
cover this, the thin glass must be warmed, and beginning 
at one side, allowed to fall upon the balsam, driving a 
small *' wave " before it, and thus expelling any babbles 
which may remain. This is quite as safely performed (if 
not more so) by making a solution of balsam in turpentine 
of the consistency of thick varnish or by the use of chloroform 
and balsam, as mentioned in Chapter II. The thin glass oover 
may bo slightly coated with this, and will then be much 
loss liablo to imprison any air, which frequently happens 
when the cover is dry. Babbles, however, will sometimes 
make tlioir appearance in spite of all care ; but when the 
object is comparatively strong, they may be removed by 
keeping the slide rather warm, and working the cover, a 
little, HO as to press them to one side, when they should be 
iui mediately removed with a needle point, otherwise they 
arc a^niu drawn under. 

Wlicro the slide requires keeping warm for any length of 

or MiCKOscoPic OBJECTS. 93 

time, a. }ioi-toater hath ia sometimes mado nae of, wliich is 
Guaplj B. flat tin, or other metal case, with a, moath at the 
ude, that when the hot water is iatrodnced it may he closed 
op, and BO retain its warmth for a long time. An escellent 
bath may he made of an oriJinary water-plate — coating 
al)ont 1b. 9d. Thia may bo filled either with hot water or 
Band, and if to it be added a flat tta cover such ae ia naed 
in eating-houses, costing about 6i. — a Tery effective OTen. 
for baking alidea ia the result. It may he placed on the 
hob, or over or near any eonroe of heat. It is easy to add 
a thermometer if necessary. In working, tho sHde ia laid 
upon it, and so admits of longer operations, when rec[uired, 
withont growing cold. Sometimes a spirit-lamp is placed 
under it to keep up an equal heat through escessively long 
processes. Where the time required, however, is bnt abort, 
a thick brasa plate is sometimes used (see Chapter II.), 
which may be heated to any degree that is required, the aEde 
being previously placed upon it. 

Some objects, which are bo thin that they are uanally 
Hoated upon the slide, as before stated, require no steeping 
in tarpentine or other liquid. These are best mounted by 
covering with a little dihiiM halaam, and after this has had 
time to penetrate the anbatance, ordinary balsam is laid 
npon it, and the slide finished in the usual manner. 

I have stated that balsam is usually applied to the slide 
and objecte with a blontly -pointed glass rod ; but for the 
pnrpoae of drawing the halaam from the bottle, and convey- 
ing it to the desired place. Dr. Carpenter nses a glass 
syringe with a free opening. These are his instructions : — 
"This (the syringe) is most readily filled with balaam, in 
the firat instance, by drawing out the piston, and pouring 
in balsam previously rendered more liquid by gentle warmth; 
and nothing else is required to enable the operator at any 
time to eipel precisely the amount of balsam be may require, 
than to warm the point of the syringe, if the balsam should 
have hardened in it, and to apply a very gentle heat to the 
syringe generally, if the piston should not then be readily 


pressed down. When a number of balHam objects are being 
moDDted at one time, the advantage of this plan in regarct^ 
to facility and cleanliness (no anperdnoas balsam being' 
cleposited on the slide) will make itself aensiblj felt," bat 
the collapsible metal capsules are certainlj tbe best and 
most easily managed. 

When the mounting has been thns for accomplished, 
the outer wall of balsam may be roughly removed after a 
few hours have elapsed; but great care is necessary lest ^^ 
the covet be moved or disturbed in any way. In this ^^ 
state it may be left for the final cleansing nntil the balaam ^^r^a 
becomes hard, which tales place aoouer or later, acoordiug "^^^g 

td the degree of warmth to which it has been sabjected ^3. 

Many advocate baking in a slow oven to accelerate thi^^ -ia 
drying; bnt with some objects even this heat woold b^» oe 
too great, and generally a mantel-piece, or other plac^^f^ce 
about eqnal to it in temperature, is the best suited* ^d 
to this purpose ; and when the rcqaisite hardness ii -i: is 
attained, the slide may be finished as follows : — With s a 

pointed knife the balsam mast be scraped away, taking car -r^c-re 
that the thin glass be not cracked by the point getting ^trag 
iinder it. If used carefully, the knife will render the slid^Earie 
almost clean ; bnt any miunte portions which still adherri^Er are 
to the glass must be rubbed with linen dipped in tnrpentiw — ^m e 
or spirit. If the balsam is not very hard, these smtL^ ^H 
fragments are readily removed by folding a piece of pap^ -^er 
tightly in a triangular form with many folds, and dampil^^^^HD^ I 
the point with which the glass is rubbed. As the pap 
becomes worn with the friction, the balsam will be carri»- 
off with it. In some cases I have found this simple e= 
pediont very nseful. 

Sometimes the object to be mounted is of such a thic: 
neas as to require a cell. For this purpose glass rings e 
used (as described in Chapter V.), and filled with bals^ 
The best mode of doing this is thus described by Mr. T- S 
Kalph in the Microscopic Joiinial: — "The question vwaa 
asked me when I was in England, if I hnevi how to EU a 

ECTS. S!) 

a lamp of fresli cbalk into pieces not larger than a walnut ; 
then) crneh, but not grind, leat jou dtstroy the forma, into 
& coarse powi^er that will pass a somewhat wide sieve. Tie 
thia, as a pudding, in a, stout piece of calico. Drop into 
nater and allow the bundle to become aatorated, and tlien 
tnead with the hande. Thia will espel a quantity of milky 
water. From time to time, after allowing the fluid to drain 
off, the cloth should be untied, acd retied more closely to 
the masB ; and when the contents are reduced to about one- 
third of their originsl bulk, all large pieces of chalk, portious 
of spinea of echini, &c., should be removed, lest tliey injure 
the more delicate forma. Care mnat be taken in the 
kneading when the greater portion of the chalk has 
eacaped, and at last the bag only shaken until the water 
fiowB from it almost clear. Tbs whole may then be trans- 
ferred to a bottle ot clear water and treatL'd aa before 
described. The reaulta, Mr. Bobertson saya, will be aatia- 
fikctory, and the chalk must be Tery poor in foasils if 2 lb. 
would not aatisfy any microacopic obaerver. 

"When the Poraminifera are of a larger aize.thongh trana- 
parent enongh to be monnted in balsam, the air must bo 
first expelled from the interior, otherwise the objects will be 
altogether unsatisfactory. To accomplish this they must 
be immersed in turpentine and submitted to the action of 
the air-pump. So difficult is it to get rid of this enemy, 
that it is often necessary to employ three or four exhans- 
tions, leaving Ihem for some time nnder each. When all 
air haa given place to the turpentine, they nmst be mounted 
in tbe ordinary way. 

Of all objects which are commonly met with, few are such 
general favourites as the Poltctbtin.e ; and deservedly so. 
Their forms are most beantirul, and often peculiar — stars 
' varying in design, others closely resembling crowns ; the 
a Arielotdls like a croaa, and many whose shapes 
1 words could deaeribe. The greater part, perhaps, of 
1 those whicb are usoally sold, are from tbe rocky parts of 
t Bermuda; but they are aleo found in Sicily, some parts of 


Afrits and America. Tfacr are DSamllj- moanted in ba]8«m. 
bnt are eqaallj beaatiful moanted drj, and Deed with tha 
IreberLnfao. Tbej require as mach care ia cleaning &■ the 
CiatoiDacese. but tbe process is a different one, Sametinie* 
tbia ia effected by simplj washing nntil thej are freed trom 
nil ettraneouB matter ; bat this ia seldom as efiectnal as it 
shoaid be. In the Mirratet^ie journal Mr. Farlong givea 
tbe following method of treatment as tbe best be knowB : — 

A large glass Teasel with 3 or 4 qaarta of water. 

XeiT tin saucepan holding 1 pint. 

2 thio precipitating glasses holding 10 at. eaoh. 
Take 3 or., of drj Barbadoes earth (lumps are best), and 
brealc into rather Hmall fragments. Put 3 or 4 at. of uom. 
lunn washing soda into the tin and half Gil it with water. 
Boil strongljr, and having thrown in the earlh, boil it for 
half an hour. Poor nine-tenths of this into the large glass 
vessel, and gentlj crush the remaining lumps with a soft 
brialle brash. Add aoda and water as before, and boil agaia ; 
then pour o£r the liqnid ioto tbe large vessel, and repeat 
until nothing of value remains, Stir tlie large vessel « ' 
an ivory spatula, let it stand for three minutes, and pour 
gently off nine-tenths of the conteata, when the sheila will be 
left, partially freed only, like sand. 

2kd FjtocEsa, — Fat common washing foda and water into 
the tin as before, and having placed the sheila therein, boil 
for an hour. Transfer to tbe large vessel as before, and 
after allowiog it to stand for one minute, pour off. Each 
washing brings off a kind of '' Hock," nUiub seema to be 

3iin Fkocess.— Pot the shells in a precipitating glass 
drain off the water nntil not more than ^ oz. remains. Add 
half a l^eaapoonful of bicarbonate of soda, dissolve, and then 
pour in gently 1 oz.of strong sulpfanria acid. This liberate! 
the " flock," etc., and leaves the shells beautifully trans- 
parent. Wash well now with water to get rid of all soltl 
and other aolable matter. 


Some of tbe large ebella are destrojed bj tbia method, 
bat none tbat are lit for microacopic uBe. An obliqne light 
ebowH theBe 0>ji;cts best. 

Tbeae are Bomctimea treated in the manner described in 
Chapter III., where the diutome are apoken of, but inaTij 
foriDH are Hable to be injured by Ibis severe proceeB. 

It baa been before stated that some of tbe znophjtea may 
be mOQoted drj, and others eiamioed bs opaque or trana- 
parent objrcta accordini; to their anbataDce. They are very 
intereatidg when examined in the trongh whilst living, but 
to pteaerte many of them for future eiaminiition they must 
be mounted in aome preservative medium. Sooietimea thia 
may be one of the liquids mentioned in Cliupter Y., but 
if possible they sbonld be kept in balsam, as there is leas 
danger of iojnry by accident to tbia kind of elide. This 
method of mounling presents some difficnlties, but I think 
that all agree as to the trnstworthtneas of Dr. Golding 
Bird's information on tbe subject, which appeared in tbe 
MicToecopie JuunwX. Of this, apace forbids me to give more 
than a wmdeneed account, but I hope to omit nothing of 
moment to the reader for whom these puj^es are written. 

AfUr atating that there are few who are not familiar 
with theae exquisite forms, and have nut regretted tbe great 
losB of beanty they eostain in drying, he informs ns that 
from their ho obstinately retaining air in tbe cells and tubes 
when dried, it is hardly practicable to get rid of it ; and they 
ftleo shrivel up very seTiooHly in the procees of drying The 
following plan, however, he has found almost jaulilesa in 
their preparation. 

To preserve them with eitended tentacles, they ahoiild 
be plunged in cold fresh water, winch kdls them ao quukly 
that these are not often retracted.* The epecimena ehould 
be preserved in spirit until there is leisure to prepare tbirm , 

• It b»i been stotert thHt the Ijeaf roBthod of killinff Koo|.hjte6 ia t« 
drop Bluohol, French bramij, or benao!e into ibe baIi vMrr iu which 
they are plHsed ; as ibia will uHuaa do retniutiou uE tentulus if ic be 
dang gradually. 


if, however, they have been dried, they should be soaVed ii 
cold water for a day or two before being Bubmitted to the 
following proccaaee: — 

1. After selecting perfect Bpeoimeos of snitsble aizi 
roerse them in water heatifd to aboat 120°, nnd place them 
under the reoeiver of an air-pnmp. Slowly exhaust the 
air, when bubbles will rise and the water appear to be ' 
state of HCtire ebullition. AfXer a few miautea re-adnit thi 
air and again exhaust, repeating the process three or four 
tiroea. This will displace the air from most, if not all, of 
the class. 

2. Bemove the specimens and allow tbem to drain npon 
blottiDg-paper for a few Beconds ; then place them in an 
earthen vessel fitted with a cover, and preTJouEl; heated to 
about 200°. This heat may be easily got by placing the 
vessel for a short time in boiling water, wiping it im: 
diately before nsing, with a thick cloth. The specimens 
then dropped into this, aovered with the lid, and im: 
diately placed under the receiver of the air-pump, and 
tbe air rapidly exhausted. By this means they are dried 
completely, and so quickly that the calls have no time to 

3. In an hoar or two remove them from the air-^ 
and drop them into a vessel of perfectly transparent cam' 
phine. This may be qnite oo'd when the horny, tobuli 
polypidoma, as those of the Sertnlarite, are used ; but should 
be previonsly heated to 100° when tbe calcareous, cellular 
Polyzoa are the objects to be preserved. Ttie vessel should 
be covered willi a watch-glass and placed under th 
oeiver, the air being exhausted aud re-adiuitted two or three 

4. The slide which is to receive the specimen should be 
well cleaned and warmed so as to allow tbe balsam to flotv 
freely over it. This must be applied in good quantity, and 
air-bubbles removed with the needle-point. Take the poly- 
pidom from the camphgne, drain it a little, and with the 
forceps immerse it fully in the balaam. Tbo glass to be 

ECT9. 103 

laid npon it should be warmed and its eurfaca covered with 
a thin layer of halsam, and then lowered fjradiiallj npon 
it, when no babbles sboald be imprisoned, A narrow- 
piece of card-board at each end of the object, for the 
cover to rest apOD, preventa anj danger of crushing tbo 

This mode of moonting poljpidoraa, &a., aeeraa to gire 
aimoat the complete beauty of tlie fresh specimens. They 
are very beautiful ohjeota when viewed wilh common light, 
but much more so when the polarizer is used (in the tuauuer 
described a little farther on). 

To the above inetructioua there can be little to add ; but, 
I may here mention that some young stadenta may uot be 
posBeeaed of the air-pump, and on this account put aside all 
search for those speoimtna which need litlle looking for at 
the eeaaide. Many of these, however, though tbey lofe some 
beauty by the ordinary mode of drying, will, by steeping for 
Bome time in tarpeutine, not only be freed from the air- 
bubbles, hot suffer so little contraction that they are a 
worthy addition t^ the cabinet. 

Another class of objects is the spkula met with in 
sponges, &a. These are often g!a,sB-like in appearance and 
of various shapes ; many are found resembling needles 
(whence their name); some from tbe syn apt a are anchor- 
like, wbiUt others are star-litte and of complex and almost 
indescribable combinations. As some of these are composed 
of silei and are consequently not injured by the nse.of nitric 
acid, the animal substance may be removed by boiling them 
in it. Those, however, which are calcareous must be treated 
with a strong solution of potash instead ; but whiubever 
way is used, of course they must afterwards be freed from 
every trace of residue by careful washing. 

These spicules may be often found amongst the sand 
which generally accumnlates at the bottom of tiie jars in 
which sponges are kept by those who deal in Ihfm, and 
most be picked out wilh a camel-hair pencil. The speci- 
mens obtained by this meana mill seldom if ever requite 

any cleiLning prociige, as thej are quile free from a 

In tbo former chapttr were noticed ttose insects or parti 
of them whii-h are usaally mounted dry. When they are 
large and too opaqne to admit of the diy treatment, thej 
mast be preserved in Canada balaam or flaid. The first of 
these may now be considered. 

It may be here mentiooed, that with these objects maeh, 
heat must not be employed, as it would in eoaie inatanoea 
give rise to a cloodine^a, and almost invariably injure theiir> 

In killing the insect it ia neoesHary not to rob or brealt 
any part of it. This may be performed by placing it ii 
Kmalt box half filled with fragments of fresh laurel-leave^ 
by immersion in turpentine or strong spirit, as also in boId- 
t.ioDB of various poisonous salts. After which it may t 
preserved for some time in tnrpentioe or other preservativs; 
liquid (Chapter V.) until required. As an assistance to 
Ktudent, I believe that I can do no better than give him 
plan pursned by my friend Mr. Hepworth, wboeo epecimeoi 
are in every nay satihfactory ; but when his method ia useft, 
the insects mast not have been jjlaced in turpentine fot 
preservation : — 

"After destroying the innecta in chloroform or solphnr 
ether (methylated being cheaper), wash them thoronghly il 
a wide-neciied bottle, hair-filled, with two or three waters; 
the delicate ones n quiring great care. Then immerse 
in liquid potash (or Brandixh's solution, which ie strong^ 
than the usual preparation), and let them remain a loDger 
«r shorter time according to their texture. When ready to 
remove, put one by one into a small saucer of clear water, 
and with a camel-hair pencil in each hand press thej 
to the bottom, hofding the head and thorax with the leflr 
hand brush, and apjilyingprtSKUre with the other from abovei. 
downwards, giving the brush a rolling motion, which gene< 
rally expels the contents of the abdomen from the thorax. 
A minute roller of pith or cork might be used instead of the 
brush. In larger objects, use the end of the finger to fiatten 

or jtiCBOEconc objects. 


them. Large objects reqaire more frequent wasliing', aa it ifl 
desirable to remote the potash thoroughly, or crystals are 
apt to form after mounting. Having placed them on the 
Hlidea with thia glass coders, tied down willi thread,* dry 
and immerse them in rectified apirits of terpentine ; place 
the Teasel under the receiver of an air-pump, and keep it 
eihansted until the turpentine has taken the place of tlio 
air-hubhiea ; they are then ready for the application of the 
balsaai. Larger ohjectB may often with advantage he trans- 
ferred to a clean slide, as daring the drying there is con- 
aiderahle contraction, and an outline showing this often 
remains beyond the margin. When closely corked, tliey may 
remain in the spirits two or three months. Aa you take 
them from the hottle, wipe as moch turpentine off aa pnasi- 
hle before removing the thread, and when untied carefolly 
wipe again, placing the finger on one end of the cover whilst 
you wipe the other, and vice versa. By this means yon 
remove as mnch turpentine from nnder the cover as is 
neoessary; then drop the balsam, thinned with chloroform 
(aeo Chapter II.}, upon the slide, letting the fluid touch the 
cover, when it will be taken in between the surfaces by 
capillary attraction ; and after pressing the cover down, it 
may be left to dry, or you may hold the sbde over a Bpirit- 
lamp for a few seconds before pressing down the cover. If 
heat is not applied, they are much longer in drying, hut are 
more transparent. If made too hot, the boiling disarranges 
the ohjectB, and if carried too far, will leave only the resin of 
the baUam, rendering it so brittle that the cover is apt to 
By off by a fall or any jar producing sufficient concussion. 
Never lift the cover up, if possiljle, daring the operation, as 
there is danger of admitting air. A few buiibles may appear 
immediately after moon ting,bat they generally subside after a 
few hoars, being only the chloroform or turpentine in a state 
of Taponr, which becomes condensed." 

D the 

which «ill HI 


This metliod of preparing and mouoting inaecta I can 
ntroDglj recommeod aa giving Grst-rate rcsulLs ; but n' 
the specimpDH are Eioitll, they seldom need tlie soaking in 
canatic potash ivhiah larger ones must hare. It ia oulf 
Dfcesaary to leave them airhilH ia turpentine, especiallf 
when the; have heen first dried nith gentle pressare between 
tiro glas^^es. and then mount with balH&m in the ordinarf 
way. Witli many, even of the larger iuseatB, by soakin; 
them in turpentine or oil of cloves for a longer time, thej- 
are made bo much more transparent and even colourleat, 
us to exhibit their internal organs (which are visible in 
layers, bj the aid of the binocular microsoopp), the mneclea 
of the legs, &c. They become also very beautiful objects for 
the polariacope. 

Amongst the insect tribes there ia abundant employment, 
enpecially for the lower powers of the microscope. Bat if 
the deeper wonders and beauties of the animal eoonomjp 
ere to be songht out and stndied, it ia desirable that thq 
various parts should be set separately, in order that thej 
may receive a more undivided attention, as wel! as 1: 
dered capable of being dealt with under the higher powers^ 
We will therefore briefly consider the treatment which Dtft 
different portions require. 

The eyes of butterflies, and indeed of almost all iusectnl 
afford materials for a study which ia complete in ' 
When examined with a tolerably high power, instead i 
finding each eye with an nnbruken spherical surface, it il 
seen that many are composed of thounnnds of heiagoual 
divisions, each being the outer snrface of a separate portiol 
termed the ocellus. In others these divisions are sqaarei 
but in all there is a layer of dark pigment aurronnding th« 
lower parts. The ocelli may be partly removed from th< 
eye, which will show how their tapering forms are arranged 
But here we have to consider how to place them in baJaait 
for preservation. The eye being reruovcd from the inseoli 
and the dark pigment removed by the use of a camel-h 
pencil, muiit be allowed to remdin in tnrpenline at least tat 



aome daya. The turpentine should then be mnev/ei and 
the eje woU washed in it just before it ia to he mounted. 
It may then be set in halsam in the sEUiio way as any other 
object; — but here a difficolty is mot with. The eye being 
spherical upon the aarface required, most necesaarily be 
" folded " or brcteii in attemptiug to flatten it. This diffi- 
cnlty may be ofttn OTeroome by catting a nainher of slita 
ronnd the edges ; bnt some object to this mode of treatment, 
and, where it ia practicable, it h much more aatisfactoi'y to 
monct one in the natnral ronoded form and another flat. 
Instead, however, of mounting the organ whole, foar or five 
slides may be procured from each of the larger ones, snob as 
those of the dragon-fly, &C, 

The anterejHD also are often mounted on. separate slides, 
aa being better snited for higher poncrs and more minute 
examination than when connected with the insect. These 
two projecting organs, issuing from the head, are jolntBd, 
and moTi'able at will. They difler very much in form 
amongst the varions species, and are well worth the atten- 
tion of the microaoopist. They are nsually mounted with 
the head attached, and perhaps they ace more interesting 
when thus seen. Same few are very opaque ; to prepare 
these the following method has been advised, though it ia 
I'ar better to view them as opaque objects ; — 

Bleach the antenuEo by soaking iu the following solution 
for a day or two : — 

Hydrochloric acid, 10 drops. 

Chlorate of potash, g draohra, 

Water, 1 oz. 

This will render them tranaparent. Wash well, dry, and 
mount in Canada balsam. Instead of the above, a weak 
solution of chloride of lime may be used, by which means 
the nerves will be well shown. Many, however, are rendered 
transparent enough by simply soaking in tarpentine for a 
longer or shorter time. Where the antenna;, however, are 
"Plumose," or feathec-Hke, estreme care ia required in 

moQD ting, though tha difficalty is not so great as so: 

to think. If they are first dried with gentle press 

then anbjected to the action of the air-pamp in a. emaJL ] 

qnantitj of tarpentine until the air is thoroughly expelled, 

tbey can be easily finished npon the slide, especially nhen i 

balsam and chloroform are used. 

Insects Bopply ns trith BDother Beriea of beaotifnl objeot*, 
viz., the feet* Theae are BometimeB simply dfied and 
moanted nithoat any medium, as before mentioned; bat 
most of them are rendered lunch more fit for examination ] 
by using balHam in their preserTation, as it greatly ir 
thoir transparency. The srnaller tiuds may bo dried with J 
gentle presaare betwixt blotting-puper, and then immersed I 
for some daya in turpentine, without requiring the treat* 
ment nith liquor potasea?. This immersion will render them | 
beautifully transparent, when they may be mounted i 
balsam, in the nsual manner. 

It is, however, sometimes found difficult to fix the feet J 
when expanded, in which state the intetcat of the object ia I 
greatly increased. Mr. Balph recommends the followiag ] 
mode : — " First wash the feet, while the insect ia yet aliv% I 
with spirits of wine; then, holding it by a pair of forceps 1 
close to the edge of & clean piece of glees, the insect will I 
lay hold of the npper surface by its foot; suddenly drop>l 
another small piece of glass over it, so as to retain thil foot | 
expanded, and cut it off with a pair of scissors, tie r 
and soak, to get rid of air." Mr. Hepworth says that he J 
never found any difficulty in expanding the loot < 
drop of nater or well-wetted slide, and laying a thin glaaa 1 
cover over it, tying with tbread, drying, and immersing U 

The month, also, with ils organs, 
in many insects. That of the con 
and is comparatively easy to prepare, 
head, the tongue (as it is commonly ten 

n interesting object 1 
1 fiy is often ui 

By pressing the J 
ned) will he forced I 

to protrode, nhen it must be aecared hy the same meana as 
the foot, and maj be subjected to the aoaking in turpentine, 
and moanted as usual. The honey-bee is, however, very 
different in formation, and Ja well worth another elida; 
indeed, even in insects of the same claaa, the differences are 
inanj and interesting. There is anothrr good friend to 
the MioroBcopic Cabinet, the large water-beetle, " Dytieaa 
marginalis" ; and he is by no means nncommon, aa he may 
be met with in many old ponds. If his wings are taken, 
dried, and mounted in balsam, beautifal circles with crossea 
make their appearauoa when examined by the aid of 
polarized light. Bat what are commonly termed his 
Backers are perhaps, bis most popniar gifts. On bis an- 
terior legs will be found small discs attached to central 
members (making the whole an exact resemblance of a boy's 
BHcker), which may be readily cut off, placed on the slide, 
and mounted in balsam. The Dytiaits also gives splendid 
eiamplea of spiracles ; but this will be mentioned where 
dieaection ia treated of. 

Another worthy object of study ia the respiration of 
insects, which ia effuoted by tracheeo or hollow tubes, which 
generally run through the body in one or more large trunks, 
branching ont on every side. These terminate at the sur- 
face in openings, which are termed spiraf.y.s, or breathing 
organs. The lnic}i-e<E often present the appearance of tubes, 
constrncted of a spiral thread, somewhat resembling the 
spiral fibres of some plants. These are very beantifnl 
objects, and are generally mounted in balsam, for which 
reason they are mentioned here ; brft as they evidently 
belong to the dissecting portion, they will be fully treated of 
in another place. 

Amongst the parasitic insects a great variety of micro- 
eoopio subjects will be found. Aa these are nsnally small, 
they may be killed by immersion in apirita of turpentine; 
and, if at all opaqne, may be allowed to remain in the 
liqaid nntil tranaparent enough, and then monntnd in 
Canada balsam. 


The Bcarida, or niAiet and tichs, axe welt known; none; 
perhaps, better than those whicli are ao often fonnd npim 
cheese. Flour, Bugar, figa, and other eatablea are 
iofested hy thera ; whilst the diseases called the itch ii 
and the mange in animala, are prodaced bj creataie 
belonging to this tribe. These insects areaometimeB m 
by simply steeping tham in tnrpentine, and procieding Bl 
with other insects. The Micrographic Dictionary gird 
the following directiona as to monnting pniis of theBe:-^ 
"The parts of the month and the legs, apon whioh tb 
ohnrHoterB are nsnally founded, may be best made oat h 
onishing the animals npon a slide with a thin glass dot 
Bnd washing away the einding substance with water : son 
times hot solntion of potash is requiaite, with the aobaeqnt 
addition of acetic acid, and further washing. When aftet 
wards dried and immereed in Canada balea 
parts become beautifully distinct, and may bo pertnanontl 

Feathers of different kinds of birds are nsnally mounte 
in balHsm when required to show mnch of the strnotuni 
This is particularly interesting when the feathers are «mBl 
as they then show the inner anbstance, or •pith, as it may b 
ternted, with the cells, &c. The " pinnro," or soft brancht 
of the feathers, will be found of various conatructions ; 
possessing hoots along one side, whereby they fasten tfaed 
selves to their neighbours; others branching out, 
straight points somewhat resembling the hairs from cei 
caterpillars. But, of course, when the metallic-lookiu, 
gorgeons colonrs are'all that is required to he showi 
reflected light nsod (as with the ftathers of the hna 
bird, peacock, Slq.), it is mnch better that they should bA 
mounted dry, as in Chapter III. 

The seeds and pollen of plants are most frequently 
mounted dry, as mentioned in Chapter III.; but the mo» 
transparent of the former, andthe darker kinds of tbelatteii 
are perhaps better seen in Canada balsam. There i 
nothing particular to be observed inthemanipulatio. 


"that the glass cover mast be applied lightly, otherwise the 
grains may be crunhed. There are some objects which 
cannot be ehown in a perfect manner when monnted dry, 
but when immersed in balsam become so very transparent 
that they are almost DeelHSB, To avoid this, it has been re- 
commended to stain the objects any coloar that may be con- 
venient, and afterwards monnt iu bakam in the ordinary 

Permanent djea, however, for these minnte oYjects are 
not so readily procurable. My friend Mr. Abbey showed 
me that what was permanent with vegetable matter of one 
kind waa totally nDlrnatworthy with another. The most 
nsefnl that I have tried is Magenta, and the colotir is a 
convenient one. Whatever is nfeci for this pnrposo shoold 
be in solution, and the object steeped fur awhile aud after- 
wards thoroQihlf washed, in order that no superflaons salt 
nay remain. Tnere.are many liquids now sold by every 
chemist which will help the student in this respect. 

Most objects intended for the polariscope may be mounted 
in Canada baii-ain ; but there are some exceptions to this. 
Many of the salts are soluble in this medium, or their forms 
BO injured by it, that glycerine or oil has to be used {see 
Chapter V.) : others inuKt be left in the dry form, as before 
mentioned; and eoaie few it is impossible to preserve tin- 
changed for any length of time. Crystals, however, are 
amongst the most beantiful and interesting subjects for 
polarization ; and it is very probable that, by the aid of the 
polariscope, Dew and valuable facts are yet to bo made 
fcoown. For one who Hods pleasure in form and colour, 
there is a field here which will ouly open wider upon him as 
he advances; aud int^tead of beiog in anywise a merely 
mechanical occopation, it rcqaires deep and careful study. 
The little here said on the subject will shoiv this in some 

With almost every salt the method of cnjetaUization must 
be modified to obtain the beat forms ; I may even go further 
than this, and say that it is possible to change tbeee forma 

112 ritBrMU-TiON asb uqukukg 

to anch a, degree that the eye can perceive no relationahip 
to eiiat between them. If a solution of sulphate of ii 
made, a Bmall quantity spread evenly upon a slide, and then, 
fiufiured to dry whilst in a flat position, the crjstala often 
reBemble the fronda of the common fern in B] Bat if^ 
whilst the liquid is evaporating, it ia kept in motion hj 
stirring with a, thin glaas rod. the crystals form separately^ 
each rhombic piisni having ita angles well defined, and. 
giving beantifol cnlonra with the polarized light, Agai: 
pyro-gallic acid, when allowed to flow evenly over the alid«i 
in a saturated solution, covers the aurface in long needle^ 
which are richly coloured by polarized light; but if any 
Bmall portion of dnst or other mutter should form a nnclens 
aroand which theae needlea may gather, the beauty i 
wonderfully increased. A form very closely resembling th» 
" eye " of the peacock's tail, both m form and colour, is then 
produced, which to one uninitiated in crystallography bear* 
very little resemblance to the original crystal. From theaa. 
aimple facts it will be clearly seen that in this, as in every ' 
other department, study and experience are needful to gin 
the best results. 

Sy dropping a saturated solution of any aalt into alcoh<A! 
— where it is not soluble in the alcohol — crystals i 
stantaneoDsly produced, and the results are often very ourioo^ 
and beantifnl. These crystals can easily be taken np bj K 
pipette — deposited upon a slide, and, after having been 
allowed to dry spontaneously — mounted in balsam. 

To obtain anything liko uniformity in the formation of 
crystals upon the glass slide, every trace of grease must be 
removed by cleaning with liquor potassae or ammonite ii 
mediately before using, care also being taken that none 
the agent is left upon the slide, otherwise it may i 
terrupt and obauge their relative position, and even thelt 

Amongst those which are generally esteemed the most 
beautiful, are the crystals of ozalurate of ammonia. Tbfl 
preparation of this salt froca uric acid and ammonia ia 

ECTS. 113 

rather difficult procesp, nnd will not, on that acconnt.lje do- 
scribed here; bnfc when poesegaed, a small qaaotity of a 
strong solution in watar must he made, and a little placed 
a the slide, and evaporated elowlj. Part of the salt will 
then be deposited in circles with the needle-like crystals 
eitending from common centres. They Hhoold then be 
monnted in pare Canada balsam ; and, when the beet coloors 
are wanted, nsed with the eeli'nite plate. Of this cIbbb of 
crystal, salicine is a aniver^al favourite, and can he easily 
procured of most chemists. The crystals may he produced 
'n two ways ; — A small portion of the salt niust be placed 
upon the slide, and a strong heat applied underneath nntil 
fusion ensues ; the matter should then be evenly and thinly 
spread over the surface. In a short time the crystals will 
form, and are generally larger than those procured bj the 
following process ; but the uncertainty is increased a little 
when fusion is used, which, bowever, is desirable with many 
Bait?. Secondly, make a saturated solution of salicioe, 
vhich is effected by boiling one part of the salt in eigLteen 
of water, and allowing it to cool. Place a little upon the 
slide, and let it evaporate spontaneonHly, or with the aid of 
gentle heat. The crystals are generally uniform, and with 
ordinary powers quite large enough to make a beautiful 
object. Their circular shape and gorgeous colours — ^even 
without a selenite plate — have made them such great 
favonrites that there are few cabinets without thtm. 

There are also some salts which are crystallized in a some- 
what different manner from those before mentioned. San- 
lonine ie one of the most beautiful, snd will illustrate my 
meaning. Place a small portion upon a slide, and heat over 
a lamp nntil it is fused. With a hot needle spread the salt 
over the surface required. As the slide cools, the formation 
of crystals tak^ place, nntil it becomes one mass. This 
Bait ia slightly soluble in the ordinary balsam, end should 
be mounted in castor oil. If, however, the slide is well 
eovered under the thin glass, the balsam soon becomeB 
saturated, and very little injury results. According to the 


temperalure daring crjetallizatioa the character of th» 
crystals is affected. If the fused kbII is very hut, the crjataU. 
run in straight Ilucb from a oommon csotre. If tba heat il 
(irhat I roaj term) medium, the crystals show ODDoentria 
waves of verj decided form. IF the slide is conl, the crfstals, 
still concentric, are oiceedingly minate. The most beautiful 
crystals for the niicroBcopist are thoBB formed at a tern- 
pcratare betwiit the second and third above mentioned, t 
the minote and wavy forms are thea combioed, and 1od{(, 
feathery crystals are the rosnlt. Aa this method reqairei, 
some little practice, many crystallize the salt in a simplet 
manner, which I will give ; but the variations obtainable* 
by fusion give that mode the precedence. Dissolve a fevi 
grains of suntonine in a drachm of chloroform, and drop the 
Eolotion npon a glass slide. Allow the liquid to evaporat^, 
and beaatil'ul crystals will be the resnlt. Mount as above. 

In fear of being somewhat uninteresting to part of my 
readers, T feel aa tbongh I should not be fulfilling my desire, 
of giving every information, if I omitted to show another 
method of crystallisation, which a novice would cast awa^ 
88 a failure before he had completed hia eqjeriment. Tartrate 
of soda, made by neutralizing a strong solution of tartario 
acid by the addition of carbonate of soda, is spread in so1n« 
tion over a glass slide, and must be then warmed, but not 
lioilad. It must now be laid in a dry place, protected from. 
all chance of dnst. In time — from one or two days to a 
many weeks — Bome of the slides will prove beautiful objeots,, 
showing the cross form surrounded by rajs, Someof thes 
slides never crystallize, thongh I can lind no reason for this,, 
and even the application of heat to these calls out no decided. 

Hippuric acid will be found moat interesting to those who 
are fond of beautiful polariscopio effects, inasmncU a 
salt is capable of giving an afitounding variety in the forms 
of its crystals. Make a saturated solution in absolote 
aicohol, and use it warm; by dropping a small quantity 
irou] a warm pipette on to a warm slide a film will spread 


IT tbe slido and orystala of a. oircnlar form will licgin to 
jear, and may be modified by the atmosphere in which 
they are allowed to grow ; tbua a moiat atmoaphere oi the 
e?erse, an atmosphere of vapour of ammonia, apirit, ben^tole, 
c aulphureous famea, will eaah prodnce a different resnlt, 
and the modifications thos produced will afford food for very 
Mrioaa reflection on the changes one aalt maj ba made to 
'n contact with other agents. These crystals are 
■faest mounted in castor oil — hnlaam that is very liqnid — 
tiot balsam in baiKiole, as tbe henzole changea the character 
of the crystal. 

Many new forms may he procured by nniting two totally 
differeat salts in solation in certain proportions. This ia a 
field affording new facts and beaaties ; but requires some 
chemioal knowledge and much perseTeraoce to obtain very 
valoable results. Ooe of the most beautiful I have met 
with baa been composed of sulphate of copper and aalphate 
of magnesia. The flower-like forma and uniformity of 
cryatallizatios wlien Buccosfifiil mnko it well worth a few 
a at first ; and as I became acquainted with some new 
facts in my freqnent trials, I will give the preparation of the 
double salt from the begioniog. 

Make a saturated solution of the two sulphates, combined 
a the proportion of three parts copper to one part mag- 
nesia, and then add to the solution one-tenth of pure water. 
.ITo dnat or other impurities should have access to the slide, 
Bud it should be freed from all traces of grease by cleaniuf; 
'mmediately before use with liquor potassffl or ammouirB. A 
drop of the solation should then be placed upon it, and by 
a thin glass rod spread evenly upon the surface. Heat 
this whilst in a horizontal position until the aalt remains as 
e transparent substance, which will not be effected 
until it ifi raised to a high degree. The slide may now be 
allowed to cool, and when this ia accomplished, tbe flower- 
like crystals will be perceived forming here and there upon 
the plate. When these are at an; stage in which it is 
wished to preserve tliem, a few seconds' exposure to the fire. 

118 ruEriHiTioN and modntikg 

cooliing, the Boales may be easily taken froi 
Bnrface. Tbey maat then be waabed and tborongblj 
cleaned. After drying, eoak for a day in tar]>entine, 
monnt in the ordinary manner with balsam. This 
good polarizing object ; but the intereat, and I think thi 
beauty, is inoreaaed by procuring a piece of eel'a skin with 
the scales in silu, waahing and drying ttnder preaenre, s 
monnting in balsam as before. The arrangement of i 
BcaleB produces beaatiful " waves " of colour, whioU i 
quite soothing to the eye after eiamining some of tbe vi 
gorgeons eaJta. 

Tiiere are many scales of fish which are good fiubjeets 
the polariscope when moanted in balsam ; but as they 
qoire no particular trodtment, they need 

Among haira we find some wbicb are beantifnl nhel 
monnted in balsam and examined by polarized light. Sam^ 
when wanted as common objects, are always nsed dry, a 
bcfure mentioned ; but if they are intended to be shov 
jiolarjzing objects, they most be placed in some medino. 
The Micrographic Bictionary mentions a mode of makini 
an interesting object by plaiting two aeries of white 
hairs at an angle, mounting in balsam, and nsing with ttU 
polariscope. All haira, however, mast be steeped i 
pentine for a short time before mounting, as they will thqB' 
be rendered cleaner and more transparent. When this ii 
done, there is no difficulty in mounting them. 

Many of the "tongues" of fresh-water and 
mollosca are deeply interesting and most beaiitifol objefl 
when examined by polarized light. As these are nsaallj 
mounted in balsam, I mention them in this place; ' 
they must be removed from tbe animals by dissection, 
particnlars respecting them will not be entered into i 
we come lo the part in which that operation ia deacribact 
(Chapter Vf.). 

The manner of preparing and moanticg many of thM 
f olyzoa and Zoophytes has been before described ; but atg 


notice of polariainff objecta would be incomplete wilhoot 
BomB allnaion to them. A small jiieoe t^f the Flutitra 
oviculaTis, well prepured, ia beautiful when examinoJ in 
thia manner. No Helenite ia needed, and jet the coloura 
are truly gorgeoas. It ia often met witli upon shells and 
zoophjtea of a larj^e size, and will well repay the trouble 
of Bearching for. Many of the Sertularidio are very beau- 
tiful with polarized light, and, indeeJ, no ramble upon the 
seaaide need be fruitless in this direction. 

The different s(ui'c?ics are quite a study in themielvea, 
and are peculiarly connected with polarized light. Thoy 
are found in the cellular tisane of almost every plant in 
amall white grains, which vary considerably in size; that 
from the potato averages one- three- hundredth of an inch in 
diameter, and that from arrow-root about one-aii-hundredth. 
To procure starch from any plant, the texture must first be 
broken up or ground conreely ; the mass of matter muHt be 
then well washed in gently-flowing water, and, as all starch 
is totally insoluble in cold water, the grains are curried off 
by the cnrrent and deposited where this is stayed. In pro- 
coring it from the potato, as well as many other vegetableF, 
it is hot necessary to reduce the substance to a coarse pulp 
by the aid of a culinary grater ; the pulp should then be 
well agitated in water, and allowed to rest a short time, 
when the (.tarch will be fonod at the bottom, its lighter 
colour reodering it easily distinguish able from the pulp. It 
should, however, be washed through two or three waters to 
render it perfectly clean. 

These grains have no crystalline strncture, but present a 
Tery peculiar appearance when eiamincd with polarized 
light. Each grain shows a dark cross whose lines meet at 
the point where it was attached to tbe plant, called the 
hllnm. Round the grain also a series of tines is seen, ae 
thoDgb it were pot together in plates. This ia more die- 
tinctly visible in some binds than othere. 

As to the mounting of these starches there is little to be 
said. If the grains are kid Dpon the slide, and as (jidbII a 


portion as possible of the balsam dilnted with tnrpentine, 
as before mentioned, be applied, they will cling to the glass 
and el11ou7 the pnre balsam to How readily over them with- 
cint being bo liable to imprison air-bubbles when the thia | 
glass is put upon them. 

The raphides, which were fully described in Chapter in., ' 
when required for use with polariied light, must be monnted | 
in balsam, and many are fonnd which gire beautiful coloi: 
They require no peculiar treatment, but must be washttd '] 
quite clean before putting np. But in order to onderatand \ 
anything of the natural arrangement of mplddee, 
necessary to mount certain parts of plants with these olijecta I 
in bIIu. The most common is the coating of the onion, 
which moBt be soaited aouie time in tnrpentine or benzole, 
in order to render it transparent, and must then be moiinted 1 
in balsam, as before said. We abflll then be able to oblaia I 
such colours by the aid of polarized light, that the rapliides 
are shown in wonderful distinctness, and somewhat of their j 
natnre will be perceived. 

There is one class of objects for the polariscope whioli 1 
diSers in preparation from any we have yet considered, and j 
affords very beautiful specimens. Same of the plants, in- 1 
eluding many of the grasses and the Eqnisetacece [i.e. hoise- .1 
tails), contain so large a qnantity of silica, that when the J 
vegetable and other perishable parts are removed, a sVeleton I 
of wonderfnl perfection remains. This slieleton must bs J 
monnted in balsam, the method of performing which v 
now be considered. 

Sometimes the cuticle of the equlsetnm is removed from ] 
the plant, others dry the stem under pressure, whilst tha I 
grasses, of con rse, require no aucb preparation. They should ] 
then be immersed in strong nitric acid and boiled for a ] 
short time ; an effervescence will go on as the organio matter j 
is decomposed, and when this has ceased, more acid should I 
be added. At thia point the modes of treatment diSer;.] 
Borne remove the object from the acid and wash, and having J 


dried, burn it npon thin glaea until all appeara mhite, when 
it mnst bi> carefully mounted in balsam. I think, however, 
it ia better to Jeaye it in strong acid until all tlie Bubatanoe, 
except the required portion, ia removed; but this will take 
a length of time, varjio^ according to the mass of the 
plant. Of course, when tbia latter method ia need, the 
akeleton most be washed from the acid, &c., before being 
mounted in balaaro. 

Theae sitkeoua ctttides are readily found. The straws of 
most of the cereals, wheat, oat, &c. ; the hiiska, alao, of Bome 
of theae ; many canes ; the equiaetnm, as before described ; 
and some of the graases. Muny of theae are everywhere 
procurable, so that the atudent can never want material fur 
& splendid object for the polariacope. 

In Chapter III. the scales (or baira) which are often fonnd 
upon the leaves of plants were mentioned as beautiful olijects 
when mounted dry; bat some of theae when detached from 
the leaf — which is easily done by gently scraping it, when 
dried, with a kiiife — present brilliant starlike and other 
forma, if mounted in bataam and used nilh the polariscope. 
There is a little danger, when placing the thin glass upon 
the balaam, of forcing out the scalea in the wave of matter 
which ia always ejected; this may be overcome by applying 
to the elide, previously to placing the objects upon it, aa 
extremely thta coveriag of balsam diluted with turpentine 
as before mentioned, letting it dry more or leas with the 
objects placed in it, and then, after the addition of a little 
more balaam, putting the cover on, and thus giving tbeoi 
every chance of adherence ; or by uaing the balsam with 
chloroform, as before noticed. This method is peoaliarly 
Buc<iessful in cases where it is desired to arrange several 
objects symmetrically on a slide, and to obviate their sub- 
Beqoent diaturbance by placing the cover on. Tjpe slides 
with several parts of an insect diaplayed upon them, sealea 
of fiah, or of plants, &o., way thus be shown, eo that the 
numier of elides may by this plan be seriouely diminished. 


These scales are much more abandant than was formerly 
snpposed, and new specimens are discovered daily; so that 
the Btudent shonld always be on the look-oat for them in 
his researches in the vegetable world. 

Most classes of objects, and the treatment they require 
when monntiog them in balsam, have now been considered. 
The next chapter will be devoted to preservative liquids, 
and the best method of nsing them. 

F MicaoscoPic OBJECTS, 




TirzRB are many objecta wliicli woa1d lose all their distinc- 
tive peonliarities if allowed to become dry, e9]>ecially those 
belonging to the fresh-irater Aigai, many animal tissaes, 
and moat of ths very delicate Bnimal and vegetable sub- 
Btances in wbich structure is to be sbown. These must be 
preserved by immersion in some flnid ; but it is evident that 
tbe fluid must be saited to the liind of matter nhich it is 
intended to preserve. Aa it often requires ranch study and 
trouble to obtain microscopic objects of this class, it is well 
that their 'preamtation should be rendered as perfect aa 
possible ; arid for this reason the cells, or receptacles of the 
fluids, should be ao closed that all possibility of escape 
should be prevented. The acconfiplisbment of this is not so 
easy a matter as it might appear to tbe inexperienced. 

Before giving any directions as to the manipulation 
required in mounting the objects, wo must consider the 
difierent liquids and cdia which are requisite for their pre- 
servation. Of the former there are a great nnmber, of which 
the principal way be mentioned. 

Distilled Water is strongly recommended by many for 
Diatomacere and other Protopbytes. It has been, however, 
atated that confervold growths cften disturb the clearness 
of tbe liquid, and on this acoonnt various additions are made 
to it. A Jump of camphor is often left in the bottle, so that 
the water may dissolve aa much as poBBible. One grain of 
bay salt and one of alum are added to each onnce of water; 
or a drop or two of creosote shnlien up with an ounce of 
water, which should be afterwards filtered. These additiooa 


are often made; perhaps each of them good for certain 

Glycerine. — Some affirm this to be one of the best pre- 
servative liquids, especially for vegetable objects ; bat others 
think that it is much better when diluted with two parts of 
camphor-water, prepared as above.* Mr. A. E. Yerrill, of 
Yale College, U.S., says glycerine preserves the natural 
colours of marine animals ; and the only pr^ecaution to be 
taken is to use very heavy glycerine, and to keep up the 
strength by transferring the specimens to new as soon as 
they have given out water enough to weaken it much, re- 
peating the transfer till all the water is removed before 
finally mounting on the slide. 

Glycerixe and Gum. — This is also believed to be a very 
good liquid for vegetable tissues, and is thus prepared : — 

Pure gum-arabic... 1 oz. 

Glycerine 1 „ 

Water (distilled)... 1 „ 

Arsenious acid ... 1^ grain. 
Dissolve the arsenious acid in the cold water, then the gum, 
add the glycerine, and mix without bubbles. 

Dr. Carpenter states that the proportions used ultimately 
by the late Mr. Farrants are : — 

Picked gum-arabic ... 4 parts by weight. 
Distilled water (cold).. 4 „ 
Glycerine 2 

Thus he now omits the arsenious acid, but places in the 
solution (which should be kept in a bottle with glass stop- 

* Dr. Carpenter says : — "Glycerine has a solvent power for carbo- 
nate of lime, and should not be employed when the object contains 
any calcareous structure. In ignorance of this fact, the author (Dr. 
C.) employed glycerine to preserve a number of remarkably fine speci- 
mens of the pentacrinoid larva of the Comatula, whose colours he was 
anxious to retain ; and was extremely vexed to find, when about to 
mount them, that their calcareous skeletons had so entirely disap- 
peared, that the specimens were completely ruined." 

99 it 

OF jJicEosconc 

I per) a amall piece of camphor. This requires no cell, as the 
adheBive power is aufficient. 

Dbakk's Compound, — This is uaiially deemed al>out the 
best medium for preserving Algie, mnsaec, Ac, and ia thos 
prepared ; — Soak 1 oz. of best gelatine ia 4 oz. of water 
until the gelatine becomes soft, when 5 oz. of honej hented 
to boiling point are added i boil the mixture, and whea it 
hae cooled, but not enongh to become stiff, add g oz. recti- 
fied spirit with which 5 or 6 drops of creoaote have been 
well miied, and filter the whole through, fine flannel. Thia 

mpound when cold forms a at iff j el ij, the use of which 
will be described elsewhere. 

Glvcekinb Jellv. — This miitnre closelj resembles the 
ftbove, but aa the composition differs a. little it may be men- 
tioned here. It ia atrongly reoommeinled by Mr. Lawrance 
the MicroBctipic JouTnal, where he states " tliat the 
beantiful green of some mosBes mounted two years ago, is still 
as fresh as on the day they were gathered ;" and that thia 
ia the only mediam he bDows which will preserve the natoral 
colonr of vegetable aobetaoces. He takes a quantity of 
Nelson's gelatine, soaks it for two or three hours in cold 
water, poura off the supcrflaous water, and heats the soaked 
gelatine until melted. To each fluid ounce of the gelatine, 
tehilet it ia fluid hut cool, he adds a fluid drachm of the 
vrhite of an egg. He then boila tliis until the albumen 
coagulates and the gelatine is quite clear, when it is to be 
filtered througKfine flannel, and to each ounce of the clari- 
fied solution add 6 drachms of a, mixture composed one part 
of glycerine to two parts of camphor- water. 

At. the Academy of Natural Sciences of Philadelphia, 
Mr. W. H. "Walmaley stated, that, owing to the beat of that 
climate, the above formula for glycerine jelly was sot satis- 
factory, and recommended the. following : — Take one pack- 
age of Cos's gelatine, wash repeatedly in cold water; allow 
it to soak in water sufKoient to cover it for an hour or two, 
add one pint of boiling water, and boil ten or fifteen 
minutes. Bemove, and when cool but alill fluid, add the 

i the 


nhite of an egg, vrell boaten, and agaiu boil, until the albu- 
men coegutatea. Strain TChilst bot tbrougli flaoDel, and 
add nil equal imrtion by meaBurement of Bowyer'B pnre 
glycerine, and fifty drops of carbolic acid in Bolnlion; boil 
again for ten or iifteen minatee, and again Btrnin through 
flannel, place in a wat«r-bath and evaporate to about one- 
half, thcQ filter into two or more broad- mo othed vials, (Cotton 
IB the beat filtering msdium.) The use of thia in mounting 
is the same na Mr. Lawrance'e, elsewhere described. 

GoiDBi's Fluid. — This is much naed in the preservation 
of animal objects ; and seldom, if ever, acts upon the colours.- 
It ia thns prepared :— Bay salt, 4 ox. ; alum, 2 oz.; con " 
eablimate, i grains. Uisaolve these in two quarts of boiling 
water, end filter. For delicate preparations eonie recom- 
mend that this mixture be reduced by the addition of an 
equal quantity of water; hut where there ia hone or shell ia 
the ohjfct, the above acts injurioualy upon it, in which casa 
this fiuid may be used: — Bay salt, 8 oz. ; corrosive auhli- 
mate, 2 grains ; water, 1 quart. 

Thwaiteb's Liquid. — This ia recommended for the preeer-. 
vation of Algm, &a., as having little or no action oi 
colour, and ia thua prepared ;— Take one part of rectified 
spirit, add drops of creosote enough to saturate it; to thii. 
add sixteen parta of distilled water and a little prepared' 
chalk, and filter. When filtered, mix with an equal quantity 
of eamphor-water (as before mentioned), and strain throogh. 
fine muslin before using. 

Chloride of Zinc SoLniON. — In the Micrographic Dic- 
tionary thia ia stated to be " perhaps the beat preaervativfti 
known for animal tisanes." Persons of great experienoa, 
however, have given a very different opinion; but it U 
tainly very useful in many cases where a small degi 
coagulating action is not injuriou;!. It is used of etrengthi 
varying according to the softness of the parts to be pre- 
served ; the average being 20 grains of the fused chloride to 
1 oz, of distilled water. To keep thia liquid, a lump uf 
phor may bo left floating ia the bottle. I have heard 

lainta that tbia Tnixtura bccomea turbid with keeping; b'lt 
thio^ thia must onlj be tlie case v/hea eome impiirilj lia^ 
g;ot into the bottli;. 

Cmibolic Acid.* — The addition of a fow dropa of thia to 
distilled water prevoats the growth of interferiog' subatancoa 
iwhioh woold take place if pure water alone were used, aai 
IB therefore valuable as a preaervative fluid. The same 
tolntion also ia coDvenient, aa it iuatautly kilja iufaaoria, and 
lilinoat everything that haa life; and, iodeed, is nseful in 
tJie atndeut'a gathering-bottles for the same reason. It ia 
»ery highly apobea of aa forming one of the coustituenta in 
following formula for use in mounting aoft animal 
jMtnrea ; — 

Araenious acid, 20 parta, 
CryfitalliKed carbolic acid, 10 parta. 
Alcohol, 300 parta. 
Distilled water, "00 parts. 

The Rav. "W. W. Spicer, in his tranalation of Johami 
Kave'e work on Atgie. recommpiida the following fluid for 
their preaervation : — Pnre alcohol, 3 parts ; distilled water, 
S parta i glycerine, 1 part. If the deamid or other alga 
fee placed in this fluid in a cell, and not covered by a glaas 
time, the water and alcohol will evaporate slowly, and 
the mixture wiU become more dense in proportion, hot quite 
'gradaally, and therefore without any destriictife influence 
on the object. During this operation, water is withdrawn 
from the frnatule, a.ud the glycerine, which ia not volatile, 
takes its place without causing any distortion of the abject. 

Castor Oil.— Thia is a very useful preservative for 
Ctystals and other objects. Many salts are quite destroyed 
when Oauada balsam ia uaed with them; but very few are 
acted upon by this oil. To use it, it must be dropped in 
AufScieut quantity to coTer the crystal or objt'ct to bo 

Ctroo Calvert stated at a. meoting of the British AaaooiatioD, 
that af Mr oaroful expariiuenta he finds oarbulio biid " prorenta tlia 
" LYelopmaot of protoplaamiu and fungoid lifB." 

128 rEErjEiTios and uocktiss 

presevTeJ wilh a. thin coating of oil. It may be neoeaaafy 
Bometimes to spread it with a needle or other inBtrnment, 
The thin glass shonld Ihcn be carefnllj placed upon it, W 
thitt all air may be excluded ; and shoald aiDj oil be foiitA 
oat, owing to the quantitj used being too great, it mai ' 
be remOTsJ with blotting-paper. When the edge of tl 
thin glass cover and tbe enrrouBding parte of the elidfl a: 
as clean as possible, a coating of Bealiog-waz varnish ( 
liqnid glue most be applied and allowed to dry. A eeooni 
or even a third coating may be required, but not before tli 
previous cover is quite dry. These varnishes, however, a 
very brittle, and it is much safer, as a fiuish, to nse one 
the tougher cements — gold-size, for instance — which w 
reader it doubly secure. 

Tbe above are the principal liquids. &o., used for pre 
eerving objects in cells. The different cells may be h 
mentioned ; and it is recommended that these should alwayi 
be kept some time before oBe in order that the ceniei 
become perfectly dry; and care mast be taken that n 
cement be need on wbich the preservative liquid employo 
has any action whatever. 

Cehest Cblis.^ Where the object is not very thick, tl 
kind of cell is generally used. They are easily made vri 
the turntable before described ; but when the objeets to ti 
preserved are very minute, these cells need not be t 
deeper than the ordinary circle of cement on tbe siicil 
When, however, a comparatively great depth is required, i 
is sometimes necessary to make the wall of the cell as de^ 
as possible, then allow it to dry and make another additiol 
Of these cements gold-size is one of the most truatwortlfl 
and may be readily used for the shallow cells. The 
phaltum and india-rubber, before noticed, I have fonod vi 
durable when well baked, and exceedingly pleasant to wi 
witb. It may be used of such a thickness as to give spu 
for tolerably large objects. Black japan also ie tanch a 
Many cements, however, which are recomniended by bi 
ivriterB, are worse than oselesa, owing to the brittkness wl 

ECis. 129 

anSera their durability uncertain, a,s eeaJing-wai, vamiah, 
liqnid-glae, &c. Dr. BaHliau says the best cement for liquid 
cells is one, much used in Germany, made by adding a. 
considerable qaantitj of nitrate of bisuiuth to a solutiou ot 
gam mastic in chloroform. It can bo procured at almost 
any optioiao'a. 

The Btndent may feel himself at a Ions in choofing the 
'Cement which will give him. the soj'tsl cells, many of them 
becoming partially or wholly dry in a year or two. aa stated 
in another place. I can only give him a few general direc- 
iiona, and he muat then uae his own jadgment. Of coar^o 
it would be lost labour to employ any cement upon which 
the prCBeryntiTe liquid has aiiy adiuri KhaUum: It ia alao 
a good rule to avoid thoae in nhoae compoaition there arc 
MDJ particles wliich do not become a thorough and intimate 
.portion, as thesa nnreduced fragments will almost certainly, 
«oODer or later, prepare a road by which the liqaid will 
jssoape ; and, lastly, whatever oemeut he uses, the cdla are 

KIwaye better when they have been kept a short time before 

GoTTA-FEBCJTi R[KGS have been recommended by some, 
«B affording every facility for the manufactnte of cells for 
liqaida i bnt they cannot be reoominended, aa, after a certain 
length of time, they become ao brittle as to afford no safe- 
guard against ordinary acuidenta. Some have also used 
india-rubber baada thickly coated with various varnishea ; 
Ijnt theao I consider leas trust-worthy than gatta- 
Jiercha, aa they become tlioroughly rotten in ordinary 
oae after a short probation, 

Olten the cells must necessarily be of a large size, and 
Sot this reason are made by taking four strips of glass of the 
thicknesa and depth required, and gribding the places where 
these are to meet with emery, so as to form a slightly 
roughened but Sat edge. The glass atrip must also be 
ground DU the side where it meets the plate, and each piece 
cemented with the marine-glue mentioned in Chapter II in 
the following manner ;— On that part of the glass lo which 


another piece U to bo attached shoTild be laid thin strip ot 
tbe glue ; both pieces mnat thea be heAted upon a enlU 
brass table, witb the aid of the spirit-lamp, until the etripa 
become melted ; tbe small piece is then to be taken ap isi 
placed upon the epot to trhich it is to be attached, and H 
on nntil the cell is completed. It will be found necessHrf to 
spread the glue over the anrface required with a needle or 
some other in str am eut, 00 that an nnbroken line majbt 
preaeoted to the wall of the ceil, and no bobbles hmA 
Too gveat a heat will burn the marine-glue, and render it 
brittle ; care must be therefore taken to avoid this. 

When shallow cells are required, those which are mad* 
by grinding a concavity in the middle of an ordinary slii* 
will be found very convenient. The concavities aieoutbora 
circular and oblong ; and the surface being flat, the ot 
easily fastened upon it. These are now cheap, and ar 
safe as to leakage. It is a very great improvement, 
it can be done, to turn a shallow ring outside the ooncaritf 
of the slide, but close to it. This prevents the cemei 
■which the cover is fastened from running in. 

Circular cells with a flat bottom used to be made If 
drilling a hole through glass of the required thtckneas, <M 
flxing this npou an ordinary slide with marine-glae; ^^ 
the danger of breakage and the labour were so great thri^ 
this method is seldom used now, and, indeed, the rings 
to be mentioned do away with all necessity lor it. 

Glass Eings. — Where any depth is required, no methflS 
of making a cell for liquids is so convenient as the nae (£ 
glaaa rings, which are now easily and cheaply proonraUt 
They are made of almost every size and depth, and, ejusp 
in very eitraordinary cases, the neeessitj for building 
is completely obviated. These rings have both edges 
rough, and consequently adhere very well to the slide, 
adherence being generally accomplished by the aii 
marine-glue, as before noticed with the glass cells. Gol3* 
size has been occasionally used for this purpose; and WW 
adherence, even with liquid in the cell, I have alwaye {oaoi 



to be perfect. This method has the advantage of requiring 
no heat, bat the gold-size mnat be perfectij dry, and the 
ring mast have been liied apon tlie shde Bome time before 
nae. Canada baUara has also been naed for the same 
porpoae, but cannot be recommended, as, when it ia perfectly 
dry, it becomes eo brittle as to bear no shock to which the 
slide may be ordinarily exposed. 

Iron Ersos.^ — Many have worked with these, having 
taken care to varnish thoroughly bel'ore using with any 
preservative liquid ; bat they are always untruatworthy, as 
they can never be guaranteed against the action of some salt 
ID the liquid used. They can be procured beautifully made, 
and for dnj cells cannot be surpassed. Zinc and pure tin 
rings may alao be procured, and are eicellent, especially Iba 

YcLCisiTE. — Thifl Bubatanco is a great favourite with 
Borne of our working raicroaoopiste, aa it is very slightly in- 
flaenced by change of temperature. But my owa opiaion ia 
that a glass cell ia the safest and most satisfautory re- 
ceptacle for any object in liquid, and if carefully prepared 
will not deceive the operator. 

Theae are the cells which are mostly need in this branch 
of microaaopic mounting. The mode of using them, and the 
different treatment wbioh certain objecta require when in- 
tended to be preserved in the before- mentioned liquids, may 
now be inquired into. 

I may mention, however, that thia class of objects is 
looted upon by many with great mistrust, owing to the 
'danger there is of bubbles arising in the cells after the 
mounting has been completed, even for years. I know some 
excellent microscopists who exclude all objects in cells and 
preservative liquids from their cabinets, because they say 
that eventually almost all become dry and worthless; and 
is no matter of surprise, for many of them do really 
become so. Purbaps this is owing to the slides being sold 
before they could possibly be tboronghly dry. As to the 
air-babbles, I shall have something to say presently. 

ir« wa Mv ■ifiiii «» 

kr pUiK * eh* liiv ^« tk. riidt Wu ■ 

Ikv ^taM vUck is la «Bmr a, I tnM witlt « d 
ptBtfl * tiag flf gaU-M^ ■■! kbo anond tlie edge Of fl 
«dl la Bhick ft M to ■bcR^ Dr. CtarpcBtcr objeeta lo Hal, 
m i M JaJ w g tk bi« f p licatin M oT Ura gdd-nse liaUa t( 
■*m IB.' A8 diagir af 1U^ bowenr, u MnnjtletelT oh-- 
visted hf JMiiog tfce AAe aad eoFer for awhile nn^ Um 
ctf t bewea fsctUlj' fised, bat still adhesive enimglL 
to peHbrw its baetioa (Chapter III.). With many sltdM 
tUi it aot mttnmfSAri ia lea tbaa twealj-foar boors, evei 
if left two or tkm daj« bo tnjaiy whaterer eaeaeB; ba 
with other ktoda bb boor ia too long to 1«are Use 
cement, co tbst tbe openttv must use hia own di 
It is not alwaja necessuj to aiie tbe edge of the cover 
■ince pCTftct adhfeian mtj in maoj cases be seexsied witb 
oat it. and it is always beat to use tbe leaat qaantitj d 
eement tbat will answer, as it will then be less likely to n 
in. The liquid reqaited ma; be drawn up b; the men 
into tbe pointed tube neDtioDed in Chapter II., and th 
transferred to tbe cell. In the Tarions booba of instructioB 
tbe oliject ia now to be placed in tbe cell ; this, howi 
think a great mistake, as another process is abBoIatel 
oeceBsary before we adviince so far. The cell, full of liqnii 
mnat he placed ooder the rsceirer of an air-pump, and th 
air withdraon. Almost immediately it will he perceive* 
that the bottom and sides of the celt are covered with mionttf 
bnhblee, which are formed by the air that is held ii 
pension by the liquid. The slide may now he removed, ancl 
the bubhleB may require the aid of a needle or other 
to displace them, so ohatinately do they adhere t 
surface of the glass. This process may then be repeatedr 
and one canse, at leaaf, of the appearance of hubbies in oeHs 
of liquid will be removed. The object to he mounted ahooH 
alio he soaked in one or two changea of the preservativfl 
liqnld omplojed, ond, during the aoakbg, he placed under 

OF MicKOscoric OBJECTS. 133 

tlie air-pamp and exhansted. It may then be transferred 
to the cell, aad nill probably cansB the liqaid to averflov a 
little. Tbe cover with the golJ-aize applied to the edge 
taoBt then be careFitUj laid upon the cell, and sligbtlj 
presaed down, ho that all air-bubblesmay be displaced. The 
two portions of gold-eize irill now be found to adhere 
nherever tbe liquid does not remain, althongb the whole 
ring may have been pre»ionsly wet. The outer edge of tbe 
thin gUsB and cell must now be perfectly dried, and a 
coating of gold-size applied. When thia is dry, the procesa 
mnet be repeated nntil tbe cemeot baa body enough to pro- 
tect the cell from all danger of leakage. When aome pre- 
servative liqnida are used, a scum is frequently found upon 
tbe Burface when it is placed in the cell, and this must 
be removed immediately before the cover is laid upon it. 

I believe this method to be perfectly secure against 
leakage when carefally performed ; and some of my friends 
have told roe that their experience (that of some years) has 
been equally a atia factory. 

In using soma of the particular kinds of preservative 
liquids, it tviU bo fonnd necessary to make a eligbt change 
in the manipulation. This will be best explained by mention- 
ing a feiv objects, and tbe treatment tbe; require. 

For the preservation of the Mosses, Algna, &a., Deane'a 
compound ia much used, and considered one of the best 
media. The specimen to be mounted should be immersed 
in tbe compound, which must be kept fluid by the vessel 
containing it being placed in bot water. In this state the 
whole should be aubmitted to the action of tbe air-pump, as 
it is not an easy matter to get rid of the bubbles wbicb form 
in and aronnd tbe objects. The cell and slide mnat be 
warmed ; and heat will also be necessary to render the 
gelatine, ifec, fluid enough to flow from the stock-bottle. 
The cell may then be hlled with tbe compound, and the 
Bpecimen immersed in it. A thin glass cover ranst then be 
vfaimed, or gently breuthed upon, and gradually lowered 
upon the coll, taking care, as with all liquids, that uo 


bubble* are formed bj tha operation. The cover may be 
fixed by the &id of gold-size, Japan, or any of the neiial 
TamifiheB, care being taken, as before, that all tbe compoaad 
IB removed from the parts to nbich the varaieb is intended. 
t« adhere. 

The glycerine jelly of Mr. Lawrance, before mentiondt 
reqnireH atmoet a aimilar treatment. " The object* to U 
mounted in this medium afaoald be iminersed for aoine tinu 
in a mixture of eqaal parts of glycerine and dilate alcohol' 
(six of water to one of alcohol). The bottle of glycerine jelly 
maet be placed in a cop of hot water nntil liqnefied, when it 
moBt be need like Canada balsam, except that it reqniM 
lees heat. A ring of aspbaltam varnisb roand tbe thin glu4 
cover completes tbe mounting." 

The Infusoria {aee Chapter IV.) are aometimes preserved 
in liquid; bat present many difficnlties to tbe stadent, 
Different kinds require different treatment, and conseqaently 
it is well, when practicable, to moant similar objects in twq 
or more liqnida. Some are beat preserved in a I 
aolation of chloride of calcium, others in Thwaites' liqaic 
whilst a few keep their colour most perfectly when i: 
glycerine alone. There can be little doubt that light is tli 
bleaching agent in most cases. Many of them, howevon 
are so very transparent that they present bat faint objeoti 
for ordinary observation. For this reason, however, they ai ' 
sometimes dyed in solution of magenta or other colour, b 
elsewhere noticed. The Desmidiacesi require somewhri 
similar treatment, and may be mentioned here. The eolutiov 
of chloride of calcium has been strongly recommended; bat 
no preservative liquid seoms to be without some action npo* 
tbem. Both of the above classes o( objects should bemoantel' 
in shallow cells, so as to allow as high a microscopic powef 
as poHsiblo to be used with tbem. 

Entomostraca. — In every ditch or place where vegetable 
matter exists, these little active, jerkiag pieces of life a 
certain to be found. They are covered with a homy trana- 
parcut shell, and are various in form. Mr. Tatem gives tba. 


following, as the best way of preserviog them: — When 
canght transfer to filtered water in watch-glasseH for twenty- 
foar hours, in order that the contents of the laden inteatina 
may be diacharged, Drair oS the water and add a little 
Bpirit of wine, which qnickly destroys life. Bemove all dirt 
hy aid of a camel-hair peQctl, nod place in a few dropa of 
the medium used and water (half of each] until saturation 
ia complete, and then put np in the medium in shallow onUs. 
The mediom advised is Mr. Farrant'a, which will be found 
amongst thoie recommended. 

Many of the Zoofwjibs which are obtained on onr sea- 
coasts are well preserved by mounting in cells, in the manner 
before mentioned, with Goadby'a £uid, or distilled water 
with one of the additions noticed amongst the preservative 
h'qnida. For eianiination by polarized light, however, they 
are uanally mounted in balsam (se* Chapter IV.), whilst 
those in cells present a more natural appearance as to 
position, Ac., for common stndy. The Polyzoa, also, are 
exquisitely beautiful objects for the microscope, but require 
Home little care. They should be kept iu sea-water until 
their tentacala are expanded, and may then be readily killed 
by plunging in cold fresh water. Thus all their beauty will 
be preserved, and they may be then mounted in one of the 
preseiTative liquids. Many operators speak well of distilled 
■water well shaken with a few drops of creosote, as before 

As to the nue of preaervatire liqnida with the Diatoraaeeffi 
there are various opinions. Some experienced microscopists 
Bay that there .is little or no satisfaction in mounting them 
in this way. Dr. Carpenter, however, explains this differ- 
ence by his instroctions as to what method should be used 
when certain ends are desired. He says : " If they can he 
obtained quite fresh, and it be desired that they should 
exhibit as closely as possible the appearance presented by 
the living plants, they should be put np ia distilled water 
within cement cells ; but if they are not thus mounted within 
a ihort time after they have been gathered, about a sixth 


part of alcoliol should be added to the water. If it be 
desired to exhibit the stipitate forms in their natural para- 
sitism npon other aquatic plants, the entire mass may be 
mounted in Deane's gelatine in a deeper cell; and soch a 
preparation is a very beautiful object for black-ground 
illumination. If, on the other hand, the .minute structure of 
the Qilicions envelopes is the feature to be brought into 
view, the fresh diatoms must be boiled in nitric or hydro- 
chloric acid " (which process is fally described in Chapter 
III.). It is very convenient to have many of these objects 
mounted by two or more of the above methods ; and if they 
are to be studied, this is indispensable. Mr. Hepworth 
once showed me about one hundred slides which he had 
mounted in various ways, for no other purpose than the 
study of the fly's foot. 

My friend, Mr. Rylands, successfully mounts the diatoms 
in the state in which he finds them, and gave me the follow- 
ing method as that which he always employs. He says that 
he has had no failures, and hitherto has found his specimens 
UDchanged. Take a shallow ring cell of asphalt or black 
varnish (which must be at least three weeks old), and on the 
cell, whilst revolving, add a ring of beuzole and gold-size 
mixed in equal proportions. In a minute or two pure 
distilled water is put in the cell until the surface is slightly 
convex. The object having been already floated on to the 
cover (the vessel used for this purpose being an ordinary 
indian-iuk pallet), is now inverted and laid carefully upon 
the water in the cell. By these means the object may be 
laid down without being removed. The superfluous moisture 
must not be ejected by pressure, but a wetted camel-hair 
pencil, the size made in an ordinary qnill, being partially 
dried by drawing through the lips, must be used repeatedly 
to absorb it, which the pencil will draw by capillary 
attraction as it is very slowly turned round. When the 
cover comes in contact with the benzole and gold -size ring, 
there is no longer any fear of the object being removed, and 
a slight pressure with the end of the cedar stick of the 

oe MicBoscoPic OBJECTS. 137 

jteacil will render tba adheBion complete, and cement the 
oover cloaely and firmly to the cell. When dry, an enter 
ring of asphalt nrnkeS the mounting neat and comiilate. 

The Fungi have been before mentioned ; bat it may ba 
here stated that some few of the minnte forms are best pre- 
served in a very shallow cell of liquid. For this purpose 
creosote -water may be advantageously nscd. 

The aTtteiiiiue of insects have been before noticed aa being 
very beantifnl when moonted in balsam. This ia readily 
accomplished when they are large ; but those of the most 
minute insects are mnch more difficult to deal with, and are 
leas liable to injury when put np in floid. Goadhy'e Fluid 
Bsrvea this purpose very well ; but, of course, the object 
most be thoroughly steeped in the liquid before it ia 
mounted, for a longer or shorter time accordiug to the 

The egge of i-nsede afford some worthy objects for the 
microscope, amongst which may be mentioned those of the 
oommon cabbage bntterfliea (small and great), the meadow- 
brown, the pusa-moth, the t^rtoiseahell bntterSy, the bug, 
the cow-dung fly, &,a. These, however, shrivel up on be- 
coming dry, and most, therefore, be preserved in some of 
the flaids before mentioned. To accomplish this no parti- 
cular directions are required j but the soaking in the liqni J 
about to bo employed, &o., moat be attended to as with other 

Glijferino may be advantageoualy used for the preserva- 
tion of various innect?. These should firat be cleaned with 
alcohol to get rid of all extraneous matter, and then, after 
soaking in glycerine, be mounted with it like other objectH. 
There is, however, a dif&cnlty in clearing glycerine from 
the edge of the thin glass aover ; but Mr. Whalley told me 
be met with no annoyance. After laying the cover upon the 
olgect with the glycerine, he took away all the siiperlinoua 
h'qnid with a small piece of lines, cleaning It at kat with a 
damped piece of the same. The small quantity of water 
which gets mingled with the glyceriae doe« no iujury. ' 

xi3 accyr: 

-iii* «rU£mi sa '!« "anH smbdsE TeoBesy €9i:<C£^ fcr uy 
«}>?nj*^': "^i u3ity» JLr Snfiiik. c lae *^^^ii£C3Ci Cmh, wud : 
— '^ina im 'j»iL -wvt nL»e£ its- Taabmoi 2 vEsa. a coating 
uf staLHi'jL liriaf-.ris£. f3i£ v^a. ia5i vbi irx ^ put it 
T2iO!r tJjft 'Un Bif zsisnm^jT -w^iai 2«ix orSsr to icmore 
£ZT r'jKriztt -yiarit iingxi rffnicrr jramS*, Ai^ cvcfbllj 
£1*7 .:i<r t^ iili5» -Ri stbcsaxir-puBr, kie e&ve it another 
Ka::;"!-r it zitt LrrSS-z^iie. im; viis. irj re^«ascd t&e wmsh- 
fxf zyrjts^sm, saii ^ner iiaila g rrreK fs m tbinl coatiiig of 
». vlf-r'xfr =1 tlks aasii^ stuczisr, x« evre is m final eoat of 
gv.i'T^iz^ kZfi x** xriTtr \^ azj tncbSe viih ceDs doeed in 
riLt ZL^r*^. Mr. HBsjc^, ai the lase place^aaid: — EUs 
^v^fi -rsbir, Vjt etx« a ^TA. itsas fv tlie cover fint bj a thick 
Hl;^ "-^f g?=i ^atr^ir — aljov tka to become stidrf ; next 
Y^\ ha iLe g^ronise:, lar on the eorer, and then carefiillj 
wafth o^ an tuperf hogs gljcerine. When perfectlj well- 
wa^h^ axid dried laj on two or three ooats of gnm dammar 
to finish it. 

Some iDiiectf, sncfa as Maj-flies, ^., are, bowerer, often 
j/rtnerred hy immersion in a solotion of one part of chloride 
of caJciam in three or foor parts of water ; bat this has not 
}jeen recommended amongst the preserratiTe liquids, as the 
coloar, which is often an attractive qoalitj of this class of 
objects, is thereby destroyed. 

We have now noticed the treatment which mast be ap- 
I^lied to those objects which are to be preserved in liquids 
and cells. We may here state that all slides of this kind 
should be examined at short intervals, as they will be found 
now and then to require another coating of varnish round 
tlio edge of the thin glass cover to prevent all danger of 
leakage. The use of the air-pump, in the first instance 
(iiH boforo recommended), and this precaution as to the 
varnish, will render the slides less liable to leakage and'air- 
b»bl)los, which so very frequently render them almost 




Majjt objects are almnafc worthleaB to the roicroscopiat tintil 
extraiDeons matter is removed from tliem; and this is fre- 
qaently difficult in the estreme to perform satiafactorily. Aa 
an inatanoe, certain IToraminifera may be raentinned in which 
the cella are placed one upon another, c on iieq neatly the ob- 
ject mnst be reduced to a certain degree of ihimtrss before a 
ingle nniform layer of these cella can be obtained to ahoi^ 
aomethiog of the internal arrangements. 

Mmt animal and vegetable forma require an examination 
of the separate parta before much cafl be known abont them. 
The maaa mnat be divided into separate portiooB, each part 
intended to be preserved being cleaned from the naeleag 
matter with which it is enrrounded. It will freqoently be 
ad neoeaaary to make thin aeotiona, which from a very 
tender substance ia no easy matter ; and much patience will 
ba neeeaaary to attain anything like proficiency. 

This making of aeotiona was not nntil very recently 
nndertaken by many eieept tbose belonging to the medical 
profession, bat I do not aee why this abould be so, aa mnch 
may be accomplished by a pereevering and interested mind 
where there is time for entering into the subject. I will 
therefore make an attempt to give aorae instrnctions on this 
snbject also. We will first conaider the cutting of sections 
a hard substances, in which the ordinary knife, chisel, 


&s., are of no avail. Most of these reqnire no particnlaT 
care in mountiDg, bat are placed in balsam like the other 
objects notiocd in Chapter IV.: where, however, anj Hpeeial 
treatment is necesaary it will be commeoted Dpon aa 

Shells, &c.— lb ia aeldom, if ever, necessary to poBneaa 
apparatua for this process except a email thia saw n 
with a steel blade, for which a piece of watch-apring ae 
verj well ; a Gne stone such aa is ased for sharpening pen- 
knivea ; and two smooth leather Btropa, one of which is ti 
be used with puttj-powder to poliab the section after grind- 
iufli, and the other drj, to give the final surface. It is, how-, 
ever, very convenient to have three or foar files of different 
degrees of Baeneas. A very useful implement in this proceat., 
is the Corondum file or robber, sold by moat dealers in 
watchmakers' tools. It may be procured of almost any tdzQ 
or grain, either circular or flat, and will cut almoat any- 
thing. They poaaeae the very great advantage of not carry- 
ing mnch, if any, impurity into the texture of the object 
upon which they are used. The aholl, if very thick, may be 
divided by using the watch-spring saw; and this sention 
may then with ordinary care be rnbhed down with water on 
the stone until one aide of it ia perfectly flat. When this ii 
accomplished it must be rubbed with putty-powder upon 
the strop, and finally upon the other atrop without Iha i 
powder, This surface will then be finished, and mast be 
firmly united to the slide in the position it is intended to 
occupy. To do this a small quantity of Canada balsam may 
he dropped upon the middle of the slide and heated over 
the lamp until on cooling it becomea hard ; but this mast 
be stopped before it is rendered brittle. Upon thia the 
polished surface must be laid, and sufficient heat applied to 
allow the ohjcDt to fall closely upon the slide, when slight 
pressure may be used to force aside all bubbles, &c. Oa 
cooling, the adherence will be complete enough to allow the 
same grinding and polishing upon the upper surface which 
the lower received. Whilst undergoing thia, the section 

moat be uamioed foiM tine l» tine b ajeeftan ■tirter 
the necMSMT degne of *J'"'— ^ bas leen mebcd. Vbca 
tbia b tbe caje tb« Mctmi iboiiM be waJurt thoRM^Uj sad 
dried. Il moat tboi Iw conred, wbkk ia beat dow by anng 
ordinary Canada babBB, aa TNonncBdfd in Clia]:ter IT,; 
or, if Uie sictkia ia to benoaiited mut be fi«td 6oaa 
bttlaom bj waaHtDg, or ■"—i"'^ if BMeaaarj, in tnrpeatiaa 
or other solveuU. 

Sections of some eiqnjaitelj beantifdl objects are cat with 
tnoeb lees Irooble tban tbe abuTe. Tbe OrbiColite, for 
inBt&ncp, mBj be prepared in this manner. Take the object 
and hj presaure with the Eager rab the iiie apoa a flat and 
BmDoth sharpening Etone *ith water until the portion is 
reached which it Is wished to «bow. The etreo^h of the 
object will easilj allow this to be accomplifbed with ordinarj 
care. This side may then be attached to the glass elide 
with heated LaLaam, as above described, and the object may 
then be genttj nibbed down to the d^ree of thinness re- 
qnired to show it to the beat advantage. After removing 
all disengaged matter from tbe object by washing and 
thoroQghly drying, it may be in>>Dnted in balsam in the 
nanal maiiiit>r, when it is equally beautiful as a transparent 
or opaque objec*. From this it will be seen that in man; 
instances where a smooth stone is fonnd sufficient for the 
wort (which is often the ease when the section is mounted 
in balsam) the Goal process of polishjjig advised above may 
be dispensed with, as in the Orbitolite, Nummnlite, &e., &a. 
It is qoite necessary that the stones on which the objects 
are rubbed be perffcllij fliif-, otheTwise one side must be 
acted upon before the other, and it will he found impos- 
sible to attain anything like nniFormity. Where it is not 
practicable to cut a section, and the object is very thick, a 
coarse stone may be first used to reduce it and the smoother 

The consideration of the cutting of aeetiouB from ahelJs 
would Bcareely be deemed complete without some mention of 
what Dr. Carpenter terms the decalcifying process. Muriatio 

acid is dilated with twenty times its volume of watar, tnJ 
in this tho shell is imniersed. After a period, difieriog ac- 
cording to the ihickoesB of the Ghell, the carbonate of lime 
will be diaaolved away, and a pecaliar membrane left, shoo- 
ing the Btrncture of the tbell very perfectly. This may ta 
mounted dry, in balsam, or eonietimoa in liquid, accDrding 
to the appearance of the object; bat no rule can begiien. 
The discretion of the etadent, however, will enable him lo 
choose the most suitable method. 

Troro some shells it is easy to divide thin ptutee, oi 
lamimu, which require nothing bat moanting in Canads 
LaUam to show the texture very well. In working, however, 
with those which are pearly, it will be found that eipe- 
rienoe and patience are needed, as they are very brittle and 
pecuharly hard ; bat a little practice will overcome these 

Amongst the Echinodermata, which include the Btar- 
fiehea, sea-hedgehogs, &o., there are many whose outer sur- 
face is covered with spines, or thiu projections. Soma 
of these are sharp and thorn-like, others blunt, longer or 
shorter, and, indeed, of endless variety. In many of these, 
when a section is made, rings are seen which have a coo: 
centre, with radiating supports, resembling aectiona of : 
of the woods. These are very beautiful objects, and methods 
of procuring them may now be considered. It la the best 
to cut as thin a section ns can safely be got with %he watch- 
spring saw first, when the smooth sharpening stone may 
be nsed to polish one side, which is easily accomplished with 
water only. When this is effected, it must be washed clean, 
and thoroiigJdy dried, and then may be united to the slide 
in the same manner as before recommended for the Orbito- 
lite, &.C. If it JB ever necessary to displace it on acoouni 
of inequalities, bubbles, or other remediable fault, this may 
be done by warming the slide; though too much heat mnst 
be avoided, othemise fresh bubbles will certainly be pro- 
duced. The covering with thin glass, balsam, &c., will 
present no difficulty to the stadent; but he must remember 

or KJcxofiOH^c omtrn. 143 

[ Aai the transparencj u aomewliat increued hj ihia Lut 

Corals are odea treated in this w»y, in order to rereal 
their atractnre. £ic«pt, bowerer, th« etndeat hu h«d 
mQcb practicf, he will often find Uub a most difficult tAtfc, 
as man; of them are exceedinglj brittle and hard. He wil! 
find the method before described eqaall; applicable lier«, 
and abonld take both horizontal and TerticaJ sectionB. 

Coal. — This enhstance is one of the most intereatiDg 
objects to the microscopist. It is, of course, of veget&ble 
origin i and thoagh it is is rnanj cases in each mioate 
separate portions as to have lost all appearance of v^^ta- 
tion, yet it is very freqnantlj met with in masses, bearing 
the form, even to the minata maikiags, of wood, in Tarioas' 
directions- la see this and prepire it for microEcopio re- 
search, a aaitable piece of coaJ moat be obtaiuecl ; bnt in 
every case the catting and preparation of these sections 
reqaire great care and skill. Sometimes the coal is first 
made smooth on one side, fastened to the glass, redoced to 
the teqaieite degree of tluDnegs, and finished in tha method 
before described. This mode of treating it is sometimes, 
however, very tactalizicg, as. at the last moment, when the 
Bection is ubont thin enoagh, it often breaks up, and so 
renders the trouble beutowed upon it fruitless. The dark 
colonr and opacity of coal render an extraordinary thinness 
neoeHsary, and so increase the liability to this accident. 

Mr. Slade recommends that the piece of coal, having been 
smoothed on one side, be cemented on that aide to a gloss 
slip by marine-glne of the best quality, quite free from 
nndiasolved or foreign matter. Great care mast be taken 
to press out all air-bn'jblea, the coal breaking up at such 
places afl it gets thio, a hole resulting. It may then be 
reduced in the nsual way, and when thin enough mounted 
in Canada balsam and covered by thin glass. 

Perhaps the beat method which can be pursued ia that 
TBEommended in the Jliorographio Dictionary, which it 
as follows ; — " The coal ia macerated for about a week in a 


Bolntion of carbonate of potasli ; at the and of that time i( 
ia possible to cnt tolerably thin alicea with a. razor. Then 
bHcbs are then placed in a watch-glasa with strong nitlifl 
acid, covered, and gently heated ; Ihey ioon turn brownish^ 
then yellow, when the procese mnat l.e arreeted by droppin, 
the whole into a saucer of oold water, else the coal woul 
be dissolved. The slicea thna treated appear of a darkU 
amber colonr, very transparent, and exhibit the atructut^ 
when esiating, most clearly. We have obtained longitndinal 
and transverse eectiona of coniferons wood from varion 
oobIb in thia way. The apecimens are beat preaerved i 
ghjcerine in cells ; we find that spirit renders them opaque^ 
and even Canada balsam has tbe same defect. Sohnltn 
statea that he has brought oat the cellulose reaction witb 
iodine in coBiI treated with nitric acid and c~ ~ 
potaah." Now and then in coal we meet wil 
formed carbon -looking subatance whith is no mc 
to work with than ordinary charcoal. From tliia it ia an 
easy thing to procure iotereatin); slides. 

CawitcWoal :s so close and firm in its strncture aa to be 
much used instead of jet in the manufacture of ornamentaS 
it takes a beautiful polish, and consequently presentfi ths 
atndent with none bat ordinary difficulties in gettiii|^ 
eectioDB of it. Its formation is somewhat different from 
that of coal, sometimea showing tbe transition very clearly 

Fossil TTooi?.— This ia very often brittle and Teqnin 
great care in cutting. There are, however, different kL 
of fossil wood, but to obtain anything like certainty t 
perform much work a lathe ia necessary. I know of 
method bettiT than that given by Mr. Butterworlh, i 
shall therefore make use of hia worda. First, I will brgj 
with the cutting. To the framework of an ordinary fi 
lathe I attach an upright epindle (see engraving), 
upright apindle I drive by a band passing over 
pulleys " from the wheel below. On the top of this w_ 
I fii my outting-diac, which ia made from a veij 1 
piece of sheet iron, and ia about sii inches in 

T I etarge with diamond -powder. To 

T I hold my Hpecimon, and aa it oats I 

amali brosli dipped in turpentine. 

"With this method I have ont aectiona of foaail wood bo thin 
that all ita atrocture haa been well defined and required 
nothing hnt mounting in balsam; thia baa been gilicnted 
foaail wood. In cntting calcareous fossil wood, I have to 
cnt the aectiooa thicker and grind them down. My grinding 
apparatus is composed of leaden laps, whieh I make to 
revolve in a horizontal position on the same upright spindla 

1%i •»T3r»tT»^naff jsa> aflLAgac 

Ta 'w^cuGL Z iz TCT sar.r.ring wmw. I lae tvo lafa» one for 
rtngi j— "Vii^rrry^ t^ic- ^ipfflT &r flBocckzaf. I vae 2^ot. 1. 
eixisj sai£ & zzLJit wsSBT wiSk tfe £alu and floor of emery 
«x& 'uExrrr ^ -v'issr hl liie mecmi^ !■ pvcfAiiiig a qteci- 
moL, I fr« £75Eiif & sxcGcck irfMf on oae aide, and then 
£z fs ^^ a poiSe ^ siiSaaSy of lock a sae as will suit mj 
ipggrenrgg . ^rm Caai^3a bahM, I then redoee it in IhidnieBS 
OL tkji TznA lap t2! I bcein to see tlie liglit tliroogh it. 
T^«B. I he^s, wish the tmtxdiang lafs and redoee it with 
Sfjrar c€ CBeej vorul evaj pait of its stmcliire is distinct. 
If I fhfiom to pofidk the qwdmen I do so on a lap made 
c^ plnth doth or eoSton Tcvet and potty-powder. I then 
fi^Mt them off the dide on wlndi they bsTe been gronnd, 
and £x them on another with Canadla balsam. I prefer, 
wb<Te it is pia^cticaljle, to moant them in balsam nnder a 
tbin eorer in the nsoal way, as I am satisfied that the 
stmctnre is better brought oot. 

In JlirU there are often found remains of sponges, shell?, 
"D'tAUimzcesd, &c, ; bat to show these well, sections mnst be 
cat aild polished by the lathe and wheel of the lapidary, 
which the microscopic student seldom possesses. Thin chip- 
pings may, howerer, be made, which when steeped in turpen- 
tine and monnted in balsam, will frequently show these 
remains very well. 

Teeth are very interesting objects to all microscopists, 
more especially to those who give much study to them ; as 
the class of animal may very frequently be known from one 
solitary remaining tooth. To examine them thoroughly, it 
in necessary to cut sections of them ; but this is rather diffi- 
cult to perform well, and needs some experience. Some 
inNtruotions, however, will at least lessen* these difficulties, 
itnd wo will now endeavour to give them. 

B notions of teeth and bone may be successfully made by 
rubbing ulicos out with a saw between two plates of ground 
glnNH, with wntor and a little powdered pumice-stone, the 
oM ntul partially worn glass being kept for the final 
polishing of tho aeotions. 

or Miciostoric cutca. 117 

Tt ia genersHj Uwogbt that Canadk VW™ iBJnre* the 

Ener raarbiogs of tbcae aMttoaa, eoiisttjneatlj. they aim 
almost, invariablj nramited dry. A this piece ia Srat cnt 
from the tooth with the aaw of wktch-vpriag bc£:Te 
meottoned, if possible; bat ihciDU the solatajKe be too 
hard for thiE, the wheel and Iath« most be nted with 
diamond dast. If chia cannot be procnred, there ts bo 
alternative bat to rnb down the whole Eahstance as thin as 
practicable on some coarse stone or file, or best of all th» 
corondam robber. The snrfai^ vill then be ivngh ; bat 
this may be much redaced by mbbTOg apon a flat abarp- 
eniDg atone with the finger, or a Email piece of gntta-percba 
npon the object to keep it in contact. The scratches may 
be mnch lessened by tbis, hut not so thoroughly removed as 
microscopic eiaminalion requires in dry sections. It most, 
therefore, be polished with the pntty-potrder and dry strop, 
aa recommended in the working of shell -sections. The 
other side of the section of the tooth may then be mbbed 
down to the reqaisite thianesa, and polii^bed in the same 
manner, when the dnst and other impartties mnst be re- 
moved bj washing, afler which the section must be carefnlly 
dried and mounted. Som.etimeB it may be deemed desirable 
to make a preparation of the teeth in situ ; for this pnrpo?e 
tate the lomer jaw of some animal like the rat, weasel, or 
gninea-pigi and soak it in absolute alcohol first, let that evapo- 
rate oat, then soak in the aolution of balaam and benzole ; 
when that has evaporated to hard neas, grind down the jaw as 
a section, the teeth are fiied in by the baleam. Some of 
these sections are equally interesting aa opaque or trans- 
parent objects. 

The dentioe of the teeth may be decalcified by immeraion 
of the section in dilute muriatic acid; after drying and mount- 
ing in Canada balsam it presents a new and interenting 
appearance, showing the enamel fibres very bcauliFully 
when magnified about three hundred diameters. A friend 
tells me that after snjjmoraion of the whole tooth in the acid 
ho has been able to cut aeotiona with a razor. 

Sbciioks of Bone. — With the aid of tlie microscope few 
fragmeDtary renmiDB have proved bo DEeful to llie geologis 
and Btudents of the foBsil kingdom a.8 these. Fro. 
epeoimen many of our naturaliata can teli with certaintj U 
irhat class of animal it baa once belonged. To 
tbia point of knonledge much atudj ia necessary, and sectiona 
of Tarioua kinda ahoul J be cut in Huch a manner as nill beat* 
exhibit the peouliiiritiea of formation. The methods i 
accomplishing this will now be conaidered. It may, h 
ever, he first mentioned that the chippings of some boneC 
will be foasd Dseful aow and then, aa before stated t 
flint, thongh this is by no meana a satisfactory way of pro 
ceeding. Sometimea the banes may be procured natnrally n 
thin that they maybe examined without any cutting; and ontjF 
require mounting dry, or in fiuid, as may he found the besfi 

When commeucing operations we must provide the a 
apparatus aa ia needed in. cutting sections of teeth, befoti 
described. A fine saw, like those used for cntting braa^ 
&c., two or three fiat filea of difierent degrees of coaraem 
two fiat " aharpeniag " stones i aud a leather strop t 
pnttj-powder for polialiing. As tbin a section aa poasibli 
should first be out from the part required by the aid of thi 
fine saw ; and it is better when in this state to aoalc it foi 
Bome short time in carophine, ether, or some other spirit t( 
free it from all greaie. With the aid of a file we may no« 
reduce it almost to the necoasary degree of thinnes 
proceed aa before recommended with teeth. The " sharpeii<i 
ing " stone will remove all acratchea aud marks suffioientl) 
to allow it to be examined with the microacope to see 
ground thin enough ; and if it ia to be mounted dry w 
polish it with putty-powder and water upon the strop to H 
high a degree aa possible, and having washed all remain 
polishing powder, &c., from the aection we must ploc 
npon the slide and finish it as described in Chapter 
But where these sectiona are reqaircd for mounting i 
balsam a less amount of ]ioJiKli is necessary ; thus rendering 
the whole prooeas much more readily completed. 


Xf the bone is not safSciently hard in ita nutare to bear 
the above method of handling whilst grinding and potishing 
— SB some are far more brittle than others — oa thin a sectbu 
aa possible mnst first be cut with the saw, and one surface 
groond and polished. The piece mnst then be driud and 
united to the glass bj heated halsam io the same matmrr 
shelU, &c. After which the superabundaQce of balaum 
mnst he removed from the glasB; then rub down upon the etona 
and strop bh before, Gi'eat care must bo taken that the oaoala 
be not filled dnring the process with the dnat of the bone, 
r of the polishing material. Dr. Beale, in the jonrnal of 
the Q. M. C. takes occasion to say " that he cannot admit 
that the best way of preparing such sections is by grinding 
' ia too liable to fill the canals wilh di^hi'ie." Hu 
reeommendB that a fresh bone he taken — and a aniall slice 
off by a strong sharp knife. Thi* is then to be ini- 
mersed in. carmine diaaolred in ammonia — the ammonia 
being first nentralized by acetic acid. The wal'.s of the 
Teasels ivhich penetrate the lticiiu(B and canalictiU are by 
this means stained crimson, and thus the trae sttuctnre of 
bone is rendered viaible. When the polishing ie completed 
whole slide must be immersed in cblorotorm, ether, or 
e other spirit, to release and cleanse the section, wheu 
it may be monnted as the one above mentioned. 

lome bare recommended a. strong solution of iainglaaa to 
e: the hiilf-ground teeth or bones to the gkas as causing 
ra to adhere very firmly and requiring no heat, and also 
being readily detached when finished. 

The reason why the sectiona of bone are nanally mounted 
dry is that the lacimis, bone cflls, and canalicuU (re- 
sembling minute canals) show their forma, &c., very per- 
fectly in this state, aa they are hollow and contain air, 
whereas if they become filled with liqnid or balsam- — -which 
does sometimes occnr — they become almost indiatingoiahable. 
There are some dark specimen?, howevor, where the cells are 
already filled wilh other matter, and it ia well to mount these 
with balsam and so gain a greater degree of transpareDcy. 


To obtain a true knowleUge of the *trnotnre of b 
secUooB ina:(t be cut as in wooi], botb tranaver^ly and' 
longitudiaallj ; bat vith fos/il bones, without the lapidary's 
wheel, it is a laborioas, and incleed can seldom be 
properly accomplished. In this place, alao, it may be 
mentioned that by submitting bone to the action of mnriatic^ 
acid dilated tea or fifteen times nith water, the lime, &c., 
diaflolved awaj and the cartilaj^e ie left, which may be cot 
into sections : la camtic polasli the animal matter i 
rid of. Both of these preparations may be mounted ii' 

The tncthod of cutting thin sectjous of bone may be t 
employed with the stonea of fruit, vegetable ivory, and si 
like Bubstancea ; many of nhiuh show a moat interesting 
arrangement of cells, especially when the sections are trans- 
verse. Most of these objects present a different appearand 
when mounted di-ij to that whioh they bear when in dalsani,: 
owing to the cells becoming filled ; and to arrive at a. tm^ 
bnonledge of them we mnat lia<re a specimen mounted iet 
both ways. 

Some will perhapg remark that moat of the directions for 
section cntting are giren to those who are totally without 
artificial power, and must rely upon 
tioQs. I reply that these hiuta are 
bat Mr. Butter worth's directions t 
ample, that a repetition of them at the i 
of " sectiooal " substance would be n 

To those who study polarised light, few objects 
beautiful than sections of the different kinds of horn. 
will brieily inquire into the best method of cutting t 
There are three kinds of horn, the first of which is bard,' 
as the stag's, and must be cut in the same manner as boaft. 
The second is somewhat softer, as the cow's. The third id 
another and still softer formation, as the " horn " (as 
termed) of the rhinoceros. In cutting secttoaa of the tira 
e should succeed best by using the machine iDveDtedi 
for these purposes, which I aliall shortly describe when t' 

wu manual exelw 

ostly given to 
) the lathe are so 
intion of each cl 

e tautology. 

or loCBOsconc osjects. Icll 

I Bsthod of cutting wot-i u coQBiderei]. To aii nj in iiaa 
D the horn is hard it mast be boiled far a. shorl time in 
water, after wLicli the cutting will be more e&^ilj affect«d. 
The BectiuDS sboaiil be b<jt!i truuTerw and longitadinaJ, 
tliOBe of the former often ehowing cell* with beantifnl eroEses, 
the coloars with the selenite plate being tmlj splendiil. Of 
this class the Thiaoeeros horn ia one of the hast; bat the 
bnSalo oIeo aSbrds a rerj handsoiiie object. The coir'tL, and 
indeed almoKt esery diifcrent kind of horn, welldeserreB the 
trouble of mounting. Whalebone, when cut tTansTer»elj-, 
strongly resembleH those of the third and soFler formation. 
A!) these are best Been when mounted in Canada babam, 
. but care must be taken that thej have been thoroughlj dried 
after catting, and then steeped in turpentine. 

An ioteresting object maj cIm be procured from whale- 
bone bj cnttiug long EectioDS of the baiiG of vhich it is 
composed. Dona the centre of each hair we shall £ad a 
line of cellB divided from one another very dintinctly. And 
(a§ recommeaded ia the Micrograph ic Dictionary) if 
whalebone be macerated twenty-four hoars in a solation of 
canstic potaeh it will be so^ned, and by afterwards digest- 
ing in water, the outer part will be resolved into nameroaa 
transparent cells, which will show more plainly the stracture 
of this curioaa sabstance. 

An object nlijch frequently comes to the band of any 
man who moves aboot in the world is a porcupine quill. 
Thia ia a really valuable object for the micrOoCupist. Trans- 
verse and longitudinal eections possess their respective 
beaaty; and their appearaace varies somewhat as to the 
distance from the poiat at which the section is made. 
Soaking in hot water for a short time renders it easy enough 
to cut, and when dry and mounted in baJaam the student is 
well repaid. 

In a former chapter, hairs were mentioned, their many 
and interesting forma, and their beauty when nsed with 
polarised light. The sections of tlieni, however, are no less 
a matter of study, as this mode of treatment opens to sight 

i"* " ■ ' ■ - - - 

•eitna «i«qHBi,iMK ffan ■ ^tmm&j ot ham batwiit 
tMiit|Matf M^vUcfc hf f «MM» hJa thf finnly 

c*M^ lofalker to ■■•« tke wq wiwd poitioBa to bo cut 
«tt ft file. O&cn take m immik of the bain and d^ 
it ado gvs or ^m^ ahich gRMit wbatdijftBoliditjcqa^ 
towooA. Beetwaaf tkk an Oca cat with tfae ma^iM 
■Mlioirf a EUIe ftrtkcr <n, aad tkeae maj be loomnted In 
balwM. TIm &■■«■ bair ia eanlj proened in tbe dedndl 
aectiaaabT diavugaa doarlj a* poanble a second timeuj' 
dcanang from tlia lalli^, te^ bj carefallj washing. Moit > 
bain, howerer, abonld be eiamined botb transTeTsely and 
loDgttiidinallj. It ie not diScalt to procnrc the latter, aa 
we majr generallj tplit them with the aid of a sharp razor. 
In a great namber of hairs there is a quantity of greaBf 
matter which most be removed hj soaking in ether or some 
other Bol*ent before moDDtini;. 

We may neit consider the beat method of procnring 
Hctions of wood, which most be cut of each a degree of 
thinneas as to form transparent oT^jecti', and eo display all 
the secreta of their structure. There is no monotony ia 
this Btody, UB the forma are so various, and the arrange- 
ment of the cells and woody fibre so diSerent, that the 
microscopJBt may find endless amaaement or atady in it. 
From a ainglo Bcstion the claes of trees to which it baa 
belonged may bo known, often even when the wood iafoeiil. 
Tho apparatus best adapted for entting these aectiona ia 
made aa followa ; — A flat piece of hard wood, abont eiz 
indies long, four wide, and one thict, is ohoBen, to which 
another of the same siKe is firmly fixed, so as to form, in 
u eidu view, the letter J. On one end of the npper aurfaca 
is fWatened a brass plate, perfectly flat, in the centre of which 
u circular opening ta out about half an inch in diameter. 

■bofe tW Mi&M of tke hcHi pWc H^ MW koil ^ « 

ly BOOB c£ tha InOoa aoMr Moti" 

iiiiiilaiil liiililiii I'l ■ I wiMii Aa'totkcQ 

of wbidb otj ecti AnaH ha ea^ ao foper dptliuMi cmb ba 
giren, m tliia difioa ao pc^^ Aat H)tU^ list BqwrinMa 
can be kof goide. na MiMa ttodmaa caa be oUuaed by 
woiting tlie Kttw Badenoitk uaufara degna, tbe bead 
bong marked fbr Uub pnrpaaai aad wkacllwsdfaalkBee to 
be ent ia ver^ mBch smalla' thaa tbebola in the bnas plate, 
it may be «edged witli corfc. 

*Am this instrnmeiit U peeoUarij adapted for cattutg 
wood (thoQgh D5ed for other eabstanMS, as before men- 
tioned), I Hball notice a few particolan coDcerning tbis 
branch of SM:tioii8. It may here be remarted, that to 
obtain asything iike a true knowledge of the natore of 
wood, it should be cot and examined in at least two direc- 
tions, across and alon-j. The piece of nood ia often ptoceU 
n spirita for a day or two, so that ail lesinoua matter may 
be diaaolved oat of it ; it moat then be soaked in water for 

M. Mouohet, ia ordor to avoid all danger of "bennia" in oiitting 

d smitioin, procured a knife wilh a. seniicimulsr l..lodB, Thii WM 

«..ui n. fh^ ^...1 nr.™ „ Hat |)late, in ordor to revolve, lU v- ■"'■" 

1 ._ .j^g loTorogo fiirftiiyi 

can it, tbe han<Ile being long en! 

rer. The wood supporter bci^ ^'"■"■'•^ '" » '•' 
knife is esail 7 brougbt round, and tlie seotiuu 

it tiy a strculitr 

lul rnEriHATioN and mounting 

tbe same length of time, so aa to eoftea aod render it esLtf 
to cat. Sections mtij tben be oLbaiaed in the manner juBt 
described, but they often curl to auch a degree from thei« 
previooa immersioti ia water aa to render pressure necesBBj^ 
to flatten them until dry, Tbej are often mouoted dry, 
and require no care beyond other objects, as in. Chaptei 
III. Home, however, ara best mounted in bah 
ticolarly the long sections when used for the polariscope^ 
these must he soaked in turpentine, and the greatest c: 
taben that all air-hiibbles are removed. Others are thoughb 
to be most useful when moantcd in shallow cells with bi 
the jire^eryad'ufl liquiiU mentioned in Chapter V.- 
Bpirit and water, chloride of calcium solution of the etrengtll 
of one part of the salt to three parts of distilled water, &e,. 

The above " BedloTi-cutteT " may not be within the ti 
of every student, nor is it absolutely necessary ; though where 
any great nujiiher of specimens is required it is very use' ' 
and insnres greater uniformity in the thickness, Manj 
employ a razor for the purpose, which must always be iepi 
sharp by frequent stropping. Sections of leaves also maj 
bo procured by the same means, though, as before mentianedi 
they are BOmetimes divided by stripping the coatings o^ 
with the fJQgera. The cells which come to sight by cutting 
some of the orchideous plants are most inteieBting. Tocal 
these leaves they may be laid upon a fiat piece of cort, thni 
eiposing the razor to no danger of injury by coming in 
contact with the BOpport. It may be mentioned here that 
the ra^or may also be used in cutting seotiouB of the r 
than which a more beautiful object can scarcely be found 
when viewed transversely, as lb shows the stellate arrange- 
ments of the parenchyma. This should be mounted irjii 
In the same way sections of the leaf-stalks of ferns may also 
be cut, Bome of which, as Dr. Carpenter states, show the 
curious ducts very beautifully, especially when, cnt rather 

It has been found a ready method of catting sectione oj 
the rueh and such like plants, to suck n, solution of gam nj^ 



• into the pitb, and when ttis is dry thia seoLioua oonid Le 
ont and the gum waahed out again, and lliese could ba 
mounted in balsam. 

The plan adopted by moat practical histologiBta for cut- 
ting aections of soft tiaaoea ia aa followa : — The tissue to ba 
cat is lirat hardened bj immersion in a chromic acid boIu- 
tion varying in strength from 0"25 to 2 per cent., or by im- 
mersion in alcohol. The subatance to bo cat may then be 
embedded in melted wax and Bpermaceti, ia proportions 
suitable to the nature of the substance to be out; when 
this is cold the section may be cut with a razor ground 
flat on one side, and may then be floated off in spirits of 

These sections mount very well in Canada balaani, if 
after being removed from the spirit they are immersed in 
oil of cloves till they become ulear, then put into turpentine 
before the balsam. The thinneas of the section will depend 
very much on the deiterity of the operator, but section- 
cutting iostraments for soft tissues cau now be obtained at 
most scientific instrnment shops. 

When sections of softer aubstanoea are required, no instrn- 
ment can be compared with " Valentin's knife," which con- 
sists of two steel blades lying parallel with each other and 
attached at the loner end. The distance of separation may 
be regnlated at will by a small screw near the handle. 
When, therefore, a section is wanted, the substance must 
« cat through, and betwixt the blades a thin strip will be 
foand, which may be made of uoy thickness, according to 
the distance of their separation. By loosening the screw 
the blades may be extended, and the section may be floated 
OQb in water if the damp wilt not injure it. The knife cats 
mnch better if dipped in water or glycerine immediately be- 
use, and also when the substance to bo operated npon 
is wet, or even nnder water altogether; but care muat be 
taken, after use, to clean the bladoa thoroughly and oil them 
ire laying by, if the place is at all damp. This instru- 
ment is most Dseful in such aubjects as anatomical prcpara- 

t!ona where the sections are required to ahow the position d 
the dilferect veaeels. &c. ; bat, aa before stated, ia very tah- 
able for all soft sabstuDcea. As an instance of tlik, it may 
be mentioned, that it is frequently naed iu catting BBctions 
of spoDgea ; but BB theae aie oftea very full of apicaki 
it is much better to preee the »pooge flat nntil dry, and than 
oat off thin efaavings with a very sharp knife; these stiavii 
ioga will eipand when placed in water. After this thay 
may be laid betirixt two Sat enrfacea and dried, when they 
may be mounted as other dry objects, or, when dtisirable,u 

Valentin'a knife ia very mnch need in taking aections 
skin, which are afterwarda treated with potash solution 
Bcida, &a,, to bring ont in the beat way the different por 
tioDS. Dr. Lister's mode, however, of getting- these ia tbu 
given in the Microscopic Journal ; — " Bat I afterward 
fonnd that mucK better acctiena conld be obtained froE 
dried apecimena, A portion of shaved aealp being place 
between two thin slipa of deal, a piece of string is tie 
round tbem so as to eseroise a slight degree of oompreBsioa 
the preparation is now laid aside for twenty-four honi 
when it is foand to be dried to an aJmoet horny conditio 
It then adheres firmly by its lower surface to one of tl 
slips, and thua it can be held aecurely, while extremely thi 
and equable sectiona are cut wilh great facility in any plai 
that may be desired. The^e sections, when moistened wit 
a drop of water aud treated with acetic acid, are as w< 
suited for the investigation of the muscular tissae aa if thi 
had not been dried." 

There are many who almost confine their attention < 
polarized light and ita beaulifnl efiecta. Such would ni 
deem theae efibrta to aid the etndent in cutting si'ClioD 
complete, without some notice of those which are take 
from various crystals, in order to display that cm' 
beautiful phenomenon, the rings \eilh a cross. The 
roent of these is somewhat changed by tbe crystal w! 
affords the section ; bat nitrate of potash gives two seta 

OF wcsoscopic OBJECTS. 157 

TingB with a cross, the long line of which posses tirongh 
hoth, the short line dividing it in the middle. 

The process of catting theae Beetiona is rather difficolt, 
it a little care and perseverance will conqner all this. The 
following is extracted from the Encijelop<Edia MetTopolitana : 
" !Nitre crystallizes in long sii-sided prisms whose tectioa, 
perpendicalar to their sides, is the regular hexagon. They 
are generally very tonch iotermpted in their strnctnre; hnt 
bj turning over a consideralile quantity of the ordinarj 
saltpetre* of the shops specimena are readily found which 
have perfectly transparent portions of some extent. Select- 

ine of these, cot it with a tnlfe into a plate above a 
quarter of an inch thick, directly serosa the ajis of the 

a, and then grind it down on a broad wet Sle till tt 
is reduced to abont one quarter or a sixth of an inch tbick, 
smooth the anrface on a wet piece of emeried glass, and 
polish on a piece of silk strained very tight over a strip of 
plate-glass, and rnbbed with a mixture of tallow and colco- 
thar of vitriol. This operation requires practice. It cannot 
be effected unless the nitre be applied wet and rubbed till 
quite dry, increasing the rapidity of the friction as tJie 
moisture evaporat-es. It must be performed in gloves, as 
the vapour from the fingers, as well as the slighteat breath, 
dims the polished sarface efiectually. With these precau- 
tiona a perfact vitreoas polish is easily obtained. We may 
here remark, that hardly any t^vo salts can be polished by 
the same process. Thus, Bocbelle salt mnst be finished wet 
the silk, and instantly transferred to soft bibnloua linen 
and rapidly rubbed dry. Esperjenoe alone can teach these 
peculiarities, and it is necessary to resort to contrivances 
(sometimes very strange ones) for the purpose of obtaining 
good polished sections of soft crystals, especially of those 
easily soluble in water. 

Sometimaa tlie saltpetre of the shops is nitrate of mila, and as 

is sligbtlr deliqnoaconc, it ia wal! to be cortaia that ire have the 

nitrate of jjaliuA, wliiuli ia free from thi^ defect. 

0w -li-ti'' «tir wfl,— M Intud 9v. 1 "' 
nfl^ i^ v^ ooM-, l«t Oe irntiillj a 
|iii¥iliiiji, tbewM alwMl too grcst br tks 
■Mt be left to tb ^fiimrj. Tiam tmnamm 
hovefcr. v«f W MM hj MBg k pbto of iea 

TTiT ■«1«ilin,lh<w iiHii 

tiaa a fes' JtScahiw «Ud way b» met 
ifBtdie^ Tbe tawmot rf tbcM k tbe 
olJMt^ vkidi haye Mit rcMtaaea OMOgli in tliciBBdrai I 
bnr cntttng eren witEt the sbnport inatminenis. Thia 
often be remored bj antkiiig in » Botutioii of gnin, and 
3rjiDg, wbieh wilt render the sabBtanee firm enoagh to be 
cut, vhen the teetiaag mn^t be steeped in water, and the 
gum tbna removed. Small seeds, £&, maj be placed 
wfti wbeQ warmed, and will be held Srmlj enougli when it 
JH again cold to allow of them being cot into seclionB." 
And, laetlf, where a eabstitnte for a micrOHCopist's hand* 
Tice ii rfqoired, a cork wbicb fits anj tabe large enoogll' 
may be taken and split, the object being then placed between 
the two parts, and the cork thnist into the tabe, a sufficient 
degree of firmness will be obtained to reaist anj neceBaatJf 

• Mr. T. K, Parker informs mo tl 

t'Bot-tnpport" when aeotionaare required, as follows :— ^"The miiturtf 
use (or embBcldiDg objeots coDSists oreolld piiraffine (aidinar; pant- 
'.o rery well) melted down and mined with » litfla 

parafflDo oil, withoi 
The mixture when 
nut In the centre, t 
mcltad mixture pou 

which the 

hard to be easily onfc.-' 
._. _ _ siiitsble pieces, a hole a Boooped 
to be cut placed in it, and a. little of tiM 
miiLuru iiuuruu luuiid it. The seotiuos are cut with aa Dnjt> 
SOT, which, OH well lu the object, must be continuallv wetted 
irit. This method is iiaoful for all objects which are either tM 
ir tho bund or too aoft or brittle to be cut in the ordinary way. 
ipedallj ueeful for biitologiaal specimeDB, leiiTes, embryo^ 

or lEicBOscopio OBJECTS. 159 

The ether process of drying tiesuea has been described by 
Mr, Suffolk, at a meeting of the QueVett Microscopical 
Clab, and waa communicated by Mr. Crooter to hitn— it ia 
as follows : — A wide-montbed well-stoppered bottle muat be 
selected. At the bottom is placed a slice from the bowl of 
a tobacco -pijje, forming a support for a Berlin crucible with 
its oovor. A quantity of fused chloride of calcium in frag- 
ments ia placed at the bottom of the bottle, which ia nearly 
filled with pure ether, so that the orncibla may he covered. 
The tissue to be dried is planed in the crucible, end is covered, 
if necessary to keep it from floating, by a piece of glass. 
The ether takes water from the tisane, and the chloride 
again takes it from the ether; ao that the section ia thus 
gradually dried, and with aa little shrinking aa possible, 
however delicate it may be. This process ia moat fitted for 
the preparation of sacculent roots, tabers, or utema, and in- 
deed ia only fit for those tissues which are not injured by 
immersion in ether, or dissolved by it, such as fat, &a,, or 
colouring matter. 

DissBcnoN. — As I atated at the commencement of thia 
chapter, no written inatrnctions can enable any student to 
become an adept in this branch without ranch esperience 
and no little atody. I will, however, describe the necessary 
apparatus, and alterwards mention the mode of treatment 
which certain objects require. 

A different microscope is manufactured for the purpose 
of dissection, most first-rate makers having their own model. 
The object-glaaaea of many of these are simple, and conse- 
quently not expensive ; bnt one of the great requisites is a 
etage large enough to hold the trough, in which the opera- 
tion ia otten performed. "Where thia ia the case it would 
scarcely be worth the expense of getting a dissecting micro- 
scope if the student were pursuing no particular study, 
but merely nsed the instrument when an object to be 
operated upon turned up accidentally. The ordinary form 
ia much improved for this purpose, by having two wooden 
rests placed at the sides of the microscope, upon which the 


hands may be supported wben working npon the aUge, 
Thej should be n'eightj- enough to be free from danger of. 

moving. These snpports nil! alao he found to remedy 
mach of the weariaesB nhich inentabljr arises from baTiog- 

to BOBtala the hands as well aj work with them. The 
erector, as I before observed, is necessary to a yoang stadent; 
but with a little practice he may work very well withont it, 

We will now notice some of the instruments which ars 
moat useful in dissection. Tno or three different sii 
ordinary scissors should be possessed, but the shapes must 
be as modified in others for many pnrposes, as those used by 
Burgeons; a pair with the cutting parts hent in a horii 
zontal direction, and another pair slightly curved in I 
perpendicular ; so that parts of the substance operated upon 
may be reached, which it would he impossible to tooch with 
straight scissors. One point of these is sometimes bli 
and the other acute, being thus made very useful in cpei 
tabular furmations. Another forni of these is made, whera 
the blades of the scissors are hept open by a spring, the 
handles being pressed together by the fingers. Where ' 
desirable, one or both of these handles may he lengthened to 
any degree by the addition of bdibU pieces of wood. 

The Enu'es which are most nseful are those of the 
Bmallest kind which surgeons employ in very delicate opera- 
tions. These are made about the length of an ordinary 
pen-knife, and are fixed in rather long flattiah handles; 
some are curved inwards, like the blade of a scythe, othen 
backwards ; some taper to a point, whilst others again 
broad and very much rounded. Complete boxes 
now fitted up by the cutlers, of excellent quality and 
prisingly chfeap. 

Needles.^ — These are very nsefal and should be firmly 
fixed in handles as recommeoded in Chapter II. It is con< 
venient to have theia of various lengths and thicknesses. If 
curved by beating and bending to any required shape they 
may bo re-hardened by putting them whilst hot into cold 
water. Dr, Carpenter also makes edged instruments by 


rtibbiDg down DeedleB upon a hone. They are more pleasant 
to work with vihea $liorl, a,a tlie spring thoy iiave wliilst 
, long robs them of mnch of their firmneBS, Glaee pointa 
nutde by draning oat gIa°B rods to & point will be found 
QSefnl in manipalating with acids. 

A glass syringe is also nsefol in many operationa, serving 
liot only to cleanse the objects but to add to, or withdraw 
liquids from, the disseding-trough. This trough will now be 
deBcribed, as many aahstaucea are so changed hy becoming 
dry that it is impossible to dissect them nnless they are 
immersed in water daring the operation. If the object be 
opaque and must be worked bj reflected light, a small sqnare 
trough may he made to the required size, of gutta-percha, 
which substance will not injure the edge of the kniTea, &c. ; 
bnt where transparency is necessEirj, a piece of thin plate- 
glass must be taken, and bj the aid of mariue-glue (as 
explained la Chapter Y.) sides affixed of the required 
depth. As pins, &o., cannot be iised with the gUas troughs 
and the substance must be kept extended, a thin sheet of 
eork loaded with lead in order to keep it under water may 
te used ; bnt this, of course, renders the bottom opaque. 
When working with many thin substances, a plate of glasa 
three or four inches long and two wide will serve every 
purpose, and be more pleasant to use than the trough. A 
drop or two of water will be as much liquid as is needed, 
Kod this will lie very well upon the flat sorface. An these 
' are the principal apparatus and arrangements which are 
requisite in dissection, the method of proceeding in. a fen 
cases may now be noticed. 

Vegetables. — The dissection of vegetable matter is much 
less complicated than that of animal ; maceration in water 
beiog a great assistant, and in many cases removing all 
necessity for the nee of the knife, especially if hot water can. 
be used without injary to the objects, as is the case with 
many. This maceration may be assisted by needles, and 
portions of the matter which are not required may be re- 
moved by them. When, for inatance, the spiral vessel^.- 

—Iter w^ fa iwBiui bvm ffa qiinl TeMda,^u(li 

B nji«t Am* to a deaa ri^ of giua, npe«Uiig Um p 
I avi at iMt waaUsf well, geed ipMuacBS naj fa pn 
} >MtiirtfawifavldfaBwntcduBO«eoftke|>TeK 
lifBidi m tfa Bwwr dMcritud in Cfapter T. 
fa ww u, B^ fa dried <m ike ifidc^ imm«r»ed id tnrpentin 
■■d tfaa BOOBtcd tB fafaai ; Int liquid ia prel«raUe, eu ' 
fact ynmg wt M that natwal sppesiaaw. Certain kinda 
I •(ft.tsUei reqnre a different Ufatnent to separate tlic 
'nlTMBciU. Aapu«giiaiBCOii^)oaedof Tei7 bard vegetaU 
Iter, and aame have reeommendcd the stems to be fir 
I failfd, wladi will soften Uiem to such a degree that tbi 
I naj eaailj be Kpaiated. Dilate acids are also occaiioDBJl 
t Bsed to effect this ; and in eorae iastancps to obtain f 
rapkidtt caustic pota«h ma; be emplojed ; but after any 
these agents have been osed, tlie objecta mast be tboronghl 
cleansed with water, else the dissecting icatmaents (i 
perhaps the cell) will be injured bj the action of the 
mainicg portion of the softeaing agent. 

For the dissection of animal tisiues it is necessary that 
the instrnmentfl be in the best order as to sharpnea. 
and as the rales to be observed mnst necessarily be sotac* 
what alike in manj instances, the treatment required bj 
some of the objects most freqaently moonted will now ' 
deacribed. We may here remark that cartilage can 
best examined by taking sections which will show the al 
rangement of the ceils very perfectly. This, however, 
plainly seen in the monse's ear without any section being 
necPHsary. Glycerine, the preservative liquids before raea« 
tioned, and Canada ba,lBam are all oied to moant it 


bnt pertflpa the firet-named maj be preferred in many 

Before treating of separate objectn it will be well to notice 
wlftt M. Brnnetti has eatd on preparing anatomical speci- 
mem. The proceea oonsiats of four atageB— viz,, waahiog, 
divestiiig of fat, treating witk tannin, and deaiccatloii. A 
Btream of pure water is injected through the blood-veaselB 
and secretory ducts of the part to he preserved ; the water 
is afterwarda espelled by meane of alcohol. To remove the 
fat, the vessels are in like manner injected with ether, 
which penetrates the tissnes and dissolvcB all the fatty 
matters. These operations occapy abont two Loara, and 
the object thns prepared may then be kept for a long time 
in ether, if desired. A solution of tannin is next injected 
in a aimilar manner, and the ether washed ont by a stream 
of pnre water. The preparation is then placed in a donble- 
bottomed veaael containiog boiling water — a sort of lain,- 
marie — in order to displace the floid previously naed by 
dry heated air. Air compressed in a reservoir to about 
two atmospheres is forced into the vessels and ducts 
through heated tubes containing chloride of caloinm : all 
moisture is thus expelled and the process ia completed. 
The preparation thus treated is light, and retains 
its volnme, iis normal consistence, and all ita histological 

Muscle. — This ia what ia commonly called the fleah 
of aoiaiala. If a piece be laid upon the slide under the 
microscope, bundles of fibres will be perceived, which with 
needles and a little patience may be separated into portions, 
Bome of these being striated, or marked with alternate spaces 
of dark and light. Some of the non-sfriated or smooth class 
of mnscle, snch as is found in intestines, may be prepared 
for the microscope by immersing for a day or two in nitric 
Bcid diluted with three or four parts of water, and then 
separating with needles and mounting as eoon as possible. 
Sometimes bailing is resorted to to facilitate the separa- 
tion, and occasions Uttle or no alteration in the material. 



nniler water with a fine camel-hair brasli very gently. 80 W 
to remove tlie precipitatea of tbe gold Bait. Sections of 1 
cornea so prepared maj be made on the finger b; a shaig 
razor, aod must be etamined and kept in gljcerioe. 

Liver, Kidney, Si'Leen, Lung, Ac. — Some parts wl 
are too sofl to be cnt into aections in their ordinary Bt 
are ngnally hardened by being eteeped ta a aolntion 
cbromia actd, aboat two grains to aa ounce of water. Thi 
win take HOme weeks according to the eubRtance, and U 
eolation abould be changed now and then. Dr. Baatian, la 
moanting, uaea Canada balsam partially dried to dispel tl 
tttrpeatine, and then dilated to necessary coDsistence i>" 
benzole. The section being cat from the hardened ai^aaj 
washed in spirits of wine for some minutes, then a drop e 
liijuid carbolic acid is placed on the slide where the sp 
men is to be mounted. Take the specimen and let ite e 
toach a piece of blotting-paper, and place it apon 
carbolic acid, which will render a thin section transparen 
in about a miante. Bsmove the soperflaoaa acid * 
blotting-paper, when two or three drops of chloroform n 
be poured upon the section and remain one ininnte. Droi 
off and place npon the object the solution of Canada balsai 
in benzole, and apply the thin glass cover. Or place 
object in ordinary spirits of wine for about a minute to i 
it, then remove into absolate alcohol for five minates. 
it upon the elide and drain, cover with one or two drops C 
benzole for about a miuute, tilt to drain off, and proceed (U 

Both these luetboda are good, but the first does n 
always answer for sections of liver, aa they generally a 
acted upon by carbolic acid; but few other tissues a 
affected. Tinted specimens seem equally safe wlien monntej 

Sections op BjtiiN akd SriSAt Conn,— Dr. Baatiai 
gives hia experience of these tissues as follows :—I. ii 
tbe section for about ten minutes in absolute alcohol dilat 
with eight per cent, of water, then place uiion the glai 


slide, and before it becomes dry poor over it two or three 
drops of pjroacetic acid for about half a miaate. Tilt this 
off and replace bj chloroform. Watch the effects, as before, 
under the mioroBcope, and then cover with the Canada 
balsaoi solution and fioish. These specimens, howeTer, are 
not always permanent in their appearance, according to the 
res nits of some. 

Mr. Alfred Sanders gives his expeiieneo aa differing some- 
what from this. Ho says — The brain, or other structore, 
'□g, as QSual, hardened in chromic acid, the section is put 
for a short time in spirits of nine, and thence transferred to 
the creosote, which taakes it transparent in a fen minates, 
when it ia placed in Canada balsam. The balsam will mix 
easily with the creosote, or the solntiou in benzole may bo 

TiACHB« o? Insects, &o. —The nature of theae was de- 
acribed in Chapter IV,, but the method of proonriog them 
was not explained, as this clearly belongs to diesecUon. 
The larger tubes are readily separated by placing the insect 
a water, and £xiog as firmly as possible, when the body 
nust be opened and the viscera removed. ThotracheiB may 
hen be cleaned by the aid of a camel-hair pencil, and 
floated npon a glass, where they must lirst be allowed to dry, 
and tben be mounted in balsam. Mr. Qaekett gives the 
following method of removing the tracheal from the larva of 
n insect; — "Make a small opening in its body, and then 
place it in strong acetic acid. This will soften or decompose 
bU the viscera, and tbe tracheae may then be welt washed 
with the syringe, and removed from the body wilh the 
greatest facility, by cutting away the connections of thu 
in tubes with tbe spiracles by means of 6ue-pointed 
soissors. In order to get them upon the slide, it must be 
pnt into the fluid, and the tracheal iloated npon it ; afcer 
which they may be laid ont in their proper position, then 
dried and mounted in bLiIsam." If we wish them to bear 
ir natural appearance, tbey must be mounted in a cell 
with Goadby'fl fluid i but the structure ia emiieliiiiee _well 

akf^ipdar witk cUwofera. I left itmM 
B or c^U dafi. nb tmtMDt i ~ '^ 
BtaMer AiB of iuccte and canaca Ae viM 
I'tobMiVt tbrongk th« onttf uAcgamcat, mad it I 
•t*t«, pethaf, that Uie pouo« gUtnSM arc ino«t aaan;f di 
eofttfA and traced to tbcir point* of attaebment. 
drew tha roandiUea from Hie bodj, and, having plai 
tii«m iritli a little wat«r cm a elide and covered them tritli a] 
pieM of thin glaes, I fooud that, upon the applicatioa o 
preeiore, the two glands ehot oat and protrnded from thai 
Inwf of the mandlblei. I tore open one of the mandiblKfl 
with needl(>«, bo as to distDrb the gland as little as poBBible..t 
Thn ginnd then appeared as a closed aac, attached bj S 9 
hollow norc], almiit the length of the gland itself, to the bi 
of tha fang, where also was a large bnndle of maBColai' 

Frdii,— The moat interesting part offish to then 
■oopio anatomiat is andoubtedlj the hreathing apparatn 

or KicBoscoPic owtCTS. 169 

■ It IB not a very diEcnIt matter to oppn the head and remote 
the gills, which are Tery beantifiil. Uo^er the oaler covers 
lie a quantity of thin plates or leaves (as of a book) nbioh 
in different fishes are of varioas shapes, bnt are made like 
net-work hy the Dnmerons veios and arteries which convej 
the blood to be acted npon by the air and gases in the 
water, as is dooe in the lungs of a man. These platee are 
of such numbera that in a good-si^cd salnion the Enrface 
eiposed has been estimated at two thonsatid Kqnare inches, 
i.e., abont fonrteen aqnare feet. The beanty of these is, 
of oonrae, not •perfedhj shown nntil they are injected, which 

' will be noticed elcewhere. 

Tongues, or Pawtes, of MoiLusns. — Of the nature of 
these, Dr. Carpenter gives the folloning description ; — "The 
organ which is commonly known nnder this designation is 
one of a very singular natnre ; and we should be altogether 
wrong in conceiving of it as having any likeness to that on 
which onr ordinary ideas of such an organ are founded. 
For, instead of being a projecting body, lying in the cavity 
of the month, it is a tube that passen backwards and down- 
wards beneath the mouth, its higher end being closed, 
whilst in front it opens obliquely npon the floor of the 
mouth, being, as it were, slit np and spread out so as to 
form a nearly flat snrface. On the interior of the tube, as 
well aa on the flat expansion of it, we Snd numerous trans- 
verse rows of minute teeth, which are set upon dattoned 
plates ; each principal tooth sometimes having a basal plate 
of its own, whilst in other instances one plate carrica 
several teelh." These palates, or tonguca, differ much 
amongst the Gasteropods in form and size, some of them 
being comparatively of an immense length. Many are 
amongst the most beautifal objects when ejcamine^l with 
polarized light, Tbey must, however, be piocnreil by dii- 
•eetioD, which is osuajlj performed as follow! : — The animal 
ii placed on the cork in the dissecting-troagb before men- 
tioned, and the head and forepart cnt open, spread ont^ aod 
firrolj pinned down. With the aid of fine iciuora or knif«, 


the tongue miut be then detached from its fasUniogs, ani 
ptac«d in water for a day or two, when all foreign matter ntf 
with a little care be removed. lo what way it ahonid b* 
moDnted will depend on the purpose for which it is iutendtd. 
If for examinatioD aa an ordinarj otgect, it ma; be !>» 
upon the slide and allowed to drj, which arrangement "Qi 
bbow the teeth very well. If we wish to see it as it is nato- 
rally, it wiiBt be monnted in a cell with Goadby's flaiij ; lint 
if it is wanted as a polarizing object, it must be floated npuii 
a slide, allowed to dr; thoroughly, and then Canada ' 
added in the usual manner. 

Id the stomach, also, of some of these molluBCs teeth ut 
found, which are very interesting objects to examine, aau 
must be dissected out in the same ma.nner as ti 

Since writing the above, Dr, Alooct (whose very bea 
tiful specimens prove him to be a great authority in tt 
branoh) has published some of bis eiperience in the eecoi 
volume of the third series of " Memoirs of the Literary a 
Philosophical Society of Manchester." By his permission C 
make the following extract : — 

■■ This closes my present commnnication on the tongaw 
of molluaca ; but as some members may possibly fed 
inclined to enter apon the inqoiry themselves, I think il 
will not be amiss to add a few remarks on t 
which they are to he obtained. 

" First, as to the kinds best worth the tronble of pHK 
paration. Whelks, Limpets, and Trochnses sbonld be ti ' 
tirst. Land and fresh-water Enaih can scarcely be ret 
mended, except as a special study, — their tongues beii^ 
rather more difficult to find, and the teeth so small tha 
they require a high power to show them properly, 
wonld appear, from SpallaDEani's description of the aaatoinj: 
of the head of the snail, that even he did not make out thil 
part, although, in bis curious observations on the reprodafl 
tion of lost parts, be must have carefully dissected c 
I snails than any other man. 

OF uiCRosconc OBJECTS. 171 

Aa to preserving the animals till waoted, the? should 
aimply be dropped alive into gljcerine or alcohol. Gljcarine 
ia perhaps beat where only the tongues are wanted ; but it 
leaves the animals very sott ; and as it does not hardea 
their mucns at all, thej are very slippery and diiEonlt to 
work npon when so preserved. 

" Then as to the apparatus required for dissection. In the 
first place, all the work is to he done nnder water, and a 
com mo a saucer ia generally the most convenient vessel 
to use. No kind of fastening down or pinning oat of the 
animal is needed ; and, in fact, it is much better to have 
it quite free, that you may tarn it about any way jou wiah. 
The necessary iuatrnments are a needle-point, a pair of 
fine-pointed scissors, and small forceps ; the forceps should 
have their points alightly turned in towards each otter. 

"A word or two on the lingual apparatus generally, and 
on its special obaractera in a few difierent animals, will con- 
olade what I have to say. 

"The mode of using the tongue can be easily seen in any 
of the common water-snaila, when they are crawling on the 
glass sides of an aquarium ; it may then be observed that 
from between the fleshy lips a thick mass is protruded, with. 
a motion forwards and upwards, and afterwards withdrawn, 
these movements being almost coutionally repeated. The 
action has thu appearance of licking; but when the light 
falls suitably on the protruded structure, it is seen to be 
armed with a number of bright points, which are the lingual 
teeth, BO arranged as to give the organ the character and 
action of a rasp. 

"If JOQ proceed to disaectiOD, and open the head of one 
of these moUusca (say, for instance, a common limpet), yoa 
will find the cavity of the mouth almost filled with the thick 
fleshy mass, the front of which ia protruded in the act of 
feeding ; and on its upper surface, extending along the 
middle line from back to front, is seen the strong membranoaa 
band upon which the teeth are set. The mass itself consiata 
of a cartilaginous frame, Bnrrouaded by strong muacles ; and 

172 phefabatiox akd moestisq 

these stractareB constitate the whole of the active part ol 
the lingDal appara,tD8. 

"Hat the pecoliaritj of the toothed membrane, nhioli 
males its oame of Hlhon so appropriate, is, that there is 
alnajB a cortsiiJerable length of it behind the moath, per- 
fectly formei3, and ready to come forward and aopplj the 
place of that at the froQt, which is conliouallj wearing anaj 

'J"'- .... 

" In the limpet this reserve ribbon is of great lengtfai 
being nearly twice as long aa the body, and the whole of it 
is exposed to view on simply reoioviiig the foot of the animal; 
nothing, then, can be easier than to eilract the tongue of 
the common limpet. But, unfortunately, what yon find ii 
one kind of mollusc is not at all what yoa find in another. 
In the Acmieas, for instance, which are very closely related 
ia the limpets, and bavo shells which cannot be diatingatehe^ 
the reserve portion of the ribbon has to be dug out from tl " 
anbatance of the liver, in which it is imbedded, that orgi 
being, as it were, stitched completely Ihrongh by & lo: 

loop of it It might he thonght a comfortabli 

reQection that, at all events, one end of the ribbon t 
always be fonnd in the mouth; but iq many cases this 
abont the worst place to look for it. Perhaps it may appaa 
etrange that in some of the smaller species, with a, retractil 
trunk, a beginner may very likely fail altogether in I 
attempt to find the mouth ; if, however, the skiu of the ba 
be removed, oominenoing juab behind the tentacles, there « 
be very little dlfiicalty in making out the trunk, whioheiths 
contains the whole of the ribbon, aa in the whelk, i 
front part of it, as in Pinjiura and Mitrex, where . 
coil is also seen to hang from its hinder eitremity. . . 
In the periwinkles the same plan of proceeding, by at on; 
opening the back of the animal, is best : and on doing W 
the long ribbon, coiled up like a watch-spring, cannot failt 
be found. 

" la the Trochusea, and indeed in alt the ScnlibraTuAiatl 
one point of the scisaora should be introduced into t 



montli of the tiiiiniBl, and an inciaioiL made directly back- 
wards in the middle line above to some distance bebiud the 
tentacles; the tongoe ia then immediatelj brought into view, 
Ijing along the floor of the mouth." 

Dr, Alcock's method of disaection will he found to differ 
in some degree from the general rules before given ; and 
when the tongue ia dissected out be washes it for one hour 
(ahabing it no^ and then) in a weak solution of potash. 
After cleaning tboronghly in water, it must be mounted by 
one of t1ie methods before mentioned. 

Mr. Edwards, of New York, no moan authority, gives hia 
experience as follows : — I nse a rather strong solutioQ of 
canatio potaasa, the strength of which I cannot specify aa it 
mnst differ with the species under manipulation, as some 
ribbons (or tongues) are injured much sooner than others. 
Plunge the whole animal ia this solation; in the case of 
very small creatures shell and all. I have found it better 
to let the animal etand nntil it dies and begins to decom- 
pose, when it can readily be removed and falls in pieces. 
The lingual ribbon is not so easily decomposed. Now place 
and leave the animal in the pota.Bsa solution for some days, 
or boil at once. Almost everything is now dissolved bat 
the shell, some fet? fragments, and the desired ribbon. 
"Wash carefully with fresh water, and if it is to be preserved 
before mounting, remove to alcohol. To mount it, remove 
from the spirit and boil a short time in, turpentine, when it 
can be pnt up in Canada balsam. Mr. May espresses him- 
self as " standing utterly agliast " at any man so interfering 
with nature as to put up theae objects in balsam, thus 
pressing and destroying their true forms. He recommends 
a cell and a weak form of Goadby's solution. 

Amongst insects, especially the grasshopper tribe, are 
found many which possess a gizzard, armed with strong 
teeth, somewhat similar to those of the mollosca. It 
requires great nicety of manipulation to obtain theae for the 
mioroBCope; but Mr. L. G. Mills, before quoted, gives the 
following instructions :— Kill the insect with chloroform and 


place it in a yeeeel of water. Hold it down firmly witli a 
pair of tweezers, and with the back of a dissecting knife 
draw the head steadily from the body. The heard brings 
with it the stomach, gizzard, and chief portion of the digestive 
tnbes. Place all these nnder a dissecting microscope, when 
the gizzard, being jnst below the stomach and darker in 
colour, is easily distinguished, and may be separated by two 
cuts with the knife. It then forms a short tube, the teeth 
being inside. The opening-out of this tube, especially if it 
be small, requires delicate handling : if the point of a fine 
knife can be fairly inserted, then one firm cut downward 
upon the glass will lay open the gizzard. Here great care 
is needed ; and sometimes it is well to put a fine needle up 
the tube, and cut down upon the needle. Among the 
small weevils the membrane is delicate, so that great care 
is necessary. 

We have now considered most of those objects which 
require any peculiar treatment in section-cutting, &c. ; but 
in no branch of microscopic manipulation is experience more 
necessary than in this. 



1. Injection is the filling of the arteries, veins, or other 
vessels of animala wilK some coloured substance, in order 
that their nalnral arrangernent may be made visible. This 
ja, of conrae, a delicate operation, and needs special appa- 
ratna, which I will now attempt to describe. 

"2. Sip-ingB. — This is nsnally made to contain abont two 
onncBB. On each side of the part Beit to the handle is a 
ring, so that a finger may be thrust throogh it, and the 
tharab may work the piston as in an ordinary syringe. 
The plug of the piston most be packed with soft leather 
welt oiled or greased, in order to free it from all danger of 
any liqnid penetrating it, and fit so closely as to be perfectly 
air-tight ; and if, when it has been used awhile, it is fonnd 
that some of the liquid escapes past the ping into the back 
part of the body, it mnst be repacked, which operation will 
be beet understood by eraminiog the part. These syringes 
are made of variona sizes, hot in ordinary operations the 
above will be all that is needed. The nozzle ia about an 
inch long, and polished so accurately that there is no escape 
when the j>ij)*s are tightly placed upon it dry. 

3. The pi2>es are nanally abont an inch long, to their 
ends are afiiied thicker tnbes bo as to fit the nozzle, as 
before mentioned, whilst a short arm prnjecta from each 
side of these, so that the silk or thread which ia nsed to tie 
the artery npon the thin pipe, may be carried ronnd these 
arms, and all danger of slipping off prevented. The }>!pfs 
are made of different sizes, from that which will admit only 
of a very fine needle (and this will need now and then to be 
cleaned, or to be freed from any chance obstruction), to 


raEFiBAHOs isn mottsiixs 

that which will take « large pin. These aizeB rnuBt alwajs 
be at h&nd, as the vessela of BOme subjects are eiceedmgty 

4. SlopcocJi. — This is a short pipe like a Bmall slrai^lii 
tap, which fits Bccoratelj upon the end of the syringe like 
the pipes, and also takes the pipes in the same oianne 
The nso of thia is BbBpIntely neceseary when the object 
BO large that one ayringe full of liqaid will not fill it. 

DO pteTeotiie were ased, some part of the liquid woald 
return whilst the syringe was being repSeuished, bnt tha 
stopcock ifl then turned as in an ordinary tap, and all 
danger of thia eSectnally removed- 

5. Cui-ved needles. — These are easily made by heating 
common needles at the end where the eye is situated, and 
bending them with a small pair of pliers into a eegment of 
a circle half an inch in diameter. They are, perhaps, mora 
convenient when the bent part is thrown elightly hack 
where it commences. The pointed end is then tbrnst into 
a common penholder, and the needle needs no re-tempering, 
as the work for which it is wanted is simply to convey tha 
thread or silk inuler any artery or vessel where it wotdd bo 
impossible to reach with unaasiated fingers. 

6. A kind of forceps, commonly known by the name ot 
"balldog forceps," will he constactly required daring tlii 
process of injecting. These are short, nsoally very 
but not heavy, and close very tightly by their own Hpring^ 
which may be easily overcome and the artery so released bj^ 
the presBOTo of the fingers. When any vessel has not been 
tied by the operator, and he fiods the injected Quid escaping, 
one of these " balldoga " may be taken up ai " "' 
close upon the opening. This will cause i 
terruption, and the stoppage will be almost 
if it were tied, 

7. When the ordinary mode of injection i 
is necessary that the preparations he kept wa 
time they are uecd, otherwise the gelatine or t 
contain becomes stifle, and will not allow of being worked by 

id allowed ta 
little . 

employed, it 

m daring tho 

which they 

OF uicRosconc ojjJECTs. 177 

■ the Byringe. For this pnrpose we mast procure Bmall 
earthenware or tin pots of the size required, which will 
differ accordiog to the kind of work to be done ; and to each 
of these B. loose lid shonld be adapted to protect it from 
dnat, &c. These pots must he allowed to stand in a tin 
hath of water, nnder which a lamp or gas flame may be 
placed to keep the temperature eufiicientlj high to insure thd 
perfect fluidity of the mixture. The tin bath is, ])erbaps, 
most convenient when made like a smalt shallow cistern ; 
but some oIobo it on the top to place the pota npon it, and 
alter the shape to their own cDnvenience. 

8. We will now inqnire into some of the materials which 
are needed in this operation ; the first of which is sisr. 
This sabstance is often used in the formof jfue, hut it mnst 
be of the very heat and most transparent hind. To make 
the liquid which is to receive the colours for the nsnal moda 
of injecting, take of this glue seven ounces, and pour npon 
it one qnart of clean water; allow this to stand a fevr 
honra, and then boil gently nntil it ia thoroaghly dissolved, 
stirring with a wooden or glass rod during the process. 
Take all impurities from the surface, and strain through 
flannel or other fine median). The weather affects thi-i 
a little as to its stiflhess when cold, hat thia must b<i 
coonteracted by adding a little more glue if found too 

9. Inataad of glue, gelatine ia generally used, especially 
when the work to he accomplished is of the finer kind. Tbd 
proportions are very different in this case, one ounce cf 
gelatine to about fourteen ounces of water being suflicient. 
This, like glue, must be soaked a few hours in a small part 
of the cold water, the remainder being boiled and adder<, 

' when it mnst be stirred until dissolved. A good siis muy 
be made by boiling clean strips of parchment for awhili-, 
and then straiging the liquid whilst hot through flannel j 
bnt when the injections are to be ti-anaparent, it is of the 
greatest importance that the size be aa colonrlesa as pos- 
aible. For thiii t^urpose good gelatine must be employed. 



H,B Kelson's or Coi's: some persons of eiperience preTer th» 

10. Colours.— The ske-Bolution above mentioned will 
need some colonring matter to render it viBtble when in- 
.iected into the vesBela of an animal, and different coloniB 
are used when two or more kinds of Teasels are bo treated, 
in order that each set may he easily distingnished by 
sight. The proportion in which these coloors are added to 
the aize-aolution may be given as follows : — 

11. For 

Bed 8 parts of size-solution 

(by weight) to 1 part of vermilion. 
Yellow... 6 „ „ 1 „ chrome yellow. 

White ... 5 „ „ 1 „ flake-white. 

Bine 3 „ „ 1 „ blue-smalt, fine. 

Black ...12 „ „ 1 „ lampblack. 

WhicLevor of these colours is used must be levigated ii 
mortar with the addition of a very email quantity of wateo: 
until evpry lump of colour or foreign matter is reduced to' 
the £nost state possible, otherwise in the process of injecting 
it will moat likely be found that some of the small chaitDelw 
have been closed and the progress of the liquid stop[»ed. 
^yhen this fineness of particles is attained, warmth sufficieab 
to render the size quite fluid must be used, and the ooloar 
added gradually, stirring all the time with a rod, It may 
be here mentioned that where one colour only is reqoirad, 
vermilion is, perhaps, the best ; and blue is seldom used 
for opaque objects, as it reflects very little more light than 

12. When it is wished to fill the capillaries (the minnte'] 
vessels connecting the arteries with the veins), the Micr< 
graphic Dictionary recommends the colouring matter to 
made by double decomposition. As a professed handbookJ 
would be, perhaps, deemed incomplete without somi 
tions as to the mode of getting these colours, I will h< 


given in that wort. For red, however, vermilion, 
Btated, may be used; but it nmst be carefully 
examined by reflected light to aee whether it be free from 
all colonrleaa crystals or not. It mnat first be nocked in a 
mortar, and then the whole thrown into a quantity of water 
and stirred about ; after leading it not longer than a qnarter 
minute, the larger portions will settle to the bottom, 
and the liquid being ponred off will contain the finer powder. 
This may then he dried slowly, or added to the eize whilst 
it in the manner before advised. 
13. 7elIovi injection. — To prepare this, take — 

Acetate (sugar) of lead SSO grains. 

Bichromate of potash 132 „ 

Size 8 ounces. 

Dissolve the lead salt in the narm size, then add the bichro- 
mate of potash finely powdered. 

free, and ia wasted ii 

Some of the chromic acid 
this aolntion, so the following is given ; — 

Acetate of lead 190 grains. 

Chromate of potash (neutral) ... 100 „ 
Size 4 ounces. 

The first of these has the deepest colour, and is the most 
generally used. 

14. White injedion. — This is a carbonate of lead ; — 

Acetate of lead IPO grains. 

Carbonate of potash kH „ 

Size 4 ounces. 

DisaolTe the acetate of lead in the warm size, and filter 
through fiannel; disaolva the carbonate of potash in the 
emallest quantity of water, and add to the aize: 143 
grains of carbonate of soda may be snbstitnted for the car- 
bonate of potash. 

15. For bine injection, whick ia not, toweyer, muoli QM 
with reflected light, tu before atoted, take — 

ProBHiaii blae 73 ^oins. 

OiaJicacid 73 „ 

Size 4 oQiioea. 

The oxalic acid is first fioely powdered in. a mortar, i 
Pmssian blae and a little nater added, and the whole th 
thorooghly miied with the eize. 

16. It raaj here bo repeated, that it is only when tb 
capillaries are to be filled that there is any need to be at U 
trouble to prepare the colours bj this doable decompoaitiol 
and, indeed, coloars ground so finely maj be procured ibl 
the above ioBtrnctions would have been omitted, had it n 
been supposed that some students might find a donble pleil 
sure in performing as mnob of the work as passible bj the!) 
own unaided labonrs. 

17. The process of injection may now bo considered; 
it is impossible for written instructions to supply the plai 
of eiperience. I will do my bust, however, to set the n 
at least in the right way. There are two kinds of injeotio 
— one where the object and colonrs are opaqae, and oo 
quently fit for examination, by reflected light only; 
other, where the vessels are filled with transparent colone 
and mnst be viewed by traKsmiiled light. The first of the) 
is most frequently employed, so we will begin with it. 
the object which is to be injected, a vessel of the kind whi 
we wish to be filled mnst be found ; an opening must ths 
be made in it to allow one of the small pipes before n 
tioned to be thrust some distance within it. When this il 
accomplished, thread the curved needle with a piece of nil 
thread, or very fine string, which some operators ruT 
wilh beeswai. This thread must not be too thin, else 
is danger of catting the vessel. The cord is then c 
under the inserted pipe, and the vessel bound tightly Dpon 
it, the ends being brooght np round the transverse armn^ 

OF uicBOsconc OBJECTS, 181 

Bad there tied ; so that all danger of accidentallj with- 
drawing the pipe is obviated. Care mnst now be used in 
cloaing all the veaaelB which commmiicate with that where 
the pipe is placed lest the injecting fluid escape j and thia 
mnst be done by tjing them with silk. Should, however, 
any of theBa be left open by ^cident, the bulldog forceps 
tniiBt be naed, as before recommended. 

18. The part to be iojected must now be immersed ia 
Wftrm water, not, however, above 100° Fahrenheit, and left 
until the whole ia thoronghly warmed. Whilat this is being 
done, the coloured size most be made ready by the pot being 
placed in the tin bath of warm water, which mast be of 
jnEBcient temperature (about 110° Fahrenheit) to keep it 
perfectly liquid. For the aame purpose, the syringe ia often 
tigbtly covered with two or three folds of flannel; and, 
indeed, there is no part of the process which requires mora 
attention. If the anbatance to be injected is too hot, it is 
injured; whilat, if any of the articles are too cold, the gela- 
tine, or size, loses a part of its Haidity, and consequently 
cannot enter the minute vesaels. When all is prepared, the 
syringe, with the stopcock attached, should be warmed, and 
then filled aad emptied with the injecting fluid two or three 
times, care being taken that the end of the syringe be kept 
beneath any bobblea which form upon the surface. The 
syringe may then be tilled, and closely attached to the pipe 
which ia tied in the vessel. Wif h a firm and steady pressure 
the piaton must be forced downwards, when the substance 
will be perceived to swell, and the colour show itself in places 
where the covering is thin. When the ayringe is abiiosl 
emptied of ita contents, the atopcook muat be turned to pre- 
vent any escape of the injection from the subject. It must 
then be refilled, as in the £rst instance, and the process 
repeated. I say almost emptied, because it is well not to 
force the piston of the syringe quite to the bottom, lest the 
small quantity of air which frequently remains be driven 
into some of the vessels, and the object be injured or quits 
ruined. As the injection is continned, it will be found that 


FKzrxKAxica AXD xovs-nsa 

the force repaired grown greater, jet emre iniut be talcen cot 
to n»e too mach, or the tbsmIi will bant, and render all thft 
l&bonr fmitleae. The morement of the piston moat be 
occa/BoaaiOf so slow aa to be almost itoperceptible, and foi 
this reason tlie piaton-rod is Bometimee marked with L' 
about one-^gbtb of an inch apart. 

19. Of coarse, daring the whole procesa the injeetiu^ 
fluid and sabject moat be kept at a temperatare high enougli 
to allow the liqnid to flow freely ; and the escape of a little 
of it need canae no fears to the operator, as it ia almost im- 
pMsible to fill a subject wiUioQt some loss. When the 
injected object has received sufficient flaid, it shoald hare a 
plump appearance, owing to all the TeBBela being well GlletL 
The vesBel must then be tied np where the pipe was inserted 
and tbe whole left in cold water two or tbree houie, & 
which time it majr be monnteU ; bnt it maj be well to no 
a few things which the beginner onght to know before enter- 
ing into that part of the process ; and be maj be here informed 
that it is not necessary to mottat the objects immediately, 
otherwise it would be impossible for one person to make. 
use of half of any large anbject, as it would be in a state 
of decay long before each part conld have been examined; 
and separated. Large pieces shonld be therefore immersed 
in eqoal parts of spirits of wine and water, or glycerin* 
which some think better still, and thus preserved in bottlei 
until time can be given to a closer examination. 

20. In operating npon large Bnbjecta, entire animals, i 
the constant pressure required by the piston of the syringel 
grows wearisome, besides occapying both hands, which if 
sometimes inconvenient when working without assistaocft 
To obviate this, another way of driving the syringe war 
published in the Micrographic Dictionary which I will 
qnote here ; — " We have therefore contrived a very simple 
piece of apparatas, which any one can prepare for himself 
and which effects the object by mechanical means. I 
eists of a rectangular piece of board, two feet long and ten 
inches wide, to one cud of which is fastened an inclined' 


piece of wood (eqnal in width to the long board, and one 
foot high). The iachned portion is pierced with three holeg, 
one above the other, into either of which the Hyriuge may 
bo placed — tlie appermoat being need for tho larger, the 
lowermost for the emaller syringe ; and these holes are of 
inch size as freely to admit the syringe covered with Sannel, 
but not to allow the rings to pass throngh them. The 
lower part of the syringe is supported upon a semiannular 
piece of wood, fastened to the upper end of an upright rod, 
which slides in a hollow cylinder fixed at its base to a small 
rectangular piece of wood ; and by means of a horizontal 
wooden screw, the rod may be made to support the syringe 
at any height required. The handle of the syringe is let 
into a groove in a stout wooden rod connected by means of 
two oatgut strings with a smaller rod, to the middle of 
which is fastened a string playing over a pnlley, and at tho 
end of which is a hook for supporting weights, the oatgut 
strings passing through a longitudinal slit in the inclined 
piece of wood." When in use the syringe is filled with 
injecting Quid, and passed throngh one of the three holes 
which is most suitable. The object being placed so that the 
pipe and syringe can be best joined, the rod and strings are 
set in order, and a weight placed oa the hook. The stop- 
cock must then be opened gradually, when the operator 
will he able to judge whether the weight is a proper one or 
not : if the piston is driven with any speed, there is danger 
of injuring the snbjeot, and less weight may be nsed ; ii', 
however, the piston do not move, more must be added.' 

21. Such is the method recommended in the Micro- 
graphic Dictionary, and perhaps it is as good as any 
mechanical plan oould be ; but where the operator is wilUng 
t« undergo the labour of performing all this with the band, 
he has a much better chance of sncceeding, because the 
pressure can be regulated so accurately, and changed so 



qoicbly when rcquiHite, that no mere machine can compete 
with it, however well contrived. 

22. When the beginner attempta to inject a subject, one 
of his difficnltieB is fioding the vessel from which to 
mence. Another coneista in diBtinguishing the arleriea 
from the veins ; bat this ie parttj removed by nalnng B 
longitadinal incision in the vesBel, and with a lilant thick 
neKlle probing a little distance into the tnbe. The artery 
will be found thiclier in the coating than the vein, and tb» 
difference ia easily perceived by this mode of testing: the 
vein is also of a bluer coloar than the artery. I saj' abovS) 
a. " longitudinal incision " moot be made ; the reason for thii 
ia, that an artery when cnt acroea contracts considerably, 

is lost in the adjoining Bobstance ; but where the openiog 
is made longit'iidinaU!/ all danger of this contractioa it 

23. The different systems of vessels are often injected 
with varioos coloore, so that the4r relative positions, 
may be shown more clearly. In some specimens, the vein! 
are injected with white, and the arteries with red ; ii 
kidney, the urinary tabes are often filled with white, 
the arteries with red. Then, again, the liver affords tabel 
for three or fonr colonra. Bot no written instructions on 
this poiot can benefit the young student, and he mnst 
content for a while to employ himself with single colours 
nntiL he has gained the mechanical skill and the primary 
knowledge which are necessary before he can make any 

24. We will now consider the best methods of mounting. 
injected objects. They must always be well washed in 
water after they have been kept in any preservative liquid, 
iisiug a camel-hair pencil to clean the surface if necessary- 
Many parts when injected are in masses, such as the lungs, 
liver, Ad,, of animals, and consequently sections of thew 
must be cnt. For this purpose Valentin's knife is veij 
con''enient, as the thickness can be regulated so easily ; bnf 
where the injections are opaque, tliere is no need to have the 

or Yicaoscopic osiects. 185 

B very thin. Some few of tlis liiod undergo corapara- 
tivelj little cbange in drying, ho that the section maj be 
well washed and floated upon the glass elide in the plaoe 
desired, where it will dry perfectly and adhere to it. It 
mast then be moistened with turpentine and monnted in 
Canada halsam like other objects. No great heat shoold be 
need with these preparations, as it is very liable to injure 
them; and some of the colours eeem to suffer a slight con- 
traction when any great degree of warmth is applied. There 
are many objects, however, which mnat be seen in the masa 
to be Ttsderstood, and, indeed, lose all their form and beauty 
'n drying, such as certain parta of the intestines, ito. These 
mnst be monnted in finid, with the precautions noticed at 
'a Chapter T., and for this purpose either Goadby's 
flnid, the chloride of zinc solution, or spirit diluted with ten 
parte of distilled water, may be employed. It is a good 
thing, when practicable, to mount similar objects on two 
separate elides, using different preservative liquids, and 
tabing the precaution of marking each with the kind of 
liquid employed. This not only serves as a guide to what ia 
best for certain eubjeots, but if one is injured, there will 
probably be a good specimen in the other. 

2b. It may be here mentioned that many are now mount- 
ing sections of injected subatBDces with the balsam and 
chloroform before mentioned, instead of using balsam alone, 
and consider that the labour is mnch lessened thereby. 

".A description of that mode of injection which is most 
generally employed baa now been given, but this is not the 
only method of effecting oar object. A most iugenioue 
process was invented by M. DqyBrs, requiring no artificial 
warmth, by which many beautiful objects have been pre- 
pared. Make a solution of bichromate of potash, 524 grains 
to a pint of water, and throw this into the vessels to be 
injected ; then take 1,000 grains of acetate of lead dissolved 
'u half a pint of water, and force this into the same vessels. 
A decomposition now takes place iu the vessels, and the 
yellow chromate of lead is formed. In this decomposition. 


hoirever, the acetate of potasb also is formed and aa i 
Halt haa an injurious action apoD the cells, Br. Goadb] 
recommends nitrate of lead to be used, which preBerTB 
rather tlian deetrojs them. He also advises the addition 
of two ounces of gelatine dissolved in eight ounces of watto^ 
to eight ounces of the saturated solution of each salt; but 
with this addition the hot-water bath would be required b 
keep the injecting fluid liquid. 

27. Many of these b.tb best tnounted in balsan, in tliA 
same tnauiier as those made in the ordinary way ; whilst 
others are beat shown when preserved in liquids, for which 
purpose Goadby's fluid may be employed, 

28. This mode of making iujectious with chromate of le 
is deemed by many the best, especially where one colon* 
only is employed. But it must be allowed that there is 
little more danger of failure where two separate fluids a 
used for the same vessels. 

29. We will now consider the best manner of making 
iran^aTeiii injections, which, for many purposes, poaaesa a] 
undoubted advantage over opaque ones. But it must b 
remembered that there are certain subjects to which n 
transparent injection could be applied, as they are too thiol 
when iu their natural state, and cutting would destroy tl 
that beauty which is shown by the difierent parts in 
Tslative adaptation. For those objecta, however, v 
must be cat into aectiona to display their wonders, o 
naturally thin — such as some of the finer tisaues, liTerft 
kidneya, &c., — transparency is a great acquisition 
enables us to nudoratand the arrangement of the veaast 
more perfectly. Again, another advantage is the simplioifj 
ot the process ; no hot water is needed with some 
parations, either for the subject or the injecting fluid, i 
runs into the minute vessels thoroughly and easily, whili 
the cost is small. 

30. For this kind of injection no colour is so con 
used as Prussian blue. It is not a good one, as was 
stated, for any opaque object, the light reflected from : 

OP aicKoscopic OBJECTS. 137 

appearing almaat black ; jet hy traiiemitted light no colour 
IB more uBefuI, beeanae its distinctness is equally great by 
artificial ligbt acd ordiDarj dajligbt. Tb.a method of pre- 
patiDg this, as given by Dr, Beale, ia as foUoira: — 

Glycerine 1 oonce. 

Wood naphtha, or pjroaoetic acid 1^ drachm. 

Spirits of wine 1 ouQce. 

Ferrocyanide (yellow pmseiate) of potas- 

Bium 12 grains. 

Tinctaie of seaqnichloride of iron 1 drachm. 

Water 4 ounces. 

DisBolve the ferrocyanide of potassiam in one onnce of the 
water ; add the tincture of aesqoicbloride of iron to another 
ounce. Mix theae solutions gradoally together, shaking tho 
bottle well which contains them — it is beat to add the iron 
to the potaah solntion. When thoroughly mised, these 
Holntions shontd produce a dark -bine mix tore, perfectly 
free from any perceptible masses or flocculi. Noit mis tho 
naphtha and spirits of wine, and add the glycerine and the 
remaining two onncea of water, Thia mnat now bo slowly 
mixed with the blue liquid, shaking the wliole well in a 
large bottle whilst the two come together. The tincture of 
sesquichlorido of iron is recommended, because it can always 
be obtained of a uniform strength. 

31. Dr. Torobnll ased a mixture slightly different from 
the above, nhich is made with the sulphate of iron: — 

Forified snlphate of iron 10 grains. 

Ferrocyanide of potaaaium 32 grains. 

Glycerine 1 ounce. 

Fyroacetio acid 1^ drachm. 

Alcohol 1 ounce. 

Water 4 onncea. 

Ilissolvo the sulphate of i 

of the water. 


gradually add the ferrocyanide of potaSBinm diasolved 
an-other ounce, and proceed aa before. 

32, Dr. Benle altio gives ua the following carmine injection 
to be employed ia the same way as the blue.* Take — 

Carmine b grains. 

Glycerine, with 8 or 10 dropg of hydro- 
chloric acid i onnce. 

Glycerine (pure) 1 onnoe. 

Alcohol 2 droohme. 

Water 6 drachinB. 

Mix the carmine with a few drops of water, and when well 
incorporated add about fire drops of liquor ammonia "" 
this dark-red aolotion abont half an ounce of the glycerins 
ia to ho added, and the nhole wull shalcen in a bottle. 
Neit, very gradually pour in the acid glycerine, frequently 
Bhaking the bottle during admixture. Test the mixture 
with blue litmus-paper, and if not of a very decidedly acid 
reaction, a few more drops of acid may he added to the 
remainder of the glycerine and mixed as before. Laatly, 
mix the alcohol and water very gradually, shaking the botUa 
Ihoronghly after adding each successive portion till the 
whole is mixed. This fluid may be kept ready pieparedi 
and iujeotioDs made very rapidly with it. 

33. The method of mating injections with these colonra 
ia the same as with the gelatine mixtures before described, 
except that no heat is required, and consequently most of 
the trouble removed. The bottle of the diiid must be well 
shaken immediately before use ; and when the object has 
been injected, we mnst allow it to remain in a cool pli 
a, few hours before cutting it. Thin sections of the snbjeat 
may be cut with Yalentin'a knife, as before described, and 

' When, however, It is desirable to out very thin aeotions of Iht 

g;etatiTie — gelntiDe ODO part to water ei^ht parts. But the wariu ^umv 
and mode of riroceediuf- which are used nitb the «zo Bolutions befoM 
deaeribed nil] be uecBBsarj iit tbie oase also. 


B very beantifnl transparent objects. Some of the finer 
tissaes, also, are Bhowa much better by tbiE mode of in- 
jection than by tbe opaqae, and ara easily mounted bj 
nashing in clean water wben first separateJ, and fioating 
Dpon a slide, where they mast be allowed to dry thoronghlj. 
They may then he immediately monnted in balsam, or kept 
' 1 ^e dry state until it is convenient to finish them ; bat 

I many cases this kei?ping, if too mach prolonged, will 
injure the object. If it is desired to transfier the eectioD to 
another slide, it will be necessary to wet it thoroughly with 
water by the aid of a oamel-bair pencil, and then gently 
Htiip it off with the forceps. When it is wished to preserve 
injected subjects in masses, it must be done by immersion 
in spirit, and the sections may be cut at leisure. Most of 
these transparent objects may be mounted in Canada 
' alsam i bnt some recommend glycerine or glycerine jelly, 

s allowing the use of a higher power in their examination, 
and preserving them in a more natural form. 

34. A few snbjects may be noticed which are very beauti- 
ful when injected, and amongst these are the eyes of many 
lals. They mnst be injected by the artery in the back 
part, and when the blue transparent liquid is employed, 
nothing can e*:ceed the delicate beauty displayed by some 
of the membrane. It mast be dissected with care, but well 
repays us far the tronble, Water-newts and frogs are not 
diEGcalt subjects, and in their skin and other parts are many 
interesting objects. Amongst the commoner animals — rats, 
rabbits, cats, &c.— almost endless employment may be 
found, making use either of portions or the whole animal at 
once. The intestines of many of these are very beantiful. 
We mast divide them with a pair of scissors along the tube, 
snd cleanse them from the contents ; the specimen may 
then be laid upon a qlide, and any remaining impurity 
removed by a camel-hair pencil and water. When dried it 
nay be mounted in balsam, and having been injected with 
the transparent blue, its minnte beauty ia shown most per- 
fectly. In injecting a sheep's foot, which is a good object. 


the liquid Bhouid be forced into it ontil a sliglit panng of 
the boot shona tbe coloar id the fine chaDO^ there, 
Perhaps one of the most beantifnl and iutcrefiting objects is 
the akin or section of a cat's tongue. On eiaminstion ws 
Bhall readi); learn tbe reason wb; ne feel such a 
when ne aKon the cat lo applj her tongne to oar basdo. 
Id appearance we ahatl be almost readj to eaj that there i>. 
no little resemblaDce in tbe arrangement betwiit this tongaS' 
and those of the mollDsce atread; described. The liver of k 
rabbit or anj other animal is an easy and beautifa! objeot 
for injection. Sections made with Yalentin's kaife, and. 
mounted in balsam, are not at all difficult, and worth donbia 
the time thej occupy. 

35. When tbe lungs of email animals are injected, the 
fioest £nid must be nsed, as some of tbe capillar' 
small that it is not an easy matter to fill them properlj, 
And before entering upon these subjects, a certain pro- 
ficiency in the mode of using the syringe, &c., ahoold be 
obtained by practiatng npoo simpler parte. 

3(). No subjects are more difficalt to inject than fisfaj. 
owing to the extreme Boftneas of their tiaaues. Mr. Hogg 
recommends the tail of the fish to be cut off, and the pips 
to be pat into tbe divided vessel which lies jast beneath Uie 
apinal colnran ; by which method beautiful injections maj 
be made. The gilla, however, are the moat interesting part 
as microaoopio objects. 

37. These inatructiona may seem very imperfect to those- 
who have bad much experience in tbia brajicb ; bat thiiy< 
will rememljei- that their own knowledge was not gained 
from any written descriptions, but was forced npon them 
by frequent failures, some of which probably were very dis- 
heartening. As I before stated, it is very difScnlt (^ not 
impossible) to accomplish much without soroe knowledge of 

38. I may here mention that tbe transparent injeotions 
Bent over from tbe Continent are beautifully executed by- 
Hyrtl of Vienna (who atates that the iojectei flnid is 

OF Micaoscopic OBJECTS, lU; 

posed of gelatine and canoine), Dr. Oscliatz of Berlin, 
the Microscopic Inatitnte of Wabern, Schafier and Co. of 
Magdeburg, and others. Some of these will bear eiamiaing 
with a high power, A friend informa me that he measnred 
ft vessp.l in a rat's tongue by Hjrtl, which was l-(200th 
of an inch in diameter, and had a clear outline with quarter- 
inch objective. He baa also made many experiments with 
the same materials, bnt has aa yet failed in producing 
perfectly diatinot outlines, there being a tendency of the 
colouring matter (magenta, carmine, &c.) to diffuse itself 
thlMUgh the coats of the vessels into the snrronnding tissues, 
although he has varied the pressure from half a pound to 
Biity poan^s. He believes the vessels are first washed out 
(injected with warm water and pressure applied), then some 
fluid introduced, probably solatioo of tannin, which renders 
the arteries imperviona to the coloured fluid afterwards in- 

39. He finds that after washing oat the vessels as above, 
the injecting fluid is much more easily introduced. He liaa 
used a strong solution of gallic acid previonslf to injecting 
with the colooring matter (ia one experiment only}, and the 
result was satisfactory. He puts the query, — Might aot 
carbolia acid have a similar eSect P He has often used it 
with injections to preserve the specimens, but not in saf- 
ficient quantity to act in the way indicated above, 

Binoe writing the above, Mr. J, G, Dale, P.CS,, and I 
have made namerons experiments with carmine injection, 
and have at length been favoured with what we deem 
anooess. Some of the vessels in a kitten lately injected do 
not exceed l-'2000th of an inch in diameter, and present a 
clear outline with one-fifth objective. There is no extra- 
vasation, neither does the colouring matter show any grain 
except when a very high power is employed. The following 
r process ; — 

raEFiEATios J 

Take leO grains best carmine. 

i fluid ounce of ammonia, commercial etrengtlii 

viz., 0'92, or 15° ammonia meter. 
3 or 4 onnces distilled water. 

Pot tbese into a. small flask, and allow them to digest with- 
oat beat from tweoty-fonr to thirtj-si: boars, or nntil tlie 
carmine is dissolved. Then take a Wincheat«r qaart bottlt 
and with a diamond mark the spot to which Btiteen onnceR 
of water eitend. The colonred aolntion must be filtered 
into the bottle, and to this pore water should be added 
until the whole is equal to sixteen ounces. 

Dissolve tiUO grains potash alam in ten floid 
water, and add to this, nnder constant boiling, a solution of 
carbonate of soda nntil a slight permanent precipitate is 
produced. Filter and add water up to sixteen onnces. Boil 
and add the solution to the cold ammoniacal solution of 
carmine in the Winchester qaart, and shake vigoronslj for 
a few minntes. A drop of this placed apon white fitteriog- 
paper should show no coloared ring. If much colour is in 
Eolation the whole must be rejected, because, although 
it is possible to precipitate all the colouring matter by 
the addition of ammonia or alnm, it is not well to do 
so, as tbe physical condition of the precipitate is therebj 

Sappoaing the precipitation to be complete, or yery 
nearly so, shake vigoroualj for at least half an hoar, and 
allow it to stand until qaite cold. The shaking mnst then 
be renewed for some time, and the bottle filled up with pure 

After allowing the precipitate to settle a day, draw off 
the clear supernatant fluid with a sjphon, Bepeat the 
washing nnlil the clear liquid gives little or no precipitate 
witb chloride of barium. So much water mast ha left. 
with the colour at last tbat it ehall measure forty flaid 

Of MicKOScopic OBJECTS. 193 

For tbe isjeotiog flnid, talie 24 onnces of the coloured 
liqaid thae prepared, and three oaacea of good gektiDe. 
Allow these to remain together twelve hours, and then 
disBolve bj the heat of a water-bath ; after which it ehould 
be ttrained through fine muslin. 

Ab this injecting fluid cautainH gelatine, the hot water, 
and other contrivanceH mentioned in a former part of the 
chapter, will be Deceasar; here also, bat no pecoliar treat- 
ment will be required. 

6 writing the above concerning carmine injection, I 
hare had the miefortune to lose mj friend Mr. Dale, but not 
before we made scores of experiments together, with this 
formula. Oor experience, I may say without vanity, joati- 
' 1 declaring that a good operator can get resolta 
aqoal t^i any that he will receive from the Continent, as far as 
coloDT and dietinctnesH are concerned. The colour, being 
thorongbly precipitated, cannot stain the tissues, and the 
conrae is thns clear and well deSned. If the object is small, 
■■ "s well to use the mixture with 25 or 30 ounces of water 
instead of 40 ; but, with this exception, I know of nothing 
that needs alteration. I have, time after time, measured 
Teasels thoroughly filled with good colour — especially 
amongst fatty portions, — and found them betwixt l-3000(Ji 
Hud l-400Oth of an inch. As some young students might 
" Give me an account of something done with it," I will 
endeavour to describe my nse of part of a horse's leg. My 
frieod Mr. Hepworth wrote to me that he had a horse's leg, 
and should be glad if I would come over with sufficient car- 
mine t4> inject it. I tooh three pints of solotion, and may 
here mention that, with a very slight loss indeed, all this 
liquid was thrown into our subject. The leg was cut off 
just beneath the knee, and before using it we allowed it to 
in water about 80° or 90° Fahrenheit two or three 
md then introduced onr syringe into an artery at 
the top. As I have no faith in any mechanioal contrivance. 


I nfied the comnion BjriDge, and Glled the leg with t 
liqaid. We then placed it in cold water, and allowed it t< 
remain nntil the next morning. 

The first work was to remove a piece of the Btin, ai 
take Beutions of it hy the aid of a Yalentio's knife. Thttl 
arteries were iihown beantifullj -, bat the most attractiTS 
part was where the growth of the hair was laid open before . 
as. Each hair exacll; resembled a common onion, whil; 
every bolb was snrronnded bj a perfect network of arteriet 
and where any bnlb had been torn oat by accident, iheu 
was left a niinnte bird'e-nest of them, clearly showing boi 
they bad been intertwined aroood some lo»t friend. Dif< 
ferent sections of the majcolar portions showed every pbaa 
of arterial distribution, with some eiqnisitely minate veseeb 
in parts. I then took an artery and cut cross sec 
wbich the carmine portions were as closely interwoven ■> 
wickerwork. I also, with a pair of scissors, laid open k 
length of the artery, and mounted it, together with a eras 
section. In the same way I Deed the Teins. Many of tfa 
nerves we took out, and, after cleauiDg carefully with knin 
and small brushes where necessary, mounted them wift 
the attendant arteries around them. But as we approacba' 
the hoof, double interest was given us. The skin with itahan 
jnst above the hoof plainly showed the change taking plae%' 
and sections of the hoof gave beantifol specimeDS of who* 
oircntatiou was gradually stayed by the growth of hardor 
substance. Here, too, we reached the Umiofe, or tiM 
plates (somewhat resembling the gilla of certain 
the exact nse of which, we have no space to discnss — mai 
these were readily removed by the aid of scisi 
knife. In these the vessels are minutely and eiqunU^ 

These are a few of the beauties which tbia injutil 
kfforded me. My friend Mr. Hepworth and I worked li 
gether at this aobji^t for a week or two, and pw~ * ** 
knowledge wbicb he gained from it waa cammaniMted I 


the microscopic world in tlie fifth volume of their Joarnal, 
where the illnstrations are beautifully printed. We took 
about 1,000 slides from this leg, but could easily have taken 
a specimen for every microscopist in the country. What 
few slides I now have are mostly mounted in balsam, and 
are quite as good in colour and every way as beautiful as 
on the day they were mounted. 


rmn-AUTKn axd 


It mnat be evident to all readers that there a 
objects of intereet to the microicopigt which caonot b 
properly placed amongst any of the faremeotioned cIb£ 
bat moat not be omitted in such a gnide as this 
to be. Of these may be mentioned the circulation of U 
blood in varioas animals, the rotary motion of the Soil 
in tnacy plaats, the beat means of taking minate phoiB 
tograpba, &a. &a. 

Perhaps the most interesting of these objects ia 
lation of the blood through the finer TeBsels of var 
of animats nsed for these parposos, which parte, it ia evidenta 
most be very tranaparent to afford a perfect view of thi 
phenomenon. The web of the frog'a foot is very freqneDtHIJ 
employed, hot requires a certain arrangement, which n 
now describe. A piece of thin wood (Dr. Carpenter r 
mends cork) is taken, about eight inches long and thraij 
wide ; about an inch from one end ia cat a hole, half CB 
th red-quarters of an inch in diameter. The body of ti 
frog ia then placed in a wet bag, or wrapped in t 
whilst the hind foot projecta ; tlic whole is then laid u 
tbe piece of wood, so that the foot, which ia left free, may b 
oxteuded over the hole. Tbs web moat then be spread ona 
Kod secured, either by loops of thread fastened to lite b 
and attached to small pins placed around the hole in the < 
or the pins may be inserted into the wood — Ihrongh t 
ireb. A few bands of tape mnat be passed round t 
body, the Ivg, and the wood, to prevent any diaarrangemi 
nriHJDg from the struggles of the aDtmal. Care ronst II 

ECTS. 19? 

I taken that the tape be not too tight, else the circulation will 
be verj slaw or altogether atopped. The wood rnust now be 
fixed npoD the stage, with the aperture under the object- 
glass : this is Bometimea done bj Bimplj binding it, or a 
Hpring is Sued ao as to aucomplisk the same object without 
inch trouble. With a half-inch power the blood may 
be seen to flow very distinctly. The frog may be used for 
hours if care be taken to prevent the web from becoming 
dry, by wetting it with a little water from time to time. 
The piece of wood or cork upon which the frog is laid is 
often made to give place to the " frog-platea," supplied by 
lus. These are made of brass, somewhat resembling 
iece of wood above recommended, but each maker's 
pattern differs, according to hia own taste. 

The tongue of the frog is also eometimea nsed for the 
purpose of showing the circalation of the blood, which is 
done io the following manner ; — The body is wrapped with 
ealieo, and made faat to the plate as before, ooly the inouth 
of the frog is brought to the opeDing. The tongue is then 
gently drawn out of the mouth and pinned down over the 
aperture, when the circulation will be well shown. But, as 
Dr. Carpenter obaerveB, the cruelty of this mode of treat- 
ment is BO repulsive tbat it is unjuatiflable. 

Tadpoles of the frog (which, of eoarae, are only obtainable 
a their season) are good subjects for showing the circula- 
tion of the blood. They are best suited for the microscope 
when about one inch long. The tadpoles of the newt and 
toad also are equally suitable. They may be placed in a 
very shallow glass trough with a little water, and a narrow 
band of linen bound lightly round in some part not required 
I, to keep them from moving ; or they may 
be laid upon a glass plate with a drop or two of water, and 
a thin glass covering lightly bouud upon it. Dr. Carpenter, 
however, places them hrat in cold water, gradaally adding 
1 until the whole becomes about 100", when the tadpole 
lies rigid, whilst the circulation is etiU maintained. I 
have not, howeTsr, fouud this neoeaaary, the thin glaea ao- 

complisUog all that is desired. The tail is generally tl 
nofli tracBporeiit, and abowa the circalatian be»t ; but ' 
some of the newt larfte the blood may be traced down 
the lery eitTemitiea jf thej are not loo old. Mr. Whitne 
places tbe tadpole upon ita back, bj which meaos the bei 
and other internal arrangements maj be seen. 

AmoDgflt fishes also maj be foaud enbjecta for the sa 
pnrpose, but they seldom fnniish socb good examplea 
thoee before mentioDed, becanse the blood-vosBels are i 
nearlj so ahnndaot as in the foot of the frog, &a. 1 
aticklebaek ia, however, procorable almost in any pli 
daring the summer nionthg, and maj be laid in a shalloi 
trough, looael; boond down as the tadpole. The tail 
be covered with a piece of thin glass to prevent him cnrlinj 
it to the objcot-glttSB. The power needed for this will ~ 
abont the same as with the other sobjects ; tjz., a, half 
a qnarter-iDch object-glass. 

It is Dot absolntely necessary to go to reptiles or fisi 
for this corious sight, as some other animals serve Ti 
well. In the wings of the common hat may be found 
good sobject. Tbese mast be slretohed ont on somethi 
resembling tbe frog-plate before described, when those pal 
near to the bones will show the InrgeH vessels very cli 
The ear of a yoocg moose is an illustration of the 
phenomraon, but it ia very dtl&cnlt to fix it in a 
position, as these animals are so very timid aod restless. 

Amongst insects also the circulation may be seen 
placing them in the cage, or live-box, ho as to keep thi 
still, but not to injure them by too much pressure, 
certain larvaj it ia particularly well shown, aa in those of t 
day-Hj and plumed goat ; but in some of these the blood 
almost colourless. In the wings also of many insects thii 
circulatioo is well seen, as in those of the common housefly J. 
but as these parts become dry in a few daya, the aubji 
shoold not be more than tnenty-four hoiiTs old, 

Somewhat spproiimating to the fore mentioned pheni 
menon, is the rotation (or cyclosis) of .fluid in the cella. 

or MiOBOScoric OBrecis. 

as it IB nsnally termed, the ciradattoii of the sfip, of plants. 
Thia is ahoiTD in certain vegetable growths as a. constaat 
Btreain of thiuk fiuiJ, wherein amall globules are seen ; 
which atream flowa round the individual cells, or up the 
leaf, tarning at the extremitj, and down again by a different 
bnt parallel chanuel. There ia little or no difficultj in 
ahowing this in many plants ; bat some, of coarse, 
better than others, and require a different treatment; we 
will, therefore, notice a few of these. Perhaps the best of 
all ia the Vailistieria a-piralts, which is an aquatic plant, 
frequently grown in, hat not really belonging to, this 
ooantry. As it aomewhat reaemhiea grass, the leaf is not 
□Bed in its natural state, but a thin section cat lengthwise 
with a razor or other sharp inatrumenti thia section, how- 
ever, is moch better when the outer surface has been first 
remoTed. It should then he laid upon a slide with a drop 
or two of water, and covered with a piece of thin glass. 
OfteOi the cutting of the section aeems to be such a ahock to 
the leaf that no motion is visible for awhile, bat in a short 
time the warmth of an ordinary sitting-room will revive it, 
and with a quarter-inch object-elasa the ourrents will be 
rendered beautifully distinct. Where the stream is nn- 
naaally obstinate, the warmth may ba slightly increased, bat 
too high a heat destroys the movement altogether, In the 
Bummer, any of the leaves show this circulation very 
well) but in the winter, the slightly yellow ones are said to 
be the best. 

The Tallisneria requires to be cut in sections to ahow 
thia circulation ; but there are many plants of which it ia 
bat necessary to take a fragment and lay it upon the slide. 
The Av-ftcharie ahhwateum, ia one of these : it grows ia 
water, having three leaves round the stem, then a bare por- 
tion, again another three leaves, and so on. One of these 
leaves must be plucked close to the stem, and laid upon a 
alide with a drop of water. Thin glass should be placed 
upon it, and along the mid-rib of the leaves the circulation 
may be seen most beautifully when a good specimea has 

200 paeriiuTioN a 

been chosen ; tot it reqaires rather more power than t 
Vallisneria. This plant ia very comnion in many parte 
the conntry, a S'eat number of our ponda and atreame b ' 
literally choked np by it. In the Clmra vvlgnris and two O 
three of the Nitcllie, &c., this phennmeaon may also be n 
with no preparation except plucking a part from the at 
and laying it npon a slide, as with the Anacharis, In qbi 
the Frog-bit, the onter part of the yonnj? leaf-bada most I) 
taken to obtain the beat specimeng for this purpose; bati 
section of the stem will also ahow the circulation, thongh ni 
so well. Tbe plants before meutioned are all aqnatic, b 
the same movemeut of the globulea has been observed i) 
several kinds of land plants ; as in the hairs npon the 1( 
stalks of the common groundsel ; but these do not show I 
80 well, nor are they so easily managed aa the preceding. 

Many microscopista who are not fortonate enough to i 
in the neighbourhood of these plants (indeed the ValUsnen* 
is a foreign one) grow tfaem in jara ; BO a few remarks as 
tbe treatment they require will not be out of place. T 
Vallianeria requirea a temperature not lower than 55° 
60°, and even a higher degree than this renders its growti 
qnicker; and no great change maat take place : the mo( 
equable the temperature the more healthy will the plant b9 
A glass jar should be taken, having an inch or two of m 
at the bottom, which must be pressed down closely, and tl 
plant must be aet in this. Water must then be gent^ 
ponred in, so as not to diatitrb the mould. As this plat 
flourishes best when the water is frequently change^ 
Mr. Qaekett recommends that the jar should be ooaasianafl] 
placed under a tap of water, and a very gentle b( 
allowed to fall into it for several hours, by which i 
innch of the confervoid growth will be removed and tbi 
plant invigorated. The Anacharis may be i 
earth like tbe Yallisneria, but a small detached piece may b 
thrown into the jar of water and there Itft nntil want«d 
For months the circulation will bewell shown by it, and it w3 
probably grow and increase. It is also very healthy ii 


1-door aquariam. It is reoommended that the jara ia 
which the planta of Chara are grown shoald be moved alioafc 
BS little as poseible, as the long toota are very tender, and 
will not hear agitation. 

An ohject which ia interesting to the microacopist, as 
well aa the nnacientiSa observer, is the growth o( seeds, as it 
ia often erroneoualj termed. A ahaving of the outside of 
the seed ia taken and laid upon the glasa slide ; a thin 
glass cover is then placed upon it, and a drop of water 
applied to its edge. The water will gradually flow nnder 
the glass and reach the section of the seed, wben transparent 
fibres will appear to epring ont and " grow " for some 
roioates. This, however, ia produced bj the unfolding of a 
spiral formation in the cells, and, therefore, haa really no 
aimilaiity to the true growth. The seeds of the Salviaa, 
Gollomia^, Senecio, Buellia, &c., are well snited for the 
displaj of this curioaa sigbt. 

To wateh the development of the spores of ferns, and the 
fertilization and produota, Dr. Carpenter recommends the 
following mode of proceeding: — "Let a frond of a fern, 
whose frnctilication is matnre, be laid upon a piece of fine 
paper, with its spore-bearing- surface downwards ; in the 
course of a day or two this paper will be found to be covered 
with a very fioo brownish duat, which consiata of the dis- 
charged spores. This must be carefully collected, and 
should be spread npon the aurface of a smoothed fragment 
of porous sacdetone ; the stone being placed in a aaacer, 
the bottom of which is covered with water, and a glass 
tnmbler being inverted over it, the reqniaite supply of 
moiatnre ia inaured, and the sporea will germinate luxuriantly. 
Some of the prothallia soon advance beyond the rest; and 
at the time when the advanced ones have long ceased to 
produce antheridia, and bear abundance of archegonia, those 
which have remained behind in their growth are beginning 
to be covered with antheridia. If the crop be now Icept 
with little moisture for several weeks and then suddenly 
watered, a large namber of antheridia and archegonia 

nUiie «ti«t to tiN 7««>g ■ 
■■■iii hf thm ipoiH «f Aa EqMta (or 
Iktf an aAca iiHni) TkM *■; W abUiMd by ai 
Ifce U^MT perlioa eftW rf— wWm tW spores sre i 

TWr «B Uca bn ia» mmD Ami, ud maj b« ] 
rader tke ^otweope. The iporca are tiua a 
of » ■ommrbat fatwi-db^wd nMs witli bonds niher iiti 
tneatclj ewted aroand it. A» 0107 dry, tLese I 
expand, and ar« aeen to bs four lines at right angles, *■ 
the enda clobbcd, as it majr be called. If, whilst watohingl 
iixtto, the spores are breathed apon, theae bands im mediately I 
retain to their funner state, and are closely corled atound I 
the apore ; bat as tbey gradaallj drj, again eipand. This f 
eiperimenl may be repeat^ many times, and is a. very I 
ioteresting one. I 

The preceding are the priocipal objects which could Dot 1 
poaeitily be included in any of tbe former chaptera, bat I 
noald have left a most interesting branch untouched had HM 
been neglected. There is another subject, also which should I 
not be pasaed by ; via., the production of minnte picturefl I 
wbich serve as objects for microscopic ei:amiDBtioQ. 
mny here mention that as tbia manual is simply I 
uiiublo the student to prepare and mount his objeote, the 1 

OF uicEoscortc osjEcis. SOS 

photography of magnified objects Las e?identlj do place 

Few alideB canaed so mnch astonishment aa those minnte 
photographs when first exhibited ; small epota were seen to 
contain large pictnreB, and a page of printed matter was 
compressed into the one-hondredth part of a aqaare inch. 
It would be imposaible in this place to gi?e the inquirer 
any inatrnctioa in the manipulation of f>hotography, ao it 
mast be assumed that he already knows ibis. 

We will first consider the process performed bj artificial 
light. The collodion employed in photographing generally 
shows aa mach stracture when nagoified as is found in 
linen of looderate textore ; bnt this is not always tbe case, 
as some samples bear mach enlargement without any of 
this appearance. It is evident that a atructnre so coarse 
would make it entirely nnfit for these minute pictnreti, aa 
all the small markings would be destroyed, or so interfered 
with, that no great enlargement would be practicable. To 
obtain almost structnreleas collodion is not an easy matter, 
and a clever practitioner in this branch of photography 
states that he knows of no method to accomplish this with 
certainty, but he himself tries different samples nntil he 
falls upon a suitable one, wbiuh he then lays aside for this 
object. A beneficial effect is often derived from keeping the 
collodion awhile, hut this is not always the case. The slides 
should be chosen of an equal thiclness, so that vhen 
focuBsed upon one, no re -adjustment may be necessary for 
the others. The glass ahotild, of course, be free from any 
TOughneBB, scratches, or other imperfections, and of Tery 
good quality and colour. 

The microscope must be placed in a horizontal position, 
and the eye-piece removed, the stage having a small clip 
npon it to keep the prepared plate in position. The nega- 
tive mnst be supported at a distance from that end of the 
microscope tube from which the eye-piece was withdrawn. 
This distance will, of course, vary according to the relative 
sizes of the negative and desired picture. With an inch 

204 vaePABiTios asd stonsTiso 

(ilijuct-giMB, wbioh is of averj conventeDt fooDEi, it will vaij 
unnall; betniit ODe and foar feet. The negative most bt 
lighted by an argaod gas-burner or oamphine-larap, and the 
rajB rendered aa parallel aa possible by a large plaoo-con»( 
lane placed betwiit the light and the negative. Iti«ii< 
easy to arrange the apparatna ao as to get the light un 
/ifr-ni ; but a little practioe will soon obviate thia difficnlty. 
Ordinary groQad-glaae is too coaraeiy grained to focns npoa, 
aa the magnifying power used to examine the minate reflee^ 
tion most be conBiderable. One of the elides must therefore 
be coated with collodion, aabmitted to the ailver-bath, oi 
ahuT waahing with water, allowed to dry. Upon thia insjr 
be foouaaed the reflected image, and its minateceaa examined 
with a powerful hand-magoifier, or another microBoopi 
placed behind in a horizontal position. Whea the ntmiMt 
eharpneaa of definition is obtained, it is naaallj necessary t( 
remove the plate a little distance from the object-glass, M 
those for the microBoope are slightly over-corrected, so that 
the chemical raya which aaeomplish the photography w 
beyond the visual ones. The exact distance required to 
give a piotnre to show the greatest diatinctness cannot bs 
given by rale ; but eiperimeata mnst be made at first, and' 
it will always be the same with the object-glass which w 
have tested. 

The plat« may now be prepared as in ordinary phot»-L 
grapby, and placed upon the stage whilst the li^t a 
•haded. When all is ready, the shade is removed and lkl| 
process allowed to go on, nanally for thirty or forty Moondi 
bat no certain rule can be given as t« the required time, ai 
acconnt of the variety of coltodionR, lamps, and paweni N 
It may be here mentioned, that it is well to c 
little frame to receive the prepared plat«, as tl 
aolntion is liable to get npion the microscope-si 
to say the least, disfigare it. When the e 
oontioned safficiently long, the pictnre may be < 
any of the onlinary methods, bat some of the 
tions have been brought ont by the aid of pyro 


oitric acid solution, nitli tbe addition of a little alcoliol. 
The filing ta&y be effected by a strong solation of bjpo- 
snlphite of soda, and the picture should then be very well 
washed with pure water. When drj, the photograph must 
be monnted nith Canada balaam, in the same manner as 
any ordinary object; bat great heat moBt not be Dsed, or 
the picture may bo injured. 

When ordinary daylight is employed for this purpose, a 
dart slide will be reqnired for the prepared plats, in the 
Hame way as for photographing landscapes, &o. These 
dark slides are generally made by each indiTidual to suit 
hia particular arrangementa of negatives ; but it may 
ba here recommended that the operator shonld always 
focus in the same slide which he is about to use, as so 
small a dli^erence in distance lies betnlxt perfection and 

For an ordinary student, perhaps the preceding method is 
that which is the most readily used, and consequently the 
most generally available; but almost every one baa a dif. 
fereut arrangement of microscope, by which he procures 
these minute pictures. !U!r. Shadbolt (one of our most 
BuocBasfa! photographers) gives the following iastructions: — 
"Haviug removed the upper stage-plate of a large oom- 
pound microscope, I replace it with one of wood, supplied 
with guide-pins of silver wire, in order to admit of its SDp- 
portiug a slip of glass coated with collodion, and excited in 
the nitrate of silver bath in the uauat way. If the ordi- 
nary brass stage-plate were left undisturbed, it is obvions 
that it and the excited slip of glass wonld be mutually 

" The microscope is now to be placed in a horizontal 
position, the objective, intended to produce the picture, 
made to occupy the place nsoally £Oud by the achromatic 
condenser on the suh-etoge of the microscope, while another 
objective is screwed into the lower end of the body of the 
instrument, which is used not only to focus with, but^also 
to make the requisite allowance for actinic variation. 

■ MgktiTe intotded to be redaced is tlioi Kirai)]^ 
rertkallj, «iUi its centre in tbe am of the mirroec^pie 
bodj, *t k dutuice from two to foar fiwt ham the lower* 
a b ject g l—», and wila a coDTCDieDt tcreea of cftrd, wood, of 
■per, to cot dff any eitr&neons light that woo" 
e pati bejond the limits of the pictare- 
nuU cam phine- lamp ia emplojed for the parpoae 
minating the negatiTe. hariiig a good baii's-eye lens 
■ eondcuKT, ao arranged with its flat side next the lamp 
that the refracted rays shall just fill the whole of a donbla 
convex lens of aboat >ii iocbes ia diameter, the latter b 
pla<Kd in HDch a position as to refract tbe rajs of light 
p«nllel direction upon the negative. Bj this arrangement 
tbe tndCt-eye lent of aboat two inches and a half in 
diameter appear* as the source of the light instead of ths 
small flame of the lamp. 

" By nsing a bat's-wing gas-bnmer of a good aize, a »ui^ 
lens, instead of the two, may be BO placed as to gifo thS' 
ueeesaary nniformity of illamioatioa." 

This arrangement requires the same care in working aa 
that before mentioned, the pictares beiog produced, de- 
Teloped, and fixed by the same treatment. 

It is certain that almost every manipnlutor malces some 
email changes in the method of prodocing these minute pio- 
tnrea ; bnt the roles given, thoagh far from new, are 
Bofficieot for all pnrposes ; and I may say with truth, that 
those which I procured when these wonders were quite new, 
are folly eqnal in every respect to the beat usually met with, 
at the present time. 

With these inatrnctiouB I shall close my Handbook, as I 
heliere that nearly every branch of tbe Preparation and 
Mounting of Microscopio Ohjects has been treated of. Hot 
that the beginner can expect that ho has only to read this 
to be able to mount everything ; hot that there are difficul- 
ties from wbicli he may be freed by instruction, when other- 
wise he would have been compelled to learn by failure alone. 
I may here, however, repeat advice before given,- 


tbat, when practicable, it is a good thing to mount each 
object by two or more diflferent methods, as very frequently 
one feature is best shown dry, another in liquid, and a third 
in balsam. Secondly, let no failures discourage you in 
following up what will assuredly one day become a source of 
great pleasure, and render your daily constitutional walk, 
which is often dull in the extreme, very delightful, as it will 
afford you some new wonder in every hedge-row. And, 
lastly, let the mounting be studied thoroughly, scarcely any 
part of microscopie science being more worthy of thought 
than this, since it will so far contribute to the enjoyment 
or instruction of others, as to preserve for their examination, 
objects which have already ministered to your own, but 
which may yet be so perishable as to be speedily lost unless 
some one of the many processes described in this manual be 
employed for their preservation. 







Acid, acetic 5 

Acid, carbolic ....^ 127 

Acid, chlorhyd 5 

Acid, hippuric 114 

Acid, hydrofluoric 19 

Acid, hyperosmic 9 

Acid, nitaric 5, 61, 62 

Acid, nitric, with chlorate 

ofpotash 6 

Acid, oxalic 6 

Acid, phosphoric 5 

Acid, sulphuric 5, 11 

Acid, tannic 5 

Agents, "differentiating"... 5 

Agents, hardening 9 

Agents, softening 13 

Agents, staining 7 

Air-bubbles 42 

Ait-bubbles, to expel 91 

Albumin 16 

Alcohol 5, 6. 9,17 

Algse and desraids, to pre- 
serve 127 

Algae, to presenre 125 

Ammonia 6 

Ammonia, molybdate of 7 

Ammonia, oxalurate of 112 

AmmonisB, liquor 14, 67 

Anatomical roecimens, Bru- 
netti's mode of preparing 164 

Aniline colours 7 

Animal tissues, dissection of 163 

Anise, oil of 7 

Antenna 107, 137 

Antennsd, to bleach 107 

Asphaltum 45, 49 



Balsam and Chloroform 44 

Balsam, Canada 7 

Baiyta water 6 

Bath for injections 177 

Bath, hot- water, cheap 93 

Beaker glasses 65 

Benzole 17, 19 

Benzole — Benzine 75 

Berg-mehl 72 

Blights 87 

Blood-discs 83 

Blood-stains, to detect 84 

Blue, Prussian 8 

Boiling 11 

Bone, chips of, stained 149 

Bone, sections of 148 

Bones, fossil, sections of ... 150 

Bones, softened 15 

Bottle-washing 76 

Brain and spinal cord, sec- 
tions of 166 

Breeding-cage for podur», 
Mclntyre's 83 


Calcareous matter, sol- 
vents of 18 

Camphor 20 

Camphor- water ... 13, 123 

Canada balsam 43 

Canada balsam and benzole 90 

Carmine solution 7 

Casein 16 

Cassia, oil of 7 

Castor oU 19, 127 




Castor oil, to mount crystals 

in 113 

Cells, built up 129 

Cells, brass 31 

Cells, of card 29 

Cells, epithelial 7 

Cells, how to fill with balsam 95 

Cells for test objects 32 

Cells, ivory 81 

Cells, leather 30 

Cells, paper 56 

Cells, pill-box 31 

Cells, Piper's 31 

Cells, tin, zinc 31 

Cells to fill 132 

Cells, wooden 29 

Cellulose in coal 144 

Cement cells 54,128 

Cement, Dr. Bastian's 129 

Cement, electrical 46 

Cement, Marion 47 

Cements 43 

Cerebral tissue 13 

Chalk, organisms in 98 

Chamber, moist 22 

Chondrin 17 

Chromic acid 9 

Circulation in Anacharis and 

VaUisneria 199 

Circulation in foot and tongue 

of frog, to see 196 

Circulation in insects 198 

Circulation in tadpoles 197 

Clips, spring 41 

Cloves, oil of 7 

Coal, cannel 144 

Coal sections 143 

Colours for injections 178 

Condenser, cheap 51 

Coniferous wood 144 

Corallines 81 

Coral sections 143 

Cornea, nerves of 169 

Covers, glass, to cut 26 

Covers, ornamental paper ... 57 

Covers, glass, to clean 28 

Covers, to gauge 27, 28 

Creosote 7 

Crystallization Ill 


Crystallization, compound... 115 

Crystals, sections of 157 

Cuticles, siliceous 121 


DA.MMA.R 44 

Dammar and benzole 20 

Dammar cement 45 

Deane's compound 125 

Decalcifying process 141 

Diamond beetle 88 

DiatomacesB 58, 60 

Diatomacese, cleansing of ... 61 
Diatomacese, collection of ... 59 
Diatoms, cleansing of by Mr. 

Eylands 63 

Diatoms in situ, to mount by 

Ry lands' method .., 1^ 

Diatoms, to bleach 65 

Diatoms, to mount 63, 67, 69 

Diatoms, to mount in Canada 

balsam 97 

Difi^urentiation, chemical ... 5 
Differentiation, mechanical 5, 7 

Digester, Papin's 15 

Disc revolver. Beck's 63 

Dissection 160 

Drying 11 

Drying tissues, Mr. Suffolk's 

• process 159 

Dyticus, foot of 109 

Dyticus, spiracles of 109 

Dyticus, wings of 109 


Earth, Bermtida 72 

Echini, spines of 142 

Eggs of insects, to preserve 137 

Equiseta, spores of 202 

Equisetum, cuticle of 120 

Electricity 21 

Elutriation 66 

Entomostraca 134 

fASBAHTS, Mr., hia medium 134 

IWthBM of birds 110 

Pert of insooU 108 

IPernt, fhiotiQiHtiini of 201 

Ttma, aeBlesof. 61 

FoniB, wares oE S5 

Rbrin IB 

File or Rubber, comadum 140 

rilter, faibe 77 

Biniriiinfr 68 

Fish, sealBB of 88 

FihIi, tails and Bus of --.,-. ^- 84 

Flint, Bootiona of 146 

Flustrn UTiculapie 119 

Foraminifera , 73 

Forarairifen, Bofitions of ... 78 
Foraminifera, to cleanse... 74, 7o 

Forceps 37 

, Fn?:{^}a, bulldog ITS 

i, ForcepB, oomprBi ' "" "" 

Foroeps, Ooode'e 

Fwuops, Page's oa 

F««ep9, Spi^ncer'a 41 

Foroeps, noodoii 38 

FtoBHing tisauBs 11 

Froe, ooraea of 8 

Froit-stones, seetioDBof. 150 

Fuohalno 8 

Fungi and moulds 87 


Gelatibe 17, 177 

Qaraninm, petsl of 80 

Gillsotfish IBS 

Oiizards 173 

Olasa-eDgraTiiig 19 

Glno 177 

OlnSjliquid 46 

Ohie, Touiive 45 

. Glycerine... 6, 7, 10, 13, 124, 137 

Glyoerine and gum IS 

Dlyoerii,B jelly V. 

. GlycBrine, refractiTO pnwei 


SnffoUc and Hifllop 1! 

Goadbj, Mr. V 

Goadby's fluid i; 

Gosdby's solution II 

Gold, ohloride of 8, 1! 

Gold, chloride of, and po- 


3uano, diatoms in 

Guano, diatoms in, by Mr. 

Eoberts ' 

Guano, spurious 


Gum-waier ■ 

Gum-water, eitra adliebiTe 


HyperosDiic acid ... 

Injeotion, blue, transparent 11 

otion, process of 1. 

ctions I 

ctioQs by double deoom- 




Injections, to mount 184 

Injections, transparent 186 

Injections, twofold 184 

Injections, various 189 

Insects, bleaching of 21 

Insects, examination of, by 

polarized light 21 

Insects, eyes of 10, 89 

Insects, internal organs of... 17 

Insects, legs and feet of 88 

Insects, muscles of 21 

Insects, scales of 81 

Insects, to moimt in balsam 104 

Insects, trachese of 92 

Inversion of objects 60 

Iodine 6 


jAPANblack 46 



Kesteven on brain and spinal 

cord 12 

Kidney, injected 166 

Knives, dissecting 37, 161 


Labelling on glass 19 

Labels 49 

Laminae, thin 15 

Lamp, Bunsen's 42 

Lamp, spirit 42 

Larv88, skins of 84 

Lathe for sections, Butter- 
worth's 144 

Leaves, cuticle of 79 

Leaves, hairy 79, 86 

Leaves, parenchyma of 17 

Leaves, sections of 154 

Lenses, immersion 23 

Lieberkuhn 89 

Light, polarized 20 


Lime-water 6 

Liver, injected ...., 166 

Lung, injected 166 


Maceration 13, 16, 162 

Mayflies 138 

Mercury bichloride 9, 11 

Mercury nitrate 17 

Metal capsules for Canada 

balsam 94 

Microscope, dissecting 160 

Microscope, Gairdner's 64 

Microscope, inverted 22 

Mosses and AlgSD «. 133 

Mosses, fructification of 85 

Mosses, to preserve 125 

Mounting, dry 62 

Mounting in Canada balsam 90 

Mouth of insects 109 

Muscle 164 

Muscular fibre 15 


Nails, softened 15 

Needles, curved 176 

Needles, dissecting 161 

Needles, use of 37 

Nerve-tissue 13, 166 

Neutral media 2 

Neutral tints 20 

Nitric acid 80 

Nummulites 17 


Oatmeal, parched U 

Objectives of wide angle ... 4 

Objects small, to take up... 36 

Oils, essential 19 

Oily and fatty matters 19 

Oily and fatty matters, sol- 
vents of 19 

Onion^ raphides of 120 



Ojtten, young 


... 8 
.... 117 


- Saw, watoh-apring 

Scales of eel 


Scales of plantfi 

SuisBorB, dissecting 



., 140 
.. 117 
,. 117 

.. lai 
r, Ifil 

.. 87 
.. 75 

PaloB) of oeresla 

... 121 

Palladium, proto-ohloride of S 


Seeds and pollen 

.. 81 

.. no 


Saads, BBCtions of. 


Sheila, pearly, seotion of 

Sheila, aections of 

Silioft, colloid 

Silica, or eilicio aoid 

Silica, yegatable 

SilicaouH matter, solifcnta 

.- 158 
.. 119 
.. 142 
-. WO 
.. 18 
.. 18 
.. 67 
of 18 


Podura, EOBles of 


... 68 

... in 

po^ .....: 

... 100 
... 135 
... Ifil 


.. 4S 

.. 17 

, 13, H 

PotaealHin, ferto-cjanide 

.. 57 

Slides, to cover and on 



Raphides for poloriscope 

.... 80 
... 120 

Bodffl, liquor 5 

Soft tissues, seotiuQS of .. 

.. 155 

Spioer, the Rev. W. W 

praBBrvativa fluid 

Spicula of sponges 

Spider, poison-glanda of. , 

Spinal cord 


Spleen, injected 

Sl>onga, BBctionB of 

Stage of microscope, hot 

.. 127 
.. 103 
,. 168 
.- ]fl5 
,. 168 
,. IKS 
.. 166 
,. 22 
.. 7 


Knga, Tulcanila 

Eings, lino SBd Un 

... 130 
... 131 
... 131 
... 131 
... 37 

Riull, SMtiODS of 




... 164 

... 113 
... 113 

-. 1S9 

'.'. 60 

Stand, Mr. Loj's 

Stand, universal 




Starches 119 

Star-fish 78 

Stomach of molluscs 1 70 

Sublimate, corrosive 17 

Sug;ar 7 

Syringe 175 

Syringe for balsam 93 

Syringe, glass 162 

Syrup 14 


Table, brass 42 

Tannic acid, or Tannin 6 

Tannin 9, 11, 17 

Teasing by needles 3 

Teeth, sections of 92, 146 

Teeth, softened 15 

Tendon 17 

Testae 18 

Thwaite's liquid 126 

Ti n tubes, collapsible 44 

Tongues of molluscs 169 

Tongues or palates of mol- 

lusca 118 

Tracheae of insects 109, 167 

Trough, dissecting 162 

Tubes, dipping 37 

Turntable, Mr. Hislop's 33 

Turntable, Dr. Matthews'... 34 
Turntable, Mr. Shadbolt's... 33 


Turpentine 7, 19 

Turpentine, spurious 91 


Valentin's knife 155, 184 

Varnish, black 48 

Varnish, caoutchouc 48 

Varnish, sealing-wax 48 

Vegetable tissues, dissection 
of 162 


Watch-qlassbs 41 

Waterrbath 22 

Wine-glasses, brc^en 42 

WhcJebone 14 

Whalebone, sections of 151 

Wood, fossil 144 

Wood, sections of 15ii 


ZiNO, chloride of 126 

Zoophytes 87 

Zoophytes, to mount 103 

Zoophytes, to preserve, by 
Dr. Bird's method 101 



An Introduction lo the Natural Histoir "f Shells, and of the Animals 
which form them. By Lovell Reeve, F.L.S. Royal Sva, 2 vols. 6a 
I Colored Flates. S^S. 


Or. Figures and Descriptions of Iht Shells of MoUusks with remnrfc»( 
I on their Affinities. Synonymy, and Geographical Disirihution. By LovEU. 
I Resvb, F.L.S. Demy 4to, in double Parts, with ]5 Colored Plates, $10, 
■ A detailed list of Monographs and Volumes published may be had. 


fa, Instructions for iheir Treparation ancl the Formation of an Herbarium 
--'-■-' md Edited by the Rev. W. W. Spicer, M.A. \Vith :i4 Illa» 
imo, cloth, price $1.50. 


r M. C. Cooke. New Edition. Greatly enlarged, and including 
it Teratologital terms. With more than 300 II lustrations. i6mo., 
lelolh, price $1.50. 


HOMAS Davies. i6rno, doth, $1.25. , 

tbor'B Esperianfe snd itml. or many of liig friends in overydepirt- 
_.. .IcManlpnIalion; and ns It Is Inlcnaod to assist the IwffluDBr as 

|a advanced stadcni, the rery rudiments of thn ar 

9ete Catalogues of works in the above departments 


4th Ave. and g3d 8t., Xew I'ork^ 






'n Illustrated Medium of Iiiletchange and Gossip fer Sludenti- 
and Lovers of Nature- 
Edited bv J. E. TAYLOR, F. G. S., 
Author of "Geological Essays," "Geological Stories," etc. 


It will be published monthly at the price of 2D cents a numberi $3,Z5 
a jear. Of the American issue the first five numbers for 1873 are now ready. 
Subscriptions can commence in Januaty ot July. Specimen numbers sent 
on receipt of 15 cents. 

The volume for 1S72, in a handsome American dress, forming a com- 
plete and attractive volume on Natural Science and History, copiously Illus- 
trated, is also ready for delivery. Price, prepaid by mall, $3.50. 
The six volumes prior 10 1871, can also be obtained. 

Price, bound in cloth, each ..... $2.50. 
Or six volumes bound in two, in half morocco, . iD.oo. 
This Magazine has achieved in England a great success, and the pub- 
lishers are assured that its republication in this country will be welcomed 
by thousands of readers, students and lovers of nature. 

The anieles are prepared by able scientists, and while put into popular 
language, are guaranteed as being exact and thorough. The illu.stralioiis aie 
copious, carefiUly drawn and handsomely printed, while ihe moderate price 
places the work within the reach of all. 

We give below some few of the English opinions of the magazine. 
"ThiB ]■ ■ very pteBsant Journal that costs bnt s triflo a montli. and fromirbieU 

intormailon. It In conducted flod contrihuti^d to by eipert natursliBtP. who are 
oheerfulconipanlonB. » all good uaturaliatB are; li^cbnfcal Fnon^b to nishe Ihe gen- 
eral reader fael iLat they are In eameft. and am not inaultlue blm by wrliing down to 
bin cumprehenslou, hnf naiuni onuoEb and direct enangh in their nconis ot Tacts, 
tlieir qusT'Ilnnliig and answering each other caDCecDlng curioaitieB of nature. Tbe 
reader wbu bqyp Tor hliDBelt their moutbly DudMt of nntea and ditcnaalona npoa 
uleaitanl potntB In natural hlatoiv snd science, Wlil pmbablT And his cuiioHlty BXdIed 
and Mb iotereBt In the world about him Ukiiig the (Otm of a tittle Elndyof soma branch 

■elf !■ eu dtllehtful and Ihe enthnsiaBm it cicile> eo oenalne and well directed, these 
enthnBlanns are conlaglDus, The fault la nnt with liicir but with the public, it tbla 
Utile nuu;azlBa be not in favor with a very lar^ circle of reideta,"— ii!r(nnfn«-. 

"It 6 a capital IdPa. Scarcely any periodical of the day on gbl to be nmra popu- 
lar; and If It answers its deslsi!, It will be more than mont a power to reilne. tu 
enlarge, and to elevate tbe mind.'"— A'onawi/oTTBi**. 
. "TFb augur great eociees for this much.wanttd montblj. It lj lUnBlraled with 
— " It wood enirravtngs."— X>m«'« Bath Jovmai. 

— variety of Inrormation It contains on tba most Interesting subjects le reall]' 

g."—XiUlemi JotiTval, 

It'Donnds with interertln); ln[ormatiDii relative to tbe varied fotmi of animal 
'"' — ' In BtiardlaiL 

"" ""'""' °"°"' """'"' ' * ' '""" "' '^'ot I'cden 



. G. P. PUTN-AM's Sons will hereafter publish for tlie Uniied Slat 
American edition of the well known English Periodical. 


An Illustrated Mtdium of Interchange and Gossip for StudenhM 

and Lovers of Nature. 

Edited by J. E. TAYLOR, F. G. S., 

Author of " Geological Essays," '■ Geological Stories." etc., etc. 

It will be published monthly at the price of 20 cents a number; (a.l 
■ year. Of the American issue the first live numbers for 1S73 are now read,. 
Subscriptions can commence in January or July. Specimen nuinbers sent 
OD receipt of 15 cents. 

The volume for 1S72, in a handsome American dress, forming a com< 
plete and attractive volume on Natural Science and History, copiously Illus- 
trated, is also ready for delivery. Price, prepaid by mail, ja.50. 
The six volumes prior to 1073, can also be obtained. 

Price, bound in cloth, each - . . . . $2.50. 
Or six volumes bound in two, in half morocco, - 10.00. 
This Magazine has achieved in England a great success, and the piil> 
lishers are assured that its republication in this country will be welcouwj 
by thousands of readers, students and lovers of nature. 

The articles are prepared by able scientists, and while put into populn 
language, are guaranteed is being exact and thorough. The lUastratians w 
copious, carefully drawn and handsomely printed, while the moderate piis 
places the work within the reach of all. 

We give below some few of the English opinions of the magad 

"Tble <> B very plearant }onma1 Ihst costs bnt a trifle a month, and from lAU 
tbe leadur who Is DO uataniliiit ought to be able to pick up a gooiJ deal or pleitB*^ 
InfonitHlIon, tt In condncted and contrlbnled to by export ustaraliBtr, wbo an 
ctaeerrulcompanlonp. aeall BO°d iiaturallau are; teehnfcal enoQeb to Diake the gen- 
eral ntader feel ibat they are In earnefl. and are not iaanltioE blm by wrlitng down to 
hl« cuiDpreheDBlon, but nainral euuauh and direct taaagbia Itielr recordt Dt brtl. 

toij and 


loathly 1)nMef of %Dtee and dlacaulons Bpan 
, ... js., p,^ji,[i(ind I1I9 cnrloritj eidied 

J — , , Bblj 

„ _ . ..Idabont him takiHg tbe tOrmofalUtle study of 

<ir Dit^BOrt or knowledge that liaB wan bin readlBatatteDtlDn. For when tbe pCudy 
telr If lU dellghll'ul aud Ibe enthUBlBBiu It exctteii «a KenulDBaud well directed, tbc 
■—'■—■ — contagioua. Tlie fault 1» not with HbbK, but with the public. If U 

.. otthe day onghllo 1)6 miirepopB. 

uiu 11 II aniwun me aeeiiu. It will be BIDre than mo^l a power to reSue, lu 

re, and to elevate tbe miod?'— A'0BO»i/)»mS*(. 

\ve an^r great euccess Ibr tliie much-wutited monlhly. It it llluatrated wllb 

lent wood enuravlng?."— A'tmf'j BaUi Journal. 

The varlBii o( Jn(ono»lion it contains on the moat Intereeting Bobjecte la roallj 

„. —kiiktmy Joiemat. 

.^/(_»600Ddewith Inlerestlng 

d beat of its kiol. 


. G. P. Putnam's Sons will hereafter publish for ilie United Sta 
American edilion of the well known English Periodical, 


An Illustrated Medium of Inlerckangt and Gosupfor StudenaM 

and Lovers of Nature. 

Edited bv J. E. TAYLOR, F. G. S.. 

Author of "Geological Essays," "GeoloEical Stories," etc., e 


It will be published monthly at the price of 3D cents a number; $2.9; 
Sfear. Of the American issue the first Gve numbers for lS73 are now ready. 

Subscriptions can commence in January or July. Specimen numbers sent 
on receipt of 15 cents. 

The volume for 1872. in a handsome American dress, forming a cnm- 
plelc and attractive volume on Natural Science and History, copiously Illus- 
trated, is also ready for delivery. Price, prepaid by mail, $2.50. 

The six volumes prior 10 1873, can also be obtained. 

Price, bound in cloth, each - . . . . $2.50. 

Or six Tolumes bound in two, in hall morocco, - 10.00. 

This Magazine has achieved in England a great success, and Ihe pub- 
lishers are assured that its republication in this country will be welcomed 
by thousands of readers, students and lovers of nature. 

The articles are prepared by able scientists, and while put into popular 
language, are guaranteed Bs being enact and thorough. The illustrations are 
copious, carefully drauii and handsomely printed, while the moderate price 
places the work within the reach of all. 

We give below some few Of the English opinions of the magazine. J 


"ThlB iB t, verj pleasant Journal that coeti bnl a trifle a month, and from wU* , 
the reader who la no naCnraUBt oneht to be alila to pick Dp a good deHl of pleasaBf 

cbearful campaaionB, a«sll good ualurallBU are: tBcbafcal pooueb to make ttie g<D- 
eraireBderreel tbattheTarelnfsmoX. lodBreDDllqeuitlnahim by wri'lng down to 
bin comprchenHlOD, bnl nainral eouatib and direct Mongh in tbeir reconlH of f&cta, 
their que-iliiiliig and aneweriuK each Dtbei eomJEsBtttt.DurloiLtlaa nf natare. Tbc 
reader who bujrp for blnueir tbelr monthl; buaM^^itsB Bnd dlHcneBiona npoa 
pleasant poliila In natural hietor; and science. wiU ^cobahli And his cariosity eicfied 
and hla Inlereat tn the world about blm taking Ibalbimor a little etudj or some branck 
or tliU Bort of knowledge that baa wou bji readteat attention. For when lbs rtady II- 
BDir I> «u HeUgbtral and Ihe enlhUBlBBm It excltef eo genuine and well directed, tnew 
enlbuBlaBm« Rio cobtagjons. Tbe fsnlt Ib not with itseir. hut with the public. It tliU 

"Ii S a capital Idea. Scarcely anj periodical of the day ooght to be morepopo- 
aud If It ani'werB its deBlirn, It wl^I ba more than moet a power to refine, to 

eular», and to eievaia the minAy—KonamformUt. 

" The rarlelv of iotonnBtlon I 

monthl;. It le illuBtt 

wood eocravings."— AVwi'i Bath jovmal. 

Tarielyof information It contains on tbe most intereBtlng Bnbjecta ia reailj 

"rAoppblleatlOn before n» la cettatalj ono ol vto tVanesl and beat of ite kind, 

■"-" '-■-■-J merit Ib the ewj aiif8ip\aE. BVl^i \n ■»i\4t'E V. vtMia of aciantiM 

^^SlndoDI&'and lOTera ot nature wUl tUi4 vMs mfteMMfi toiii>i«.\*\n'CMBi,r-