1880.] 



MICKOSCOPICAL JOUKNAL. 



65 



tive in appearance. It is not a diffi- 

 cult task to mount any ordinary ob- 

 ject, but to determine beforehand 

 liow it should be mounted, that is, 

 whether dry, or in balsam, or in fluid, 

 requires judgement as well as taste. 



These articles are intended to be 

 of assistance in deciding this and si- 

 milar questions which are certain to 

 arise in the mind of the beginner, 

 as well as to instruct in the practical 

 manipulations. By following the di- 

 rections that will be given, any per- 

 son of ordinary ability will find it 

 possible to mount objects fully equal, 

 in every respect, to those which are 

 sold for seventy-five cents or a dol- 

 lar, and in very many instances far 

 superior to these. 



As far as the intrinsic value of 

 mounted objects is concerned, there 

 is no doubt that the preparations 

 made at home will be better than 

 those from the shops, for the 

 student is most likely to mount 

 such objects as he finds interesting 

 and with which he is, in some 

 degree, familiar, and he will en- 

 deavor to bring the peculiarities 

 of the object into view, even at 

 the sacrifice of its general appear- 

 ance. It is true that a large propor- 

 tion of the slides sold by the optici- 

 ans are only pretty or amusing ob- 

 jects, very attractive on the outside, 

 but of little value to the student. On 

 the other hand, many of the most 

 valuable slides in private collections 

 are dirty, besmeared with balsam, 

 marred by air-bubbles, the cement 

 spread as by a miniature white-wash 

 brush, and labelled on irregular slips 

 of paper of various colors. The pre- 

 parer of such slides will probably 

 say that they were made for "work" 

 not for "show," and that he has not 

 time to prepare what he calls, with 

 no little contempt, "show-slides" — 

 utterly oblivious to the old saying 

 that what is worth doing at all is 

 worth doing well. 



The writer is not speaking from 

 theory in this article, but from prac- 

 tice, and he asserts, in most positive 

 terms, that it is no more difficult to 

 prepare a neat slide without sacri- 

 ficing its scientific value in the 

 slightest degree, than it is to 

 prepare the same object in a 

 slovenly manner, and it requires no 

 greater expenditure of time. There- 

 fore, whatever is mounted should 

 be mounted in a neat and proper 

 manner, or else, on some future day 

 there will be a great destruction of 

 old slides, because they are unfit for 

 exhibition. 



The processes for mounting that 

 will be given in these papers are 

 those which the writer knows to be 

 good for durable preparations. 



There are many kinds of cement 

 in the market, but only a few of 

 of tliem are necessary or desirable, 

 half a dozen at the most will answer 

 all demands. The most desirable 

 cements and mounting media, and 

 the onlye necessary ones, are the 

 following : 



1. Canada Balsam. It is desirable 

 that this should be rather thick, 

 but the ordinary balsam of the drug- 

 stores is good enough. Balsam thick- 

 ens by keeping and will eventually 

 become quite hard, even brittle. Old 

 balsam is very valuable for some 

 purposes. The yellow color can be 

 almost completely destroyed, by ex- 

 posing the balsam to sunlight for 

 a long time. 



2. Canada Balsam in benzole, 

 chloroform, ether or other solvent. 

 Perhaps the kind most generally 

 useful is the benzole-balsam. To 

 prepare this, take balsam that is 

 quite hard, either very old balsam 

 or some that has been heated until it 

 is artificially hardened, and dis- 

 solve it in benzole. Make a sirupy 

 solution for a mounting medium, 

 and dilute a small portion of this 



