ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
705 
(2) Preparing: Objects. 
Mode of Studying Gills of Lamellibranchs.* — Dr. F. Janssens 
used injections of gelatin, gum arabic, and especially nitrate of silver in 
order to study tbe blood-cavities of the gills of Lamellibranchs. Imme- 
diately after injecting a 1 or 2 per cent, solution of osmic acid distilled 
water must be introduced by the same means, and then another solution 
of nitrate of silver of half the strength. It is best to wash with water 
and not to expose the organ to the light until it has been put in 70 per 
cent, alcohol. 
Teasing was found to be of much use for the study of the epithelium ; 
a solution containing a third part of alcohol, the boric and salicylic 
acids employed with so much success by Engelmann, and very weak 
osmic acid acting for two hours all gave very interesting preparations. 
Maceration in strong carbonate of potash in the oven at 70° for several 
days was very useful in the study of the skeletal part of the gill. 
Gilson’s was found to be the best fixing method. Staining the 
sections is strongly recommended ; one point is that one is able to 
make use of various new staining reagents used in the industrial manu- 
facture of wools ; a number were tried, and one — the blue carmine 
(brevete N., Meister, Lucius, & Briining, Hochst a/M) is strongly 
recommended. Since the author used it it has been introduced into the 
laboratory at Louvain, and it has been shown that it has a special predi- 
lection for those parts of the protoplasm which undergo cuticular differ- 
entiation. It has the advantage of being a solution that can be employed 
in alcoholic solution ; it does not stain the collodion employed to fix the 
sections, if one is careful to wash in alcohol after staining. It is as 
well to add two or three drops of hydrochloric acid to every hundred 
ccm. of the reagent. 
Preparation of Early Stages of Distichopora violacea.f — Dr. S. J. 
Hickson, who has tried many stains and combinations of stains, finds that 
the best treatment is to place the sections of D. violacea, when fastened to 
the slide, in a strong solution of eosin in 90 per cent, spirit for an hour, 
then to wash in 90 per cent, spirit, and stain in weak hsematoxvlin for 
twenty minutes. This treatment gives a beautiful double stain, which 
shows the nuclei and the chromatin granules better than any preparations 
treated with carmine. 
Examination of Protozoa in Cancerous Tumours.J — Messrs. M. A. 
Buffer and H. J. Plimmer, who have confined their investigations to car- 
cinoma of the breast, report that, for fixing purposes, they have entirely 
given up alcohol alone, as the results are very uncertain. Osmic acid 
(1 per cent.) and Foa’s solution — equal parts of salinated solution of 
corrosive sublimate in • 75 per cent, salt solution, and of 5 per cent, 
solution of potassium bichromate — gave excellent results. The osmic 
acid preparations, stained with eosin and haunatoxylin, were extremely 
instructive ; those fixed with Foa’s solution stained fairly well with 
Biondi’s reagent, or with eosin and anilin-blue. Striking results have 
been obtained by using for fixation purposes the solution of chromic 
* La Cellule, ix. (1893) pp. 8-10. 
t Quart. Journ. Micr. Sci., xxxv. (1893) p. 129. 
X Journ. of Pathol, and Bacteriol., i. (1893) pp. 397 and 9. 
