ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
599 
Preparation of Retinal Cells of Fishes.* — Prof. J. A. Ryder 
described a method which leaves but little to be desired for clearness 
and histological differentiation with sharpness of detail. Specimens 
which had been splendidly fixed and preserved were stained in toto in 
an alcoholic solution of haematoxylin, and differentiated in toto in a 
1 per cent, solution of potassium bichromate. 
Study of Spermatogenesis.f — Mr. E. Y. Wilcox describes his method 
of preparing the testes of Cicada and Caloptenus. The testes of the 
former were killed in Muller’s fluid ; those of the latter either in hot 
water, in hot or cold corrosive sublimate, or in ckrom-osmic-acetic 
mixture. Some of the testicular follicles of Cicada were stained in 
Grenadier’s alcoholic borax-carmine, others according to Bizzozero’s 
modification of Gram’s method. Good results were obtained by double 
staining with safranin and victoria-green. Crystals of the latter were 
dissolved in absolute alcohol or in clove oil. The sections were first 
stained in safranin for from 10-15 minutes ; the excess of staining was 
quickly washed off in 90 per cent, alcohol, and then a very strong 
solution of victoria-green in absolute alcohol was applied for one to two 
minutes. Excess of green was washed out with absolute alcohol. The 
Caloptenus material was all stained on the slide, and good results were 
obtained with the safranin and victoria-green method. 
Cytoplasm and achromatic nuclear parts were stained green, the 
chromosomes, nucleolus, and centrosomes red. The safranin and green 
method was the only one by which, the archoplasm was made distinct. 
If Henneguy’s method be used the safranin must not be too much 
washed out or the sharpness of outlines will be lost. It is best to wash 
out the mordant very thoroughly before using the stain, for the potassic 
permanganate makes a precipitate with the safranin which renders the 
section so muddy as to be nearly useless. The best results were obtained 
Ry the use of Heidenhain’s method, and the so-called black process 
proved more serviceable than the blue. For either process the sections 
should be very thin. They must be firmly affixed to the slide, for the 
washing is best done by a stream of tap-water allowed to run over it. 
Three washings are necessary, each of which should be thorough. 
Simple immersion in water does not do as well. 
Investigation of Mesogloea of Alcyonium digitafum.! — Mr. W. L. 
Brown on putting to himself the question whether this mesogloea contains 
nucleo-albumen, reflected that, thanks to the method recently introduced 
by Lilienfeld and Monti, the examination of this question micro- 
chemically is quite feasible. Specimens hardened in osmic acid were cut 
with a freezing microtome, then washed thoroughly and placed in a 
solution of ammonium molybdate. After being washed for a few 
seconds in a mixture of ether (9 parts) and water (1 part) they were 
put into a 20 per cent, ethereal solution of pyrogallic acid. The cells 
in such specimens were seen under the Microscope to be stained black, 
but the mesogloea was not. 
Demonstrating Tubercle Bacilli in Sputum.§ — Dr. S. Stirling 
praises Von Ketel’s method for detecting tubercle bacilli in sputum, a 
* Proc. Acad. Nat. Sci. Philad., 1895, p. 161. 
t Bull. Mus. Comp. Zool., xxvii. (1895) pp. 3-5. 
X Quart. Journ. Micr. Sci., xxxvii. (1895) p. 393. 
§ Centralbl. f. Bakteriol. u. Parasitenk., l te Abtb., xvii. (1895) pp. 874-8. 
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