ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
131 
Preparing* Bone Sections.* — Dr. M. Matscliinsky, in his study of 
the matrix structure of hone, made his sections as follows : — A thin 
plate sawn off the hone is filed smooth on one side (watchmakers’ files 
are recommended) ; the smooth side is glued to a stone or glass and the 
rough side smoothed ; the translucent slice is taken off and rubhed 
between two pieces of ground glass with emery powder ; then it is 
polished with the finest hone till the surface shines. All this — a 
familiar enough process — takes, he says, about 10-15 minutes. 
The section is then placed in distilled water, then in 1 per cent, 
silver solution, and exposed to light. When a brown colour appears it 
is removed, washed in distilled water, dried in blotting-paper, and very 
carefully repolished. Another method is to leave the section in the 
silver solution in complete darkness for a couple of hours ; in this case 
the impregnation is deeper. 
Study of Reproductive Cells of Elasmobranchs.f — Mr. J. E. S. 
Moore, in his study of the spermatogenesis of Elasmobranchs, cut up 
the testes of various species into pieces about the size of half a cubic 
centimetre, and fixed them in various ways. The most successful pre- 
parations were obtained after the use of Flemming’s strong solution, 
Hermann’s fluid, osmic acid in various strengths, and corrosive sublimate, 
both with and without acetic acid. Valuable comparative material was 
obtained by treating the testes with glacial acetic acid and washing 
quickly in water, by teasing up the fresh material in acid carmine, by 
fixing in a 2 or 3 per cent, solution of formic aldehyde, by the use of 
Carnoy’s fluid, and last, but not least, by a formic acid method which he 
hit upon quite by accident. This consisted in placing small fragments 
of the living testis in a 50 per cent, solution of formic aldehyde for a 
few seconds, and then transferring directly to 50 per cent, alcohol, after 
which they were treated for sectioning in paraffin, in the usual way. By 
this means the chromosomes were in some cases rendered admirably 
distinct, but the fixing, so far as the author has yet tried it, renders the 
material difficult to stain. 
Investigation of Cerata of Dendronotus.J — Mr. J. A. Clubb allowed 
specimens of Dendronotus arborescens to expand in a little sea-water, and 
then deluged them with sulpho-picric acid, which by a rotatory move- 
ment of the hand is made to whirl round in the vessel. This treatment 
has the effect of fixing Nudibranehs before they can retract. Even with 
the more delicate species of Eolidee, which, with almost all other methods, 
break away the cerata from the body, this method is usually successful. 
The specimens are allowed to stand in this fluid, changed once or twice, 
for two or* three hours, according to size. They are then transferred to 
gradually increasing percentages of alcohol, rising up to about 75 per 
cent. ; they are afterwards stained in toto in picrocarmine, treated with 
acidulated alcohol, dehydrated, imbedded in paraffin in the usual way, 
and cut with the Cambridge “ Rocking ” microtome. 
Preparing Flukes for Investigation^ — Mr. W. G. Maccallum de- 
scribes a new method of preparing flukes for study. The worm should 
* Arch. f. Mikr. Anat., xlvi. (1895) pp. 290-305 (1 pi.). 
t Quart. Joura. Micr. Sci., xxxviii. (1895) pp. 276 and 7. 
X Proc. and Trans. Liverpool Biol. ISoc., ix. (1895) pp. 222-3. 
§ Veterinary Mag., ii. (1895) No. 7, 10 pp., 8 figs. 
K 2 
