272 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
of the preparations thus treated wore placed for one to two days in acetic 
acid, when subsequent staining was usually unnecessary ; others were 
stained, either in mass or on slides, by means of Flemming’s saffranin- 
gentian-orange method. 
The advantage of the picric and platinum method is that there are 
revealed not only the most subtle details of the nucleus, but also the 
finest structural relations, and that with great clearness and regularity ; 
while there is no crumpling or swelling of the cell or nucleus. Careful 
measurement has convinced the author that the size and general habit of 
the cells and nuclei are remarkably similar to those of the living tissue. 
Preparation of Eggs of Trout.* — Prof. H. Blanc had some difficulty 
in studying the eggs of Trulta lacustris , as they are too large to be 
observed directly under the Microscope, and are somewhat opaque. As 
they have a thick shell-membrane, and as the yolk hardens more than the 
blastoderm, it was necessary to discover some speciall method. At last, 
eggs fertilized by the Russian method were fixed in a mixture of 600 vols. 
water, 2 vols. concentrated sulphuric, 100 vols. concentrated picric, and 
8 vols. glacial acetic, acids. After remaining for several hours, or even 
days, in this mixture, the eggs were opened in 10 per cent, acetic acid ; 
this partly dissolved the nutrient yolk and allowed the germs to be picked 
out. The latter were then treated with 80 per cent, alcohol till they 
were completely colourless, then preserved in absolute, and afterwards 
stained with borax-carmine, before being placed in toto in glycerin or 
balsam. This method is recommended as giving good results even in 
the hands of beginners. 
Preparing Molluscan Ova.j - — Mr. E. J. Conklin finds the following 
to be the best method of preparing surface- views of the whole egg or 
embryo : — Transfer the object, previously fixed in Kleinenberg’s stronger 
picro-sulphuric, 70 per cent, and 95 per cent, alcohol, gradually from 
alcohol to water ; stain from five to ten minutes in a solution of Dela- 
field’s (Grenacher’s) hmmatoxylin diluted about six times with distilled 
water, and rendered slightly acid by a trace of hydrochloric acid ; 
dehydrate and clear in oil of cedar or cloves ; mount in balsam, sup- 
porting the cover-glass, so as to prevent crushing. By occasionally 
softening the balsam with a drop or two of xylol, and slightly moving 
the cover-glass, the objects can be rolled into any position desired. This 
method has also been successfully employed in the preparation of surface- 
views of the embryo chick, English sparrow, and the eggs and embryos 
of Annelids and Echinoderms. One great advantage of it is that the 
preparations are permanent. 
Study of Spermatogenesis of Crustacea. J — M. A. Sabatier made 
use of very numerous and various reagents, always dealt with organs 
taken from living specimens, and used most of the known fixing reagents. 
In rapid teasings he found admirable Ripart and Petit’s cupric fluid, 
whether used pure or with the addition of 1 per cent, osmic acid solution. 
With this and acetic-methyl-green he was able to very profitably study 
nuclein, whether in or out of the nucleus. 
* Ber. Naturf. Gesell. Freiburg i/B., viii. (1894) p. 163. 
t Amer. Natural., xxvii. (1893) pp. 1026 and 7. 
t Acad, de Montpellier, Mem. Sec. Sci,, i. (1893) pp. 21 and 2. 
