486 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
observations were in many cases effected by the investigation of the 
living animal. 
Division of Ceratium.* — Herr R. Lauterborn preserved his speci- 
mens in Flemming’s mixture, picrosulphuric acid, 45 per cent, iodine- 
alcohol, &c. But the first was best. In it the specimens were left for 
10 minutes and then washed. Treatment with gradations of alcohol 
followed. For [staining, Delafield’s bmmatoxylin gave clearest results 
for the chromatin of the nucleus. Paraffin sections were also cut for 
the study of the centrosomes, Heidenhain’s method of staining being 
followed. 
Study of Sporozoa. — Mr. J. Jackson Clarke f confirms the statement 
of Wolters, that Flemming’s fluid does not give good results with 
Gregarines. He adopted a method which he found most satisfactory, 
not only for Gregarines but for Coccidium oviforme , and for animal tissues 
in general. Small portions of the tissue are placed for 24 hours in Foa’s 
reagent, which is a mixture of equal parts of a saturated solution of 
corrosive sublimate in normal saline solution, and a 5 per cent, solution 
of bichromate of potassium or Muller’s fluid. The material is then 
transferred for a day to running water and afterwards placed on succes- 
sive days in 30, 60, and 90 per cent, alcohol. After this they are placed 
in absolute, and after saturation with chloroform are imbedded in paraffin. 
Care must be taken that the bath does not reach a temperature higher 
than 50°. The sections were cut with a Minot’s microtome, and fixed 
on the slide with albumen and glycerin. They were stained with 
Ehrlich’s acid hsematoxylin diluted with distilled water, and when they 
had assumed a brownish-pink colour were transferred to a bath of tepid 
tap water and left for at least two hours. Then for two or three minutes 
they were stained with a solution of Griibler’s water-soluble eosin, 
dehydrated, cleared by xylol and mounted in the usual way. The last 
mentioned solution was obtained by dropping a few drops of a strong 
alcoholic solution into a watch-glass filled with distilled water. 
Mr. G. Eisen,J in his investigations of the life history of Sperma- 
tobium , found that the following method was superior to any other. 
The hosts were stained in toto in very weak Delafield’s hsematoxylin, 
or in Ehrlich’s ammonia hfematoxylin. After hardening and sectioning 
in paraffin the slide fixing consisted simply of distilled water or of 
formalin and gelatin (1/2 per cent.) in water. This fixing is used as 
follows : — (1) Cover the space of the entire glass on the slide with 
several drops of the fixing so that the sections will float ; warm gently 
over a plate until the paraffin becomes slightly transparent, but not so 
long that it begins to melt ; let the fixing harden in the air during at 
least four hours, or better during the night ; the paraffin should be 
dissolved in pUre turpentine or xylol ; when the latter is at last removed 
by alcohol the slides are stained by a saturated solution of orange G 
in 33 per cent, alcohol. Attention is called to the very great advantages 
of gum Thus in xylol as a mounting medium, for it gives images which 
are far superior to those found with Canada balsam or dammar. 
* Zeitschr. f. wiss. Zool., lix. (1895) pp. 167-90 (2 pis.). 
+ Quart. Journ. Micr. Sci., xxxvii. (1895) pp. 287-8. 
% Proc. Cal. Acad. Sci., v. (1895) pp. 4 and 5. 
