260 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
solved in this fluid, the tissue to be examined should be treated there- 
with. Hen’s egg albumen is by far the best solvent for methylen-blue, 
not only because it gives satisfactory pictures, but also because it is 
easily and rapidly prepared. The white of one or two fresh eggs is 
filtered, and to the filtrate is added 1/4-1/2 per cent, methylen-blue solu- 
tion in sodium or ammonium chloride, or the methylen-blue in powder 
may be mixed with the albumen directly. Should the examination be 
a protracted one, the author dilutes the fresh albumen with an equal 
volume of 0 * 5 per cent, sodium chloride or 025 per cent, ammonium 
chloride solution ; and when the pigment is dissolved therein it is 
filtered, after which it is ready for use. 
In all the fluids the solution of the methylen-blue is made by adding 
to them only just sufficient of the pigment as will make 1/10-1/4 per 
cent, clear solution ; or to the powder may be added solutions of sodium 
or ammonium chloride, and these afterwards mixed with serum or 
albumen. 
In certain special cases satisfactory pictures may be obtained by 
spreading the tissue to be examined on a slide, keeping it moist with 
serum or albumen, afterwards adding a few grains of the methylen- 
blue powder. This procedure is more rapid than the ordinary method, 
and even this may be hastened by adding a little of the dry pigment 
during examination. When properly carried out, only the nerves, their 
endings, and the cells are stained, and the time required is from three- 
quarters to one hour, though occasionally double this time is necessary. 
Criticism of Golgi’s Method.* — Dr. B. Friedlaender points out that 
in Golgi’s method several delusive appearances are inherent, and shows 
from special preparations of egg-albumen, celloidin, the earthworm, and 
also from old preparations, that precipitates occur which are barely 
distinguishable from those indicative of nervous tissue. The intention 
of the author is not so much to contest the general validity of the con- 
clusions arrived at by Golgi’s method as to point out sources of error 
intrinsic to the method. 
Very Dilute Hsematoxylin Solutions.! — Prof. 0. Israel notes the 
advantages of slow staining with very dilute solutions, to which Rawitz 
recently called attention. This, he says, is a familiar method, and much 
used. Alum-solutions of the various hasmatoxylins are all useful, and 
very dilute solutions of carmine and some anilins (e. g. R. Pfeiffer’s 
carbol-fuchsin) give beautiful results. 
(5) Mounting-, including- Slides, Preservative Fluids, &c. 
Preserving Rotatoria. — Mr. C. F. Rousselet has a second paper on 
the methods of preserving Rotatoria, in which, as many of our Fellows 
know, he has been peculiarly successful. His principle, that of nar- 
cotising, killing, fixing, and preserving in a watery-fluid not appreciably 
denser than water, remains the same, but a number of improvements have 
been made in the details of the process. Of the reagents before advised 
it is now recommended that osmic acid be omitted from the preservative 
* Zeitschr. f. wiss. Mikr., xii. (1895) pp. 168-76 (1 pi.). 
t Anat. Anzeig., xi. (1895) pp. 454-6. 
X Journ. Quekett Micr. Club, 1895, pp. 5-13. 
