404 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Prof. Biitsclili adds : — “ You must not doubt the correctness of the 
phenomena which I have described if the first trials do not give the 
desired results.” 
The student may also be referred to the account given by M. Yves 
Delage * of his experiences in Prof. Biitschli’s laboratory at Heidelberg. 
Method of Examining Network of Muscle-fibres. f — Mr. C. F. 
Marshall adopted a modification of Mays’ method of demonstrating nerve- 
endings in muscle. Mays used a mixture of 20 parts arsenic acid (1/2 per 
cent.), 4 parts gold chloride (4 per cent.), and 1 part osmic acid (2 per 
cent.), but this, while preserving the nerve-endings, disintegrates the 
muscle-fibre by the action of the arsenic acid. Mr. Marshall, after 
several experiments, used 20 parts acetic acid (1 per cent.), 4 parts gold 
chloride (1 per cent), and 1 part osmic acid (1 per cent.). The muscle- 
fibre was placed in this solution for fifteen minutes after previous im- 
mersion in acetic acid (1 per cent.) for a few seconds ; then in acetic acid 
(1 per cent.) again in a warm chamber for one or two hours. 
Mounting Spermatozoa of Salmonidae. — Mr. F. M. Walford, at the 
meeting on April 16th, said: — “Having occasion lately to examine the 
spermatozoa of the English brook trout (Salmo fario) and the American 
trout (/S\ fontinalis), I found it would be advantageous to have permanent 
mounts at my disposal. Mr. E. M. Nelson has suggested that the com- 
munication to the Boyal Microscopical Society of a brief note descriptive 
of the method adopted might be of assistance to students of this branch 
of science. 
The collection of the milt containing the spermatozoa flowing from 
a spawning fish presents no difficulties when a medium is used which 
will preserve the spermatozoa without coagulating them. Alcohol or 
acetic acid, even when dilute, coagulate the milt, and should be avoided. 
One part glycerin to five of water is a fairly good medium, but the 
aqueous solutions of phenol or corrosive sublimate of about 2J per cent, 
are preferable. 
The majority of text-books recommend glycerin and water for 
mounting spermatozoa, and hence this was one of the first media tried, 
but the resolution, even with 1/12 oil-immersion, was most unsatisfac- 
tory. The result of a number of experiments in staining may be summed 
up in the statement that the effect of staining is to make the heads more 
prominent and the filaments less visible. Specimens collected in 2J per 
cent, and mounted in IJ per cent, solution of corrosive sublimate looked 
fairly well for a time, but after a few months the heads of the sper- 
matozoa gradually dilated and showed signs of disintegration. 
A suggestion was made that, as probably a medium of low refractive 
index was desirable, it might be practicable to mount the spermatozoa dry 
on the cover-glass. So far I have not succeeded in doing so, but future 
experiments in this direction may be productive of better results. I was 
told by a friend that at one of the hospitals Farrant’s medium was used 
for human spermatozoa, and the idea occurred to me that, as working in 
Farrant often produced where not desired a plentiful crop of air-bubbles, 
it might be possible to take advantage of this peculiarity and show the 
* Arch. Zool. Exper. et Gen., v. (1880) pp. xliii.-xlviii. 
t Quart. Jourru Micr. Sci., xxxi. (1890) pp. 73-4. 
