Tue MIcRoscopE. 85 
DISSOCIATING FLUIDS. 
Dissociating fluids are those which dissolve or soften cer- 
tain parts of a tissue without affecting the other parts, so that 
by shaking or teasing, the unaffected portions can be isolated. 
IODIZED—SERUM. 
A few crystals of iodine are added to blood-serum or amni- 
otic fluid until it is of a ight brown color. It will dissolve the 
cement substance between cells in from one to two days. It is 
generally useful as a dissociating fluid. 
CHROMIC ACID. 
Very weak solutions are used, not stronger than .02 per 
cent. In two or three days it acts sufficiently to allow the sep- 
aration of the fibrilla of muscle and the nerve cells of the 
spinal cord. 
OSMIC ACID. 
From a.l to a 1 per cent. solution is useful for general 
purposes. 
MULLER’S FLUID. 
This fluid is useful for the stomach and kidney. 
SULPHURIC ACID. 
This acid is useful for isolating the cells of cornified epithe- 
lium, nails, etc. The cells: are placed in the acid for a short 
time when they are removed and thoroughly washed in water 
to which has been added a few drops of ammonia. 
HYDROCHLORIC ACID. 
A fifty per cent. solution is useful for isolating the urinif- 
erous tubules of the kidney. The section of fresh kidney 
should be thin, and it should remain in the acid from ten to 
fourteen hours, when it is washed in alkaline water. 
CAUSTIC POTASH. 
A thirty per cent. solution is useful for the muscular and 
nervous tissues. 
NORMAL FLUIDS. 
In preparing specimens for examination, and while 
they are being examined, it is often desirable to have them 
