A RESUME OF THE USES OF FORMALIN. Tl 



effect on connective tissues, smooth and striated muscle, and 

 embryos. Many other observers condemn its use without being 

 so specific as Lachi. 



The exceptions, where it gives satisfactory results, are mucous 

 membranes and the central nervous system. I have used it in 

 five per cent, solution for hardening cystic adenoma of the ovary 

 with good results ; also for the mucous membrane of the uterus. 

 Lachi, who has condemned its use for all other tissues, speaks 

 well of its action on the central nervous system. Van Gieson has 

 employed it in four, six, and ten per cent, solutions for hardening 

 the central nervous system. The ganglion and nerve fibres were 

 well fixed. Sections stain well wuth Weigert's haematoxylin method. 

 He has also used it for hardening the central nervous system for after- 

 staining with Rehm's modification of Nissl's method. The results 

 were good, but not quite so sharp as with alcoholic hardening. 



The best results for microscopic work are obtained when for- 

 malin is combined with other fixing reagents. When it is used 

 in .combination with the chrome salts, more rapid penetration is 

 obtained, whereby the time required for hardening is shortened. 

 I have used a solution of formaUn in Miiller's fluid made as 

 follows : 



Potassium dichromate ... ••• 2 grms. 



Sodium sulphate ... ... ••• 2*5 „ 



Two per cent, solution of formalin ... 100 c.c. 



With this'fluid I have obtained excellent preservation of the ovary, 

 the uterus, etc. At the end of forty-eight hours the specimen is 

 cut into slices an eighth of an inch thick ; these are washed in 

 water for two hours ; they are then placed in alcohol for twelve 

 hours, and then carried through the usual processes of embedding 

 in celloidin. Specimens hardened in this manner show no shrink- 

 age, and the tissue elements are well preserved. 



Landowsky recommends the following fixing fluids for mitotic 

 figures in cells : 



I. Water ... ... •.• 20 c.c. 



Alcohol (ninety-five percent.) ... 10 „ 

 Formalin ... ••• ••• 3 »' 



Hydric acetate ... ... ••• o"5 » 



