146 DIFFERENTIAL STAIN FOE MUSCULAK AND FIBEOUS TISSUES. 



with different preparations. If the time allowed is too short, 

 the picric acid stain predominates. If, on the other hand, the 

 sections are left too long in the stain, the erythrosine is apt to 

 displace the picric acid. I have found that 15 to 30 seconds 

 usually gives the best results. 



4. The picro-erythrosine is then washed off with alcohol, and 

 the sections are dehydrated and cleared with xylol. 



In a specimen so stained the muscle fibres are yellow or 

 yellowish brown and the fibrous tissue is pink, the contrast often 

 being extremely sharp. Eed blood corpuscles are a brilliant 

 yellow, and the protoplasm of epithelial cells is yellow. 



This method is very useful for sections of uterine fibroids 

 and solid tumours of the ovary, and it shows up the striated 

 muscle fibres in a myo-sarcoma very distinctly. 



The stain somewhat resembles that of Van Gieson, but it has 

 the advantage that the erythrosine stain is more pleasing to the 

 eye than that of acid fuchsine, and, as far as my experience goes, 

 it is more permanent. 



Occasionally, after being kept for some time, the mixture 

 will be found to have lost its power of staining. This can be 

 remedied by the addition of one or tw^o drops of dilute acetic 

 acid, or it can be acidified more strongly and neutralised afresh 

 with calcium carbonate. 



If a soluble alkali be used instead of calcium carbonate, great 

 care must be taken not to add too much, since neither erythrosine 

 nor picric acid stain in alkaline solution. 



