336 



CYTOCHEMICAL TESTS ON EMBRYOS 



tinge. Lison (1936) follows a different procedure to demonstrate the presence 

 of phenolic compounds and axoproteids. Serra's (1946) procedure follows: 



a. Treat tissues for 2 to 3 minutes with saturated aqueous solution of sodium 

 carbonate. 



b. Add a few drops of diazo reagent, stir well, and observe in pure glycerine. 



The diazo-reagent (prepare just before using, keep cool) 



Place 1. 5 cc. of sulphanilic acid in a 50 cc. flask in an ice bath. 



This is made by dissolving 0. 9 grns. pure sulphanilic acid in 9 cc. 



of concentrated HCl, and adding water to make 100 cc. 

 Add 1. 5 cc. of a 5% aqueous solution of NaNOj, shaking well. 

 Add 6 cc. of NaN02 after 5 minutes, constantly shaking mixture. 

 Add cooled distilled water to make 50 cc. total volume. 



Nuclei of 

 spermatozoa 





Tails of 

 spermabozoa 



Modification of the Sakaguchi test 

 for Guanidine derivatives. Triturus 

 vulgaris testis. 



Courtesy J. R. Baker, 1947: Quart. 

 Jour. Microsc. Science. 88:115. 



3. Tryptophane : Tryptophane comprises from 1 to 3% of the great majority of 

 proteins. Its formula follows: 



HC- 



HC- 



H 

 C 



I 



C 



H 



C — C — CH2— CH(NH2) — COOH 



CH 



N 

 H 



