SECTION TWO 



6. Wash in water. 



7. Mount in Aquamount or glycerine or glycerine jelly. 



Results: 



Alpha-amino acids and proteins: blue to violet. 



Notes: 



{a) According to Serra (1947), the reaction is given not only by 

 all amino acids (except proline and hydroxyproline), peptides and 

 proteins, but by amines, aldehydes, sugars with free aldehyde and 

 keto groups, and by ammonia and ammonium salts. 



{b) Readers are referred to Serra's (1946) paper for more 

 detailed information. 



References : 



Serra, J. A. (1946). 

 Pflugers, W. (1926). 

 Ruhemann (1910). 



ORANGE G - CRYSTAL VIOLET 



(After Bensley) 



For secretion antecedents of serous or zymogenic cells. 



Solutions required: 



A. Osmic acid 2% • • • • 4 "^1- 

 Potassium dichromate 5% . . 4 ml. 

 Glacial acetic acid . . . . i drop 

 Distilled water 2 ml. 



B. Neutral gentian 



Orange G 8% aqueous . . 25 ml. 



Crystal violet 4% aqueous . . 25 ml. 



Mix thoroughly by shaking until almost complete 

 precipitation takes place ; then allow the preparation 

 to stand for an hour, afterwards collecting the preci- 

 pitate on a filter. Wash the precipitate on the filter 

 with about 250 ml. distilled water; then dry and dis- 

 solve it in 25 ml. absolute alcohol. 



327 



