COLORING MATTERS. I(X) 



contents of all the tissue systems, with the 

 exception of the spiral ducts. 



Dilute acids induce at first the separation of 

 small yellow drops, which exhibit the Brownian 

 movement. Hot potash produces a brownish- 

 yellow color. Glycerine and water dissolve it. 

 Dried sections are rapidly extracted by water. 

 In this yellow fluid hydrochloric acid forms yel- 

 low, often radiate aggregates of chloride of ber- 

 beridin. 



GLOCOCAPSIN 



Is a red or blue pigment occurring in the cell- 

 walls of Gloeocapsa and certain filamentous algae. 

 It changes to a red, or brownish-red, under the 

 action of hydrochloric acid, and to blue or violet 

 when acted upon by potash. 



SCYTONEMIN 



Is a yellow or brown coloring matter which occurs 

 in the cell-walls of many Phycochromaceae. It is 

 changed to a verdigris-green by hydrochloric acid, 

 the yellow color reappearing on the addition of 

 alkalies. 



