SALT AND WATER IN LIFE AND GROWTH 



143 



Fig. 54. Artificial Striated Structure (Liesegang Rings) 



(Natural size) 



"Liesegang Rings" are obtained by the simple slow mixing of two 

 solutions which interact with the formation of an insoluble substance. 

 We add gelatin to one of these solutions and pour it in a flat disk. After 

 it has set to a jelly, we place a drop of the second solution in the center of 

 this jelly. Without any further manipulation or interference a structure 

 is developed such as photographed here in natural size. In this instance 

 the jelly contains ammonium chromate, the solution placed upon this in the 

 center is a soluble silver salt. Numerous other substances of suitable 

 kind can be used to form such structures. 

 (Compare text on pages 145 and 146.) 



