Chap. I. FOOD AND DIGESTION. 43 



within the cells. My son examined some 

 leaves of the ash and many of the lime, 

 which had fallen off the trees and had been 

 partly dragged into worm-burrows. It is 

 known that with fallen leaves the starch- 

 grains are preserved in the guard-cells of the 

 stomata. Now in several cases the starch had 

 partially or wholly disappeared from these 

 cells, in the parts which had been moistened 

 by the secretion ; while it was still well pre- 

 served in the other parts of the same leaves. 

 Sometimes the starch was dissolved out of 

 only one of the two guard-cells. The 

 nucleus in one case had disappeared, together 

 with the starch-granules. The mere bury- 

 ing of lime-leaves in damp earth for nine 

 days did not cause the destruction of the 

 starch-granules. On the other hand, the im- 

 mersion of fresh lime and cherry leaves for 

 eighteen hours in artificial pancreatic fluid, 

 led to the dissolution of the starch-granules 

 in the guard-cells as well as in the other 

 cells. 



From the secretion with which the leaves 

 are moistened being alkaline, and from its 

 acting both on the starch-granules and on 



