MINOR CARXIVORA. 



We have said that the margins of the leaves have 

 long been known to curve inwards in a peculiar 

 manner. A number of experiments were therefore 

 instituted in order to determine the cause of this 

 curvature, the result being that the movement was 

 produced by irritation of a particular kind. Touching^ 

 pricking, or scratching, produced no effect, neither 

 did drops of water, but the continued pressure of such 

 inanimate objects as fragments of glass, or objects 

 furnishing soluble matter, and infusion of meat, 

 caused the leaves to curl. The shortest period at 

 which a decided curvature was observed was about 

 two hours and a quarter. After bending inwards, and 

 remaining so for a short period, the margins open 

 and expand again, say in about twenty-four hours, but 

 are not stimulated to close again for some time. The 

 curvature only takes place in one direction, that is, 

 longitudinally, at cither margin, but the apex docs 

 not become inflected. When flies or other small 

 objects are placed near the margin of a leaf they arc 

 enclosed, or partly so, by the curvature. The glands 

 thus brought into contact with such objects pour out 

 their secretion. But why is the period of curvature 

 so short } We must here permit Mr. Darwin to give 

 his principal explanation. 



"We have seen that when large bits of meat, &c., 

 were placed on a leaf, the margin was not able to 

 embrace them, but as it became incurved pushed 



