626 PHARMACEUTICAL BOTANY 
of each half of the blade are three spine-like, sensitive hairs 
disposed as angles of a triangle. Each of these sensitive hairs 
is composed of elongated cells whose protoplasmic contents show 
Fic. 474.—Dionza muscipula, The Venus Fly Trap. (From Jenkins’ “Interesting 
Neighbors,’’) 
movement. At the base of each is a cylindrical mass of small 
cells which permits the stiff hair to be bent over. These sensitive 
hairs are highly irritable and capable of receiving and transmit- 
ting a stimulus. Further, over the entire upper surface of 
