52 



THE POPULAR SCIENCE MONTHLY, 



ing many hours, and even days. It should be mentioned that, when 

 excited by soluble matter of the proper kind, not only the tentacles, 

 but the disks, are inflected and close in about the object. There is 

 thus formed out of the leaf a stomach ; a comparison that Mr. Dar- 

 win has proved to be no fanciful one. Space will not permit giving 

 even examples of his exhaustive experiments ; to the book itself must 

 be referred those who may doubt their thoroughness, or question the 

 conclusions drawn from them. 



Fig. 3. Dro?ft3 i rotundifolia. Leaf (en- 

 larged) wuu uu the teutacles closely in- 

 flected. 



Fig. 4. Drosera rotusdipolia. Leaf (en- 

 larged) with the tentacles on one side in- 

 flected over a bit of meat. 



It is proved that the leaves are capable of true digestion, and that 

 the glands absorb the digested matter. The correspondence between 

 the secretion of the Drosera and the gastric juice of animals is shown 

 in that which it fails to digest as well as that which it succeeds in 

 digesting. As is well known, the gastric juice contains an acid and 

 a ferment, both of which are requisite for digestion ; so it is with 

 the secretion of Drosera. When the stomach of an animal is mechan- 

 ically irritated, it secretes an acid ; when bits of glass are put on the 

 glands of Drosera^ the secretion and that of the surrounding glands 

 are increased in quantity and become acid. The stomach of an animal, 

 however, does not secrete its proper ferment, pepsin, until certain 

 substances called peptogenes are absorbed ; matter must be absorbed 

 by the glands of Drosera before they secrete their proper ferment. 

 Like gastric juice, the secretion of Drosera has antiseptic properties. 

 Meat is dissolved by each in the same manner and by the same stages. 

 It promptly dissolves cartilage, a substance so little aflTected by water. 

 It dissolves bone, and even the enamel of teeth. In short, there is no 

 doubt that the ferment in both cases is closely similar if not identi- 

 cally the same, a fact in physiology which may well be called won- 

 derful ! 



