00' DROSERA ROTUNDIPOLIA. [Chap. VI. 



the former would excite the leaves, and yet not decrease the 

 casein to a j>erceptible degree. Schiff asserts " and this is 

 an important fact for us that " la caseine purifiee des 

 chimistes est un corps presque completement inattaquablc 

 par le sue gastrique." So that here we have another point 

 of accordance between the secretion of Drosera and gastric 

 juice, as both act so differently on the fresh casein of milk, 

 and on that prepared by chemists." 



A few trials were made with cheese; cubes of i^ of an 

 inch (1.27 mm.) were placed on four leaves, and these after 

 one or two days became well inflected, their glands pouring 

 forth much acid secretion. After five days they began to re- 

 expand, but one died, and some of the glands on the other 

 leaves were injured. Judging by the eye, the softened and 

 subsided masses of cheese, left on the discs, were very little 

 or not at all reduced in bulk. We may, however, infer from 

 the time during which the tentacles remained inflected, 

 from the changed colour of some of the glands, and from 

 the injury done to others, that matter had been absorbed 

 from the cheese. 



Legumin. I did not procure this substance in a separate 

 state; but there can hardly be a doubt that it would bo 

 easily digested, judging from the powerful effect produced by 

 drops of a decoction of green peas, as described in the last 

 chapter. Thin slices of a dried pea, after being soaked in 

 water, were placed on two leaves ; these became somewhat in- 

 flected in the course of a single hour, and most strongly so in 

 21 hrs. They re-expanded after three or four days. The 

 slices were not liquefied, for the walls of the cells, composed 

 of cellulose, are not in the least acted on by the secretion. 



Pollen. A little fresh pollen from the common pea was 

 placed on the discs of five leaves, which soon became closely 

 inflected, and remained so for two or three days. 



The grains being then removed, and examined under the 

 microscope, were found discoloured, with the oil-globules re- 

 markably aggregated. Many had their contents much 

 shrunk, and some were almost empty. In only a few cases 

 were the pollen-tubes emitted. There could be no doubt 

 that the secretion had penetrated the outer coats of the 



' ' Tjornnn,' *c. fom. II. p. 153. doiiht rtne to the notion of the 

 " [I'rofewRor HnmlorHon tells alcohol 8e(l In mnkltiT " chnil- 

 me that tbla difference la no cally preiiared cuiielu." K. D.] 



