CUAP. VI. DIGESTION. 121 



globulin were not corroded or rounded by the secretion of 

 Drosera, though some soluble matter was certainly extracted 

 from them and absorbed by the glands. 



Hanmatin. Some dark red granules, prepared from bullock's 

 blood, were given me ; these were found by Dr. Sanderson to 

 be insoluble in water, acids, and alcohol, so that they were pro- 

 bably hsematin, together with other bodies derived from the 

 blood. Particles with little drops of water were placed on 

 four leaves, three of which were pretty closely inflected in two 

 days ; the fourth only moderately so. On the third day the 

 glands in contact with the hsematin were blackened, and 'some 

 of the tentacles seemed injured. After five days two leaves 

 died, and the third was dying ; the fourth was beginning to re- 

 expand, but many of its glands were blackened and injured. 

 It is therefore clear that matter had been absorbed which was 

 either actually poisonous or of too stimulating a nature. The 

 particles were much more softened than those kept for the same 

 time in water, but, judging by the eye, very little reduced in 

 bulk. Dr. Sanderson tried this substance with artificial digestive 

 fluid, in the manner described under globulin, and foiind that 

 whilst T31 of fibrin, only 0'456 of the hsematin was dissolved 

 in an hour ; but the dissolution by the secretion of even a less 

 amount would account for its action on Drosera. The residue 

 left by the artificial digestive fluid at first yielded nothing more 

 to it during several succeeding days. 



Substances which are not Digested l>y the Secretion. 



All the substances hitherto mentioned cause pro- 

 longed inflection of the tentacles, and are either com- 

 pletely or at least partially dissolved by the secretion. 

 But there are many other substances, some of them 

 containing nitrogen, which are not in the least acted 

 on by the secretion, and do not induce inflection for a 

 longer time than do inorganic and insoluble objects. 

 These unexciting and indigestible substances are, as 

 far as I have observed, epidermic productions (such 

 as bits of human nails, balls of hair, the quills of 

 feathers), fibro-elastic tissue, mucin, pepsin, urea, 

 chitine, chlorophyll, cellulose, gun-cotton, fat, oil, and 

 starch. 



