Ouap. 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. 
Hematin—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 hematin, 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 inffected in two 
days ; the fourth only moderdtely so. On the third day the 
. glands in contact with the hematin 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 found that 
whilst 1°31 of fibrin, only 0456 of the hematin 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 by 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. 
