862 CONCLUDING REMARKS Onar. XV. 
Pinguicula or Nepenthes, for these plants are not at all 
closely related to the Droseracee. But the difficulty 
is not nearly so great as it at first appears. Firstly, the 
juices of many plants contain an acid, and, apparently, 
any acid serves for digestion. Secondly, as Dr. Hooker 
has remarked in relation to the present subject in his 
address at Belfast (1874), and as Sachs repeatedly 
insists,* the embryos of some plants secrete a fluid 
which dissolves albuminous substances out of the 
endosperm ; although the endosperm is not actually 
united with, only in contact with, the embryo. All 
plants, moreover, have the power of dissolving albu- 
minous or proteid substances, such as protoplasm, 
chlorophyll, gluten, aleurone, and of carrying them 
from one part to other parts of their tissues. This 
must be effected by a solvent, probably consisting of 
a ferment together with an acid.t Now, in the case of 
plants which are able to absorb already soluble matter 
from captured insects, though not capable of true 
digestion, the solvent just referred to, which must be 
occasionally present in the glands, would be apt to 
exude from the glands together with the viscid secre- 
tion, inasmuch as endosmose is accompanied by 
exosmose. If such exudation did ever occur, the 
solvent would act on the animal matter contained 
within the captured insects, and this would be an 
act of true digestion. As it cannot be doubted 
that this process would be of high service to plants 
* ‘Traité de Botanique, 3rd 
edit. 1874, p. 844. See also for 
following facts pp. 64, 76, 828, 
831, 
+ Since this sentence was write 
ten, I have reseived a paper by 
Gorup- Besanez (‘Berichte der 
Deutschen Chem. Gese'\schaft,’ 
Berlin, 1874, p. 1478), who, with 
the aid of Dr. H. Will, has ae- 
tually made the discovery that the 
seeds of the vetch contain a fer- 
ment, which, when extracted by 
glycerine, dissolves albuminovs 
substances, such as fibrin, and 
converts them into true peptones 
