28 Life and Iminortalty. 
albuminous compounds in exactly the same manner as docs 
the gastric juice of mammals, the digested matter being 
afterwards absorbed. In animals the digestion of albumin- 
ous compounds is effected by means of a ferment, pepsin, 
together with weak hydrochloric acid, though almost any 
acid will serve, yet neither pepsin nor an acid by itself has 
any such power. It has been observed that when the glands 
of the disc are excited by the contact of any object, espe- 
cially of one containing nitrogeneous matter, the outer 
tentacles and often the blade become inflected, the leaf thereby 
becoming converted into a temporary cup or stomach. 
The discal glands then secrete more copiously, the secre- 
tion becoming acid, and, moreover, some influence being 
transmitted by them to the glands of the exterior tentacles, 
causing them to emit a more abundant secretion, which also 
becomes acid. This secretion is to a certain extent antisep- 
tic, as it checks the appearance of mould and infusoria, and 
in this particular acts like the gastric juice of the higher 
animals, which is known to arrest putrefaction by destroying 
the microzymes. 
With animals, according to Schiff, mechanical irritation 
excites the glands of the stomach to secrete an acid, but not 
pepsin. There is strong reason to believe, too, that the glands 
of Drosera, which are continually secreting viscid fluid to 
replace the losses by evaporation, do not secrete the ferment 
proper for digestion when mechanically irritated, but only 
after absorbing certain matters ofa nitrogeneous nature. The 
glands of the stomachs of animals secrete pepsin only after 
they have absorbed certain soluble substances designatea 
peptogenes, showing a remarkable parallelism between the 
glands of Drosera and those of the stomach in the secretion 
of their appropriate acid and ferment. 
Not only animal matter, but also the albumen of living 
seeds, which are injured or killed by the secretion, are acted 
upon by the glands of Drosera. Matter is likewise absorbed 
from pollen, and from fresh leaves. The stomachs of 
