28 o 
Mechanical Reception of Nutriment into the [May, 
VII. ON THE MECHANICAL RECEPTION OF 
NUTRIMENT INTO THE 
INTESTINAL MUCOUS MEMBRANE. 
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* T has long been known that the assimilation of nu- 
triment in those groups of Protozoa which are 
destitute of a mouth, or an oral opening, is thus 
effe&ed : the body, consisting of “ sarcode ” (protoplasm) 
emits pseudopodia, which seize upon the particles of food, 
surround, and imbibe them. In each of the pseudopodia 
there can be observed a double current of the protoplasm — 
a centrifugal and a centripetal. 
Until recently this mode of taking up nourishment was 
supposed to be confined to the Protozoa, whilst certain and 
trustworthy observations were wanting as regards the 
Metazoa. Latterly, however, some exceedingly interesting 
results have been obtained concerning the Ccelenterata. 
Both in the Sponges and in the true Ccelenterata nourish- 
ment is taken up essentially in the same manner as in the 
Protozoa, — the only difference being that here, in accord- 
ance with the division of labour characteristic of the body 
of a Metozoon, this process is carried on within the region 
of the endoderm. 
The cells lining the nutrient cavity possess, like the entire 
body of the Protozoa, an aCtive amoeboid mobility, — i.e., 
they retain, to a certain extent, their individuality as inde- 
pendent elementary organisms, and they flow round and 
envelope the particles of nourishment by means of their 
pseudopodia, exactly in the same manner as do the 
Protozoa. This power belongs either to the cells of the 
entire endoderm, or it is, in other cases, limited to certain 
regions. 
The question now arises whether this method of inter- 
cellular digestion extends also to types higher than the 
Ccelenterata. This, according to the researches of a series 
of investigators, is actually the case. Thus, in the first 
place, the amoeboid movements of the intestinal epithelium 
were direCtly observed in the Turhellaria, animals of a very 
low rank. 
Subsequently it was found that numerous Turbellaria, 
whether possessing an intestinal canal or not, take up their 
nourishment direct into the parenchyma. But not all 
