. The Protozoa. Protozoa. 284 THE PROTOZOA considerable quantity of water accompanies the food particles, what- ever they might be, into the protoplasm, and forms the fluid of the gastric vacuole, and later physiologists have found that this water be- comes acid by gradual secretion from the surrounding protoplasm. (Fabre-Dumergue, Meissner, Metschnikoff, '89; Le Dantec, '90).1 It thus appears, if these observations be complete, that in these cases at least the food particles never come in direct contact with the pro-. Fig. 146. — Digestion in Keticulariida. D [Verworn.] A, B, C, D, E, success
. The Protozoa. Protozoa. 284 THE PROTOZOA considerable quantity of water accompanies the food particles, what- ever they might be, into the protoplasm, and forms the fluid of the gastric vacuole, and later physiologists have found that this water be- comes acid by gradual secretion from the surrounding protoplasm. (Fabre-Dumergue, Meissner, Metschnikoff, '89; Le Dantec, '90).1 It thus appears, if these observations be complete, that in these cases at least the food particles never come in direct contact with the pro-. Fig. 146. — Digestion in Keticulariida. D [Verworn.] A, B, C, D, E, successive stages in the disintegration of a ciliate {Colpodri) (c), in a pseudo- podium oi Lieberkuknia. toplasm, but are always suspended in the liquid of the vacuole. There are, however, certain exceptions to this rule, and with these in mind, it is not yet possible to regard the subject as definitely established. Food-taking in certain marine Rhizopoda is apparently accomplished without the formation of a gastric vacuole, and the prey, possibly a small ciliate, disintegrates while in contact with the plasm, and the disintegrated parts move about in cyclosis with the endoplasmic granules {Lieberkuknia, Gromia fluviatilis, Fig. 146). In these cases the digestive fluids must be in any and all 1 Cf., however, Greenwood ('94).. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Calkins, Gary N. (Gary Nathan), b. 1869. New York, The Macmillan company; London, Mamcillan & co. , ltd.
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