I. On the constitution and mode of formation of food vacuoles in Infusoria, as illustrated by the history of the processes of digestion in Carchesium polypinum

Abstract

Since the time that Ehrenberg first formulated his celebrated “polygastric” theory, there have been few writers on the Infusoria who have not confirmed his observations while combating the interpretation of them given by him. For it was shown long ago that the “Magenzellen” of Ehrenberg are spherical food masses, and these, circulating with varying rapidity in the “endoplasm,” are so striking optically in most Infusoria that the literature of this group abounds in descriptions of or references to them. There is, however, a lack of any details which would throw light on the precise mode of origin of these ingesta, and yet this point has interest, for, while relatively large food masses are swallowed by certain of the ciliate Infusoria, very many forms are adapted only for the inception of minute solid particles, which seem far removed from the relatively large masses so noticeable within the animals.