42 GENERAL HISTORY OF 



by the obsei"vation of an occasional circulation within the animal 

 of the vesicles (similar to that of the contents of the cells of Chara, 

 &c.), in Vaginicola, Vorticella, and in Loxodes hirsaria. 



This account of the digestive appai'atus, by Siebold, agTees gene- 

 rally, "with that given by Professor Boeck, of Sweden, (Oken. Isis for 

 1848). Again Focke states (Reports Eay Society, 1845) " that in 

 Loxodes, Bursaria, Paramecium aurelia, and in Polygastrica, he saw 

 the cavities filled with pigment, intersecting each other in varied 

 series, and concluded from this, that the digestive apparatus is not 

 separated from the parenchyma, but that the parenchyma of these 

 animals, consisting of cells, encloses the fluid nouiishment, received 

 from without in narrow spaces, which may be compared with the 

 intercellular passages of plants. The same observer also states, that 

 on colouiing the fluid containing various proboscidated monads, some 

 individuals remained quite colourless, whilst others were saturated 

 ■s\dth the pigment." 



In none of the families included by Ehrenberg under the general 

 denomination of Infusoria, is less indication of a polygastric structure 

 to be met "with than in the Closterina and Bacillaria — the Desmidiece 

 and Biatomacece, of other authors. It is true that that reno"wned 

 micrographer speaks in various places of the detection of stomach 

 sacs in several genera of the Bacillaria, but the appearances so 

 interpreted, resemble those met "ndth in the vegetable cells of acknow- 

 ledged Algae and of other plants, and to which no one has ever 

 thought of assigning a digestive function. These globules, or so- 

 called sacs, are stated to perform an intercellular rotation in the 

 Desmidiece, resembling that of the contents of the cells of Chara, 

 Valisneria, 8cc. (See Section on Bacillaria). 



But if Ehrenberg has encountered many opponents to his poly- 

 gastric hypothesis, he has had a few come to his support, and among 

 the rest, M. Eckhard, once a pupil. The latter speaking of the 

 digestive function, observes, "in such forms as are not too minute, 

 we can distinctly see how the nutriment, artificially supplied, con- 

 stantly takes a definite course in the body ; in some instances, the 

 first portion of the alimentary tube can, when not in action, be 

 observed, as in Epidylis grandis ; it is then frequently seen to be 

 covered on the inner sm-face with cilia, which, in the Oi)ercularia, 



