102 Dr. Meyen on the Digestive Apparatus of Infusoria, 



which are said to lie between the globular stomachs and to 

 connect them one with the other. 



These views of Dr. Ehrenberg on the digestive apparatus 

 of the Infusoria have already been doubted in various quar- 

 ters. I have never participated in them ; in the first place^ 

 because I could never perceive these intestinal canals which 

 are said to connect the various stomachs one with the other ; 

 and secondly^ because many years ago I had observed in In- 

 fusoria of various genera that the supposed stomachs circu- 

 lated with more or less rapidity in their interior, resembling 

 exactly the rotatory currents of the globules in the cellules of 

 the Chares, Subsequently I frequently saw in VorticellcB^vAi^Vi 

 they had nine to fifteen large balls of indigo in their body, that 

 these revolved constantly round a fixed central point, and thus 

 evidently showed that in this case an intestinal canal connect- 

 ing the stomachs and in connexion at one extremity with the 

 oral and at the other extremity with the anal aperture could 

 not exist. 



What then, however, are those equally sized vesicles and 

 globules which occur in the interior of animalcules and have 

 been regarded as their stomachs ? This question will be ge- 

 nerally asked of me, and I have also put this question to my- 

 self, until by continued observation of this subject I have 

 ascertained the origin of these globules and vesicles. The 

 true Infusoria are vesicular animals, whose cavity is filled with 

 a gelatinous, somewhat slimy substance ; the consistence of 

 the membrane forming the vesicle is in some of these creatures 

 distinctly visible, and in several genera I have been able to 

 observe in this membrane a spiral structure plainly recogni- 

 sable, so that the structure of these Infusoria, in the main, ap- 

 peared to me to resemble that of the cells of plants. In the 

 larger Infusoria there proceeds from the mouth a cylindrical 

 canal (alimentary canal) obliquely through the membrane 

 which forms the animal ; the lower end of this canal expands 

 when it has taken up nutriment in a greater or less degree, 

 generally, however, to the size of the globules which occur in 

 the interior of these Infusoria. The inner surface of this por- 

 tion of the alimentary canal is beset with cilia, by the motion 

 of which the absorbed substances, both the nutritive sub- 



