Dr. Meyen on the Digestive Apparatus of Infusoria. 103 



stances and foreign ingredients,, are forced round with an ex- 

 ceedingly great velocity, until they are compressed together 

 into the form of a perfect sphere. During this formation of 

 the globules, the stomach (for this organ can only be consi- 

 dered as such) is in free connexion with the alimentary canal, 

 and by the outer ciliary apparatus new substances are conti- - 

 nually driven into this canal and into the stomach ; but whe- 

 ther the alimentary canal between the oral aperture and the 

 stomach is also clothed with cilia I have not been able to ascer- 

 tain with certainty. As soon as the globule of the absorbed 

 substances has attained the size of the stomach, it is expelled 

 at the other extremity, and forced into the cavity of the ani- 

 malcule, immediately on which a new globule is formed with- 

 in the stomach, if -solid substances are present in the sur- 

 rounding fluid ; this second globule is also thrown into the 

 cavity of the animalcule^ and now pushes the first globule 

 with the intervening slime further forwards, and thus the for- 

 mation of similar globules from the absorbed substances is 

 constantly going on. These are the globules from the num- 

 ber of which Dr. Ehrenberg inferred the great quantity of 

 stomachs of these animals. If the surrounding fluid does not 

 contain much solid matter, these globules are also less com- 

 pact, and they then have the same appearance as we find 

 them in Infusoria in common uncoloured infusions^ where 

 such a globule at times only exhibits a few small particles, 

 and consists for the greater part of a slimy substance, with 

 which these are mixed. At times two such globules are 

 pressed in the interior of the body so forcibly together that 

 they remain in this connexion. 



If it is desired to observe the formation of these globules 

 very distinctly, the observation should be commenced imme- 

 diately on the Infusoria coming in contact with the coloured 

 fluid. The reception of the coloured matter takes place very 

 rapidly, frequently even in half a minute, and then it may 

 easily be perceived how one coloured globule after the other 

 passes from the stomach perfectly formed, and how in the 

 ParamcecicE) Keronice, and Vorticellce they are propelled down- 

 wards at the border ot the cavity of the animal, and how then 

 the new globule pushes the preceding one with the inter- 

 vening slime forwards, so that the first soon ascends on the 



