124 Dr. C. F. J. Lachmann on the Organization of Infusoria, 



ance* in its original meaning, and we may refer to it in common 

 with the modification which it has undergone in Germany, as 

 in both we have to combat the opinion that the mass rotating 

 in the interior of the body of the Infusoria is to be regarded as 

 a part of the parenchyma of the body, whilst we may rather 

 consider it, with Ehrenberg, as chyme, or the contents of a di- 

 gestive cavity. 



The principal modification which was effected in Dujardin^s 

 opinion, in Germany, is, as is well known, the further develop- 

 ment of the analogy of an Infusorium with an animal or vege- 

 table cell pointed out by Meyen in 1839, and which has been 

 especially adopted by Von Sieboldf and Kolliker J. According 

 to them, the whole body of an Infusorium consists of a cell- 

 membrane and its tenacious fluid contents, both of which are 

 contractile (the contractile space, or the " seminal vesicle '' of 

 Ehrenberg, was then only a contractile part of the cell-contents) : 

 the cell-nucleus was seen in the body regarded by Ehrenberg as 

 the testicle, and the nucleolus of the cell was found in a corpuscle 

 not unfrequently placed in the nucleus, but in many cases 

 (curiously enough for the cell-theory) lying close to it. No 

 hesitation was caused by the fact that the cell had an orifice, 

 the mouth, from which a tube hung down as an oesophagus 

 into its interior. The existence of an anal opening was generally 

 denied, and it was supposed that the unserviceable matters were 

 pushed out through any part of the cell-wall ; at the utmost it 

 was admitted that a particular portion of the cell-wall was to be 

 regarded as the anal region, which was peculiarly adapted for 

 this purpose. 



If we may, a priori^ regard the existence of unicellular animals 



* Perty supports it in his book ' Zur Kenntniss kleinster Lebensformen ' 

 by the most superficial and inexact figures. During the past year Perty 

 has pubHshed a letter, in which he attacks Ehrenberg in the most savage — 

 one may even say unjustifiable manner, and entirely forgets the great 

 services done by this naturalist to our knowledge of the Infusoria. With- 

 out noticing whether and how far his reproaches are just, the spirit in which 

 they are made is certainly not to be tolerated, and Perty, of all men, has 

 the least cause for making such statements, as by the slight alteration of a 

 few names, a great part of his charges might be turned against himself with 

 equal, if not greater propriety. I shall be excused if, as a proof of this, 

 I here reprint one of Perty's strongest expressions with such alterations ; the 

 variations from Perty's original are shown by the insertion of his expressions 

 in parentheses : — " Establishment of that ridiculous monster : Phytozoidia 

 (Polygastrica), in which the most incompatible things: Infusoria of a 

 truly animal nature, creatures of doubtful position, and decided plants of 

 various groups (Rhizopoda, Infusoria, Phytozoidia, decided plants of 

 various groups) are thrown together into a monstrous whole." 



f Zeitschrift fiir wiss. Zoologie, i. p. 270. 



X Ibid. i. p. 200. The theory of the animal cell in Schleiden and Nageli's 

 Zeitschrift fiir wissenschaftliche Botanik, 1845, &c. 



