Baer the animal and plastic parts, and did not touch the 

 subdivision of these layers into embryonic plates (418) . 



(106) Baer made a mistake, suggesting that Swammerdam 

 did not see the division of the ovum. In Bibia naturae, 

 Swammerdam gave a figure of the dividing ovum of frog (stage 

 of two blastomeres) . Reference to Swammerdam by Baer was not 

 accidental, Baer highly estimated the unusual accuracy of 

 Swammerdam 1 s observations, contained in his interesting 

 speech, made at the opening of the anatomical institute in 

 Kenigsberg in 1817). (Iohann Swammerdam' s Leben und 

 Verdienste urn die Wissenschaft (K. E. v. Baer. Reden. 



2-te Aufl., Braunschw., 1886. 5.3-34) (420). 



(107) Later on ("Autobiography", p. 383 and the following 

 pages) Baer decidedly raised an objection to the term "process 

 of fissure formation" (Furchungsprozess) , which at that time 



in particular was used by Kolliker and Reichert. The use of 

 this word, according to Baer's opinion, could be a source of 

 incorrect interpretation of the phenomenon. In spite of this 

 fair note, in German literature and later on, the division 

 was designated as "fissure formation", although, of course, 

 no one thought that the matter was the appearance of only a 

 fissure on the yolk surface. (421) 



(108) The discovery of the division process by Baer 

 was not completely unexpected by the embryologists. The 

 observations of Prevost and Dumas, as well as Rusconi, con- 

 stituted the preparation for this discovery. As already 

 stated, the French embryologists did not consider the appear- 

 ance of the fissure on the ovum surface as a sign of its 

 division into parts. Rusconi considered that the splitting 

 leads to this division, but the terminological disagreement 

 caused discussion between Baer and Rusconi which was based 



on misunderstanding. It is necessary to admit that Baer, in 

 his observations on splitting and in the analysis of this 

 phenomenon, has significantly gone beyond the Italian author. 

 Baer, much more correctly than many of his contemporaries, 

 looked for the process of splitting itself, comparing it to 

 the division of cells in the organism of the multicellular 

 animals. Thus, Shvani in his "Microscopical investigations" 

 wrote, that during the splitting of ovum "inside the yolk two 

 cells develop, in each of them two are formed again and so on", 



642 



