distribute the division from the dark pole towards the light 

 pole is retained; therefore in the region of the latter the 

 blastomeres are always larger and distributed less regularly. 

 "All this indicates," Baer concluded, "that the determination 

 of division must originate from the rudimentary orificel3 and 

 its canal. The exact geometrical characteristics of the first 

 divisions depend on the rudimentary orifices and forms the 

 initial point of division. The canal marks the axis. This 

 confirmation, apparently, is based on those cases where the 

 rudimentary orifice is sufficiently distant from the center 

 of the region. All fissures of division preserve the usual 

 position to the rudimentary orifice and its canal, and 

 therefore the equatorial fissure on one side advances deeply 

 towards the light region (p. 501) . 



Interpreting the "determinations of division originating 

 from the rudimentary orifice and its canal," Baer considered 

 it unquestionable that "divisions are performed under direct 

 influence of a producing substance" (he means the substance 

 of sperms) . It is true that Baer erroneously indicated that 

 in fertilization "not the seminal animals, but the fluid or 

 even the more delicate parts of sperms play the role" (p. 503), 

 because he could not discover the penetration of spermatozoa 

 in the ovum. 



Baer's extremely interesting analyses of development 

 begin from the division of the ovum into its separate parts. 

 An initial individual ovum is divided into countless numbers 

 of individualities, each of them with negligible importance 

 which proves to be only an elementary component of the new 

 individual. "A vital process (the process of development) 

 which dissolves the initial individuality is not quite 

 destroyed, because fron; its fragments the new individual 

 originates. In the latter, when the process of division has 

 gone sufficiently far, the rudiment separates from the yolk, 

 and in the rudiment the embryo of the future frog is set 

 apart" (p. 504) . 



13. For example, from place of entry of the spermatozoan 

 and its way into ooplasm. 



424 



