in which he wrote: The process of division of the amphibian 

 ova is nothing more than successively accomplished generic 

 action (GEBURTSACT) of the maternal cells, repeatedly 

 invested in each other. 



T. Bischoff, working on the embryology of mammals and 

 publishing in the period from 1842 to 1852 a monograph 

 about the development of man, rabbit, dog and guinea pig, 

 also did not reach a clear understanding of processes of 

 division and did not recognize the spheres resulting from 

 division as cells; since in his opinion, the cell must 

 possess a cavity, but the spheres resulting from division 

 are filled with yolk, the nuclei of the blastoderms were 

 taken by Bischoff as fat droplets. 



A. K8 Hiker** went much further in the analysis of the 

 process of ovum division, admitting the direct continuity 

 of the blastoderms and those cells from which the embryo is 

 built in later stages. 



In all these cases the discussion was about the forms of 

 development, complicated by the great quantity of yolk in 

 the centrolecithal and telolecithal ova. The nature of the 

 occurrence there of superficial and discoidal division was 

 explained much later, after the introduction of sectioning 

 in embryology. 



A more distinct presentation on the phenomena of 

 division was stated by Baer in his work on the development 

 of amphibia, 7 but especially in the work noticed by his 

 contemporaries and later forgotten on the development of the 

 ova of the sea urchin. 8 



Certain embryologists of the thirties and the forties 

 nearly approached the correct interpretation of the phenomena 

 of the ovum division. They include KClliker, then Loven,9 



6. A. KSlliker, ENTWICKELUNGSGESCHICHTE DER CEPHALO- 

 PODEN (Zurich, 1844), 180 pp. 



7. See Chapter 21 . 



8. See Chapter 23. 



9. S. L. Loven, "Bidrag til kannedomen af Molluskenas 

 untveckling," K. VET. AKAD . HANDLINGAR (1839), 

 pp. 227 - 241. 



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