the organic world from the lower water plants to man, 

 showing, in fact, the form of reproduction for evolution. 



N, P, Wagner's discovery of the phenomenon of paedo- 

 genesis, which served as the starting point for Baer's 

 discussions and also M, S. Ganin's detailed investigations 

 in this topic, attracted Baer's intense attention. Because 

 these works were considered evidence of the successes of 

 Russian embryology, Baer always showed great care for its 

 development. He energetically popularized works by Russian 

 authors in his reports, published statements and letters. 

 He was glad of the recognition of the importance of these 

 works by influential investigators abroad and expressed the 

 conviction that "there is yet no single route to us via the 

 printing press and book trades" (p. 22). 



It is interesting historically, however, that Baer's 

 other great work, in which he posed the question, "Do the 

 larvae of simple ascidiae develop initially like types of 

 vertebrates?"^^ wa s very controversial. 



The cause of his writing this paper was sensational . 

 As Baer wrote, A. 0, Kovalevsky discovered that ascidians, 

 which in their adult condition are so strongly differentiated 

 from vertebrates, at the beginning develop similarly to 

 vertebrates, "If this conclusion," Baer stated, "could have 

 been substantiated, the sensation would have been completely 

 valid, since Darwin's bold hypothesis that the higher organisms 

 have evolved over the course of time from the lower, the lowest 

 form differing absolutely from the highest, received great 

 support" (p. 1) . 



29 

 Outlining the content of Kovalevsky' s work, Baer again 



returned to the idea that "rigorous comparison of ascidian 



28. Baer, "Entwickelt sich die Larve einfachen Ascidien in der 

 ersten Zeit nach dem Typus der Wirbelthierefc" MEM. ACAD, 

 IMP. SCIENCES ST. PETERSB, ,VII Ser (1873), 19, No. 8, 

 pp. 1-35. 



29. A Kovalevsky, "Entwicklungsgeschichte der einfachen 

 Ascidien," ibid . (1866), 10, No. 15, 16 pp. 



480 



