214 BIOLOGY AND ITS MAKERS 



It has been impossible lo discover a portrait of Wolff, 

 alihough J have sought one in various ways for several years. 

 The sccrctarv of the Academy of Sciences at St. Petersburg 

 writes that no portrait of AVolff exists there, and that the 

 Acadeni\- will gratefuU}' receive information from any source 

 regarding the existence of a portrait of the great acade- 

 mician. 



His sincere and generous spirit is shown in his correspond- 

 ence with Haller, his great opponent. " And as to the matter 

 of contention between us, I think thus: For me, no more 

 than for you, glorious man, is truth of the very greatest con- 

 cern. Whether it chance that organic bodies emerge from 

 an invisible into a visible condition, or form themselves out 

 of the air, there is no reason why I should wish the one were 

 truer than the other, or wish the one and not the other. And 

 this is your view also, glorious man. We are investigating 

 for truth only; we seek that which is true. Why then should 

 I contend with you?" (Quoted from Wheeler.) 



The Period of Von Baer 



What Johannes A 1 tiller was for physiology, von Baer 

 was for embryology; all subsequent growth was influenced 

 by his investigations. 



The greatest classic in embryology is his Development oj 

 Animals (Eniwickelungsgeschichte der Tiere — Beohachtung 

 iiud Reflexion^, the first part of which was published in 1828, 

 and the work on the second part completed in 1834, although 

 it was not published till 1837. This second part was never 

 fmished according to the plan of Von Baer, but was issued by 

 his publisher, after vainly waiting for the fmished manu- 

 script. The final j^ortion, which Von Baer had withheld, in 

 order to perfect in some particulars, was published in 1888, 

 after his death, but in the form in which he left it in 1834. 



