CHAPTER 19 



THEORETICAL INTRODUCTION 

 TO THE SECOND VOLUME OF UBER ENTWICKLUNGSGESCHICHTE 



The second volume of Baer's basic work includes the 

 third part, "Lectures on the origin and development of 

 organic bodies, read to physicians and prospective students 

 of nature in the form of an introduction to a deeper 

 study of the history of development," and the fourth part, 

 "Studies of the history of human development ,"^ The third 

 part begins with a theoretical introduction, which presents 

 the basic principles of the history of development. Baer 

 then moved to a systematic statement of the embryological 

 data for all classes of vertebrates. 



A superficial acquaintance with the third part can give 

 the impression that he repeated the first part. Such a 

 conclusion is not fair, because the first part stresses the 

 chronology of development and the individual steps characterized by 

 the condition of the different organs. The third part represents a 

 related description of development of the organs and their systems. 



For the characteristics of Baer's general opinions, the 

 fairly extensive theoretical introduction, entitled 

 "Statement of the Task," holds great interest (§ 1). Baer 

 began with the cardinal question about what organic life is, 

 remarking that scientific information about life is incomplete 

 because of the impossibility of accurately indicating the 

 beginning of this process. When the question, "What, in 

 essence, is the life of the organic body," is asked, a typical 



The fourth part is not included in the second volume of 

 the Russian version? in it are listed only the human 

 embryos investigated by Baer. (Ed.: Nor is the fourth 

 part in the original German edition. It was printed 

 later, as explained in Chapter 21.) 



365 



