did offer an especially congenial environment for an 

 embryologist who was an epigenesist, and perhaps the reasons 

 should be better examined. 



CHAPTER 4 provides a useful outline of Wolff's dis- 

 sertation - both the original Latin of 1759 and the German, 

 more "popular" version of 1764. The Latin criticized earlier 

 epigenetic suggestions and reflected a great deal of respect 

 for Haller, but Blyakher claims that Wolff appealed to 

 Haller only because he sought the latter 's support and that 

 Wolff consistently rejected any tendency toward Haller's 

 preformationist views. In the German, Wolff provided an 

 epigenetic discussion of development and expressed opposition 

 to rigorously mechanical understandings of vital phenomena. 

 Blyakher' s description of Wolff's work is valuable, but the 

 reader should be aware that Blyakher has probably had to 

 strain the data here more than elsewhere to support his 

 thesis about Russian priorities in embryology and his view 

 that Wolff was one of the Russian "good guys" on the progres- 

 sive path to modern scientific embryology. Again, the reader 

 should recall that this was published in 1955, just shortly 

 after other Russian publications of histories of embryology 

 and translated embryological works. 



CHAPTER 5 remains somewhat more descriptive, providing 

 a valuable discussion of Wolff's relatively rarely read ON 

 THE FORMATION OF THE INTESTINE. Here begins Wolff's 

 articulated disagreements with Haller over whether develop- 

 ment occurs gradually and epigenetically or by unfolding of 

 preformed material. "I consider it proven that the intestine 

 is doubtlessly thus formed (by rolling of material) and 

 did not exist previously in an invisible form, ready to 

 appear at the appropriate moment, "wrote Wolff in opposition 

 to Haller. Just because he could not see the parts early on 

 does not mean that they could not exist already, Wolff 

 realized, but he believed that in fact the parts are only 

 formed as the result of a gradual process. Unfortunately, 

 Wolff's work was little known, even after a translation into 

 German appeared. Only much later was Wolff appreciated, accord- 

 ing to Blyakher, and it took figures such as von Baer, the 

 American biologist William Morton Wheeler, and the embryo- 

 logist-historian of science Joseph Needham to evaluate properly 

 Wolff's "fatal blow for preformation." 



