side of the new-formed intestinal canal. "It must be noticed," 

 IVolff wrote later, "that the intestinal canal, even when it is 

 completely formed is so similar to the intestine that it may be 

 mistaken for it; it also significantly differs from the 

 intestinal canal in the mature condition" ($ 62, p. 450). 



In his first works, even in the polemical part of the 

 German "Theory of Generation," Wolff had not touched on the 

 disagreement with Haller. Only here, in the work about the 

 development of intestine, he for the first time noticed a diver- 

 gence from Haller concerning the periods of appearance of the 

 formed parts of the intestinal canal, which the "famous 

 Haller" saw first in the fifth to seventh day. Later, however, 

 Haller informed IVolff about earlier periods — about the fourth 

 day. Wolff also observed the formed digestive canal within 

 three and a half days after the beginning of incubation. The 

 deep divergence lies, however, not in what Haller said but 

 in the moment when the organs of digestion become visible. 

 Haller gave no information about their development, while 

 Wolff showed the gradual formation of the intestinal canal. 



"The first rudiment of intestine and stomach," Wolff 

 wrote, "can be recognized .... by successive changes and by 

 the processes of development, which appear much earlier" 

 (p. 460). "The part of the membrane forming the commissure is 

 the internal or villous skin of the intestine. Thus, the 

 intestine regarded as a whole is the opened intestine. In 

 order for it to become a whole canal, its lateral parts must 

 come together from the front and be accreted" (§ 63, p. 460). 



After this description the following "thoughts about 

 epigenesis" are significant. 



I suggest that if the described way of intestine 

 formation is correctly understood, then no doubt can 

 remain of the truth of epigenesis. Because if the 

 intestine, from the beginning, is a simple membrane 

 which is then rolled up; . . .if the flat membrane 

 swells, acquires a cylindrical form, and becomes 

 similar to primary intestine, then I consider 

 it proven that the intestine is doubtlessly thus 

 formed and did not exist previously in an invisible 

 form, ready to appear at the appropriate moment, 

 (pp. 460 - 461) 



77 



