Referring to Wolff's work, Tredern said that the 

 intestine is formed of the mesentery (61) , On the sixth day, 

 part of the intestinal canal forms something like a loop 

 (Figure 18, 20(5)), which is designated as the blind 

 intestine (Figure 18, 20(8)}. When other parts of the digestive 

 tract are already distinguishable to the naked eye, this loop 

 thrusts out a little bit from the abdominal cavity 

 (Figure 18, 21(7)). It is more clearly seen on the eleventh 

 day, when the size of the intestines increases (62) 

 (Figure 18, 22(12)). From the sixteenth day the loop starts 

 to extend into the abdominal cavity, and this process ends 

 by the nineteenth day. During this time all parts of the 

 digestive canal acquire a defined shape. 



This section of the dissertation ends with observations 

 characteristic of the entire work. 



EXTREMITIES OF THE WINGS AND LEGS. Tredern began 

 by giving credit to Wolff, who had given the first and 

 undoubtedly the best description of the early stages of 

 development of the extremities. Tredern indicated that his 

 own data were only a confirmation of Wolff's. Noting the 

 different opinions of different authors concerning the time 

 of appearance of the extremities (63) , Tredern gave the 

 following description of their development. On the second 

 and third days in that place where the extremities appear, 

 cellular material accumulates. By the end of the second or 

 the beginning of the third day, suddenly and perfectly 

 distinctly, the foundation of the extremities appears, so 

 that on the fourth day they have the shape of sacs (Figure 18, 

 3(9 - 10)) as though filled with a transparent material, in 

 which no structure can be seen. On the fifth day, the central 

 part of this foundation becomes whitish and much wider than 

 before; there is a white cartilaginous material which is 

 divided in separate parts. From the sixth day it is possible 

 to see fingers, composed of this same transparent material, 

 which cover the extremity in the form of a glove (Figure 18, 

 11(10 - 11)) C64) . A drawing illustrates the fingers of a 

 goose embryo at the eighth day of incubation. In the chick 

 embryo at the eighth day, the joints appear distinctly. On 

 the tenth or eleventh day, the transparent material covering 

 the fingers starts to move toward their tips, and something 

 like the swimming web is formed, which on the twelfth and 



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