THE HUMAN EMBRYO AT EIGHT WEEKS 



281 



Fig. 188. The human fetus 

 about two months after fertilization. 

 (From Julius Kollman, Handatlas 

 der Entwicklungsgescbichte des 

 Menschen. Verlag von Gustav 

 Fischer, Jena.) 



muscle can be demonstrated by stimulating regions above the spinal cord 

 posterior to the forelimb and obtaining a typical forelimb twitch. This ex- 

 periment shows that the transmission along the cord and across a synapse in 

 the motor region of the cord opposite the limb must be complete. 



The human embryo at eight weeks 



The general appearance of an eight-week embryo changes in the direc- 

 tion of a fetus by becoming more recognizable as a human. Facial features 



