REACTION OF EMBRYONIC CELLS TO SOLIDS 539 



13 ^4 



Fig. 13 Experiment C 19. Piece of telencephalon of five-day chick embryo 

 cultivated two days in clotted plasma, showing fringe of nerve fibers growing out 

 into clot. X 39. 



Fig. 14 Experiment C 15 Piece of telencephalon of five-day chick embryo 

 cultivated two days in defibrinated serum. X 39. 



In the fourth case (fig. 11), which was cultivated in a large drop 

 where the tissue never was in contact with the cover glass, there 

 are no evidences of cell wandering whatever. The tissue is 

 rounded off and has an almost smooth contour. 



One series of experiments was made to test the effect of the 

 different kinds of support upon the growth of nerve fibers. 

 Pieces of the telencephalon of a five-day embryo were used and 

 twelve cultures were made, four of each kind, in a large drop, 

 on spider web and in clotted plasma respectively. Those mounted 

 in the plasma clot all showed the development of nerve fibers 

 one day after explantation. In the more favorable cases they 

 formed a veritable fringe around the whole periphery of the 

 specimen. The fibers were much matted together and some were 

 branched (fig. 13). Neither the preparations on web nor those 



