• ■- -v..--r 









Fig. 29 



Mast cells in tissue culture. Well-granulated mast cells are creeping out from the primary 

 explant, a fragment of dog mastocytoma (bottom R.). Phase contrast photograph, Dr. J. B. 



MacDougall ( X 372). 



* 



Fig. 30 



Isolated mast cell from a primary explant of dog mastocytoma grown 



for six days in tissue culture. Phase contrast photograph, Dr. J. B. 



MacDougall (>:640). 



