The Organization of the Egg 



199 



in cancer, certain cells possess the power of seemingly un- 

 limited growth, increasing at the expense of other tissues, 

 running wild within the body, and finally destroying it as a 

 result of their riotous living. This power of seemingly un- 

 limited growth of the cell may in many cases be initiated 

 artificially. 



Unquestionably the most important of Harrison's results 



A PIECE OF GROWING TISSUE 



The dark center is the original tissue, the branching bodies radiating 

 out from it are the growing cells. It has been possible to cultivate in 

 glass cells many different kinds of tissue, including those from man 

 himself. This method has been used for studying the growth and 

 reaction of cancer cells, and may throw light on the cause of this dread 

 malady. After Lambert and Hanes, "Journal of Experimental Medi- 

 cine," Vol. 13. 



on nerve growth was his development of the method of grow- 

 ing tissues outside of the animal body. He transplanted bits 

 of the central nervous system of the tadpole to drops of 

 coagulable lymph from the frog, and by placing these in a 

 glass cell under the microscope, he was able to follow the 

 growth of the nerve fibers. More recently a large number 

 of workers, mostly Americans, have developed Harrison's 

 method and applied it to both embryonic and adult tissues 

 of birds and mammals. The method has been applied to the 



