176 DIVISIONS INDUCED IN LYMPHOCYTES 



proliferation of individual cells, but that of multitudes 

 of them. It is very difficult to believe that the develop- 

 ment of an animal from the ovum can be entirely an 

 automatic function of the protoplasm of individual cells, 

 unless that function is so controlled that the cells act 

 together in masses. Moreover, the phenomenon of 

 healing which has been mentioned presents features 

 which tend to dispose of the "automatic theory" a 

 theory which does not explain why cells immediately 

 reproduce themselves at a much quicker rate than 

 normally when a tissue is damaged. Leucocytes, for 

 instance, will not divide when they are removed from 

 the body, nor have they ever been seen in the act of 

 division when examined from the peripheral circulation. 

 Yet when these cells are shed into a damaged tissue 

 they proliferate immediately. 



Jacques Loeb was, we believe, the first to show that 

 cell-division in the ova of star-fish can be accelerated 

 by certain chemical reagents; and further observations 

 were made in this line of work by B. Moore, H. E. Roaf, 

 and E. Whitley, who proved that the regularity and 

 rapidity of growth of the cells of the fertilised ova of 

 echinoderms could be greatly influenced by certain 

 alterations in the alkalinity of the water in which they 

 normally divide. B. Moore has also shown that the 

 alkalinity of the blood-plasma in cancer is increased 

 a point which is of great importance, especially when 

 we remember that alkalies increase the diffusion of 

 substances into living cells. 



O. and R. Hertwig and Galleoti have described 

 how, when mitosis occurs in some of the cells of 



