1906.] Experimental Analysis of the Growth of Cancer. 217 



behaviour. They are as clean experiments as those with high percentage, 

 and must be included in an objective consideration of the energy of growth 

 of the tumour as measured by percentage of success. Kecording the results 

 by the average percentage of all the series in each transplantation therefore 

 obscures the behaviour of individual strains and fails to reveal the composite 

 nature of this apparently continuous proliferation. 



in each transplantation. 



0. 



P. 





E. 



S. 



T. 



U. 



V. 



W. 



X. 



Y. 



Z. 



Aii. 



Bii. 



Cii. 



Dii. 



Eii. 



Fii. 



Gii. 



Hii. 



Iii. 



Jii. 



— 



— 



21 



33 



— 



— 



50 

































40 



18 



5 



28 



30 



20 



14 



7 



25 



25 



33 

























17 



— 



9 



20 



— 



13 



14 



27 



— 



— 



5 



30 

























25 



















































oo 





































3 



17 



7 







5 



52 



25 



24 





























44 



7 



35 



6 



31 



16 





8 































32 



19 



8 



8 



14 





35 



13 































9 





67 



2 





33 



15 



30 





8 



























19 



37 



10 



14 



30 



24 



47 











33 



18 



33 







18 



33 



8 





28 





21 



9 





33 



27 



67 







10 







43 



27 





















40 



42 



4 



50 



18 



29 



15 



38 































20 



20 



36 



35 



59 



40 



25 



13 



15 



9 



26 



41 























39 



18 



13 



9 



3 









59 



20 





6 























15 



6 



24 









































13 













































69 



61 





33 



34 



6 



7 



46 



65 





























18 





50 





37 



67 



30 



32 



22 



36 



10 



71 



18 



12 



23 

















20 



39 





68 



73 



40 



74 



36 



37 



56 



39 



44 

























15 



37 



57 



6 



59 



59 



15 



15 



37 



53 



90 



40 



14 



77 



19 



31 













70 



29 



64 







60 



68 



12 



13 



19 



45 



35 



21 



53 





22 





28 



25 





8 



7 



32 





33 



43 



56 



8 



33 



14 



80 



25 





12 



50 



57 



42 



31 



40 





20 



53 



7 





47 



16 



30 



13 



11 



19 



63 



66 







10 



43 



8 









59 



44 



80 





33 



15 









40 







25 

































were necrotic on naked-eye examination. 



In the above table the average percentage for each transplantation and 

 the percentage of success for each series are tabulated in numerical and in 

 alphabetical order. Since high percentages were obtained in early trans- 

 plantations, the apparently progessive increase in the percentage of success 

 in later ones cannot be regarded as indicating a permanent alteration in the 

 powers of growth of the parenchyma cells as a result of the number of 

 passages from animal to animal. The error of such an interpretation is 

 demonstrated by a consideration of the accompanying chart (fig. 9), which 

 VOL. lxxviii. — B. s 



