1906.] Experimental Analysis of the Growth of Cancer. 203 



43 survivors (30 per cent.), 43 L. One of these, 21 days later, had attained 

 a weight of 3 - 3 grammes and was transplanted into 27 mice ; tumours 

 developed in 8 of the 15 survivors (53 per cent.), 44 D. After 22 days' 

 growth, one of these, 3 - 7 grammes weight, was transplanted into 55 mice ; 

 tumours developed in 17 of the 32 survivors (53 per cent.), 45 C. After 

 26 days a tumour 1 gramme in weight was transplanted into 40 mice ; 

 tumours developed in 21 of the 32 survivors (66 per cent.), 46 G. After 

 15 days' growth, a tumour weighing 1'3 grammes was transplanted into 

 40 mice, tumours developing in 26 of the 33 survivors (79 per cent.), 47 H. 

 After 14 days a tumour weighing 1'35 grammes was transplanted into 

 30 mice, tumours developing in 21 out of 25 survivors (84 per cent.), 48 E. 

 Up to this stage there has been a gradual rise in percentage of success 

 through nine successive transplantations from 15 to .84 per cent. The 

 results of transplanting seven tumours of Series 48 E do not maintain 

 this high percentage. Thus a tumour of nine days' growth, weighing 

 T15 grammes, was transplanted into 54 mice, tumours developing in 9 

 out of 32 survivors (28 per cent.), 49 A. Another, 11 days' growth and 

 1*7 grammes in weight, was transplanted into 40 mice; tumours developed 

 in 12 out of 38 survivors (33 per cent.), 49 B. A third, also 11 days' growth, 

 weighing l - 4 grammes was transplanted into 31 mice ; tumours developed in 

 10 out of 27 survivors (37 per cent.), 49 C. A fourth, of 15 days' growth, 

 17 grammes in weight, was transplanted into 40 mice ; tumours developed in 

 12 of the 35 survivors (34 per cent.), 49 F. A fifth, of 26 days' growth, 

 3 - 2 grammes in weight, was made into an emulsion and injected into six mice. 

 All the mice survived, but no tumours developed, and this experiment is not 

 recorded on the chart below. A sixth, of 27 days' growth, 3 - 6 grammes in 

 weight, was transplanted into 41 mice and tumours developed in 5 out of 

 25 survivors (20 per cent.), 49 O. A seventh, after 62 days' growth, weighed 

 3 grammes. It was transplanted into 40 mice ; tumours developed in 20 out 

 of 36 survivors (56 per cent.), 49 X. None of these tumours maintained the 

 high transplantability of the parent growth, although the implantations grew 

 rapidly and were made at intervals of from 9 to 62 days. This sequence in 

 the results has been a constant feature in all the strains propagated, and 

 there is, therefore, reasonable ground for believing that it is a natural 

 feature of growth. 



We shall now proceed to a consideration of the graphic records of this 

 series of experiments. In the accompanying chart (fig. 2) the lines joining 

 the points representing the date of transplantation and power of proliferation 

 appear to form a continuous ascending curve rising from 40 I (15 per cent.) 

 through nine successive transplantations to 48 E (84 per cent.). 



R 2 



