174 



Dr. Bashford, Mr. Murray, and Dr. Cramer. [Dec. ] 0, 



During the continued propagation of Jensen's tumour in the last three 

 years, series of inoculations have been obtained repeatedly with maximal 

 percentage of success. The method of repeated subdivision of the 

 parenchyma into the small grafts necessary for the analysis of growth, showed 

 that each such maximum was followed by a rapid and great diminution in the 

 percentage of success, on which again an increase ensued, till a fresh 

 maximum was encountered. The complication which these fluctuations 

 introduce has been in great part avoided in the following way. 



By choosing a suitable interval for inoculation of tumours selected from 

 series with from 90 to 100 per cent, of success, and especially by increasing the 



Graphic Record of Propagation through ten Passages of a single Strain of Jensen's 

 Carcinoma in which success has not fallen below 85 per cent. 



initial dose introduced into each animal from O'Ol to - 05 gramme, we have 

 been able to evade the diminution usually following each maximum for a 

 considerable number of transferences. This result is artificial. It does not 

 indicate an increased " virulence " of the tumour cells, or a continuous growth 

 of uniform energy on their part. It is in complete harmony with the results 

 of the experimental analysis of the growth of cancer as we have already 

 described it. 



In the case of other tumours we have obtained the same result in the same 

 way, but most speedily in the case of spontaneous tumour XXVII, which at 

 the third transplantation gave 80 per cent, of successful inoculations, and at 

 the fifth 98 per cent., the success of the primary transplantation being only 

 20 per cent. 



Separate strains of Jensen's tumour have been propagated, as indicated in 



