170 Dr. Bashford, Mr. Murray, and Dr. Cramer. [Dec. 10, 



negative when propagated in the way he has adopted (large doses and smaller 

 number of animals). 



The following experiments were undertaken because of the difficulties met 

 with in obtaining a positive result in the primary transplantations of 

 spontaneous tumours. It was of importance to determine whether the 

 spontaneously affected animals were more suitable for transplantation, both of 

 their own tumours (on the analogy of metastasis) and of other spontaneous 

 tumours. The difficulty of transplanting many mouse tumours, especially 

 those with extensive haemorrhage, has led observers who had failed to trans- 

 plant them to conclude that those tumours were of low " virulence." We 

 had already succeeded* in three instances where others had failed in trans- 

 planting these hemorrhagic tumours, the daughter tumours being also 

 hemorrhagic, and had observed that they produced extensive metastasis in 

 the animals primarily affected. We were, therefore, of the opinion that it 

 was wrong to conclude from the difficulty of transplantation that they were 

 of low virulence. 



We have prolonged the lives of mice presenting spontaneous tumours by 

 removing the primary growth by operation, wholly or partially. This has 

 permitted us to study their suitability for transplantation, both for their own 

 and for other spontaneous tumours, and to compare it with the suitability of 

 normal animals. 



The opportunities for such experiments are rare. Up to the present 

 13 animals presenting spontaneous tumours have been inoculated with their 

 own and other spontaneous tumours. The results for 11 of these animals are 

 now available, and are as follows : — 



Two mice (XXXI II and XXXIV) could be successfully inoculated with 

 their own tumours, and in the case of one of them (XXXIII) three normal 

 animals also developed tumours out of 97 inoculated and surviving three weeks 

 after inoculation. In the case of the second mouse, her tumour gave negative 

 results in 140 normal animals, although successfully inoculated into herself. 



A third spontaneous tumour (XXXII) gave four tumours in 156 normal 

 animals, was negative in the mouse spontaneously affected, but positive in 

 another mouse (XXXIII) with spontaneous cancer. A fourth spontaneous 

 tumour (XL) inoculated into 49 normal animals, failed to grow and was like- 

 wise negative in two mice with spontaneous cancer (XXXYII and XXXVIII). 

 A fifth spontaneous tumour (XXX) gave one tumour in 72 inoculations into 

 normal animals, but failed to grow in three other mice (XXV, XXVII and 

 XXVIII) spontaneously suffering from cancer, as well as in the mouse herself. 

 Three inoculations were made in each of these four mice. 



* Second Scientific Eeport, 1905, Part II, pp. 19 and 30. 



