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



animals, including rabbits, guinea-pigs, rats, and mice against mouse tissues 

 (liver, kidney, testis) and tumour, all of which had been freed from blood by 

 washing out the circulation with normal saline, and ground to a fine powder 

 at the temperature of liquid air. The results were unsatisfactory, apart from 

 the exhibition of a distinct specific hsemolytic action on the erythrocytes of 

 mice on the part of the serum of animals immunised against each of the 

 blood-free tissues and a precipitin reaction with mouse serum. In particular, 

 no satisfactory evidence of a specific action on the living cells of mouse 

 tumours could be obtained either in the test-tube or in the body. 



We were led to investigate more fully the effects of the absorption of 

 mouse blood on normal mice, not only because of the difficulty of working 

 with the other tissues, but because of the following considerations : Haemor- 

 rhage is frequent in the process of absorption of tumours after exposure to 

 radium, and during spontaneous absorption. A number of hemorrhagic 

 tumours successfully transplanted in the first instance were found to be 

 peculiarly liable to spontaneous absorption, and in their case the condition 

 was comparable to what is now well known to occur in human chorion- 

 epithelioma. In this connection, we are indebted to Dr. J. H. Teacher for 

 drawing our attention, early in 1905, to the frequency of the spontaneous 

 disappearance of the metastatic growths of chorion-epithelioma and their 

 hemorrhagic character. It was found that an injection of 0*3 to 0*5 c.c. of 

 defibrinated normal mouse blood induced a definite refractory condition, even 

 in young animals. It is not so marked four days after injection as at 10 days, 

 and persists for at least three weeks. The repetition of the blood injection 

 after 10 days does not markedly increase the refractory condition. The animals 

 thus protected do not ultimately develop tumours when observed during a 

 period of three months. 



Protocol to Illustrate Protection Conferred by a Preceding Injection of 



Normal Mouse Blood. 



Experiment 61 T. Sixteen mice received an injection of 0*3 c.c. of normal defibrinated 

 mouse blood on the back. Five days later they were inoculated in the right axilla with 

 O'Ol to 0*02 gramme of a tumour of transplantation 60, Series ii P. All the mice survived, 

 and seven presented tumours after 10 days (44 per cent.). At the same time 30 normal 

 mice were inoculated with the same doses of the same tumour, also in the right axilla. 

 Of the 26 animals surviving after 10 days, 19 presented tumours (73 per cent.). The 

 tumours in normal animals were throughout larger than those in the mice previously 

 treated with blood. 



Experiment 62 Q. Twenty-eight mice received 0*3 c.c. normal defibrinated mouse 

 blood on the back. Eleven days later they were inoculated in the right axilla with 

 0'01 to 0*02 gramme of a tumour of transplantation 61, Series S. Three tumours developed 

 in the 15 animals surviving after 10 days (20 per cent.). At the same time 30 normal 

 animals were inoculated in the same place with the same dose of the same tumour. All 



