220 



Dr. Bashford and Messrs. Murray and Bo wen. [May 30, 



three subsequent occasions. The tissue obtained at these operations was 

 transplanted under the same experimental conditions. From the implantations 

 after the first operation fifteen tumours developed in the 75 mice remaining 

 alive 10 days after implantation. Nine of these tumours were used for 



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2C 









20 

 1f 



L 











10 







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S 





2A 



* 













CM ni 





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Fig. 11. — Graphic record of propagation of a sporadic mouse tumour XIX. Com- 

 mencing at 20 per cent, the transplantability gradually diminished through 

 three successive transplantations till negative results were obtained. The 

 tumour was removed by operation in the first instance, and recurred three 

 times. The results of transplanting the material obtained at these three later 

 operations are indicated also on the chart at * 5 per cent., ** per cent., and 

 *** per cent. 



transplantation. The other six grew for a time, attaining an approximate 

 weight of - 5 gramme, then remained stationary, and were ultimately com- 

 pletely absorbed. The histological features of spontaneous absorption were 

 identical with those already alluded to. One tumour developed in the 50 mice 

 alive 10 days after inoculation with the material from the second operation. 

 Negative results were obtained with material from the other two operations, 

 81 implantations having been made in each instance. When the mouse died 

 three months after the first operation the left pleura and right lung were 

 found filled with metastatic deposits. Thus growth proceeded in the animal 

 primarily affected, and at the same time ceased in the animals inoculated 

 succesfully, either after a transitory proliferation in one animal or in 

 succeeding transplantations. Portions of the growth removed at subsequent 

 operations did not exhibit the same proliferative energy, when transplanted, 

 as those obtained at the first operation. We wish to draw attention to the 

 similarity of behaviour of this sporadic growth at different times with the 

 behaviour of single strains of Jensen's tumour in which cessation of growth 



