Radium Rays and Cells of Jensens Rat Sarcoma. 483 



six animals being inoculated for each series. They were examined at 

 frequent intervals, and fig. 1 gives in outline one half the actual sizes of the 

 tumours which formed. 



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Fig. 1. 



It will be seen that as a result of irradiation for 30 minutes there is 

 a slower growth of the irradiated than of the untreated tumour. 



When the period of irradiation is increased to 90 minutes, the inoculated 

 material, although apparently increasing in size for some days, was in all 

 cases eventually absorbed in the animal which was simultaneously supporting 

 the growth of the control tumour. Extension of the period of irradiation to 

 three hours ensures the progressive and complete absorption of the tumour 

 cells. There is a close similarity in the action of the /3-rays in retarding or 

 preventing the growth of rat sarcoma tissue to the results recorded for 

 mouse carcinoma by Wedd and Euss in the paper to which reference has 

 been made. 



The Action of Radium Emanation on Tumour Tissue. 

 Preliminary experiments were made by mincing a tumour with a Haaland 

 mincer and adding to it sufficient normal saline for the mixture to flow into 

 a small glass bulb. Eadium emanation was then supplied in a concentration 

 of about 0*5 milHcurie per cubic centimetre. After 32 minutes O'l c.c. of 



