Immunity of Rats toivards Jensens Rat Sarcoma. 15 



Table IV. 





No. of rats 

 inoculated. 



Average superficial 

 area at the 

 14tli day. 



Average superficial 

 area at the 

 21st day. 





33 

 20 

 45 



sq. mm. 

 189 

 135 

 63 



sq. mm. 

 270 

 186 

 117 



Tumour with normal rats' spleen . , . 

 Tumour with immune rats' spleen 



This deterrent effect of the spleen of immunised rats upon tumour growth 

 is not to be attributed to any immunity which might be eventually produced 

 by the spleen cells. This was shown by inoculating tumour on one side of 

 the rat and spleen on the other ; no appreciable effect upon tumour growth 

 was observed. 



7 20 z^om^ 7 /4 2o asms 



Fig. 10. — A. Tumoui' only ; B. Tumour + Normal spleen ; C. and D. Tumour + Immune spleen. 



