602 



ADVEJJiTURES IN JIADIOISOTOPE RESEARCH 



of other experiments by Eheenstein, in which the red corpuscles were 

 labelled in animals with tumours but not in healthy animals, shows that 

 this holds good. The incorporation of the i^C into the erythrocytes is 

 increased fourfold in this case. The mice are able to compensate the 

 curtailment of the life-time of red corpuscles in a quantitative manner 

 by means of increased bone-marrow and spleen function. The cancer 

 patient also usually shows a similar compensation. Mostly, of course, 

 this is an incomplete compensation. We shall return to this question 

 later. 



o Concer 

 • Control 



Fig. 4. Life-time of red corpuscles labelled in a mouse with 

 carcinoma and in a normal mouse. 



Figure 4 also shows that a portion of the erythrocytes formed in the 

 animal having carcinoma decays rapidly, from which we may conclude 

 that, apart from the extracorpuscular action to which the red corpuscles 

 are exposed in the tumourous animal, abnormal erythrocytes are also 

 formed to some extent in such an animal. 



The extracorpuscular damage to the erythrocytes must clearly be 

 attributed primarily to a plasma factor or to activation of the reticulo- 

 endothelial system. Haemolysing substances have often been observed 

 to exist in tumours. It has also been found^^*^ that the volume of the 

 individual erythrocyte undergoes an increase due to the action of the 

 plasma of a cancer patient; a volume increase initiates haemolysis. 

 A range of enzymes are present in enhanced concentration in the plasma 

 of a cancerous organism. Warburg and Christian^^^' '^^' ^3) and others 

 observed a marked enhancement of the aldolase content in plasma when 

 large tumours existed. One in four of the cancer patients studied, was 



