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Scientific Proceedings (53). 



the milk-fed and the normal animals in this respect was not so 

 marked as one would be inclined to anticipate if cholesterol were 

 really a prime factor in determining the incidence of carcinoma, 

 and if feeding for two months upon a diet unusually low in choles- 

 terol really brought about any appreciable diminution in the choles- 

 terol-content of the tissues. 



That cholesterol is an important factor in determining the inci- 

 dence of carcinoma can hardly be doubted in view of our previous 

 results, cited above, and of the fact, recently discovered by 

 Wacker, that the cholesterol content of the fatty deposits in the 

 subcutaneous tissues and mesenteries of persons who have car- 

 cinoma is no less than 66 per cent, greater than the cholesterol 

 content of the fatty deposits in normal persons. 1 An increase in 

 the cholesterol content of reserve-fats was also observed by Wacker 

 in aged persons and in persons afflicted with tuberculosis or 

 diabetes. 



Our failure to observe a more striking difference between the 

 incidence of carcinoma in milk-fed and in normal rats we are 

 inclined to attribute to the fact which has been demonstrated by 

 Ellis and Gardner 2 that cholesterol is strictly conserved in the 

 animal economy, since the cholesterol which is excreted in the bile 

 is reabsorbed in the intestine and does not appear in the feces, 

 while, on the other hand, cholesterol contained in the food is in 

 large part absorbed. Hence removing cholesterol from the diet 

 of an animal does not lead to an appreciable removal of cholesterol 

 from the tissues. More conclusive results might be anticipated 

 if animals were fed from the time of birth upon a cholesterol-free 

 diet, since the tissues of newly-born animals contain relatively 

 little cholesterol. 3 Experiments in this direction are being under- 

 taken. 



In conclusion we wish to point out that since the cholesterol 

 in the diet is partly absorbed, while the cholesterol content of the 

 body is strictly conserved, it follows that animals must tend to 

 accumulate cholesterol. We believe that this explains the exces- 

 sive cholesterol content of the reserve fats in aged persons which 



1 L. Wacker, Zeil. f. physiol. Chetn , So (1912), p. 383. 



2 G. W. Ellis and J. A. Gardner, Proc. Roy. Soc. London, 81 B (1909), p. 505. 



3 G. W.Ellis and J. A. Gardner, Proc. Roy. Soc. London, 84 B (1912), p. 461. 



