AND DIABETES 99 



result of a peculiar abnormal process of breaking 

 down of the fats. 



The physiological process of dealing with fat is to 

 resolve it into carbon dioxide and water. If we 

 make a pound of fat into tallow candles and burn it, 

 we shall obtain carbon dioxide and water, and a 

 certain amount of heat will be evolved. If the pound 

 of fat is eaten and absorbed by a man or an animal, it 

 will be burnt to the same end-products, and the same 

 amount of heat will be given out. But in certain 

 circumstances, an abnormal mode of breaking down 

 is followed, and there are produced first /3-oxybutyric 

 acid, then diacetic acid, and finally acetone. If this 

 takes place on a large scale, the conversion into 

 acetone fails to keep pace with the production of the 

 acids. Therefore first acetone appears in the urine, 

 then diacetic acid, and finally ^-oxybutyric acid ; 

 the last may rise rapidly to an enormous figure ; 30, 

 50, or even 180 grammes may be passed daily in dia- 

 betic coma (Magnus Levy). 



Feeding on fats will always cause some rise in the 

 output of acetone and of these acids if they are already 

 present ; in starvation it will cause a very marked 

 increase. Butter, which contains lower fatty acids 

 (butyric, etc.), as well as fats, is particularly active in 

 this respect. 



It is of no great importance to us to know where 

 in the body this process of breaking down takes place ; 

 the liver is usually supposed to have the power to 

 effect it. 



,We next ask, What are the special circumstances 

 in which the breaking down of fat deviates from 



