898 PHYSIOLOGY 



Accepting this generalisation, the chemical mechanism by which 

 fats are converted into carbohydrates must be the reverse of that 

 by which carbohydrates are changed into fats. The 2-carbon group 

 split off from the large fatty molecules are probably utilised for the 

 building up of the sugar molecule. We know that such a synthesis 

 can take place from such simple groups as formic, glycollic, or glyceric 

 aldehyde. Though it is impossible to deny to any cell of the body the 

 power of effecting the conversion of fats into carbohydrates, or carbo- 

 hydrates into fats, the chief centre for such conversions is probably 

 the chemical factory of the body, namely, the liver. It is significant 

 that in the course of fatal diabetes, in which the fat disappears entirely 

 from the body, and there is wasting of practically all the tissues, 

 the liver is the only organ which retains its weight unchanged. During 

 this disease there has been an enormous amount of work done in the 

 conversion of proteins and possibly of fats into carbohydrates which 

 could not be utilised by the body, and the large size of the liver at 

 death suggests that the work of transformation has been performed 

 by this organ. 



