THE METABOLISM OF FAT 



283 



the glycerine of the fat is not used for this synthesis, but 

 for the production of energy, which is required for the syn- 

 thesis. That the mucosa can supply glycerine is shown by the 

 fact that fatty acids when fed alone can be synthesised into 

 neutral fat. The neutral fat passes by the chyle into the blood, 

 and is there changed into an unknown soluble, filtrable, dialy sable 

 modification, and passes in this state through the capillary wall 

 into the tissue. Herein the process is reversed, neutral fat 

 synthesised and laid down as depot fat. 



Many micro-organisms (mostly aerobic) have the power of split- 

 ting fat. Bacterium Coli, for example, can split milk fat up to 

 6 2 7 per cent. Mucor-like moulds, when growing on cheese or 

 butter, can increase the fatty acid value in the ether extract from 

 2- 7 to 47'7. No glycerine is found, so probably it is used by 

 the moulds as a source of energy. The expressed juice of such 

 moulds has a lipolytic action. 



In the seeds of oil fruits the fat acts as a reserve food supply, 

 and on germination is split by a lipase, and rapidly diminishes. 



THE METABOLISM OF FAT 



The body of an adult man who has lived on an average 

 maintenance diet consists of about 60 per cent, water and 40 

 per cent, dry matter; about 18 per cent, of the latter is fat. 

 The difference between fat and lean animals is shown by the 

 following : 



While the total percentage of water is very markedly lowered 

 in fat animals, the percentage in the actual living tissue, excluding 



