SECTION III 

 THE HISTORY OF FAT IN THE BODY 



FAT is found in the body in various situations. In a fat animal 

 the largest amount occurs in the panniculus adiposus in the sub- 

 cutaneous tissues. Large quantities are also found surrounding the 

 abdominal organs and between the layers of the mesentery and great 

 omentum. In this adipose tissue the fat is enclosed within and 

 distends connective-tissue cells, the protoplasm of which is reduced to 

 a thin pellicle round the fat globule. Fat is also found in the form 

 of granules in more highly specialised cells, such as the secreting cells 

 of the liver or the muscle-cells. The condition of these cells is often 

 spoken of as fatty infiltration, or fatty degeneration, according to 

 the circumstances which are responsible for bringing about the 

 deposition of fat. We shall have to discuss later on how far we are 

 justified in assuming any real distinction between these two processes. 

 From the physiological standpoint the most important intracellular 

 depot of fat is in the liver. If this organ be deprived of glycogen and 

 fat by starvation, a fatty meal gives rise to a great deposition of fat 

 in its cells. There is apparently an antagonism between the processes 

 which lead on the one hand to the deposition of glycogen and on the 

 other to the deposition of fat. Thus an excessive carbohydrate diet, 

 which induces great deposition of fat in the subcutaneous tissues, only 

 causes the formation of glycogen in the liver. The glycogen must be 

 got rid of before it is possible to cause the deposition of fat. On this 

 account, the normal content in fat of the livers of different animals 

 varies with their ordinary diet. Fishes, e.g. the cod, which take but 

 little carbohydrate in their food have generally a very large quantity 

 of fat in their livers. Herbivorous animals, as a rule, have practically 

 no fat in the liver. 



Fat also occurs in certain secretions, e.g. the milk and the sebum, 

 its function in the latter case being mainly protective. 



^Besides the visible deposit of fat found in adipose tissue and in 

 other situations a large amount of fat is always present built up into 

 the protoplasm of the c,ells in such a condition that its presence cannot 

 be detected by histological means. The presence or absence of visible 

 fatty globules affords very little clue to the total quantity of fat in the 

 cells. Thus in one case the heart muscle,which had undergone extreme 



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