212 METAMORPHOSIS OF TISSUE. 



which are derived from the albuminates introduced into the 

 organism with the food, as long as these are supplied in sufficient 

 quantity. When the organism does not find in the food sufficient 

 materials to form the investing membranes of the fat-cells, it 

 borrows from the muscular fibre the substance with which it sur- 

 rounds the fat in these protein-capsules. When this source of 

 materials for cell-formation is no longer sufficient, the fat begins 

 to accumulate in the blood and other animal fluids. These results 

 were deduced by Persoz and Boussingault,* from a series of most 

 carefully conducted observations on animals which were being 

 fattened. A similar series of metamorphoses may be frequently 

 observed in different morbid conditions ; all the stages induced 

 from excess of fat may be traced in the bodies of drunkards, for 

 here a large amount of material forming fat is, as a general rule, 

 introduced into the body, with only a very small quantity of sub- 

 stance that can be applied to the formation of cells ; and in the 

 artificial fattening of animals, the fat has the greatest tendency to 

 collect in cells that are already formed, as for instance, in the liver, 

 and this gives rise to what is termed the fatty liver a morbid 

 change which induces a certain group of disturbances. In short, 

 we see that the fat, even considered from this point of view, stands 

 in the closest relation to the formation of cells. 



Whilst in the above-mentioned cases fat gives occasion to the 

 formation of cells in the animal body, we see a tendency to the 

 accumulation or new formation of fat in existing cells and tissues 

 whose nutrition has been to a certain extent altered (see vol. i., 

 p. 268). This tendency is most clearly manifested in those 

 pathologico- anatomical cases which have been commonly known 

 under the name of fatty degeneration. These frequently occurring 

 phenomena may be interpreted in two different ways ; for it may 

 be assumed, either that the fat which is already present may be 

 disposed by certain molecular forces to accumulate in the older 

 and less vitally active cells, where it replaces the disappearing nitro- 

 genous tissues ; or that the fat arises directly from the nitrogenous 

 substrata of the cells or fibres, and that their nitrogen disappears 

 under the form of ammoniacal salts or other simple combinations, 

 leaving fat as the secondary product of the decomposition of 

 albuminous matter. 



It must be observed, in reference to the latter hypothesis, that 

 hitherto all attempts made to convert protein-bodies into true fat 

 by chemical means have proved unsuccessful, although there is 

 * Ann. de China, et de Phys. 3me S^r. T. 14, p. 413-435. 



