THE GENERAL CONDITIONS OF LIFE 331 



metamorphosis, mucous degeneration, amyloid degeneration, and calci- 

 fication. 



To consider first the phenomena of fat-metamorphosis, we must 

 avoid confounding these with apparently similar processes, viz., 

 the deposition of tat or fatty infiltration in fattening, obesity, etc. 

 In these latter also there is a great accumulation of fat in the cells 

 in question, but this fat has not arisen by a disturbance of the 

 metabolism of the cells themselves ; on the contrary, it or its con- 

 stituents has entered into the cells from the outside and has there 

 been deposited. If much fat or materials from which fat can be 

 formed be introduced into the body in the food, such fat becomes 

 deposited by preference in certain parts within the cells, as in the 

 cells of the subcutaneous connective tissue, and thus arises 

 corpulency, the panniculus adiposus. Of course it is not 

 impossible that in many cases of corpulency fat arising pathologi- 

 cally within the body also enters into the cells of the subcutaneous 

 connective tissue and is there deposited. But even here there is 

 always a fatty infiltration of the cells from the outside. In 

 contrast to this, in fat-metamorphosis fat is formed within the cell 

 itself at the expense of its living substance, and there accumulates 

 until the cell is permeated with innumerable, large or small 

 proplets and dies. Such fat-metamorphosis, which ends with the 

 death and disintegration of the cell, occurs in certain places in the 

 healthy body as a normal phenomenon ; thus, it is present in the cells 

 of the lacteal glands at a time when they are secreting milk, when 

 a woman is nursing. It is found that at this time in the lobes 

 of the mammary glands microscopic fat-droplets ajDpear in the 

 protoplasm of the older cells (Fig. 144); these gradually increase 

 in number, while the protoplasm gradually dies, and the cell 

 finally becomes a round droplet, full of small milk-globules. The 

 dying protoplasm gradually disintegrates, the fat-globules become 

 free, and the whole mass, i.e., the fat-globules in their liquid, 

 becomes secreted as milk, milk being nothing more than an 

 emulsion of the fat of butter in a solution of salts, proteids, 

 sugar, etc. The younger gland-cells succeed the older, fatt}-- 

 degenerated and disintegrated cells, and pass through the same 

 changes, and thus the process of milk-formation continues long 

 and uninterruptedly. What occurs as a normal process in the 

 cells of the lacteal glands occurs under pathological con- 

 ditions in much greater extent in very various tissues, and leads 

 almost always to incurable and fatal losses, since as a rule no 

 reparation is made by the younger cells. " The production of 

 milk," says Virchow ('71), "in the brain instead of in the lacteal 

 glands, constitutes a form of brain-softening. The same process 

 that in one place affords the happiest and sweetest results, in 

 another induces a painful and bitter wound." Such fatty 

 degenerations appear especially in long-continuing, chronic 



