Bevelopment, Jtc, of the Fat-cell. By G. and F. E. Hoggan 361 



ever a wandering cell is about to become a fat-cell, it develops a 

 considerable amount of protoplasm or cell-substance proper, which 

 increases likewise 2^(^'^'i ^assu with the growth of the fat within it, 

 so as to form a strong envelope for the great globe of fat in 

 the fully developed fat-cell. 



Wandering cells, therefore, like e and / and especially a, with a 

 comparatively large amount of protoplasm, although apparently 

 round when viewed from the front, are also flat, and when viewed 

 edgeways they appear like long or spindle-shaped cells, thus causing 

 and accounting for a certain amount of confusion in the views and 

 descriptions of different observers ; for in the thick subcutaneous 

 tissue (unlike this thin membrane) in which it has been recommended 

 to study the development of fat-cells, these cells are seen as often 

 edgeways as any other way. 



If we have succeeded in showing that fat-cells are developed 

 from wandering cells, and that the hastily assumed difference 

 between globular and flat round cells gives no ground for supposing 

 that the progenitors of the fat-cell were special even from their 

 origin, and if we have also succeeded in reconciling the views of 

 Eollett, lianvier, Czajewicz, and others, who have held respectively 

 that fat-cells were developed from flat and from round cells, are 

 we therefore to hold that Flemming and others, who have insisted 

 that fat was developed in branched cells, are wrong in their views ? 

 By no means ; and we hope to be able to show that they also 

 are correct, and that perhaps the chief cause of disagreement be- 

 tween observers lies in the fact that, by different methods or modi- 

 fications in methods of preparation, the same elements were shown in 

 all the different forms referred to. Even at the risk of appearing 

 prolix, we shall point out how slight modifications in preparation 

 have changed our views slightly, and appear to justify the opposite 

 opinions held by different observers. 



When we tirst commenced this research some years ago, we were 

 careful to bleed the animal to death, after making it insensible by 

 chloroform, and after the blood had been withdrawn as much as 

 possible, the blood-vessels were filled with a coloured injection, and 

 the body was left to cool before we opened it to procure the membranes 

 for our preparations. In this way the preparations from which 

 Figs. 1, 2, and 4 were drawn, were made, and we believed that fat- 

 cells were specially developed from round or flattened wandering 

 cells. Some time afterwards, being in a hurry, we dispensed with 

 the preliminary bleeding, injecting, and cooling, and found that 

 we thus obtained singularly beautiful and illustrative specimens, 

 especially when the animal had been drenched with chloroform 

 after it was insensible. The vessels were still distended by fluid 

 blood, and all the wandering cells within the membrane were 

 found in a more or less branched condition, even when a large 



