Develoj^ment, &c., of the Fat-cell. By Q. and F. E. Eoggan. 371 



pyrogallate of iron. It may be taken as a typical specimen of 

 steady and unbroken absorption of fat from fat-cells, and it will be 

 noticed that, owing to the locality and the absence of distorting 

 pressure from neighbouring cells, as well as from their lying 

 parallel to the surface, all the cells are assuming the oval, almond- 

 like shape. 



Fig. 8, again, is from the subcutaneous tissue of the body of a 

 young man, who died after an illness of thirteen years and in the 

 last stage of leprosy. It is prepared by treatment with osmic 

 acid and picro-carminate of ammonia. It represents a more 

 advanced condition of fat-absorption than that seen in Fig. 7 ; 

 and although selected from a spot in a perpendicular section, 

 where the fat-cells were by no means closely packed, yet evi- 

 dence of distortion (rapidly disappearing, it is true) is to be 

 seen in the angular shape of one or two of the cells. At other 

 parts of the group not included in the drawing, many fat-cells were 

 seen entirely destitute of fat. In neither case had the disease 

 under which the patients sufliered aifected in any way the flit-cells. 

 Although some observers have tried to make out a distinction 

 between the fat-cells found under the skin and those found in 

 serous membranes, recommending only the former for examination, 

 yet it will be seen that the fat-cells in Fig. 8 only differ from those 

 in Fig. 7 inasmuch as the former have been distorted by pressure 

 of contiguous structures, while the latter show the normal and true 

 shape of the fat-cells. Fig. 9, from the broad Hgament of the 

 mouse formerly referred to, shows a still further stage of absorp- 

 tion of fat, which has entirely disappeared from several of the 

 cells c, c in the drawing. Some of these cells also have been exposed 

 to some slight distorting pressure, and it will be specially observed 

 that in general appearance they are identical with the fat-cells of 

 the human body, as seen in Fig. 7, they having been prepared by 

 the same process. 



Certain observers have also stated that the difference between 

 the fat-cells in man and the smaller mammals was so great, that 

 the latter could not be taken as types of the former. To this 

 statement we wish to give a complete denial ; we have never been 

 able to detect any difference whatever, not even sufficient to enable 

 us to tell which animal they belonged to. 



As from several of the cells shown in Fig. 9 the fat has com- 

 pletely disappeared, we may consider that in them we have reached 

 the end of the first stage in the retrogression of the fat-cell, that, 

 namely, which concerns the absorption of fat only; so before 

 passing on to the second stage, let us make a few remarks relative 

 to fat-absorption. 



We find no reason to suppose that the different stages seen in 

 the development of fat are represented in its absorption. We saw, 



2 B 2 



