Development, &g., of the Fat-cell. By G. and F. E. Hoggan. 369 



to the periphery, is inaccurate, from the fact that protoplasm and 

 nucleus are always peripheral to any fat-globule within the cell ; 

 and when by excessive distension the nucleus and protoplasm 

 appear like a signet ring, the relation between the two still remains 

 the same, and after absorption of the contained fat the nucleus 

 appears to return to the centre of the cell-substance, as seen in 

 Figs. 7, 8, 9, 10, and 11, although in reality the relationship has 

 never altered throughout the cell life. We have now traced the 

 fat-cell into its fully developed condition, as shown in Fig. 6, and 

 seen that its parent-cell was the wanderhig cell, under which name 

 we of course include white - blood cells, lymph, lymphoid, or 

 lymphatic cells, migratory cells, embryonic cells, leucocytes, 

 amoeboid cells, and to these, by our own showing, the so-called fixed 

 branched cells of the connective tissue and of the adventitia of blood- 

 vessels ; and we have also seen that these cells may be either 

 globular, round, flat, spindle-shaped or branched, according to the 

 position in which they are viewed, or whether they are fixed 

 before or after they have had time to contract or retract their pro- 

 cesses. With the fully developed fat-cell we reach the end of the 

 first half of our studies, a task which ought to have been simple 

 and short, but for the fact that it was encumbered with the diver- 

 gent opinions of diflerent observers. We have endeavoured to 

 reconcile those opinions where possible, by explaining the causes of 

 divergence, and in this, we believe, we have been not unsuccessful. 

 We now pass on to the second part of our studies, to show how 

 the fully develojied fat-cell returns into its original condition of a 

 wandering cell, a task which will prove much easier and interesting 

 than that of following development, for few observers have traced 

 even the first part of the dechne of the fat-cell, and none to our 

 knowledge have witnessed the interesting appearances which herald 

 its disappearance, so that we shall here only require to state the 

 appearances observed by ourselves, and not to reconcile the divergent 

 opinions expressed by others. 



Part II. — Betrogression of tJie Fat-cell. 



During the development of fat-ceUs we noticed that, as the fat 

 increased within the cell, the cell-substance also increased pari passu 

 with the amount of fat which it had to envelope. In absorption or 

 retrogression of the fat-cell, we have thus two substances to get rid 

 of before the cell can return into its original condition ; but although 

 these two substances, namely, fat and excess of cell-substance, de- 

 veloped at the same time, their absorption occurs separately ; indeed 

 the decline or break up of the cell-substance does not commence 

 until some time after the complete disa])pearance of the cell-con- 

 tained flit. 



VOL. II, 2 b 



