374 Transactions of the Society. 



and vessels which had developed ^;ari 2^<^ssu with the outlying 

 groups of developing fat-cells, as indeed the special nutritive adjuncts 

 of the latter, have no longer any raison d'etre when their nurslings 

 perish, and they consequently obliterate their canal, and the con- 

 stituent cells separate and undergo a similar granular exodus to 

 that seen in the retrograding fat-cells, although in a much smaller 

 and otherwise almost imperceptible degree, as at/,/. 



During the process of granular exodus in the fat-cell, a change 

 was taking place in the condition of the nucleus, which only becomes 

 apparent when, as shown in cell h, the greater part of the granules 

 which obscured the nucleus have left and allowed the nucleus to 

 become visible. 



In the wandering cell, the nucleus stains intensely by colouring 

 agents, and is generally more or less globular in shape, except when 

 proliferating. When the wandering cell becomes a fat-cell, we see 

 that, as the protoplasm becomes distended by the fat within, the 

 nucleus also seems to become stretched out into a flat circular or 

 oval form, being thinner if greater in superficies, and staining much 

 less intensely than formerly by staining agents. Even in retro- 

 gression the nucleus maintains its flat and circular condition, as it 

 seems to pass back to a position in the centre of the cell-substance, 

 and continues in that condition till the granular exodus obscures 

 it. When it next appears, as in cell h, it has become globular, and 

 smaller in superiicies, and begins to stain more intensely, comes 

 back indeed to the condition of the nucleus of the wandering cell, 

 so that no distinction can be made between them. 



The point of greatest importance in this inquiry is the nature 

 or character of those granules which we see leaving the cells and 

 travelling through the gelatinous matrix of the membrane, appa- 

 rently by virtue of their own power of locomotion. Indeed the 

 end of these studies only opens out to us the commencement of 

 other more minute, more delicate, and more important researches. 

 What, in the first place, is the tj'pical shape of the granules ? The 

 powers of the Microscope used in making the drawings 800 diameters, 

 only showed them as bright refringent points, staining slightly by 

 the black staining fluid used in the cases mentioned. 



Moreover, to be able to fix their natural shape, they ought to 

 be studied in their living condition, upon the warm stage under the 

 Microscope, to see if, like wandering cells, they alter their shape 

 during life or during theu' locomotion, if such can be observed. 

 Even during their dead condition (chloroform having been plenti- 

 fully used in killing the animal, so that we might hope that, like 

 the wandering cells, they were fixed in their living shape), with 

 specially high powers of the Microscope, we can see that many of 

 them are oblong in shape but round when seen edgeways, and 

 sometimes two or three are attached together like beads. All these 



