Development, &c., of tlie Fat-cell. By G. and F. E. Eoggan. 375 



points, however, ought to come into a special inquiry into their 

 life-history, so that we have considered it advisable at present 

 merely to draw them in their general positions, shape, and size, as 

 seen under the power used in making aU the drawings in this 

 research. 



But of far greater importance than their shape is the character 

 of the substance composing these granular bodies, and this, we 

 think, we have been able to ascertain satisfactorily, as far as their 

 biological character is concerned. 



As may well be conceived, the first point of importance to 

 settle was whether these were fatty or protoplasmic in their nature. 

 If, as was Hkely, they were fat-granules, little importance was to 

 be attached to them ; but if, on the contrary, they were proto- 

 plasmic in character, they were all-important as a key to the past 

 and an explanation of the future. 



To decide this point we had to vary our methods of preparation 

 and, instead of using the pyrogallate of iron, we treated our mem- 

 branes with ether, logwood, carmine, indigo, purpurine, and eosine, 

 with and without osmic acid, and the result was unmistakable. 

 Osmic acid did not blacken, while colouring agents stained, logwood 

 being prominent among the rest in the intensity of its staining, 

 showing that these granules were protoplasmic in character and 

 not fatty. 



The character stamped upon them by staining tests, as well as 

 the power they appeared to possess of mo\ing off at pleasure from 

 the parent-cells by their own inherent power, and as we shall 

 afterwards see of probably moving back again when the conditions 

 were reversed, show us that we have here to do with something 

 specific in biology, something vastly more minute, and a stage more 

 elementary than the composite body called a cell ; something which 

 lives and moves and has its being independently of the cell, and to 

 which we are called upon to assign a specific sphere in nature. 

 Have we here germs, the micrococci, the zoogloea, the spores, fungi, 

 bacteria, or the spores from which bacteria are developed in these 

 living atoms ? It is impossible to evade the conclusion that had 

 these been observed in sections of tissues, where their connection 

 with the cell or its nucleus could not be traced, more especially in 

 any specific disease, they would indubitably have been ascribed to 

 some of the foregoing classes, and (perhaps not without reason) the 

 most serious conclusions might be drawn from their presence. We 

 have no doubt that they furnish a key to the alleged discoveries 

 of some of the above-named classes of organisms in certain specific 

 or infective diseases in the past, and they may probably furnish 

 an explanation of many infective processes in the future. 



We may also mention here, with reference to a recent biological 

 mistake in the character of germs that, whether treated with or 



