THE FATS. 211 



remains of the decomposition of albumen or glutin ; and, on several 

 grounds, it might even be supposed that these matters have been 

 formed from the products of the simultaneous decomposition of 

 nitrogenous and non-nitrogenous bodies. The result of these con- 

 siderations and of all the attempts made to explain the formation 

 and decomposition of all these nitrogenous substances, keeps us 

 within a circle of mere probabilities and possibilities, without 

 affording any solid support for the maintenance of any one view 

 in preference to another. The only fact which we deduce from a 

 simple comparison of the empirical composition of these sub- 

 stances, and from corresponding statistical investigations regarding 

 the metamorphosis of matter in the animal body, is, that the 

 different phases under which nitrogenous molecules appear in the 

 animal organism must be essentially dependent upon the inspired 

 oxygen, and that the latter, under the most various circumstances, 

 gives origin to the numerous metamorphoses which the molecules 

 of albumen undergo before their final change into urea and similar 

 substances. 



In a second group of substances which we have learnt to 

 recognise as important agents in the metamorphosis of animal 

 matter, we must place the fats. We considered their physio- 

 logical importance, origin, and final destruction so fully in the first 

 part of this work, that very little remains to be said on the subject. 

 We learnt (vol. i., pp. 259-272) that the fats, besides the manifold 

 mechanical services which they render the animal organism, also 

 take part, through their chemical metamorphoses, in the most 

 varied animal processes, that they take an active share in the process 

 of digestion in the primes vise, and that they preside generally over 

 all the processes by which the fluid nutrient substances are con- 

 verted into the solid substrata of the organs. The formation of 

 the colourless blood-corpuscles seems also to owe its first impulse 

 to the metamorphosis of fat, which thus serves as the most im- 

 portant auxiliary in the formation of blood. We also, in the same 

 place, drew special attention to the fact, that no animal cell 

 and no fibre was formed independently of the presence of fat. 

 Indeed, the fat appears to possess the property of predisposing 

 the animal organism to the formation of cells. Thus, for instance, 

 whenever very large quantities of fat are introduced into the 

 organism, as in the fattening of live stock, the connective and 

 subcutaneous tissue of different parts exhibit an extraordinary 

 number of cells, all which contain fat. A cell-formation of this 

 kind requires, however, the concurrence of albuminous substances, 



P2 



