NUTRITION AND GENESIS. 461 



carbonaceous molecules locally produced by decomposition of 

 the nitrogenous molecules, have not been replaced by other 

 nitrogenous molecules, as they should have been. This fatty 

 degeneration is, indeed, a kind of local death. For so regard- 

 ing it we have not simply the reason that an active substance 

 has its place occupied by an inert substance ; but we Ixave 

 the reason that the flesh of dead bodies, under certain 

 conditions, is transformed into a fatty matter called adipocere. 

 The infertility that accompanies fatness in domestic animals, 

 has, however, other causes than that declining constitutional 

 vigour which the fatness indicates. Being artificially fed, these 

 animals cannot always obtain what their systems need. That 

 which is given to them is often given expressly because of its 

 fattening quality. And since the capacity of the digestive 

 apparatus remains the same, the absorption of fat-producing 

 materials in excess, implies defect in the absorption of ma- 

 terials from which the tissues are formed, and out of which 

 young ones are built up. Moreover, this special 



feeding with a view to rapid and early fattening, continued 

 as it is through generations, and accompanied as it is by 

 a selection of individuals and varieties which fatten most 

 readily, tends to establish a modified constitution, more fitted 

 for producing fat and correspondingly-less fitted for producing 

 flesh a constitution which, from this relatively -deficient ab- 

 sorption of nitrogenous matters, is likely to become infertile ; 

 as, indeed, these varieties generally become. Hence, 



no conclusions respecting the effects of high nutrition, pro- 

 perly so called, can be d/awn from cases of this kind. The 

 cases are, in truth, of a kind that could not exist but for 

 human agency. Under natural conditions no animal would 

 diet itself in the way required to produce such results. And 

 if it did, its race would quickly disappear.* 



* It is worth while inquiring whether unfituess of the food given to them, ic 

 not the chief cause of that sterility which, as Mr. Darwin says, " is the great 

 bar to the domestication of animals." He remarks that "when animals and 

 plants are removed from their natural conditions, they are extremelv liable to 



