120 PRINCIPLES OF STOCK-BREEDING. 



genized elements of the tissue, we have, under these 

 circumstances, a deposition of fatty matter. The fat 

 is here inert, and takes the place of the substance that 

 gives to the part its characteristic function. These 

 phenomena are strikingly apparent in muscles that 

 have been long disused or paralyzed, or in nerves that 

 have lost their functional activity. If the change be 

 not too extensive the fat may be made to disappear, 

 and the part will return to its normal constitution by 

 appropriate exercise ; but frequently the alteration 

 has proceeded so far as to be irremediable and per- 

 manent." * 



The reproductive organs of very fat animals are 

 frequently affected with fatty degeneration, to an ex- 

 tent that impairs or entirely destroys their functional 

 activity. 



In a valuable paper on " The Reproductive Pow- 

 ers of Animals," Prof. Tanner says : " For the pur- 

 pose of more fully investigating the causes of barren- 

 ness, I have examined the ovaries of several heifers 

 which were, after a very careful trial, condemned and 

 killed as barreners, and I have every reason to believe 

 that by far the larger proportion were naturally quite 

 competent for breeding, and that, in the majority of 

 cases, non-impregnation arose from the seminal fluid 

 never reaching the ovum, which was ready for fertili- 

 zation, or from that fluid not being of a healthy char- 

 acter. 



" In some cases in which the ova were, to all ap- 

 pearances, perfectly healthy, the tubes whereby the 

 seminal fluid should have been conveyed were so 



1 Flint's "Physiology of Man " " Nutrition," p. 381. 



