676 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



Since fat and muscle have disappeared in largest amount, it is evi- 

 dent the starving animal feeds on its own flesh, and, under such circum- 

 stances, the urine of the herbivora and carnivora are identical. 



Of the different organs the percentage of loss of original weight is 

 as follows : — 



Bones 



13.4 per cent. 



or 5.4 i 



Muscles, 



30.5 " 



" 42.2 



Liver, . 



53 7 " 



" 4.8 



Kidneys, 



25.9 " 



" 0.6 



Spleen, 



66.7 " 



" 0.6 



Pancreas, . 



17.0 " 



" 0.1 



Testicle, 



40.0 " 



" 0.1 



Lungs, 



17.7 " 



" 0.3 



Heart, 



2.6 " 



" 0.02 



Intestine, . 



18.0 " 



" 2.0 



Brain and Cord, . 



3.2 " 



" 0.1 



Skin, . 



20.6 " 



" 8.8 



Fat, . 



97.0 " 



" 26.2 



Blood, 



27.0 " 



" 3.7 



Other organs, 



36.8 " 



" 5.0 



Since in fasting all the nitrogen leaves the body in the form of 

 urea, the amount of urea in the urine gives a means of measuring the 

 waste of the albuminoid constituents of the body. Even up to the time 

 of death the body continues to eliminate urea without, of course, any 

 new albuminoid matter entering the economy, thus showing that there is 

 a gradual and constant waste of proteids in the bod}'. The amount of 

 urea eliminated progressively decreases, as, of course, there is no repair 

 of the stock of proteids from which it is drawn. Thus, a dog, which 

 during feeding eliminates daily 63.96 grammes of urea, during the first 

 day of starvation removes only 14.91 grammes, and there is then a 

 gradual diminution in the amount up to the time of death. Thus, on the 

 fifty-ninth day of starvation the dog alluded to above only eliminated 

 3.50 grammes of urea. 



Of course, the richer the tissues are in proteids, the greater will be 

 the difference between the amount of urea eliminated in the first and sub- 

 sequent days of starvation. If before the commencement of the starva- 

 tion experiment the animal has been on a spare diet, less urea will he 

 eliminated in the first days of fasting, and then the decrease in amount 

 will be more gradual than if it had been well fed. 



The destruction of albumen in starvation is, however, by no means 

 parallel to the amount of proteids in the entire body ; or, in other words, 

 an animal which on the first day of starvation destroys five times as 

 much albumen as on the tenth does not have on the first day five times 

 as much proteid in the body as on the tenth. 



Voit has found that the excretion of urea on the first day after full 

 feeding is so much greater than under other circumstances that he con- 

 cluded that the amount of proteids in the body is of less importance 



