NUTRITION 363 



to the purposes of digestion. Further, the blood must be kept 

 fluid and concentration avoided ; a concentrated blood draws 

 on the tissues for fluid, but later on, this source dries up, and 

 unless dilution of the blood be effected, death is only a matter 

 of time, and with horses undergoing severe exertion a very short 

 time before complete collapse occurs. 



Starvation. — When an animal is starved it lives on its own 

 tissues ; in the herbivora the urine becomes acid, hippuric is 

 replaced by uric acid, and the secretion becomes transparent. 

 We have seen (p. 351) that the elimination of nitrogen by the 

 starving animal at first falls rapidly, then gradually. During 

 starvation the carbon dioxide excreted falls in amount, and the 

 oxygen absorbed becomes reduced, though not in proportion to 

 the fall of carbon dioxide. If water be given, life is considerably 

 prolonged ; Colin records a case where a horse receiving water 

 lived thirty days without food. It is notorious that herbivora, 

 though they lose less protein during starvation than carnivora, 

 do not withstand starvation so well ; nor need we go so far as a 

 starvation experiment to ascertain this fact. When men and 

 horses are being hard worked, the loss in condition amongst the 

 horses sets in early, and is extremely marked for some time before 

 the men show any appreciable muscular waste. 



Horses have been known to live without food or water for as 

 long as three and dogs for four weeks ; but it is said that if horses 

 have suffered fifteen days' starvation, the administration of food 

 after this time will not save them.* Colin records an experiment 

 where a horse weighing 892 pounds died after thirty days' star- 

 vation, only being allowed 2 J pints of water per diem. The 

 animal was nourished on its own tissues, the daily loss in weight 

 being 5-9 pounds, which must be considered as exceptionally 

 small. Dewarj records two remarkable instances of the length 

 of time sheep will withstand starvation ; in one instance eighteen 

 sheep were buried in the snow for six weeks and only one died. 

 In the second case seven sheep were buried for eight weeks and 

 five days, and all were recovered alive, and eventually did well. 



In some very accurate experiments on a starving cat, it was 

 shown that the principal loss occurred in the fat, 97 per cent, of 

 which disappeared in thirteen days. The following table shows 

 the percentage of dry solid matter lost by the tissues : 



Fat ------ 97- o per cent. 



Spleen - - - - - - 63-1 „ 



Liver ------ 566 ,, 



Muscles 30-2 „ 



Blood - - - - - - 17*6 „ 



* If the writer's memory serves him, this period also applied to man 

 during the Great Famine in India several years ago. 

 f Veterinarian, May, 1895. 



