io 4 PHYSIOLOGICAL 



is considerably bigger than in the Carnivora, though smaller 

 than in the horse. The enormously distended rumen or paunch 

 and the other alimentary compartments at the fore-end of the 

 gut, compensate in ruminants for the somewhat reduced large 

 intestine. Thus it may be said that the rumen in the ox is the 

 functional though not the anatomical equivalent of the caecum 

 and colon in the horse or rabbit. 



An examination of the faecal or undigested residue evacuated 

 through the anus tells the same story. Bischoff and Voit 1 pointed 

 out long ago that the faeces of the Carnivora when fed on lean 

 meat consist almost entirely of excretory products which are 

 got rid of through the wall of the gut, and are strictly comparable 

 to the organic matter of the urine. Only traces of undigested 

 food occur. " Metabolic products " consisting of altered residues 

 of digestive fluids, mucus, etc., are evacuated in small quantities 

 even in a condition of abstinence when the gut is empty of food 

 the so-called "fasting faeces," and according to Armsby 2 "the 

 consumption of highly digestible food e.g. lean meat does 

 not seem materially to increase " even the fasting faeces, "though 

 when food containing indigestible matter is eaten it is believed 

 they increase in quantity." Moreover, unless the meat is given 

 too freely the faeces of the dog never contain undigested muscle 

 fibres. Dogs when fed on a diet of meat defaecate (i.e. empty 

 their bowels) at intervals of from two to four days, and as already 

 remarked the amount of residue ejected is extremely small, per- 

 haps 3 or 4 oz. Meade Smith 3 has calculated that a dog weigh- 

 ing 35 kilogrammes and fed on a half to two and a half kilos of 

 meat, evacuates from 27 to 40 grammes of faeces containing 

 only 9 to 21 grammes of solids. "Therefore, it may be said 

 that with a flesh diet, only one per cent, of the amount of solids 

 taken with the food escapes from the body in the form of faeces." 

 On the other hand in herbivorous animals defaecation takes 

 place at very frequent intervals, and large quantities are passed 

 per anum. Thus the horse evacuates every three or four hours, 



1 Bischoff and Voit, Die Gesetze der Ernahriwig des Fleisch Gressers, 1860. 



2 Armsby, Principles of Animal Nutrition, New York, 1906. 



3 Meade Smith, The Physiology of the Domestic Animals, Philadelphia, 

 1889. 



