360 A MANUAL OF VETERINARY PHYSIOLOGY 



saving in time effected. The obesity aimed at with ' show ' 

 cattle, sheep, and pigs is a pathological condition repugnant to 

 common sense, and the outcome of a barbarous fashion. The 

 laws regulating the fattening of animals are mentioned at p. 368. 



The consensus of opinion is in favour of castration as facilitating 

 fattening, though this view has not stood the test of scientific 

 inquiry. It is conceivable that if it has some such effect, it may 

 easily be explained on the ground of greater freedom from excite- 

 ment. It is quite certain that geldings have no greater disposition 

 to accumulate fat than mares, and if castration favoured fatten- 

 ing there would be no need for that constant striving after fatness 

 instead of ' fitness,' which is so characteristic of all who have 

 charge of horses. There are, of course, some animals which have 

 a tendency to store up fat and others which never do any credit 

 to their ' keep,' but this is an individual peculiarity not explained 

 by castration. 



The fat of horses is soft and of sheep hard ; that of cattle 

 occupies a middle position. Each animal has fat of a certain 

 melting-point to store up, and whether this be derived from oil, 

 carbohydrate, or food-fat, makes very little, if any, difference. 

 In the fattening of the herbivora it is considered that carbo- 

 hydrates are better fat producers than food fat. The form in 

 which the fats in food are stored up has been made the subject 

 of many experiments : a dog fed on a hard fat converts it into 

 canine fat, which is soft ; cattle fed on fluid fats, such as linseed oil, 

 convert them into hard body fats ; still, experiments go to show 

 that foreign fats used for feeding may, if given in sufficient 

 amount, be recognised in the tissues. Oil-cake and linseed oil 

 may produce an oily milk, owing to the increased amount of 

 olein, and dogs constantly fed on mutton-fat may accumulate 

 this type of fat in the body. Pigs receiving too large a pro- 

 portion of oil in the diet accumulate a soft fat, which boils away 

 in cooking ; and swedes will produce the same result. It is said 

 that green food, hay, and carbohydrates, produce a hard body 

 fat, while grain feeding, such as oats, conduces to a soft fat. 



Fats, like carbohydrates, exert a sparing action on proteins, 

 and for this reason a fat animal takes longer to starve to death 

 than one which is less fat. 



Inorganic Food. — The salts in the body perform important 

 functions in connection with secretion and excretion ; as Foster 

 expresses it, they direct the metabolism of the body, though 

 how they do so is unknown. To their presence is due the normal 

 composition of the body fluids and tissues, for they regulate the 

 water-flow from blood to tissues and vice versa. Proteins which 

 are freed from salts are quite altered in their essential characters, 

 while the part taken by the salts of the body in blood-clotting, 

 rhythmical contraction of the heart, irritability of muscle and 



