to the Rearing and Feeding of Cattle. 
237 
tried upon a jjoose, which was crammed with maize, and allowed 
to eat salt. The salt taken by the goose was less than that neces- 
sary to produce a purgative action, and yet the goose did not 
fatten. This arose from the excess of food being formed into bile, 
and not into fat. As much bile was consumed as corresponded to 
the oxygen inspired, whilst the remainder passed out with the ex- 
crements, and was detected therein. 
On this account it is a bad practice to give fatting sheep as 
much salt as they will take in summer. Sheep, if I am rightly 
informed, are very fond of salt in summer, but do not take so 
nmch in winter. The reason of this is, that these animals eat 
more food in hot weather than the oxygen respired suffices to 
consume — they, therefore, find it agreeable to carry off this excess 
of food ; this is done by salt, in the manner now described. 
A small quantity tends to their general health, and to the ac- 
tivity of their digestive apparatus; but a large quantity, though 
also favourable to the health of the animal, is detrimental to the 
farmer by preventing a proper return of the food which he sup- 
plies. In winter, sheep do not find salt so agreeable, because the 
greater condensation of the air occasions a more rapid transforma- 
tion of the food. We will again advert to the use of salt when 
treating of the dairy. 
XX. — Second Lecture on the Rearing and Feeding of Cattle. 
By Lyon Playfair. Delivered to the Society, December, 
1842. 
I. The ordinary state of health of an adult animal consists in 
keeping the supply equal to the waste of the tissues of the body. 
When the supply is either greater or less than the waste, it is 
certain that the nutrition of the animal is effected under unnatural 
conditions. 
But the process of nutrition is different in a young animal. 
In youth the supply must be greater than the waste of the body, 
otherwise an increase in the mass of the body could not be pro- 
duced. The life of an adult consists in the sustenance of the 
tissues already fully formed ; while the life of a child includes the 
increase and development of the tissues. The principle which 
produces this increase has been termed the "vegetative life" of the 
animal. It merely consists in an increased ascendancy of vitality 
and subjugation of causes of waste or the chemical forces. 
The respiratory apparatus of a young animal is more active 
than in an adult, and consequently a greater amount of oxygen 
enters its system ; a fact which is attested by the temperature of 
its body being higher than that of its parent. As this oxygen 
