to the Rearing and Feeding of Cattle. 
223 
for every breeder of cattle must be aware, in the wlnterino; of 
younc: stock, that they thrive better, witli less consumption of food, 
when kept well sheltered from cold and wet. 
The assimilative power of the graminivora is enormous, and the 
quantity of food which they consume is proportional. In summer, 
when the temperature of the air approaches more nearly to that 
of the body, the heat generated by the combustion of this food is 
more than is sufficient to retain the normal temperature of the 
system. Hence it is that we find oxen so much inconvenienced 
by hot weather^ and that we observe them standing in streams of 
running water, or exposing themselves, with evident satisfaction, 
to a shower of rain. The cold water serves to carry off the re- 
dundant heat and, consequently, matter, from the body ; for heat 
is produced by the combustion of matter. This practice there- 
fore, although agreeable to the cattle, can scarcely be a profitable 
one for the grazier. 
The air in summer being so much expanded by heat, much 
less air is taken into the system in an equal number of respira- 
tions than in winter — consequently less oxygen is consumed. 
But oxygen is the principal acting chemical force ; it is, there- 
fore, the cause of waste. The case of cattle now feeding is the 
very reverse of what it is in winter. In cold weather, the vital 
force (cause of su])ply) is reduced in energy, whilst that of the 
chemical force is augmented ; but in summer, the vital functions 
are elevated and the chemical powers depressed. Vitality, having 
now a diminished force in antagonism to its action, exerts all its 
powers in increasing the mass of the organs in which it resides ; 
it therefore converts into blood all azotised parts of the food taken 
by the animal, except those which supply the small amount of 
waste. All the excess of blood is converted into flesh (i.e. mus- 
cular tissue and cellular tissue). The animal now becomes fleshy 
and plump. 
The other constituents of the food, such as starch, sugar, and gum, 
are converted into fat, and deposited as adipose tissue. The cause 
of the deposition of fat is this — that sufficient oxygen does not enter 
the system to consume the food, or to convert it into carbonic 
acid and water ; it is, therefore, only partially consumed, or, 
in other words, converted into fat (Liebig).* Fat is not a part 
of the organism ; it is a chemical compound, arising from an un- 
natural state. The fattening of cattle is similar to the growing of 
* This process may be familiarly compared to the manufacture of coal- 
gas. If we burn coal in the open air, carbonic acid gas and water are the 
only products of combustion ; but if there be a deficiency of air, such as in 
the retorts for the preparation of gas, then the whole of the coal is not 
converted into gases, part being again obtained as coal tar. The tar 
formed in this case represents the fat of animals. 
