250 The Applications of Physiology 
prevents their wandering about : thus they obtain exercise suffi- 
cient to furnish them with a good appetite, and the butter in the 
milk is not consumed. On the other hand, if the night proved 
cold, more injury than good would be experienced by this system, 
for a greater amount of butter would be destroyed. Stall-fed 
cows furnish the greatest proportion of butter, a fact to which we 
shall again advert. Any deficiency of heat must occasion a com- 
bustion of butter to supply the requisite quantity. On this 
account we select warm sheltered pastures for our cows, and do 
not expose them to sudden changes of temperature. When butter 
is the object desired by the dairyman, too rich pasture cannot be 
supplied to his cows. 
The production of cheese in the milk involves certain other 
conditions. I have travelled through the principal cheese dis- 
tricts to acquire information on this point, but the evidence fur- 
nished by cheese-dairymen is very conflicting, and apparently 
contradictory. Almost all cheese districts agree in asserting that 
poor land is best adapted for cheese, though there are certain 
other districts in which the very reverse is affirmed. This arises 
from the quality of cheese manufactured : those dairies which de- 
pend equally upon their butter and cheese, and prepare the latter 
principally jfrom skimmed milk, must possess rich pastures fitted 
principally for butter ; but in dairies such as those of Somerset- 
shire or Cheshire, in which butter is of a secondary consideration, 
their pastures are in reality not so rich. In Gloucestershire and 
Somersetshire I found the opinion prevalent that poor land pro- 
duced the best (greatest amount of ?) cheese ; and in the third 
volume of ' Young's Six Months' Tour' it is stated, 'in Cheshire 
they find that the inferior sorts of pasture lands are the best suited 
for cheese.' 
In poor lands the cows have more ground to traverse in order 
to obtain a sufficiency of food, and consequently the oxygen re- 
spired by the increased exercise compels them to eat a greater 
quantity. By this increased quantity more cheese (casein) is fur- 
nished to the milk. Land is considered rich, not when its grass 
abounds in albumen, but when it contains the constituents of food 
fitted for the production of fat. And, if my opinion formerly ex- 
pressed be correct, viz., that the waste of the tissues increases in- 
directly the amount of casein in the milk, then another reason is 
given why poor land should be better adapted for the growth of 
cheese than that which is rich. 
Rich grass (/. e. grass which contains a large proportion of 
carbon) is more fitted to sustain the animal heat of the body than 
grass of a poorer nature — consequently less of it is necessary for 
this purpose, or, in the language of agriculturists, its equivalent 
is higher. The equivalent of poor grass being lower, a greater 
