Physical Condition of Animal 18 
unusual amount of exercise, or any one of many 
other causes, may be sufficient to decrease the secre- 
tion of milk one-half in any one day. The effect 
of such disturbances is usually quickly overcome, but 
their frequent recurrence leads to a permanent diminu- 
tion of the secretion. The nervous’ organization 
of the animal is a most important factor in deter- 
mining the effect of these various disturbing infiu- 
ences. Many of the animals in which the powers’ of 
digestion, nutrition and secretion are most highly de- 
veloped are possessed also of a highly developed and 
sensitive nervous system, and hence are easily affected 
by any disturbing condition. With all such animals 
it is of the utmost importance that every condition 
surrounding the animal should be as regular and 
uniform as possible. - Other animals of equal capacity 
show a remarkably quiet .and phlegmatic nervous 
temperament, and are consequently slightly or not at 
all affected by such disturbing influences. Such an- 
imals are of great value to the milk producer, for 
with the utmost care and regularity there are always 
disturbing influences beyond the control of the 
dairyman. , 
