86 
Hereditary Diseases of Cattle. 
especially where these are most numerous and most vascular. 
Here irritation and inflammation of a morbi<l character are ex- 
cited ; and the products of the disease being endowed with great 
powers of self-reproduction, the tumour rapidly extends, and no 
power is adequate thoroughly to remove it. 
The congestive and puerperal fevers of cattle are not usually 
considered hereditary. Tliey may justly, however, be viewed as 
typical of those diseases forming the link between hereditary 
and non-hereditary affections. Indeed, their most common and 
powerful predisposing cause is a plethoric habit of body, which 
is undoubtedly liereditary. Congestive or inflammatory fever 
attacks young cattle, thriving rapidly, and in which a large amount 
of highly nutritive blood is being manufactured. If, from any 
cause, the balance of the circulation be disturbed in animals in 
this plethoric state, the serum and red globules of the blood 
become effused into the cellular tissue, especially of the loins and 
extremities, causing the extensive crackling enlargements, con- 
taining gas and bloody serum, which are so characteristic of the 
disease. Tliat variety of puerperal fever, affecting the brain and 
other nervous centres, may also be considered, to a certain extent, 
hereditary, since it only affects animals in a plethoric state. This 
state may sometimes be produced artificially, but is more com- 
monly natural, especially in many of the more improved breeds 
of cattle. Cows in high condition, that have previously produced 
large C|uantities of milk, are especially subject to puerperal fever. 
During gestation a large amount of blood is appropriated to the 
nutriment of the fojtus ; but this drain on the system of the 
mother ceases at parturition, and, if at this time anything occur 
to arrest the secretion of milk, a large volume of blood soon ac- 
cumulates in the system, especially of animals of a plethoric 
constitution ; effusion speedily ensues, causing pressure on the 
brain and nervous centres, and producing all the well-known 
symptoms of puerperal fever. 
We have noticed most of the diseases of cattle which assume 
a hereditary type ; and it will not, we think, be out of place now 
briefly to indicate those characters which it is desirable that 
cattle should possess, in order that they may perpetuate in their 
offspring a healthy and vigorous constitution, and an adaptation 
for fattening and for dairy purposes. The head should be small 
in proportion to the size of the animal, the muzzle fine and taper- 
ing, the nostrils large and open, and the eyes full and lustrous — 
the two latter characters being Indicative of strength and vigour 
of constitution. The horns, when present, should be fine, smootli, 
and well turned, the ears small and not too thick, the head, as 
breeders say, " well set on " the neck. The distance between 
the ears and the angle of the jaw should be short, but the width 
