279 
Extracts from British and Foreign Journals. 
ON THE HEREDITARY DISEASES OE HORSES AND CATTLE. 
By W. F. Karkeek, M.B.C.V.S., Truro. 
( Continued from p. 162.) 
The foregoing examples are mostly diseases of structure; 
we will now consider others where the blood may be con- 
sidered as taking a part in hereditary transmission. 
II. [a.) Tubercular Phthisis, or consumption in cattle, will 
afford an interesting case of this sort; and although pre- 
sumably a structural disease, yet it is one that is evidently 
produced from a vitiated state of the blood, arising either 
from defective food, or from living in a contaminated atmo- 
sphere. From either of these causes, the blood is rendered 
unfit for adequate nutrition, and the lungs become diseased 
from the deposition of tubercles on its surface in conse- 
quence. These deposits are much more commonly produced 
in cattle than is generally imagined. During the early 
periods of life the vital principle of stock of this description 
is but too frequently taxed by resistance required to be made 
against cold, wet, and insufficient food, causing mal-nutrition. 
The organic materials of the body are not persistent, but are 
more or less prone to decay, becoming effete or worn out in 
a limited period of time. But, in the healthy body, there is 
a reparatory process continually countervailing this decay, by 
the deposition of new materials whose vital affinities are 
energetic, and able to maintain the integrity of the textures. 
This renewal depends on the supply of healthy chyle to the 
living structures, and, if it be defective in quantity or quality, 
mal-nutrition takes place, and the fibrin of the blood, instead 
of acting as a plastic material for renewing the worn-out 
parts, becomes a source of tubercles, and the lungs speedily 
suffer, and that oftentimes to a considerable extent. 
Breeders of cattle may rest assured that the offspring of a 
consumptive cow is almost certain to inherit a disposition to 
the disease, and, when this is the case, it is quickly induced 
by any cause that may reduce the healthy vigour of the sys- 
tem, such as exposure to cold and wet, causing congestions 
and chronic inflammations — or, as previously stated, from 
being insufficiently fed. 
It is a question, too, well worth considering, whether this 
