334 Manual of Veterinary 3Iicrobiotogy. 



Distemper of young dogs. 



The contaoiousness of this disease is well estab- 

 lished although our knowledge of the germs which 



by Bab^s is the disease of cattle known in America as "Texas 

 fever." It occurs in an acute and in a mild form, the latter be- 

 ing in a sense endemic in the southern United States, whilst the 

 acute form prevails in northern cattle which have been imported 

 to these regions or which have been exposed to the infection 

 brought north by cattle from the infected districts. The chronic 

 or mild type, as it occurs in southern cattle, generally passes uu- 

 perceived. Mild forms of the disease are also frequent among 

 northern cattle, especially when they receive the infection during 

 the cooler weather of autumn. The acute disease (which occurs in 

 the northern States only during the hot weather of summer) is 

 generally fatal; in non-fatal cases it is sometimes followed by a 

 prolonged period of unthrift and debility. Calves are less sus- 

 ceptible than adult animals and after one or more attacks acquire 

 a certain degree of immunity; to this cause is attributed the com- 

 parative immunity possessed by cattle native to the southern 

 States. It appears, however, that this immunity is not perma- 

 nent and may be lost when such cattle are kept for several sum- 

 mers in non-infected regions. The most noticeable symptoms of 

 the acute disease are those of an intense continuous fever with 

 the passage, in most cases, of red or dark-red colored urine ; un- 

 steady gait and muscular tremors in the neck and limbs occur 

 toward the last stage ; occasionally symptoms of delirium are ob- 

 served. 



Pathological anatomy. — The most important lesions observed at 

 the autopsy are : Injection of the vessels and occasionally patches 

 of extravasation in the subcutaneous connective tissue ; blood 

 thin and watery (Smith), or frequently of normal appearance; 

 lungs normal or discolored by congestive patches; heart muscle 

 congested, points of extravasation on the pericardium and endo- 

 cardium ; spleen enlarged, its capsule streaked and mottled by 

 the injected vessels, pulp dark red and diffluent ; liver generally 

 much enlarged and darkened from blood congestion or light yel- 

 low in color from extreme engorgement with bile ; gall blad- 

 der full of thick, dark, grumous bile ; kidneys generally congested. 



