CONTAGIOUS PLEURO-PNEUMONIA IN CATTLE 419 
Diagnosis. It is extremely difficult to make an accurate diagnosis 
of the disease during its development, because the symptoms which 
are present are few in number and by no means characteristic. The 
slight fever and cough are the only symptoms of diagnostic importance 
in the prodromal stage. In the second or acute stage a positive 
diagnosis can be made only when cases ,of pleuro-pneumonia have 
previously occurred or when several cases occur simultaneously. As 
a rule, a correct diagnosis can be made only by a post-mortem examin- 
ation. It is to be differentiated from: non-infectious inflammation 
of the lungs; tuberculosis; traumatic pneumonia or pneumonia due 
to foreign bodies; broncho or interstitial pneumonia; and pulmonary 
septicemia hemorrhagica. 
Preventive inoculation and eradication. In Europe inoculation was 
practiced as early as the beginning of the last century. 
The advocates of inoculation, especially Hausmann, Wilhelms, 
Haubner, Bouley, Schiitz and others, start from the well known fact 
that one attack of pleuro-pneumonia successfully passed through 
confers immunity for the remainder of the animal’s life. By inocula- 
tion, a local specific, inflammatory process which is analogous to that 
in the lungs, is produced and is followed by subsequent immunity of 
the whole body. Haubner calculated that the mortality from the 
inoculation is from 1 to 2 per cent. and that the tips of the tails are 
lost in from 5 to 10 per cent. of the cases. Since the work of Nocard 
and Roux in 1899, cattle have been immunized in France by the 
inoculation of pure cultures of the virus. Serum for hyperimmunized 
cattle gives, on repeated large doses, additional resistance. 
The opponents of inoculation assert that up to the present no posi- 
tive case of immunity has been proved to have been obtained from 
inoculation. They also point to the fact that even the advocates of 
inoculation are unable to give the exact duration of the immunity and 
consequently make several inoculations. The best procedure seems 
to be the stamping out of the disease by means of slaughter of all 
infected and exposed cattle, thorough disinfection or destruction by 
fire of all infected sheds and barns. The success of this method is 
illustrated by the eradication of the disease from the United States. 
REFERENCES 
1. Boynton. Notes on the muscular changes brought about by intermuscular 
injection of calves with the virus of contagious pleuro-pneumonia. Bull. No. 20, 
Bur. of Agric. P. I., 1912. 
2. Dusarprn-Beaumetz. Le microbe de la péripneumonie et la culture. Thésis, 
Paris, 1900. 
