42 THE LUNG PLAGUE OF CATTLE. 



Mrs. Murphy, Brooklyn, in 1878, bought a cow of McCabe, a New 

 York dealer, which infected her whole herd, so that she had to slaughter 

 the whole. 



In 1878 Mrs. Kelly, Hazelton, Jamaica, Long Island, bought a cow of 

 Braun, a Brooklyn dealer, which sickened and died and fatally infected 

 her three remaining cows so that all perished. 



In February, 1879, Mr. Carr, One hundred and forty-sixth street, New 

 York, had a cow sent on trial by Geissmann, a dealer. She stood but 

 one night in his stables, being removed next day because she looked 

 bad, and another was sent in her place. Carr's whole herd of five con- 

 tracted the disease severely, and were slaughtered accordingly. 



Patrick McCabe, Seventy-second street, New York, bought a cow of 

 McDonald, a dealer, in 1871. Six weeks later she sickened and infected 

 his five remaining cows, all of which perished. He placed four fresh 

 cows in the stable, and started anew, but lost the whole in the course 

 of two months. 



This is but a repetition of the South African experience. During the 

 cold and dry winter in New York the disease is comparatively mild, and 

 the percentage of losses low; but with the return of hot weather all 

 this is changed; the disease often kills after two or three days of ob- 

 served illness, and the percentage of deaths will rise to seventy, eighty, 

 ninety, or even one hundred. This is full of solemn significance to the 

 United States; let the plague once reach the Southern States, and this 

 high mortality would be maintained throughout the greater part of the 

 year; let it reach the Mississippi Valley, and the excessive heats of the 

 summers would make it no less destructive during that season; so that 

 in estimating the probable losses in case of such extension we can no 

 longer accept the losses of Europe as a guide, but must seek for a par- 

 allel under the burning sun of Africa. If we continue to neglect the 

 affection until it shall have spread to these places, we shall subject our- 

 selves to the severest condemnation in thus neglecting to avert a great 

 and lasting public calamity. 



PERIOD OF INCUBATION. LATENCY. 



The time that elapses between the receiving of the germs into the system and the 

 manifestation of the earliest symptoms of the disease, varies greatly. Delafond sets 

 it at from six to sixty days, Verheyen from ten to sixty days, the French Commission 

 extends the period to sixty-seven days, Reynal has seen it exceed ninety days, and 

 Roll and Gamgee quote from eight days to one hundred and twelve. It is true that 

 Garngee qualifies this by the statement that when an animal sickens four months after 

 purchase, two or three latent instances of the diseases have preceded the obvious one. 

 Australia, South Africa, and Norway were each infected by cattle that had shown a 

 period of incubation of three mouths. I have frequently seen cases in which cattle 

 have passed three or four months after the purchase in poor health, yet without cough 

 or any other obvious diagnostic symptoms, and at the end of that time have shown 

 all the symptoms of the lung plague. -But as such cows are considered by the ordinary 

 observer to be well, and as many of them will convey to the mind of the veterinarian 

 nothing more than unthriftiness, we must, as a working rule, accept as possible an 

 incubation of three or even four mouths. All quarantine regulations for this disease 

 must be based on this occasionally long period of latency. 



As regards the real or regular period, we may deduce something from the exudation 

 and swelling in the tail in inoculated cases. The average period is on the ninth 

 day, though it may appear as early as the fifth, or it may be delayed till the thirtieth 

 or fortieth day. In the experimental transmission of the disease by cohabitation, 

 under the French Commission, a cough the earliest symptom appeared from the 

 sixth to the thirty-second day, and sometimes continued^ for months, though no acute 

 disease supervened. (The Lung Plague. Law.) 



It may be stated in this connection that in the recent experiments of 

 Professors Bruylants and Verriest on the artificial cultivation of the mi- 

 crococcus of lung plague in albuminous solutions, thirty hours were found 



