44 THE LUNG PLAGUE OF CATTLE. 



tains some who would readily succumb to the temptation. But if the 

 temptation is great for the stock-owner, it is even more so for the dealer. 

 His daily study, to buy in the cheapest market and sell in the dearest; 

 places the bait in exact parallelism with his habits of thought, and with 

 him it requires a special effort to shut his eyes to the advantage which 

 confronts him. How much stronger is the temptation when, perchance, 

 even he has been betrayed into buying stock which he discovers to have 

 come from an infected herd, but too late to annul the bargain. Moreover, 

 he is especially exempt from the risk of suspicion of evil design ; none 

 can charge him with knowledge of the antecedents of cattle which he 

 bought at sight, and for which he paid, risking his money, and, to some 

 extent, his reputation. If the fact of his having sold infected animals 

 is finally charged upon him, he too can appear as the innocent victim 

 and charge back on the original owner, perhaps an unknown party, the 

 crime of selling such stock. 



But what would be thought of a civil authority or a professional man 

 who would aid and abet such transactions by granting a certificate of 

 soundness on a simple examination in transit, or an examination of one 

 or more cattle without reference to the herd from which they come? 



We shall refer to this subject again in connection with international 

 and interstate quarantine, and the quarantine of infected and suspected 

 animals, herds, and places, all of which to be effective must meet every 

 contingency implied in the occasionally prolonged incubation as above 

 set forth. 



SYMPTOMS. 



These vary in different countries, latitudes, seasons, altitudes, races of animals and 

 individuals. They are, cwteris paribus, more severe in hot latitudes, countries, and 

 seasons than in the cold; in the higher altitudes they are milder than on the plains; 

 in certain small or dwarfed animals, with a spare habit of body, like Brittanies, they 

 appear to be less violent than in the large, phlegmatic, heavy-milking, or obese short- 

 horn, Ayrshires and Dutch; a newly infected race or cattle in a newly infected country 

 suffer much more severely than those of a land where the plague has prevailed for 

 ages; and finally certain individuals, without any appreciable cause, have the disease 

 in a much more violent form than others which stand by them in precisely the same 

 conditions. 



Sometimes the disease shows itself abruptly with great violence and without any 

 appreciable premonitory symptoms, resembling in this the most acute type of ordinary 

 broncho-pneumonia. This, however, is mostly in connection with some actively ex- 

 citing cause, such as exposure to inclement weather, parturition, overstocking with 

 milk, heat, &c. 



Far more commonly the symptoms come on most insidiously, and for a time are the 

 opposite of alarming. For some days, and quite frequently for a fortnight, a month 

 or more, a slight cough is heard at rare intervals. It may be heard only when the 

 animal first rises, when it leaves the stable, or when it drinks cold water, and hence 

 attracts little or no attention. The cough is usually small, weak, short and husky, 

 but somewhat painful and attended by some arching of the back, an extension of the 

 head upon the neck, and protrusion of the tongue. This may continue for weeks 

 without any noticeable deviation from the natural temperature, pulse or breathing, 

 and without any impairment of appetite, rumination, or coat. The lungs are as reson- 

 ant to percussion as in health, and auscultation detects slight changes only, perhaps 

 an unduly loud blowing sound behind the middle of the shoulder, or more commonly 

 an occasional slight mucous rattle, or a transient wheeze. In some cases the disease 

 never advances further, and its true nature is to be recognized only by the facts that 

 it shows itself in an infected herd or on infected premises, and that the victim proves 

 dangerously infecting to healthy animals in uuinfected localities. It may be likened 

 to those mild cases of scarlatina which are represented by sore throat only, or to the 

 modified small-pox, known as varioloid. 



In the majority of cases, however, the disease advances a step further. The animal 

 becomes somewhat dull, more sluggish than natural, does not keep constantly with 

 the herd, but may be found lying alone; eats and ruminates more tardily and less fre- 

 quently; breathes more quickly ('20 to 30 times per minute in place of 10 to 15); re- 

 tracts the margins of the nostrils more than formerly; the hair, especially along the 

 neck, shoulders and back, stands erect and dry; the muzzle has intervals of dryness, 



