CONTAGIOUS DISEASES OF DOMESTICATED ANIMALS. 379 



Morbid changes found at thcijost-mortem examination. — Distiuctly limited 

 (circumscribed) liepatizatiou at several places iu both lobes of the lungs, 

 e;.ich feiugie patch comprising only a lew lobules, but very distinct aixl 

 well defined. (See ijhotogi-aph of Plate 1, of a portion of the anterior 

 part of the left lobe, which shows two small hepatized patches.) Tlie 

 most extensive hepatization was foimd along a larger bronchus in the 

 posterior part of the left lobe. The hepatized i)arts or patches amounte<l 

 to about 4 or 5 per cent, of the whole pulmonal tissue. The mucous mem- 

 brane of the bronchie was found to be slightly swelled ; a small quantity 

 of serum was found in the pericardium and in the chest, and a little more, 

 a few ounces, in the abdominal cavity. The lymphatic glands situated 

 in the chest, and those belonging to the meseuterium, were enlarged, 

 some of them, esj)ecialiy the latter, to a considerable extent. All other 

 organs appeared to be perfectly healthly and normal. The blood prob- 

 ably was a shade darker than that of perfectly healthy cattle butchered 

 or kiUed by bleeding. 



The experiment with heifer No. 2 has proved beyond a doubt that 

 swine plague can be communicated to cattle by dii'ect inoculation, though 

 perhaps only in a mild form ; 2, that cattle possess less susceptibility 

 than swine, and are not easily infected; and 3, that the principal morbid 

 changes of swine plague, communicated to cattle by inoculation, present 

 themselves as hepatization of the i^ulmonal tissue, and are essentially 

 the same in cattle as in swine. 



Since the i)ossibility of a communication of swine plague from hogs 

 to cattle has tlius been proved, and since it has been ascertained by 

 other experiments that sna ine plague is communicated from hog to hog, 

 not only through wounds and scratches (direct inoculation), but also 

 with equal facility by an introduction of the infectious principle with 

 the food, or with the water for drinking, into the digestive canal, there 

 remains in my opinion, not the least doubt that the heifer killed in Feb- 

 ruary in tlie Union stock-yard, which was raised in a hog-lot among dis- 

 eased hogs, and compelled not only to eat and drink with diseased hogs, 

 but probably also to consume food and water soiled and contaminated 

 with the exceedingly infectious excretions of diseased hogs, was diseased 

 with communiciited swine plague, aggravated, maybe, by rough treat- 

 ment and transportation by rail. ISfay, more, it was even i^ossible that 

 the cattle (steers) condemned last winter in England as affected with 

 pleiiro-pneumonia, and alleged to be American, and even Western cattle, 

 have either not come froin the West, or from any of the Western States, 

 in which contagious pleuro-pneumunia has ever been known to exist, 

 or have not been diseased with contagious bovine pleuro-pneumouia, 

 but only with communicated swine plague. On a great many farms iu 

 nearly all tlie Western States, the steers and hogs to bo fattened for the 

 market are frequently fed in one and the same feed-lot, and eat the same 

 food and drink of the same water. It is therefore possible that swine 

 plague, since it prevails almost eveiy where in the whole stock-producing 

 West, has been communicated in a few instances to steers; that those 

 steers aiiected with only a very mild attack, too mild to be noticed, 

 passed througli the stock-yards in tiie West and at the sea-coast as unsus- 

 pected and healthy animals, and that the originally mild form of com- 

 municated swine plague becamo sufficiently aggTavated by transiK)rta- 

 tion, exposure, hardship, and coniinement on the Atlantic steamer, to 

 be readily mistaken lor bovine lung-plague or contagious pleuro-pneu- 

 mouia by the time the cattle ariived in England. 



