476 KEPORT OF THE COMMISSIONER OF AGRICULTURE. 



This correspondence is sufficient to sliow, witliout further explana- 

 tion, wliy no part of the appropriation has been used for the purchase 

 and slaughter of infected herds. 



INOCULATION BY STATE AUTnORITEES AND OTHERS. 



Inoculation has been practiced to a considerable extent in Brooklyn, 

 N. Y., by local practitioners, cattle dealers, and the owners of inlectod 

 herds. In Kew York, New Jersey, Pennsylvania, Delaware^ and Mary- 

 Innd, it ha.s been largely practiced by the local authorities. While this 

 )>r()L'oedin<:!^ may have saved the owners of infected herds the loss of a 

 lev/ animals, and has possibly relieved these States from a certain amount 

 of embarrassment as to the disjiosition of infected herds, it must, never- 

 theless, be looked upon with alarm from a national point of view. The 

 inoculated herds arc not subjected to that close supervision which is 

 necessary to prevent the sale of animals, nor is the period of quarantine 

 maintained for a sufficient time for all danger to be passed. Animals 

 which are mildly affected are inoculated with the healthy ones, and 

 within three months after the last case of the disease is known to the 

 authorities all quarantine restrictions are removed. It is absolutely 

 certain from the experience in Europe and this country with inocula- 

 tion, that the infection is maintained in inoculated herds for a much 

 longer time than three months, and that fresh animals introduced into 

 these herds are very liable to contract the disease. This point will be 

 elaborated in the Second 'Annual Eeport of the Bureau of Animal In- 

 dustry, and is referred to hero to draw attention to this source of dan- 

 ger which has been rapidly increasing in importance during the last 

 year. 



INVESTIGATIONS IN SWINE PLAGUE. 



t 



During the past year the investigations concerning this disease were 

 carried on without intermission. The methods adopted were those used 

 by the most advanced investigators, as well as those which suggested 

 themselves to us directly, and grew out of the necessities of the case. 

 At least twenty animals were carefully examined in the earlier part of 

 the year. In nearly all instances the disease had been communicated 

 from the sick to the healthy by contagion, either at the experimental 

 station of the Bureau or in neighboring herds. Very few showed any 

 disease of the lungs 5 in fact the disease manifested itself chiefly by ex- 

 tensive ulcerations of the ccecum and colon (Plate I). The animals lin- 

 gered usually from one to three weeks after the first appearance of the 

 disease, and in nearly every case were kiUed in the last stages to prevent 

 any jpos^ mortem changes, as the animals, when left to themselves, often 

 die early in the night and decomposition sets in very rapidly during 

 the spring and summer months in this climate. 



It was our intention to study carefully the microbes found in the vari- 

 ous exudates of the serous cavities, especially that of the peritoneal 

 cavity, which has been considered very virulent by former observers. 

 In cases of advanced disease, characterized by extensive ulcerations of 

 (lie largo intestine, it was found, on microscopic examination of lymphatic 

 glands and other organs invested by the peritoneum, that the latter 

 membrane was covered with a layer of lymph, in which were imbedded 

 various kinds of bacteria, micrococci of different sizes, slender as well 

 as tliick bacilli. Cover-glasses brought in contact with the peritoneum 



