BUREAU OF ANIMAL INDUSTRY. 677 



microbe was ol>taiucd tlie vesicular portion of the lungs was filled with 

 a cellular exudate, partly derived by a desquamation of the alveolar 

 epithelium and partly by an infiltration of cells from the blood. 



Two rabl>its inoculated by rubbing some of the scrapings from the cut surface of 

 the huv^ tissue into a wound laade on the inner surface of the ear remained welL 

 One mouse inoculated as above ciied next day. No bacteria in the organs. Blood 

 cultures remain sterile. A third rabbit was inoculated by placing a bit of lung sub- 

 stance beneath the skin of the thigh and closing the incision with a stitch. The ani- 

 mal remained well. 



No positive results Avere thus obtained from this specimen. The 

 source of the animal, the time of death not being known, it is not at 

 all improbable that this specific microbe may jjerish in the animal 

 body a certain time after death through frost and other agencies. It 

 is not, moreover, to be denied that only certain portions of the lung 

 tissue are, at a given time, the seat of active bacterial growth. These 

 portions may not have been sent to us. 



It seems that this hitherto unrecognized disease in swine is far more 

 prevalent in the Yv^estern States than was at first supposed. It there- 

 fore becomes necessary to inquire more carefully into the distribution 

 of these two maladies and to determine whether they do not fre- 

 quently exist in the same localities. 



The microbe from Iowa outbreaks showed a greater virulence, as a 

 few drops of culture fluid were sufficient to destroy mice and rabbits 

 in less than twenty-four hours. Whether such differences are suffi- 

 cient to account for the varying severity of the disease in different 

 localities remains to be determined by more extended observation. 

 The fact that the subcutaneous inoculation of cultures did not affect 

 two pigs may be due to a want of power to develop in the internal 

 organs. This is virtually the case in the disease, as it appears natu- 

 rally among- swine. Though the lungs may be extensively diseased, 

 the blood, spleen, and other internal organs are practically free from 

 bacteria. The disease seems to be caused by inhaling or aspirating 

 the specific bacteria, which exert their destructive effect in the alveoli 

 and smaller bronchi, and do not in reality enter the blood of the af- 

 fected animal. The final test will rest upon the possibility of pro- 

 ducing the specific lung disease by means of inhalation experiments 

 which are now being carried on. 



RECENT FOREIGN INVESTIGATIONS IN INFECTIOUS SWINE DISEASES. 



The investigations by foreign observers during the past year upon 

 infectious diseases of swine, and more especially their causation, have 

 led to some interesting results, which deserve careful consideration. 

 In the Second Annual Report of this Bureau it was pointed out that 

 the disease known in this country as swine-plague, or more commonly 

 as hog-cholera, was wholly different from the disease known on the 

 Continent as rouget and Eothlauf. Not only are the lesions different, 

 but the micro-organisms producing them wholly unlike in their mi- 

 croscopical and biological features, as well as in their pathogenic effect 

 upon animals. Thus far rouget has not been found in this country. 

 The conclusions reached last year, though doubted by those who 

 seemed to consider all infectious or contagious diseases of swine iden- 

 tical, are unshaken. All efforts at practicing preventive inoculation 

 in hoo:-cholera with virus derived from rouget must not only be 

 looked upon as absurd in the light of present knowledge, but as dan- 



