162 KEPOET OF THE BUREAU OF ANIMAL INDUSTRY. 



surface irregular, colored yellow, brown, or green. Hemorrhage, due to the ulcer- 

 ation, was observed in one case. 



In many animals the lungs were healthy. In some a muco-purulent catarrh of 

 the bronchi was present, which caused atelectasis in one or more places with young 

 and weak animals. Usually the ventral and anterior lobes were affected. In the 

 diseased lobes homogeneous, cheesy masses appeared later, sometimes as large as a 

 walnut. These masses led subsequently to inflammation and adhesion of the pleura 

 to chest wall, pericardium, etc. The spleen was not changed as a rule. In a few 

 cases only it was somewhat enlarged, soft, dark red. 



When we compare these lesions with those found in our country 

 we observe the absence of hemorrhagic lesions and enlargement of 

 the spleen and the presence of more marked exudative and diphther- 

 itic changes in the large intestine. In numerous sections of ulcerative 

 changes we have not observed any relation between these and the 

 follicles. The lung lesions correspond closely. Whether they are 

 due to the disease or not must be left undecided. We have frequently 

 seen caseous changes in the lungs of animals free from infection, 

 and they are, perhaps, due to collapse, broncho-pneumonia, and sub- 

 sequent interference of the circulation rather than to the direct action 

 of bacteria. 



The specific bacteria which are the cause of the swine disease are 

 described briefly by Selander, * and according to his description 

 they clpsely resemble hog cholera bacteria in form, motility, growth 

 in gelatine, and appearance in tissues. Their growth on potato is said 

 to resemble that 01 the bacilli of typhoid fever in man, and thus to 

 differ from hog cholera bacilli, f Their effects on the lower animals 

 correspond also, although the descriptions are too brief for careful 

 comparison. There is no mention of the coagulation-necrosis, found 

 constantly in the liver of rabbits inoculated with American hog chol- 

 era. 



In the beginning of the present year (1888), Dr. John Lundgren, 

 professor of veterinary medicine in the University of Stockholm, was 

 sent by the Swedish Government to study swine diseases in this 

 country. He spent several weeks in the laboratory of the Bureau, 

 studying the bacilli of hog cholera. A culture of the swine pest ba- 

 cilli from the Swedish epizootic was at that time subjected to a care- 

 ful examination. 



In gelatine the swine pest germ grows in general like hog cholera 

 bacilli. On the surface of the gelatine the growth is very thin, trans- 

 lucent, of a pearly luster, and spreads more rapidly than the hog chol- 

 era growth. On agar-agar the growth is more abundant and more 

 rapid. Beef infusion, with or without peptone, is converted into a 

 very turbid liquid within twenty-four hours at 95 F., while hog 

 cholera cultures are barely, opalescent at that time, and remain so. 

 Two mice were inoculated from an agar-agar culture of the Swedish 

 germ under the -skin of the back. Both were slightly ill next day. 

 On the second day one was found dead. The cultures from it remained 

 sterile. It probably died from some other cause. The second mouse 

 remained well. On a rabbit the effect was equally negative. No rab- 

 bit survives inoculation with hog cholera bacteria. 



The effect of both germs on pigs was next tried. Two Erlenmeyer 

 flasks, containing each about 300 cubic centimeters (two-fifths pint) of 

 sterile bouillon, were inoculated, one with the American, the other 



* Centralblatt f. Bakteriologie, etc., 1888, i, 362. 



f The chemical reaction of the potato surface, which varies considerably, fre- 

 quently determines the nature of the s growth. Cultures of hog cholera bacilli on po- 

 tato, scarcely visible, may be made very vigorous by making the potato alkaline. 



