REPORT OF THE BUKEAU OF ANIMAL INDUSTRY. 99 



specific nature was tested by inoculation into mice, both of which died on the fifth 

 day with characteristic lesions. 



Pig No. 386 was transferred to the infected pen at the same time. It became af- 

 fected after a three weeks' stay in the infected pen, and died of hog cholera April 15. 

 From the spleen the specific bacteria were obtained as pure cultures, and inoculation 

 into mice produced the characteristic disease. 



Pig No. 366 is another instructive case in which the two diseases were present. 

 The animal had been put into a pen in which swine plague had to all appearance 

 died out two months ago, but in which pigs were dying of hog cholera at intervals 

 of a few weeks. 



This animal had been inoculated into the lungs through the chest wall on October 

 30, 1886, with one-half cubic centimeter of liquid culture of swine plague bacteria, 

 obtained originally from Sodorus, 111. A pig inoculated subcutaneously at the same 

 time died from its effects, but the former showed, no signs of disease excepting a gen- 

 eral unthrifty condition. The animal did not increase in size. As late as June 4, 

 1887, it was transferred to the pen above mentioned. It was injured by fighting 

 with other pigs in the same pen June 21. Up to this time no change could be ob- 

 served. It pecame very weak and died June 29, twenty-five days after exposure. 



Autopsy immediately after death. Skin slightly reddened over pubic region; 

 lymphatics but very slightly enlarged and congested; spleen enlarged, friable. In 

 the caecum and upper colon are from 12 to 15 small ulcers from one-quarter to one- 

 eighth inch across. The mucosa itself is quite deeply congested. 



The whole pleural surface of lungs lightly glued to chest wall ; the attachment 

 being readily severed, the pleura is found covered with a pale yellow exudate. The 

 odor from the thorax is strongly putrefactive. The pericardium is thickened and 

 everywhere adherent to the heart. The various lobes of the lungs are glued together 

 by a scanty exudate. The ventral and cephalic lobe and the ventral (ventro-cephalic) 

 portion of the principal lobe of each lung solidified. The remaining dorsal portion 

 is dark red, hypostatic. Trachea and bronchi filled with yellowish foam. 



The right cephalic and the ventral lobe have a yellowish-white appearance. On 

 section the tissue is found transformed into a homogeneous mass cutting like dry 

 cheese. These caseous masses are distributed as isolated nodules from the size of a 

 pea to that of a bean, or else in the form of a thick net-work including dark-red, 

 hepatized groups of lobules. The left cephalic lobe has not yet advanced to this 

 caseous stage. In the left ventral lobe the process is begun as whitish arborescent 

 lines with occluded bronchioles and alveoli. The thickened pericardium being re- 

 moved, the surface of the heart was found covered by a firmly adherent deposit 

 about 1 millimeter thick, villous, scraped away with difficulty. Over left ventricle 

 a rather pale clot one-half centimeter thick. 



These lesions indicated a severe form of swine plague. The intestinal ulcers 

 pointed to the existence of hog cholera also. This was to be expected, since the pen 

 was thoroughly infected with the latter disease. The bacteriological investigations 

 demonstrated the presence of both micro-organisms, the bacteria of hog cholera in 

 the spleen, those of swine plague in the lung tissue and pericardia! cavity. 



Cover-glass preparations from the hepatized lung tissue show immense numbers of 

 bacteria, chiefly oval in form. A moderate number were found in the epicardial exu- 

 date. A rabbit and three mice were inoculated with a little semi-fluid matter scraped 

 from a cut surface of the hepatized lung tissue, the former in the ear, the latter be- 

 neath the skin of the back ; a fourth mouse was inoculated from the epicardial exu- 

 date. The rabbit died in forty-eight hours, apparently well a few hours before death. 

 At the point of inoculation on both ears a small abscess, the pus containing long spore- 

 bearing bacilli. Intense peritonitis. A thin, whitish, pasty layer covers the fiver, 

 spleen, and caecum. The latter and portion of the colon covered thickly with sub- 

 peritoneal hemorrhagic points and patches. Lungs cedematous. The peritoneal exu- 

 date contained immense numbers of oval bacteria. In the blood none could be 

 found. A gelatine tube culture from the former and a beef infusion culture from 

 the latter contained the characteristic swine plague bacteria. These had thus been 

 isolated from the various putref ying forms by passing through the body of the rabbit. 

 The three mice inoculated from lung tissue died, two on the second and one on 

 the third day. The latter, owing to the great heat, was already decomposed, hav- 

 ing died during the night. The blood of the other two contained only the swine 

 plague bacteria ; roll cultures* made therefrom confirmed this. The fourth mouse 



* Roll cultures are made by coating the inside of test tubes with gelatine which 

 has been inoculated with bacteria to be studied. For a description of the method 

 see E. Esmarcn, Zeitschrift fur Hygiene, 1, 293. This more convenient method had 

 to be used, owing to the very high temperature of the laboratory in summer when 

 all cultures in gelatine had to be kept in a refrigerator or ' ' cold box." The ordinary 

 plate cultures occupy too much space. 



