620 REPORT OP THE COMMISSIONER OP AGRICULTURE. 



oughly mixed by mincing tliom together. Two mice ate of this mixture, and one 

 was found stupid, scarcely able to move about on the following day. The same 

 material was fed a second time. Both were ill on the next day. They crouched, 

 somewhat sprawling, Avith head down, staring coat, and eyes partly closed. On 

 taking them out of the jar they were unable to move; when pushed forward they 

 moved a few stei)S. These symptoms passed away on the third day. Five days 

 after the first feeding one was found dead. The other was fed again six days after 

 the first feeding. It was found dead two days after the last feeding. The first feed- 

 ing had therefore taken etfect. The liver showed the formation of islets of coagu- 

 lation necrosis and was crowded with the bacteria of hog-cholera. The very pe- 

 culiar condition of these animals on the second and third day after feeding can only 

 be explained by assuming the active multiplication of the bacteria in the intestinal 

 canal and the formation of a ptomaine, which, on being absorbed, produced a sys- 

 temic elfect. The invasion of the internal organs themselves from the alimentary 

 canal manifested itself later by the death of the animals and the presence of the in- 

 gested bacteria in the spleen and liver. 



Two additional mice were fed in the same way. One escaped. The other failed 

 to show any symptoms referable to the ptomaine, though fed four times. It re- 

 mained well for over two weeks, when it began to breath laboriously and became 

 very weak. It was killed with chloroform twenty-five days after the first feeding. 

 The spleen was found enormously enlarged, but there were no bacteria on one cover- 

 glass preparation. One lobe of each lung was solid, whitish, crumbling, evidently 

 the result of coagulation necrosis. This mass was crowded with what appeared 

 under the microscope as bacteria of hog-cholera. No cultvu-es were made. This 

 animal, therefore, judging from the enlarged spleen and the necrosed lungs, was 

 also the victim of hog-cholera. Another mouse fed in the same way was dying 

 four days after, but found drowned in the drinking cup next morning, thus pre- 

 venting microscopic examination of the organs. » 



To determ in e whether these animals could be infected with pure cultures, a 

 mouse was fed with bread which had been satxrrated with about J"'= of a liquid 

 cultm-e and dried for an hour in the incubator. The feeding was repeated on four 

 successive days. Seven days after the first feeding the animal was plainly ill, and 

 it died on the following day. This would indicate that the first or second feeding 

 had taken effect. The spleen was enlarged, the vessels of the mesentery very 

 prominent and filled with blood. The bacteria were very abundant in the spleen, 

 moderately so in liver and kidney. A second mouse fed with cultures was found 

 di-owned on the eighth day. 



Two mice, kept in separate jars, were fed with a mass consisting of bread and 

 gelatine culture thoroughly mixed. The gelatine culture laad been prepared by 

 passing a glass rod dipped in a liquid cultm-e over the surface of a layer of gelatine. 

 The gelatine after five days was covered with a tliin opaque layer, consisting of 

 confluent colonies. Both mice ate the dose. One was foimd dead next day in a 

 crouching posture; the poison had evidently killed it in a very short time. .The 

 other did not appear disturbed by the absorption of the ptomaine, but it died from 

 general infection on the sixth day. The spleen was considerably enlarged. Both 

 spleen and liver contained large numbers of hog-cholera bacteria. 



These few experiments show the possibility of an infection of mice 

 through the food, and of the transportation of the disease through the 

 agency of these animals. They show incidentally the effect on the 

 system of the absorption of the ptomaine produced by bacteria in the 

 alimentary canal. 



Feeding was also tried on pigeons by saturating the feed with the 

 culture liquid and allowing it to dry. No marked effect was pro- 

 duced. The feces were unusually liquid and abnormal in appearance 

 for some time. 



Guinea-pigs very susceptible to hog-cholera.— In order to determine the effect of 

 very small doses on guinea-pigs, two animals, Nos. 8 'and 4, which had been kept 

 for more than a month under observation, were inoculated by injecting imder tJie 

 skm of the inner aspect of the thigh about ^tiW" of a culture in meat infusion 

 with 1 per cent, peptone, prepared from the spleen of a pig on the day previous. 

 To obtain such a small dose the culture liquid was diluted with sterile salt solution, 

 and about i" of this injected. On the third day both were imusually quiet and 

 rested together; resph-ation seemed more labored; the animals moved unwillingly 

 when disturbed. No. 3 was found dead on the morning of the eighth day, and No. 

 4 died at noon on the same day. 



