670 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



could not be found. Three tubes of culture liquid were inoculated 

 each with throe to four drops of the blood from the heart. They 

 remained sterile. Bits of spleen and liver about -j'"' cube were 

 dropped into tubes. They also remained sterile. 



No. 374 lived longer, became very weak and stupid, and finally 

 was unable to rise. Eleven days after inoculation it died. At one 

 of the points of inoculation there was a firm, tough tumor. The le- 

 sions were very similar to those just given, but less pronounced. 

 There was but slight icterus of the connective tissue. Serum in per- 

 icardial cavity and fat about heart stained yellow. Urine gives very 

 easily the reaction for bile pigments. Lungs hypostatic. Both sides 

 of heart filled with black coagula. Liver in the same condition as 

 that of No. 375. Gall bladder as above. The common duct was 

 patent and still bile-stained. Venous stasis of portal system but 

 slightly marked. Intestinal tract normal. Four liquid cultures of 

 blood from the heart remain sterile. Into one a large coagulum had 

 been dropped. Two pieces of liver and two from the spleen fail to 

 induce any bacterial growth whatever in the liquids into which they 

 are dropped. The check animals remained well for a month after. 



The uniform success in producing most severe cases of hog-cholera 

 by feeding pure liquid cultures of hog-cholera bacteria to pigs which 

 had been deprived of food for 24 to 36 hours led to the inference that 

 the same result might be expected from the microbe of pneumonia, 

 provided it was at all capable of being infectious by way of the 

 intestinal tract. 



December 19. — Two pigs (385, 386) were deprived of food for 82 hours. No. 885 

 then received a Uter of beef broth containing 10 grams of sodium carbonate to in- 

 crease the alkalinity of the stomach. Each was thereupon fed with 250''^ of a cult- 

 ure of the pneumonia microbe in simple beef infusion six days old. This dose was 

 mixed vsdth beef broth to make one liter. Up to the time of writing (January 27) 

 not the slightest disturbance in health has been manifest. Three pigs fed about 

 the same time and in the same way with cultures of hog-cliolera bacteria all suc- 

 cumbed, with very severe lesions of the intestinal tract. (Pag^614.) 



This microbe had thus produced, when injected beneath the skin 

 in quantities not less than 5"° of culture liquid (beef infusion with 1 

 per cent, peptone neutralized) , an acute cirrhosis of the liver in seven 

 out of ten pigs. The pathological changes in most cases were so severe 

 as to check the formation of bile entirely. We must provisionally 

 accept the theory that the injected microbes exert their patho- 

 genic power chiefly vqyon the liver. Perhaps the germs are deposited 

 there by the blood current and cause an acute inflammatory hyper- 

 plasia of the interlobular tissue. In contracting, the portal vessels 

 and bile ducts are compressed so as to become impervious. This pro- 

 duces a venous congestion of the abdominal organs, which pour their 

 blood into the portal vein, and a generalized icterus, caused perhaps 

 by the retention of the bile elements in the blood, as well as their re- 

 absori^tion from the liver. Meanwhile the bacteria themselves are 

 destroyed in the tissues, so that at the death of the animal none can 

 be found even by means of the most delicate methods of cultivation. 



That the three pigs which did not succumb to the inoculation were 

 not affected is not warranted, as the following experiment shows : A 

 pig was inoculated ]>y injecting into the traclioa a culture of this mi- 

 crobe. The pig remained well for several weeks, when it was killed 

 for examination. At the autopsy it was found that owing to tlio 

 thick layer of fat in the neck the injection did not enter the trachea. 

 A tumor almost as large as a hen's egg had formed by the side of the 



