EEPOKT OF THE BUKEAU OF ANIMAL INDUSTRY. 143 



or faintly cream color. In order to detect its presence it was neces- 

 sary to catch, the reflection of the light at a certain angle. This posi- 

 tive result among so many negative ones may be due to differences 

 in the chemical reaction of the potato used. Growth in gelatine at 

 the temperature of the room took place in some instances, in others 

 it failed, so that it could not be depended upon and agar was used 

 almost exclusively. Its resistance to drying was tested with the aid 

 of methods detailed in former reports. Cover-glasses sterilized by 

 heat and placed under a sterilized, inverted, and plugged funnel re- 

 ceived a little of the growth on agar or bouillon peptone. A few 

 hours suffice to dry them out thoroughly. Twice a day cover-glasses 

 were dropped into culture tubes containing bouillon to note any mul- 

 tiplication that might take place. The dried germs from agar cult- 

 ures were capable of multiplying in the bouillon up to the sixth or 

 seventh day. Bouillon into which cover-glasses were placed after 

 that time remained uniformly clear. When dried bouillon cultures 

 were tested in the same way the germs were found to be dead after 

 thirty-six hours. It seems, therefore, that germs massed together, 

 as in agar cultures, can withstand destruction by drying longer than 

 those disseminated in liquids. While the former lived in the dried 

 state about six days, the latter lived only one and a half days. The 

 same curious fact has been determined with reference to hog cholera 

 bacilli. Thus in a recent laboratory experiment hog cholera bacilli 

 from bouillon peptone cultures lived thirty-six days in a dried con- 

 dition ; those from agar cultures twenty days longer. 



Pathogenic properties. As in biological characters so in pathoge- 

 nic power, the Iowa germ seems to agree with the swine plague bac- 

 teria of former investigations. Its effect upon rabbits has been de- 

 tailed in the preceding pages. Briefly it may be said to produce in 

 them suppuration and hemorrhagic lesions in the subcutis and in the 

 peritoneal cavity. More rarely rfc produces a true septicaemia, which 

 must be regarded simply as a heightened effect. 



Their pathogenic effect on pigs was tried in various ways by hypo- 

 dermic, intra-thoracic, and intra-abdominal injection of pure cult- 

 ures. 



December 1, one pig, about five and one-half months old (No. 88), received sub- 

 cutaneously into each thigh 5 cubic centimeters of a bouillon peptone culture de- 

 rived originally from Iowa pig No. 8. No result. 



At the same time No. 86, of the same age, was inoculated into the lungs ; 9 cubic 

 centimeters of a culture from the same source was injected through the chest wall 

 into the right lung with a hypodermic syringe having a needle about 3 inches long. 

 The skin at the place of injection was first disinfected with V& per cent, solution of 

 mercuric chloride. 



The pig was found dead next morning. At the autopsy the superficial inguinal 

 glands were found with reddened cortex, the spleen large and gorged with blood. 

 One or two ounces of slightly cloudy serum in the abdominal cavity; a few threads 

 of fibrin stretched over the ventral surface of intestines. The meso-colon attach- 

 ing the two middle loops of colon deeply reddened ; the glands of meso-colon and 

 caecum also deeply congested throughout the parenchyma. The mucosa of the 

 colon slightly reddened ; the large patch of follicles near the valve considerably 

 reddened. Gastric glands with cortex and more or less of parenchyma reddened. 



In right pleura! sac 2 to 3 ounces of blood-stained serum; none in left side. The 

 entire pleural lining of the right side reddened and covered by a very delicate net- 

 work of exudate, which is easily scraped together into a soft, pulpy, yellowish mass. 

 Both lungs collapsed, but considerably congested. 



In the pleural exudate and in the parenchyma of the right lung are large num- 

 bers of polar-stained bacteria. In the spleen an immense number of the same or- 

 ganisms are present. In cultures obtained from this organ they are identical with 

 those injected on the preceding day. 



