BUREAU OF ANIMAL INDUSTRY. 617 



two experiments were made by inoculating with blood directly. Num- 

 erous gelatine cultures of heart's blood had demonstrated the very 

 small number of bacteria compared with the number present in the 

 spleen. 



September 10. — A pig dying -vvith the disease was killed, the heart carefully ex- 

 posed, and the blood drawn with a disinfected hyiaodermic syringe. Nos. 329 and 

 333 received subcutaneously 5" each, one half in each thigh. No. 329 in a few 

 days lost its appetite, became weak and stupid. Found dead October 5. Slight 

 local swelUng at the points of inoculation; superficial inguinals greatly enlarged; 

 hypostatic congestion of limgs; complete necrosis of mucous membrane in caecum; 

 large scattered ulcers in colon, showing as whitish patches on serous surface and 

 encircled by a crown of enlarged blood vessels; bacteria in spleen. 



No. 333, slightly ill for a time; fully recovered. Died December 2 with no other 

 lesions than engorgement of liver. No signs of former ulceration.^ 



A second experiment was made in the same way: 

 October 13.— Nos. 324 and 325 inoculated as in the preceding experiment, 10" of 

 blood being used for each animal. No. 324 was found dead November 1, after being 

 off feed for a time. Deeply reddened skin over caudal half of abdomen; extremely^ 

 large and serously infiltrated superficial lymphatics; on section, hemorrhagic points.' 

 At point of inoculation the connective tissue is infiltrated; 50'^" to 75" clear amber 

 serum in abdominal cavity; papillte of kidneys deeply reddened; slight congestion, 

 but no ulceration in large intestme; lymphatics in general moderately tumefied and 

 congested. 



No. 325 fovmd dead October 29. Reddening of skin as in 324; extravasation in 

 connective tissue; spleen greatly enlarged, purplish; lymphatics of thorax and abdo- 

 men purplish, enlarged; petechise on section of kidney and in pelvis, also over en- 

 tire surface of epicardium; lung tissue mottled both on sm-face ahd on section with 

 purple spots, due to blood extravasation into alveoH, so that it scarcely floats. Mu- 

 cous and serous surface of small intestine dotted with petechiae; small hemorrhages 

 on the surface of the mucous membrane and into the submucous tissue of the caecum 

 and upper colon. Ulceration beginning. 



These results are more positive than those obtained with cultures, 

 and on first thought we may be inclined to attribute them to a greater 

 virulence of the germs in the injected blood. This view needs further 

 confirmation, however. The injected blood coagulating in the con- 

 nective tissue contains in it the bacteria, which are not only protected 

 from the aggression of cellular elements, but have actually a store of 

 nourishment upon which they may live and multiply. No such ad- 

 vantages are presented to bacteria suspended in liquids which are 

 readily absorbed, leaving them to the mercy of the tissues surround- 

 ing them. The local reaction in the above animals was very insig- 

 nificant compared with that produced by liquid cultures. In order 

 to come to any conclusion, it would be desirable to add a few bacteria 

 from cultures to fresh blood, and observe the relative virulence in the 

 way indicated above. 



Taking the foregoing results into consideration, the alimentary 

 canal must be considered as the most vulnerable point for the entrance 

 of the bacterium of hog-cholera. It is probably the chief, if not the 

 only, entrance of the virus when the infection takes i^lace among herds. 

 The occasional occurrence of lung lesions as extensive hepatization 

 in advanced cases of hog-cholera suggested to Klein the name of 

 pneumo-enteritis. In the many cases carefully examined at the exper- 

 imental station the lung lesion did not appear to surpass in severity 

 those of the internal viscera and the lymphatic system. In the great 

 majority of animals lung-worms were usually found associated with 

 localized atelectasis. The collapsed portions had a red flesh color. 

 Many cases of chronic hog-cholera, associated with extensive ulcer- 

 ation of the large intestine, had normal lungs. On the other hand, 

 cases of a very acute hemorrhagic type, produced by feeding infec- 



