BUREAU OP ANIMAL INDUSTRY. 661 



micrococcus. Bits of the spleen introduced beneath the skin of the dorsum of two 

 mice made tiiem ill for a few days. Both finally recovered. 



Besides the cultures mentioned in the autopsy notes at least ten others were made 

 at the time bv piercing the spleens Avith a i)latinum wire and then piercing with it 

 tubes of gelatine or drawing it over the surface of tubes of agar-agar. None of these 

 showed any signs of growth, thus confirming the supposition, derived from the exam- 

 ination of cover-glass preparations, that the specific microbes are either entirely ab- 

 sent from the spleen or else are present in very small numbers. 



T]ie lesions found in all but three cases, in which the ulceration of 

 the large intestine was present, were not sufficiently uniform to war- 

 rant the diagnosis of hog-cholera. Viewed by the light of later ob- 

 servations, it seems highly probable that the remainder of the ani- 

 mals were affected with a different malady, due to the presence of the 

 microbe to be described later on. The ecchymosis of the large intes- 

 tine and the congestion and tumefaction of the lymphatics generally 

 differed from the lesions which we have found in hog-cholera. The 

 absence of bacteria from the tissues is also suspicious. There was 

 moreover a partial cirrhosis of the liver in most of the animals exam- 

 ined which we have never encountered in hog-cholera. We must 

 remember, however, that of these eight cases live were killed, per- 

 haps in the early stages of the disease, before the lesions were well 

 marked. Leaving these observations for future interpretation, when 

 more cases have been examined we will proceed to a description of 

 the bacteriological investigations. 



In a few among a large number of tubes bacteria were present, 

 Nearly all were found harmless when inoculated into animals very 

 susceptible to hog-cholera. In two tubes inoculated with bits of 

 spleen from No. 6 two microbes were found which deserve attention. 



One grew in both tubes, which was more carefully examined , because it resembled 

 the bacterium of hog-cholera very closely. In h(iuid media it is actively motile 

 and simulates the form of a bacillus. When stained, however, each individual is 

 resolved into a pair of ovals or very short rods with rounded extremities. A deeply 

 stained narrow border surrounds a comparatively pale body. There seems to be 

 slightly more stained material at the two extremities than in the bacterium already 

 fully described in the last report. It seems a trifle longer than the latter form, but 

 on attempting to confirm this impression by measurement the dimensions were 

 found practically the same. Sown on gelatine plates the colonies appear within 

 twenty-four hours and grow quite rapidly. The deep colonies are spherical, with 

 smooth outline and homogeneous disc. The surface colonies apipear as irregular 

 patches, spreading very quickly, and, as a inale, grovving far more vigorously than 

 the deep colonies. In tubes containing nutrierit gelatine tlie isolated colonies in the 

 depth of the needle track may grow to the size of pins' heads. On the surface a flat, 

 thin, pearly layer rapidly extends from the point of inoculation, and in from one to 

 two weeks may have covered the entire surface. The margins are irregularly scal- 

 loped and lobed, the entire layer often simulating the frost flowers onwindows or 

 lace work (Plate V, Fig. 2). On potato, a thick straw-colored shining layer of nearly 

 smooth surface forms, which grows very vigorously and gradually covers the entire 

 cut surface of the potato with a layer 2"'"°' "thick. This growth is brighter in color 

 and more abundant than appears in the potato culture of tJie bacterium of hog- 

 cholera. Cultivated in liquids, such as beef mfusion with 1 per cent, peptone, the 

 medium becomes very turbid within twenty-four liours. A thui pellicle appears, 

 which soon becomes a thick membrane. A cream-colored deposit forms and accumu- 

 lates to a considerable extent, while the liquid remains turbid. It will be remem- 

 bered that the bacterium of hog-cholera grows very feebly in comparison. 



No resistant spore state was found, for tubes exposed to .58'^ C. for fifteen minutes 

 remained sterile; those exposed ten minutes became turbid. The pale, unstained 

 central portion of the bacterium simulates very strikingly the appearance of an en- 

 dogenous spore, yet they all succumb to the temperature of 58" C. , as described. A 

 peculiar property not common to the hog-cholera bacteria described is the coagu- 

 lation of the casein of milk. If a tube of this liquid, sterUized by discontinuous 

 boihng, be inoculated, it will be solidified within twenty-four hours. The coagulum, 

 contracting later on, leaves a shallow stratum of watery liquid near the siirface. 



