216 BACTERIA PRODUCING DIPHTHERITIC INFLAMMATIONS 



FIG. 121 



fissured and misshapen hoof. When treatment is properly applied 

 in the early stages of the disease it is usually cured within ten days. 

 It is very rare for death to occur as a result of foot-rot, although in 

 very virulent outbreaks involving three or four feet of each sheep 

 the affection may terminate fatally within two or three months." 



Secondary necrophorus ulcerations frequently occur on the lips of 

 sheep as a result of infection from licking the ulcerations on the feet. 

 The disease is then termed lip-and-leg ulcer- 

 ation. The contagion may also affect the 

 male and female genitalia, in which case it is 

 known as necrotic venereal disease of sheep. 

 Morphology and Staining Properties. The 

 organism, when found in pus and necrotic 

 material, appears not only as a bacillus, but 

 also in long filaments, which give it the 

 character of a streptothrix. The filament 

 sometimes break up into very short segments, 

 and may then appear like a true streptothrix. 

 The filaments are from 80 to 100 micra in 

 length. The organism is best stained with 

 Loeffler's methylene blue, carbol fuchsin, or 

 carbol thionin. In stained specimens of the 

 filamentous type, unstained spaces often 

 alternate with short, stained, cylindrical rods, 

 causing the filament to look somewhat like 

 a stepladder. In sections of tissues the 

 bacilli, threads, and filaments show a radial 

 arrangement, and they are seen most clearly 

 and in greatest numbers at the boundary 

 zone between the necrotic and the hyper- 

 emic tissues. Branched forms frequently 

 occur. It does not form spores and the 

 long filaments are not motile, but the short 

 bacilli when first seen in pus, exhibit a 

 slight motion. Flagella, however, have not 

 been demonstrated, and the motility is soon 

 lost. 



Cultural and Biologic Properties. The or- 

 ganism is strictly anaerobic and will not grow 

 in the presence of oxygen, It grows best on 

 blood serum or a mixture of agar and blood serum at 30 to 40 C. It 

 also develops on agar and gelatin. In stab cultures in high blood-serum 

 tubes small whitish points appear along the stab after twenty-four to 

 forty-eight hours. When a maximum of growth has been reached, 

 which takes six or eight days, an opaque, grayish-white, cylindrical 

 mass, surrounded by a transparent zone of small individual colonies 

 appears along the stab. Its great susceptibility to oxygen and its 



Leg-and-lip disease in 

 sheep. Infection with Bacil- 

 lus necrophorus. (Dolan.) 



