CHAPTER XX 



SOME DISEASES NOT PREVIOUSLY REFERRED TO, WITH A 

 DISCUSSION OF THEIR CAUSATION MICRO-ORGAN- 

 ISMS OF SKIN AND MUCOUS-MEMBRANES 



ABORTION, CONTAGIOUS. This disease of the cow is caused 

 by the B. abortus of Bang, which culturally and serologically is 

 almost identical with M. melitensis (see " Undulant Fever," 

 p. 692). It is a small short Gram-negative bacillus similar to 

 the chicken cholera bacillus, and belonging to the same group. 

 It is difficult to isolate and cultivate. Bang employed melted 

 nutrient agar to which melted gelatin and blood -serum were 

 added. The material introduced into this is well mixed with 

 the medium, the medium allowed to solidify, and the tubes 

 are incubated at blood-heat. In three days numerous colonies 

 form a few millimetres below the surface ; the organism is 

 very specialised in its oxygen requirements, being intermediate 

 between fully aerobic and fully anaerobic, though Bang states 

 that it will grow in an atmosphere of pure oxygen. The colonies 

 are small and compact. The organism does not curdle milk. 

 B. abortus occurs in the vagina of the infected cow and in the 

 heart-blood of the aborted fetus. It causes abortion in the cow 

 and also in guinea-pigs and rabbits, and the condition is con 

 tagious. 



APPENDICITIS. The table 1 on next page shows the usual 

 kinds and relative frequency of the infections in appendicitis. 



It is not improbable that in a still greater percentage of cases 

 a mixture of organisms is present at first, the Bacillus coli subse- 

 quently crowding out the other forms. The Bacillus proteus, 

 B. pyocyaneus, and B. Welchii also occasionally occur. 



1 Battle and Corner, Diseases of the Vermiform Appendix, 1904. 



