

BACTERIA IN THE SOIL 1 71 



In some countries, and in certain localities, the bacillus of 

 tetanus is a very common habitant of the soil, and when one 

 thinks how frequently wounds must be more or less con- 

 taminated with such soil, the question naturally arises, How 

 is it that the disease is, fortunately, so rare ? Probably we 

 must look to the advance of bacteriological science to answer 

 this and similar questions at all adequately. Much has re- 

 cently been done in Paris and elsewhere to emphasise the 

 relation which other organisms have to such bacteria as 

 those of typhoid and tetanus. When considering typhoid, 

 we saw that in addition to the presence of the specific germ 

 other conditions were requisite before the disease actually 

 occurred. So in tetanus, Kitasato and others have pointed 

 out that the presence of certain other bacteria, or of some 

 foreign body, is necessary to the production of the disease. 

 The common organisms of suppuration are particularly ac- 

 cused of increasing the virulence of the bacillus of tetanus. 

 How these auxiliary organisms perform this function has 

 not been fully elucidated. Probably, however, it is by 

 damaging the tissues and weakening their resistance to such 

 a degree as to afford a favourable multiplying ground for the 

 tetanus. It is right to state that some authorities hold that 

 they act by using up the surrounding oxygen, and so favour- 

 ing the growth of tetanus. 



Quarter Evil (or symptomatic anthrax) is a disease of 

 animals, produced in a manner analogous to tetanus. It is 

 characterised by a rapidly increasing swelling of the upper 

 parts of the thigh, sacrum, etc., which, beginning locally, 

 may attain to extraordinary size and extent. It assumes a 

 dark colour, and crackles on being touched. There is high 

 temperature, and secondary motor and functional disturb- 

 ances. The disease ends fatally in two or three days. 



Slight injuries to the surface of the skin or mucous mem- 

 brane are sufficient for the introduction of the causal bacil- 

 lus. This organism is, like tetanus, an anaerobe, existing 



