130 The Story of the Bacteria 



Careful cleaning and disinfection of dirty 

 wounds, especially those which are lacerated 

 or punctured, is the proper safeguard against 

 this common bacillus. 



It is finally noteworthy that while inmost 

 of the bacterial diseases the infectious agent 

 is transmitted more or less directly from the 

 sick to the well, and is usually more virulent 

 the more direct and recent the conveyance 

 is, we have in tetanus almost the only ex- 

 ample of pathogenic bacteria widely and 

 persistently contaminating the soil. But it 

 is so particular in its habits that it is only now 

 and then that it falls afoul of human beings. 



It has been possible through experiments 

 on animals to prepare an effective antitoxin 

 for the tetanus poison. Its usefulness is, 

 however, considerably limited by the fact that 

 the symptoms of tetanus do not develop until 

 the germ toxin has gained a powerful hold 

 upon the nervous system, when it may be too 

 late to neutralize it with the artificial anti- 

 body. 



