446 Tetanus. 



experience also proves that tetanus, under natural conditions, 

 appears by preference associated with such wounds as are ac- 

 companied by destruction of tissues, hemorrhage or accumula- 

 tion of a purulent secretion. 



Spores occurring free in nature do not contain toxins, 

 although an infection occurs with spore-containing earth in 

 healthy tissue; this finds its explanation in the fact that, to- 

 gether with the tetanus spores, other bacteria gain entrance 

 into the tissues, finding here a favorable medium for their de- 

 velopment, and consequently causing disease of tissue which 

 then furnishes a suitable medium for the growth of the tetanus 

 organism. Spore-containing earth loses its power of infection 

 when heated to 85° C. ; such a temperature is not sufficient 

 to kill the spores, but it does destroy other bacteria present 

 in the earth. Earth that has been freed of its infective char- 

 acter by heating may again produce tetanus if simultaneously 

 with its subcutaneous injection there are introduced cultures 

 of bacteria grown from the earth before heating it. That is why 

 tetanus develops sometimes after comparatively slight injuries, 

 for instance after the introduction of a wooden splinter or 

 following a superficial suppurating wound covered by a scab. 



Influences which reduce the resistance of the tissues and 

 perhaps paralyze the activity of phagocytes favor infection, 

 and in this sense colds or overheating (hard work in summer 

 heat) may be of importance. 



The apparently spontaneous cases which do not appear 

 immediately associated with any injuries are at least partly 

 explained by the latency of the tetanus spores in the animal 

 body, in that spores which have penetrated into the body some 

 time previously are kept alive enclosed in cells, and later germi- 

 nate under the influence of a favoring factor (disease, colds, 

 overheating, muscular exertion) and cause a multiplication of 

 the bacilli. 



Vaillard & Rouget found viable and virulent spores SY2 months after injection 

 of spores into the bodies of guinea pigs, and Tarozzi also demonstrated that in 

 animals infected subcutaneonsly with spore-bearing cultures of tetanus the 

 spores frequently gain admission to the blood, migrating to organs far removed 

 from the original site of infection, where they may remain latent for 314 months 

 or longer. When favorable conditions arise, particularly necrosis of spore- 

 containing tissue, the latent spores are revived to vegetation and may cause 

 tetanus. Soprana, Canfora, also Reinhardt & Assim have arrived at similar 

 conclusions in their studies on the latency of tetanus spores. As the intesti- 

 nal evacuations of herbivora frequently contain spores there is always the 

 possibility that thej may occasionally gain entrance to organic tissue, where they 

 multiply and give impetus to the formation of antitoxins. This would explain 

 Roemer's findings in cattle over two years of age in which the blood serum 

 frequently showed antitoxin in demonstrable quantities (1/2400 to 1/50 units per ec). 



The influence of an increase of the body temperature on the development of 

 tetanus was demonstrated by Vincent who raised the body temperature of guinea 

 pigs in the thermostat or incubator to 40.5°C., subsequently injected spores that 

 had been heated to 85'C. and caused fatal tetanus in 2 to 3 days. The bacilli 

 were found disseminated through the entire body. 



Germination and multiplication of bacilli usually occur ex- 

 clusively at the site of infection and therefore bacilli are rarely 



