86 STUDY AND IDENTIFICATION OF BACTERIA 



chymatous and lymphatic organs which are more tolerant of injury than the nerve 

 cells. The dose of tetanus antitoxin as a prophylactic is 1500 units; as a curative 

 agent 5000 to 20,000 units. Recent experience shows that it should be injected 

 intravenously when symptoms have manifested themselves. 



That the disease is due to toxin is shown not only experimentally, but also if 

 spores are carefully freed of all toxin by washing, and then introduced they do not 

 cause tetanus the polymorphonuclears engulfing them. The importance of the 

 presence of ordinary pus cocci in a tetanus wound may be that the activity of the 

 leukocytes in phagocytizing them allows the tetanus bacillus to escape phagocytosis. 

 This would also explain the importance of necrotic tissue in a lacerated wound 

 the phagocytes taking this up instead of tetanus bacilli. The toxin is digested by 

 the alimentary canal juices and infection by that atrium is improbable. The in- 

 fection occurs especially through skin wounds, and also from those of mucous mem- 

 brane. While tetanus is like diphtheria, a disease in which the bacilli are localized 



FIG. 24. Tetanus bacilli showing end spores. (Kolle and Wassermann.) 



and do not spread, yet recently Richardson has obtained tetanus bacilli in pure 

 culture from the tributary lymphatic glands of a "rusty nail" wound of foot. The 

 cultures inoculated into root of tail of a white rate caused the rat's death in forty- 

 eight hours with typical "seal gait" attitude of tetanus in rats. 



The usual period before symptoms occur is fifteen days. The shorter the period 

 of incubation, the more probably fatal the disease. The horse is the most susceptible 

 animal, next the guinea-pig, then the mouse. Fowls are practically immune. 



In examining for tetanus, scrape out the granulation tissue or foreign 

 material from the suspected wound with a sterile Volkmann spoon and 

 insert in a pocket made with scissors in the subcutaneous tissues of the 

 thigh of a guinea-pig. Animal inoculation is the practical method. 

 One may also put some of the suspected material in a Loffler's serum 

 tube. Place in the incubator, under which conditions the cocci and 

 other aerobes grow luxuriantly and enable the tetanus bacillus to de- 



