TETANUS. 63 



advisable to carefully autoclave all material going into bacterial 

 vaccines, such as salt solution, bottles for holding, etc. 



Tetanus seems to grow better in symbiosis with aerobes; hence a 

 lacerated dirty wound with its probable contamination with various 

 cocci, etc., and its difficulty of sterilization, offers a favorable soil. 

 The tetanus bacillus gives rise to one of the most powerful poisons 

 known; it is a soluble toxin like diphtheria toxin, and it is estimated 

 that 1/300 of a grain is fatal for man. 



Rosenau has established an antitoxin unit for tetanus which has 

 the power of neutralizing one-thousand minimal lethal doses. Con- 

 sequently it is a unit ten times as neutralizing as the diphtheria anti- 

 toxin one. The antitoxin of tetanus is less efficient than that of 

 diphtheria for the following reasons: 



1. There is about three times as great affinity in vitro between 

 diphtheria toxin and antitoxin than is the case with tetanus. 



2. The tetanus toxin has greater affinity for nerve-cells than for 

 antitoxin. 



3. Treatment with antitoxin is successful after symptoms of 

 diphtheria appear. With tetanus it is almost hopeless after the 

 disease shows itself. Hence the importance of the early bacteriological 

 examination of material from a suspicious wound (rusty nail). 



4. The tetanus toxin ascends by way of the axis cylinder, and the 

 antitoxin being in the circulating fluids cannot reach it, whereas with 

 diphtheria both toxin and antitoxin are in the circulation. Diphtheria 

 also selects the cells of parenchymatous and lymphatic organs which 

 are more tolerant of injury than the nerve cells. 



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 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 infection occurs especially through skin wounds, 



