TETANUS 85 



introduced at the junction of the closed arm and the open bulb. By this method 

 spores develop rapidly in from twenty-four to thirty-six hours. Sporulation is 

 most rapid at 37C. As there is always liability to postmortem invasion of viscera 

 by ordinary saprophytes, Smith recommends that great care be taken not to handle 

 the animal roughly in chloroforming and in pinching off pieces of the organ at 

 autopsy. The animal must be healthy, and the tubes to which the piece of tissue 

 is added must be proven sterile by incubation. Smith calls attention to the un- 

 certainty of the temperature at which tetanus spores are killed. He shows that 

 some require temperature only possible with an autoclave. In view of the danger 

 of tetanus, it is 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 J^joo grain is fatal for man. 



There are 2 toxins, tetanospasmin and tetanolysin, but the former 

 is the important one. Tetanus toxin is twenty times as poisonous as 

 dried cobra venom. 



The antitoxin is produced by injecting horses with increasing doses of tetanus 

 toxin, following a preliminary dose of 5000 antitoxin units. An important point 

 is that a horse used for the production of diphtheria antitoxin may become infected 

 with tetanus and his blood contain enough tetanus toxin to kill. A number of 

 children in St. Louis died of tetanus as the result of such an accident. 



Rosenau has established an antitoxin unit for tetanus which has the power of 

 neutralizing 1000 minimal lethal doses. Practically, it is ten times the least 

 quantity of antitetanic serum necessary to protect the life of a 350 grams 

 guinea-pig from a test dose of tetanus toxin furnished by the hygienic laboratory. 

 (The necessity of some definite unit is apparent when tests have shown that serum 

 stated to contain 6,000,000 units per c.c. only had a value of 90 of the official 

 American units.) Consequently it is a unit ten times as neutralizing as the diph- 

 theria antitoxin one. The antitoxin of tetanus is less efficient than that of diph- 

 theria for the following reasons: 



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

 and antitoxin as 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 impor- 

 tance 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, wheras with diphtheria both toxin 

 and antitoxin are in the circulation. Diphtheria also selects the cells of paren- 



