72 STUDY AND IDENTIFICATION OF BACTERIA 



When the toxin is introduced, it requires a period of incubation of 

 twelve to twenty hours. Symptoms of gastrointestinal disorder may 

 come on shortly after the ingestion of the toxin containing food, these 

 however are not the specific manifestations, as are the eye symp- 

 toms, etc. 



An important point is that ham may not appear decomposed and yet contain 

 many bacilli and much toxin. It is a very potent toxin as little as one-thousandth 

 of a c.c. may kill a guinea-p'ig. In man the toxin is apparently absorbed from the 

 alimentary canal. For diagnosis inject an infusion of the ham or sausage which 

 was eaten of into a guinea-pig, and characteristic pupillary symptoms with death 

 by cardiac and respiratory failure will result. 



Cultures may be made in glucose agar. 



The culture is disrupted by gas. Incubation at room temperature and in the 

 dark is necessary. There is a rancid odor. The characteristic point is the pro- 

 duction of a powerful soluble toxin which produces symptoms when no bacilli are 

 present. 



B. tetani (Nicolaier, 1885; Kitasato, 1889). This is the most 

 important organism of the anaerobic spore bearers. Its characteristics 

 are the tetanic symptoms produced by the toxin and the strictly termi- 

 nal drum-stick spores. Spores are difficult to find in material from 

 wounds infected with tetanus, but readily develop in cultures. Prior to 

 the formation of spores the organism is a long thin bacillus (4 X 0.4^) . It 

 is motile and Gram positive. It liquefies gelatin slowly and does not 

 coagulate milk. 



Theobald Smith recommends growing it in fermentation tubes containing 

 ordinary bouillon, but to which a piece of the liver or spleen of a rabbit or guinea-pig 

 has been 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 37 C. 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 uncertainty 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 bac- 

 terial 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; 



