BACILLUS TETANI 483 



explanation for this possibility. They find that phagocytosis plays 

 an important part in the removal of tetanus spores which are injected 

 without tetanus toxin or other irritating substances. Polymorpho- 

 nuclear leukocytes engulf free tetanus spores. If, however, the spores 

 are introduced into the body in collodion capsules, thus protecting 

 the organisms from the leukocytes, the tetanus spores develop into 

 bacilli there, form toxin, and. produce tetanus. If tetanus spores are 

 mixed with lactic acid, with tetanus toxin, or with other irritants, or 

 even injected with saprophytic bacteria, the spores develop into tetanus 

 bacilli, produce toxin and kill the animal. 



Bacteriological Diagnosis. 1. Microscopical. Smears made from 

 the pus of wounds in suspected cases of tetanus may show the charac- 

 teristic spores of the tetanus bacilli. The organisms, however, are 

 usually present in very small numbers and several smears should be 

 made. Negative results do not prove the absence of the tetanus 

 bacillus. 



2. Cultural. Pus from wounds scraped out with sterile curettes, 

 or suspected material is placed in fermentation tubes containing bits 

 of sterile tissue, according to Theobald Smith's method mentioned 

 above, incubated for forty-eight hours and examined -microscopically 

 for typical spores. If these are found the material is heated to 80 

 C. for thirty minutes to kill vegetative forms and then reinoculated 

 to obtain growths of the organism. 



3. Toxin. Inoculation of material containing tetanus bacilli and 

 other organisms into slightly alkaline broth (sugar-free) grown anae- 

 robically for six or eight days will lead to toxin formation even if 

 other bacteria are present. Inoculation of this toxic broth into mice 

 will frequently give positive results. Broth obtained according 

 to the Theobald Smith method in Step 2 also should be inoculated 

 into mice if the preliminary microscopic examination shows tetanus 

 spores. 



4. At times tetanus toxin occurs even in the blood of the patient, 

 provided no antitoxin has been administered; 1 c.c. of this blood 

 inoculated into a mouse may occasionally produce characteristic tetanic 

 phenomena. 



Prophylaxis. Any wound likely to be a suitable portal of entry for 

 the tetanus bacillus should be regarded as potentially dangerous and 

 tetanus antitoxin should be administered promptly as a prophylactic 

 measure. Fifteen hundred units of tetanus antitoxin is the ordinary 

 prophylactic dose in such cases, For curative doses 3000 to 20,000 



