344 Tetanus 



spores are destroyed in thirty minutes. According to Kitasato,* 

 exposure to streaming steam for from five to eight minutes is 

 certain to kill tetanus spores, and this statement has found its way 

 into most of the text-books without discussion. Theobald Smith, f 

 however, has studied several cultures of the organism and finds that 

 its resistance to heat is much greater, and that in one case seventy 

 minutes' exposure to streaming steam did not kill all of the spores. 



Metabolic Products. — Bouillon cultures of the tetanus bacillus 

 contain acids, proteolytic ferment, and several toxic substances, 

 of which tetanospasmin and tetanolysin are best known. The 

 toxic products are apparently all soluble. No endotoxin is known to 

 be formed. 



The most ready method of preparing the toxins for experimental 



study is to cultivate the bacilli in freshly prepared neutral or slightly 



alkaline sugar-free bouillon under conditions of most strict anaero- 



biosis, at a temperature of 37°C., and then filter the culture through 



porcelain. Fieldf found the highest degree of toxicity about the 



sixth or seventh day. It may attain a toxicity so great that 0.000005 



c.c. will cause the death of a mouse. The average culture has such 



toxicity that o.ooi c.c. is fatal to a guinea-pig. Knorr§ gives some 



interesting comparisons of the susceptibility of different animals, as 



follows: 



I gram of horse is destroyed by x toxin 



I gram of goat is destroyed by ix toxin 



I gram of mouse is destroyed by 13a; toxin 



I gram of rabbit is destroyed by 2,000a; toxin 



I gram of hen is destroyed by 200,000a; toxin 



The toxin is very unstable, and is easily destroyed by heat above 

 6o°C. It is also quickly destroyed by light, especially direct sun- 

 light. Flexner and Noguchi|| found that 5 per cent, of eosin added 

 to the toxin destroyed it through the photodynamic power of the 

 stain. It is also easily destroyed by electric currents. The best 

 method of keeping it is to add 0.5 per cent, of phenol, and then store 

 it in a cool, dark place, in bottles completely filled and tightly corked. 

 It wiU not keep its strength in liquid form under the best conditions. 



To keep it for experimental purposes it is advisable to precipitate 

 the toxin from the bouillon by supersaturation with ammonium sul- 

 phate, which causes it to float upon the liquid in the form of a sticky 

 brown scum that can be skimmed off and dried. Such dry precipi- 

 tate retains its activity for months. 



From cultures of tetanus bacilli grown in various media, and from 



the blood and tissues of animals affected with the disease, Brieger 



succeeded in separating "tetanin," "tetanotoxin," tetanospasmin," 



and a fourth substance to which no name is given. All were very 



* "Zeitschrift fiir Hygiene," xil, p. 225. 



f "Jour. Amer. Med. Assoc," March 21, 1908, vol. l, No. 12, p. 931. 



% "Proc. N. Y. Path. Soc," March, 1904, p. 18. 



§ "Miinch. med. .Wochenschrift," 1898, p. 321. 



II "Studies from the Rockefeller Institute," 1905, v. 



