356 Tetanus 



which 0.5 per cent, of hydrochloric acid has been added, destroys 

 them in two hours. They are destroyed in three hours by i • 1000 

 bichlorid of mercury solution, but when to such a solution 0.5 per 

 cent, of hydrochloric acid is added, its activity is so increased that 

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

 exposure to streaming steam for from five to eight minutes is cer- 

 tain 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 baciUus 

 contain indol, hydrogen sulphide, mercaptan and proteolytic fer- 

 ments. In sugar-bouillons the tetanus bacillus ferments dextrose 

 and maltose, giving off lactic and other acids, carbon dioxid and 

 hydrogen gases. Maltose and polysaccharides are not fermented. 



Toxic Products. — ^The most ready method of preparing the toxins 

 for experimental study is to cultivate the bacilli in freshly prepared 

 neutral or shghtly alkaline sugar-free bouillon under conditions of 

 most strict anaerobiosis, at a temperature of 37°C., and then filter 

 the culture through porcelain. FieldJ found the highest degree of 

 toxicity about the sixth or seventh day. It may attain a toxicity 

 so great that 0.000005 cc. will cause the death of a mouse. The aver- 

 age culture has such toxicity that o.ooi cc. 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 2x toxin 



I gram of mouse is destroyed by 13a; toxin 



j 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 Noguchijl 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 will not keep its strength in liquid form under the best con- 

 ditions. 



To keep it for experimental purposes it is advisable to precipitate 



* "Zeitschrift fur Hygiene," xu, p. 225. 



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



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



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



II "Studies from the Rockefellerlnstitute," 1905, v. 



