390 Tetanus 



certain to kill tetanus spores, and this statement has found 

 its way into most of the text-books without discussion. 

 Theobald Smith,* 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 experi- 

 mental study is to cultivate the bacilli in freshly prepared 

 neutral or slightly alkaline sugar-free bouillon under condi- 

 tions of most strict anaerobiosis, at a temperature of 37 

 C., and then filter the culture through porcelain. Field f 

 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. I found the 

 average toxicity such that o.ooi c.c. was fatal to a guinea- 

 pig. KnorrJ 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 13 x toxin 



i gram of rabbit is destroyed by 2,000 x toxin 



i gram of hen is destroyed by 200,000 x toxin 



The toxin is very unstable, and is easily destroyed by 

 heat above 60 C. It is also quickly destroyed by light, 

 especially direct sunlight. Flexnerand Noguchi found that 

 5 per cent, of eosin added to the toxin destroyed it through 

 the photodynamic power of the stain. The toxin is also 

 easily destroyed by electric currents. It is also decomposed 

 by exposure to the air and light, so that it is difficult to pre- 

 serve it for many days. 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 conditions. 



* "Jour. Amer. Med. Assoc.," March 21, 1908, vol. L, No. 12, p. 931. 

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

 J "Munch, med. Wochenschrift," 1898, p. 321. 

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



