456 Tetanus 



to cultivate the bacilli in bouillon, at a temperature of 

 37 C., and then filter the culture through porcelain. Field * 

 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. Knorrf gives some interesting comparisons of the 

 susceptibility of different animals, as follows : 



gram of horse is destroyed ty x toxin 



gram of goat is destroyed by 2 x toxin 



gram of mouse is destroyed by 13 x toxin 



gram of rabbit is destroyed by 2,000 x toxin 



gram of hen is destroyed by 200,000 x toxin 



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

 above 6o-65 C. It is also decomposed by exposure to 

 the air and light, so that it is difficult to preserve 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 

 Iceep its strength in liquid form under the best conditions. 



To keep it for experimental purposes it is advisable 

 to precipitate it by supersaturation with ammonium sul- 

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

 scum upon the liquid. It can be skimmed off and dried. 

 Such dry precipitate will retain its activity for months 

 with but little deterioration. 



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, " " tetano- 

 toxin," "tetanospasmin, " and a fourth substance to which 

 no name is given. All were very poisonous and productive 

 of tonic convulsions. Later Brieger and Frankel isolated an 

 extremely poisonous toxalbumin from sugar-bouillon cul- 

 tures of the bacillus. 



The purified toxin of Brieger and Cohn was surely fatal 

 to mice in doses of 0.00000005 gram. The work of these 

 older writers is now so completely superseded by that of 

 others as to be of historic interest only. Lambert % con- 

 siders the tetanus toxin to be the most poisonous substance 

 that has ever been discovered. 



* "Proc. N. Y. Path. Soc.," Mar., 1904, p. 18. 

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

 J "New York Med. Jour.," June 5, 1897. 



