458 



INFECTIVE DISEASES. 



characteristic odour. In slightly alkaline broth, and j)eptone with 

 alkaline reaction, in an atmosphere of hydrogen, the gas formed 

 will be sufficient to break the flask if it is sealed up. Kitasato 

 obtained his cultures from pus, by taking advantage of the resist- 

 ance of the spores to high temperatures. By raising cultures 

 to 80° 0. for three-quarters of an hour, the micrococci and bacilli 

 in the mixed culture were destroyed, while the spores of the 

 tetanus bacillus retained their vitality, and then sub-cultures were 

 obtained in a pure state. ■ The spores are said to be killed by 

 exposure to steam for five minutes. A 5 per 

 cent, solution of carbolic acid with '5 per cent, 

 of hydrochloric, will destroy the spores in two 

 hours. Kitasato and Weyl obtained tetaiiin 

 from pure cultures of the bacillus, Brieger 

 having previously obtained it from impure 

 cultures. A tetano-toxin, indol and phenol, and 

 butyric acid a,re also found. Brieger and 

 Frankel attribute the pathogenic properties to 

 a tox-albumin. These products have been de- 

 scribed more fully in a previous chapter (p. 41). 

 A pure-culture produces tetanus in a mouse 

 in twenty-four hours, and rabbits, guinea-pigs, 

 and rats can also be infected. No pus forms 

 at the seat of inoculation, as after inoculation 

 of earth, but the spasms commence in the 

 muscles nearest to the seat of inoculation. A 

 trace of a broth culture will kill a guinea-j^ig, 

 the symptoms developing in three days. 



Kitasato succeeded in making animals im- 

 mune to tetanus, and subsequently the discovery 

 was made that the blood in immune animals 

 will produce immunity in other animals, the 

 explanation being that the toxic principle of 

 the tetanus bacillus induces the formation of 

 tetanus antitoxin ; and if equal parts of the 

 (Feankel and serum of an immune animal, and a fatal dose of 

 Jr'rEiFFEE.) tetano-toxin, are together injected into a healthy 



guinea-pig, tetanus will not follow, showing that the virus has 

 been neutralised. Tizzoni and Cattani found that blood, from an 

 immunised dog was not only capable of completely neutralising the 

 toxic power of filtered cultures, but that the injection of the blood- 

 serum produced immunity in otherwise susceptible animals, except 



1 



Fig. 186.— Puke-cul- 

 TUEE OF Tetanus 

 Bacilli in Grape- 

 SUGAE Gelatine. 

 Four days old. 



