BACILLUS TETANI 585 



obtained and introduced with them into the tissues of the 

 animal at the time of inoculation. In support of the latter 

 hypothesis; mice have been inoculated with pure cultures 

 of this organism; after one hour the point at which the 

 inoculation was made was excised and the tissues cauterized 

 with a hot iron; notwithstanding the short time during 

 which the organisms were in contact with the tissues and 

 the subsequent radical treatment, the animals died after 

 the usual interval and with the typical symptoms of tetanus. 



The poison produced by the tetanus bacillus, and to 

 which the symptoms of the disease are due, has been isolated 

 and subjected to detailed study; some of its toxic peculiari- 

 ties, as given by Kitasato, are as follows: 1 



"When cultures of this organism are robbed of their 

 bacteria by filtration through porcelain the filtrate contains 

 the soluble poison, and is capable, when injected into animals, 

 of causing tetanus. 



"Inoculations of other animals with bits of the organs 

 of the animal dead from the action of the tetanus toxin 

 produce no result; but similar inoculations with the blood 

 or with the serous exudate from the pleural cavity always 

 result in the appearance of tetanus. The poison is, there- 

 fore, largely present in the circulating fluids. 



" The greatest amount of poison is produced by cultivation 

 in fresh neutral bouillon of a very slightly alkaline reaction. 



"The activity of the poison is destroyed by an exposure 

 of one and one-half hours to 55 C.; of twenty minutes to 

 60 C.; and of five minutes to 65 C. 



"By drying at the temperature of the body under access 

 of air the poison is destroyed; but by drying at the ordinary 



1 Zeitschrfit fur Hygiene, 1891, Bd. x, S. 267. 



