TETANUS 235 



and will not grow on potato. The spores are very resistant 

 to heat and to chemical reagents; in fact, the organism 

 has been obtained in pure culture by heating ordinary 

 garden-earth to 80* C. on two or three successive days, 

 and then preparing agar shake cultures from the earth so 

 treated, in which all bacteria — except possibly a few of the 

 thermophilic organisms — will have been killed by the heat 

 to which they have been exposed. To destroy the vitality 

 of the spores, they must be boiled at least twenty minutes, 

 and may require a still higher temperature. 



Pathogenesis. — Cases of tetanus used to be described as 

 ' traumatic ' and ' idiopathic '; but, viewed in the light of 

 bacterial knowledge, it seems probable that idiopathic cases 

 are merely those in which the traumatic injury was so 

 small as to escape notice. The organism is pathogenic to 

 man, guinea-pigs, mice, and rabbits, while birds are but 

 slightly susceptible. Immunity has been produced in mice, 

 guinea-pigs, and rabbits by inoculation with attenuated 

 cultures. A tetanus antitoxin is now prepared at several 

 bacteriological institutions, and cases of its successful em- 

 ployment are frequently reported in the medical journals. 



Dr. Sidney Martin has recently devoted attention to the 

 isolation of the poisonous bodies produced in acute trau- 

 matic tetanus. He recognised the danger of attempting 

 the extraction of such easily-decomposable bodies as these 

 products may be expected to be by the aid of chemicals, 

 and hence he confined himself to the use of alcohol, ether, 

 and water alone as a means of separating them from the 

 tissues. He worked on materials from seven fatal cases 

 of tetanus, employing the blood and spleen. After having 

 made and purified his extracts, he experimented as to their 

 physiological action on mice and rabbits, and proved that 

 he had succeeded in separating two distinct bodies, one of 

 which produced the fever of tetanus, while the other pro- 



