37 6 PATHOGENIC BACTERIA. 



has suggested that they originate in the intestines of 

 horses and reach the earth from their excrement. 



The relation of the bacillus to manure is very interest- 

 ing, inasmuch as it is most common in manured ground 

 and about stables. It is most probable that the relation 

 is simply dependent upon the fact that in manured ground, 

 where there is much nutriment, the bacilli flourish better 

 than in sterile ground. The occasional occurrence of the 

 bacilli in the excrement of herbivorous animals is to be 

 expected because of the earth they commonly swallow 

 with the food cropped from the ground. 



Verneuil has observed that tetanus rarely occurs at sea 

 except upon cattle transports. Upon such vessels, how- 

 ever, there is likely to be considerable earth and earthy 

 dust from hay, straw, etc., which may carry the bacilli. 



Le Dantec 1 has shown that the tetanus bacillus is a 

 common organism in New Hebrides, where there are no 

 horses. In these islands the natives poison their arrows 

 by dipping them into a clay rich in tetanus bacteria. 



The work of Kitasato has given us a very exact 

 knowledge of the tetanus bacillus and completely estab- 

 lishes its specific nature. 



The organisms generally enter the animal body through 

 a wound caused by some implement which has been in 

 contact with the soil, or enter abrasions from the soil 

 directly. Doubtless many of the wounds are so small 

 that their existence is overlooked, and this, together 

 with the fact that the period of incubation of the dis- 

 ease, especially in man, is of considerable duration (three 

 to ten days), and at times permits the wound to heal before 

 any symptoms of intoxication occur, serves to explain at 

 least some of the reported cases in which no wound is 

 said to have existed. 



It would seem that in some rare cases tetanus can occur 

 without the previous existence of a wound. Such a case 

 has been reported by Kamen, who found that the intes- 

 tine of a person dead of the disease was rich in the 



1 See abstracts in the Centralbl. f. Bakt. u. Parasitenk., ix., 286; xiii., 351. 



