CHANNELS OF INFECTION. 225 



inhaled in the form of spray, indicates that this is not a common 

 mode of infection in the absence of spores. This view receives 

 further support from the experiments of Hildebrandt, who made 

 tracheal fistulae in three rabbits, and, after the wound had entirely 

 healed, injected into the trachea of each a pure culture of the anthrax 

 bacillus, which was proved to be virulent by inoculation in mice or 

 guinea-pigs. All of the animals remained in good health. On the 

 other hand, three rabbits which received in the same way a pure cul- 

 ture of the bacillus of rabbit septicaemia died as a result of general 

 infection. 



That man may be infected with anthrax by way of the respira- 

 tory organs seems to be well established. In England the disease 

 known as "wool-sorter's disease" results from infection in this way 

 among workmen engaged in sorting wool, which is liable to contain 

 the spores of the anthrax bacillus when obtained from the skin of an 

 animal which has fallen a victim to this disease. That infection 

 occurs through the lungs is shown by the fact that these organs are 

 first involved, the disease being, in fact, a pulmonic anthrax. 



While these experiments prove the possibility of infection through 

 the respiratory mucous membrane, other experiments made by Hil- 

 debrandt show that under ordinary circumstances bacteria suspended 

 in the air do not reach the trachea in rabbits, but are deposited upon 

 the mucous membrane of the mouth, nares, and fauces. In healthy 

 rabbits the tracheal mucus was, as a rule, found to be free from bac- 

 teria, while they were very numerous in mucus obtained from the 

 mouth or nares. But when a rabbit was made to inhale for half an 

 hour an atmosphere charged with the spores of Aspergillus f umigatus 

 their presence in the lungs was demonstrated by cultivation, the ani- 

 .mal being killed for the purpose half an hour after the inhalation 

 experiment. 

 15 



