264 MICROBES AND TOXINS 



know that the child is infected by the individuals surrounding 

 it, it is in the family itself and in the home that contagion 

 must be prevented. The disease is kept up and spread by 

 infected members of the family and by servants and also by 

 unhealthy houses, in particular by dark, airless rooms. The 

 cutaneous reaction tells us that of a hundred adults harbouring 

 the tubercle bacillus, only twelve are destined to die of 

 tubercle. It is therefore very evident that many human 

 beings recover from the attack of the bacillus and that man is 

 an animal naturally resistant to tuberculosis ; in most of us a 

 sort of spontaneous vaccination takes place. These facts 

 ought not to be overlooked in the search for a method of 

 treatment or prevention of tubercle. 



