HAMILTON SCIENTIFIC ASSOCIATION 65 



How the Germ Accomplishes its Destructive Work^ 



PART II. 



The tubercle bacillus of Koch may, without reasonable 

 doubt, be now accepted as the causa causans of tuberculosis. 



A mistake that must be guarded against, however, is 

 that because a tubercle bacillus comes near or even in contact 

 with the human body an attack of tuberculosis necessarily 

 results. It is not enough that the bacillus find its way to a 

 free surface, but must enter into the tissues of the body 

 before it can do harm. Furthermore, it is very probable that 

 in order to accomplish any dire results such tissues must be 

 damaged or weakened in some way, and a special mode of 

 entrance for the bacillus thus prepared. You know that 

 numbers of medical men are at work every day in our large 

 hospitals specially investigating the causes of death on the 

 post mortem table, and making note of the after death 

 appearances of those tissues which have been invaded by the 

 tubercle bacillus during life. In the course of such invest- 

 igation many of the bacilli must necessarily come into contact 

 with the hands of the pathologist. Many are doubtless 

 swallowed, and many inhaled, and make their way to the 

 respiratory tact. 



Nurses in attendance on those in the last stages of the 

 disease must also come in contact with considerable numbers 

 of these minute micro organisms, and yet in only an 

 infinitesiniidly small number of cases do we find any untoward 

 results, neither so long as these persons are careful to protect 

 themselves — in the case of the pathologist from cuts on the 

 hands, and in the case of both nurse and pathologist from 

 being run down in any way or from congestions and catarrhs of 

 the respirator}' or alimentary tracts — need any be expected. 



In other words, unless the soil is prepared, there can be 

 no reaction between the tissues and the bacillus which can 

 end in the latter getting a foothold in the former. 



