262 " SPECIFIC TREATMENT" OF DISEASE 



vations of the master. It is evident that patho- 

 logical observation limited to the naked eye ex- 

 amination of the organs of the dead could throw 

 little or no light upon the processes of disease 

 although they may show us some of the conse- 

 quences. 



Men had long been asking themselves what 

 constitutes disease, relapse, cure and recovery, 

 natural and acquired immunity ; is disease merely 

 due to disordered function or to some outside 

 cause? With the discovery of the microscope, 

 which taught men to look at things more carefully, 

 and the adoption of the experimental method of 

 investigation by many inquirers, the light began 

 to dawn. 



Long experience had demonstrated that certain 

 diseases were communicated from one individual 

 to another and such maladies were classed by them- 

 selves. It is mainly with these that we shall con- 

 cern ourselves, as it is chiefly in relation to infective 

 diseases that progress has been made. It was long 

 suspected by some acute observers that infective 

 diseases were due to the entrance into the body 

 of parasites which multiplied therein and were 

 given off by the sick to their surroundings; an 

 indication of something of the kind being afforded 

 by what had been observed in the case of larger 

 parasites and their effects. 



In the last century, Louis Pasteur, a French 

 chemist, undertook the study of the fermentation 



