EFFECT OF ANTISEPTICS AND DISINFECTANTS ON BACTERIA. 31 



cannot be artificially cultivated, or the disease is not reproduced by 

 inoculation, so that there is no means of testing whether the agents 

 have had any efEect. One can, therefore, only draw general 

 •conclusions by selecting some well-known pathogenic and non- 

 pathogenic micro-organisms, and considering the influence of 

 chemicals, of hot air and of steam upon them, as representing the 

 ■effect upon the various contagia of disease and the causes of 

 putrefaction. 



Such knowledge must necessarily prove of the greatest im- 

 portance : to the sanitarian, who is concerned in preventing the 

 spreading of disease and in the disposal of putrefactive matter ; to 

 the surgeon, who is anxious to exclude micro-organisms during 

 surgical operations, and to arrest the development of bacteria which 

 have already gained an entrance in wounds ; to the physician, in 

 the treatment of micro-parasitic diseases. 



The sanitarian and the surgeon must profit directly by such 

 experiments, for in the disinfection of clothes and the sick-room by 

 the one, and in the application of antiseptic dressings and lotions 

 by the other, the micro-organisms are encountered, as in the experi- 

 ments, outside the living body. 



The physician, on the other hand, is principally concerned in 

 dealing with micro- parasites when circulating in the blood, or 

 carrying on their destructive processes in the internal tissues. So 

 far as our knowledge at present goes, the physician can avail him- 

 self but httle of the effect of the direct application of the substances 

 which have been found to retard or destroy the growth of the 

 organisms in artificial cultivations, for the concentrated form in 

 which they would have to be administered would prove as deleteri- 

 ous or as fatal to the host as to the parasites. Thus Koch has 

 stated that to check the growth of the anthrax bacillus in man it 

 would be necessary that there should be twelve grammes of iodine 

 constantly in circulation, and that the dose of quinine necessary 

 to destroy the spirilla of relapsing fever would be from twelve to 

 sixteen grammes. The retarding iniluence, however, of certain 

 iiubstances when diluted, and the fact that disinfectants are some- 

 times equally efiicacious in a diluted form when their application is 

 prolonged, seem to indicate measures which may be adopted, in some 

 cases, with chances of success, such, as the inhalation of antiseptic 

 vapours in phthisis. For the most part the physician must look 

 rather to combating the effects of micro-organisms by restoring to 

 its normal standard the lowered vitality which enabled the bacteria 

 to get a footing. 



