MINERAL ANTISEPTICS. 107 



unaltered, and may, when cooled, be added to the cold sterile 

 bouillon. 



Under particularly favourable circumstances, exposure to a 

 temperature much below 100 C. can bring about either the 

 complete mortification of the germs present in a solution, or else 

 render them so debilitated that their further development is 

 prevented, so that the liquid will remain for a long time (months 

 and years) without alteration. This result is attainable when the 

 influence of warmth is seconded by suitable antiseptics, substances 

 which we must first consider before noticing the combined process 

 of sterilisation to which we are gradually leading up. 



79. Mineral Antiseptics. 



The substances exerting a toxic action on micro-organisms are 

 still often divided into two groups : those serving to annihilate 

 the pathogenic bacteria being termed disinfectants; whilst the 

 substances capable of retarding fermentation and putrefaction are 

 denominated antiseptics. There are, however, no good grounds for 

 this distinction, since, as we know, there are bacteria capable of 

 originating both disease and fermentation. 



Very exhaustive researches on the efficacy of the various anti- 

 septics are available. Those of R. KOCH (I.) were undertaken in 

 the interest of medical hygiene. As in the case of other agencies 

 inimical to bacteria, so is it in the case of toxic substances : the 

 destruction of the life of vegetative forms of growth is relatively 

 the easiest to effect ; stronger means being necessary to prevent 

 the germination of the endospores, and the most powerful in- 

 fluences of all to kill these latter. 



The strongest antiseptic is corrosive sublimate or mercuric 

 chloride, HgCl 2 ; but, unfortunately, this substance cannot, for 

 hygienic reasons, be employed in the fermentation industry. In 

 the laboratory, however, the fermentation physiologist always keeps 

 a stock of this reagent for disinfecting (inter alia) the bell glasses 

 used for storing fresh plate cultures. A sufficient quantity is also 

 put in vessels containing cultures that are no longer needed, but 

 which should not be placed in the hands of the cleaner until they 

 have been killed. Again, in the laboratory of the chemist in 

 large works a solution of sublimate should always be kept, along 

 with materials for bandages, as being the first remedy to apply 

 when the workmen are injured or wounded. In washing wounds 

 with this solution, one should always be mindful of the fact that 

 the first treatment has a preponderating influence in the restora- 

 tion of health. The strength of solution employed, both in the 

 laboratory and for this Samaritan service, is one gram of HgCl 2 

 per litre of distilled water. Calcareous well-water must not be 

 used, and the author would recommend any chemist who cannot 

 afford to purchase distilled water to prepare his stock of sublimate 



