TRANSACTIONS OF THE SECTIONS. 35 



It is higUy impoi-tant that the best plan of disinfection adapted to tlie present, 

 or like emergencies, should be definitely settled by some competent authority, and 

 its adoption then made uniform throughout the country. The various disinfectants 

 ouglit always to supplement each other, so that when the contents of the adjacent 

 sewers blen^ together, the purifying action of the disinfectants used should pervade 

 the mass. 



The word '^ disinfectant," in its ordinary sense, implies a body which wiU destroy 

 an animal poison or virus, in -whatever way it is accomplished ; in a more restricted 

 sense, the term is used to indicate an agent which destroys organic _ or ofl:ensive 

 matter by oxidation or analogous action; whilst under the tenn "antiseptics '' ai'e 

 classed those agents which arrest poisonous action by destroying the tendency to 

 putrefy, and stopping chemical change. 



Oxich'zittf/ disinfectants — those which actually burn up organic matter by means 

 of combined or atmospheric oxygen — are by far the best known and most used ; 

 inasmuch as they appeal directly to popiilar prejudice, by destroying the foul 

 odours which are the usual accompaniments of infection, whilst ^'antiseptics^' have 

 little or no action on these gases. This fallacious mode of estimating their relative 

 value is one which does great injustice to antiseptics. 



In the search for disinfectants suitable to arrest the progi-ess of a zymotic disease, 

 it is necessary to strike otfat once a whole class of valuable agents which will not 

 meet the requrements of the case. It is more than probable that the infectious 

 matter partakes of the physical properties of a vapour or of fine dust ; and it is 

 consequently hopeless to attempt to combat the virus by non-volatile disinfectants. 

 For this reason, charcoal, chloride of zinc, the permanganates, solutions of metallic 

 salts, and other similar substances are of limited use : what is wanted for general 

 purposes, is a liquid and a volatile disinfectant, which, after first acting on infected 

 surfaces, M'ill, by gaseous diflnision, pervade the infected atmosphere, and destroy 

 the floating virus. 



At first sight the action of a powerful oxidizing-disiufectant, like chloride of 

 liine, or Condy's fluid, upon noxious vapours or even septic germs, appears perfect. 

 In presence of an excess of either of these agents, all organic impurity is at once 

 bm-nt up, and reduced to its simplest combinations; and coidd we always rely 

 upon the presence of a suflicient amount of either of these bodies, no other purifiers 

 would be needed. But in practical work, these disinfectants are always very 

 inadequate, except for a short time after their application; at other times, the 

 oxidizing agent has presented to it far more noxious material than it can by any 

 possibilitr^ conquer ; and being governed in its combinations by definite laws of 

 chemical aflinity, the sulphuretted and carburetted hydrogen, the nitrogen- and 

 phosphorus-bases, and other vapours of puti-efaction, will all have to be burnt up 

 before the oxidizing agent can touch the germs of infection ; whilst the continued 

 renewal of the gases of putrefaction will constantly shield the infectious matter 

 from destruction. 



This is the chief objection to disinfectants which act by oxidation. If we ar- 

 range in a series the possible substances which may be present in an infected 

 neighbourhood, and gradually mix with them chlorine or a permanganate, we find 

 that these vapours, which have strong and foetid odom-s, and which we will place 

 at the commencement of the list, are the first to go ; whilst the actual virus of the 

 disease — the organized particles which have little or no odour — are the last to be 

 attacked. It so happens that the stinking gases of decomposition are of compara- 

 tively little danger, whilst the deadly virus-cells of infectious diseases are inap- 

 preciable to the sense of smell. Again, oxidizing disinfectants possess little or no 

 permanent action. What they attack is destroyed perfectly, but what they leave 

 has no special resistance to decomposition conferred upon it. They remove the 

 products of decomposition, but they do not take away the power of subsequent 

 decomposition. Mere deodorization therefore is no protection whatever. 



Oxidizing disinfectants produce their effect by the actual destruction of the in- 

 fecting substance. Antiseptics act by destroying its activity. The former act more 

 energetically upon dead than upon li'^ing organic matter. Antiseptics attack first 

 the opposite end of the list, and commence by destroying -vitality. They exert 

 little or no action on the foul-smelling but comparatively hanuless gases of decom- 



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