40 DISINFECTANT 



This evolution does not last long, but long enough to niako them useless as disinfect- 

 ants when used so strong. Vinegar is the best of the purely acid disinfectants ; wood 

 vinegar the best of the vinegars, because it unites to the acidity a little creosote. 

 Vinegar is a very old and well-established agent ; it has been used in the case of the 

 plague and various pestilences from time immemorial. It is used to preserve eatables 

 of various kinds. For fumigation no acid vapour used is pleasant except vinegar, and 

 in cases where the impurity is not of the most violent kind, it may be used with great 

 advantage. Even this, however, acts on some bright surfaces, a disadvantage attending 

 most fumigations. 



Sulphurous acid, or the fumes of burning sulphur, may be treated under this head, 

 although in reality it does not act as a mere acid combining with a base and doing no 

 more. It certainly unites with bases so that it has the advantage of an acid, but it 

 also decomposes by precipitating its sulphur, as when it meets sulphuretted hydrogen. 

 It therefore acts as an oxidiser in some cases, but ifc is generally believed, from its 

 desire to obtain oxygen, that it acts by being oxidised, thus showing the peculiar 

 characteristics of a deoxidiser. We can certainly believe that bodies may be disin- 

 fected both by oxidation and deoxidation. The solutions of sulphurous acid act as a 

 restraint on oxidation, and preserve like vinegar. Its compounds with bases, such 

 as its salts of soda, potash, &c., preserve also like vinegar, saltpetre, &c. ; probably 

 from their affinity for oxygen, taking what comes into the liquid before the organic 

 matter can obtain it. But it is not probable that this rivalry exists to a great extent ; 

 the presence of the sulphurous acid in all probability puts some of the particles of oxy- 

 gen in the organic matter in a state of tension or inclination to combine with it, so 

 that the tension of the particles which are inclined to combine with the oxygen of the 

 air is removed. 



Sulphur fumes are amongst the most ancient disinfectants held sacred in early times 

 from their wonderful efficacy, and still surpassed by none. With sulphur the shepherd 

 purified or disinfected his flocks, and with sulphur Ulysses disinfected the suitors which 

 he had slain in his house. No acid fumigation is less injurious generally, vinegar ex- 

 cepted, to the lungs or furniture, and its great efficiency marks it out as the most desirable, 

 although much laid aside in modern times. The amount arising from burning coal 

 must have a great effect in disinfecting the putrid air of our streets, and rendering 

 coal-burning towns in some respects less unpleasant ; this is one of the advantages 

 which that substance brings along with it, besides, it must be confessed, greater evils. 

 It is curious that this compound of sulphur should be one of the most efficient agents 

 in destroying sulphuretted hydrogen, another compound of sulphur. Sulphurous acid 

 prevents decomposition, and also preserves the valuable principle of a manure, so that 

 it belongs partly to the class of disinfectants, and partly to antiseptics. 



The peculiar actions of sulphites and carbolic acid have been united in that called 

 ' Me Bengali's Disinfecting Powder ' ; where it is desirable not to use liquids, these two 

 have been united into a powder, which assists also in removing moisture, as water is 

 often a great cause of discomfort and disease in stables and cowhouses. When they 

 are used in this manner the acids are united with lime and magnesia. The cattle are, 

 it is said, freed from a great amount of illness, not only because the air of the stable 

 is purified, but that it is dried at the same time. It does not seem well to use excess of 

 water in our climate, and it is then that a disinfecting powder becomes so valuable, and 

 where our towns are so badly supplied with water-closets that disinfectants are wanted 

 for the middens. 



It has been proposed to disinfect sewers, as well as sewage, by the same substances ; 

 not, however, in the state of a powder. The acids are applied to the sewage water 

 in the sewers themselves, and so cause the impure water to pass disinfected tlimuirh 

 the town ; by this means the towns and sewers are to be purified together. I 

 the above-mentioned powder, there are Calvert's disinfecting powder containing car- 

 bolic acid, and Mudio's disinfecting powder with metallic salts. 



Lime is used for precipitating sewage water, and acts as a disinfectant as far as the 

 removal of the precipitate extends, and also by absorbing sulphuretted hydrogen, 

 which, however, it allows again to pass off gradually. The other substances pr 

 for sewers have chiefly relation to the precipitation, and do not so readily come in:der 

 this article. Charcoal has been mentioned. Alum has been proposed, and it certainly 

 does act as a disinfectant and precipitant. None of these substances have l*een tried 

 on a great scale, excepting lime, and carbolic acid or tar products, the first at Leicester, 

 the second at Carlisle. 



Absence of air is an antiseptic of great value. The process of prosorving meat, 

 called Appert's process, is by putting it in tin vessels with water, boiling off . 

 deal of eteam, to drive out the air, and then closing the aperture with sul<!er. 

 Schroeder and De Dusch prevented putrefaction for months by allowing no air to 

 approach the meat without passing through cotton ; BO also veils are found to be a 



