LIME WASH AS A DISINFECTANT.

Wairarapa Age, Volume XXXI, Issue 9039, 24 January 1908, Page 7

LIME WASH AS A DISINFECTANT.

Writes a correspondent of the J 'Farmers' Union Advocate": — '•'From almost time immemorial, lime wash lias been considered by the farming community a highly satisfactory disinfectant .ftr loose boxes, icowsheds, stables, etc., although .doubts have been cast upon its effi- ■ J&acy from time to time, and many authorities, including.our own Chief Veterinarian, have usually urged the .addition of a large percentage of ■crude carbolic acid or other disinfectant of a chemical nature, holding that the chief value of the lime wash Jay in the fact .that the person applying it and the person paying for the disinfecting, could both see whether the work had been thoroughly accomplished. Recently during a series of experiments on the values of various disinfectants, conducted by Dr Mcßride, of the Bureau of Animal Industry, Washington, U.S.A., the rather peculiar fact had been brought to light that not only is limewash a poor disinfectant but that carrbolic acid itself when .-nixed iAvitb limevvash, loses to some extent '*its germ killing efficiency. The regulations of the Department of Agriculture recommend for the disinfection of trucks, pens, eel., the'follows ing mixture Lime, carbolic acid £lb # water 1 gallon; or, in other words, 2*| per cent, of carbolic acid added to "the lime wash as ordinarily used„ and this led to its value being put to experimental test; Dr McBride's experiments demonstrate a percentage of carbolic acid, which kills" such a microbe as the staphy- j lococeus pyogenes (one of the pus»producing germs) when mixed with ordinary-water in minutes, failed to do so in twice the time when mixed, with lime wash. Similarly i with the .baccilus of swine fever, | which, though killed in less ' 2i minutes with one part of carbolic iUi 125 of water, survived over double dte time when treated with the sair.e ' percentage of carbolic acid in lime ■ wash. The reason of all this is that j a part of the carbolic acid combines 1 with the lime, forming carbolate of ! calcium, which has a weaker disin- j fecting power than the acid, though j of course- much stronger than the ,i lima alona. These experiments show that not only does lime rpquire the addition of a chemical disinfectant, but that the solution requires to be stronger than if water alone be used, at all events with-an acid disinfectant like carbolic."