8 The Examination of Waters. 



suggested so to purify water as to guarantee its freedom 

 from these germs of disease." And these authorities believe 

 that " if a spoonful of unhealthy sewage is put into the 

 Thames at Oxford it may poison some persons in London/' 

 In a recent article in the Argus I noticed a statement that 

 during the epidemic of cholera in Italy none of the people 

 employed in the manufacture of borax, or in connection with 

 the works, were attacked by the disease. The claims of 

 borax as a disinfectant and preservative for food have been 

 advanced a great many times of late years, but without 

 much success. But seeing the statement referred to, I added 

 a boiled solution of borax to some freshly filtered water, 

 together with sterilised ammonium tartarate and sodium 

 phosphate, and though the bottle has stood in the laboratory 

 for 30 days there are no bacteria yet to be found in it. The 

 same water, treated in the same way, but without borax, 

 becomes cloudy with bacteria in two or three clays ; and in 

 the same water unfiltered, in which there are developed 

 bacteria, the borax has no effect; the increase in number 

 goes on just as rapidly with as without it. This explains 

 some of the contradictory results obtained with borax and 

 boracic acid. It has some effect on the germs, but not on 

 the developed bacteria. If the statement from Italy is 

 true, and I see no reason to doubt it, the explanation seems 

 to be that all the water about the borax works contains this 

 salt, and the workmen are continually taking it into their 

 systems, and that the germs became passive, or died in the 

 borax water. On fully active bacteria I have tried the 

 action of several so-called disinfectants, and find that dilute 

 solutions have little or no effect. They swim about in a 

 distinctly purple solution of permanganate of potash, and 

 seem to reject it ; and 1 per cent, carbolic acid takes a long 

 time to kill them. Lime water kills them, but not if too 

 dilute ; but lime-like borax seems to prevent the growth of 

 the germs, and a mere trace of benzine destroys both germ 

 and bacteria, and probably most hydro- carbons do the same ; 

 and we may yet have to return to the work of the late Dr. 

 Day, of Geelong, and study the action of hydro-carbons, and 

 the formation of peroxide of hydrogen, and there find our 

 best disinfectant. These crude experiments, with which I 

 do not offer any figures, as I do not yet know the minimum 

 quantity of disinfectant required, suggest many others. 

 Though it is possible that some means may be found to 

 prevent infection by killing germs in poisonous waters, I 



