SOMH: EXPERIMEI^TS WITH DISINFECTANTS 1 5 



In the 3rd set (sash of window) growth was present in the Anthrax 

 and Staphylococcus tubes, while the B. coli and B. typhosus tubes 

 remained sterile. 



Conclusions. — These experiments show that this method of disinfection 

 is quite as efficient as the Alformant lamp, but the results are not 

 so conclusive as those got by Lingner's apparatus. It has distinct 

 advantages in that there is no danger from accidents due to fire, and that 

 it requires no special form of apparatus. 



On the basis of my experiments, the Lingner apparatus is, for 

 ordinary disinfecting work, unquestionably superior to the Alformant 

 lamp and the Permanganate process. 



It ought to be added that, although the Alformant lamp is cheap, 

 costing only a few shillings, the paraform tablets are much more 

 expensive than a corresponding amount of formaldehyde in solution. 



B.— LIQUID DISINFECTION BY FORMALINE AND OTHER 



DISINFECTANTS. 



Formaline is a 40 per cent, solution of formaldehyde in water, and, as 

 met with in commerce, is a liquid of a pale, sea-green tint, with a specific 

 gravity of about 1,070, and an acid reaction which is due to formic 

 and acetic acids. In more concentrated solutions, the formaldehyde 

 tends to pass into the polymeric and comparatively inactive form. This, 

 therefore, is the strongest solution which will remain permanent. When 

 exposed to the air the formaldehyde vapour is gradually dissipated 

 and the solution loses strength. Loew and Fischer, in 1886, were 

 the first to state that formaline possessed powerful antiseptic properties. 

 Trillat showed that the presence of a minute quantity of this substance 

 in urine preserved it from putrefying. Buchner, Aronson, Blum, Cohn, 

 and others, have investigated the disinfectant properties of formaldehyde 

 in solution. All are agreed in attributing to it powerful antiseptic 

 and deodorant properties. Blum pointed out that to kill micro-organisms 

 it requires a somewhat strong solution. Slater and Rideal found that a 

 I per cent, solution of formaldehyde is sufficient to kill Staphylococcus 

 pyogenes aureus in from 50 to 60 minutes, B. typhosus in from 40 



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