THE DESTRUCTION OF BACTERIA 89 



purpose about three pounds of sulphur should be burned for every 

 thousand cubic feet of space. It should be allowed to act for not less 

 than twenty-four hours. The researches both of Wolffhiigel 1 and of 

 Koch 2 have shown that the gas is not sufficient for the destruction of 

 spores. Park 3 believes that sulphur dioxid used in quantities of four 

 pounds of sulphur to 1,000 cubic feet is of practical value for fumigating 

 purposes in cases of diphtheria and the exanthemata. Sulphur dioxid 

 fumigation is more effective than formaldehyd for the destruction of 

 insects fleas, lice and bedbugs a matter of importance in epidemics 

 of typhus fever, relapsing fever, plague, etc. 



Of all known gaseous disinfectants by far the most reliable is form- 

 aldehyd. In all cases where formaldehyd fumigation is intended, 

 clothing, bed-linen, and fabrics should be spread out, cupboards and 

 drawers freely opened. The cracks of windows and doors should be 

 hermetically sealed with paper strips or by calking with cotton. In all 

 cases moisture should be provided for, either in the generating appa- 

 ratus or by a separate boiler. 



Direct evaporation of formaldehyd from formalin solutions has been 

 the principle underlying most of the methods. If such evaporation is 

 attempted from an open vessel, however, polymerization of formal- 

 dehyd to the solid trioxymethylene occurs. To prevent this, Trillat 4 

 and others have constructed special autoclaves in which 20 per cent of 

 calcium chloride is added to formalin which is then vaporized under 

 pressure. 



The Trillat autoclave, as well as others constructed on the same 

 principle, consists of a strong copper chamber of a capacity of about a 

 gallon, fitted with a cover which can be tightly screwed into place. 

 The cover is perforated by an outlet vent, a pressure gauge, and a 

 thermometer. The whole apparatus is adjusted upon a stand and set 

 over a kerosene lamp. Into the chamber is put about one-half to three- 

 quarters its capacity of 40 per cent formaldehyd (commercial formalin) 

 containing 15-20 per cent calcium chlorid. The solution used should 

 be free from methyl alcohol, since this leads to the formation, with 

 formaldehyd, of methylal, which is absolutely without germicidal 

 action. For a room of about 3,000 cubic feet Trillat advises the con- 



1 Wolffhiigel, Mitt. a. d. kais. Gesundheitsamt, i, 1881. 



2 Koch, Mitt. a. d. kais. Gesundheitsamt, i, 1881. 



3 Park, "Pathogen. Bact.," N. Y., 1908. 



4 Trillat, Compt. rend, de 1'aead. des sc., 1896. 



