344 PHARMACEUTICAL BACTERIOLOGY 



building to be disinfected, the sulphur dioxide generated and conducted 

 into the room, hall, cellar, or area way to be disinfected, by means of tubing. 

 This is the safest and most satisfactory way. If such apparatus is not 

 available, the flower of sulphur, sulphur candles, or liquefied sulphur dioxide 

 may be used (15 ounces to each 1000 cubic feet of space). Street cars, 

 railway cars, large public conveyances generally, may be disinfected much 

 like rooms, after being well sealed. A safe rule is to use double quantities 

 of the disinfectant for public conveyances, as compared with a sick 

 room, because of the fact that it is diflScult to seal such public con- 

 veyances well. After the disinfectant has acted for a sufficient length 

 of time (twelve to twenty-four hours), the place is opened, aired and then 

 all of the wood work (of furnishings as well as the floor, walls and ceiling) 

 is either washed or sprayed with a i-iooo bichloride of mercury solution 

 or a 3-5 per cent, formahn solution. 



In such communicable diseases as have no animal carriers (other than 

 the patient himself) or where for obvious reasons such carriers are not 

 present, formalin wiU always be the preferred disinfectant, whether for 

 private or pubUc disinfection, bearing in mind that heat and moisture 

 are necessary adjuncts to its use. Formaldehyde is not effective in a dry, 

 cold atmosphere because under those conditions the formahn is converted 

 into solid polymerized paraformaldehyde, "which as such, is inert. 



PubHc or private disinfection by means of formalin may be carried 

 out as follows, the method selected depending upon time, place and 

 opportunity. 



a. Wet Blanket Method. — Immerse blankets or sheets in the formalin 

 solution and suspend them about the room to be disinfected. The room 

 may first be sprayed with a hot 4 per cent, solution of formalin which 

 furnishes warmth and moisture. The operator must work rapidly 

 as formalin is very irritating to eyes and respiratory tract. 



b. Methyl Alcohol Lamps. — Formalin may be generated in the space to 

 be disinfected by oxidizing the methyl alcohol and converting it into for- 

 maldehyde. Lamps of special construction are necessary. The vapor of 

 methyl alcohol is passed over a highly heated plate whereupon it is oxi- 

 dized into formaldehyde (CHaOH-|-0 = HCHO-i-H20) with UberatJon 

 of water. This method of disinfection is now rarely employed. 



c. Sanitary Construction Company's Lamp. — ^The mechanism consists of 

 a tank to hold the formalir, connected with a spiral tube through 

 which the solution is slowly passed through a flame. The heat vaporizes 

 the formahn which is then conducted into the room (through the key hole) 

 by means of suitable tubing. This apparatus is much used by health 

 officers. 



d. The Shering Lamp. — These small compact and most convenient 



