PRACTICAL I)ISI\n-;cTI<>\ AM) STERILIZATION 129 



fecting chamber, the latter to be provided with a heating and if pos- 

 sible a vacuum apparatus and special apparatus for generating the gas. 

 Where penetration through heavy articles is required the gas should 

 be used in the proportion of not less than the amount derived from thirty 

 ounces of formalin for each 1000 cubic feet, the time of exposure to be 

 not less than eight hours and the temperature of the chamber not below 

 110 F. 



In order to ensure complete sterilization of the articles they should 

 be so placed as to allow of a free circulation of the gas around them 

 that is, in the case of bedding, clothing, etc., these should either be 

 spread out on perforated wire shelves or loosely suspended in the cham- 

 ber. The aid of a partial vacuum facilitates the operation. Upholstered 

 furniture and articles requiring much space should be placed in a large 

 chamber, or, better, in a room which can be heated to the required 

 temperature. 



The most delicate fabrics, furs, leather, and other articles, which 

 are injured by steam, hot air at 230 F., or other disinfectants, are 

 unaffected by formaldehyde. 



3. DISINFECTION OF BOOKS. Books may be satisfactorily disin- 

 fected by means of formaldehyde gas in a special room, or in the ordinary 

 steam chamber, as above described, and under the same condition of 

 volume of gas, temperature, and time of exposure. The books should 

 be arranged to stand as widely open as possible upon perforated wire 

 shelves, set about one or one and a half feet apart in the chamber. A 

 chamber having a capacity of 200 to 250 cubic feet would thus afford 

 accommodation for about one hundred books at a time. 



Books, with the exception of their surfaces, cannot be satisfactorily 

 disinfected by formaldehyde gas in the bookcases of houses and libraries, 

 or anywhere except in special chambers constructed for the purpose, 

 because the conditions required for their thorough disinfection cannot 

 otherwise be complied with. 



The bindings, illustrations, and print of books are in no way affected 

 by the action of formaldehyde gas. 



4. DISINFECTION OF CARRIAGES, ETC. Carriages, ambulances, cars, 

 etc., can easily be disinfected by having built a small, tight building, in 

 which they are enclosed and surrounded with formaldehyde gas. Such 

 a building is used for disinfecting ambulances in New York City. With 

 the apparatus there employed a large amount of formalin is rapidly 

 vaporized, and superficial disinfection is completed in sixty minutes. 



5. ADVANTAGES OF FORMALDEHYDE GAS OVER SULPHUR DIOXIDE 

 FOR DISINFECTION OF DWELLINGS. Formaldehyde gas is superior to 

 sulphur dioxide as a disinfectant for dwellings: first, because it is more 

 efficient in its action; second, because it is less injurious in its effects 

 on household goods; third, because when necessary it can easily be 

 supplied from a generator placed outside of the room and watched by 

 an attendant, thus avoiding in some cases danger of fire. 



Apart from the cost of the apparatus and the greater time involved, 

 formaldehyde gas, generated from commercial formalin, is not much 



9 



