DISINFECTION AND STERILIZATION. 185 



small cost of the apparatus, $3.00, and the avoidance 

 of the danger of deterioration, which is present to some 

 extent in formalin. Smaller lamps are very useful for 

 the deodorization of rooms. 



From Formalin to which Glycerin has been Added. 

 A very convenient apparatus of somewhat greater cost 

 than that of Sobering' s is prepared by Charles Lentz & 

 Sons, of Philadelphia. To the formalin is added 10 

 per cent, of glycerin, and the mixture is simply boiled 

 iu a suitable copper vessel, the steam and formaldehyde 

 gas passing off by a tube. This is a very serviceable 

 apparatus. When it is attempted to vaporize the for- 

 malin too rapidly part of it passes over in fluid form, 

 and is thus wasted. 



With a slightly greater amount of formalin than that 

 used in the high temperature autoclave and heated tube 

 or chamber methods the results seem to be equally as 

 good. The apparatus is very easy to use, and not liable 

 to get out of order. 



Similar forms of apparatus are also employed, when 

 instead of glycerin the formalin is mixed with an 

 equal quantity of water. The water is for the purpose 

 of giving additional moisture to the air, and, at the 

 same time, like the glycerin, to prevent the change of 

 formaldehyde into inert substances. A still simpler 

 method is to hang sheets in a room and throw on them 

 six to twelve ounces of formalin for each 1000 cubic 

 feet, and leave for six hours. If the room is tightly 

 sealed very fair superficial disinfection will take 

 place. 



As a result of the investigations undertaken in the 

 department of health laboratories on the use of form- 

 aldehyde as a disinfectant, and a consideration of the 



