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 Fermalin to which Glycerin has been Added. 
A very convenient apparatus of somewhat greater cost 
than that of Schering’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 
in 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. 
Asa 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 
