184 BACTERIOLOGY. 
chamber should be washed out from time to time with 
hot water, to remove any deposit there may be. 
From Trioxymethylene by Schering’s System. This sys- 
tem consists in heating the solid polymer of formalde- 
hyde (trioxymethylene) in a lamp specially constructed 
for the purpose by the Chemische Fabrik auf Actien, 
in Berlin. The trioxymethylene is used in the form of 
compressed tablets or pastilles, as being more convenient 
for use. Each pastille contains the equivalent of 100 
per cent. of formaldehyde gas, according to the manu- 
facturers, and weighs | gramme. 
The mode of using the apparatus is very simple: 
The disinfector is placed upon a sheet of iron on the 
floor of the room to be disinfected. From 100 to 250 
pastilles can be evaporated at a time in the apparatus. 
For the production of greater quantities of formalde- 
hyde vapor several of these outfits may be used 
together. The lamp is filled with ordifary or wood 
alcohol, about twice as many cubic centimetres of the 
alcohol being employed as there are pastilles to be evap- 
orated. The wicks should project but little above the 
necks of the burners, or the apparatus may get too hot 
and ignite the pastilles. The vessel is charged with 
formalin pastilles and the disinfector placed over the 
lighted spirit lamp. The lamp is then allowed to burn 
out in the closed room. One hundred pastilles are con- 
sidered to be sufficient for the disinfection of 1000 cubic 
feet of space. Lately, a small steam boiler has been 
added to the apparatus, for the purpose of furnishing 
sufficient moisture with the gas. The results obtained 
by us in superficial disinfection, when from 150 to 200 
pastilles have been used to each 1000 cubic feet, have 
been good. The great advantage of the method is in the 
