9 
flame was then extinguished and the slow oxidation of the alcohol was 
allowed to proceed. Solutions containing' y per cent of the aldehyde 
were thus prepared. 
In 1881 Kabloukotf (5) prepared large amounts of the aldehyde by 
passing mixtures of air and methyl alcohol through a glass tube tilled 
with platinized asbestos and heated in a combustion furnace. 
In 1881 Tollens (6) prepared the aldeh^^de by passing air and the 
vapors of method alcohol, heated to 55° C., over platinum foil, and 
concentrating the distillates by a second distillation. In this manner 
he obtained solutions containing 11.3 per cent of the aldehyde, and by 
drying over sulphuric acid he obtained the pure compound. 
O. Loew (7) in 1886 devised the following method for the prepara- \ 
tion of the aldeh^^de: A current of dry air is drawn as quickly as pos- 
sible through a half -liter flask half filled with methyl alcohol and then 
through a hard glass tube 30 cm. long, containing' a cylinder of coarse 
copper gauze 5 cm. long, and then successively through an emph^ 
flask of 300 to 100 c. c. capacit}^ and two flasks half filled with water. 
The part of the glass tube containing the copper gauze is surrounded 
with brass gauze and gently heated. When the alcohol vapor reaches 
the copper gauze the latter glows more or less according to the rate 
of the current of air passing over it. When the apparatus has once 
gotten in proper working order the process requires no further 
attention beyond keeping up the supply of alcohol, and the apparatus 
may be left running night and day. A 15 per cent to 20 per cent 
solution of formic aldehyde was obtained in this way. Tollens (6) in 
1886 obtained still better results by passing the air through methyl 
alcohol that had been heated to l:5°-50° C. and by substituting for plati- 
num foil a coil of copper gauze, omitting the condenser and maintain- 
ing a constant stream of air. In this way he was able to obtain 30 
per cent to 10 per cent solutions of the aldehyde with ease, and found 
that 30 per cent of the methyl alcohol burned was converted into the 
aldehyde. 
In 1890 W. Eschweiler (8) employed essentially the same method as 
Tollens and Loew. He found that the best yield is obtained by keep- 
ing the copper gauze at such a low red heat that it only could be seen 
to glow in the dark. In the first receiver he obtained a 10 per cent 
solution of formic aldehyde, and the mixed solutions from all the 
receivers were found to contain from IT per cent to 18 per cent of 
formic aldehyde. 
In 1886 Loew and Fischer (9) discovered that formic aldehyde pos- 
sesses powerful antiseptic properties. Since these earlier observations 
the germicidal action of formic aldehyde has been investigated b}" 
Trillat, Buchner, Aronson, Cohn, and others. As the result of these 
studies, formic aldehvde has come to be used on a large scale as a dis- 
infectant and deodorizer, and the commercial methods used in the 
8049— Xo. 39—07 2 
