DESTRUCTION OF BACTERIA BY CHEMICALS. 163 
subject when taken internally. Slater and Rideal? 
report that a 1 per cent. solution has been taken in 
considerable quantity without serious results; and tri- 
oxymethylene has been given in doses up to 90 grains 
as an intestinal antiseptic. The vapors of formalde- 
hyde are extremely irritating to the mucous membrane 
of the eyes, nose, and mouth, causing profuse lachry- 
mation, coryza, and flow of saliva. Aronson reports 
that in many of his experiments rabbits and guinea- 
pigs allowed to remain for twelve and twenty-four 
hours in rooms which were being disinfected with for- 
maldehyde gas were found to be perfectly well when 
the rooms were opened. On autopsy the animals 
showed no injurious effects of the gas. Others have 
noticed that animals, such as dogs and cats, which 
have accidentally been confined for any length of time 
in rooms undergoing formaldehyde disinfection occa- 
sionally died from the effects of the gas. Many 
observers, however, have reported that insects, such as 
roaches, flies, and bedbugs, are not, as a rule, affected. 
The result of these observations would seem to indicate 
that although formaldehyde is comparatively non-toxic 
to the higher forms of animal life, nevertheless a cer- 
tain degree of caution should be observed in the use of 
this agent. 
The results of numerous experiments have shown 
that in the air, 2.5 per cent. by volume of the aqueous 
solution, or 1 per cent. by volume of the gas, are suffi- 
cient to destroy fresh virulent cultures of the common 
pathogenic bacteria in a few minutes. The researches 
of Pottevin and Trillat have shown that the germicidal 
1 Lancet, April 21, 1894. 
