Some Experiments witli Disinfectants. 



The following investigation was undertaken at the suggestion of 

 Professor Hay, in order to obtain, at first hand, reliable information as to 

 the efficiency of certain disinfectants, especially formaldehyde or 

 formaline, for the guidance of the Public Health Department of the city. 

 A trustworthy means of gaseous disinfection has been long sought 

 for by medical officers of health, and it is now the accepted 

 opinion that formaldehyde is the best. The disinfectant properties 

 of formaldehyde have been investigated by numerous experi- 

 menters, but their results have been by no means uniform. While all, or 

 nearly all, agree as to its undoubted value as a surface disinfector, there 

 is a wide variance of opinion as to its penetrating power. It is admitted 

 by all that it is virtually non-poisonous, and does not injure textile 

 fabrics. Kenyon states that he subjected over 225 samples of different 

 textile fabrics, hair, fur, leather, etc., to crucial tests, using solutions of 

 various strengths and a saturated atmosphere of the gas. The results 

 obtained were in every way satisfactory. 



Formaldehyde exists in at least three well-recognised isomeric 

 states : — 



1. Formaldehyde (formic aldehyde), a gas at ordinary temperature, 



colourless and possessing slight odour, but having an extremely 

 irritating effect upon the mucous membranes of the nose and 

 conjunctiva. At a temperature of about 20° C. the gas 

 polymerizes into paraformaldehyde, known commercially as 

 paraform. 



2. Paraform, a white substance, unctuous to the touch, soluble in both 



water and alcohol. It consists chemically of two molecules of 

 formaldehyde. It is this substance which is supposed to 

 (239) 



