DISINFECTION AND DISINFECTANTS. 219 



or any other. Compared with sulphur dioxide, formal- 

 dehyde has these distinct advantages, namely, it is non- 

 poisonous, is a true deodorant, and does not attack 

 metals, colors, or fabrics. On the other hand, it does 

 not destroy vermin, as does sulphur, a disadvantage 

 that is disappointing in the light of what recent investi- 

 gations have taught us of the highly important part 

 which various insects play in the conveyance of disease. 

 To obtain the best results with both formaldehyde and 

 sulphur requires a full knowledge of the conditions 

 under which they are generated, of the apparatuses used 

 in disinfection, and of such concomitant arrangements 

 of rooms, buildings, conditions of temperature and 

 moisture, etc., as are necessary. It is not the intent of 

 this chapter, however, to enter into the subject of 

 disinfection so extensively as such a description would 

 entail. 



Liquid disinfectants are unequivocally 

 Chemical superior to gaseous ones if direct contact 



DiSINFEC- , , . . . . . c ^-i 



by washmg, immersion, or mixing, 01 the 



TANTS r . . 1 



(liquid) disinfectant and infectious matter can be 

 accomplished. Gases cannot be depended 

 on for more than surface disinfection, a fact which 

 restricts their use to the inaccessible parts of rooms, 

 buildings, ships, etc., and to works of art, e.g., paintings, 

 and fine fabrics. 



The resistance of infectious agents to chemical dis- 

 infectants is subject to the same variations as their 



