56 INFECTION AND IMMUNITY 



and that it has no injurious action upon furs, leather, 

 copper, brass, nickel, zinc, polished steel or gilt work. 

 Iron and unpolished steel are attacked by the gas. 



As is the case with sulphur dioxid the germicidal 

 power of formaldehyd is increased by the presence 

 of moisture. 



Other volatile and gaseous disinfectants have been 

 used, but from a practical point of view those men- 

 tioned are the best. Chlorin is a powerful germi- 

 cide in the presence of moisture, but its irritant and 

 corrosive properties interfere with its usefulness as a 

 disinfecting agent. 



