52 DESTRUCTION OF BACTERIA BY CHEMICALS 



tected from heat and light, since these factors destroy its 

 power. Skin surfaces must be protected by vaseline, for the 

 solution is very irritating. 



Chloramin-T is another chemical dependent upon chlorin 

 for its action, but is more stable, less toxic, and irritating 

 than Dakin's solution, so that it may be used in stronger 

 percentage (2 per cent.)- It is applied directly to wounds or 

 even to mucous membranes. 



Dichloramin-T is a third chlorin antiseptic. It is not 

 stable and must be suspended and dissolved in an oily 

 menstruum previously saturated with chlorin; chlorinated 

 eucalyptol or paraffin oil (a suitable form being called 

 chlorcosane) are used for this purpose. This substance is 

 used for highly infected wounds or for the nasal cavity by 

 application on gauze or by spraying. It is not very irritating 

 to the skin. 



Carbolic Acid or Phenol. This is a crystalline solid which 

 softens when exposed to the air. It is soluble in 15 parts of 

 water. It must be thoroughly mixed with material to be 

 disinfected. It is not destructive to fabrics or colors. It 

 acts best at about the body temperature. It is not much 

 affected by the presence of organic substances. A 5 per cent, 

 solution kills spores in a few hours, and 1 to 1000 inhibits the 

 growth of all bacteria and may be considered as an antiseptic; 

 3 per cent, solutions kill the pus cocci in one minute. 



Cresols. These are thick, sticky, brown fluids related to 

 carbolic acid. They make a milky emulsion with water. The 

 best-known ones are tricresol, creolin, and lysol. The two 

 latter are probably the best, as they mix with water fairly 

 well. All these substances in 5 per cent, emulsion kill the 

 ordinary bacteria within three minutes and the spore-formers 

 within an hour. 



Other Disinfectants. Ordinary alcohol kills vegetative 

 forms in a few hours. A 70 per cent, alcohol is perhaps the 

 most potent. It has lately been shown that for surface 

 disinfection no method is superior to 10 per cent, iodin in 



