500 BACTEEIA AND SANITATION 



and to get into the blood is a difficult matter for bacteria, 

 since the skin is of such structm-e as to prevent passage of 

 the .germs. In the case of woimds or breaks in the skin, 

 these serve as excellent passages into the blood for bacteria. 

 The entrance of bacteria into the body is spoken of as in- 

 fection, and the part where they enter is said to be infected. 

 It becomes, therefore, extremely important that a wound 

 which is liealing be kept free from these dangerous germs. 

 Medical men have discovered certain chemicals which 

 when applied to wounds do not prevent healing but at the 

 same time do prevent the development of bacteria. Such 

 substances are called antiseptics. AH wounds should be 

 first washed as clean as possilDle with warm water and 

 then bandaged with one of these antiseptics. In this way 

 antiseptics such as 0.1 per cent and 0.05 per cent solutions 

 of carbolic acid and corrosive sublimate, may prevent such 

 serious complications as tetanus or lockjaw, and blood- 

 poisoning. It should be borne in mind that small wounds 

 are quite as dangerous as large ones in this respect and 

 should be treated as carefully. 



In operations requiring the use of instruments everything 

 used must be freed from bacteria. The process usu- 

 ally consists in treating the instruments and clothing worn 

 as well as the hands to the action of various chemicals or 

 antiseptics. Thus, the instruments are frequently soaked 

 in solutions of carbolic acid or corrosive subUmate or are 

 submitted to the action of hot steam. Materials made 

 bacteria free in this manner are said to be sterilized or dis- 

 infected. Both terms indicate the same result, but the 

 word disinfected is more frequently applied to the result of 

 chemical treatment, while sterilizing more often refers to 

 the action of heat. In removing a splinter with a needle 



