CONTROL 01' BACTERIAL DlSEAfSES 249 



gastric juice of the stomach is strongly germicidal, these behig 

 nattire's provisions for turning tlie food over to the absorj)- 

 tive organs gcn'm-frcc. T'rcaks in the skin and mucous mem 

 branes and the mouth an* the great clianncls ol' niirancc loi- 

 germs, and tlie fact that there arc so many prevental)lc in- 

 fections proves that under modern conditions of lite miture's 

 provisions need constant reenforccmcnt. In normal bicathing 

 throuyh the nostrils the iicrnis arc cau<»'ht before thcv reach 

 the lungs, so that even pulmonary tuberculosis is coming 

 more and more to be considered a moutli infection, reaching 

 the lungs cithci' by \\iiy of inllanicd tonsils or by way of 

 stomach, intestiiu% tlioiacic duct, and circulation. 



When the role of bacteria in causing disease was lirst dis- 

 covered, chemical poisons were sought which might kill the 

 germs without quite killing the patient. Carbolic acid (phe- 

 nol), mercuric chloiidc (corrosive subhmate). and formalin 

 were the germicides first used most extensively, and the gov- 

 ernment standard of efhciency, " the phenol coetficient," is 

 the germ-killing power of phenol. Later came the delicate, 

 specific, exact antitoxins and resistance serums that kill the 

 particular germ and have no poisonous action on the cells 

 of the body. Other mmpoisonous germicides, especially the 

 hypochlorites, from general use in purification of drinking- 

 water and sewage, are being adapted to dairy, home, and 

 personal use. Here oxygen is the active germicide, and tlu' 

 end products of the reaction are harndess calcium chloride 

 in case of hypochlorite ot lime, and, with sodium liypo- 

 chlorite, sodium chloride, oi- common sah.^ 



^ "Three ^^-aiiis df a practically harmless suhstance will kill the myriads 

 of germs in a barrel of water. To do the .same work with the poi.sonous cor- 

 rosive sublimate would recjuire at least one ounce, or of the e(iually poison- 

 ous carbolic acid tive pounds (p. 23). . . . Ilypochlorous acid is one of the 

 most powerful oxidizing- a.uents known to chemists. The 'acid mixture" 

 will, within a miiuite. kill spores which resist 5 per cent .solution of carbolic 

 acid for weeks" (\\ 54). — Ilofjker. CMdniidc of Lime in Sanitation. I'.M.". 



