DISINFECTION. 421 



main discharge -conduit at the lower end of the irrigation- 

 field presented a marked alkaline reaction. 



For the disinfection of water-conduits dilute milk of lime, 

 carbolic acid, or a mineral acid, is employed. At Nietleben 

 Koch disinfected the service by means of carbolic acid, per- 

 mitting three per cent, carbolic acid to be driven from the 

 pumping well into all divisions of the service, and to remain 

 in the conduits for twenty-four hours. Then the pipes 

 were irrigated with wholesome water. This procedure is 

 attended with the objection that the water retains for a con- 

 siderable time the taste of carbolic acid. On the other 

 hand, however, it does not carry with it the danger of ob- 

 struction of the conduits that attends the employment of 

 milk of lime. 



DISINFECTION OF URINE. 



The urine is usually disinfected in common with the feces. 

 It is generally not so infective as the stools. If it is to be 

 disinfected alone, this may be accomplished by addition of 

 milk of lime, carbolic acid, or mercuric chlorid. 



DISINFECTION OF SPUTUM. 



The sputum must be received and preserved in a moist 

 condition, preferably in sputum-cups containing a layer of 

 water. So long as the sputum is contained within such 

 cups it is relatively harmless. A greater danger resides in 

 the conversion into dust and into spray of sputum evacu- 

 ated into handkerchiefs, upon floors, etc. On emptying 

 the vessel the sputum must be disinfected. Crude carbolic 

 acid (from 5 to 10 per cent.) or mercuric chlorid (i or 2 : 

 1000) would be suited for this purpose if the disinfectant 

 penetrated the sputum. Generally, however, the albumin 

 on the outer surface of the mass of sputum is coagulated, 

 and the bacilli contained within do not come in contact with 

 the antiseptic at all. For this reason the sputum must at 

 least be thoroughly rubbed up in the disinfecting solution, 

 and remain therein for a long time. Lysol (10 per cent.) 

 and crude solutol (from 5 to 10 per cent.) do not coagulate 

 the sputum, and are therefore better adapted for disinfec- 

 tion. It is further useful to disinfect the sputa by heat. If 



