DISINFECTANT 



47 



a solution of caustic soda, whilo oil of tar is nearly insoluble ; but if the amount of 

 carbolic acid be increased some remains undissolved. 



' To apply the tests : 1. Put a toaspoonful of the carbolic acid in a bottle, pour on 

 it half a pint of warm water, and shake the bottle at intervals for half an hour, when 

 the amount of oily residue will show the impurity. Or, dissolve one part of caustic 

 soda in ten parts of warm water, and shake it up with five parts of the carbolic acid. 

 As before, the residue will indicate the amount of impurity. 



' These tests will show whether tar oils have been used as adulterants ; but to ascer- 

 tain whether the liquid consists of a mere solution of carbolic acid in water or alkali, 

 or whether it contains sulpho-carbolic or sulpho-cresylic acids, another test must bo 



Tenth Day. Temperature 80-86 F. 



