30 



The Philippine Journal of Science 



sumption decreases. The results are also shown graphically in 

 fig. 5. 



The scope of the work does not warrant a detailed study of 

 this reaction :! at this time. The results are presented because 

 they are sufficiently definite to show the disturbing factors that 

 may be present in the tests of the chlorine consumption of a 

 water or sewage. Probably different chlorine-substitution pro- 

 ducts are formed with different concentrations of urea, some 

 of which react immediately with potassium iodide, liberating 

 iodine, some reacting slowly or not at all, so that the amount of 



Urea additions in milligrams. 





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available chlorine left in solution may not be a true measure of 

 the reaction. Since these products may have even stronger 

 disinfecting action (21) than chloride of lime, the determination 

 of chlorine consumed is not necessarily an index of the quantity 

 of hypochlorite required for disinfection. 



According to Hairi,(8) the liquids in which the disinfecting 

 action of chlorine is greatly retarded show a strong chlorine- 

 consuming power. In a solution of peptone, for example, neither 

 the chlorine consumption nor the inhibition of germicidal action 

 varies in the same manner as the concentration. 



'After this work had been completed, I found that Dakin (3) had 

 reported a similar anomalous reaction between hypochlorous acid and 

 sheep serum. 



