﻿REED— OXIDASES 



431 



to have a clear conception of their quantitative as well as of their 

 qualitative meaning. The following experiments present such 

 quantitative values. 



Solutions of a number of the oxidase reagents in most common 

 use were made up in equivalent concentrations, o . 1 M in water (in 

 the case of aloin and alpha napthol in 50 per cent alcohol, as they 

 are only slightly soluble in water). As gum guaiac consists of a 

 number of compounds in unknown proportions, a 2 per cent solu- 

 tion of the resin in 50 per cent alcohol was taken. 



Two beakers, each containing 100 cc. of one of these solutions, 

 were placed in a uniform light in such a position that the colors of 

 the solutions could be accurately compared. A standard potassium 

 permanganate solution 2 was then added to one beaker, in sufficient 

 amount to cause a definite change in color due to oxidation, as 

 compared with the beaker to which no addition was made. 3 



Table I indicates the amount of permanganate required to pro- 

 duce the first perceptible change of color in the several reagents 

 tested. The last column of the table also gives the amount of 

 oxygen used in the oxidation as calculated from the amount of 

 permanganate required. 



amount is added t 

 , the- oxidation. 



