105 



Naturally, the collection and recording of all these data per- 

 taining to over a hundred separate plants and plant parts was no 

 mean task, and to facilitate the process as much as possible we 

 had mimeographed sheets prepared with appropriate columns so 

 that the labor of recording and preserving many hundreds of 

 observations was reduced to a minimum. 



As reagents for the oxidases, we used ordinary guaiac tincture, 

 also tincture of guaiacum which had been boiled with bone-black 

 to remove peroxides,^- a-naphthol, the hydrochloride of para- 

 phenylene-diamine, phenolphthalin, the indo-phenol reagent and 

 phenol. Both the ordinary and purified guaiac tinctures were 

 2 per cent, solutions of gum guaiacum in absolute alcohol. These 

 tinctures give a blue color when oxidized. 



The a-naphthol reagent had a concentration of i per cent, of 

 the substance in a 50 per cent, aqueous solution of alcohol. It 

 gives a lavender color when oxidized. 



The para-phenylene-diamine solution contained i per cent, 

 of the hydrochloride in distilled water. This reagent yields a 

 greenish color when oxidized. 



The phenolphthalin reagent was made according to Kastle's 

 method.^* We treated a pinch of phenolphthalin with i c.c. 

 of N/io NaOH solution, dissolved as much of it as possible, 

 then added 25 c.c. of water, filtered and made up to 100 c.c. 

 We used 5 c.c. of this solution plus 10 c.c. of the extract to be 

 tested for the oxidase, let the mixture stand fifteen minutes, then 

 made it alkaline with N/20 NaOH solution, when the mixture, 

 in the presence of oxidases, acquired a pink or red color due to 

 the phenolphthalein resulting from the oxidation of the colorless 

 phenolphthalin. 



The indo-phenol reagent was applied by adding two or three 

 drops of a I per cent, solution of a-naphthol in 50 per cent, 

 alcohol and an equal amount of a i per cent, aqueous solution 

 of para-phenylene-diamine hydrochloride to the extract to be 

 tested, then making the mixture slightly alkaline with sodium 



82 Moore and Whitley. The Properties and Classification of the Oxidizing En- 

 zymes, etc. Biochem. Jour. 4: 136. 1909. 



«3Kastle, Chemical Tests for Blood. Bull. 51, Hyg. Lab'y. U. S. Pub. Health 

 and Marine Hospital Service, Washington, 1909, p. 25 ff. 



