torr] SCHREINER & SULLIVAN—ROOTS 281 
alfalfa previously studied by BERTRAND consisted of the neutral 
salts, mainly calcium, of certain polybasic organic acids, among 
which glycollic, mesoxalic, citric, malic, and probably glyoxylic 
acids have been determined. 
Numerous inorganic compounds will change tincture of guaiac 
blue. Among these SCHONBEIN (29) mentions the oxides of the 
noble metals, the so-called superoxides, saltpeter, chromic acid, 
permanganic acid, etc., lead peroxide, bromine, chlorine, etc. 
ALSBERG (30) has shown that many salts have the power to change 
guaiac to a blue oxidation product either directly or with the addi- 
tion of hydrogen peroxide. MARTINAND (31) finds that oxides 
of alkalies and alkaline earths which can form peroxides and per- 
carbonates fix oxygen of the air in an active form, and form bodies 
which give reactions like organic oxidases. Salts of the oxides of 
metals possessing several degrees of oxidation give the oxidase 
reaction in their maximum oxidation. The oxidation was retarded 
by certain salts and especially by traces of sulphuric acid. WOLFF 
(32) found that colloidal ferrocyanide of iron exerted in certain 
oxidations a catalytic effect similar to that of natural peroxidases. 
According to Wotrr and Dr SToECKLIN (33), ferrocyanides and 
sulphocyanates of iron can produce oxidations which can be effected 
by natural peroxidases, each producing specific oxidations not 
characteristic of the other. Dr SToEcKLIN (34) later found that 
tannate of iron in the presence of hydrogen peroxide can bring 
about oxidation of such compounds as generally resist the action 
of any natural peroxidases now known. Among the substances 
were phenols, cresol, thymol, anisol, carvacrol, guaicol, pyrogallol, 
eugenol, isoeugenol, and tyrosine. 
In work with aloin, we found that a solution of ferric chloride 
containing 3 p.p.m. Fe gave good oxidation of aloin. Ferrous 
chloride, even in solutions containing 25 p.p.m. Fe, did not oxidize 
aloin without the addition of hydrogen peroxide. With the addi- 
tion of hydrogen peroxide, 1 p.p.m. Fe as FeSO; strongly oxidized 
the aloin. Other salts which have a direct oxidizing action on 
aloin are manganese dioxide, calcium oxide and carbonate, and 
Magnesium oxide. Aluminum sulphate and chloride in 5 p.p.m. 
solution oxidized the aloin with the addition of hydrogen per- 
