year, whereas the alcohol extracts were found to be inactive. A com- 
parison of the different organs showed that they activated oxygen 
toward these reagents with different degrees of intensity. As a rule 
they were found to he energetic oxygen carriers, accomplishing these 
oxidations more rapidly than they were brought about by palladium 
foil or palladium-hydrogen. Finally, these authors called attention 
to the general similarity between the synthesis of indophenol and 
similar dyes with that of bromplienol cystein, which, according to 
Baumann, results from the administration of brom-benzene to dogs. 
They arrived at the conclusion therefore that the cells of animal 
tissues contain substances which have the power of activating molecu- 
lar ox}^gen, whereby it can accomplish the oxidation of substances 
not ordinarily directly oxidizable ( dysoxydabler Stoffe). They pro- 
test, however, against the supposition that the oxidation of all diffi- 
cultly oxidizable substances in the organism depends on the action of 
oxygen-carriers . 
The indophenol oxidase is by no means confined to animal tissues. 
Mention has already been made of the work of Pohl ( 329 ) on this sub- 
ject. This author found that many plant tissues react strongly to the 
Rohmann-Spitzer reagent. Especially is this the case with tannin 
needles. He also pointed out that the reaction is also brought about 
by amygdalin, apparently altogether independently of the action of an 
oxidase. It is possible, of course, that his amygdalin may have been 
contaminated with a vegetable oxidase. Rey-Pailliade ( 342 ) also 
found the indophenol oxidase to be widely distributed among plants, 
and according to this author yeast reacts feebly to the Rohmann- 
Spitzer reagent. Abelous and Biarnes ( 5 ) have determined the oxi- 
dizing power of various tissues from the same and different animal 
species, colorimetrically, by means of the Rohmann-Spitzer reagent. 
According to these authors, the tissues of the frog and rabbit, the latter 
killed by bleeding, stand in the following order with regard to oxi- 
dizing power: 
Frog. 
Rabbit. 
Lung. 
Spleen. 
Liver. 
Lung and thyroid . 
Kidney. 
Liver and kidney. 
Testicle. 
Pancreas and suprarenals. 
Brain. 
Ovary. 
Muscle. 
Brain . 
Muscle. 
It will be observed that there is general agreement between these 
findings and those of the same authors and also of Salkowski with 
regard to the relative oxidizing power of the various animal tissues 
toward salicylic aldehyde (see pp. 97-98). 
One of the most interesting facts revealed by these determinations 
is the slight oxidizing power of muscle and nerve tissue as compared 
with that of other animal tissues, and, as pointed out by Abelous 
