40 
color with guaiacum. Hence, according to these authors, the bluing 
of guaiacum by plant extracts and ferments, such as diastase and 
emulsin, is due not to an oxidation of the guaiacum by the oxygen of 
the air, but to a hydrolysis ( Jiydroxylirung ) of the guaiacum by the 
plant extract or ferment. Bertrand ( 51 ), however, is of the opinion 
that the bluing of the guaiacum is due to the combined action of 
oxygen and laccase, and Kastle and Loevenhart ( 244 ) were unable to 
obtain any evidence of the bluing of guaiacum by the freshly abraded 
surface of the raw potato in an atmosphere of hydrogen, carbon diox- 
ide, or nitrogen. On the other hand, in air or oxygen, the freshly 
abraded surface of the potato was always found by these observers 
to develop a blue color instantly on the application of tincture of 
guaiacum. 
OXYGEN-EXCITERS AND OXYGEN-CARRIERS (“ SAUERSTOFFERREGERN ” 
AND “SATJERSTOFFTRAGERN,” Schoenbein ). 
In 1855 Schoenbein ( 378 ) made a study of the spontaneous bluing 
of certain fungi. The results of these interesting observations were 
given to the world in a communication entitled “Leber die selbst 
Blauung einiger Pilze und das Yorkommen von Sauerstofferregern 
und Sauerstofftragern in der Pflanzenwelt," and also in a letter to 
Faraday on “ Ozone and ozonic actions in mushrooms.” The titles 
of these two communications give a good idea of their contents. In 
brief his results were as follows: It had long been recognized that 
certain varieties of the higher fungi, notably the Boletus luridus, have 
the remarkable property of rapidly turning blue when the head or 
stem is broken or bruised in any way. Schoenbein now conceived 
the idea that in such color changes we have to do with phenomena 
similar to the bluing of guaiacum by the fresh tissue of the potato 
and other fresh roots. As a matter of fact he found this species of 
boletus to contain a colorless principle easily soluble in alcohol, and 
exhibiting the closest analogy to guaiacum, in that all oxidizing 
agents which blue a tincture of the latter also blue an alcoholic solu- 
tion of the chromogenic substance of the mushroom, and, further, that 
all deoxidizing agents which discharge the color of guaiacum blue 
also discharge the color of the blued fungus extract. From these 
observations he was led to conclude that the chromogenic principle 
of the fungus, like guaiacum, is capable of combining with ozonized 
o 
oxygen, O, whereas it is not affected by ordinary oxygen (O). 
The fact that the alcoholic solution of this coloring principle of the 
Boletus is not spontaneously colored by atmospheric air, but is col- 
ored by air in the parenclryma of the fungus, led him to suspect that 
there exists in the fungus another substance endowed with the prop- 
erty of exalting the chemical power of ordinary oxygen, thereby caus- 
ing this element in its active form, O, to associate itself with the ’ 
