ST 
—— 
————— ee 
46 
carbonic acid from destroyed sugar molecules. This process, which 
in most cases is of but short duration and is terminated by the early 
death of the cells by suffocation, is known under the name of ‘“intra- _- 
molecular respiration.” The recent important observations of Eugen 
Bamberger furnish an interesting chemical analogy to ordinary and 
intramolecular respiration. He found that (@-phenylhydroxylamine 
not only oxidizes itself readily on contact with air and induces oxida- 
tion of other compounds, as indigo-carmine, but can also, in the pres- 
ence of a little alkali and the absence of air, change itself to aniline 
and nitrosobenzene, which represents on the one side a reduction 
and on the other an oxidation, in full analogy to the changes in intra- 
molecular respiration. 
The development of oxygen by the action of catalase upon hydrogen 
peroxid recalls another instance of development of oxygen; it is the 
assimilation of carbon. Here the oxygen developed is generally 
assumed to be derived directly from carbonic acid, as expressed by 
the following equation: 
eee Gees O 
ao Ona coe = Ga 2 
—_—_—— ——————— EE! ee 
Carbonic acid. Formic aldehyde. Molecular oxygen. 
An ingenious hypothesis of Erlenmeyer’ tries, however, to explain 
ethis separation of oxygen by a previous formation of hydrogen per- 
oxid and assumes formic acid to be the first organic product of the 
assimilation process. 
Y OH, AL AOE 
O=€ + | becomes -O=C + HO—OH 
\OH OH \H 
Sea aEEEEEEnERETEIEEEEEE 
Formie acid. Hydrogen peroxid. 
HO—OH 
— 2H,0 + O, 
HO—OH 
Since the formation of formic acid is not very probable, we might 
substitute the following equation which would express an eventually 
direct formation of formic aldehyde, which by condensation may yield 
sugar. 
OH HOH J SEO: 
=(, — becomes O=C 4. 
\OH “HOH STL ER) 
2H,0, = 2H,0 + 0,. 
O 
Pfeffer’ gives the following declaration against the above hypoth- 
esis: ‘‘ Erlenmeyer supposed that formic acid and hydrogen peroxid 
are formed during the assimilation of carbon dioxid—a theory which 
the absence of hydrogen peroxid from assimilating plants conclusively 
negatives.” The undeniable fact that all reagents fail to show the 
‘Berichte der Deutschen Chemischen Gesellschaft, 1877, p. 634. 
? Physiology of Plants, Vol. I, p. 356 (1900. ) 
