342 BOTANICAL GAZETTE . [OCTOBER 
The main evidence for the theory is the likeness between the oxidations pro-— 
duced in the animal body and those produced in vitro by hydrogen peroxide. 
It is held that hydrogen peroxide cannot be the effective peroxide in the 
organism because of the general presence of catalase in active tissues. Organic 
peroxides are probably the effective agents. The following are listed as 
peroxide-forming substances: elementary metals and non-metals (hydrogen, 
phosphorus, zinc, etc.), hydrocarbons, terpenes, alcohols, aldehydes, acids, 
carbohydrates, ethers, phenols, and aromatic bases and alkaloids. 
The following are a few of the reactions mentioned that show the resem- 
blance between the oxidations in the animal body and those carried on in vitro 
by hydrogen peroxide. The normal fatty acids in the body undergo oxidations 
in the B position, butyric acid yielding acetoacetic acid. Hydrogen peroxide 
alone of all the various chemical oxidizing agents brings about precisely the 
same reaction. 
CH;CH.CH,COOH ~ CH,COCH.COOH 
butyric acid acetoacetic acid 
Glucose may be oxidized to glucoronic acid in the body, while hydrogen 
peroxide is the only reagent capable of effecting this change outside the body. 
Benzene is oxidized in the body to phenol, catechol, and quinol, and precisely 
the same reaction is brought about by hydrogen peroxide, but by scarcely any 
other reagent. Among the dibasic acids, oxalic acid is oxidized readily by 
most laboratory reagents, but malonic, succinic, and glutaric less readily. In 
the body oxalic acid is oxidized with great difficulty, but the other three men- 
tioned above very easily. The’salts of these dibasic acids act similarly toward 
hydrogen peroxide. The saturated and unsaturated fatty acids are about 
equally readily oxidized in the body and by hydrogen peroxide. To most 
laboratory reagents the saturated acids are far more resistant than the unsatu- 
rated. It seems probable from this that botanists? are wrong in assuming the 
greater ease of oxidation of unsaturated acids in the plant. 
We need not enter into our knowledge of the details in the course of the 
complete oxidation of any of the various substances yielding energy. It will 
suffice to say that many steps are not yet known and others are in dispute, 
? Bor. Gaz. §4:543-545. 1912. 

