iQoS] SCHREINER ^f REED— TOXIC PLANT CONSTITUENTS 99 



The phenol compounds studied displayed varying degrees of 

 toxicity. In general their toxicity does not appear to depend upon 

 the number of hydroxyl groups they contain. Phenol itself is the 

 most toxic of any of the members of that group which have been 

 reported in this paper. Undue credence, however, must not Ix- given 

 to slight differences in the toxicity of the di- and triatomic phenols, 

 because It is known that they are more or less unstable m solution, 

 and as a result may be converted into more toxic compounds. 



The toxicity of cinnamic acid is not difficult to understand when 

 one notes that it is phcnylacrylic acid. Sodium cinnamate is much 

 less toxic than the corresponding acid, indicating at least that a part, 

 but not all, of the injurious properties of cinnamic acid are due to the 

 amount of carboxyl it contains. True (:oo) reported that of a 

 series of sodium salts of organic acids, sodium cinnamate was the 

 most harmful to lupine seedlings. This observation indicates stiU 

 more strongly that the phenylacr}1ic group is responsible for a con- 

 siderable part of the toxicity exhibited by cinnamates. 



Cumarin is related to cinnamic acid, and it is worthy of note that 



cmnamic 



acid containing dissociable hydrogen. 



Daphnetin is another compound which shows a diminished toxicity 

 accompanying a higher stage of oxidation. It differs from cumarin 

 in having two atoms of phenyl-hydrogen replaced by hydrox>'l, with 

 +i-,n ^„^,,i+ fUof t'Ua ^■^v^r■^t-^■ ic snmpwhat diminished. 



While it would be presumptuous to asseri uwi ull-ii^^ — _~ 

 action always accompanies the introduction of oxygen into organic 

 compounds, it is undoubtedly true that in a number of the cases 

 studied, the more highly oxj-genated compounds are less toxic than 

 those contaming less dx^•gen. ilany of these substances which are 

 ordinarily regarded as by-products in vegetable metabolism are highly 

 toxic to seedlings when present in sufficient quantities. 



It wiU be noted that certain of the compounds studied produced 

 the effect which Le Ren.^ (:02. has termed "chemauxesis 

 or sthnulation, a phenomenon which has been studied carefully by 

 RAuriN C69), RicH-^s ('97, '99\ Ono (:oo), and others. 



, . J ., f +v„ f„T,<x; hp studied that the presem 



