JANUAEY 27, 1911] 



SCIENCE 



139 



this he introduces into the tissue by means 

 of a capillary tube a solution of sodium 

 acid sulphite and methylparamidometa- 

 cresol. After this injection the plant is 

 exposed to the light for a time, when a 

 section of the leaf is placed in absolute 

 alcohol and subsequently examined under 

 the microscope in the presence of a drop of 

 water. The presence of the aldehyde is 

 shown by the formation of a red color. 

 According to the author, the aldehyde as 

 fast as produced combines with the acid 

 sulphite to form the addition compound 

 which is stable in the absolute alcohol. 

 Upon the addition of a drop of water, 

 however, the aldehyde is liberated and 

 forms a characteristic color with the cresol. 

 "While Usher and Priestley'*^ claim to 

 have definitely proved the presence of for- 

 maldehyde in the dead plant according to 

 the method described above, they merely 

 infer its presence in the living plant. In 

 fact, they assert that it would be useless to 

 look for it in a healthy living plant because 

 of the rapidity with which it would be 

 transformed into other substances. 



In a recent article Bokorny*" criticizes 

 the work of Kimpflin and others and main- 

 tains that the amount of formaldehyde 

 which would have to be present in the 

 plant in order to respond to any of the 

 known tests would certainly destroy the 

 vitality of the plant. He maintains, how- 

 ever, that it is undoubtedly present, but in 

 such minute quantities at any given period 

 that the only hope for its detection lies 

 in the discovery of some agent which would 

 combine with the aldehyde as fast as gen- 

 erated to form a compound that is not 

 toxic to the plant and from which com- 

 pound it could again be recovered in quan- 

 tities sufficient to respond to the standard 



'^Proo. Royal Soc, B, 77, p. 370. 



*° Arch. ges. Physiol. (Pflilgers), 125, p. 484. 



tests. It may be added that this is prac- 

 tically what Kimpflin attempted. 



THE ASSIMILATION OF FOEMALDEHTDE BY 

 PLANTS 



No single evidence perhaps would count 

 so much towards corroborating Baeyer's 

 hypothesis as the proof of the power of 

 plants to assimilate free formaldehyde 

 with the production of carbohydrates. It 

 is natural therefore that many experiments 

 have been made to ascertain just what ef- 

 fect formaldehyde has on the growing 

 plant. In conducting such experiments 

 naturally the formaldehyde would have to 

 be administered in very dilute solutions; 

 moreover, the amount of such solutions 

 would have to be large in order to obtain 

 a sufficient amount of formaldehyde to 

 effect a sensible amount of any assimilation 

 product. 



The first investigator to make any ex- 

 tensive study of this question was Bok- 

 orny,*^ who attempted to grow certain 

 water plants (green filaments of Spiro- 

 gyra) in dilute solutions of formaldehyde. 

 He found that formaldehyde, even in solu- 

 tions of 1 to 50,000, was fatal to the growth 

 of the plant. Next the attempt was made 

 to substitute for the free formaldehyde 

 some substance which under the influence 

 of the plant would slowly decompose, giv- 

 ing formaldehyde as one of the decomposi- 

 tion products. Such a substance Bokorny 

 found in methylal which decomposes into 

 formaldehyde and methyl alcohol and also 

 in the sodium acid sulphite addition prod- 

 uct of formaldehyde. By the use of these 

 compounds Bokorny hoped to diminish the 

 concentration of the actual aldehyde to the 

 minimum and yet by its constant forma- 

 tion furnish a sufficient amount of it to 



*^Ber. d. hot. Gesell., 1888, p. 119; Ohem. Zeit., 

 44, p. 525; Phar. Post, 36, p. 153; Biolog. 

 GentralU., 12, No. 16 and 17. 



