262 SCIENCE PROGRESS 



the same as the well-known Cannizzaro transformation brought 

 about by alkalies, 



C 6 H S . CHO + C 6 H 5 CHO -> C 6 H 5 CH a . OH + C 6 H 5 . CO . OH 



is explained by Mascarelli as involving the formation of benzoyl 

 iodide, C 6 H 5 . CO . I, as an intermediate product; although this 

 substance is not formed from benzaldehyde and iodine under 

 ordinary conditions, its production under the influence of sun- 

 light has been actually observed. 



Exactly similar changes occur in the case of /-tolualdehyde, 

 which gives toluylic toluate when exposed to sunlight. 1 



The foregoing cases of internal oxidation-reduction are of 

 special interest when considered in reference to the changes 

 which occur in the foliage leaves of plants. The recent work 

 of Strakosch and others would indicate that dextrose is the first 

 sugar formed in the leaf of the sugar beet by photosynthesis ; 

 if this be so, its transformation into lsevulose and hence into 

 cane sugar, in which form the sugar is stored in the root, is 

 a change closely analogous with the photo-chemical trans- 

 formation of the o-nitrobenzaldehydes. 



The part played by light in conditioning the numerous cases 

 of " autoxidation " which have lately attracted so much attention, 

 especially from Engler 2 and Manchot, has as yet been little 

 investigated. From the point of view of the changes occurring 

 in plants, more especially those brought about by the so-called 

 oxydases, such knowledge is particularly desirable. The recent 

 statement of Kernbaum 3 that he has observed the decomposi- 



1 Mascarelli and Russi, Gazzetta, 1912, 42, 92. 



* See Engler andWeissberg, Kritische Studien iiber die Autoxydations vorgdnge, 

 Vieweg, 1903. 



1 Bull, Acad. Set. Cracovie, December, 191 1, 583. 



