1893.) On the Food of Green Plants. 409 
CO, and H,O in the presence of chlorophyll bodies furnished 
with radiant energy of sufficient intensity, there occurs a re- 
urangement of the molecules of C, H, and O into some simple 
_ ‘ompound, probably formic aldehyde. By definite changes, 
probably polymerization, this becomes more and more com- 
_ plex,until finally one of the higher carbohydrates is produced, 
generally one of the sugars. 
_T believe that these changes occur through the action of the 
living protoplasm of the chlorophyll body, but that the 
HCO, zs not brought into such relation to the proteid mole- 
cules as to form any part of them. The energy necessary to 
*complish the work is supplied in the form of light. The 
chlorophyll of the chromatophore acts as an absorbent of the 
"ays which are useful in doing the work, as Timiriazeff has 
shown,?? and not as a shield. 
The Process here described has been called ‘‘assimilation,” 
“assimilation proper,” and ‘‘assimilation of carbon.” I thin 
tnone of these terms is appropriate.'* Assimilation has 
en long used in animal physiology to designate the appro- 
_ Prlation of digested food by the different tissues, and its con- 
Yersion into the substances of those tissues. In that general 
weit ought to be used in vegetable physiology, or, if it 
ny hot be So used, it ought not to be used at all. We have 
whine tunity to use it so, if we apply it to those changes by 
x rm She Complex carbon compounds produced by the green 
oe are appropriated by the various tissues, and made a ek 
E hie sy Moreover, since in many instances the reserve (3 
7 Which a form, there is in plants a process of digestion # 
= 'S solid food is altered and dissolved in order that i 
| May be assimilated. 
out cf the process of formation of complex carbon sis ee 
Phe ic simple ones under the influence of light, I propose tha 
: 'M photosyntax be used.14 The protoplasm, by the 
la ee eee er ae 
: Me Enregistrement photographique de la fonction chlorophyl- 
C t 
Par la pl 
lag Plante vivant, mpt. Rend. cx (1890). 1346-7. ener 
f Wiesner: Elemente der wiss, Botanik 1. 232. ‘‘Unter Assimilation 
7 Wassers j . 
; t der al i : IE RE herrschenden, der- 
Rio} Assi; -teren, in der Thierphysiologie noch immer herrsc ; ; 
tee tion die Umwandlung die an tgeadcineeels Nahrungsmittel in 
e e os = ? 
q osu +f. DP. 33 
4 "22 bisher Dg an einem 
