I'l.ANT I'lIVSIULOCiY. I4I 



There are reasons for thinking that this reaction does not 

 exactly represent the change that takes place, but that the 

 chlorophyll, under the action of the sun's rays, combining 

 with the hydrogen, forms a hydride, the hydrogen being obtained 

 by the decomposition of water with liberation of oxygen. 

 This hydride of chlorophyll, or chlorophyllin, gives up its 

 hydrogen to the CO., and formaldehyde results: 



H., - CO, ^ CH,0 - O. 



In either case the first compound formed is formaldehyde, 

 which b)' polj-merizing forms C,. H,., O,. . It is thus that the 

 plant prepares sugar, and by changes in hydration forms 

 starch, cellulose, etc. The nitrogen of the plant is taken in as 

 ammonia or nitrates. The nitrogen taken in acts upon the 

 unpolymerized aldehyde, producing hydrocyanic acid, thus : 



2HNO, - 5CH.,0 - 2CNH - 3 CO., H 5H.,0. 



It may be noted in passing that the presence of hydrocyanic 

 acid has been observed in many plants, and, further, it has 

 been shown that hydrocyanic acid, in the presence of water 

 and formaldehyde, can form certain amides which have been 

 recognized among the decomposition products of albumen. 

 It is assumed, therefore, that the origin of the albuminoid 

 matter in the plant may be traced to some reaction between 

 the formaldehyde and the hydrocyanic acid. The albumen 

 once formed can then be transformed into other proteids. 



The alcove notes on plant physiology, collected as they are 

 from various sources, furnish food for much valuable thouoht. 



