20 



THE STORAGE OF ENERGY 



proi'iniate principles of food) and a few other substances of minor 

 importance as storehouses of energy. 



Having regard to the fact that free energy is of vital import- 

 ance, and that the potential energy of the foodstuffs is readily 

 rendered available, one would consider it a profitable study to 

 determine the exact mechanism of this conversion. So far, study 

 of pure chlorophyll has led to negative results. Kremann and 

 Schnidlerschitsch have shown that pure chlorophyll, in alcohol, 

 absorbed the same amount of COo as the alcohol itself, and it 



K 



CHLOROPHVLL A 



ri I I I I ' '^'-' I I ' ' ' I ' 



700 650 600 550 

 B C D 



500 



450 



400 



CHLOROPHYLL B 



Fig. 2. — Absorption spectra of chlorophylls A and B. 00312 ?ram in ether 

 Thicknesses 5, 20 and 40 mm. (After Willstiitter, Stoll and Utzinger.) 



made no difference whether the solution were exposed to light or 

 kept in the dark. The absorption spectrum of neither chlorophyll 

 a nor chlorophyll b nor chlorophyll a -{- b is quite similar to the 

 spectrum of tlie living green leaf. Knowledge is incomplete both of 

 the chemical nature of the various constituents of the chloroplast 

 and of the distribution and physical state of the components of this 

 heterogeneous system. The pigments are associated with a colloid 

 complex : and the absorption of COg is accompanied by alterations 

 in the electrical state. 



Moore and his co-workers have proved that inorganic colloidal 

 uranium, iron and aluminium hydroxides act as catalysts in this 



