CHLOROPHYLL AND ENERGY 213 



atom quickly recovers the lost electrons, the conditions are 

 different if the nucleus is affected, for, at that level, the losses 

 or gains are definitive. The energy released by the destruction 

 of heavy nuclei such as those of uranium or plutonium, or 

 by the agglomeration of light nuclei such as those of hydrogen, 

 deuterium or tritium, is irretrievably lost to the atom, for 

 the nuclei formed are much more stable than those from 

 which they come. This needs no proof when one considers 

 the enormous quantities of energy liberated by these 

 transformations. 



A part of the initial mass is transformed into energy and 

 disappears; this has given physicists the hope that one day 

 they will be able to release, not a thousandth of the mass, 

 but the entire mass of the atom. Such a liberation seems 

 possible, but is still uncertain. 



From the point of view of their utilization, all these forms 

 of energy can be evaluated in electrical units. The conversion 

 from one form to another is easy, as is abundantly proved 

 by the generation of electricity from sources as different as 

 coal, waterfalls and the wind, and its utilization for hghting 

 or heating or for driving machines. 



There is, however, one form of energy which can be 

 evaluated in terms of electricity but which could not be 

 produced from electricity — the energy of oxidation-reduction 

 that the living organism claims unconditionally. It could 

 be called a noble, irreplaceable energy. Here the quality 

 matters much more than the quantity, for, considered from 

 that point of view, the balance would not be strikingly in 

 favour of the products derived from chlorophyll : 1 gramme of 

 glucose is capable of liberating in the organism or in the 

 calorimeter 4,000 calories, I gramme of uranium can produce 

 20,000,000,000 calories and 1 gramme of matter represents 

 21,000,000,000,000 calories. 



We have become accustomed to drawing up a balance 

 sheet of our resources of energy and are beginning to know 

 what may be of value to us. 



The energy of matter represents a capital that can be 



