CHAPTER VII 



AIR AND SOIL IN RELATION TO SPROUTING 



46. Sprouting and transformation of energy. The fact that 

 air is in some way necessary for sprouting suggests that the 

 activity of the plant is in some way similar to the process of 

 burning. Further experiments show closer resemblance — for 

 example, the fact that it is the oxygen of the air that is con- 

 cerned in both processes, and the fact that in both processes 

 the transformation of energy results in the liberation of heat. 

 Moreover, in both cases there is set free a quantity of an oxid 

 — in this case carbon dioxid, as in the case of fires using car- 

 bon or carbon-containing materials as the fuel. When we com- 

 pare these three conditions with what we find in familiar 

 animals, — our own bodies, for example, — we see a similarity 

 that suggests the possibility of all living things carrying on the 

 same fundamental process. And, indeed, it is proper to speak 

 of the young plants in the sprouting seeds as "breathing," 

 and to speak of the chemical changes going on inside the 

 living matter of plants and of animals as "oxidation." 



There are very many different chemical processes going on in 

 living things. Oxidation is only one of them. But it seems to 

 be nearly universal, and it seems to be the one that makes avail- 

 able to living matter the energy for its various other activities. 



47. The soil and the young plant. We saw that seeds can 

 sprout without depending upon the soil. Yet we know that 

 the soil is essential to the growth of plants. This means that 

 although the young plant in the seed is for a time independent 

 of any soil materials, there comes a time in the course of its 

 development when further growth is possible only on condition 

 of receiving various substances from the soil. 



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