JOHN S. GOULD'S ADDRESS. 615 



experiments, that the relative amount of these rays vary with 

 the changes of the seasons. In the spring, a solar beam con- 

 tains the greatest proportion of chemical rays ; in summer the 

 greatest proportion of light, and in autumn the greatest pro- 

 portion of heat. The action of these solar rays is adverse to 

 germination, because they prevent the formation of diastase, 

 which, as we shall see, is indispensable in the early stages of 

 the plant. 



The fourth point to be noticed in the process of germination 

 is access of atmospheric air. It is impossible for germination 

 to go on in the absence of air, even when all the other condi- 

 tions of warmth, moisture, and seclusion from light are the 

 most favorable. Thus we see seeds, which have been depos- 

 ited deep in the ground for years without germination, have 

 sprouted readily when brought to the surface and allowed to 

 come in contact with the atmosphere. 



If a few kernels of corn are made to germinate under an 

 inverted tumbler, it is found that though there is no material 

 change in the bulk of the air contained in it, yet there has 

 been a most marked change in its chemical composition. The 

 oxygen is absorbed and its bulk is replaced by carbonic acid. 

 This proves that the absorption of oxygen is essential to ger- 

 mination, and accounts for the necessity for the presence of 

 air, which is the great reservoir of this element. You are 

 aware that after the plant begins to unfold its leaves, and to 

 derive its whole nourishment from the soil and the atmosphere, 

 it gives out oxygen and absorbs carbonic acid, as long as it is 

 acted on by the chemical solar ray ; but when that is with- 

 drawn, and the earth is covered with the mantle of night, it 

 entirely reverses its operations ; it then gives out carbonic acid 

 and absorbs oxygen. Now, as we have seen, that the germin- 

 ating plant must perform the latter process, and that the 

 chemical portion of the solar ray induces an expulsion of 

 oxygen, we see an additional reason for guarding our seeds 

 from the intrusion of light. 



I trust I shall not be accused of trifling with your time in 

 dwelling so long on these matters, apparently so trivial. I do 

 not so consider them. Much of the vigor of a plant and the 

 amount of its produce depend upon its germination. If this 

 is effected under circumstances the most favorable to its progress, 



