28 ELEMENTARY BIOLOGY 



be planned to show whether, in addition to water, air also is 

 necessary for sprouting. In the same way we can go on and 

 try out the possible influence of light. 



45. Summary. Since it is possible to get seeds to sprout without 

 any soil at all, and without any of the ingredients of the soil other than 

 water, it is safe to say that none of these ingredients is essential to 

 germination. They may indeed be essential to the later growth of the 

 young plant ; but that is another story. 



We may learn from these experiments that the sprouting of a seed 

 depends upon an adequate supply of water, upon a supply of air, and 

 upon the temperature remaining within certain limits. We may learn 

 that the soil, in which most seeds do actually sprout, is not itself 

 necessary for sprouting ; and that the light, which is really of great 

 importance to life, has nothing to do with sprouting. 



