GROWTH OF PLANTS FROM THE SEED. 27 



and careful experiments go to show that seeds sprout 

 more promptly and surely with a less amount of water 

 than is commonly supplied in artificial cultures. Too 

 high or too low a temperature is equally unfavorable, 

 although there is a pretty wide range within which most 

 seeds will germinate. An even temperature is found to 

 be more favorable to prompt germination than a variable 

 one. Finally, if oxygen is excluded, even if all other con- 

 ditions are fulfilled, germination fails to take place. It is 

 for the purpose of securing an abundant supply of oxygen 

 that we leave the sawdust lying up loosely, rather than 

 closely packed, about the seeds, when we are raising seed- 

 lings in the laboratory. For the same reason, a light, 

 loose soil is more favorable for gardening than a compact 

 and heavy one. These conditions are well known, and 

 are taken into account in practical operations, although a 

 comparison of different seeds during germination estab- 

 lishes the equally important fact that both individual and 

 specific peculiarities exist. Some seeds require more 

 moisture than others, and the degree of temperature most 

 suitable for germination varies with different species, ^and 

 so on. An interesting series of experiments on the condi- 

 tions of germination and the individual peculiarities just 

 referred to has been carried out at the Cornell University 

 Experiment Station. For an account of these, see Science, 

 XIV (1889), p. 88. 



Some of the phenomena connected with germination are 

 of much interest and are easily observed. The first step 

 consists in the forcible absorption of water, Attendant phe- 

 manifested by the great increase in size of ger- nomena. 

 minating seeds, and the pressure they exert if an attempt 

 is made to confine them in a closed vessel. Testing with 

 a thermometer shows that the process of germination is 



