170 THE NATURE AND WORK OF PLANTS 



germinate, but if actually put into boil- 

 ing water and permitted to absorb the 

 warm liquid, it will be killed. On the 

 other hand, seeds of many common 

 plants may be bathed in liquid hydro- 

 gen at a temperature of four hundred 

 and twenty degrees below freezing point 

 and still retain the power of germination. 



V. The dissemination of the seeds. 



a. Could dissemination take place by water 

 or wind ? 



h. If you can observe a field of corn, note 

 whether any animals carry away the 

 grains or not, and if so what is done 

 with them. Are all of them destroyed ? 

 It would also be interesting to make 

 similar observations on the acorns of 

 the oaks. 



Man has been an important factor in 

 the distribution of corn, and his method 

 of growing and treating it has resulted 

 in the development of new species and 

 „ varieties. It is cultivated over great 

 areas, and although the larger number 



