SCIENCE PRIMERS. 



[vi. 



remain dry the seeds will not grow. Moisten them 

 and put them where the temperature does not rise 

 above freezing ; still they will not grow. Place them 

 in a vessel from which all air is excluded still they 

 will not grow. Lastly, place them where the tem- 

 perature is considerably above freezing, and where 

 air has access to them, and keep them moist, and 

 they will grow, whether in light or shade. This 

 growth of a seed is called its germination. 



34. From these experiments we learn that to produce 

 germination in a live seed, water, air, and a heat con- 



FIG. 10. T Pea, 2 Radicle pushing through Integument, 3 Embryo with 



Radicle elongated, 4 the same with one Cotyledon removed, 5 the same 



further advanced ; all twice the real size. 



siderably above the freezing point are all required. 

 And what is thus proved of the seed applies to plants 

 throughout their lives namely, that to grow they 



