Seeds and Their Germination. 19 



way as the sprout grew. We have been taught by our 

 growing seeds that the sprout will take a vertical position. 

 We do not yet see what causes it to do so, but we are sure 

 of the fact. Now suppose the sprout grows one inch and is 

 yet erect and smooth, will the tip be an inch 

 deeper in the sand? will the head, bearing 

 the cotyledons, be an inch higher ? or will 

 each end move the one up, the other down 

 a half inch ? This is a simple mechanical 

 problem which you ought to be able to 



1 /TM 1 j_ r , 1 i Fi S- 14 - Bean sprout- 



Solve. The weight of the bean is not great ing in sand. 



enough to make it sink perceptibly in the sand, so we con- 

 clude that gravity practically has nothing to do with the 

 result. The fact that the plant is alive may be important 

 in considering how it keeps upright ; but life cannot make 

 a smooth stem move up rather than down, or the reverse, 

 without it does something more than get longer, and keep 

 stiffly erect. If you push up against a ceiling five pounds, 

 do your feet press down five pounds more than your weight ? 

 If you place a pin erect upon a potato and push down upon the 

 head with your finger, will the pin go point foremost into 

 the potato or head foremost into your finger ? If you 

 reverse the pin and push against the point, what will 

 be the result? Now look at the figure of the growing 

 bean and imagine a real bean in sand or soil. As the stem 

 gets longer will the point push deeper into the sand or will 

 the top with the cotyledons move up through it ? 



We have learned that before the growing caulicle of a 



