THE SEED, GEHMINATION AND THE PLANTLET 15 



The water content of the medium with which they are in 

 contact. — If we place one lot of beans in water, a second in 

 wet earth and a third in slightly damp earth, we shall find 

 that the first lot will swell most rapidly, the second next 

 and the third slowest. Few seeds will absorb enough 

 water from damp air at ordinary temperatures to swell 

 much. 



The points of contact. — If we weigh two lots of 100 

 beans each, on a delicate balance, and mix each lot with 

 well-crumbled, moist loam in a fruit-jar, packing the loam 

 tightly in one of the jars, and leaving it as loose as possible 

 in the other, close both jars to prevent evaporation, and 

 after twenty-four hours sift the beans out of the loam and 

 weigh the two lots again — ■ we shall find that the beans in 

 the jar containing the compacted loam have increased 

 more in weight than the others. This indicates that the 

 beans in this jar have absorbed water faster than those in 

 the other, because they were in contact with the moist 

 loam at more points. 



Temperature. — If we fill two bottles with beans, adding 

 ice water to one, placing it in a refrigerator, and lukewarm 

 water to the other, setting it in a warm room, we shall 

 find that the beans in the latter bottle will swell more 

 rapidly than those in the former. This shows that a warm 

 temperature favors the absorption of water — a fact that 

 is true of all seeds. The same would have been true had 

 we planted the beans in two samples of moist earth, 

 placing these in different temperatures. 



The nature of the seed-case. — In the bean, Indian corn, 

 wheat and many other seeds, the seed-case is of such a 

 nature that it absorbs and transmits water readily. In 

 certain seeds, however, as of the honey locust, canna, 

 thornapple and the like, especially if they have been 



