CH. VI] GROWTH. 143 



under a running tap for a minute. The sawdust or other 

 material should be prepared for the reception of the seeds 

 in a flat vessel of galvanised iron, 50 cm. in diameter and 

 6 cm. deep, in which the dry sawdust is placed and is 

 gradually moistened, mixing it thoroughly with the hands 

 as the water is added. Large flower-pots will serve for 

 germination of the seeds; they should be loosely filled 

 with damp sawdust, and when the seeds have been added 

 they may be covered with crockery plates or sheets of 

 glass. Beans seem to thrive best at a temperature of 

 about 15 C., peas and Phaseolus may have a slightly higher 

 temperature. 



Beans should be placed in the sawdust with the plane 

 of the cotyledons vertical and the hilum downwards : the 

 radicle thus grows out without curving, and the seeds are 

 ready for cultivation as shown in fig. 33, Chap, vii., where 

 they are supported on pins stuck into the cork lining of the 

 cover of a jar. Peas must be pinned through both coty- 

 ledons, it is therefore necessary to let them germinate 

 with the plane of the cotyledons horizontal; the same 

 position is convenient for Phaseolus. 



(167) Free oxygen necessary. 



Place 6 peas in water: when they are soaked remove 

 the testas, measure the length of the radicle in each, and 

 pass the peas up into an inverted test-tube of mercury, 

 as described in exp. 6, p. 10, on intramolecular respiration. 

 After from 12 to 18 hrs. measure the radicles, which will 

 be found either not to have grown perceptibly or to a very 

 slight degree. 



