INTRODUCTORY 9 



is secured between two halves of a cork with a hole in the 

 middle. The cork is fitted into the neck of the bottle so that 

 the roots are entirely submerged in the liquid and the stem 



FIG. 1. 



erect in the air, as shown in the illustration (Fig. 1). This 

 method possesses certain advantages. Sand and every- 

 thing else except water, which has to be used in any case 

 are entirely dispensed with. The solution is absolutely 

 homogeneous throughout. It can be diluted to any extent 



