228 PRACTICAL BOTANY 



scutellum the starch-grains are in course of demolition, 

 and that the central part of each is first attacked. 



2. That no starch-grains are to be seen in the 

 epithelium of the scutellum. 



Seeds of the Date should also be sown, and the 

 process of germination followed : it may then be seen 

 that the cotyledon, which remains in contact with the 

 endosperm, exhausts the substance of it, gradually 

 increasing the cavity in which the embryo originally 

 was : meanwhile the body of the embryo, with plumule 

 and radicle, is pushed out from the cavity, owing to the 

 increase in length of the cotyledon. 



Asparagin. 



This substance is found in most seedlings, but in 

 specially large quantity in those of Lupinus lutcus. Cut 

 sections from fresh seedlings, and, after a preliminary 

 examination of them, irrigate gradually with alcohol : 

 the substance is precipitated in the form of crystals. 



Sections of material which has been kept in alcohol, 

 mounted in glycerine, will show these crystals already 

 formed, and often of large size. These sections should 

 be irrigated with water ; the crystals will dissolve. 



The most distinctive test is a saturated solution of aspa- 

 ragin : if this be added to sections containing crystals 

 presumably of asparagin, they will not be dissolved, 

 whereas crystals of inulin would be dissolved. 



