90 GENERAL BIOLOGY. 



SEED-CONTENTS. 



I. Pea. 



Cut thin sections of the cotyledons. Mount 

 some in dilute glycerine and others in 

 water. 



1. In the glycerine preparations observe in each 



cell: 



(a) Large starch-grains. 



(b) Small aleurone-grains. 



(c) Very finely granulated substance. 

 Observe the intercellular spaces. 



Sketch one or two cells with cell-contents. 



2. Compare the glycerine-preparation with the 



water preparation. 



Add iodine to the glycerine preparation. 

 What is the effect ? 



II. Bean. 



Examine as Pea. 



III. Wheat. 



Cut thin sections at right angles to the seed- coat y 

 and mount them in dilute glycerine. 

 Observe : 



(a) Just within the seed-coat a layer of rec- 



tangular cells containing aleuTone- 

 grains. 



(b) More centrally situated, cells containing 



starch. Add iodine. What is the 

 effect ? 

 Sketch a few cells. 



