CHAPTER I. THE SEED 

 I. THE STORAGE OF FOOD IN SEEDS 



Material. — In addition to the four food tests described in Exps. 

 1-6, there should be provided some raw starch, a solution of grape 

 sugar, the white of a hard-boiled egg, and any fatty substance, sucli 

 as lard or oil. For Exps. 8 and 9, a little diastase solution will be nec- 

 essary. "Taka" diastase, made from rice acted upon by a fungus, can 

 be obtained for a trifle at almost any drug store. 



Living material. — Grains of corn and wheat, and seeds of some 

 kind of bean, the larger the better. The "horse bean" (Vicia faba), if 

 it can be obtained, makes an excellent object for study, as the cells are 

 so large that they can be seen with the naked eye. For showing the 

 presence of proteins (aleurone grains) and oily matter, use thin cross sec- 

 tions through the kernel of a castor bean or a Brazil nut. Specimens 

 for the study of the individual cell will be found in the hairs growing on 

 squash seedlings, in the epidermis of one of the inner coats of an onion, in 

 the roots of oat or radish seedlings, or in the section of a young corn root. 



A compound microscope will be required for this study. 



I. The economic importance of seeds. — As a source of 

 food to both man and the lower animals, the importance of 

 seeds can hardly be overrated. All the flour, meal, rice, 

 hominy, and other breadstuff s sold in the market come from 

 them, to say nothing of the fleece from the cotton seed that 

 clothes the greater part of the world, besides furnishing a 

 substitute for lard and an important food for cattle. The 

 oils and fats stored in nuts are also to be taken into account, 

 the peanut alone yielding the greater part of the so-called 

 olive oil of commerce. Since the value of our farm crops 

 depends largely upon the kind and quantity of these sub- 

 stances furnished by them, it is worth our while, as a matter 

 of economic as well as scientific interest, to learn something 

 about the nature of the different foods contained in plants. 



nOfERU LIBRARY 



