246 APPENDIX 



seeds. The exalbuminous seed of the Norway Maple is interesting on 

 account of the very small store of food in the embryo. The " grain " 

 of Indian Corn, the "seeds" of Four-o'clock and Sunflower, the "pea- 

 nut" (including shell), and the key of the Maple are fruits. This 

 fact need not be brought forward, as the distinction between fruit and 

 seed will be made plain in the chapter on fruit. In the case of the 

 Peanut the question will arise, how much is a single seed ? Refer to 

 the like case of peas in a Pea pod. 2. The iodine used may be pre- 

 pared by dissolving the crystals in alcohol, or, better, in a strong 

 aqueous solution of iodide of potassium, which may be had from supply 

 companies and probably from druggists. In testing for starch, if the 

 iodine is too strong, the characteristic blue tint will be obscured. 

 Use the reagent diluted. In the Castor Bean, Flax, and Cotton, a con- 

 siderable part of the food takes the form of oil. In this connection it 

 will be well to present facts concerning the uses of oily seeds, and of 

 seeds in general. Or, better, the subject may be assigned, as a whole 

 or in parts, to one or more pupils for special reports. In the Date, the 

 reserve matter is in the form of " reserve cellulose." 



A test for proteid matters in seeds may be made as follows : Crush 

 the kernel of the given seed on a glass slide. Add a few drops of 

 concentrated nitric acid, and allow to act for a few minutes. If pro- 

 teid matter is present in quantity, a yellow or orange color appears, 

 which becomes more intense after the acid has been washed off and 

 strong ammonia water added. Contrast the color reaction in the 

 kernel of Sunflower seed with that in pulp of Potato, when treated 

 with nitric acid and ammonia ; also again when treated with iodine. 

 The compound microscope may be used in tests with iodine, and for 

 detection of oil. 



Exercise III. Experiment i. This may well be a demonstration 

 largely prepared by the teacher. The Beans should be ready after 2 

 days' soaking. The department of physics or of chemistry will sup- 

 ply some sort of simple hydrogen generator. One may be made of 

 flask, cork, and glass tubing, in the way described by elementary 

 chemistries. Fill the generator flask pretty well up with the acid 

 solution, in order to have as little air in the generator as possible. 

 (For the physiology of seeds and germination, see Goodale's "Physi- 

 ological Botany," Ch. XV.) Experiment 2. Several pupils may work 

 together on such experiments as this. The gas given off by the 

 sprouting Corn is the same as that from the human lungs, namely 

 carbonic acid gas. Respiration is the same in both plants and ani- 

 mals, as regards the intake (oxygen) and the exhaled product (carbon 

 dioxide) . (See " Respiration " Goodale, p. 367.) Experiment 3. The 

 thermometer used should be graduated in half degrees or finer ; or, at 

 least, the degree divisions should be long. Subdivisions of the spaces 

 may with care be estimated down to tenths by the eye. Of course, the 



