STORAGE OV NOURISHMENT IN THE SEED. 25 



by the solution of nitrate of mercury known as Millon's 

 reagent.^ 



36. Experiment 12. — Extract the germs from some soaked 

 kernels of corn and bruise them, soak some wheat-germ meal for a few 

 hours in warm water, or wash the starch out of wheat-flour dough, place 

 in a white saucer or porcelain evaporating dish, moisten well with 

 Millon's reagent or with nitric acid and examine after fifteen minutes.^ 



37. Other Constituents of Seeds. — Besides the substances 

 abovfi suggested, a variety of others occur in different seeds. 

 Some of these are of use in feeding the seedling, others are of 

 value in protecting the seed itself from being eaten by ani- 

 mals or iii rendering it less liable to decay. In such seeds 

 as that of the nutmeg, the essential oil which gives it its 

 characteristic flavor probably makes it unpalatable to animals 

 and at the same time preserves it from decay. 



Date-seeds are so hard and tough that they cannot be eaten 

 and do not readily decay. Lemon and orange seeds are too 

 bitter to be eaten, and the seeds of the apple, cherry, peach, 

 and plum are somewhat bitter. 



The seeds of larkspur, thorn-apple,' croton, nux vomica, 

 and many other kinds of plants contain active poisons. 



1 See Appendix B. 



2 It may be found interesting to test a very oily seed, suoli as the Brazil-nut, for 

 starch, oil, and proteids, and then discuss the question whether any two of these 

 three substances are apparently interchangeable, that is, whether if the plant has 

 one it also needs the other. 



* Datura, commonly called " Jimpson weed." 



