OTHER CONSTITUENTS OF SEEDS 11 



result of the action of its diastase, malt tastes much sweeter 

 than barley. The capacity of this enzyme to change starch to 

 sugar is extraordinary, any quantity of diastase sufficing to trans- 

 form ten thousand times its weight of starch. 



11. Oil. Oil occurs in many seeds as, for example, flax, cot- 

 ton seed, and corn in sufficient quantity to make it worth while 

 to extract it by pressure. It may be seen under the microscope in 

 extremely minute droplets, inclosed in the cells of certain regions 

 of the seed. 



12. Proteids. Sometimes, as in Fig. 6, at p, the proteid con- 

 stituents of the seed occur in more or less regular grains, but 

 often they have no well-defined form and size. They have a 

 chemical composition very similar to that of white of egg or 

 the curd of milk, and when scorched produce the familiar smell 

 of burnt hair or feathers, which serves as a rough test for their 

 presence. 



13. Other constituents of seeds. Besides starch, oil, and pro- 

 teids, other substances occur in different seeds. Some of these 

 are of use in feeding the seedling, others are of value in protect- 

 ing the seed itself from being eaten by animals or in 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, orange, horse-chestnut, ai:cl 

 buckeye seeds are too bitter to be eaten, and the seeds of the 

 apple, cherry, peach, and plum are somewhat bitter. 



The seeds of larkspur (Datura]} croton, the castor-oil plant, 

 nux vomica, and many other kinds of plants, contain active 



poisons. 



1 Commonly called Jirnson weed. 



