6 Feeds and Fixding. 



are imposed of the same three elements found in the carbo 



hydrate group, the hydrogen atoms are not always twice the 



number of oxygen atoms. Thess oils are usually compounded 



of several simple oils, the principal of which, with their formulse, 



are as follows: 



Stearin C,,TL,,,0^ 



Palmitin CsiHggOe 



Olein G,,B.,,,0, 



Oils give off much more heat during combustion than the car- 

 bohydrates because they contain a relatively larger quantity oi 

 carbon. While found in nearly all parts of the plant, the oils and 

 fats are chiefly stored in seeds, as flax, cotton, rape, etc. Oats, 

 wheat and corn contain some fats or oils. 



9. Protein compounds. — Thus far we have considered the 

 plant compounds which result from the union of the three ele- 

 ments, carbon, hydrogen and oxygen. We now come to a more 

 complex group of plant substances containing two additional ele- 

 ments, viz., nitrogen and sulfur. It is held that the nitrates 

 taken up through the roots of plants on reaching the protoplasmic 

 masses in the active cells are broken up, and the nitric acid and 

 sulfur are united with starch or a starch derivative, forming a 

 protein compound. Protein substances may be produced in pro- 

 toplasmic masses which may or may not contain chlorophyll. The 

 protoplasm of active cells, where the work of assimilation goes 

 on, is itself a protein substance. Very little protein is found in 

 the woody, older portions of the plant, the greater amount existing 

 at the point of growth and in the seeds or reproductive parts. In 

 the seed the protein exists quite largely in the germ itself, and 

 also in the surrounding envelopes. For a definition of protein, 

 see Glossary. The protein compounds of plants are divided into 

 two groups — albuminoids and amides. 



10. The albuminoids. — One group of protein substances is 

 characterized by the term '' albuminoids." "Vegetable albu- 

 men closely resembles the white of Qgg, and like it, is coagulated 

 by heat. Gluten, another albuminoid, is found in the wheat 

 grain. It may be separated from tlie starchy portion of wheat 

 flour by washing the dough in running water, the sticky mass 



