138 PHYSIOLOGY OF THE DOMESTIC ANIMALS. 



not well known. The optical properties of chlorophyll are very remark- 

 able. Fresh alcoholic solutions in ether, even when very dilute, give a 

 broad band in the red line of the spectrum, and between the red and the 

 orange. The most luminous portions of the spectrum are the red and 

 green parts. When concentrated ethereal solutions of chlorophyll are 

 examined in the spectroscope, only the red rays pass. Concentrated 

 solutions of chlorophyll give a red fluorescence with reflected light. 

 When subjected to the action of light solutions of chlorophyll change their 

 color, probably in a manner similar to that which accompanies the vital 

 processes of the vegetable protoplasm in which chlorophyll is contained. 



In all its forms protoplasm, whether animal or vegetable, contains 

 albuminous bodies in a state of solution in water, and associated with 

 compounds of an inorganic nature. Carbo-hydrates, hydro-carbons, and 

 ferments are also nearty invariably present. It may be assumed that the 

 albumen is the highest and last product of the chemical activit}^ of vege- 

 table cells, while starch probably constitutes the first evidence of proto- 

 plasm activit} r , and is the mother-substance out of which other carbo- 

 hydrates, such as cellulose and sugar, as well as fats, are manufactured. 



Plants develop various modifications of albuminoids, which are 

 apparently identical with the different forms of albuminous bodies found 

 as constituents of animal cells. Thus, in growing and germinating 

 plants a globulin-like body is found in large amount, as well as a sub- 

 stance similar to myosin and vitellin in combination with lecithin and 

 certain inorganic substances. Albumen is found in especially large 

 quantities, with large amounts of starch, in the seeds of plants ; 

 hence, the undeveloped plant finds in these two substances, albumen and 

 starch, material ready prepared for building up its tissues until it 

 reaches a grade of development in which it is able to manufacture these 

 organic compounds from the elements. When the first leaves and roots 

 are formed, then the plant commences its independent existence. The 

 evidences of this, as we have already seen, consist in the appropriation 

 of C0 2 , H 2 and NH 8 , with a corresponding liberation of oxygen. 



Since all vegetable matters contain carbon and water, their con- 

 stituents may be regarded as more or less modified C0 2 molecules. 

 Thus, sugar may be regarded as CO, in which one equivalent of oxygen 

 is replaced by two equivalents of hydrogen (Liebig). 



Carbonic Anhydride. Grape-Sugar. 



'8 C H 2 



or6(CO 2 (H 2 0)) = 6(CH 2 O) -f 6O 2 = C 6 H 12 O 6 +6O 2 . 



Carbon dioxide, therefore, in the formation of organic matter, may 

 be regarded not as decomposed, but as changing the arrangements of its 

 molecules. We have found that plants in their nutritive purposes assimir 



