GENERAL BIOLOGY 



3. You have already observed the action of ptyalin on starch, 

 and of pepsin on albumen. Write the chemical formula for the 

 former of these reactions. 



V. HORMONES (Chemical Messengers). 



Chemical substances, possibly enzymes, usually formed by duct- 

 less glands and poured into the blood. They stimulate or inhibit 

 many vital processes (Thyroidin, Adrenin, Secretin, etc.) 



VI. VITAMINS. 



Accessory food substances of unknown chemical nature, pro- 

 duced by animals and plants. May act as enzymes or hormones. 

 Essential to life, but minute quantities sufficient. (" Water-soluble 

 B," "Fat-soluble A," etc.). 



VII. PROTOPLASM. (Living substance, material basis of 

 life). 



Composed of all the preceding classes of substances together 

 with water and various salts. Protoplasm is not a single chemical 

 compound but is an organized mixture of many compounds, espe- 

 cially proteins. There are innumerable kinds of protoplasm. 



B. MORPHOLOGICAL AND PHYSIOLOGICAL 

 CHARACTERISTICS OF LIVING THINGS 



Protoplasm exists only in the form of cells, which are in- 

 dividual masses of protoplasm, each containing a denser body, 

 the nucleus. 



I. CELL STRUCTURES. 



Read: Calkins, Biology, pp. 6-29; or 



Sedgwick and Wilson, General Biology, pp. 20-40 ; or 

 Parker, Elementary Biology, pp. 56-79; or 

 Shull, Animal Biology, pp. 70-83; or 

 Woodruff, Foundations of Biology, pp. 6-29. 



A. PLANT CELLS. 



i. Carefully tear in two a leaf and from the torn edge pick 

 off a small piece of the transparent covering (epidermis). Mount 

 in water and examine under the microscope. Draw about 10 ad- 

 jacent epidermal cells, making each cell about half an inch in 

 diameter. 



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