96 GENERAL BIOLOGY 



Inorganic. 



A. Always present, and called essential elements. 



H 2 O 



Plus C, H, N, K, Ca, Na, Fe, NH 4 . 

 Minus CO 2 , SO 4 , Cl, PO 4 . 



B. Sometimes present. 



I, Br, NO 2 , NO 3 , Zn, Ba, Cu, Mn, As, Fl, Si, Mg. 

 Muttkowski has summarized the chemical elements concerned in 

 living matter as follows : 



I. Elements concerned with Food. 



1. Those which compose food. 



A. Proteins C, O, H, N, (S, P) build protoplasm. 



B. Fats C, H, O energy and reserve. Certain P-fats 

 enter into building up of all protoplasm (lecithin). 



C. Carbohydrates C, O, H energy, and reserve. 



2. Elements concerned in food synthesis. 

 Mg, CO 2 (in plants only). 



3. Concerned with food storage K. 



4. Katalysts Fe, Ca, Mn, I. 



II. Elements concerned with Physiological Processes. 



1. Regulation (turgor, toxicity) K, Cl, Na, Ca, I, Br. 



2. Sensory P. 



III. Elements concerned with structural relations. 



1. Form relations elasticity N, Cl. 



2. Supporting tissues C, Ca, Si, Mg, P, Fl, (S) in form of 

 phosphates, carbonates, oxalates. 



CELL DIVISION 



Every living thing, plant or animal, begins its life as a single cell. 

 Therefore it follows that if one wishes to understand how a many-celled 

 animal (metazoan) ( ) comes to its adult form of 



life, one must find an original single cell and follow it throughout all its 

 changes until it has come to adultship. 



Every living cell grows if it obtains food, and when it reaches its 

 maximum size splits in two. It may do this equally or unequally; 

 that is, it may split into a very large and a very small part, or it may split 

 equally into halves of like size and shape. There are then two cells where 

 there was only one before. These two cells then grow until the time 

 they attain their maximum size when the same process is gone through 

 again, so that in a short time there are four cells, then eight, sixteen, 

 thirty-two, sixty-four, one hundred twenty-eight, and so on. 



When the children's story is remembered of the blacksmith who 

 was willing to shoe the king's horse on Sunday provided the king xvould 

 pay one cent for the first nail, and double that for each nail he drove, 

 so that by the time the blacksmith had put in twenty-eight nails, he had 



