THE BREATH OF LIFE 



cannot always cover the flea; this atom has will, and 

 knows the road to safety. Behold what our bodies 

 know over and above what we know! Professor 

 Czapek reveals to us a chemist at work in the body 

 who proceeds precisely like the chemist in his labo- 

 ratory; they might both have graduated at the same 

 school. Thus the chemist in the laboratory is accus- 

 tomed to dissolve the substance which is to be used 

 in an experiment to react on other substances. The 

 chemical course in living cells is the same. All sub- 

 stances destined for reactions are first dissolved. No 

 compound is taken up in living cells before it is dis- 

 solved. Digestion is essentially identical with dis- 

 solving or bringing into a liquid state. On the other 

 hand, when the chemist wishes to preserve a living 

 substance from chemical change, he transfers it from 

 a state of solution into a solid state. The chemist in 

 the living body does the same thing. Substances 

 which are to be stored up, such as starch, fat, or pro- 

 tein bodies, are deposited in insoluble form, ready to 

 be dissolved and used whenever wanted for the life 

 processes. Poisonous substances are eliminated from 

 living bodies by the same process of precipitation. 

 Oxalic acid is a product of oxidation in living cells, 

 and has strong poisonous properties. To get rid of it, 

 the chemist inside the body, by the aid of calcium 

 salts, forms insoluble compounds of it, and thus casts 

 it out. To separate substances from each other by 

 filtration, or by shaking with suitable liquids, is one 

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