CHEMISTRY 



221 



CH 3 



I 

 CH 2 



CH 3 



I 

 CH 2 



CH 3 



I 

 CO 



CH 3 



I 

 CO 



CH 2 OH COOH CH 3 CHO 



Propyl alcohol, Propionic acid, Acetone, Methyl glyoxal, 



Of the above substances, acetone, lactic acid, 

 glycerine, glycerine aldehyde, dioxyacetone, 

 alanine, serine, and cysteine are of the great- 

 est moment in physiological processes. 



Such complexity of chemical relationships 

 results automatically, so to speak, in a variety 

 of chemical transformations. But the trans- 

 formations are greatly facilitated by that 

 characteristic instability of organic substances, 

 which is perhaps the chief distinguishing fea- 

 ture of their behavior. For example, many 

 inorganic substances may be subjected to very 



