BUILDING OF LIVING MATTER 119 



basic group similarly, as N<^ , then the union 

 can easily be shown graphically, thus : — 



cooh - a - n <^h61oc-b-n/ ] 



An acidic and basic end come together, the 

 elements of a water molecule are detached, 

 as indicated by the dotted line, and all the 

 rest forms a reduplicated amino-acid. 



It is to be noted next that the whole larger 

 complex is still an amino-acid, for at one 

 end it has still an acid group, and at the other 

 a basic group. The process is analogous to 

 two magnetized particles coming together 

 by a north and a -south pole, when the double 

 particle has still a south and a north pole, 

 and hence is still a magnet. 



This process can go on so far as molecular 

 stability will allow, and the products formed 

 are called polyamino-acids, or, as the master- 

 worker at them, Emil Fischer, suggests, they 

 may be called poly-peptides, from their 

 resemblance in their properties to the natural 

 products obtained when proteins begin to be 

 disrupted by pepsin in digestion in the stomach. 



Fischer and his co-workers have made 

 artificially some hundreds of these poly- 



