92 THE PROTEIN SUBSTANCES 



III. Derived Proteins. 



1. PRIMARY PROTEIN DERIVATIVES. 



A. Proteans. 



B. Metaproteins. 



C. Coagulated proteins. 



2. SECONDARY PROTEIN DERIVATIVES. 



A. Proteoses. 



B. Peptones. 



C. Peptides. 



Classification of proteins adopted by the British Medical Association: 



I. Simple Proteins. 



1. Protamines. 



2. Histones. 



3. Albumins. 



4. Globulins. 



5. Glutelins. 



6. Alcohol-soluble proteins. 



7. Scleroproteins. 



8. Phosphoproteins. 



II. Conjugated Proteins. 



1. Glucoproteins. 



2. Nucleoproteins. 



3. Chromoproteins. 



III. Products of Protein Hydrolysis. 



1. Infraproteins. 



2. Proteoses. 



3. Peptones. 



4. Polypeptides. 



To this summary must be added that we often find in the investiga- 

 tions of animal fluids and tissues protein substances which do not fall 

 in with the above schemes, or are classified only with difficulty. At the 

 same time it must be remarked that bodies will be found which seem to 

 rank between the different groups, hence it is very difficult to sharply 

 divide these groups. 



