66 



PHYSIOLOGICAL CHEMISTRY. 



more facts were brought to light, so that finally a grouping 

 like the following came to be gradually accepted by physio- 

 logical chemists, with slight differences in details only. The 

 arrangement below is that of Hammarsten, in the form given 

 by Cohnheim. He makes four principal divisions as follows : 



PROTEIN BODIES < 



TRUE OR NATIVE ALBUMINS. 



DERIVED ALBUMINS OR TRANSFORMATION 



PRODUCTS. 

 PROTEIDS. 

 v ALBUMOIDS. 



These four great divisions may be further subdivided : 



Albumins proper. 



Serum albumin, egg albumin, lactalbumin. 

 Globulins. 



Serum globulin, egg globulin, lactoglobulin, ' 



cell globulin, vegetable globulin. 

 Coagulating albumins. 



Fibrinogen, myosin, gluten protein. 

 Nucleoalbumins. 



Casein, vitellins, mucin-like nucleoalbumins. 

 Histones. 



Scomber-histone, salmo-histone. 

 Protamines. 



Salmin, clupein, sturin, scombrin. 



DERIVED OR f Coagulated or Modified Albumin. 

 TRANSFORMATION < Acid and Alkali Albumins, Albuminates. 

 PRODUCTS. I Albumoses, Peptones. 



Nucleoproteids. 



Nucleinic acid with histone, protamine, etc. 

 Hemoglobins. 



PROTEIDS. \ Hematin with histone. 



Glucoproteids. 



Combination of a protein and carbohydrate 

 group, mucin, mucoids, phosphoglucoproteids. 



TRUE OR NATIVE 

 ALBUMINS. 



ALBUMOIDS. 



Collagen, forming gelatin, glue. 

 Keratin, in horn, hair, nails, etc. 

 Elastin, elastic tissue. 

 Amyloid, in pathological formations. 

 Spongin, in sponge. 



GENERAL REACTIONS OF THE PROTEINS. 



The various substances in the protein group respond to a 

 number of reactions which, taken together, are sufficient to 

 characterize and identify the bodies in question. They all 

 contain nitrogen in a form to be liberated as ammonia when 



