CLASSIFICATION OF ALBUMINS 349 



vitellines, nucleo- albumins of the cell -protoplasm, mucoid 

 nucleo-albumins. 



7. Histones. 



8. Protamins. 



II. Transformation-products 



1. Acid-albumins and alkali-albuminates. 



2. Albumoses, peptones, and peptids. , 



3. Halogen-albumins, oxy protein, oxyprotsulphonic acid, and allied 



substances. 



III. Proteids 



1. Nucleo-proteids. 



2. Haemoglobin and allied substances. 



3. Glyco-proteids, mucins, mucoids, helico-proteid. 



IV. Albuminoids 



1. Collagen. 



2. Keratin. 



3. Elastin. 



4. Fibroin. 



5. Spongin, etc. 



6. Amyloid. 



7. Albumoid. 



8. Colouring-matters derived from albumin. 



The transformation-products have already been discussed in the first 

 part of this book, while the native albumins will be discussed in this 

 second part. 



In what respect albumins differ from other substances has already 

 been stated, and the reasons why peptids and protamins may be 

 regarded as albumins have also been given. 



Cohnheim l says : ' No definite answer can be given to the question 

 whether corresponding albumins of different animals are identical or not. 

 The difference between the caseins of cow's milk and woman's milk is 

 so great as regards composition and reaction as to leave no doubt that 

 these two caseins are different substances. Haemoglobins, on the other 

 hand, agree almost completely apart from their solubilities. The 

 serum-albumins and serum-globulins, the muscle-albumins, etc., show 

 more or less distinct and constant differences as regards percentage- 

 composition, coagulation-temperature, and rotatory power. The serum- 

 albumins of the horse and of the rabbit crystallise, while those of all 



1 The author's views are given on p. 351. 



