PHYSIOLOGY. 



PART III -DIGESTION AND SECRETION, 



WITH INTRODUCTORY CHAPTERS ON THE ALBUMINOUS 

 COMPOUNDS, AND ON THE CHEMISTRY OF THE 

 TISSUES. 



BY DR. LAUDER BRUNTOK 



CHAPTER XXXY. 

 ALBUMINOUS COMPOUNDS. 



SECTION 1. PROPERTIES OP ALBUMIN. 



1. ALBUMINOUS bodies occur in all the tissues of the higher 

 i imals, and form the chief part of their bulk. They derive 

 t ; r name from white of egg, which may be taken as a type of 

 tlu ^roup, and thev all resemble one another very closely, both 

 in A operties anc* composition. They contain 52.7-54.5 per 

 cent, of carbon, 6.9-7.3 per cent, hydrogen, 20.9-23!5 per cent, 

 oxygen, 15.4-16.5 per cent, nitrogen, and 0.8-1.6 sulphur. In 

 the body they occur partly in a solid form and partly in solu- 

 tion. The herbivora derive them from vegetables in which 

 they are contained, and fie carnivora from the animals on which 

 they feed. They do not diffuse, and only a small part of the 

 albuminous matter taken as food passes through the walls of 

 the alimentary canal into the circulation unchanged. The 

 greater portion is converted into diffusible bodies nearly allied 

 to albumin, called peptones, which are readity absorbed. 



The organism not 01113' possesses the power of transforming 

 albuminous bodies of one kind into those of another, so that, 

 e. g., the casein of milk is converted into the muscles of the 

 sucking infant, but of combining them with other substances, 

 so as to form such compounds as the haemoglobin of blood, and 

 of altering them in such a way as to obtain from them the so- 



