80 ALBUMINOUS MATTERS. 



which have as yet been so distinctly recognized as to receive specific 

 names. Many of them, perhaps all, contain a small amount of sulphur 

 in addition to their carbon, hydrogen, oxygen, and nitrogen. Their 

 chemical relation to other substances has not been found sufficiently 

 definite, in any case, to establish the formula for their atomic constitu- 

 tion. The average proportion, however, by weight, of their constituent 

 elements, according to the tables of Hoppe-Seyler 1 and Fremy, is as 

 follows : 



AVERAGE COMPOSITION OF ALBUMINOUS MATTERS. 



Carbon 52.0 



Hydrogen ...... 6.9 



Nitrogen 15.6 



Oxygen 24.0 



Sulphur ....... 1.5 



100.0 



One of the simpler physical characters of the albuminous substances 

 is that they are hygroscopic. ' As met with in different parts of the body, 

 they present different degrees of consistency ; some being nearly solid, 

 others more or less fluid. But on being subjected to evaporation they 

 all lose water, and may finally be reduced to the perfectly solid form. 

 If after this desiccation they be exposed to the contact of moisture, 

 they again absorb water, swell, and regain their original mass and con- 

 sistency. This phenomenon is different from that of capillary attrac- 

 tion, by which some inorganic substances or tissues become moistened 

 when exposed to the contact of water ; for in the latter case the water 

 is simply entangled mechanically in the meshes and pores of the inorganic 

 body, while that which is absorbed by the albuminous matter is actually 

 united with its substance, and diffused equally throughout its entire 

 mass. Every albuminous matter is naturally united in this way with a 

 certain quantity of water, some with more, some with less. Thus the 

 albumen of the blood is in union with so much water that it has the 

 fluid form, while the corresponding substance of cartilage contains less 

 and is of a firmer consistency. The quantity of water contained in each 

 albuminous substance may be diminished by artificial desiccation, or by 

 a deficient supply ; but it cannot be increased beyond a certain amount. 

 Thus, if the albumen of the blood and the albuminous matter of carti- 

 lage be both reduced by evaporation to a similar degree of dryness, and 

 then placed in water, the albumen will absorb so much as again to be- 

 come fluid, but the cartilaginous substance only so much as to regain 

 its usual nearly solid consistency. Even where the organic substance, 

 therefore, as in the case of albumen, becomes fluid under these cir- 

 cumstances, it is not precisely by its solution in water, but only by its 

 reabsorption of that quantity of fluid with which it was naturally 

 associated. 



1 Handbuch der Physiologisch- und Pathologisch-Chemischen Analyse. Berlin, 

 1870. 



