02 INTRODUCTION. 



undoubtedly be found to vary considerably within the limits 

 of health, and, as a rule, it bears an inverse ratio to the quan- 

 tity of fibrin. No constant difference in the quantity of 

 albumen in the sexes has been established. The quantity is 

 greater in the well-nourished and vigorous, than in anemic 

 and feeble subjects. 



Albumen is found in the organism at all periods of life, 

 existing even in the ovum. 



In ultimate composition albumen has been found by 

 chemists to differ very little, if at all, from fibrin. Like the 

 other principles of this class, the proportions of its ultimate 

 elements are indefinite. 



Albumen may be extracted from the fluids in which it is 

 contained by simple coagulation. The most convenient 

 method of separating it is to add to the liquid a quantity of 

 absolute alcohol, and immediately filter. In operating upon 

 the serum, we have found that about twice its volume of 

 alcohol will coagulate all the albumen. It may then be 

 collected on a filter, and its weight will represent the propor- 

 tion of this principle in its natural condition. 



Like fibrin, albumen is naturally fluid, and in this con- 

 dition and this condition only forms the important organic 

 principle of the fluids in which it is contained. 



Properties of Albumen. Liquid albumen has certain 

 properties which serve to distinguish it from other principles 

 of the same class. In a neutral mixture it is coagulated com- 

 pletely by a temperature of 167 Fahr. The same result fol- 

 lows the addition of the strong mineral acids, alcohol, and some 

 of the metallic salts. It is distinguished from caseine by 

 the fact that it is not coagulated by the vegetable acids. 

 Coagulated albumen is a grayish- white substance, always com- 

 bined with inorganic matter, which cannot be separated with- 

 out incineration, insoluble in water, but soluble in a weak solu- 

 tion of a caustic alkali. In an alkaline solution it is no longer 

 coagulable by heat. Becquerel has found that albumen has 



