178 



CIRCULATORY SYSTEM. 



presence of albumen. Mr. Brande considers this liquid albumen " 

 as an albuminate of soda, with an excess of its base, and that 

 its fluidity depends on the excess of soda; when, therefore, the 

 latter is removed / or neutralized by an acid, the albumen co- 

 agulates. Under the action of the Galvanic pile, like the in- 

 fluence of heat, the soda produces mucus, by blending with a 

 part of the albumen; and the remainder of the latter, not being 

 able to retain its fluidity after the abduction of the soda, co- 

 agulates. 



This mucus is, probably, the part which Mr. Hunter speaks 

 of as retaining its fluidity when other portions of the serum are 

 coagulated by heat. It is observed in meat either roasted or 

 boiled, and 'comes from it as a thin, limpid fluid, somewhat 

 tinged with the red globules. The older the animal is, the 

 greater is its comparative quantity: in lamb, there is scarcely 

 any of it, whereas, in mutton five or six years old, it is abun- 

 dant; the same rule seems to hold in regard to the human sub- 

 ject. This serosity, or mucus, is coagulable by Goulard's 

 Extract.* 



The serum is not always transparent, but sometimes wheyish 

 and thin: when it settles, it often throws up a white scum like 

 cream. This more frequently occurs in pregnant women, 

 though it is not confined exclusively to either sex, or to any 

 known condition of body. The specific gravity of the globules 

 composing this scum varies; for though it generally floats on 

 the surface of the serum, it does not always : it also sometimes 

 swims, and, on other occasions, sinks in water. It has been 

 erroneously considered as chyle not yet assimilated, or as ab- 

 sorbed fat or oil. It is, probably, this substance which pre- 

 sents itself under the form of microscopic globules in the co- 

 agulum of serum; and, when serum has been kept for several 

 days, is de-posited in the form of globules at its bottom. These 

 globules present a singular motion of ascent and descent in the 

 serum; upon the application of heat to it by holding it in the 

 hand. It is said that albumen, coagulated, presents a very 

 close resemblance to fibrine.f 



The presence of soda uncombined in the serum, is readily 

 ascertained by an infusion of red. cabbage, (Brassica oleracea,) 



* Hunter, loc, cit, t Beclard, loc, cit, 



