Dr. Spurgin on the Nature and Properties of the Blood. 371 

 ters, the celebrated chemist Berzelius was led to contend that 

 there was very little difference between these two products, 

 albumen and fibrin. 



The only character that appears to distinguish one from 

 the other, is, that whilst albumen requires a high temperature 

 <br its coagulation, the fibrin will coagulate spontaneously at 

 a low one. Berzelius states the composition of the serum to 

 be 905 narts water; 80 albumen ; substances soluble in alco- 

 hol, such as the muriates of potass and soda, 6 parts ; lactate of 

 soda and animal matter, 4 parts; and substances soluble m 

 water onlv,-such as soda, phosphate ot soda, and a little ani- 

 mal matter,-5 parts. In this statement of the composition of 

 the serum, nothing is said of the existence of sulphur in any 

 of its forms or modifications: but other chemists have given 

 such proofs of its existence in the serum of the blood, as to 

 render it beyond all doubt. Alcohol, metallic salts and tan, 

 will also cause its coagulation ; and the same change, accord- 

 ino- to the discovery of Mr. Brande, may be effected by the 

 negative wire of the voltaic electric circle. 



Dr Bostock is of opinion that some of these agents in the 

 coagulation of the serum, as alcohol, and perhaps the stronger 

 mineral acids, produce their effect by abstracting a portion of 

 the water which held the albumen in solution : while tan and 

 the metallic salts unite with die albumen and iorm a com- 

 pound which is insoluble in water, and consequently separates 

 from the fluid; thus producing an effect, which should rather 

 be styled ,,recipitation than coagulation *. XVhen serum is co- 

 agulated, it exactly resembles the white of the egg hardened 

 b? boiling; and it "is found to be essentially the same with this 

 substance^ whence it has obtained the name of albumen. The 

 efficient cause of this coagulation is a question that has been 

 frequendv discussed f, and the only way it can be accounted 

 for, is, by supposing some change to take place m the figure or 

 nature of its particles, by which their relation to each other is 

 altered; but what the nature of this new relation is, or the 

 means by which it is effected, has not been explained. Con- 

 centrated sulphuric acid coagulates albumen ; but it assisted 

 by a moderate heat dissolves it again and forms a sohition 

 of a very fine red colour. Several hypotheses have been 

 framed to account for this remarkable change ; but the abstract 

 conch.sion just now stated, cannot be disputed. Betore coa- 

 gulation, serum is readily miscible with, or soluble in water ; 

 but alter coagulation it is completely insoluble. A most re- 

 markable effect t^ikes place after digesting coagulated albumen 

 for some time in diluted nitric acid ; for it is hereby converted 

 • Bostock's Elements of Physiology, vol. i. pp. 408. 409. f Ibid. p. 470. 

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