296 THE BLOOD. [CHAP. XXVII. 



probably in a great degree due to the disproportion between the 

 red particles and the fibrine. 



Although the phenomenon of cupping and buffing frequently 

 occurs in that state which is called inflammatory, it is not so 

 exclusively confined to it as to justify practitioners in regarding 

 it, as is too often done, as a proof of the existence of inflam- 

 mation, sufficient of itself to warrant or call for further depletory 

 measures. 



III. The Physical Analysis of the Blood. By physical analysis, 

 we find in the blood the following parts ; viz., the serum ; the 

 fibrine held in solution in the serum prior to coagulation ; the red 

 corpuscles, and the colourless corpuscles, both of which float in the 

 Liquor Sanguinis. 



The Serum is a straw-coloured fluid of Sp. Gr. 1025 to 1030. 

 When heated to 165, it becomes nearly solid, proving that it 

 holds in solution a very large quantity of albumen, as much as seven 

 or eight parts per cent. In twelve ounces of serum, there would, 

 therefore, be nearly one ounce of albumen, equal to the white of 

 one egg. But this is not the only ingredient which we find dis- 

 solved in the serum. It is an alkaline fluid, and its alkalinity is 

 chiefly due to the presence of free soda, and of carbonate of soda. 

 Besides these, it contains chloride of sodium, phosphate of lime 

 and of magnesia, and probably lactate of soda. 



The serum also contains a small quantity of fatty matter, in 

 which can be detected the crystallisable as well as the oily portion. 

 In health, the proportion of this does not exceed half a part in 1000 

 parts, so that a pint of serum will contain about five grains of fatty 

 matter ; but, in some cases, it exists in so large a proportion as to 

 render the serum milky. This occurs not only in certain forms of 

 disease, but likewise, according to Drs. Buchanan and R. D. Thom- 

 son,* very shortly after the ingestion of food of an oily or amylaceous 

 nature. 



Whatever other elements may exist in the blood, as serving to 

 furnish materials for the various secretions, are held in suspension or 

 solution by the water of the serum. Thus, urea is sometimes found 

 in it ; and the recent observations of Bernard, referred to at p. 261, 

 show that it constantly contains sugar : when the liver acts imper- 

 fectly, some of the elements of bile are found in it. 



It is as yet uncertain whether the existence of even minute 

 quantities of some of these substances in the blood, such as urea, 

 and the biliary matters, is consistent with health. It is not 

 * Med. Gaz. vol. xxxvi., p. 972. 



