CHAP, xxvii.] THE BUFFY COAT. 295 



only of serum and red particles. The coagulation of the fibrine of 

 the blood is one of those ultimate facts in physiology which we 

 must be content to observe and to describe, but of the cause of 

 which we are likely to remain ignorant. 



The buffing and cupping of the blood has long attracted the notice 

 of observers, and is regarded by many practical men as an indication 

 of a state of inflammation, in some part of the body, at the time of 

 the abstraction of the blood. The immediate cause of this pheno- 

 menon is explained with the highest probability, as follows, by Dr. 

 Babington : 



" The blood, consisting of liquor sanguinis, and insoluble red 

 particles, preserves its fluidity long enough to permit the red par- 

 ticles, which are of greater specific gravity, to subside through it. 

 At length, the liquor sanguinis separates by a general coagu- 

 lation into two parts, and this phenomenon takes place uniformly 

 throughout the liquor. That part of it through which the red par- 

 ticles had time to fall, furnishes a pure fibrine or buffed crust, while 

 that portion into which the red particles had descended, furnishes 

 the coloured clot." The following experiment, made by the same 

 ingenious observer, illustrates the truth of the explanation given by 

 him. " Take two similar tall jars or phials, each capable of holding 

 about four or five ounces, and let one of them be half-filled with 

 olive oil. Draw the blood of a healthy subject into each : that 

 which flows through the oil will be found to have a layer of Liquor 

 Sanguinis on its surface, which will form a buffed crust; while there 

 will be none upon that which is received in equal quantity, and 

 in other respects, under the same circumstances, into the empty 

 jar." * 



According to the observations of Nasse, and of Mr. Wharton 

 Jones, the red particles of blood which is disposed to become buffed 

 and cupped, exhibit a remarkable tendency to cohere in the form 

 of rolls, like piles of coin; and this probably facilitates their 

 precipitation to the lowest part of the coagulating mass. 



The circumstances which favour the formation of the buffy coat 

 may be any or all of the following : 1. Slowness of coagulation ; 

 2. Increased weight of red corpuscles; 3. Diminished specific 

 gravity of serum, which obviously would have a corresponding 

 effect to the preceding ; 4. A great diminution in the proportionate 

 quantity of the red corpuscles, or an increase in that of fibrine, 

 and of colourless corpuscles. The occurrence of the cupped and 

 buffed blood, after great hemorrhage, or in cases of anaemia, is very 

 * Med. Chir. Trans., and Cylop. Anat., art. Blood. 



