18 Dr, John Mulleins Examination of [July 



soda. Hence, the propriety of administering large and 

 frequent doses of the carbonates to patients labouring under 

 cholera, as these can be taken internally without producing 

 the caustic effects of the pure alkalies. 



BUFFY COAT. 



In inflammation, the blood, when solidifying, presents a 

 different appearance from healthy blood ; for before it has 

 coagulated the red globules of the blood sink under the sur- 

 face of the fluid, so that the liquid portion appears scarcely 

 red, and often colourless or white, previous to coagulation. 

 Then it forms into a gelatinous mass, which is slightly red, 

 often white, or greyish yellow. The yellowish upper portion 

 of the cake has a smaller diameter than the under portion, 

 although at first the cake possessed a diameter equal to the 

 vessel. The cause appears to be that in inflamed blood the 

 red globules sink before coagulation, while in healthy 

 blood they do not descend till that period, and have the 

 fibrin diffused through the whole mass of blood ; but the 

 under portion of the coagulum contains the red globules ; 

 the upper part is destitute of them, and is termed crusta in- 

 flammatoria, or buffy coat. 



Even before coagulation, one can tell whether there will 

 be a buffy coat or not; when the upper portion of the 

 liquid becomes first transparent and then whitish. 



Babbington has observed, {Med. Chirurg. Trans, xvi. ii.) 

 that this colourless serum, before the coagulation, can be 

 skimmed off with a spoon, and that this serum coagulates. 

 Miiller has noticed this in the blood of a pregnant woman. 

 The serum of inflamed blood is not lighter than that of 

 healthy blood; and Miiller has noticed that when the 

 serum of strained blood, is mixed with a solution of common 

 salt, specifically lighter than the serum, the globules do 

 not sink further under the surface. Hewson's idea of the 

 cause of the buffy coat was, that as the inflammatory blood 

 is longer of coagulating than healthy blood, so the red 

 globules of the former have ample time to sink beneath the 

 surface before coagulation takes place. In experimenting 

 with the view of determining the propriety of this notion, 

 Miiller noticed in the blood of cats and men, the globules 

 sink in a quarter of an hour, one line ; and he remarked, 



