THE BLOOD. 33 



little serum. The other vein I did not open till after the blood 

 was congealed, and then I found the upper part of the coagulum 

 whitish like the crust in pleuritic blood. 1 



And that the size is merely the coagulable lymph separated 

 by the subsidence of the red particles, will appear evident to 

 any person who will, as Sydenham (xx) directs, move a finger 

 or a teaspoon through the blood when he observes its surface 

 becoming transparent ; for in this case the blood that other- 

 wise would have been sizy, will now have a natural appearance, 

 or be without size; from the red particles being .prevented 

 from subsiding. 



It has been a very generally received opinion, that inflam- 

 mation thickens the blood, and makes it more ready to coagu- 

 late. Nay, some have gone so far as to say, that in those dis- 

 orders where the inflammatory crust is seen, the blood is almost 

 coagulated even before it is let out of the vein. Now I am 

 persuaded from experiment, that the contrary of this is true ; 

 or that inflammation, instead of increasing the disposition of 

 the blood to coagulate, really lessens it (xxi) ; and instead of 



1 This is not the only apparently healthful animal whose blood had a crust ; I have 

 seen it in others : whence I at first suspected that merely keeping the blood fluid for 

 a little time was sufficient to produce this appearance ; but I altered my opinion on 

 seeing that in the greatest number of animals it did not occur ; nor is it commonly 

 met with in the hearts of those persons who die a violent death, though the blood 

 remains longer fluid in such cases, than it does in the basin where the size appears. 



(xx.) Sydenham, Opera Omnia, ed. Soc. Sydenhamianse, 8vo, Lond. 

 1844, sect 6, cap. iii, p. 248. In this case the proportion of fibrin 

 would be the same, as the red corpuscles are only prevented from sinking 

 by stirring them with the liquor sanguinis till it becomes viscid. And 

 even then, according to M. Denis, a the separation of the corpuscles and 

 fibrin is not entirely prevented ; for he states that the buffy part is diffused 

 throughout the clot in the form of whitish granulations ; and such, too, 

 he says, is the case when the buffy coat is prevented from forming, as 

 he maintains, in blood taken away during syncope. After stirring up 

 horse's blood, just when the buffy 'coat began to form, and preventing 

 its formation, I did not find any buffy granules on the cut surfaces of 

 the clot. 



(xxi.) It has been generally supposed that the coagulation of the 

 blood in inflammation is so retarded as to cause or favour the sinking 

 of the corpuscles, and the consequent formation of the buffy coat. Mr. 



3 Essai sur le Sang, p. 287, 8vo, Paris, 1838. 



