2 PROPERTIES OF 



it is therefore supposed useful to attend to the proportions of 

 these parts in many disorders, and even to take indications of 

 cure from them, it has been an object with those who have 

 made experiments on the blood, to determine the circumstances 

 on which its more perfect separation into these two parts de- 

 pends ; it being obvious, that till this be done, our inferences 

 from their proportions will be liable to considerable fallacies. 

 Two of the latest writers on this subject agree, that if the 

 blood, after being taken from a vein, be set in a cold place, 

 it will not easily separate, and that a moderate warmth is ne- 

 cessary : this is a fact that is evinced by daily experience. 



clearly shown that, in animals blooded to death, the specific gravity of 

 the blood which flows last is diminished, and that there is not a greater 

 difference in the specific gravity of the whole mass of such blood than 

 in the serum alone ; whence he infers that the watery part is increased 

 in the blood which flows last. After bleeding a man into two basins, 

 I have several times found the serum of the last drawn blood speci- 

 fically lightest. 



Dr. Davy's observations' 1 seem to show that in acute inflammatory 

 diseases the blood differs very little in specific gravity from healthy 

 blood, while in chronic diseases it is comparatively dilute and of low 

 specific gravity. And although he infers from his first table that the 

 proportion of animal matter is increased, and the proportion of water 

 diminished, still the details of his last table rather favour the conclu- 

 sion that there is no constant relation between the presence of the buffy 

 coat and the proportion of fibrin in the blood. But the old opinion of 

 Quesnay, 6 Gaubius/ and Hey, g that the fibrin is increased in the blood 

 during inflammation, has been confirmed by Thackrah, h and adopted 

 by Dr. Benj. Babington,' Mr, Grainger, J and by later writers generally. 

 Mr. Wharton Jones k and Dr. Simon observe, that there is also a dimi- 

 nution of the red corpuscles, which they believe are more quickly 

 turned into fibrin 1 during inflammation than in health ; as was also the 

 opinion of Quesnay and Bordenave, referred to, as well as the some- 

 what similar notion of Sydenham, in the Introduction. 



Consult, for further details on the relative proportion of the three parts 

 of the blood in disease, M. Adral's 'Essai d'Hematologie Pathologique,* 

 8vo, Paris, 1 843 ; the observations of Becquerel, Rodier, Simon, Marchand, 

 Nasse, Enderlin, and others, given in the English version of Simon's 

 * Animal Chemistry,' published in 1845, by the Sydenham Society. 



d Res. Phys. andAnat. ii, 31,34,39, 42. Blood, new ed. by Wright, p. 206-11, 



e Traite de la Saignee, p. 415, 8vo, Paris, 8vo, Lond. 1834. 



1750. > Cyclopaedia of Anatomy, i, 420. 



f Instit. Pathol. 366-7, 8vo, Leid. Bat. J Elements of General Anatomy, p. 41, 



1763. 8vo. Lond. 1829. 



e Obs. on the Blood, p. 21, 8vo, Lond. k Report, 19,20, 21,34,35, Brit, and 



1779. For. Med. Rev. No. xxxv. 



h Inquiry into the Nature, &c. of the ' See Notes xvm & cxvin, and Introd. 



