14 PROPERTIES OF 



known amongst those whose who prepare the blood of cattle 

 for food ; for it has long been a practice with such people, to 

 receive it into a vessel containing some common salt, and to 

 agitate it as fast as it falls, by which means the coagulation is 

 prevented, and the blood remains so fluid as to pass through a 

 strainer, without leaving any coagulum behind : by this means 

 they have an opportunity of mixing it with other substances 

 for culinary purposes. 



Although the coagulable lymph so readily becomes solid 

 when exposed to the air, yet whilst circulating it is far from 

 that consistence: it has indeed been supposed to be fibrous (vin), 

 even whilst moving in the blood-vessels, but erroneously. 



(vin.) It was a question in Haller's time and before, whether the 

 coagulable lymph be fibrous in the circulating blood. a And, notwith- 

 standing the evidence to the contrary, referred to in the Introduction, 

 Dr. Buchanan b has lately published some interesting observations, to 

 show that the fibrin is not dissolved in the animal fluids, " but exists, 

 while yet within the body, already solidified, and organized in the form 

 of granules and vesicles ; and that the process of coagulation consists 

 simply in the aggregation of these minute granules and vesicles into a 

 mass visible to the naked eye." Unquestionably, minute molecules and 

 pale primary cells which floated in the fluid blood, are included in the 

 fibrinous clot ; but the delicate fibrils, which I have depicted as con- 

 stituting the bulk of such clots, do not appear to be formed of particles 

 before visible by the aid of the microscope in fluid blood, or in the 

 liquor sanguinis apart from the red corpuscles. Besides, similar fibrils 

 may be instantly produced by chemical action in certain fluids. d In 

 the clot spontaneously formed in a mixture of two varieties of perfectly 

 transparent serum, mentioned in Notes xvui and cxvin, I have dis- 

 tinctly seen the fibrils ; whilst they were not visible in the stiff, homo- 

 geneous, hyaline coagulum, formed after adding water to a fluid mix- 

 ture of a neutral salt and coagulable lymph, unless occasionally when 

 the mixture had been much more diluted before coagulation. 



What is the proof that the fibrils of fibrin may not be the primordial 

 ones of some animal textures ? And, as mentioned more fully in the 

 f Philosophical Magazine' cited below, c I know not how this setting 

 of fibrin into fibrils can be reconciled with M. Schwann's theory, 6 that 

 all fibres arise from a transformation of cells ; or with Dr. Martin 

 Barry's/ that the origin of the fibrils is from the interior of the blood- 



a Elem. Phys. torn, ii, 68-70 ; Senac, Edin. Med. and Surg. Journ. vol. Ix, 



Traite du Coeur, ed. 1749, ii, 102-3. p. 161 ; and Mr. Addison, Trans. 



b Proc. Glasgow Phil. Soc. No. 7. Prov. Med. and Surg. Ass. vol. xii, 



c Gerber's Anat. 8vo, Lond. 1842, pi. 28 ; 249-50. 



and Lond. & Edin. Phil. Mag. S. 3, e Wagner's Physiol. tr. by Dr. Willis, 



vol. xxi, 1842, pp. 242-4. p. 222. 



d Gruby, Morphologia Fluidorum, 8vo, f Phil. Trans. 1842, p. 90. 



Vindobonae, 1840, tab. 5, fig. 83; 



