INTRODUCTION. xxxi 



that the red portion forms no clot without the containing or 

 enveloping white lymph, and showed that the different de- 

 grees of consistency of different parts of the clot depend on 

 the proportion of the white matter, which is most solid when 

 it coagulates alone; next adding, that if it were possible for 

 the blood to be fluid until all the lymph rose to the surface, 

 this would form the only clot, while the globules and serum 

 would remain fluid. He concluded that the lymph is the only 

 part of the blood susceptible of self-coagulation. 



Quesnay 1 observed that the clot is composed of little white 

 filaments, which he called the fibrous lymph, and of red globules, 

 the lymph condensing when let out of the blood-vessels, and 

 retaining the globules in its interstices. He correctly noticed 

 and drew the right conclusions from the effects of whipping 

 fresh blood with twigs; on which point Senac's 2 knowledge was 

 afterwards less accurate. Describing the buffy coat, Quesnay 3 

 remarked that the blood is full of many glairy humours, which 

 in cooling form the crust ; that this is of the nature of lymph ; 

 and that it collects, from being in a dissolved state, on the 

 surface of the blood during inflammation, but does not so rise 

 at the beginning of the disease, before the humour has come to 

 such a state of dissolution. Hence he concluded, as Hewson 

 afterwards did from a set of ingenious experiments, I believe 4 

 incorrectly, that the floating of this humour on the blood, far 

 from showing it to be thickened, proves that its fluidity is in- 

 creased. Quesnay also stated, in anticipation of a very recent 

 doctrine, 5 and of an older and more generally admitted one, 6 

 that the humour appears to be formed from the molecules, as 

 he calls the red corpuscles, destroyed and reduced to a glaire by 

 the action of the arteries ; and that this humour abounds in 

 acute diseases, at the expense of the molecules, sometimes to 

 such an extent that the red part of the blood is much diminished. 



1 Principes de Chirurgie, pp. 31, 32, 34, 8vo, Paris, 1746. 



2 Traite du Coeur, torn, ii, p. 303, 4to, Paris, 1783. 



3 Traite de la Saignee, pp. 402, 405, 406, 415, 416, nouv. ed. 8vo, Paris, 1750. 



4 See Notes xxi, xxm, and xxix. 



5 See the observations of Mr. \Vharton Jones, and Dr. Simon, on the transforma- 

 tion of the red corpuscles into fibrine, Notes i and cxvui. 



6 See the observations of Mr. Hey and others on the increase of the fibrine in the 

 blood during inflammation, Note i. 



