INTRODUCTION. xxxv 



the pleuritic coat to an undue tenacity of the fibre, connected 

 with an increase of its quantity in proportion to the serum, 

 and with a condensation of the serum into the fibre. He 

 regarded the constitution of blood and milk as so nearly alike, 

 that the one might be called red milk, and the other white 

 blood ; comparing the serum of blood to whey, the red part to 

 cream, the fibre to curd, and the red corpuscles to oily globules 

 like those of milk. 



Dr. Richard Davies 1 observed that the inflammatory pellicle 

 is formed by the coagulation of a fluid, a gluten natural to the 

 blood, rising to the surface, and exactly similar to the con- 

 creted substance obtained from the blood by stirring it with a 

 tube. He washed the crassamen, as he calls it, with water, and 

 described the remaining gluten as resembling a congeries of 

 pellucid membranes and fibres (pp. 5-9), expressly declaring, in 

 opposition to Jurin, that the red globules do not possess any 

 strong cohesion to form a mass or compact body, without the 

 interposition of the gluten, (pp. 11, 12.) This, Davies adds, ac- 

 quiring tenacity by cold and rest, causes coagulation ; and then 

 by its concreting force, presses out the serum, so that " the 

 denser the texture of the gluten is, the more serum it presses 

 out ;" and when no serum separates from the blood, it usually 

 remains a tender coagulum, not from a defect of serum, for 

 then the coagulum would be dense, but from the weakened 

 contraction of the glutinous parts, (pp. 15-19.) 



The inflammatory pellicle he ascribed, as Quesnay before, 

 and Hewson afterwards did, to a preternatural attenuation or 

 fluidity of the gluten, permitting the red globules to subside 

 while it rises with the serum to the surface. Here the gluten 

 exerting its full cohesive force, becomes a firm membrane, or 

 more compact body than that part of the clot which has its 

 cohesion broken by the intervention of the red globules. Thus 

 the gluten squeezes out the serum and compels the crassamen 

 into a more regular form. (pp. 23-24.) He fixes the specific 

 gravity (p. 13) of the serum at 1-026, of the pellicle of inflamed 

 blood, as he terms the bufiy coat, at 1-056, and of the crassamen 

 at 1-084, adopting Jurin's estimate, with some reservation, of 

 the red globules at 1-126. 



1 Essays to promote the Experimental Analysis of the Human Blood, by Richard 

 Davies, M.D., late Fellow of Queen's College in Cambridge, 8vo, Bath, 1/60. 



