xxxii INTRODUCTION. 



Senac 1 described the whitish substance which congeals of 

 itself, becomes tenacious, and forms the buffy coat of the blood. 2 

 He terms the pale part indifferently a white oil, lymphatic 

 matter, white or whitish substance, and coagulated lymph, 3 but 

 never coagulable lymph. He correctly explained the formation 

 of the buffy coat ; 4 and separated the lymph, by washing, from 

 the blood-clot, as Malpighi had done, and from fluid blood by 

 whipping it with twigs, after the method of Ruysch, observing 

 that the latter operation hinders coagulation by removing the 

 concreting principle or bond of the other parts of the blood, 

 and that the red part alone cannot unite into a compact sub- 

 stance; though he also speaks of the coagulation of the red 

 globules, 5 yet not without combating the errors of Leeuwenhoek. 6 

 He observed that the lymph forms clots separate from the red 

 corpuscles in aneurisms ; that it closes the ends of the great 

 blood-vessels after amputations, 7 and that it differs from the 

 white of egg and from serum in the property of coagulating 

 spontaneously. 8 After stating that the red particles may be 

 dissolved and become white, 9 he gave reasons for objecting to 

 the opinion of some writers, perhaps alluding to Sydenham 

 and Quesnay, that the white part of the blood is formed of the 

 red, deprived of its colouring matter. 10 



Examining the lymph microscopically, Senac found no glo- 

 bules in it, but merely branches or irregularly connected 

 molecules, the concretion resembling what is observed in a 

 plate of scarf-skin. 11 He correctly states, that the coagulated 

 lymph forms a kind of membrane, like a true reticular tissue, 

 but incorrectly ascribes the net-like appearance to other fluids 

 coagulating with the lymph, and visible with the aid of the 

 solar microscope. 13 



1 Traite de la Structure du Coeur, 4to, Paris, 1749; and 2d edit. 4to, Paris, 1774, 

 which appeared also in 1783, with a new title-page only. 



2 Ed. 1749, torn, ii, p. 91 ; and 2d edit. torn, ii, p. 284. 



3 Ed. 1749, torn, ii, pp. 91, 449, 453, 75, 96. 



4 Ed. 1749, torn, ii, pp. 90, 92, 124, 447 ; and 2d edit. torn, ii, pp. 285, 299, 414. 



5 Ed. 1749, torn, ii, pp. 92-3, 447-49, 129. 



8 Ed. 1749, torn, ii, pp. 659, 91. 7 Ed. 1749, torn, ii, p. 94. 



8 Ed. 1749, torn, ii, p. 95. 9 Ed. 1749, torn, ii, p. 450. 



10 Second edit. pp. 413-14. 



11 Ed. 1749, torn, ii, p. 660 ; and 2d edit. torn, ii, p. 280. 



12 Ed. 1749, torn, ii, pp. 92, 449, 452 ; and 2d edit. torn, ii, pp. 285, 415. 



