xxiv INTRODUCTION. 



high degree interesting, not only on account of his investigation 

 of parts of the animal system before scarce known, not only on 

 account of the clear idea which his accurate descriptions and 

 elegant preparations have enabled us to form of the parts dis- 

 covered, but also that he has thereby been enabled to confirm 

 that hypothesis which had been, with great show of reason, en- 

 tertained, that the lymphatics are the only absorbent vessels. 



" He has not only discovered the existence of this system in 

 the classes of birds and fish, but he has been enabled to follow 

 the course of them (the lymphatics) to an astonishing minute- 

 ness, and proved their beautiful disposition on the intestines to 

 ocular demonstration." 1 



It was also stated by the president, that he and the council, 

 in adjudging the medal to Mr. Hewson, had considered chiefly 

 what person had, within the year 1769, " contributed most to 

 the advancement of science and useful knowledge." Hewson' s 

 papers were highly commended by many of his contemporaries, 

 especially by Dr. Hunter, 2 Mr. Sheldon, 3 and Dr, Lettsom. 4 



Hewson' s three papers on the Properties of the Blood were 

 published in the ' Philosophical Transactions' for 1770; and 

 form the first three chapters of the First Part of the ' Experi- 

 mental Inquiries/ Before the publication of the second edition, 

 in 1772, of the ' Inquiry into the Properties of the Blood/ it 

 underwent, according to Mrs. Hewson, 5 a critical examination 

 by Sir John Pringle, to whom it was afterwards dedicated. 

 The first, or duodecimo edition was published in 1771. There 

 is a third edition, merely a reprint, in 1 780, of the second. 



His observations on the Red Particles of the Blood, which 

 appeared in the f Philosophical Transactions' for 1773, were re- 

 published by Magnus Falconar in the first chapter of the Third 

 Part of the ( Experimental Inquiries/ An imperfect abstract of 

 Hewson's Observations on the Uses of the Lymphatic Glands, 

 Thy mus, and Spleen, was published, without his concurrence, in the 

 first volume of the ' Medical and Philosophical Commentaries / 6 

 and in July, 1773, he gave a short account of his views on those 



1 Journal Book of the Royal Society, fol. MS. vol. xxvii, pp. 396-9. 



2 Two Introductory Lectures to his last Course of Anatomy, p. 60, 4to, Lond. 1784. 



3 History of the Absorbent System, pp. iii, iv, 4to, London, 1784. . . 



4 Transactions of the Medical Society of London, vol.i,p. 61, 8vo, Lond. 1810. 



5 Mr. Pettigrew's Life of Dr. Lettsom, vol. i, p. 145. 



6 By a Society in Edinburgh, 8vo, London, 1773. 



