xxxvi INTRODUCTION. 



Dr. Davies seems to claim for himself the discovery of the 

 gluten, ignorant perhaps, like some of his successors, of the facts 

 ascertained by the earlier observers. Discussing the sources 

 of error in Jurin's estimate of the weight of the red corpuscles, 

 Dr. Davies says, "These objections could not occur to Dr. Jurin, 

 because the gluten had not been discovered as a constituent 

 part of the blood. So many errors therefore are detected and 

 removed in consequence of this one discovery" (pp. 15-16) ; and 

 mentioning, towards the end of his Essay, the want of success 

 before made in these studies, he adds, "One difficulty at least is 

 hereby removed, in the manifest exhibition of the three distinct 

 portions of the blood." (p. 51.) 



Dr. William Hunter 1 at the end of the year 1759 was well 

 acquainted with these portions, especially distinguishing the 

 spontaneously coagulable principle, which, like Borelli and 

 Davies, he termed gluten, but asserted that it was " formerly 

 falsely called fibrous." The word gluten was often used for the 

 same part still later, as by William Hunter's pupil, Dr. Hugh 

 Smith, 2 who had a similar knowledge of the blood, by the re- 

 viewer 3 of Mr. Key's work, and by Dr. Henry. 4 There is no 

 evidence that Dr. Hunter's knowledge of the properties of the 

 gluten was of an earlier period than that above noted, and 

 it is the exact date afterwards mentioned incidentally by him- 

 self. 5 Two years before, while carefully describing the con- 

 tents of an aneurism, 6 he used no term which shows that he 

 was then familiar with the coagulable lymph; but says that 

 the clot, "towards its outside, was as hard and as tough as 

 a cake of glue that had been soaked in cold water, and of a 

 cineritious complexion; towards its inside, it was more tender 

 and of a redder colour. The laminae of which it was com- 

 posed were thin as paper, regular, and did not readily separate 

 from each other, especially in the tougher external part of 



1 Anatomical, Physiological," and Chirurgical Lectures, p. 4, 4to, MS. 1759, in the 

 Library of the Royal Medical and Chirurgical Society, London, Press mark B, i, 17. 



2 Essay son the Nature and Circulation of the Blood, pp. 12, 18, 12mo, London, 1761. 



3 In the Medical and Philosophical Commentaries, by a Society in Edinburgh, 

 vol. vi, p. 380, 8vo, London, 1779. 



4 Epitome of Chemistry, p. 125, 12mo, London, 1801. 



5 Medical Commentaries, Part I, pp. 39, 41, 4to, London, 1762. 



6 Medical Observations and Inquiries, by a Society of Physicians in London, vol. 

 i, pp. 347, 348, 8vo, London, 1757. 



