162 A Sketch of a Mis lory of Pus, 



or abscess. On that account mention is made of the trial* 

 with water and fire. Pus sinks, it is observed, in not only 

 mere water, but in salt water; while the secreted slimy sub- 

 stance of the bronchial membrane called mucus is frothy, 

 and floats on water : — the former substance is readily dif- 

 fusible through water, but the latter is not so. If pus be 

 contained in sputum, it emits a most offensive smell while 

 burning on an ignited coal. From the earliest writers it 

 appears that the judgement was regulated by observation 

 of the circumstances of the discharge of purulent matter, 

 as well as of its properties : that from suppurated tubercles 

 was distinguished from the abscesses called vomica, and em- 

 pyema by acute inflammation, such as of peripneumony 

 and pleurisy; but a third source from the lungs, now well 

 ascertained, viz. by secretion fron the bronchial membrane- 

 without any breach in its continuity or loss of its substance, 

 was made known in consequence of the observations pub- 

 lished about the same time by the learned De Haen of 

 Vienna, and by our most ingenious countrymen Mr. John 

 Hunter and Mr. Hewson. Previously to these pathologists, 

 Mr. Sharp in his Critical Essays, p. 142; and Mr. Gataker 

 mhh Essays, p. 97, as well as, I believe, other authors, had 

 asserted that puriform matter is producible without ulcer_ 

 or loss of substance or breach, by inflammation, or merely 

 by irritation occasioned by extraneous bodies in gonorrhoea, 

 ophthalmia, &c. It was, however, generally considered as 

 doubtful, whether or not this matter was the same as that 

 of ulcers and abscesses. This indecision was founded, pro- 

 bably, on prejudice rather than on any actual observation 

 of differences of properties. The proof by dissection that 

 membranous surfaces, in their entire state, produce matter 

 of the same sort as that of sores and abscesses, was hitherto 

 the most important pathological fact brought to fight sub- 

 sequently to the Greek writers. 



About 40 years ago, Simpson of St. Andrews, DeHaen, 

 Gaber, Pringle, Cullen, Fordyce, Hunter, Hewson with 

 his pupil Hendy*, were the prominent parties in the dis- 

 cussion of the point — the matter from which pus was im- 

 mediately derived. The first person who considered pus to be 

 the product of vessels becoming, or at least performing the 

 office of, glands, as far as I know, was Simpson. De Haen's 

 observations confirmed this opinion ; but the deposition of 

 an opake white matter from serum of blood on standing, 

 induced Gaber, Pringle and? Cullen to account for the pro- 



* Tentamen Inaugurate de Secretionc glandulari. Edinburgh, 1774. 



duction 



