VOL. LXX.] PHILOSOPHICAL TRANSACTIONS. fiS? 



The preparation of the thoracic duct was at first put up in spirits to preserve 

 its original appearance, and in this state Mr. C. took it with him to London. 

 On showing it there to several anatomical gentlemen, they were in doubt whe- 

 ther there might not be yet remaining some small cavity in the duct, and were 

 therefore desirous he should take the preparation out of the spirits to be examined 

 more accurately. This he readily complied with, and it was accordingly examined 

 very circumstantially by Dr. Hunter, Mr. Watson, Mr. J. Hunter, and Mr. 

 Cruikshanks. The appearances which these gentlemen particularly noticed were, 

 that the duct was completely filled up, excepting at the lower bulbous pari, 

 commonly called the receptaculum chyli, where, indeed, there was room enough 

 for air to pass between the coat of the duct and tlie adventitious substance 

 within it ; so that the receptacle, which before appeared flat, on throwing in air 

 became rounded and fully distended: but this air was totally confined to the re- 

 ceptacle, and could not be forced up the duct in the smallest degree. The 

 receptacle was then slit open, and an attempt made to pass a bristle up the duct, 

 but this was found impossible. Mr. Cruikshanks afterwards endeavoured to 

 force mercury up the duct, but not the smallest particle would pass. 

 > From these different examinations, (says Mr. C), we were all thoroughly 

 convinced, that the receptaculum chyli was not so completely filled up but that 

 it might receive a small quantity of fluid, yet the duct itself was totally imper- 

 vious, without a possibility of admitting any. The coats of the duct did not 

 appear to have undergone any morbid change: for in some places, where the 

 substance it contained was not so strongly attached but that the coat would admit 

 of being raised from it, they were found in a perfect natural condition. At 

 other places, where the attachment was inseparable, there was a greater appear- 

 ance of ossification externally; but this we were convinced arose merely from the 

 thinness of the coats in that part, where the receptaculum chyli was laid open ; 

 the substance within it appeared of a membranous nature very similar to that 

 found in the vena cava of this same subject, but more laminated. We presumed, 

 that the same kind of membrane had been continued through the whole of the 

 duct, but was now become pretty completely ossified in all that portion of the 

 duct which we were in possession of. A small body, resembling a lymphatic 

 gland on the side of the upper part of the duct, was opened by Mr. J. Hunter, 

 who found the same ossific disposition in this little body, as we before noticed 

 in the duct itself. 



We next examined the substance that partly filled up the vena cava. It was in 

 length about 4 inches; at the upper end, broad and conical, at the lower, much 

 narrower and rather rounded. Its surface appeared irregular and granulated with 

 small bony particles. It appeared flattened, perhaps from the pressure of the 

 blood constantly moving over it; for having made a small opening with a lancer 



