290 SIX.TH REPORT — 1836. 



munications for which he contended, in every subject, and the 

 care which he had taken to describe and delineate them when 

 met with seemed to indicate that they were comparatively rare, 

 even amongst his numerous examinations., Amongst the facts 

 connected with the inferior animals, the author remarked that 

 in the kangaroo he had found that the thoracic duct was double, 

 aflfording another instance of similarity between the circulation 

 in that animal and in birds, and noticed the very considerable 

 dilatation of the receptaculum chyli which he had met with in 

 a foetal pig. The Report also contained some notice of the la- 

 bours of Miiller, Arnold, Fohmann, Panizza, and Drs. Thomson 

 and Sharpey on this subject, as well as the recently published 

 thesis of Professor Brechet. In relation to the origins of the lym- 

 phatics, he noticed the fact observed by Mr. T. King, that the 

 lymphatics of the thyroid gland were found filled with the very 

 peculiar secretion proper to the cells of that organ, and that he 

 had himself seen the lymph in the thoracic duct of the pig flow- 

 ing alternately colourless and highly sanguinolent, which, as 

 no violence had been done to the abdomen, appeared to indicate 

 some natural but unexplained communication between the san- 

 guiferous and lymphatic systems. The Report concluded with 

 some observations respecting the formation of vessels, in which 

 the author endeavoured to account for the exact correspondence 

 which often exists between arteries and veins, and also for the 

 production of valves in the latter vessels and in absorbents. 



