1868.] Vrof.W. Jones on the propulsion of Lymph ^c. 335 



have assumed nearly their final positions with respect to the base of the 

 heart, and the aperture of communication between the arterial infundibula 

 is nearly closed up. 



17. After the complete separation of the aortic and pulmonary infun- 

 dibula from each other, the further changes in the semilunar valves consist 

 principally in increase in size and diminution in thickness, so that they 

 become more and more membranous, pari passu, with the growth of the 

 other parts of the heart. 



In the description given above of the division of the truncus arteriosus, 

 it has been shown that the aperture in the septum of the ventricles does 

 not close up entirely as is com.monly supposed, but finally developes into 

 the aortic infundibula. 



The fifth vascular arch on each side gives off the branch to the hmg 

 of that side, and becomes ultimately the corresponding branch of the 

 pulmonary artery, according to the view long ago propounded by Yon 

 Baer. 



In conclusion I must thank several kind friends for assistance received 

 from them during the preparation of this paper, which I here beg leave 

 to acknowledge. In particular Dr. Beale, who has given me much 

 valuable advice throughout ; the Rev. George Kempson and my cousin 

 Mr. Charles Paddison, who sent me abundant supplies of fresh eggs ; and 

 Dr. Cayley, who kindly revised the translations from the German authors 

 referred to. 



II. On the Phenomena observed to attend the propulsion of Lymph 

 from one of the Lymphatic Hearts into a Vein in the Frog." By 

 Thomas Wharton Jones, P. U.S., Professor of Ophthalmic 

 Medicine and Surgery in University College^ &c. Received 

 March 28, 1868. 



(Abstract.) 



An ansemic frog, killed, as regards sensation and voluntary motion, 

 without stoppage of the circulation, by plunging into water at 110° or 

 120° Fahr., was laid open, and the posterior part of the anterior lymphatic 

 heart of one side, in the niche behind and below the extremity of the large 

 transverse process of the third vertebra, brought into view. By the removal 

 of the skin of the back from over the scapular region, the part of the heart 

 mentioned admitted of examination by transmitted Hght under a simple 

 microscope — the lens ^-inch focus. It was seen that when the lymphatic 

 heart contracted, a stream of lymph was propelled from it into a vein at its 

 posterior border, and swept before it the blood in that vessel, whilst the 

 flow from behind was arrested. As soon, however, as diastole of the 

 lymphatic heart supervened, the flow of blood from behind became re- 



