ORIGIN OF THE ABSORBENT VESSELS. 337 



from these facts is, that those vessels originate by open orifices 

 on the surfaces of the heart and foot. 



Origin of the Absorbent Vessels. 



Mascagni, who devoted the greater part of his life to the 

 study of the absorbent vessels, was able to demonstrate their 

 existence in every part of the body, with the exception of the 

 substance of the brain, the spinal marrow, the eye, bones, 

 placenta, and umbilical cord. Within a recent period Fohman* 

 has succeeded in detecting them on the surface of the enceph- 

 alon, in the meninges, in the plexus choroides, in the pla- 

 centa, and in the umbilical cord ; Arnoldf has seen them upon 

 many of the tissues of the globe of the eye ; and Cruikshank, 

 Soemmering, and Bonamy,J have succeeded in tracing them 

 into the interior of the bones. There can, therefore, at the 

 present moment, be no doubt of their general distribution 

 throughout the body. 



On the surfaces of the different membranes of the body, these 

 vessels have, however, been found to be most numerous ; and 

 Mascagni was induced to believe that these membranes, and 

 especially the serous and the cellular, the latter of which forms 

 the web-work of the whole body, consisted of a net-work of 

 absorbent vessels. But he does not explain himself clearly in 

 regard to the point in question, viz. the mode in which these 

 vessels have their origin. 



The great difficulty in determining this question in man and 

 the superior animals, is the obstacle which the valves present 

 to the injection of mercury backwards and towards their roots ; 

 for if this could be effected, as it has been in the excretory 

 ducts of the glands, the anatomist, by the aid of the microscope, 

 would probably soon be enabled to solve the difficulty, and 

 especially, as there is reason to believe that the radical absorb- 

 ents have a diameter superior to that of the sanguineous capil- 



* Memoires sur les Vaisseaux Lymphat. etc., etc. Liege, 1833 ; and, Sur les 

 Vaisseaux Absorb, du Placenta et du Cord Umbilicale. 



f Anatomische and Physiol. Untersuchungen uber das Auge des Menschen. 

 Heidelburg, 1832. 



| Cruvielhier Anat. Spec. T. iii. 

 VOL. ii. 29 



