282 CIRCULATORY SYSTEM. 



associated with the history of these feuds. Almost a century 

 then passed before there were many important additions to the 

 knowledge of those times. After which great contributions 

 were made by Dr. A. Munro,* Dr. W. Hunter,f Hewson,}: 

 Cruikshank, but chiefly by the celebrated Mascagni,|| who, 

 having imagined finely pointed instruments of glass for exe-* 

 cuting his injections of these vessels, succeeded in demon- 

 strating them in almost ever^ part of the body, excepting the 

 spinal marrow, the brain, the ball of the eye, and the placenta. 

 In some of these parts, however, he says he has seen them, 

 and he speaks confidently of their existence, without exception, 

 every where, even in the enamel of the teeth. IF 



The Lymphatic Vessels are small, pellucid, transparent cy- 

 lindrical tubes, generally of about a line vor less in diameter, 

 whose trunks have been traced to all the external and internal 

 surfaces of the body, and to the depth of all the organs, with 

 the exceptions staled. It is only very lately, however, that their 

 existence on the external surface of the skin has been put be- 

 yond doubt, by the observations and injections of M. Lauth.** 

 Their origin is so attenuated, that anatomists have come to no 

 satisfactory conclusion in regard to its manner. The earlier 

 cultivators of this branch of study, not knowing their absorbent 

 properties, conceived them to be continuations of the arteries 

 applied to the reconducting of the serous part of the blood to 

 the heart; and considered the opinion substantiated bv the cir- 

 cumstance of their being occasionally filled by fine injections 

 thrown into the arteries. More improved views of their uses 

 caused the abandonment of this theory, and the substitution of 

 their absorbing powers; in which case the minds of anatomists 

 became divided between the ampulla-like mouth, or wide patu- 

 lous origin of Lieberkuhn, arid the small orifices of Hewson. 

 It is, perhaps, not possible to solve the question in regard to the 



* De Vents Lymph. Valv. Berlin, 1757-70. 



t Med. Comment. London, 1762-77. 



J Experimental Inquiries, London, 1774-77. 



Anal, of the Lymphatic?,. London, 1774-90. 



i! Vasor. Lymph. Corp. Hum. Historia et Ichnographic, Siennc, 1787. 



^ Prodromo della Grande Anatomia, vol. i. p. I. 



** Essai sur les Vaisscaux Lymph, Strasburg, 1824. 



