CHAPTER X. 



ON THE USE OF THE LYMPHATIC SYSTEM. 



THIS system in all animals, we have found, consists of a 

 trunk or thoracic duct, and of two extremities, namely, the 

 lacteals and the lymphatic vessels. The lacteals can be traced 

 from the thoracic duct to the intestines, through the coats of 

 which they pass, and open into their cavities by patulous ori- 

 fices (LXXXIII), in order to absorb the chyle and to transmit it 

 through the thoracic duct to the blood-vessels. That this is 

 their use has never been questioned since the first discovery of 

 those vessels, from its always admitting of easy demonstration, 

 that is, by giving an animal milk, and then opening him a few 

 hours after, in which case the same fluid that is seen in his 

 intestines can likewise be seen to have got into his lacteals 

 a satisfactory proof of the lacteals beginning from the in- 

 testines. 



(LXXXIII.) Before Hewson's time, it was a popular opinion 3 that the 

 lacteals begin by open mouths in the villi of the intestines, and this view 

 continued to be generally entertained until lately. Mr. Sheldon, b after 

 stating that these mouths were discovered by Liberkuhn, declared that 

 "the ampullulae, with their orifices, are to be considered as the begin- 

 nings of the lacteal vessels." Mr. Cruikshank c figured what he con- 

 ceived to be these orifices. But Professor Miiller d found that mercury 

 injected into the lacteals does not escape from the surface of the mu- 

 cous membrane of the gut, and therefore he concluded, with Rudolphi, 

 that the villi are not perforated at their extremity. In short, it is now 

 well known that the radical extremities of the lacteals form loops, or 

 closed passages in the villi. See Mr. John Goodsir's paper on the Struc- 

 ture of the Intestinal Villi, 'Edin. New Phil. Journal,' xxxiii, 1 65 ; Henle, 

 'Anat. Gen.' tr. par Jourdan, t. i, 455 ; Mr. Paget's Report, 'Brit, and 

 For. Med. Rev.' xiv, 290 ; and Dr. Carpenter's < Human Physiology,' 

 pp. 372-3. 



a Arbuthnot on Aliments, pp.17, 20, 8vo, c Anatomy of the Absorbing Vessels of 

 Lond. 1731. the Human Body, plate 2, fig. 3,4to, 



b History of the Absorbent System, pp. Lond. 1786. 



32-8, 4to, Lond. 1784. d Physiology, tr. by Dr. Baly, i, 266, 



8vo, Lond. 1838, 1st edition. 



