CHYLIFEROUS APPARATUS. 



641 



nate; and the chyliferous vessels traverse Fig. 253. 



them in their course from the intestine to the 

 thoracic duct. Their substance is of a pale rosy 

 colour; and their consistence moderate. By 

 pressure, a transparent and inodorous fluid 

 can be forced from them; which has never been 

 examined chemically. Anatomists differ with 

 regard to their structure. According to some, 

 they consist of a pellet of chyliferous ves- 

 sels, folded a thousand times upon each other; 

 subdividing and anastomosing almost ad 

 infinitum; united by areolar tissue, and 

 receiving a number of bloodvessels. In 

 the opinion of others, again, cells exist in 

 their interior, into which the afferent chy- 

 liferous vessels open ; and whence the effe- 

 rent set out. These are filled with a milky 

 fluid, carried thither by the lacteals or ex- 

 haled by the bloodvessels. Notwithstand- 

 ing the labours of Nuck, 1 Hewson, Aber- 

 nethy, Mascagni, Cruikshank, Haller, 2 

 Bclard, 3 and other distinguished anato- 

 mists, the texture of these, as well as of the 

 lymphatic glands or ganglions in general, is 

 not demonstrated. The chyliferous and san- 

 guiferous vessels become extremely minute 

 in their substance ; and the communication 

 between the afferent and efferent vessels is 

 very easy; as mercurial injections pass 

 readily from the one to the other. Accord- Thoracic Duct. 



1. Arch of aorta. 2. Thoracic aorta. 3. Abdominal aorta; showing, its principal branches divided 

 near their origin. 4. Arteria innominata, divided into right carotid and right subclavian arteries. 5. 

 Left carotid. 6. Left subclavian. ,7. Superior cava, formed by the union of 8, the two venae inno- 

 minatae; and these by the junction 9 of internal jugular and subclavian vein at each side. 10. Greater 

 vena azygos. 11. Termination of the lesser in greater vena azygos. 12. Receptaculum chyli ; seve- 



ral lymphatic trunks are seen opening into it. 13. Thoracic duct, dividing opposite middle of dors 

 vertebrae into two branches which soon reunite ; course of duct behind arch of aorta and left subcla- 

 vian artery is shown by a dotted line. 14. The duct making its turn at root of the neck and receiving 

 several lymphatic trunks previously to terminating in posterior aspect of junction of internal jugular 

 and subclavian vein. 15. Termination of trunk of ductus lymphaticus dexter. 



ing to Mr. Goodsir, the absorbent vessels within the chyliferous and 

 lymphatic glands lay aside all but their internal coat ; and the epi- 

 thelium, instead of forming a thin lining of flat transparent scales, as 

 in the extra-glandular lymphatics, acquires an opaque granular aspect, 

 and is converted into a thick irregular layer of spherical nucleated 

 corpuscles, measuring on an average s^^th part of an inch in dia- 

 meter, so as to suggest the idea of lymph or chyle corpuscles generated 

 on the internal membrane after the ordinary manner of epithelium 

 cells, and about to be thrown off into the vessel. This layer, according 

 to Mr. Goodsir, is thickest in those lymphatics that are situated towards 



1 Adenologia, Lugd. Bat., 1696. 

 3 Addit. a Bichat, p. 128, Paris, 1821. 

 VOL. I. 41 



2 Element. Physiol., lib. ii. 3, Lausar., 1757. 



