GREAT LYMPHATIC 1Y.7.V 



645 



with the thoracic duct by voluminous collateral branches, then unite with 

 it in such a way as to be inserted together by a single orifice above the gulf 

 of the jugulars." Colin. 



Fig. 303. Fig. 30-t , 



I Hi: GREAT LYMPHATIC VEIN AND ENTRANCE OF THE THORACIC DfCT. 



A, Thoracic duct ; B, Great lymphatic vein, or right lymphatic trunk ; C, n, Anasto- 

 moses established between them near their insertion. 



DIFFERENTIAL CHARACTERS IN THE LYMPHATIC SYSTEM OF OTHER THAN SOLIPED ANIMALS. 



The lympl atic system, glands and vessels, is more developed in Ruminants and the 

 Pig than in the Carnivora. 



In this respect the domesticated animnls may be classified in the following order : 

 - ! ,eep. Horse, Pig, Dog, Cat. 



RUMINANTS. "The thoracic duct of large Ruminants, when it has entered the thorax 

 by a special opening in the diaphragm, almost distinct from that of the aortic arch, is 

 placed al>ove and to the right of the aorta, between it and the spine. There, although; 

 outrfide the porresj>onding intercostal arteries, it is completely concealed by a thick layer 

 of adipose tissue, in which are numerous subdor^al glands. Towards the fifth di>al 

 \vrtebra, it receives a large lymphatic vessel coming from the enormous gland that exists 

 on the track of the oesophagus in the posterior mediastinum; it then crosses the direc- 

 tion of the aorta and the oesophagus, passes to the left, gains the entrance to the thorax, 

 and opens in front of the first rib, above the junction of the left jugular with the anterior 

 vena cava. 1 



" The varieties it presents in the Ox are numerous and very common. The rarest 

 disposition is lhat of a canal, single through- 

 out its entire length, such as it has been 

 de.M-ribed, and sii.-h as it is usually found 

 to bo in small ruminants (Fig. 309). This 

 canal (Fig. 306), single at its origin and 

 for the greater part of its extent, often bifur- 

 cates towards the base of the heart, or at a 

 i-h'Tt distance from its insertion. Of 



r.uii-hes, one passes to the right of the 

 oesophagus and trachea, the other to tin |. ft 

 of these, in following the ordinary direction ; 

 and, ut tin' entrance to the thorax, they eitln r 

 terminate s p.mttely, each in the angle of 

 union of the jugular and corresponding axil- 

 M. or together at the same point the 

 tful'f of ill.- two jugular veins. 



It happens that one of the branches of the bifurcated canal i- in its turn >iiMivid>d 

 into two smaller branches, and that the other experiences at the sain, tinn a similar 



I MI:\N. i. ..i mi: 



mi. ..\. 



DI 



(' Xundel has pointed out the curious fact, that in Ruminants, tho long, p<e:al. 

 lymphatic yland .situated ln-twern tin- layers of the m-<lm-tiimm and alxive the o- 



-'in.tim.s becomes so voluminous that its \\ei^ht iiiij-les rumination. . >p eiull y 

 \\li.-;i the animal is lyiiiL'. The lilns of ('<-.<! i- |.r. vi nt.<l from iitMt-ndiu^ into tli. 

 ewwphagiis, nml this may Ueomen fte<|ncnt and perwdio caiue of i 



