74 BIOLOGY. [BOOK i. 



throwing itself into two huge venous vessels, the right and the 

 left subclavian veins. 



The lymphatic plasma, so analogous to the sanguineous plasma, 

 acts exactly like it when drawn from the vessels. There is 

 ovolvement of plasniine and the formation of a fibrinons clot. 



Like the blood, the lymph is alkaline. It contains nearly the 

 same immediate principles, but in smaller quantity, and more 

 diluted. As its course is very slow, a result is that it has not 

 everywhere, like the blood, a composition observably uniform. 

 On the contrary, this composition varies with every region, with 

 the hour of digestion, and so on. In general the lymph is the 

 more charged with substances, the nearer our examination 

 extends to its chief trunks of communication with the sanguineous 

 system. 



In the mammifers the lymph is a liquid essential, indispensable 

 to the duration of life. If in these animals we form a fistula 

 in the largest lymphatic trunk, the thoracic canal, the lymph 

 being no longer able to blend with the blood in sufficient quantity, 

 we see the patients rapidly grow lean and die, even while 

 continuing to take food. 



What is the special province of the lymph and of the lymphatic 

 circulation 1 ? This is still a very obscure point of physiology. 

 Evidently the lymphatic is an adjuvant of the circulatory 

 system ; it connects the immediate principles in the digestive 

 system and in the mechanism of the tissues, then pours them 

 into the whole grand circulation. Its special function the most 

 probable is to form white globules and to convey them to the 

 great sanguineous current. The fact that a fistula of the thoracic 

 canal is followed by death, proves conclusively that the lymphatic 

 system is not a mere ornamental apparatus, and that it plays in 

 the economy one of the most important parts. 



