CH. xiv. FURTHER PHYSIOLOGICAL DISCOVERIES. 513 



that these lacteah empty themselves into a large tube called 

 the thoracic duct, which carries the fluid into the principal 

 vein, and so to the heart; and finally, in 1649, a Swede 

 named Olalis Riidbeck discovered an immense number of 

 fine thread-like tubes running from all the principal parts of 

 the body, and carrying nourishing matter to the thoracic 

 duct, and so through the great vein to the heart. He called 

 these tubes lymphatics ; but in reality the lymphatics and 

 lacteals are the same vessels, coming from different parts of 

 the body and supplying the material for new blood. It is 

 easy to understand that when physiologists knew not only 

 how the blood circulates through the body, but also how a 

 fresh supply of blood is being constantly provided, they had 

 made a great step towards tracing out the workings of a 

 living body. 



Chief Works consulted. Sprengel, 'Hist, de la Medecine,' 1815; 

 Harvey's 'Anatomical Exercises,' 1673; Aikin's ' Biog. Mem. of 

 Medicine till the Time of Harvey,' 1780 ; Huxley's ' Elementary Phy- 

 siology ; Carpenter's ' Physiology ; ' Kirke's Physiology j ' Cuvier, 

 'Hist, des Sciences, etc;' D'Orbi^ny, 'Diet des Science*,' 



