1018 



PHYSIOLOGY 



a large extent by the contractions of the skeletal muscles. In the smaller 

 lymph-radicles the pressure of lymph may attain 8 to 10 mm. soda solution. 

 In the thoracic duct, at the point where it opens into the great veins of the 

 neck, the pressure is obviously the same as in these veins, that is to say, 



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assies" 



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' ' ''9fi ' ' ' ' I '_)_' .v' I I '-' I I 'eWm.in'.hoL 



oiaUse^gib 1 ! ' 20' 



Bled to 240 com Inj. 18 grams dextrose 



FIG. 477. Effect on lymph flow and on arterial and venous pressures of injection 



of concentrated solution of glucose. 



In B the animal was bled to 240 c.c. before the injection. The double line 

 = lymph flow in c.c. per ten minutes; thin line = portal vein; thick line = 

 carotid artery ; dotted line = inferior vena cava. 



from - 4 to mm. Hg, the negative pressure being occasioned by the aspira- 

 tion of the thorax. This difference of pressure is sufficient to cause a certain 

 amount of flow. It must be remembered, however, that under normal 

 circumstances no lymph at all flows from a resting limb. The only part of 

 the body which gives a continuous stream of lymph during rest is the alimen- 

 tary canal, the lymph in which is poured out into the lacteals, and thence 

 makes its way through the thoracic duct. Movement, active or passive, 

 of the limbs at once causes a flow of lymph from them. Since the lymphatics 



