. Hand-book of physiology . Thus, also,the larger vessels, in the human subject, commonly empty!themselves after death; so that, although absorption is pro-bably usually going on just before the time of death, it is notcommon to see the lymphatic or lacteal vessels full. Theirpower of contraction under the influence of stimuli has beendemonstrated by Kolliker, who applied the wire of an electro- •magnetic apparatus to some well-filled lymphatics on the skinof a boys foot, just after the removal of his leg by amputation,and noticed that the calibre of the vessels diminished at leastone half (cx
. Hand-book of physiology . Thus, also,the larger vessels, in the human subject, commonly empty!themselves after death; so that, although absorption is pro-bably usually going on just before the time of death, it is notcommon to see the lymphatic or lacteal vessels full. Theirpower of contraction under the influence of stimuli has beendemonstrated by Kolliker, who applied the wire of an electro- •magnetic apparatus to some well-filled lymphatics on the skinof a boys foot, just after the removal of his leg by amputation,and noticed that the calibre of the vessels diminished at leastone half (cxc. July 1850). It is most probable that this con-traction of the vessels occurs during life, and that it consists, LYMPHATIC HEARTS. 289 not in peristaltic or undulatory movements, but in an uniformcontraction of the successive portions of the vessels, by whichpressure is steadily exercised upon their contents, and whichalternates with their relaxation. In reptiles and some birds, an important auxiliary to the Fig. 29.^. movement of the lymph and chyleis supplied in certain muscularsacs, named lymph-hearts (¥ig. 29).The number and position of theseorgans vary. In frogs an€. toadsthere are usually four, two anteriorand two posterior; in the frog theposterior lymph-heart on each sideis situated in the ischiadic regionjust beneath the skin; the an-terior lies deeper, just over thetransverse process of the third vertebra. Into each of these cavities several lymphatics open:the orifices of the vessels being guarded by valves, which pre-vent the retrograde passage of the lymph. From each heart asingle vein proceeds and conveys the Ijnnph directly into thevenous system. In the frog the inferior lymphatic heart, oneach side, pours its lymph into a branch of the ischiadic vein;by the superior, the lymph is forced into a branch of the jugu-lar vein, which issues from its anterior surface, and whichbecomes turgid each time that the sac contracts. Blood isprevented from passing from t
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