CHYLOSIS. 651 



these fibres, taking their point d'appui in the circular fibres, dilate the 

 superior sphincters by drawing the circumference downwards. By this 

 method, the fluid that enters a lymphatic irritates the vessel, which 

 contracts upon itself, diminishes its cavity, and sends on the fluid 

 through the open sphincter. A kind of peristaltic action, he conceives, 

 and in this view he is confirmed by MM. Lacauchie, 1 Gruby, and 

 Delafond, 2 exists in the lymphatics similar to that of the intestines, 

 which may be observed very distinctly, he says, in the lacteal vessels 

 of the mesentery of animals, if opened two or three hours after they 

 have been well fed. 



Moreover, that the lacteals and lymphatics are possessed of a power 

 of contraction is corroborated it is argued by the following reasons. 

 First. They are small; and tonic contractions are generally admitted 

 in all capillary vessels. Secondly. The ganglions or glands, which cut 

 them at intervals, would destroy the impulse given by the first action 

 of the radicles; and hence require some contraction in the vessels to 

 transport the chyle from one row of these ganglions to another. Thirdly. 

 If a chyliferous vessel be opened in a living animal, the chyle spirts 

 out, which could not be eifected simply by the absorbent action of the 

 chyliferous radicles; and, Fourthly r , in a state of abstinence, these ves- 

 sels are found empty; proving, that notwithstanding there has been an 

 interruption to the action of chylous absorption, the whole of the chyle 

 has been propelled into the receptaculum chyli. It is obvious, however, 

 that most of these reasons would apply as well to the elasticity as to 

 the muscularity of the outer coat of these vessels. 3 A more forcible 

 argument is derived from an experiment by Lauth. 4 He killed a dog 

 towards the termination of digestion; and immediately opened its abdo- 

 men, when he found the intestines marbled, and the chyliferous vessels 

 filled with chyle. Under the stimulation of the air, the vessels began 

 to contract, and, in a few minutes, were no longer perceptible. The 

 result he found to be the same, whenever the dissection was made within 

 twenty-four hours after death ; but, at the end of this time, the irrita- 

 bility of the vessels was extinct; and they remained distended with 

 chyle, notwithstanding the admission of air. These experiments lead 

 to a deduction, in the absence of less direct proof, scarcely doubtful; 

 that the chyliferous vessels possess a contractile action, by the aid of 

 which the chyle is propelled along the vessels. In addition to these 

 propelling causes, the pulsation of the arteries in the neighbourhood of 

 the vessels, and the pressure of the abdominal muscles in respiration 

 have been invoked. The former has probably less effect than the latter. 

 It is not, indeed, easy to see how it can be possessed of any. Of the 

 agency of the latter we have experimental evidence. If the thoracic 

 duct be exposed in the neck of a living animal, and the course of the 

 chyle be observed, it will be found accelerated at the time of inspira- 

 tion, when the depressed diaphragm forces down the viscera, or when 

 the abdomen of the animal is compressed by the hands. We shall find, 

 too, hereafter, that the mode in which the thoracic duct opens into the 



1 Comptes Rendus, 15 Mai, 1843. 2 Ibid., 5 Juin, 1843. 



3 Adelon, Physiologie, etc., iii. 31. 4 Essai sur les Vaisseaux Lymphat., Strasb., 1824. 



