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Show «MM-war 1-.... . WW W' -,,, ,. ,_.___-_.--_.._.. 174 Offlzc particular Distribution (ft/M Absorbent Vusscls in My (Ii/f 'mt Par/5 rf [1W Body. mittat in ductum nequaquam. Ad id munus mihi vix suf-hcere videttn‘.j' homi- He says also, of the other valves of this duct, " Rara tamensunt 1n ne, ut cxstcnt, qui negant earum numerum supcrare duodccnn, parumque lu‘ conspicna, ut ctiam officio suo non valdc accurate fungantur, nee totum men (luctus thoracici claudant, chylumquc rclabt ceramque retrorsum de- they can-serve, scendere pcrmittant." For my ownpart, I know no other use lnndcrlpgthc than that of preventing the retrograde motion of the chylc, or blood in the veins from passing down the duct. The valves allowing injec- are tion to escape in the dead body, proves nothing, as many circumstances body, so wanting which e. ‘3th in the living body,- however, in the dead function, well do the valves at the orifice of the thoracic duct perform their that it is exceeding rare indeed to find the injection passing from the vein 17.; of the blood, and perfectly white; at other times the mixture of red and white was so uniform, that there must have been at least as much cliyle in these cavities as there was blootl. From these facts it must follow, that the cliyle is poured into the veins in full stream, and that there are pcriods when the absorbed fluids are thrown into the \‘eins in greater quan- tity, and with greater force. I even doubt if the exhaled fluid of surfaces and cells be in sufficient quantity, that by its constant absorption it should be able to keep the absorbents in full employment, and always distended. I am even certain, that the absorbing powers are frequently less active; and that, upon all these occasions, the valves will be brought into action, to pre- vent the blood of the veins from pas. ng into the duct. into the thoracic duct, 1 do not recollect its ever happening to me when the injection was viscid. I admit that the valves can be ofno use, except on The thoracic duct is sometimes double through its whole length: then is a preparation of this kind in the collection in \l'inthnilLstrcct, which 1 injected many years ago with quicksilver; one ofthese thoracic ducts is in- certain occasions; and that, as the fluids in the thoracic duct are generally able to overcome the resistance of the venous blood to their entrance into sertcd into the right subclavian vein, and the other into the left. I have also sometimes seen it triple, or nearly so. Sometimes the thoracic duct is the veins, this alone prevents the blood from passing into the duct, and the inserted into the right subclavian vein, instead of the left, and then the trunk of the absorbents of the left side, in every respect resembles the or- valves are not called into action: but there are two occasions in which I have no doubt that these valves are wanted :-The first is, in straining and coughing, and other violent efforts, the blood of the subclavian and jugular veins is prevented from passing into the heart, of course distends the sides of those vessels with uncommon force, such as the absorbed fluids would not be capable of overcoming; the venous blood would then descend into the thoracic duct, did not these valves prevent it; the motion of the chylc would also, at that time, become retrograde, did not the other valves prevent this. There is also another occasion on which it appears to me more than pro- (linary appearance of that of the right side. There is also a preparation of this kind in the Collection at IViutlmill-strect, which I injected from the umbilical vein ina child at birth; the injection was incited tallow, soli-‘ncd with some turpentine, and coloured with vcrmilion: the injection got into the thoracic duct, which was distended with a white injcction through its whole length, and was inserted into the right subclavian; the colour had been dropt by the way, as we have frequently seen it when a similar injec- tion has passed from the t‘vtrt‘initics of arteries into the beginning of veins, bable that the valves are called into action 2-Doctor Hunter stISpected that the chyle went into the blood, at the angles between thcjugulars and sub- and which is a proof of its having passctl thro .,rh extremely fine tubes!" From what I " )uctus thoracicus per arterias aliquando se rcplcri p; us (‘st olco polls" sinium terebinthitue rubro. Solct vero id Olt‘tllh C(‘lOl't'tn dcponcrc." I suspect here, that the injection passt‘d into the mouths of the l}llllll12lllC vasa clavians, drop by drop, and that it was constantly doing so. have seen, in opening living or recently dead animals, I am persuaded that it must be otherwise: for there are only particular periods when the chylc is poured into the intestines, at which periods only it can be absorbed. I have also seen very large-quantities of chylc in the subclavians, vena cava The same thing I find had happened to Muller and Mcltcl. ‘ ThisI have stcn when the injection passttl from the its of the pin nutter into its veins, where, though red at first, it returned white by the Him. ~uperior, and right attricle of the heart, floating as it were upon the surface of IIallcr say, In the arms, lzowtvn, l have often known it return by the veins on the points of the fingur unchanged. vasorum, |