The absorbents usually flat in the dead body, because they are empty, never exhibit in this state a diameter proportional to that which injections give them; whatever may be the varieties of capacity, the fluids that we force into them always increase this capacity. It is this flattening after death, that often makes us in attempting to open them with a lancet, cut through both their parietes, and thus render it more difficult to inject them. The best proof of the extreme variety of the capacity of the absorbents, is the necessity of choosing particular bodies in order to inject them, the very great difficulties that often take place in finding them in some subjects, whilst they are seen immediately in others, and can be traced in the inferior and superior extremities, through the cellular texture, without having glands for a guide. It is not necessary then, after what has been said, to consider the caliber of the absorbent vessels in a determinate manner. Constantly varying, according to the state of the lymph they contain, they have no standard size to which we can refer their increase or diminution. This is the peculiarity of all the extensible and contractile canals, like those in the animal economy; it is that which prevents us from making any kind of calculation of their capacity. These varieties of the absorbents are not general as in the veins, all the great trunks of which, for example, are simultaneously dilated when there is an obstruction in the lungs. Here sometimes one only, sometimes many branches enlarge; the others remain contracted. Sometimes the dilatation is general in a part, very often there are remarkable disproportions of capacity in the same vessel; it is double in one place what it is in another, though it has not received branches. Authors have been much puzzled to determine the capacity of the thoracic duct. I believe it, for it is never found twice the same. These varieties do not depend on the constitution of the subject, but only on the functions, and the state in which these functions are found at death. Whether it be dilated above, contracted in the middle, exhibiting below a little bladder, called by some the reservoir of the chyle, &c. are circumstances the greatest number of which vary incessantly during life, according to the quantity, the nature of the lymph, and the obstacles to its course in this or that part. We find a hundred varieties of the thoracic duct and the absorbents in a hundred different subjects. The same subject has perhaps undergone these hundred varieties at the different periods of his life. If life returned and was destroyed many times in the same man, the venous and absorbent systems would exhibit a number of varieties equal to the number of times he had died. We see from these considerations to what are reduced all these minute examinations of proportion in the capacity of the vessels, which fill our books of physiology.