It only remains for us to offer a few remarks on the connexion between the function of ab sorption, and the other vital actions of the system, especially with the two leading princi ples of contractility and sensibility. We have already had occasion to remark on the con nexion of absorption with muscular contracti lity, and although it may be difficult, or even impossible, to demonstrate the muscular fibres, or to exhibit any apparatus of this description, by which the action of the vessels can be ac counted for, still we have strong reason for supposing that the absorbents possess this power, and that it is the main cause by which their contents are propelled.
With respect to the relation which subsists between the nervous and the absorbent systems, we are induced. to suppose, both from anato mical and from physiological considerations, that it is merely of an indirect nature. From the researches of the anatomists, we learn that there are few nerves sent to the absorbent vessels or glands, and that even these seem rather to pass by them, in order to be transmitted to some other organs, than to be ultimately des tined for the use of the absorbent system. The action of the mouths of the lacteals, or the power by which they are enabled to take up the substances that are afterwards transmitted along them, is involved in much obscurity, as is likewise the case with the power which these vessels to possess of changing the nature of their contents. Both of these have been re
ferred to the nervous influence, but this has been done in that loose and general way, which is too frequently met with in the reasoning of physiologists. We do not perceive, in either case, how it can be referred to this power, nor how it can be employed' in any way to explain or elucidate the effects that are produced.
It is admitted that the chyle is elaborated during its passage along the lacteals, and be comes more nearly assimilated, both in its phy sical and chemical properties, to the blood. Still, however, its complete sanguification does not take place until it leaves the lacteals, and it becomes a very interesting subject of inquiry, by what means this is effected ; in what degree the function of respiration contributes to it, whether the abstraction of carbone and the in troduction of oxygene, which is supposed to be effected by the passage of the blood through the lungs, is the immediate cause of the con version of chyle into blood ; whether it be brought about more gradually, by the removal of the various secretions and excretions, or whether there be any particular organ, which may more especially produce the change in question. These are all of them points of high interest, but as they are concerned in an indi rect manner only with the subject of this article, and as they will be considered in the appro priate parts of this work, we shall not pursue the inquiry any further.