of hydrogen contained in a tube, with a piece of platinized platina in contact with the metallic salt : nitric acid and persalts of iron, on the other hand, yielded their oxygen by the influence of the same agent.
The general conclusion which he deduces from his experiments is that, when a metallic solution is subjected to voltaic action, water is decomposed, its oxygen passing in one direction, and its hydrogen in the opposite direction; the latter element performing at the moment of its evolution at the negative pole the same part with respect to a solution of sulphate of copper, that a plate of iron or zinc would per- form to the same solution.
March 16, 1843.
FRANCIS BAILY, Esq., V.P., in the Chair.
William Brooke O'Shaughnessy, M.D., was balloted for, and duly elected a Fellow of the Society.
The following papers were read, viz. —
I. " On the import and office of the Lymphatic Vessels." By Robert Willis, M.D. Communicated by John Bostock, M.D., F.R.S.
That absorption is the special office of the lymphatic vessels was, until very lately, a universally received doctrine in physiology : but it is now admitted that if they exercise this faculty, it can be only to an inconsiderable extent ; and physiologists of high authority have even denied that they possess any absorbing power at all. This last is the opinion of Magendie, in which the author concurs. So lately as 1841, Rudolph Wagner asserted that "neither anatomical nor physiological considerations render any satisfactory account of the import and office of the lymphatics," which thus, shorn of their ancient office, were repudiated as a superfluous apparatus in the animal mechanism. The grand organs of absorption the author believes to be the veins ; and a principal object of his paper is to point out the mode in which they acquire this remarkable faculty. The principal condition which this faculty of imbibition implies, is a difference in density between the contents of the vessels which are to absorb, and the contents of those which furnish the matter to be absorbed. If the several constituent materials of the body, both fluid and solid, were to remain in the same unaltered state, both chemi- cally and physically, there could be no interchange among them : in order that mutual penetration may take place between two ele- ments, the one must differ from the other : that which is designed to absorb must be, with relation to that which is to be absorbed, more dense ; that is, must contain a smaller quantity of water in proportion to its solid ingredients. For the continuance of the de- licate processes concerned in the access and removal of the nutrient fluids, it is necessary that a difference should be established be- tween the arterial and the venous blood in respect of density. This purpose the author conceives is accomplished by the abstraction from
