From the pathological and histological investigations described on p. 81, and from the fact that particles of lead are very readily taken up by white blood-corpuscles, we can conclude that absorption of the finer lead particles gaining access to the lung takes place through the medium of these phagocyte cells, as such cells are well known to exist within the alveoli of the lung. The stored-up carbon particles found in the lungs in dwellers in cities show that such transference of particles from the alveoli to the inner portions of the lung trabeculæ is a constant phenomenon, and it is therefore easily understood how rapidly any fine particles not of themselves irritant may be easily taken up by the tissues. Once having gained access to the interior of the cells, the particles subjected to the action of the serum of the blood in the ordinary process of bathing the tissues by the exuding lymph--nay, more, actual particles of lead--may thus be actually transferred bodily into the finer blood-spaces, and so be carried forward to the general circulation. Such particles as remain fixed in the lung will undergo gradual absorption, and the constant presence of carbonic acid in the circulating blood brought to the lung undoubtedly largely contributes to their solution, and there is no need to presuppose the necessity of some recondite interaction of organic acid for the solution of the inhaled lead in the lungs. In the absorption of the substance from the intestine, it may go direct into the blood-stream in a similar fashion through the lacteals along the lymph channels, and so into the thoracic duct, and finally into the general circulation. On the other hand, a certain amount, probably not an inconsiderable portion, is taken up by the portal circulation and transferred direct to the liver itself. Chemical analysis of the liver supports this view, as does also the considerable amount of stress thrown upon the liver when poisoning has taken place from the intestinal canal on administration of massive doses of a highly soluble lead compound. According to Steinberg[16], excretion of lead takes place partly from the liver by the bile. This is probable, but there is no experimental evidence at the present time to support the view. If such an excretion does take place, the form in which the lead is excreted is probably one in which it is no longer soluble by digestive action. On the other hand, it may be in so soluble a form as to become reabsorbed from the intestine, thus setting up a constant cycle. But such a theory is one that would require a considerable amount of experimental evidence to support it before it could be relied on.