I have already made use of Taurine, one of the principles of the Bile, for the purpose of showing that among the natural constituents of the blood there is a substance which chemically resembles a tonic alkaloid, like Quina. This similarity admits of a further and more direct application. It is ascertained that many, if not all, of the diseases in which Quina and its kindred medicines are found to be of use, are connected with a derangement of the secretory functions of the liver. One of these diseases is the debility which is consequent upon Typhoid and other fevers. In these fevers the function of the liver is always more or less interfered with, though more obviously in some cases than in others. In strumous habits, in which generally bark is of signal service,--and was very strongly recommended by Cullen, Fordyce, and others,--there is very commonly a peculiar degeneration of the liver, which has been ably described by Dr. G. Budd. This state is distinct from the fatty enlargement common in Phthisis, in the early stage of which disease Quinine is also very serviceable. Quinine is often beneficial in Gout, in which the liver is always more or less deranged. Turning to periodic diseases, we find that impaired hepatic functions are the rule, and the absence of such disorder the exception. This will be at once admitted in the case of Dysentery, and of the Remittent and Yellow fevers of the tropics. It is also true of Ague. It seems even likely that the enlarged spleen may be partly caused by an obstruction to the circulation in the liver. This affection of the spleen is not uncommon in other liver diseases. In Typhus fever both the spleen is disorganized and the liver deranged. It is observed in tropical countries that severe forms of remittent not unfrequently pass into continued fever, which seems to point to some analogy between the two. Ague even may pass into Typhoid fever. And I have already referred to the fact that Quina has of late been strongly recommended in the treatment of continued fevers in general. Dr. Watson states that in New Zealand the biliary functions suffer so much in the intermittent which occurs there, that it is known among the inhabitants by the name of the "Gall-fever." (_Lectures on the Practice of Medicine_, vol. i. p. 793.) Let us now place in conjunction with these facts the similarity which has been pointed out between the bitter vegetable principles, and one of the chief constituents of the re-absorbed bile. Quina and others resemble Taurine; they tend to cure certain diseases; and these diseases depend on deranged hepatic functions. Does not this suggest the possibility that they may be of service by actually forming the Taurine, or by supplying its place in the blood? It is possible that such bodies as Quina and Cinchonia may be able to fulfil the functions of Taurine in the blood by remaining as they are, without even changing into it.