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.
It is just possible that the presence in the blood of this bile-product, the supply of which has been cut off by the hepatic disease, might have prevented the continual action of the Ague-poison.
There is another fact which gives additional probability to such an idea. Another remedy of a different kind has been used in all the diseases in which Quina is admissible, proving in some cases superior, and in other instances second only to it in its beneficial action. This is Mercury; used in remittent and yellow fevers; of the first importance in dysentery; employed by Dr. Baillie in Ague, and pronounced by him to be in some cases superior even to Quina. In small doses it is frequently of use in cases of debility and scrofula. And Mercury is a Cholagogue; i.e. an agent which is known to have the effect of promoting the secretory function of the liver. Thus we may conceive that Mercury, not given in excess, or to salivation, may operate in a different way to produce the same end as Quina. One explanation would suffice for both.
If this connexion between Tonics and the Bile were actually established, then we should be enabled to explain a matter which would otherwise seem difficult to understand,—how it is that small doses of Mercury may sometimes act as Tonics, though we know that the ultimate action of this medicine, like that of other Catalytics, is to deteriorate the blood. Even in scrofulous and enfeebled cases, small doses of blue pill or of Calomel are often signally useful; and not prejudicial, as is sometimes stated by those who confound their application with that of Mercury given in salivating doses. Under such a course, when judiciously enforced, we may see the dilated pupil contract to its normal size, and the pale enervated countenance become rosy and lively; and feel the weak compressible pulse to become hard and firm. Perhaps Mercury in such a case may be indirectly tonic, by restoring to the blood the natural tonic principle of the bile.
It will be conceded that it is a great merit in a theory, when it succeeds in explaining at the same time a number of different things in a plausible way. It seems that this hypothesis of the connexion of Tonics with Taurine, or some such element of the Bile, is capable of so doing. I am very far from asserting that it is proved, or from supposing that it is at all likely to be so in the present state of our knowledge of the subject; but I think that if not evidently true, it appears at least reasonable. And it may be observed, that even should this idea be completely overthrown, which is neither impossible nor unlikely, there would still seem to be left ample evidence to prove that Quina and other vegetable bitters act on the blood on the restorative principle,—though in what exact way is uncertain.