The majority of medicines that affect the blood permanently belong to the mineral kingdom, while most of those that powerfully impress the nerves are derived from vegetables. But to the rule that Hæmatic medicines are of mineral origin, we have already found one important exception in the case of Quinine and Tonics. Colchicum appears to be another instance of the kind. The great and obvious use of this remedy is that action in the blood which above is classed first, i.e. its influence in the counteraction of gouty disorders. We have already considered at some length (p. 200) a number of Antiarthritic medicines that seem to act in a chemical manner. Colchicum is not one of these. It is a General Sedative, and a Cathartic; in large doses, an irritant poison. It seems also to increase the amount of other secretions, particularly the urine and the bile. But it is used beneficially in Gout; and it is assumed that in the cure of this disorder it exerts an action in the blood, inasmuch as its remedial operation appears to be independent of its nervous and glandular actions. This hæmatic action must be of the Catalytic kind, and may probably consist in the exertion of a special influence over the erring assimilative processes, which tends to resolve them into a right direction. But it should be observed that at least three other explanations of the action of this remedy have been proposed, each of which is possessed of a degree of plausibility. Some have ascribed its efficacy to the union of a cathartic with a sedative effect, and have even substituted for it a combination of Opium with a drastic purgative. Those who adopt this view of its action aver that Colchicum acts best when it purges freely. But though Purgatives are often of use in gouty disorders, it is generally found that Colchicum operates most favourably when given in too small a dose to produce any purging. Colchicum stimulates the function of the liver, which is generally deranged in gouty disorders. Mercury, which also promotes the secretion of bile, is in this way useful in Gout. It seems that the formation of this secretion is in some manner essential to the integrity of those blood-processes which are disturbed in arthritic diseases. It might therefore be supposed that Colchicum too acted as a Cholagogue. But it is not clear that it increases the secretion of the bile in any very marked degree. Thirdly, it is affirmed by some that this medicine is of use in eliminating uric acid from the blood, this product being supposed to accumulate in the system before the paroxysm of Gout. It is said that under the action of Colchicum the natural amount of this substance in the urine is much increased. This would be an important fact if it were certainly proved. But it does not seem to be so; nor is it clearly shown that the observed increase in uric acid is not a symptom of the disorder, rather than of the treatment.