the characteristic symptoms. All these facts point to some peculiarity in the properties of matter not yet investigated or at least not explained. If we may assume that reproduction is here an element of the persistence and apparent multiplication of active matter, I know only of one instance to compare with it. A gentleman about to deliver a lecture on the properties of arsenic, and its history generally, made two solutions of a given quantity of arsenious acid, in the following manner. He took a certain amount of distilled water, and the same of filtered Thames water, and made his solutions of arsenic by separate boilings, he then as soon as possible placed the liquids in identical bottles, carefully prepared for their reception. In the one which contained the arsenic boiled in river water, the hygrocrocis is now growing, while that boiled in distilled water remains perfectly limpid and free from any vegetable production. There can scarcely be a doubt, that the filtration of river water was not sufficiently purifying to remove the minute spores of some lower forms of vegetation, which not only live in arsenic but have resisted the temperature employed in boiling an arsenical solution to saturation. As to the first class, or truly reproductive and {171} morbid poisons, the most heterogenous ideas have from all time existed. I have introduced the notice of the above poisons, viz. the Amanita, and that which engenders the milk sickness, to compare the results of the morbid poisons on the human body with them, and also to associate them with the effects of diseased grain. From the Amanita and that other fungoid matter which is said to produce the milk sickness, there appears to be a purely toxic action on the system, but in the instance of diseased grain, a blood disease, ending in gangrene, or a specific and peculiar action of the generative organs is the consequence, and where the latter occurs, the poison usually expends itself on these parts, either by inducing abortion, or augmenting the catamenial secretion. Now, the morbid poisons, if studied only in their results, shew that there is a combination of these two actions. There is usually, in the first place, a toxic or poisonous action, and secondly, a deteriorating or decomposing action on the blood, by which there is a tendency to low or asthenic inflammation and gangrene. It matters not what form of fever we take as an illustration, whether intermittent, pestilential, or exanthematous, either will serve the purpose of shewing how completely the effects of vegetable organic poisons resemble those which for the sake of distinction (I suppose) have been denominated Morbid Poisons.