Class VI. SEPTIC and PUTREFYING POISONS. By this term are included those poisons which, according to _Orfila_, “occasion a general debility, dissolution of the humours, and syncope, but which do not, in general, alter the intellectual faculties.” The articles of this class belong almost entirely to the animal kingdom, with the exception perhaps of a few gaseous compounds, and the _Spurred Rye_, or _Ergot_, viz. _venomous animals_; _animals whose fluids have been depraved by antecedent disease_; _the poison of fishes_; _substances in a state of putridity_; _Spurred Rye_, or _Ergot_. Such is the classification which, for reasons already stated, it is our intention to adopt on the present occasion. We shall, however, in an additional chapter, under the title of “_Aërial Poisons_,” treat of those substances which are exclusively capable of acting upon the body through the medium of the atmosphere, or which require to be in a state of vapour, or gas, to ensure their operation. With regard to the classification of _Fodéré_ and _Orfila_, we must here observe that we follow it only conventionally, and that, while we acknowledge it as being very convenient for the consideration of poisons, in reference to their forensic relations, yet we must not be considered as insensible to its many defects and fallacies. In the first place, it has little or no reference to the enlarged views of the modern physiologist, respecting the “_modus operandi_” of poisons; nor indeed is its construction susceptible of such modifications and improvements, as can ever render its degree of perfection progressive with the advancement of science. In the next place, the classes are in many particulars ill-defined, and indistinctly, if not erroneously, divided. How questionable, for instance, are the boundaries which separate _Corrosive_ from _Acrid_ poisons? even the respective species of each class are, in many instances, less allied to each other than the great divisions to which they are subordinate. As an exemplification of this fact we have only to compare the physiological actions of _Arsenic_ and _Corrosive Sublimate_; the former of these substances occasions death by being absorbed, and thus acting as a vital agent, the latter, by its local action as a caustic on the textures with which it comes in contact. In the same manner, if we examine the individual actions of the different species composing the class of “_Acrid_” poisons, we shall find the same want of uniformity; thus the _Spurge-flax_, and the _Jatropa Curcas_ act by occasioning a local inflammation, while the _Hellebore_, being rapidly absorbed, exerts a fatal action on the nervous system, and produces only a very slight inflammation. The class of Narcotic poisons is more absolute in its definition, and more uniform in its physiological affinities, and therefore less objectionable, than the divisions to which we have just alluded; but the propriety of the