These groups, though differently placed, correspond to six of Eberle's seven classes. The class acting on the muscular system is omitted. The subdivision here is more accurate and scientific. _Hæmatics_ or blood-medicines, are divided into two classes. _Spanæmics_ the first of these, are named from their tendency to impoverish the blood. _Hæmatinics_ including the compounds of Iron, tend to enrich it. In the first division are included the medicines commonly termed Alteratives, as well as Acids, Alkalies, the compounds of Lead, Silver, Copper, etc. In the selection of the above name attention is paid to the abstract physiological effect of these medicines, rather than to their therapeutical applications. The impoverishing of the blood may be the ultimate action of such a medicine as Potash or Mercury, but not exactly the primary operation for which it is used in medicine. It is produced by the remedy when taken in excess, and not when given in small doses. _Neurotics_, or medicines which act on the nerves, are divided into those which affect the brain and spinal system, and those which are supposed to influence the ganglionic system, and through it the heart and great vessels. (When we shall afterwards discuss the action of nerve-medicines, it will be seen that it is very difficult, if not impossible, to enforce this distinction.) The different kinds of Narcotics form the first division, while the second includes Stimulants and vascular Sedatives. The class of _Eccritics_ includes all medicines acting on the glands, commonly called Evacuants. The details of this arrangement, to which I shall at present venture to object, are, first, the multiplicity of classes, and secondly, the inclusion of certain medicines in the division of _Cerebro-spinals_. Three of the classes seem to be superfluous, and only tend to confuse. There is a class of _Pneumatics_, acting on the respiratory organs. But Expectorants are found elsewhere among _Eccritics_; and those medicines which influence the nerves of the lungs, among _Neurotics_. The same with _C[oe]liacs_; for Cathartics, found among _Eccritics_, are the most important medicines acting on the intestines. _Genetics_ contain medicines which control the uterine and sexual systems, which may all be reckoned among _Neurotics_. And yet this multiplicity of names is consistently employed in carrying out the principle of this classification, which is, to arrange according to the different parts of the system all substances which have any tendency to act on those parts.