I would ask the particular attention of those interested in this science to the classification and nomenclature which I here present. It is the result of a careful collation of all the leading European writers on the subject and of consultation with several of the most thoughtful in this country.
There is, unfortunately, considerable diversity in the arrangements and terms adopted by different authors, and it is most desirable that a uniform phraseology be adopted in all countries. That which I offer aims to be exhaustive of the science and to adopt, wherever practicable, the expressions sanctioned by the greater number of distinguished living authorities in its literature.