The formulas universally made use of in characterising pleasure indicate this vague position of the problem: “Agreeable states are the correlatives of actions which conduce to the well-being or preservation of the individual.” “Generally speaking, pleasures are the concomitants of medium activities, where the activities are of kinds liable to be in excess or in defect” (Herbert Spencer). “Experience attests that, in all the sensory regions, sensations of moderate energy are specially accompanied by a feeling of pleasure. Thus this feeling connects itself with the sensations of tickling due to cutaneous excitations of slight energy” (Wundt). According to this writer, the gamut of pleasure is less rich and extensive than that of pain, and he finds the proof of this assertion in the language expressive of universal experience. “Language,” he says, “has created numerous expressions for disagreeable feelings, emotions, and inclinations, while the joyful moods of the mind are dismissed with a brief general designation. This phenomenon arises less from the fact that man observes with especial care and minuteness his disagreeable or troublesome states, than from the greater uniformity which pleasurable feelings in reality possess. This is particularly evident in the case of the sensory feelings [those connected with the sensations]. Pain has not only numerous degrees of energy, but numberless gradations according to its seat.” Mantegazza, when determining the synonyms of pleasure, appears to uphold the contrary view.[32] For my own part, I am of Wundt’s opinion. ----- Footnote 32: _Fisiologia del piacere_, Part II., chap. ii. He enumerates the following expressions:—_Gusto_, _diletto_, _compiacenza_, _soddisfazione_, _conforto_, _contentezza_, _allegria_, _buon umore_, _gioia_, _giubilo_, _tripudio_, _delizia_, _voluttà_, _felicità_, _solletico_, _rapimento_, _trasporto_, _ebbrezza_, _delirio_. Perhaps the Italian language is in this point richer than the German. ----- The anatomical and physiological conditions of the genesis and transmission of pleasure are a _terra incognita_. In cases of physical pleasure, what takes place at the peripheral terminations, in the nerves, in the cerebro-spinal axis? Most authors do not even propound these questions. The physiology of pain, in spite of its uncertainties, is rich and instructive compared with that of pleasure.