After the study of the Mathematics comes that of _Natural History_, which will be found to be almost equally beneficial, requiring as it does, the unremitting attention of the student, his perambulation of the open country, and the personal observation of all animated objects. This peculiar influence of the above-mentioned studies ought particularly to engage the attention of persons who superintend the education of youth; there being no doubt that the effervescence of youthful passions may, to a great extent, be allayed by directing the juvenile mind to either of those studies, according as the constitution exhibits greater or less ardour and precocity. Sometimes, however, there are found idiosyncrasies which bid defiance to remedies of this description, but, nevertheless, yield to the force of medicine: of such, the following is an instance: "A man, by profession a musician, of an athletic figure and sanguine complexion, with red hair, and a very warm temperament, was so tormented with erotic desires that the venereal act, repeated several times in the course of a few hours, failed to satisfy him. Disgusted with himself, and fearing, as a religious man, the punishment with which concupiscence is threatened in the Gospel, he applied to a medical practitioner, who prescribed bleeding and the use of sedatives and refrigerants, together with a light diet. Having found no relief from this course of treatment, he was then recommended to have recourse to wedlock, and, in consequence, married a robust and healthy young woman, the daughter of a farmer. At first, the change appeared to benefit him, but, in a short time, he tired his wife out by his excessive lubricity, and relapsed into his former satyriasis. His medical friend now recommended frequent fasting, together with prayer, but these also failing of effect, the unhappy man proposed to submit to castration, an operation which was judged to be highly improper, considering the great risks the patient must necessarily incur. The latter, however, still persisted that his wish should be complied with, when, fortunately, a case having occurred in Paris, in which a person afflicted with nephritic pains occasioned by the presence of a calculus, was cured by a preparation of nitre, at the expense, however, of being for ever incapacitated for the pleasures of love, the hint was taken, and doses of nitre dissolved in _aqua nymphæ_ were given, night and morning, during the space of eight days, and with such success that, at the end of that time, he could scarcely satisfy the moderate claims of his wife."[193]