The fundamental principle of Dr. Perry's treatise is, that the hair is ever in danger of being killed by much cherishing. He regards it as a delicate vegetable, growing in a tender soil, and amply supplied by Nature with the elements needed for its support and development. The skin of the head should not, he tells us, be subjected to any rough treatment, neither should it be exposed to sudden alternations of temperature. Cleanliness, gentle usage, and mild, innocuous specifics--vegetable, whenever possible--are his reliance to keep the hair in good order, and restore the proper tone when lost by negligence or disease. The harsh friction of the stiff, "penetrating hair-brush," the scraping of the fine comb, "the 'shampooing' operation of the hairdresser, with his exacerbating compound, a hundred degrees too violent, and his cataract of cold water at the end," are all condemned as injurious, together with the myriad nostrums in the form of oils, pomades, and the like. In dealing with these last, the author is indeed severe, remarking that "generally they are most mischievous, as well as common and filthy, mixtures, with nothing refined or elegant about them but their titles." For greasy compounds he has no tolerance, charging upon them, that, although they may for the moment lubricate and soften the hair, they burden the scalp, clog its pores, deaden the roots of the hair, and cause or increase many abnormal conditions of the cuticle. And certainly the formulae; which are quoted in the Appendix go far to arouse in the reader the disgust for the popular preparations of the day which the writer does not attempt to conceal. In those chapters which discuss the scalp and hair in disease, Dr. Perry takes the ground, that the trouble is primarily in the skin, and that remedial treatment should therefore be directed to it. He mentions the different eruptive and other affections in turn, and quotes the method of procedure advised by medical men, in connection with a statement of the manner of practice which he has successfully adopted, illustrating his views with very good wood-cuts derived from the atlases of Wilson, Neligan, and Dendy. In many cases he believes constitutional debility to be the primary difficulty, and recommends a tonic regimen as the best preliminary to a course of local treatment. Without, of course, attempting to give minute directions for the management of all diseased conditions of the head and hair,--which would be alike impracticable in a volume of this popular character and unprofitable to himself as a practitioner in such cases,--Dr. Perry gives a large number of recipes which his own experience or that of his favorite authors has proved to be trustworthy and serviceable, the ingredients of which are cleanly, simple, and agreeable, adding plain rules for the rational culture and preservation of the hair.