The development of a more accurate anatomy in the i 7th cen tury seems to have diminished the interest in physiognomy by substituting fact for fiction; and consequently the literature, though as great in quantity, became less valuable in quality. The principal writers of this age were T. Campanella, R. Coclenius, Clement, Timpler, J. E. Gallimard, Moldenarius, Septalius, Saun ders, C. Lebrun (a precursor of Charles Bell), Elsholz, de la Belliere, J. Evelyn (in the appendix to Numismata), Baldus, Bul wer (in his Pathomyotomia), Fuchs, Spontoni, Ghiradelli, Chiara monti, A. Ingegneri, Finella, De la Chambre, Zanardus, R. Fludd and others of less importance.
The 18th century shows a still greater decline of interest; the only name worthy of note is that of J. K. Lavater (q.v.). The popular style, good illustrations and pious spirit of his works gave them a popularity they little deserved, as there is no system in his work, which chiefly consists of rhapsodical comments upon the several portraits.
The physiological school of physiognomy was foreshadowed by Parsons and founded by Sir Charles Bell, whose Essay on the Anatomy of the Expression, published in 1806, was the first scien tific study of the physical manifestation of emotions in the terms of the muscles which produce these manifestations. In the later editions of this essay the thesis is elaborated with greater detail. Moreau's edition of Lavater, in 1807, was somewhat along the same lines. In 1817 Dr. Cross of Glasgow wrote his defence of a scientific physiognomy based on general physiological principles. The experiments of G. B. A. Duchenne (Mecanisme de la physiog nomie humaine, Paris, 1862) showed that by the use of electricity the action of the separate muscles could be studied and by the aid of photography accurately represented. These observations con firmed by experimental demonstration the hypothetical conclu sions of Bell. The machinery of expression having thus been indi cated, the connection of the physical actions and the psychical state was made the subject of speculation by Herbert Spencer (Psychology, 1855). These speculations were reduced to a system by Darwin (Expression of Emotions, 1872), who formulated the following as fundamental physiognomical principles : (I) Certain complex acts are of direct or indirect service, under certain conditions of the mind, in order to relieve or gratify certain sensations or desires; and whenever the same states of mind are induced the same sets of actions tend to be performed, even when they have ceased to be of use. (2) When a directly opposite state of mind is induced to one with which a definite action is correlated, there is a strong and involuntary tendency to perform a reverse action. (3) When the sensorium is strongly excited nerve-force is generated in excess, and is transmitted in definite directions, depending on the connections of nerve-cells and on habit.
The last of these propositions is adversely criticized by P. Man tegazza as a truism, but it may be allowed to stand with the quali fication that we are ignorant concerning the nature of the influence called "nerve-force." It follows from these propositions that the expression of emotion is, for the most part, not under control of the will, and that those striped muscles are the most expressive which are the least voluntary. To the foregoing may be added the following three additional propositions, so as to form a more com plete expression of a physiognomical philosophy :— (4) Certain muscles concerned in producing these skin-folds be come strengthened by habitual action, and when the skin diminishes in elasticity and fulness with advancing age, the wrinkles at right angles to the course of the muscular fibres become permanent. (5) To some extent habitual muscular action of this kind may, by affecting local nutrition, alter the contour of such bones and cartilages as are related to the muscles of expression. (6) If the mental dis position and proneness to action are inherited by children from their parents, it may be that the facility in, and disposition towards, certain forms of expression are in like manner matters of heredity.
Illustrations of these theoretic propositions are to be found in the works of Bell, Duchenne and Darwin, and in the later publi cations of Theodor Piderit, Mimike and Physiognomik (1886) and Mantegazza, Physiognomy and Expression (1890), to which the student may be referred for further information.
For information on artistic anatomy as applied to physiognomy see the catalogue of sixty-two authors by Ludwig Choulant, Ge schichte and Bibliographie der anatomischen Abbildung, etc. (Leipzig, 1852), and the works of the authors enumerated above, especially those of Aristotle, Franz, Porta, Cardan, Corvus and Bulwer. For physiognomy of disease, besides the usual medical handbooks, see Cabuchet, Essai sur l'expression de la face dans les maladies (Paris, 1801) ; Mantegazza, Physiology of Pain (1893), and Polli, Saggio di fisiognomonia e potogn:omonia (1837). For ethnological physi ognomy, see amongst older authors Gratarolus, and amongst moderns the writers cited in the various textbooks on anthropology, especially Schadow, Physionomies rationales (1835) and Park Harrison, Journ. Anthrop. Inst. (i8133). For the physical characteristics of criminals see Lombroso, L'Uomo.delinquente (1897) ; Ferri, L'Omicidio (1895) ; von Baer, Der Verbrecher (1893) ; Laurent, Les Habituis des prisons (189o) ; Havelock Ellis, The Criminal (Igor) ; A. Lenz, Grundriss der Kriminalbiologie (Vienna, 1927) ; L. Grimberg, Emotion and Delin quency (1928).