ancients had investigated the influence of pain as expressed in the figure and the muscles. Further on he quotes from the words of Paulo Somazzo's work, "Dell' Arte della Pittura," published in 1531, a passage describing the influence of the passions upon the muscles of the face, and still more minutely the different postures and contortions of the body. John Bulner, in his work entitled "Significative Muscles of the Affections of the Mind," published in 1649, expressed the opinion that every motion of the mind is indicated by a corresponding motion of the muscles, saying: When we assent, affirme, yield, grant, vote, confirme, confesse, admit, allow, or approve of a thing, etc., we are wont to nod or bend our head forward, thereason of which motion in these, seems an approving, which is made by the Imagination, seeing, or hearing, somewhat done or said which accordeth very well, and this power remaineth in the Braine or forehead part of the head where in the cell and Seat of the Imaginations lieth. "When any of these things give it contentment, suddenly it moveth the same, and after it all the muscles of the body."
There is in the subject before us a field for observation and description in which the artist and the physician may work together, observing and analyzing, with as much exactness as may be, the mode by which the varying conditions of the brain and mind are indicated to our eye, and may therefore be described by words, and by drawing or sculpture. We must study man in all aspects of the case, and when we see in the face, limbs, or body indications of his brain or mental condition, we should analyze and describe—first, the position of features and parts as we see them, then the muscles which produce those positions or movements, knowing that the muscular condition which has produced the movements or positions is the result of the state of the corresponding nerve-centers. It has been said that a man's face is an index of his mind, and this is true; for all the varying changes of expression in the face (except those of color) are due to changes in the facial muscles, and these solely depend upon changes in nerve-cells. The knowledge that we already possess of the nerve centers is from observation of the condition of the muscles. In a given case, by comparing the state of the muscles during life as they may be affected with paralysis or spasm with the brain-lesion found after death, and by collecting and comparing many cases, it has been found that destructive or irritative lesions of certain parts of the brain cause paralysis or spasm of a certain set of muscles corresponding. It is probable, then, that by carefully continuing these methods of examination—that is, by describing with accuracy all states which are indicated by conditions of the muscles—we may add still more to our knowledge of the functions of different parts of the brain, and gain a further insight into the pathology of that large group of nervous centers termed functional.