It is undoubtedly surprising that the passions, essentially as they enter into our relations with the beings which are placed about us, that modifying as they do at every moment these relations, that animating, enlarging, and exalting the phenomena of the animal life, which without them would be nothing but a cold series of intellectual movements; it is astonishing, I say, that the passions should neither have their end, nor beginning in the organs of this life, but on the contrary, that the parts which serve for the internal functions, should be constantly affected by them, and even occasion them according to the state in which they are found. Such notwithstanding is the result of the strictest observation. I shall first observe, that the effect of every kind of passion is at all times to produce some change in the organic life. Anger accelerates the circulation of the blood, it multiplies the efforts of the heart. The passion of joy has not indeed so marked an influence upon the circulation, but alters it notwithstanding, and carries it lightly towards the skin. Terror acts inversely; this passion being characterized by a feebleness in the vascular system, a feebleness, which in hindering the blood from arriving at the capillary vessels, occasions the paleness which at such time is so particularly remarked. The effects of sadness and sorrow are nearly analogous. So great indeed is the effect which the passions occasion upon the organs of the circulation, as even to arrest them altogether in their functions, where the affection is very powerful. In this way is syncope produced, for the primitive seat of syncope is always, as I shall soon prove it to be, in the heart, and not in the brain. In this the latter organ ceases to act, only because it ceases to receive the excitant necessary to its action. Hence also may happen death itself, the sometimes sudden effect of extreme emotion, whether such emotion as in anger so far exalts and exhausts the powers of the circulation, as not to leave them any further excitability, or whether as in the death occasioned by excessive grief, the powers at once excessively debilitated, are no longer capable of returning to their usual condition. If the total and instantaneous cessation of the circulation be not occasioned by this debility, a variety of lesions in the blood vessels may be, notwithstanding, the effect of it. Desault has remarked that diseases of the heart, and aneurisms of the aorta, were augmented in number during the revolution, in proportion to the evils which it produced. Nor does respiration depend less immediately upon the passions; that oppression, that anxiety, and sense of suffocation, which is the sudden effect of profound sorrow, must imply in the lungs a remarkable change and sudden alteration. In that very long series of chronic or acute affections, the sad attribute of the pulmonary system, must we not often look to the passions to find the principle of the disease?