_Actual somatic death_ is marked by the cessation of breathing and pulse, the dilated pupils and semi-closed eyelids, the coldness and pallor of the visible mucous membranes and skin, and the clenching of the jaws with slight protrusion of the tongue. Yet these symptoms may be present in syncope and it may even be impossible to detect the beats of the heart, though the subject still lives. Pressure of the finger on a white portion of the skin or on a mucous membrane may give a further indication. If the indentation made by the finger is slowly effaced and if the blood again slightly reddens the part the presumption is against death. Even this is not infallible, since by pressure of gas in the internal cavities or deeper blood vessels, the blood may be forced back into the surface capillaries giving an appearance of circulation, after actual death. On the other hand any exudation or œdema will retain the imprint of the finger even in life. The general relaxation of the muscles and their lack of response to electric stimulation, and the setting in of cadaveric rigidity, and later still of putrefaction give more conclusive evidence of dissolution. ETIOLOGY: CAUSES OF DISEASE. Causes—simple—complicated: Proximate; Remote: Predisposing—race, genus, family, heredity, individual, environment, food, age, sex, temperament, idiosyncrasy, debility, plethora, interdependence of organs, embolism, mechanical influence. Exciting causes, intrinsic, extrinsic, inherent, acquired, heredity, dentition, heat, cold, atmospheric conditions, electricity, moisture, dryness, dust, darkness, light, soil, food, water, inaction, over-exertion, mechanical causes, poisons,—mineral—vegetable—animal, microbes, contagious, infectious, epizootic, enzootic, sporadic, panzootic, zymotic, mediate contagion, bacterial poisons. The causes of disease are simple or complicated, and in the latter case a single factor may be altogether harmless unless associated with another which also may have been innocuous alone. For example: the infecting germ of glanders (Bacillus Mallei) is harmless to the ox which lacks the predisposition to the disease:—feeding buckwheat is harmless to the dark-skinned animal, but is injurious to the white-skinned, if exposed to sunshine:—the chicken can bear with impunity exposure to cold or to the bacillus anthracis, but it cannot endure these two etiological factors combined. It follows that one cannot predict the same result from the same cause in every case. Yet with all concurrent conditions the same the result will follow with mathematical certainty. This will serve to illustrate the value of thoroughness in etiological knowledge, as the basis of a sound pathology. Etiology is primarily divided into =proximate= and =remote=. _Remote_ causes are again divided into =predisposing= and =exciting=.