The trophic causes of inflammation are those whose action is supposed to take place through the influence of nerves. Although, as has already been stated, a faulty innervation of tissues is an important element in favoring the action of various inflammatory causes, there remain certain forms of inflammation where the disturbance of nervous action seems to be the essential feature. The occurrence of an acute peripheral gangrene soon after certain traumatic or inflammatory lesions of the brain or spinal cord, of articular inflammation following chronic affections of the cerebro-spinal axis, are instances in point. The origin and distribution of herpes zoster, the occurrence of sympathetic ophthalmia and symmetrical gangrene, suggest a predominant disturbance of innervation as the exciting cause. At the same time, it is desirable to call attention to the recent observations of MacGillavray, Leber, and others,[15] which suggest that a sympathetic ophthalmia is due to the extension of a septic choroiditis along the lymph-spaces of the optic nerve. It is further apparent that in certain so-called trophic inflammations, as the pneumonia after section of the pneumogastric, and the inflammation of the eye following paralysis of the trigeminus, the paralysis of the nerve is a remote, rather than an immediate cause, of the inflammation. There still remain, however, a number of localized inflammations whose origin is so intimately connected with nervous disturbances as to demand, for the present at least, a corresponding classification. [Footnote 15: Wadsworth's "Report of Recent Progress in Ophthalmology," _Boston Medical and Surgical Journal_, 1882, cvi. 517.] The course of an inflammation is often indicated by the predominance of certain symptoms, which, for the most part, indicate a condition of the individual acted upon rather than a peculiarity of the cause. The sthenic inflammations take place in robust individuals with powerful hearts and an abundant supply of blood. In such persons a strong pulse, high fever, and an injection of the superficial blood-vessels suggested, in former times, the necessity of bloodletting as the essential therapeutic agent. The sthenic form of inflammation was most commonly associated with pneumonia, where the obstruction to the passage of blood through the lungs was an important cause of the superficial injection of the blood-vessels. The asthenic inflammations, on the contrary, are those occurring in feeble individuals, debilitated in consequence of pre-existing disease, exposure, or habits. A weak heart, low febrile temperature, and {47} superficial pallor, characterize the asthenic inflammations, which show a frequent tendency to become localized in the more dependent parts of the body, the force of the circulation being too feeble to overcome the effect of gravitation.