If three such periods can be recognized, as no doubt they can, as divisions of the time during which lead gradually affects the tissues, the symptoms in the more severe cases would be expected to be those associated with the more prolonged exposure. This, no doubt, is true to a limited extent, more particularly in industrial poisoning, depending for its development on a long-continued dosage of lead in minute quantities, and for the most part of metallic lead. On the other hand, with some of the salts of lead, notably the hydrated carbonate, acute disease may take place during the first stage--namely, impregnation of lead--the determining factor then being either the retardation of the elimination of lead, or a suddenly increased quantity in lead dosage, or some intercurrent disease, or even alcoholic excess, whereby a sudden large excess of the poison is thrown into the general circulation. The commonest type of paralysis occurring is the one affecting the muscles of the hands, which may for a considerable time show some diminution in their extensor power before the actual onset of the disease takes place. The onset of paralysis is practically always unaccompanied by pyrexia; the only occasions in which pyrexia may be associated with the onset of the attack are those cases in which some secondary cause determines the paralysis, and the pyrexia in these instances is due to the intercurrent disease, and not to the lead infection. Although weakness of the extensor muscles of the hands may be present in persons subjected to lead absorption for a considerable time, the actual onset of the disease itself is frequently sudden; but in the majority of cases it is distinctly chronic, and is rarely, in the case of paresis, associated with any definite prodromal symptoms. Prodromal symptoms have been noted, such, for instance, as lassitude, general debility, and more especially loss of weight. Cramps of the muscles the nerve-supply of which is becoming affected, alteration of the skin over areas corresponding to definite cutaneous nerves, hyperæsthesia, anæsthesia, or analgesia, may occasionally be present. Neuralgic pains have also been described, but these are inconstant, and generally of the arthralgic type related to the periarticular tissues of joints rather than to pain in the course of the nerves. The pain is rather of the visceral referred type than a definite neuralgia. Tremor is, however, frequently associated with the preliminary condition of paresis, and in several cases variations in the amount of weakness of the extensor muscles of the wrist have been noticed, as far as can be estimated clinically without the use of a dynamometer. Associated with this weakness is tremor of a fine type, often increased by movement (intention tremor), and in every case more marked during the periods of increased weakness. Instances have occurred where definite wrist-drop followed after a prolonged period of weakness; in others the weakness