The arm hangs loosely by the trunk, with the forearm semi-pronated. The arm cannot be raised, nor can the forearm be bent on the upper arm. Extension is unaffected, as the triceps is never involved. Supination is impossible because of paralysis of the supinator brevis. Movement effecting rotation of the shoulders is involved, due to the paralysis of the supra- and infra-spinatus. Electrical reactions are said to be less marked in the brachial than the antibrachial type, and complete loss of faradic contractility is rare; but in one of the three cases described below, in which electrical reactions were carefully tested, the right deltoid showed entire loss of contractility to faradism. 3. _Aran-Duchenne Type._--The muscles of the thenar and hypothenar eminences and interossei are affected. This type of lead paralysis may be distinguished from progressive muscular atrophy by the electrical reactions, and the fact that the atrophy is accompanied by more or less pronounced muscular paralysis. The atrophy is almost always most marked, and advances pari passu with the paralysis. This form may occur alone, or be complicated with the antibrachial type, which is the most common. It is seen in file-cutters as the result of overstrain of the muscles in question. Moebius[9], in his observations on file-cutters, noted in one case paralysis of the left thumb, with integrity of the other muscles of the left upper extremity. Opposition of the thumb was very defective; there was paralysis of the short flexor and of the adductor and atrophy of the internal half of the hypothenar eminence. Reaction of degeneration was noted in the muscles named, but not in the extensors of the fingers and wrist. In another case, in addition to feebleness of the deltoid, flexors of forearm on the upper arm, and small muscles of hand, there was paralysis and atrophy of the adductor of the thumb and first interosseous and paralysis of the opponens. 4. _Peroneal Type._--This is a rare type, and nearly always associated with the antibrachial or with generalized paralysis. In the former the paralysis is slight, especially when it affects the psoas; but there is predilection for certain groups of muscles, especially the peroneal and extensor of the toes, while the tibialis anticus escapes. Hyperæsthesia, or more rarely anæsthesia, precedes the onset.