In a general way it may be stated that lesions of the kinesodic system are characterized positively by the isolated existence or predominance of {72} motor symptoms, by impairment of muscular nutrition, and by De R.; also by contractures. The reflexes are almost never normal, being either exaggerated or lost. Negative symptoms are—absence of sensory symptoms, of ataxia, and of vesical or rectal symptoms. (_a_) Lesions of the anterior gray horns (9) are revealed by most definite and characteristic symptoms. There occurs a flaccid paralysis involving more or less extensive groups of muscles in the extremities, rarely truncal muscles, and never those of organic life. In a few weeks the paralyzed muscles undergo atrophy, sometimes to an extreme degree, and various degrees of De R. are present. Cutaneous and tendinous reflexes are abolished. The bladder and rectum are normal. Sensory symptoms absent, and if present consist only of mild paræsthesiæ, which are probably due to postural pressure upon nerve-trunks or to disturbance of the peripheral circulation. There is no tendency to the formation of bed-sores, but circulation and calorification are reduced in the paralyzed members. It should be remembered that paralysis due to systematic lesion of the anterior gray horns is never typically paraplegic, with horizontal limit-line of sensory symptoms, a cincture feeling, and vesical paralysis. {73} The above symptom-grouping is characteristic of lesion of the anterior horns en masse; in other words, of poliomyelitis. In that form of systematic disease of the anterior horns which consists primarily and chiefly of a degeneration or molecular death of the ganglion cells there is no true paralysis; the atrophy of muscles is infinitely slower, and it proceeds in various muscles fasciculus by fasciculus, the wasting being usually preceded by fibrillary contractions, and being almost always symmetrically located on the two sides of the body (affecting analogous or homologous parts). The electrical reactions are abnormal, in that musculo-faradic reaction is lost in exact proportion to the wasting; so that in a large muscle one part may contract normally, while the adjacent fasciculi do not. It is as yet uncertain whether De R. occur in this disease (progressive muscular atrophy). Calorification and circulation are much less impaired than in poliomyelitis; the negative symptoms are much the same. It is sometimes difficult to distinguish poliomyelitis from generalized neuritis. The diagnosis is to be made by the presence in the latter disease of marked sensory symptoms—neuro-muscular pains, numbness, slight anæsthesia—and by a grouping of symptoms coinciding with the distribution of nerve-trunks and branches. No assistance can be derived from electrical tests, as both diseases yield more or less typical De R.