2. German Retrospect

Extract

Professor A. Pick, of Prague, has a paper of fifty pages on the so-called muscular consciousness of Duchenne (“Zeitschrift für Psychologie und Physiologie der Sinnes-organe,” 8 October, 1892). This seems to consist of a knowledge of the position of the limb and of the force of the muscular contractions expended to produce a designed movement. There must also be in the mind a conception of the designed movement. When through anæsthesia a person is unaware of the position of his limbs, he cannot, without the use of his eyes, ascertain where his limbs were when the movement began, and what point they had reached in a given time. He thus must use his eyes to guide the motions of his limbs. This assistance of the visual sense is generally afforded more or less in all complicated movements, even where the cutaneous and muscular sensibility are intact. The visual and muscular senses act together and support one another. We may execute movements with the aid of the cutaneous and muscular sensibility alone as in the dark, and, on the other hand, we may execute movements guided by sight alone. In 1848 Dr. Duchenne made observations upon three patients in whom there was a complete loss of cutaneous sensibility. He found that, when these patients were hindered from seeing their own limbs, they had lost the capacity for voluntary motion. On the attention being diverted from the execution of the designed movement, even when the eyes were left open, the movements were arrested, or were performed in an embarrassed manner in proportion to the degree of distraction. Such extensive anæsthesia is a rare affection. It sometimes follows severe epileptic attacks, or it may supervene after chronic epilepsy, or alcoholism complicated with fits. Sometimes in addition to the loss of cutaneous sensibility there is the suppression of taste and smell, and concentric narrowing of the field of vision. Sometimes the anæsthesia is confined to one side, or to one region of the body, and in such cases the phenomena of transfer have been observed. It is thus a functional affection occasionally attending hysteria. Drs. Thomsen and Oppenheim have minutely described eighteen cases of sensory anæsthesia occurring amongst lunatics (“Ueber das Vorkommen und die Bedeutung der gemischten sensorisch sensibeln Anæsthesie bei Geisteskranken.” “Archiv für Psychiatrie,” xv. Band, 2 Heft, and xvii. Band, 2 Heft.)