NERVOUS SYSTEM.—Therapeutic doses stimulate, while large or toxic doses depress or even paralyze, the nervous mechanism. The sensory apparatus is usually the first affected, the reflex and motor following in order. The reverse may occur. Authorities agree that ar senic acts directly upon the nerve-centres through changes in the cell-elements.
Three cases of arsenical neuritis, the third being especially interesting be cause the left upper extremity only was involved. It is uncommon to see in volvement of but one extremity, and apparently the left upper extremity has been reported but once as being involved alone. A study of the literature clearly demonstrates that arsenical neuritis is most frequently due to acute intoxication with arsenic. Series of 253 cases, of which 136 were due to acute poisoning. The condition most fre• quently involves the lower extremities, and the peripheral parts—viz., the feet, the hands, and the lower part of the That the long-continued use of arsenic affects the peripheral nerves is certainly proved by the presence of a wide-spread multiple neuritis in many cases of chronic arsenical poisoning.
Case of a girl, aged 19, who took by mistake a packet of arsenous acid. Acute symptoms of arsenical intoxication lasted three days. There then super vened symptoms of toxic polyneuritis, which in turn disappeared. Fifteen days later invalid had considerable atrophy of the muscles of the limbs and trunk, motor paralysis, and very pronounced cutaneous and muscular hypermsthesia. Treatment consisted of hypodermic in jections of strychnine, massage, hydro therapy, electricity, and iodide of potas sium, under which the patient gradually improved, but is not yet well. M. Krever (Gaz. Hebdom. de et de Chir., Sept. 15, '98).
Tingling of the fingers, formications, headache, giddiness, and muscular trem ors result from too large a dose of arsenic, while even convulsions may precede the paralysis of a lethal dose. The tendency to give arsenic in large doses, on account of its great value in certain diseases, is leading to the publication of several cases where paralysis has ensued.
Case of girl suffering from chorea who took arsenic in 15-minim doses, given three times a day for 31 days, 'except on C of those days. The chorea was speedily cured, and drug stopped; but 13 days after its cessation she began to suffer from symptoms which ushered in periph eral neuritis and almost complete paral ysis of all extensor muscles below the knees, with well-marked reaction of de generation, and some weakness of the extensor muscles of the forearms. She
had arsenical pigmentation of time neck and the groins; but under treatment by rest, massage, and electricity she rapidly recovered. Colman (Brit. Med. Jour., Jan. 22, '98).
Arsenic interferes with the normal metabolism, but the exact nature of the chemical changes which occur is not understood. While beneficial in very minute doses, in sufficiently large quan tities it may produce inflammation in any part of the body, either applied directly or through the circulation. The stomach may be irritated by direct ac tion, or after the arsenic is absorbed the stomach may become the seat of inflam mation from the arsenic in the circula tion. The arsenic in the circulation reaches all tissues. Almost all of the symptoms are produced by the action of the irritant in this manner. There can be but little or no doubt that the cause of the recent Manchester epidemic was due to arsenic, because there was an absence of any other sufficient cause; sufficient arsenic was discovered to pro duce the symptoms of poisoning; and that the symptoms were identical with those produced by chronic arsenic taken in other ways. T. Lauder Brunton (Lancet, May 4, 1901).
There is no doubt as to the possi bility for evil of small quantities of arsenic taken daily over a period of time. At the same time, there is no doubt as to the great therapeutic value of arsenic in certain morbid conditions, and as to the justification of the con tinuance of the use of this drug in these conditions. Serious chronic arsenical poisoning as a result of the administra tion of this drug is a rarity. The tolera tion of arsenic varies in different in dividuals and under different conditions. Arsenic is of signal value in chorea, malaria, asthma, and chronic heart affections. In the treatment of anaemia it is often combined with iron, but there is no evidence to show that arsenic acts as a hmmatinic tonic. Ralph Stockman (Brit. Med. Jour., Oct. IS, 1902).