The symptoms of _chronic_ poisoning by arsenic are loss of appetite, silvery tongue, thirst, nausea, colicky pains, diarrhoea, headache, languor, sleeplessness, cutaneous eruptions, soreness of the edges of the eyelids, emaciation, falling out of the hair, cough, hæmoptysis, anæmia, great tenderness on pressure over muscles of legs and arms, due to peripheral neuritis, and convulsions.
Pigmentation is common; the face becomes dusky red, the rest of the body a dark brown shade. This darkening is most marked in situations normally pigmented and in parts exposed to pressure of the clothes, such as the neck, axilla, and inner aspect of the arms, the extensor aspects being less marked than the flexor. The pigmentation resembles the bronzing of Addison's disease, but there are no patches on the mucous membranes, and the normal rosy tint of the lips is not altered. The skin over the feet may show marked hyperkeratosis.
The nervous system is notably affected. The sensory symptoms appear first: numbness and tingling of the hands and feet, pain in the soles of the feet on walking, pain on moving the joints, and erythromelalgia. Then come the motor symptoms, with drop-wrist and drop-foot. The patient suffers severely from neuritis, and there may be early loss of patellar reflex. The nervous symptoms come on later than the cutaneous manifestations.
_Post-Mortem Appearances._--Signs of acute inflammation of stomach, duodenum, small intestines, colon, and rectum. Stomach may contain dark grumous fluid, and its mucous coat presents the appearance of crimson velvet. Ulceration is rare, and cases of perforation still less common, the patient dying before it occurs. If life has been preserved for some days, there is extensive fatty degeneration of the organs. There may be entire absence of _post-mortem_ signs. Putrefaction of the body is retarded by arsenic.
_Treatment._--The stomach-pump, emetics, then milk, milk and eggs, oil and lime-water. Inflammatory symptoms, collapse, coma, etc., must be treated on ordinary principles. As an antidote, the best when the poison is in solution is the hydrated sesquioxide of iron, formed by precipitating tinctura ferri perchloridi with excess of ammonia, or carbonate of soda. This is filtered off through muslin and given in tablespoonful doses. It forms ferric arsenate, which is sparingly soluble. Colloidal iron hydroxide may be used instead. Dialyzed iron in large quantities is efficacious.