With regard to the action of potassium iodide, there is division of opinion amongst various physicians as to the efficacy of the drug in the elimination of lead from the body. At the same time a very large number of persons hold that the administration of fairly large doses of potassium iodide in the case of a person suffering from chronic lead absorption may at times be associated with sudden exacerbation of the disease, and that the drug apparently may determine the production of acute symptoms, such as encephalopathy or paralysis, when these have not been previous features of the case. Our experience supports this statement, and on more than one occasion one of us (K. W. G.) has seen a distinct increase of symptoms follow the administration of large doses of potassium iodide. From a comparison with other cases it seems that these symptoms would have been unlikely to make their appearance without some secondary cause. Against this point of view must be quoted further experiments already referred to by Zinn[9], who found that when lead iodide was administered to experimental animals iodine alone was found in the urine; but it must be pointed out that no estimations were made of the fæces, and it is possible that a certain amount of lead was eliminated in this way. What exactly is the action of iodide on the solubility of lead in the body it is difficult to say; yet the use of iodine compounds has been followed with considerable success in a number of chronic inflammatory diseases, and it is possible that it may have the action of splitting off the particular lead compound from its organic association with the tissues, especially as it is well known that iodine plays a very important rôle in the process of cell metabolism. Another point which tends to support the use of iodine is the fact that the other two halogens, bromide and chloride, both of which enter largely into cell metabolism, also have a slightly beneficial effect on the excretion of lead. The dose of the iodine given should not be large to commence with, 3 grains three times a day is sufficient, the dose being run up to some 30 or 40 grains per diem, the symptoms meanwhile being carefully watched. Other symptoms often associated with the anæmia of lead poisoning are-- _Rheumatic Pains._--These pains are suggestive of muscular affection, and are possibly due to minute hæmorrhages occurring in the muscle tissue, which have been discovered in the muscles of experimentally poisoned animals. For the rheumatic pains diaphoretics and citrates of soda and potassium may be given. _Lumbago._--The lumbago constantly complained of in chronic lead poisoning and even in the early stage of lead absorption, is very generally related to chronic constipation rather than to a definite affection of the lumbo-sacral joints.