A factor of degeneracy as related to soil on which much stress has been laid, is that of goitre. This has been carefully studied by Munson[176] among the Indians on the reservation in the United States. The number was 77,173, of whom 2·36 per cent. had goitre. As regards geographic distribution the disease is more prevalent in the southern part of Montana. Goitre was reported as practically unknown among the white settlers living about the reservations where goitre was prevalent among the Indians. Fully 80 per cent. of the cases occur in Indian women, the disease being not only much less frequent, but also less decided and less extensive in the male. The average age of onset of the disease was from 12 to 14 years. There are many instances illustrating the apparent heredity of goitre. Several consecutive generations show its development. Only one case is reported in which goitre was associated with cretinism. Goitre among Indians cannot be traced to high altitudes, climate or water containing excess of calcium magnesium salts. The disease is apparently due to insanitary surroundings, depressing constitutional conditions, improper and excessively nitrogenous diet. This condition of things among the Indians bears an important relation to the facts pointed out by C. K. Clarke,[177] of Kingston, Ontario, who found in the Canadian asylums a large number of goitrous patients and one goitrous attendant. The goitrous patients, who were of long residence, had come from all parts of the dominion. The size of the goitre was in proportion to the length of the residence. It is possible that local influence may have much to do with the disease, though it is evident that the insane are much more liable to it than normal persons. W. B. Fletcher, of Indianapolis, has observed similar frequency as to goitre among the insane there, especially among the foreigners and their immediate descendants. Cretinism, according to Morel, was degeneracy due to a special action which a toxic principle exercises on a cerebro-spinal system, whether by the air that is breathed or by the substances ingested in the economy, and which, above all, appears to have some relation to a soil where predominates the magnesian limestone. That the last factor has some influence is shown by the fact that goitrous enlargements are encountered in medical practice in Chicago much more frequently than among the corresponding classes in the East. The water in Chicago contains magnesium-lime salts, whether it be derived from the lake or from the artesian well. The fact, however, that the Indians and the insane exhibit a tendency to goitre indicates that behind the influence of the soil or of diet lies a neuropathic constitution, whether this be inherited or acquired. Cretinism is much more frequent in the United States than was apparent ere the discovery of the value of the thyroid glands in treatment. Under the stimulus of investigation for cases