The Problem of Endemic Goitre.

The first is the classical type prevalent in mountainous regions, such as the Alps and Himalayas, occurring as a colloid-poor diffuse parenchymatous goitre in childhood, and as an adeno-parentchymatouts, nodular goitre, with its degenerative forms in adults. The second is the difJuse colloid goitre prevalent in lowland regions, such as the plains of Central Europe, and in England. The geographical limits of these two types are not clearly defined. Both may occur together in the same locality, but in general the former predominates in mountainous and the latter in lowland regions. The former is rarely associated with hyperthyroidism or Graves's disease; the latter is commonly associated with both. The former is usually associated with congenital goitre, cretinism, deaf-mutism, and various grades of physical and mental deterioration; the latter is rarely associated with these congenital manifestations of the disease. The former, in its adenoparenchymatous form, increases in incidence as age advances, attaining to its acme between the ages of 50 and 60 years; the latter is more prevalent about the age of puberty, lessening rapidly or gradually disappearing after the age of 25 to 30 years. Both vary greatly in incidence in different localities. In regions of high endemicity the two sexes are affected in approximately equal proportions. In regions of low endemicity the incidence is higher in females.