I920 



DISEASES OF THE DUCTLESS GLANDS 



th37roid system McCarrison points out that they are three in number 

 — viz. : — 



A. Nutritional.- — Defective and improper foods. 



B. Infective.- — Insanitary surroundings, bacterial and other 

 toxins, infectious disease, constipation, intestinal stasis, and their 

 associated toxaemias. 



C. Psychical. — Fright, grief, worry, consanguinity in marriage, 

 and heredity. 



He shows that these factors can produce more or less hyperplasia 

 in the gland, followed by fibrosis and atrophy, and that during this 

 there is an alteration in the quantity and quality of the secretion 

 passed into the blood. 



He divides the hyperplasias into two groups. In the first he 

 places those of endemic areas due to a specific infecting agency, such 

 as endemic goitre, slight hypothyroidism, and he shows that these 

 conditions in the parent may become congenital goitre, hypothy- 

 roidism, endemic cretinism, cretinous idiocy, with deaf-mutism 

 and tetany in the descendants. 



In his second group he places such hyperplasias as are due to 

 toxaemia or thyroiditis, and as such he mentions simple toxaemia, 

 goitre, and slight hypothyroidism as one section, myxoedema as a 

 second section, and Graves' disease as a third section; and these 

 occurring in parents may produce much the same results in the 

 descendants as in the first class, but in this condition it will be 

 sporadic and not endemic cretinism. 



Diseases of the th5/roid gland are quite common in parts of the 

 tropics with which we are acquainted. Myxoedema has been seen 

 by us in Ceylon, but is rarer in the tropics than in the Temperate 

 Zone; goitres, parenchymatous and adenomatous, have been met 

 with by ourselves in Ceylon and in Africa, and by Singer in Abyssinia. 

 Exophthalmic goitre has been especially noted as far from rare 

 by Singer in Abyssinia and £mile in East and Central Africa, but 

 is very rare in India and Ceylon. 



ENDEMIC GOITRE. 

 Synonym. — Endemic thyromegaly. 



Goitre is much more prevalent in the tropics than has been 

 realized hitherto, and we have met with it frequently in Ceylon and 

 Africa. 



Climatology. — It is a cosmopolitan disease which, though fre- 

 quently met with in hilly districts, is also, in our experience, quite 

 common in low-lying lands. It does not appear to be associated 

 with any geographical or geological condition. 



iEtiology. — The general tendency of the present time is to con- 

 sider that goitre is a parasitic disease, and this view has been 

 strengthened by the recent important experiments of McCarrison on 

 men and Bircher on rats, which, together with the previous ones of 

 Lustig, Grassi, and many others, tend to show that the causal agent 



