Of late years pathologists and medical men, especially those who are interested in children's diseases, have devoted considerable time to the study of certain cases of sudden death, which have long been very mysterious. Infants often die while in apparent good health without any adequate reason that can be found, even on the most careful autopsy. Children of an older growth sometimes die suddenly as the result of some slight shock or fright, or they die after the administration of a few whiffs of chloroform, given to help in the performance of some simple surgical operation, or they die at the beginning of some infectious fever which they ought to be able to withstand without any difficulty. A distinguished pathologist at Vienna, Professor Paltauf, who was the coroner's physician of the city and had a large number of these sudden deaths to investigate, found that in most of the cases one abnormal condition was constantly present. This consisted in an enlargement of the lymph glands all over the body. The lymph glands in the neck were involved, also the tonsils and lymphoid tissue at the back of the throat, the series of lymph glands in the groin, and, finally, there was a hypertrophy of the lymphoid tissue that occurs all along the intestinal tract. This condition of hypertrophy of lymphoid tissue has come to be known as the lymphatic diathesis or constitution. It is nearly always accompanied by a distinct hypertrophy of the thymus gland. The thymus gland is an organ which occurs in the upper part of the thorax of the child, but which atrophies and practically disappears after the age of two years. In these cases it is from twice to three {158} times its normal size in the infant, and in older children it is persistent--that is, retains its primary size, though in the ordinary course of nature it should atrophy. This lymphatic diathesis undoubtedly has considerable to do with the sudden deaths which occur in these patients. What the exact connection is we do not as yet definitely know. Unfortunately, moreover, this lymphatic constitution gives no sure sign of its existence before the occurrence of the fatal termination. Enlargement of the glands of the neck and of the groin, with some enlargement of the tonsils, occurs in delicate children without necessarily being symptoms of the lymphatic diathesis. The enlargement or persistence of the thymus can be better recognised, and doctors now seldom fail to notice it. Where any suspicion of such a condition exists in children of from eight to sixteen or seventeen years of age, proper precautions must be taken to prevent sudden fatal termination of any even mild disease without due preparation. Undoubtedly many of the cases of sudden death under chloroform and ether in children and young persons are due to the existence of this lymphatic diathesis.