These changes have been found by Whitwell[90] also in myxœdematous persons. In accordance with these anatomo-pathological changes we must also expect clinical symptoms, and we shall thus find in persons with degenerated thyroids an idiotic condition termed cretinism, while in persons suffering from myxœdema mentality is considerably altered. Thus Pilcz[91] notes as typical symptoms of myxœdema: slowness of thought, apathy, defective memory, and somnolence. In fact, after removal of the thyroid gland or after its degeneration by disease, we observe changes in all those functions which, according to our present knowledge of physiology, are situated in the cortex cerebri, such as intelligence, power of imagination, will power, memory, sleep, etc. The thyroid must govern these functions, as they are seriously damaged after the degeneration of this gland. Thus, myxœdematous people think and speak very slowly, have a weakened intelligence, are completely apathetic, and have no will-power, and the memory is either gone or is defective. In the same way, as in old age, myxœdematous people can remember events which have happened a long time ago, but cannot do so as regards recent events—all facts we explain by assuming they are able to remember what has happened at the time prior to the degeneration of the thyroid; but after such a condition they are not able to mirror recent events in the greater brain. The wonderful effect of the thyroid on intelligence can be observed, as above mentioned, in backward or cretinous children who, by means of the thyroid extract, become intelligent children gifted with a better memory. We, ourselves, through personal observation and experiments, observed the fact that thyroid tablets improve the memory (see also Chapter LIII), and it is interesting to mention here the case of a very stout patient who, after the first day of thyroid treatment, felt in such a condition of mental activity that he sat down, in the middle of the night, at his writing table to compose a scientific article instead of going to sleep. We did not mention to this gentleman—a lawyer—anything about the effects that the thyroid might have. Dr. Hertoghe, the well-known authority on the thyroid gland, told us that he sometimes takes before strenuous mental work, such as the delivery of a lecture, three or four thyroid tablets at a single dose. We must not, however, allow ourselves to be seduced to thyroid medication by the action of thyroid on mentality, unless the condition of our gland demands it, for the administration of such extracts in large doses and without special diet and precautions may produce disagreeable symptoms, a description of which we will give in a special chapter on the treatment of old age by means of extracts from the organs of animals. Footnote 90: Whitwell: British Med. Journal, p. 730, Feb. 1892. Footnote 91: Quoted after Oppenheim: “Lehrbuch der Nervenkrankheiten,” p. 1383, Berlin, 1906.