That the ductless glands are closely related holds good also for the thyroid and adrenals. This relation, however, is an antagonistic one. The adrenals increase the blood-pressure (Oliver and Schäfer[12]), and the thyroid diminishes it. It is an interesting fact, demonstrated by Professor Eiselsberg[13] in Vienna, that extirpation of the thyroid gland of dogs results in atheroma of the aorta. In connection with this we also mention the clinical fact, that all those agencies which are harmful to the thyroid gland, as syphilis, abundant meat food (Breisacher,[14], Blum,[15] Lorand[16]), alcohol (Hertoghe and de Quervain[17]), and tobacco (Hertoghe), are also those which are commonly considered to be the causes of high tension and arteriosclerosis. Infectious diseases are also brought in etiological relationship with arteriosclerosis, and it has been shown by a series of authors, that in infectious diseases the thyroid undergoes important alterations which may involve its degeneration (Roger and Garnier, Crispino, Torri, Bayon, de Quervain). Footnote 12: Oliver and Schäfer: Journal of Physiology, vol. xviii, 1895. Footnote 13: Eiselsberg: “Die Krankheiten der Schilddrüse,” Stuttgart, 1901. Footnote 14: Breisacher: Archiv für Anat. und Physiologie, Suppl., Bd., p. 509, 1890. Footnote 15: Blum: Virchow’s Archiv, p. 495-514, 1899. Footnote 16: Lorand: Transactions of the Path. Society of London, vol. lvii, Part. 1, 1906. Footnote 17: La Semaine Médicale, 1905. Infectious diseases also induce changes in the adrenals, as shown by many authors (see Chapter III). Various toxic products, such as lead, alcohol, and tobacco, which are considered causes of arteriosclerosis, are also able to produce hypertrophy of the adrenals. And, if we consider those agencies which are commonly considered the causes of premature senility, we notice the singular fact that they are also considered to be especially harmful to the various glands with internal secretion, particularly the thyroid and sexual glands. Among these agencies may be mentioned infectious diseases, sexual excesses, frequent pregnancies, strong emotions continued for a long time, such as grief and sorrow, chronic intoxications (by poisonous products produced in the body, or introduced from without). We will show later, in an exhaustive way, the action of these agencies upon the glands with internal secretion.