Читать книгу Old Age Deferred. The causes of old age and its postponement by hygienic and therapeutic measures онлайн

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As a general rule infants of both sexes look very much alike, so much so, indeed, that sometimes it is only possible, upon close inspection, to determine the difference in sex. This, however, can only be so for a certain period until certain changes take place in the ductless glands, especially in the sexual glands and the thyroid.

The latter contains but very little, if any, colloid substance in infancy, and the colloid increases only gradually until it is present in abundance at the time of puberty, when also the changes in the sexual glands reach a climax coincident with the ripening of the follicles in the ovaries and their rupture at a menstrual period. This latter process is, as we have mentioned before, under the influence of the thyroid. Puberty and menstruation do not take place, as a rule, in persons with a degenerated thyroid gland.

With the onset of puberty there is seen, also, a change in the external appearance of the individual and the attributes of virility—e.g., moustache, hair in the pubic region, alteration of the voice, etc., appear. In the female the development of the breast, hair on the pubis, etc., occurs. At the same time the features attain the peculiar characteristic which distinguishes the male face from the female, even without the aid of a moustache.