Sunlight and health / by C.W. Saleeby.

  • Caleb Saleeby
Date:
[1923]
Catalogue details

Licence: In copyright

Credit: Sunlight and health / by C.W. Saleeby. Source: Wellcome Collection.

    37/202 page 19
    monthly height of the sun in New York. By radio - graphic study of the bones of infants, it had also been shown that no new cases of rickets occur in New York in June-July, and the maximum number occur in March. Dr. Hess now informs me that the calcium content of the blood follows the same curve as the phosphorus content. Among earlier noted seasonal effects of sunlight, quoted by Hess in his latest paper, axe the presence of increased iodine in the thyroid of cattle from June to November, and the greater resistance of guinea-pigs to aceto-nitrile poisoning in summer. Hess and his workers have also begun the study of various clothing materials in this connection, and find that they vary in their power of permitting or obstructing the action of light. Specimens of a mercerised cotton, one white and the other black, but otherwise identical, the former allowing light to act and the latter interfering with it, have been examined by me, and I find no difference, due to the black dye, in the spacing between the fibres of the material. But I understand that the Department of Applied Physiology of the Medical Research Council has found, in a series of observations as yet unpublished, that the biological action of light can be graded by temperature. I am glad that these specimens of material are now being studied by the delicate methods associated with the name of Professor Leonard Hill, and think it may be found that the black material produces a higher temperature than the white of the subjacent skin, thus prejudicing those unknown and beneficent chemical reactions which appear to need
    digitised image 1
    digitised image 2
    digitised image 3