31, 1908) prescribes them with much benefit in tuberculosis, rheumatic conditions, obesity, anaemia, neurasthenia, etc.

He considers that their peculiar value lies in the action of light.
Professor J.N.Hyde, of Chicago, even believes ("Light-Hunger in the Production of Psoriasis," _British Medical Journal_, Oct.

6, 1906), that psoriasis is caused by deficiency of sunlight, and is best cured by the application of light.

This belief, which has not, however, been generally accepted in its unqualified form, he ingeniously supports by the fact that psoriasis tends to appear on the most exposed parts of the body, which may be held to naturally receive and require the maximum of light, and by the absence of the disease in hot countries and among negroes.
The hygienic value of nakedness is indicated by the robust health of the savages throughout the world who go naked.

The vigor of the Irish, also, has been connected with the fact that (as Fynes Moryson's _Itinerary_ shows) both sexes, even among persons of high social class, were accustomed to go naked except for a mantle, especially in more remote parts of the country, as late as the seventeenth century.