29 JANUARY 1927, Page 18

NVhat is the vis medieatrix naturae ? Perhaps we shall

never know, unless we solve the secrets of life itself. But Dr. Saleeby, whose third edition of Sunlight and health (Nisbet, 5s.) is just out, gives us some illuminating thoughts on " Modern Sun-Worship," and kindred subjects which every parent and every teacher should read. Indeed, everyone who would be healthy should read this remarkable book. Soon we shall all be practising heliotherapy, says Dr. Saleeby, and he adds that Rollier's must be our text hook. By the same post Dr. Rollier's Heliotherapy (Oxford University Press, 20s.) has arrived. It is too technical for review. in these colurrins, but it is the splendid record of two deCides of one of the greatest works in the modern world.

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