If you are familiar with many of the light therapy arguments today this should make you smile; I stumbled across a book published in 1946 called Electrotherapy and Light Therapy and I quite enjoyed the cautious speculation and many accuracies that we still discuss today.
The book is 694 pages long, the section on light and infrared therapies is 26 pages, here some samples for you.
Thank you for posting this historical excerpt! Enjoyed it very much.