From “Laboratory manual for physiology of exercise”, by Laurence E. Morehours, Published by C.V. Mosby, 1972, page 98.

Although this photo was published in a 1976 textbook, this device is probably from the 1950’s or earlier.  Used to measure oxygen and carbon dioxide by an absorption technique.  From Medical Instrumentation for Healthcare, by Cromwell L, Arditti M, Weibell FJ, Pfeiffer EA, Steele B, Labok J.  Published by Prentice-Hall, 1976.  Page 270.