The Collaborative International Dictionary of English v.0.48:

Pneumatograph \Pneu*mat"o*graph\, n. [Pneumato- + -graph.]
   (Physiol.)
   An instrument for recording the movements of the thorax or
   chest wall during respiration; -- also called stethograph.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stethograph \Steth"o*graph\, n. [Gr. ? the breast + -graph.]
   (Physiol.)
   See Pneumatograph.
   [1913 Webster]