1'L.VTK XCV. 



FIG. 250. Boxwood Pulley for recording the movements of a neeV'e., inserted in the diaphragm- A light lever 

 is attached to the horizontal arm ( 91). 

 FIG. 251. Bosenthal's apparatus, with W. Mailer's valves ( o6. 



KK;. 252. ivtt<-nk.,f,. 



