316 LABORATORY GUIDE LV PHYSIOLOGY. 



showing location of pulleys, (b) A section of thorax 

 showing belt in position. The cord is tied to an eye in 

 pulley No. 1, passes around the circuit of pulleys to No. 1 

 again, thence over two or three pulleys which serve to 

 change the direction, bringing the cord finally to a record- 

 ing lever adjusted as described for the thoracometer. 

 (c) Showing an enlarged view of a pulley. The brass 

 base of each pulley is fixed to a piece of sole leather 4 or 5 

 cm. long by 3 or 4 cm. wide. Copper wire, riveted at the 

 points r and r', clasps the elastic belt and holds the pulley 

 in position. 



13. The stethogoniometer. 



Various methods have been employed for determining 

 the curvature of the chest wall. Even so simple a method 



FIG. 60. 



FIG. GO. The Stethogoniometer used in graphically recording any 

 perimeter of the thorax. 



as the taking of several diameters will reveal approx- 

 imately the general conformation of the chest wall. A 

 graphic method has this to recommend it : that a glance at 

 an outline of any circumference of the thorax reveals more 

 than any amount of time expended in the study of numer- 

 ical data. Of all the graphic methods used by the writer 

 the one here described seems most simple and practical. 

 The accompanying figure (Fig. 60) shows the instrument, 

 which will be recognized as similar to a draftsman's pan- 



