RESPIRATION 



111 



(5) Take a lateral ninth-rib stethogram while the subject reads a 

 paragraph, sighs, coughs, and laughs. Account for the peculiarities. 



(6) Take a lateral ninth-rib stethogram after the subject has 

 taken vigorous exercise. What changes are to be noted? 



(7) Compare the stethogram from several individuals. Determine 

 the essential features and give causes of these. 



(8) Seek the causes of the differences which exist between stetho- 

 grams of different individuals. May they be accounted for by 

 stature, condition, occupation, or habit? 



3. Observations. With the chest pantagraph. The purpose of 

 this instrument is to record the outline of any horizontal section of 

 the thorax, though it could be used as well for tracing the periphera 



FIG. 59 



The chest pantagraph. For measuring and recording chest contours. The instrument is 

 constructed of brass or of wood with brass or steel semicircle. The joints a, 6, x, and y move 

 easily in the plane of the instrument. The semicircle, forty inches in diameter, rotates at x 

 around the dia meter t x. The point / is fixed to a table. With / a fixed point all movements of t, 

 the tracing point, are accompanied by corresponding movements of r, the recording point. The 

 triangle/ r 6 and ft a are similar triangles in all positions of the instrument fb:fa : :fr :ft; 



but j- = _ ; therefore the distance fr is always J /s the distance ft. 

 J a 5 



of the abdomen, of the head, or of the limb. To use the pantagraph 

 for the purpose here intended, let the subject sit beside a table adjust- 

 able as to height. Make such adjustment as to bring the circum- 

 ference of the thorax to be observed even with the upper surface of 

 the table. Fix the point / of the instrument to the table. Let the ob- 

 server locate, with pen or pencil, upon the side of the subject distal from 

 the table, a point which shall serve as a starting point. (See Fig. 59.) 

 When the point (t) of the instrument rests upon this point of the 

 subject's thorax the instrument should be well extended, somewhat 

 more than represented in the figure. Fix a sheet of paper to the 

 table under the recording pencil at r. To take a graphic record of 

 the contour of the thorax proceed as follows: 



, 



