120 LABORATORY GUIDE IN PHYSIOLOGY. 



(4) Take a stethogram of the dorso ventral diameter 

 of the thorax over the lower end of the gladiolus. 

 Compare. 



(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 sub- 

 ject has taken vigorous exercise. What changes 

 are to be noted ? 



(7) After a similar series of stethograms have been 

 taken for others, compare; determine the essential 

 features; give causes of these. 



(8) Seek the causes of the difference which exist be- 

 tween stethograms of different individuals. May 

 they be accounted for by stature, condition, occupa- 

 tion or habit? 



b. The thoracometer. Remove from the stethograph 

 the wooden rod which bears the receiving tambour, 

 and slip the iron rod of the apparatus described in 

 Appendix A- 11 into the same place with the button 

 inward. The accuracy of the apparatus is increased 

 if the heavy support which bears the spiral spring, 

 just fixed in position, bear also the recording lever. 

 Use a simple myograph lever which may be clamped 

 to the support. The cord which runs over the pulley 

 beneath the spring must change direction at least 

 twice after leaving the first pulley. One will need 

 two more pulleys such as the one described in the ap- 

 pendix. They may be held in position by clamp 

 holders. If one use a horizontal drum, however, the 

 cord may pass from the first pulley direct to the lever. 

 In either case one would need to pass an elastic band 

 around the short arm of the myograph lever in such a 

 way as to draw the lever in a direction opposite to that 



