122 LABOR A TOR Y GUJDE IN PHYSIOLOG Y. 



change the relative lengths of the lever- arms to avoid 

 too great an excursion of the writing point of the 

 lever. 

 (4") Observations. 



(14) How many millimeters will the point of the 

 lever rise or fall for every centimeter that the girth 

 increases? 



(15) What is the average expansion of the thorax 

 during normal quiet breathing? 



(16) During five minutes 75 or 80 respirations are 

 all of the respirations practically the same or are 

 there occasionally deeper breaths? If the latter is 

 observed is there any regularity in the occurrence 

 of deeper respirations ? How may occasional deep 

 respirations be accounted for? 



(17) Let the subject make a series of forced respira- 

 tions. What is the maximum expansion ? What is 

 the average expansion of the series? 



d. The stethogoniometer. 



This instrument is described in Appendix A 13. Its 

 purpose is to record the outline of any horizontal 

 section of the thorax, though it could be used as well for 

 tracing the periphera of the abdomen, of the head, or of a 

 limb. To use the stethogoniometer for the purpose here 

 intended let the subject sit beside a table upon a 

 stool adjustable for height. So adjust the stool as to 

 bring the circumference of the thorax to be observed 

 even with the upper surface of the table. Fix the 

 point c, 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. % 



When the point b, of the instrument, rests upon 

 this point of the subject's thorax the instrument 



