80 SPECIAL PHYSIOLOGY 



Study the new instruments and make drawings and diagrams 

 showing their construction. 



2. Preparation. Let a student remove the clothing from the 

 chest. Find the apex beat. In which intercostal space is it located ? 

 How far is it to the left of the middle of the sternum? Is the loca- 

 tion of the apex beat the same for all members of the class? In 

 recording the location of the apex beat refer to the bony landmarks 

 of the chest rather than to the nipple. 



To take a cardiogram place the button (cork) of the receiving 

 tambour upon that point of the thorax most affected by heart beat. 

 The movements of the apex of the heart will be transmitted and 

 magnified by the cardiograph. Trace a cardiogram upon the 

 kymograph. 



3. Observations. (1) Take several cardiograms from the same 

 individual, being careful so to adjust the apparatus as to gain the 

 maximum excursion of the lever. What features have all of these 

 tracings in common? What features seem to be accidental and 

 non-essential ? What are the causes of the essential features ? W T hat 

 are the sources of the non-essential features? 



(2) Take cardiograms of several individuals. Do all of them 

 possess the features which seemed essential in the first series, taken 

 from one individual? If not, how would you account for the differ- 

 ence. 



(3) With a stethoscope, whose construction you have carefully 

 described in your notes, listen to the heart sounds while the cardio- 

 graph is tracing the record of the heart movements. Note that two 

 sounds are audible and that there is a notable pause following the 

 shorter, sharper sound; let us call the sound which succeeds the 

 pause the first sound. 



(4) With what part of the cardiogram does the first sound seem 

 to correspond ? With what part of the cardiogram does the second 

 sound seem to correspond? Give reasons for this correspondence. 



(5) As far as the data will admit, enumerate causes for the first 

 sound; for the second sound; for the essential features of the cardio- 

 gram. Can one locate on the cardiogram that crest or feature which 

 corresponds to the auricular systole? The ventricular systole? The 

 recoil of the ventricles? The closure of the semilunar valves? The 

 opening of the semilunar valves? 



(6) Giving full attention to the auscultation of the cardiac region 

 of the chest with the stethoscope, note carefully: (a) The point 

 where the first sound is most distinctly heard. Locate this point 

 with reference to the thoracic skeleton. (6) The point where the 

 second sound is most distinctly heard. Locate same with reference 

 to skeleton. 



(7) Compare the two sounds as to duration, intensity, pitch, and 

 quality. 



