816 PULMONARY MUCOUS TISSUE. 



ing, have been experimentally verified by Marey, by means 

 of the graphic method. This physiologist has reached the 

 following conclusions in regard to the effect produced on the 

 circulation by respiration. Respiration affects the pulsation 

 of the heart ; it not only causes variation in the line of the 

 whole tracing, but imparts to the pulsations produced during 

 inspiration an amplitude and a form which differ from those 

 observed during expiration; when respiration is stopped, the 

 pulsation of the heart slackens and diminishes in intensity : 

 these modifications are explained by the fact that the blood 

 passes less readily through the lung when the latter is not in 

 action. After an effort (forcible attempt at expiration, the 

 glottis being closed) the pulsation of the heart assumes 

 special features. The left ventricle makes its action intensely 

 perceptible, while the blood in the auricle is violently pre- 

 cipitated at the period at which the diastole begins. If the 

 person experimenting breathe through a narrow tube, the 

 relation between the pulsation of the heart and the respira- 

 tory movements is changed : while the respiration becomes 

 less frequent, the pulsations become more rapid. 



We also find in the pulse differences corresponding to the 

 'different respiratory types (thoracic and abdominal types, see 



. 295). The thoracic type exhibits a diminution of pressure 

 uring inspiration, the whole extent of the line traced rising 

 again during expiration. The abdominal ' type produces 

 exactly the contrary effect (Marey). We give (Fig. 83) a 



P. normal. Inspiration. Expiration. 



Fig. 83. Abdominal type. 



graphic tracing of the pulse, while respiration is taking place 

 during forcible contraction of the diaphragm. We see that 

 in the abdominal type (as in the thoracic) the pulsation 

 diminishes, and, finally, disappears, while the arterial tension 

 increases. 1 



We may mention, in conclusion, and rather as an experi- 



1 P. Lorain, ' Etudes de Medecine Clinique." Le Pouls, 1870. 



