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PHYSIOLOGY 



CHAP 



connected with the nasal cavities, he was able to distinguish a first 

 inspiratory depression, due to the systolic lift of the intercostal 

 spaces of the precordial region, from a second, later depression due 

 to meiocardia. This is plain in the two tracings (Figs. 82 and 83), 

 in the first of which the negative pneumograin of the nasal fossae 

 is recorded simultaneously with the sphygmogram of the carotid, 



FIG. 84. jV, Positive pneumogram taken from nostrils with efteft- glottis ; Co, carotid 

 sphygmogram, recorded simultaneously. (Mosso.) 



and in the second with the thoracic cardiogram. Repeating the 

 experiment with closed glottis, the negative pneumogram is trans- 

 formed into the positive (as shown on Fig. 84). All who, like the 

 author, are incapable of holding their breath without closing the 

 glottis, obtain, on the repetition of Mosso's experiment, positive 

 pneumograms only. This was the case (as Mosso points out) with 

 Terne van der Heul (1867), who, on making these experiments 

 under the guidance of Bonders, invariably obtained results that 

 contradicted the above theory. 



If a sound is introduced into the oesophagus, covered at the 



FIG. 85. I, Cardiac sphygmogram from dog, transmitted from oesophageal iexplorer to recording 

 tambour during long expiratory pause; II, effects of cardiac beats transmitted from rectal 

 explorer, recorded simultaneously. (Luciani.) 



end by a very fine rubber membrane like the finger of a glove, 

 the canal is transformed into an intrathoracic cavity communi- 

 cating with the exterior in such a way that (on connecting up 

 the external opening of the sound with a tambour and 

 writing lever) the vibrations produced within the thorax can 

 all be traced on the rotating cylinder. The negative oscilla- 

 tions are recorded by descending, the positive by ascending 

 lines. We were the first, in 1877, to introduce this method into 





