1237 



lower than the former; and al last a seooiid descending pait that 

 ends in an expiration of the lungs. We know for ihe lesl that the 

 number of snch like finotnations is very variable, and ft r simplicity's 

 sake only one has been represented. 



These tlnctnations of the month-bottom are accompanied by 

 modifications of the pressnre in the inonlh which is alternately above 

 and below the zero-point, and amonnis at the utmost to a few 

 millimeters of water. Conseqnently these movements are cansed by 

 active movement of the mnscles, and are the factors of the bucco- 

 pharyngeal ventilation. 



At the same time the graphical representation of the pressure in 

 the lungs shows little fluctuations presenting an opposite direction 

 to that of the diagram K. Since Graham Brown it is generally 

 admitted that they are bi'ought about by the contraction resp. 

 expansion of the lungs on account of the displacement of the larynx. 



In a subsequent essay I intend to communicate the variations of 

 the typical movement-complex. 



