160 PHYSIOLOGY CHAP. 



fluid bolus is shot into the stomach by the contraction of the 

 striated muscles, before peristalsis of the oesophagus can take 

 place. Manonietric observations show that at the commencement 

 of the act of deglutition there is a rapid increase of pressure equal 

 to about 20 cm. water near the base of the tongue, and also in the 

 gullet, but not in the stomach. 



Meltzer performed an interesting series of experiments on 

 himself, to prove that this increased pressure in the retro-buccal 

 space at the commencement of deglutition suffices to drive the 

 bolus rapidly into the stomach. When a sound w r ith a very light 

 rubber balloon at one end (see Vol. I. fig. 192, p. 429), and a 

 recording tambour at the other, is passed down the oesophagus to 

 various measurable depths, two elevations are marked on the 



FIG. 53. Curves of deglutition obtained from himself by Meltzer, on introducing two separate 

 sounds into pharynx and oesophagus. F, tracing from pharyngeal sound ; K, tracing from 

 oesophageal sound, passed 4 em. down the oesophagus ; s, time tracing in seconds. A little 

 liquid was swallowed at A ; more at B ; a large amount at C. 



rotating drum at each act of swallowing, which Kronecker terms 

 " signals of deglutition " (Schluckmarken) : the first signal appears 

 immediately after the act, independent of the depth to which the 

 sound lhas been introduced into the oesophagus ; the second, on 

 the contrary, appears later in proportion as the sound goes 

 deeper. On introducing a second sound into the pharynx, and 

 repeating the above experiment, Kronecker and Meltzer obtained 

 the curves of Figs. 53 and 54. 



The rapid rise of the curve from the pharyngeal sound of 

 Fig. 53 signals the moment at which the bolus (or liquid mouthful) 

 shoots down the pharynx, and compresses the balloon. A, B, C 

 show that the height of the elevation is in proportion with the 

 amount of fluid swallowed. The oesophageal tambour marks no 

 rise at A to coincide with that of the pharyngeal tambour, owing 

 to the small amount of water swallowed ; but at B and C the 

 passage of the fluid into the oesophagus is clearly signalled by 

 elevations which coincide with those of the pharynx. All three 



