162 PHYSIOLOGY CHAP. 



owing to compression from the bolus (solid or liquid), which is driven 

 through the oesophagus by the forcible contraction of the mylo- 

 hyoid muscles; the second is due to the successive contraction 

 of the pharyngeal and oesophageal constrictors of the pharynx 

 and oesophagus. The increased pressure in the mouth determines 

 the rapid propulsion of the bolus (fluid, or solid reduced to a 

 pulp) into the cardia ; the subsequent contraction sweeps away 

 from the gullet any particles of food that are adherent to its walls, 

 and overcomes the resistance of the cardia, driving the bolus into 

 the stomach. 



According to Meltzer, the human oesophagus does not contract 

 by peristalsis, as is usually accepted, but in three sections (the 

 first being 6, the second 9, the third 6-7 cm. long), each of which 

 is emptied successively like the several segments of the heart. 

 When the upper part is in maximal contraction, the lower part 

 begins to contract, so that the solid bolus (which cannot like 

 fluids be directly propelled by the thrust of the mylohyoid 

 muscles) is forced to descend towards the stomach. Meltzer 

 succeeded in determining the interval between the contraction of 

 the mylohyoids and of the pharyngeal constrictors (O3 sec.), 

 between the contraction of the pharyngeal constrictors and that 

 of the first section of the oesophagus (O9 sec.), between the 

 contraction of the first and second sections of the oesophagus 

 (1'8 sec.), between the contraction of the second and third sections 

 of the oesophagus (3'0 sec.). The sum of these differences 

 represents 6 sec., which indicates the time necessary for the 

 bolus to descend from the mouth to the extremity of the 

 oesophagus, and to overcome the resistance of the cardia and 

 enter the stomach. 



Meltzer confirmed his theory by the simpler method of 

 auscultation. On listening with the stethoscope in the region of 

 the stomach, or laterally, at the xiphoid process, a murmur is 

 almost always heard during the act of deglutition. This coincides 

 with the moment at which the bolus (or fluid mass) overcomes 

 the sphincter closure of the cardia and penetrates into the 

 stomach, which takes place 6-7 sec. after the commencement of 

 deglutition, and it is therefore called the terminal murmur. In 

 a much smaller number of cases there is, on the contrary, at the 

 initial moment of swallowing, a sharp whistling murmur, as if 

 the liquid swallowed had been shot forcibly and directly into the 

 stomach. When this sound, which may be called the initial 

 murmur, is very distinct, the terminal murmur is not heard; 

 when, on the contrary, it is very dull, the terminal murmur is 

 clearly heard as well, though faintly. In a small number of 

 cases no murmur is perceptible on auscultation during the 

 deglutition of liquids. 



Meltzer noted that many persons in whom the initial murmur 



