MOVEMENTS OF THE STOMACH. 133 



to a peculiar peristaltic movement, which has for its object to produce the 

 thorough intermixture of the gastric fluid with the alimentary mass, and so 

 to separate the portion which has been sufficiently reduced from the remain- 

 der. The fasciculi composing the muscular wall of the Human stomach 

 have recently been shown by Dr. J. B. Pettigrew 1 to be so disposed as to 

 form long spirals or figure-of-eight loops, of which the most external and 

 most internal fibres are nearly longitudinal, whilst those most centrally situ- 

 ated are nearly circular. The contraction of these fibres lessens the diam- 

 eter of the stomach in every direction ; and whilst the cavity is empty they 

 are uniformly contracted, so as to reduce the organ to its smallest dimen- 

 sions. When food is introduced, the contraction of the parietes as a whole 

 still continues, to such a degree as to make them closely apply themselves 

 to its surface ; but the contraction of the individual fasciculi alternates with 

 relaxation, in such a manner as to induce a great variety of motions in this 

 organ, sometimes transversely, and at other times longitudinally. " These 

 motions." remarks Dr. Beaumont, who has enjoyed a peculiar opportunity 

 of observing them,' 2 " not only produce a constant disturbance or churning 

 of the contents of the stomach, but they compel them at the same time to 

 revolve about the interior from point to point and from one extremity to the 

 other." In addition to these movements, there is a constant agitation of the 

 stomach produced by the respiratory muscles. The nature of these, and 

 indeed of all peristaltic movements, has been stated by Dr. Brinton 3 to resem- 

 ble very closely those produced by the descent of a perforated piston in a 

 closed tube containing fluid, for here there would be peripheral currents 

 passing in the same direction as the piston, and a central current flowing in 

 the opposite direction, through the perforation in the piston. The direction 

 which the particles of food take, as described by Dr. Beaumont, corresponds 

 very fairly with this view. He says: "The bolus as it enters the cardia 

 turns to the left, passes the aperture, descends into the splenic extremity, 

 and follows the great curvature towards the pyloric end. It then returns, 

 in the course of the smaller curvature (or as Dr. Briuton supposes, through 

 the axis of the stomach), and makes its appearance again at the aperture in 

 its descent into the great curvature, to perform similar revolutions. These 

 revolutions are completed in from one to three minutes. They are probably 

 induced, in a great measure, by the circular or transverse muscles of the 

 stomach. They are slower at first than after chymificatiou has considerably 

 advanced ;" at which time also there is an increased impulse towards the 

 pylorus. It is probable that, from the very commencement of chymitication 

 until the organ becomes empty, portions of chyme are continually passing 

 into the duodenum ; for the bulk of the alimentary mass progressively di- 

 minishes, and this the more rapidly as the process is nearer its completion. 

 The accelerated expulsion appears to be effected by a peculiar action of the 

 transverse muscles; and especially of that portion of them which surrounds 

 the stomach at about four inches from its pyloric extremity. This band is 

 so forcibly contracted at the latter part of the digestive process, that it almost 



1 Proceed, of the Koy. Soe., Lond., Juno 20th, 1867. 



2 See ihe Case of Alexis .St. Martin, witli Observations and Experiments by Dr. 

 Beaumont, republished in this country by Dr. Andrew Combe. This patient had a 

 large fictitious orifice in his stomach, remaining after a wound which had laid open 

 the cavity ; but his general health had been completely restored. 



3 Cyclop. Anat. and Phys., vol. v, pp. 313 and 345. See also, supporting Dr. 

 Brinton 's views, the observations of Dr. v. Braam Houckgeest (Pfliiger's Arcliiv, 

 1872, Band vi, p. 300). In these experiments the belly of the animal was opened 

 whilst the animal was immersed in a solution containing T 6 gths per cent, of common 

 salt in water, at blood heat. 



