134 DIGESTION. 



anatomy of the digestive organs, particularly as regards the 

 length and capacity of the alimentary canal. In the carni- 

 vora, in which the food contains comparatively little in- 

 digestible residue, the intestine is but three or four times 

 the length of the body (i. e. from the mouth to the anus), and 

 the colon, which receives the residue of digestion, is of small 

 capacity ; while in the herbivora, in which the bulk of food, 

 compared with its nutritious principles, is enormous, there 

 are frequently four distinct cavities to the stomach, and the 

 intestine is ten, twelve, and in some (the sheep) twenty-eight 

 times the length of the body, with a colon of very large size. 

 The food of man is derived from both the animal and vege- 

 table kingdom, and in length and capacity, the alimentary 

 canal is between that of the carnivora and the herbivora, be- 

 ing from six to seven times the length of the body. 1 



A full meal probably occupies from two to four hours in 

 its digestion, this depending, of course, on the kind of food, 

 the fineness of its comminution by mastication, etc. 2 The 



1 CUVIER, Lemons d 1 Anatomic Comparee, Paris, 1835, tome iv., Deuxieme Par- 

 tie, p. 173. In this work is given a long and elaborate table of measurements of 

 the intestines as compared with the length of the trunk ; the measurements of the 

 intestines, including all between the pylorus and the anus, and the measurement 

 of the trunk, in the mammalia, extending from the mouth to the anus. Taking the 

 latter measurement in the human subject as from two and a quarter to two and 

 a half feet, the length of the intestinal canal would be, in general terms, from fif- 

 teen to eighteen feet. This is much less than the estimate generally given in works 

 on anatomy, in which the measurements given vary between twenty and thirty feet. 

 In the natural condition of the parts, the estimate of Cuvier is perhaps pretty near 

 the truth, for the intestines are very extensible, and are much longer when de- 

 tached from the mesentery and stretched out, than they are in situ ; but the 

 standard of measurement, i. e., the length of the body, is very indefinite. 



2 This estimate is roughly made from the celebrated experiments of Dr. Beau- 

 mont in the case of Alexis St. Martin (Experiments and Observations on the Gas- 

 tric Juice and the Physiology of Digestion, Plattsburg, 1833). In one of these ob- 

 servations, after a meal of roast- turkey, potatoes, and bread, the stomach was 

 found empty in two and a half hours (p. 171). The stomach was found empty 

 one hour and thirty-five minutes after a breakfast of venison-steak, cranberry- 

 jelly, and br^ad (p. 147). From a large number of observations, Dr. Beaumont 

 concludes " that the time required for the disposal of a moderate meal of the 

 fibrous parts of meat, with bread, etc., is from three to three and a half hours." 



