PHYSIOLOGY OF DIGESTION. 553 



more aliment than those in less active employment. It consists of from 

 31 to 35 J ounces of dry nutritious matter daily; of which 26 ounces 

 are vegetable and the rest animal, 9J- ounces of salt meat, or 4^ ounces 

 of fresh, being the proportion of the latter. This is found to be an 

 ample allowance. In prisons a reduction must be made. In a convict 

 ship, which took out 433 prisoners to New Holland, in 1802, the mor- 

 tality was trifling, and the general health good, although the prisoners 

 were allowed only 16 ounces of vegetable food, and 7J ounces of animal 

 food per day. Whenever the allowance is more restricted, or a due ad- 

 mixture of animal and vegetable food is not permitted, the health suffers, 

 and signs of scorbutus appear; a result occasionally witnessed in our 

 public eleemosynary institutions, when under the care of ignorant and 

 too economical superintendents. It would seem, from the experiments 

 of M. Chossat, 1 that under such circumstances an incapability is induced 

 of digesting even the inadequate amount supplied. 



The smallest quantity of food upon which life is known to have been 

 actively supported was in the case of Cornaro, who affirms that he took 

 no more than 12 ounces a day, and that chiefly vegetable, for a period 

 of sixty-eight years. Of the amount that can be eaten by the glutton, 

 we have surprising instances on record, the stomach acquiring, at 

 times, an enormous capacity. Captain Parry relates the case of a young 

 Esquimaux, who was permitted to devour as much as he chose. It 

 amounted, in the twenty-four hours, to thirty-five pounds of various 

 kinds of aliment, including tallow candles; and a case has been pub- 

 lished of a Hindoo, who could eat a whole sheep at a time. 



These few remarks on the food of man will serve as an introduction 

 to the mode in which the various digestive processes are accomplished. 

 The more intimate consideration of alimentary substances, with their 

 comparative digestibility, &c., will be found in another work of the 

 author, to which the reader is referred. 2 



3. PHYSIOLOGY OP DIGESTION. 



The detail entered into regarding the various organs concerned in 

 digestion will have led to the anticipation, that the history of the func- 

 tion must be multiple and complex. The food is not, in the case of the 

 animal as it is in that of the vegetable placed in immediate contact 

 with the being to be nourished; an act of volition is, consequently, neces- 

 sary to procure and to convey it to the upper orifice of the digestive 

 tube. This act of volition is excited by an internal sensation that of 

 hunger which indicates the necessity for taking fresh nourishment into 

 the system. The appetite and hunger, with the prehension or reception 

 of food, must therefore be regarded part of the digestive operations. 

 These may be enumerated and investigated in the following order: 

 1st. Hunger, or the sensation that excites us to take food. 2dly. Pre- 

 hension 'of food, the voluntary muscular action, that introduces it into 

 the mouth. 3dly. Oral or buccal digestion, comprising the changes 



1 Referred to. at page 558. 



2 Human Health, p. 179, Philad., 1844. For different dietaries, &c., see Pereira, Treatise 

 on Food and Diet, Amer. edit., by Dr. C. A. Lee, p. 222, New York, 1843; and Art. Diet 

 Scale, in the author's Med. Dictionary, 7th edit., Philad., 1848. 



