91 



the food. There are found in it, besides, at certain times of the year, 

 two roundish concretions, on each side, under its internal membrane. 

 These concretions, improperly termed crabs' eyes, consist of carbonate 

 of lime joined to a small quantity of gelatinous animal matter; they dis- 

 appear, when, after the annual shedding of the shell, the external cover- 

 ing, at first membranous, becomes solid from the deposition of the calca- 

 reous matter of which they are formed. 



The very great difference between the stomach of these animals and 

 that of man, ought to have precluded every idea of comparing them toge- 

 ther. Spallanzani has justly observed, that in regard to the muscular 

 power of the parietes of the stomach, animals might be divided into three 

 classes, the most numerous of which consists of those creatures, whose 

 stomach is almost entirely membranous, and furnished with a muscular 

 coat of very little thickness. In thi class are contained, man, quadru- 

 peds, birds of prey, reptiles, and fishes. Notwithstanding the weakness 

 of that muscular coat, Pitcairn, by a misapplied calculation, has estimated 

 its power at 12,951 pounds; he reckons at 248,335 pounds, that of the 

 diaphragm and of the abdominal muscles which act on the stomach, and 

 compress it in the alternate motions of respiration. What does so exag- 

 gerated a calculation prove, except, as Garat observes, that this vain 

 show of axioms, definitions, scholia, and corollaries, with which works 

 not belonging to mathematics have been disfigured, have served only to 

 protect vague, confused, and false notions, under the cover of imposing 

 and respected forms. One need only introduce one's hand into the abdo- 

 men of a living animal, or a finger into a wound of the stomach, to as- 

 certain that the force of that viscus on its contents, does not exceed a 

 few ounces. 



XIX. The learned and indefatigable Haller thought, that the food was 

 merely softened and diluted by the gastric juice. This maceration was, 

 in his opinion, promoted and accelerated by the warmth of the part, by 

 the incipient putrefaction, by the gentle bui continual motions which the 

 alimentary substance undergoes. Maceration, in time, overcomes the 

 force of cohesion of the most solid substances ; but by dilution it never 

 changes their nature. Haller rested on the experiments of Albinus, 

 on the conversion of membranous tissues into mucilage, by protracted 

 maceration. 



In ruminating animals, the cavity of the stomach is divided into four 

 parts, which open into one another, and of which the three first commu- 

 nicate with the oesophagus. When the grass, after imperfect trituratiou 

 by the organs of mastication, whose power is inconsiderable, has reached 

 the paunch, which is the first and largest of the four stomachs, it under- 

 goes a real maceration, together with an incipient acid fermentation. 

 The contractions of the stomach propel the food, in small quantities at a 

 time, into the bonnet, which is smaller and more muscular than the 

 paunch; it coils on itself, covers with mucus the already softened food, 

 then forms it into a ball, which rises into the mouth, by a truly antiperi- 

 staltic motion of the oesophagus. The alimentary bolus, after having 

 been chewed over again by the animal, which seems to enjoy that pro- 

 cess, descends along the oesophagus into the third stomach, called the 

 manyplus, on account of the large and numerous folds of its inner mem- 

 brane. From this cavity the food enters into the abomasum, in which 

 the stomachic digestion is completed. Such is the mechanism of rumi- 

 nation, a function peculiar to animals that have four stomachs: they do 



