DIE 



DIE 



Grant's history of the Mauritius, how- 

 ever, this bird is stated to be no longer 

 found in that island or Bourbon ; and 

 most probably is to be classed among 

 those species which bave been destroyed, 

 through the ease with which they were 

 taken : on uninhabited islands, however, 

 it is added, the hooded dodo may possi- 

 bly yet be found. The observation of 

 Mr. Grant, with respect to the dodo, 

 must be supposed to apply to all those of 

 the species, of which, indeed, the one 

 above-mentioned is given upon much 

 better authority than attaches to the other 

 two. Latham thinks it not improbable 

 that these two differed from the first 

 only in age or sex. Dr. Shaw, in the Na- 

 turalist's Miscellany, figures a foot of 

 the dodo found in the British Museum. 

 See Aves. Plate VI. fig. 2. 



DIDYNAMIA, in botany, the name of 

 the fourteenth class in Linnaeus's method, 

 consisting of plants with hermaphrodite 

 flowers, which have four stamina or male 

 organs, two of which are long, and 

 two short. 



DIETETICS, the science or philosophy 

 of diets : that which teaches us to adapt 

 particular foods to particular organs of 

 digestion, or to particular states of the 

 same organs ; so that the greatest pos- 

 sible portion of nutriment may be ex- 

 tracted from a given quantity of nutritive 

 matter ; or a sufficient portion may be 

 obtained with the least possible quantity 

 of organic action and exhaustion. In 

 this sense, the science of dietetics em- 

 braces a knowledge as well of the organs 

 and economy of digestion, as of the sub- 

 stances to be digested ; and under this 

 division we shall treat of it in the sketch 

 before us. 



The organs of digestion differ exceed- 

 ingly in different classes of animals ; but 

 in all, even in zoophytes and infusory 

 worms, there is one which answers the 

 purpose of a stomach, the most important 

 of all the digestive organs. In the more 

 perfjpct animals, the salivary glands, the 

 pancreas, and the liver, are all said to 

 concur with the stomach, and, perhaps, 

 the smaller intestines, in the process of 

 digestion; and, according to Cruikshank, 

 about a pint of gastric, or stomach secre- 

 tion half a pint of saliva, half a pint of 

 pancreatic juice, and twenty ounces of 

 bile, are poured into the human stomach 

 in the period of every twenty -four hours; 

 while the same process is aided by a 

 considerable quantity of solvent fluid, of 

 a different kind, secreted through the 

 whole length of the internal surfaces of 



the intestines. Yet as some doubts have 

 been entertained as to the relative con- 

 tributions of these different viscera ; and 

 as in different classes of animals they 

 vary in every possible mode of deficiency, 

 till at length, in the lowest orders, we find 

 nothing but the stomach itself left t 

 maintain the entire economy ; more espe- 

 cially as we cannot at present enter into 

 the question of the relative importance 

 of the rest ; we shall confine our observa- 

 tions almost exclusively to the stomach, 

 and shall only glance at the collatitious 

 viscera, as we may perceive it absolutely 

 necessary. 



If we look back into antiquity,' we 

 shall find that the earliest opinion on the 

 cause of digestion was that of putridity. 

 It was by this process that both Hippo- 

 crates and Empedocles supposed the food, 

 when taken into the stomach, to be re- 

 duced to a proper state for the support of 

 the animal system. Galen and his dis- 

 ciples conceived an idea that it was 

 brought about by heat. Van Helmont, 

 whose wild conjectures can only be ac- 

 counted for by the spirit and enthusiasm 

 of alchemy which raged in his time, at- 

 tributed digestion to the vital energy of 

 the soul, which resided, as he thought, 

 in the stomach. 



Grew and Santarelli were of opinion, 

 that the spirits which are poured forth 

 from the nerves of the stomach served 

 for the concoction of the food. Boer- 

 haave, who has in reality only attempted 

 to reconcile the variety of opinions that 

 had been proposed before him, supposes 

 there are two principal agents in this 

 vital function, viz. the different fluids that 

 are collected in the stomach, and the me- 

 chanical action of that organ ; the secon- 

 dary agents, according to him, are heat, 

 air, the nervous fluid, the remains of the 

 food, and an incipient fermentation, op- 

 posing it in the extensive sense in which 

 it was considered before him. With re- 

 spect to the gastric fluid, his ideas ap- 

 pear to be indeterminate and unsettled ; 

 he, however, conceived that its action on 

 the food was merely as a simple diluent, 

 like water, when heated to the same tem- 

 perature. He had no suspicion of its 

 being a solvent, or that it was capable of 

 acting upon the more tenacious and hard 

 substances that were taken in as food. 

 According to Pringle and Macbride, di- 

 gestion is carried on by a complete fer- 

 mentative process. The food, divided by 

 mastication, and penetrated by the saliva, 

 begins, as soon as it enters the stomach, 

 to be agitated by that intestine motion 



