its 



alvine evacuation takes place, and is facilitated by the secretion of the 

 mucous follicles of the rectum: these glands, squeezed by the pressure 

 of the faeces, pour out their contents, and lubricate the circumference 

 of its lower aperture. When the faeces have been voided, the dia- 

 phragm rises, the large muscles of the abdomen cease to press backwards 

 and downwards upon the viscera of that cavity; the perineum ascends 

 and the sphincters close, till a renewal of the same call, again brings on 

 the same action. 



The call to avoid the fseces, is more frequent in children than in adults, 

 because, at an early period of life, the sensibility of the intestinal canal 

 is greater, the contents of the bowels more fluid, and digestion more ac- 

 tive. As we advance in years, sensibility becoming impaired, and con- 

 tractility experiencing a proportionate loss of power ; the secretions be- 

 ing, likewise, less abundant, the bowels become sluggish, the stools more 

 scanty and indurated. They are, likewise, less frequent and copious in 

 women than in men, whether it be, that the digestive power extracts 

 from the aliment, a greater proportion of nutritious matter, or that the 

 menstrual evacuation being a kind of substitute for the intestinal secre- 

 tions, less remains to add to the bulk of the excrementitious mass. The 

 evacuation of the faeces may be brought on by throwing liquids into the 

 rectum, which dilute the faeces, detach them from the parietes of the in- 

 testines, and, exciting on these parietes an irritation to which they are 

 not accustomed, determine their contraction. 



The fetor of the excrements depends on their incipient putrefaction 

 in the great intestines. This decomposition is, almost always, attended 

 with the extrication of gases, in which sulphurated hydrogen prevails. 

 This gas, which at times escapes, and which at others impregnates the 

 faeces, is the cause of the black colour which they give to silver exposed 

 to their action. One may recognize in the excrements the colouring- 

 matter of vegetables, such as the green colour of spinage, the red of beet- 

 root; one may, likewise, find among them, the fibrous parts of plants and 

 animals, the indurated bark, and the seeds covered with their husks. 

 The digestive juices have so little action on husks, that seeds which 

 have not been broken down by the organs of mastication, frequently con- 

 tinue capable of vegetation. 



During the process of digestion, the food contained in the stomach and 

 intestines absorbs or extricates different gases. M. Jurine, of Geneva, 

 opened the body of a maniac who had been dead a few hours, and collect- 

 ed the gases which escaped; he observed, that the proportion of oxygen 

 and carbonic acid diminishes from the stomach towards the great intes- 

 tines, while on the contrary, there is, in these, an increased proportion of 

 azote ; that hydrogen is more abundant in the great than in the small in- 

 testines, that it is less in quantity in these than the stomach*. Do the 

 oxygen and azote form a part of the atmospherical air which is taken in 

 with the food and with the saliva, and which is disengaged by the heat 

 of the intestinal canal ? Or are these gases the result of the decomposi- 

 tion of the food and of the intestinal fluids? Besides, may not the gas 

 contained in the intestines of a dead body, have been formed at the 

 moment of death ? We know that in several instances, at the moment 

 contractility is forsaking our organs, the intestines become distended by 



* See APPENDIX, Note C. 



