502 



OF FOOD, AND THE DIGESTIVE PROCESS. 



often much greater than that which has been ingested, and must be derived 

 from the blood. The secretion of the ccecum has been ascertained to be, in 

 herbivorous animals, distinctly acid during digestion ; and there is reason to 

 believe, that the food there undergoes a second process, analogous to that to 

 which it has been submitted in the stomach, and fitted to extract from it what- 

 ever undissolved alimentary matter it may still contain. There is no evi- 

 dence, however, that this is the case in Man, whose ccecum (commonly termed 

 the appendix coeci vermiformis) is very small, compared to that of most her- 

 bivorous animals. 



662. The act of Defecation having been already sufficiently considered 

 ( 391), it only remains to notice the composition of the Faeces. These are 

 made up of certain parts of the food, which have not been reduced and ab- 

 sorbed ; together with that portion of the secretions poured into the aliment- 

 ary canal between the mouth and the anus, which has not been taken back 

 again into the system. Of the former portion, the constituents may be in 

 great part determined by the Microscope. Thus the cell-walls of the Vegeta- 

 ble tissues whose contents have been extracted, the entire woody fibres (on 

 which the digestive process has no influence), the granules of starch, when 

 they have undergone no preparation before being swallowed, portions of 

 tendon, ligament, adipose tissue, and even of muscular fibre, with other 

 substances constituting the undigested residue of the food, may be readily 

 detected. Besides these, the microscope enables us to recognize the brown 

 colouring-matter of the bile, epithelium-cells and mucus-corpuscles, and various 

 saline particles, especially those of the ammoniaco-magnesian phosphate, whose 

 crystals are well-defined ; most of which are derived from the secretions. 

 The following is the result of the proximate analysis of the faeces of an in- 

 dividual in good health, who had taken the ordinary diet of this country, as 

 given by Dr. Percy : 



Substances soluble in ether (brownish yellow fat) 



alcohol of -830 



water (brown resinoid matter) 

 Organic matter insoluble in the above menstrua . 

 Salts soluble in water .... 

 Salts insoluble in water . . . 



11-05 

 10-74 

 11-01' 

 49-33 

 4-70 

 11-61 



Ultimate analysis of the same faeces gave the following as the proportion of 

 the components of the Organic constituents ; Carbon 46'20, Hydrogen 6'72, 

 Nitrogen and Oxygen 30'71. The mineral ash of faecal matter has been ex- 

 amined by Enderlin ; who has given the following as the proportion of its 

 ingredients : 



Chloride of sodium and alkaline sulphates 



Bibasic phosphate of soda 



Phosphates of lime and magnesia 



Phosphate of iron . 



Sulphate of lime . 



Silica 



Soluble in water. 



1-367? 



2-033 5 

 80-372 ~\ 



~ ' > Insoluble in water. 



4'OoU I 



7-940 J 



It further appears from the inquiries of Enderlin, that a portion of the or- 

 ganic matter taken up by alcohol, sometimes (but not constantly) consists of 

 Choleate of soda, the characteristic ingredient of bile ; and he thinks that this 

 is more likely to be present, when the faeces have remained for only a short 

 period in the large intestine, and when ihere has been less time for its re- 

 absorption. In the faecal discharges which result from the action of mercu- 

 rials, large quantities of biliary matter may be detected, very little changed. 



