206 THE FECES. 



The individual constituents of the feces may be grouped as 

 follows : 



1. Food-material which has escaped the process of digestion, and 

 of bacterial decomposition, such as starches, muscle-tissue, connective- 

 tissue, fats, etc. 



2. Undigestible material, which has been ingested as such, or 

 which has resulted from the decomposition of complex substances 

 which are partly digestible, such as gums, pectins, resins, chitin, 

 chlorophyl, hsematin, and insoluble silicates, sulphates, phosphates, 

 etc. 



3. Derivatives of the bile, such as the dyslysins, cholesterin, and 

 exceptionally the native biliary acids as such, and further hydrobili- 

 rubin, stercobilin, etc. 



4. Intestinal mucus. 



5. Products of albuminous digestion, such as albumoses, peptone- 

 like bodies, leucin, ty rosin, asparaginic acid, and glutaminic acid. 



6. Products of bacterial action. These comprise the entire series 

 of fatty acids from acetic acid to palmitic acid ; further, lactic acid, 

 succinic acid, glutaric acid, leucin, tyrosin, hydroparacumaric acid, 

 para-oxy-phenyl-acetic acid, phenyl-propionic acid, phenyl-acetic 

 acid, phenol, paracresol, indol, skatol, skatol-carbonic acid, ammo- 

 nium carbonate, ammonium sulphide, etc. 



7. Products of metabolism, which are in part eliminated through 

 the intestines, such as uric acid, urea, xanthin bases, etc. 



8. Water. 



9. Gases, which are in part referable to the various fermentative 

 and putrefactive processes which take place in the intestinal canal, 

 such as carbon dioxide, methane, hydrogen, hydrogen sulphide, 

 methyl-mercaptan, and phosphin. The nitrogen, on the other hand, 

 which is also constantly met with, is probably derived from the 

 blood, and has in part been swallowed. 



Many of these substances have already been considered in detail, 

 and it will suffice at this place to indicate the manner in which the 

 most important products of albuminous putrefaction can be isolated 

 from the feces. 



ANALYSIS OF THE PRODUCTS OF ALBUMINOUS 

 PUTREFACTION. 



The feces are diluted with water, passed through a muslin filter 

 to remove particles of food-material, and distilled until about four- 

 fifths of the entire volume have passed over. The distillate B con- 

 tains indol, skatol, phenol, paracresol, and the volatile acids which 

 are present in the free state, while the remaining products of putre- 

 faction are found in the residual solution A. The distillate B is 

 neutralized with sodium carbonate and redistilled. This second dis- 

 tillate, C, contains indol, skatol, phenol, and paracresol, while the 

 volatile acids remain behind as sodium salts, and can be sepa- 



