370 THE EXCRETIONS: 



100 parts of the dried fsecal mass contained : 



Analysis 150. 



Fat ... 52-00 



Bile-pigment with fat . . 16-00 



Coagulated casein with mucus . 18 '00 



Moisture and loss . .14-00 



No accurate analysis of the excrements of the healthy adult 

 has been made, that I am aware of, since 1804, when Berzelius 

 investigated the subject : I shall therefore give his results. The 

 excrements mix very gradually with water, which they render 

 mucous and turbid, and which is a long time clearing itself : 

 on decanting the mixture, there remains a grayish-brown re- 

 sidue consisting of insoluble vegetable matter, through which 

 a thick grayish-green fluid permeates, depositing a copious 

 sediment when placed in a corked bottle. 



The thinner supernatant portion can only be filtered with 

 difficulty. If the fluid is very concentrated, and is at the same 

 time clear, it will soon be observed to become dark, a change 

 of colour apparently due to the action of the atmosphere. 

 When this fluid is evaporated, crystals of ammoniaco-magne- 

 sian phosphate gradually form on the surface; as they were not 

 previously apparent we may conclude that the ammonia is sub- 

 sequently produced. On extracting with alcohol the residue left 

 after the evaporation of the water, a substance of a reddish- 

 brown colour is taken up, while a grayish-brown matter (A) 

 remains undissolved. 



The alcoholic solution yields on evaporation a residue which 

 forms a resinous precipitate with sulphuric acid, consisting of 

 bilifellinic acid with an excess of bilin, which may be separated 

 by oxide of lead into bilifellinate of lead and bilin. 



On distilling the mixture with sulphuric acid we obtain a 

 fluid which yields traces of hydrochloric but not of acetic acid: 

 on saturating the sulphuric acid in the residue with baryta, 

 after the separation of the biliary resin, and then evaporating, 

 and treating the dry mass with alcohol, an extractive matter of 

 a reddish-brown tint is taken up, which is apparently the cause 

 of the change of colour to which we have already alluded in 

 the concentrated aqueous solution of the feeces. This sub- 

 stance is soluble in alcohol and in water, is almost entirely 

 precipitated by the salts of tin, lead, and silver, and on the addi- 



