153 



XIX. " On the Immediate Principles of the Excrements of Man 

 and Animals in the Healthy Condition/' By WILLIAM 

 MARCET, M.D. Communicated by F. MARCET, F.R.S. 

 Received June 14, 1854. 



The author describes a new method of extracting the immediate 

 chemical constituents of the excrements of Man and animals, and 

 gives an account of the substances obtained by its employment. 



Healthy human faeces are boiled to exhaustion in alcohol. The 

 residue is insoluble in ether, and yields to boiling water nothing but 

 ammoniaco-magnesian phosphate. The strained alcoholic solution 

 deposits, on standing, a sediment, from which it is decanted and then 

 mixed with milk of lime. The subsiding lime is of a yellow-brown 

 colour ; it is dried on filtering-paper and treated with ether, cold or 

 hot, and the solution thus obtained yields, on spontaneous evapora- 

 tion, beautiful silky crystals, which are purified by solution in a 

 mixture of alcohol and ether, repeated filtration through animal 

 charcoal and recrystallization ; they then appear in circular groups, 

 have the form of acicular four-sided prisms, and polarize light very 

 readily. This crystalline body the author proposes to call Excretine. 

 It is very ^soluble in ether, cold or hot, but sparingly soluble in cold 

 alcohol; its solution has a decided though weak alkaline reaction. 

 It is insoluble in hot or cold water, and is not decomposed by dilute 

 mineral acids. It fuses between 95 and 96 C., and at a higher 

 temperature burns away without inorganic residue. When boiled 

 with solution of potash it does not dissolve. As to its qualitative 

 constitution, it is found to contain nitrogen and sulphur, though in 

 small proportions ; the products of its decomposition have not yet 

 been investigated. 



The author has in several cases observed the excretine to crystal- 

 lize directly in the alcoholic solution of fasces before the addition of 

 lime, and has scarcely any doubt that it exists for the most part in 

 a free state in the excrements, and constitutes one of their imme- 

 diate principles. As to its source, he observes that it appeared in 

 excess when a considerable quantity of beef had been taken, and in 

 less than the usual quantity in a case of diarrhoea attended with 

 loss of appetite ; but none could be directly obtained from beef on 



