ADDITIONS AND NOTES TO VOL. II. 519 



the feeces ; but Wehsarg never observed crystals of choles- 

 terin*: connective tissue was only noticed after a very abundant 

 flesh-diet. 



The ether-extract of the faeces varied extremely with the nature 

 of the food. After a very fatty diet it rose to 31*2 grammes, or 

 58'2 of the dried mass; the mean was 11*5, and the minimum 

 8'5-g-. It consists for the most part of a waxy fat. 



The alcohol-extract was found to amount (as the mean of 3 

 observations) to 15'6-j}-, and it may rise to double this quantity in 

 diarrhoea. After drying this extract (which when cold forms a 

 dark brownish-red mass) in the air-bath Wehsarg could only once 

 detect the presence of bile in it with certainty, although he often 

 got doubtful indications ; and on the addition of nitric acid to 

 fresh feeces there was only twice an undoubted manifestation of 

 the evidence of bile-pigment. Hence his observations confirm the 

 view., that as a general rule no bile occurs in an unchanged state in 

 the faeces. 



The water-extract is a brownish-black mass, which always 

 undergoes decomposition on drying. Its average quantity is about 

 20 of the dry feeces. 



The quantity of salts contained in the faeces, as compared with 

 that in the urine, is very small. Mere traces of sulphuric acid and 

 chlorine, and often not even a trace, are to be found, unless when 

 large quantities of these substances have been introduced into the 

 system. Chlorine, is, however, more frequently found than sul- 

 phuric acid. 



The salts which are precipitable by ammonia vary in different 

 individuals. The mean of 7 observations was 4* !(), the maximum 

 being 6'90, and the minimum 1*73. After a dose of sulphate of 

 magnesia, this number may rise to 20'50J. The great mass of 

 these salts is phosphate of magnesia, and associated with it is a 

 small quantity of phosphate of lime with a little iron. 



It appears, from Marcet's experiments, that healthy human 

 excrements contain : 



1. A new organic substance, possessing an alkaline reaction, 

 which its discoverer names excretine. In its pure state it appears 

 in circular groups of crystals, which have the form of acicular 

 four-sided prisms, and polarise light very readily. It is very 

 soluble in ether, cold or hot, but sparingly soluble in cold alcohol ; 

 it is insoluble in water, and is not decomposed by dilute mineral 

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

 perature burns away without inorganic residue. It does not 



