PATHOLOGY OF ACUTE ATROPHY. 81 



cated with jaundice, and from chronic atrophy of the 

 liver, supervening on obstructed gall-duct. The pecu- 

 liarity of the urine of most value in a clinical point of 

 view is the deposit, upon exposure to the cold, of a 

 greenish yellow precipitate, which, even with the naked 

 eye, and still more readily upon microscopical examina- 

 tion, can be recognized as differing from all other 

 deposits. 



This has been amply confirmed by the observations 

 and researches of Frerichs, Murchison, Harley, and 

 others. Harley, in his excellent work on the " Urine 

 and its Derangements," puts the following leading and 

 practical question : " Where does the tyrosine met with 

 in disease come from ? " " The results," says that author, 

 " of my experiments on animals to which jaundice had 

 been artificially given led me to the belief that tyrosine 

 and leucine stand in the same relation to each other in 

 disease as the two bile-acids, glycocholic and tauro- 

 cholic, do in health. Glycocholic acid is crystallizable, 

 taurocholic is not. 



"The urine of some of the dogs to which I gave 

 artificial jaundice by the subcutaneous injection of bile, 

 contained both leucine and tyrosine, and even in one of 

 these cases crystals of tyrosine spontaneously formed in 

 the bile taken from the animal's gall-bladder immediately 

 after death, and merely allowed slowly to evaporate. In 

 another case, again, free crystals of tyrosine were 

 encountered in the tissue of the liver itself, all of which 

 facts led me to the conclusion that tyrosine and leucine 

 are the products either of the arrested or of the retro- 

 grade metamorphosis of glycocholic and taurocholic 

 acid." 



