80 PATHOLOGY OF ACUTE ATROPHY. 



PHYSIOLOGICALLY. Tyrosine may be obtained from 

 almost all the organs in which Leucine is to be found. 

 It can scarcely, however, be said to be a normal con- 

 stituent of the human frame, but rather appears to be 

 one of the artificial products of the decomposition of 

 highly nitrogenized matters. It also proves that it can 

 be artificially obtained in large quantities by acting 

 upon horn, hair, or feathers with sulphuric acid. 



PATHOLOGICALLY. These remarkable and peculiar pro- 

 perties of the urine indicate the existence of grave and 

 deeply important, although long unrecognized, abnormal 

 conditions of the metamorphosis of matter; and they fur- 

 nish no small insight into the transformations which take 

 place in the albuminous principles, in cases where the 

 functions of the liver are arrested. They likewise; 

 furnish prominent landmarks to the anxious physician, 

 which enables him to give due warning that the appear- 

 ance of Leucine and Tyrosine in the urine of his patients 

 is an almost certain sign of a rapidly approaching fatal 

 termination. As a pathological product, Tyrosine is 

 occasionally met with in the kidneys, in the urine, and 

 in the liver in a free state. In acute yellow atrophy, it 

 may be almost said to be constantly present in all 

 of these situations, as 1'ivrirlis Xeukomm, Scherer, 

 Staedeler, Harlry, ami others, have met in all cases 

 brought under their notice, well-formed crystals of tyro- 

 sine in the tissues of the atrophied liver, kidneys, and in 

 the urine, without subjecting the one or the other to 

 any chemical manipulation, but merely placing the 

 morbid product under the field of the microscope. 



Tyrosine has also been detected in the urine of those 

 suffering from severe small-pox, from typhus compli- 



