AMYJJJJD 



419 



composition in the normal aorta. Neuberg has studied especially tlie 

 protein constituent of the amyloid compound, and found it character- 

 ized by a high proportion of diamino-nitrogen,"^ as compared with 

 most proteins, as shown in the following table giving the percentage 

 of the total X contained in each of the three forms, amid-nitrogen 

 (ammonia), monamino-acids, and diamino-acids: 



Table I 



Liver amyloid 

 Spleen amyloid 

 Aorta "amyloid" 

 Gelatin 

 Casein 



The variations in the composition of the different amyloids, as shown 

 in the above table, indicate that the protein group may vary in dif- 

 ferent organs in different cases, and also indicate that the "amyloid- 

 like" substance of normal vessels is not the same as the pathological 

 substance. Corresponding variations were found in the apportion- 

 ment of the sulphur between that which is in the form of oxidized sul- 

 phur and the unoxidized sulphur. The proportion of the different 

 amino-aeids in the protein constituent of amyloid is strikingly like that 

 of thymus histon, and entirely dissimilar to the apparently closely 

 related elastin, as shown by Table II, 



This carries out the resemblance of amyloid to nucleoproteins, and, 

 likewise, Neuberg found amyloid very slowly digested by pepsin, and 

 much better by trv-psin, although less rapidly than simple protein; it 

 is also destroyed by autolytic enzymes, for amyloid tissues readily 



91 Corroborated by Jackson and Pearce (Jotir. Exp. Med., 1907 (9). 520), but 

 not by Mayeda ( Zeit. physiol. Chem., 1909 (58), 469), who found histidine, which 

 Neuberg had missed, and a lower arginine and lysine content than histon re- 

 quires. 



