40 PHYSIOLOGICAL CHEMISTRY. 



obtained pure, therefore its composition cannot be given with cer- 

 tainty. FKIEDREICH and KEKULE found C 53.6; H 7.0; N 15.0; 

 and S + 24.4$. KUHNE and RUDNEFF found 1.3$ sulphur. 

 Amyloid is not related to the carbohydrates, and on boiling with 

 acids it gives neither glucose nor any other reducing substance. 

 On the contrary, *it yields leucin and tyrosin. 



It is insoluble in water, alcohol, ether, dilute hydrochloric acid, 

 and acetic acid. It is dissolved in concentrated hydrochloric acid 

 or caustic alkali, and is converted into acid or alkali albuminates 

 according to the agents employed. According to KOSTJUKIN, 

 amyloid is dissolved by the gastric juice, which is the reverse of older 

 theories. Amyloid gives the xanthoproteic , acid reaction and the 

 reactions of MILLON and ADAMKIEWICZ. Its most important 

 property is its behavior with certain coloring matters. It is colored 

 reddish brown or a dingy violet by iodine; a violet or blue by iodine 

 and sulphuric acid ; red by methylaniline iodide, especially on the 

 addition of acetic acid ; and red by aniline green. 



Amyloid is prepared by extracting the tissue with cold and 

 then boiling water, afterwards with alcohol and ether. After boil- 

 ing with alcohol containing hydrochloric acid and digesting with 

 gastric juice, that which is insoluble is considered as amyloid. As 

 the amyloid may be dissolved by the gastric juice, the utility of this 

 method seems doubtful. 



