AMYLOID. 173 



per cent. The aorta amyloid of man and of the horse contained respect- 

 ively C 49.6 and 50.5; H 7.2; N 14.4 and 13.8; S 2.3 and 2.5 per cent. 

 As we cannot tell whether the amyloid analyzed was pure or not the 

 results are of questionable value. 



According to older investigations amyloid splits, by the action of 

 alkali, into protein and chondroi tin-sulphuric acid (see Chapter IX), 

 and according to KRAWKOW it is therefore a firm, perhaps ester-like 

 combination of this acid with protein. The protein, from the investiga- 

 tions of NEUBERG, is of a basic nature and most comparable to the 

 histones. The investigations of MAYEDA do not coincide with this view 

 as the amyloid protein obtained by him did not behave like a histone. 

 Its content of hexone bases was not greater than that of the proteins 

 of the normal organs and this amyloid protein did not yield any his- 

 tone-peptone. To all appearances, different investigators have worked 

 with different substances and it is possible that in the amyloid degenerated 

 organs partly chondroproteins and partly amyloid proteins may occur, 

 both of which give the color reactions. 



Amyloid is an amorphous white substance, insoluble in water, alcohol, 

 ether, dilute hydrochloric and acetic acids. It is soluble in concen- 

 trated hydrochloric acid or caustic alkali with decomposition. On boil- 

 ing with dilute hydrochloric acid it yields sulphuric acid and a reducing 

 substance. It is not dissolved by gastric juice, according to KRAWKOW, 

 which agrees with most of the older reports. It is nevertheless changed 

 so that it is soluble in dilute ammonia, while the typical amyloid is 

 insoluble therein. NEUBERG finds on the contrary that amyloid (from 

 liver) is digested by pepsin as well as by trypsin, although more slowly 

 than fibrin, and that it is also destroyed in autolysis, so that in life an 

 absorption is possible. The amyloid from the " sago " spleen studied 

 by HANSSEN showed the same behavior with gastric juice as KRAWKOW 

 found, while trypsin, as well as autolysis for months, was without action. 

 MAYEDA'S amyloid was gradually dissolved by gastric juice. 



Amyloid gives the xanthoproteic reaction and the reactions of MIL- 

 LON and ADAMKIEWICZ-HOPKINS. 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 also by aniline green. Of these color reactions those with 

 aniline dyes are the most important. The iodine reaction appears less 

 constant and is greatly dependent upon the physical condition of the 

 amyloid. The color reactions are due to the presence of the chondroitin- 

 sulphuric acid component, but this stands in opposition to the behavior 

 of the intact amyloid obtained by HANSSEN from the " sago " spleen 

 and the amyloprotein of MAYEDA. 



