172 THE PROTEIN SUBSTANCES. 



reniformis, and others may also be classed with the hyalogens. As the various 

 bodies designated by KRUNKENBERG as hyalogens are very dissimilar, it is not 

 of much advantage to arrange these in special groups. 



2. Chondroproteins. 



Chondroproteins are those glycoproteins which as primary cleav- 

 age products yield protein and an ethereal sulphuric acid, the chondroitin- 

 sulphuric add. Chondromucoid, occurring in cartilage, is the best example 

 of this group. Amyloid occurring under pathological conditions also 

 belongs to this group. On account of the property of chondroitin-sul- 

 phuric acid of precipitating protein, it is also possible that under certain 

 circumstances combinations of this acid with protein may be precipitated 

 from the urine and be considered as Chondroproteins. 



The chondromucoid, the so-called tendon-mucin, and the osseomucoid 

 have greatest interest as constituents of cartilage, of the connective 

 tissues, and the bones, and on this account these bodies and their cleavage 

 product, chondroitin-sulphuric acid, will be treated in a following chap- 

 ter (IX). On the contrary, amyloid, which has always been considered 

 in connection with the protein substances, will be described here. 



Amyloid, so called by, VIRCHOW, is a protein substance appear- 

 ing under pathological conditions in the internal organs, such as the spleen, 

 liver and kidneys, as infiltrations; and in serous membranes as granules 

 with concentric layers. It probably also occurs as a constituent of 

 certain prostate calculi. The chondroprotein occurring under physio- 

 logical conditions in the walls of the arteries is, perhaps, according to 

 KRAWKOW, very closely related to the amyloid substance, but not iden- 

 tical with it, as shown by NEUBERG. 1 



Recently O. HANSSEN has studied the mechanically isolated amy- 

 loid obtained from the so-called " sago kernels " of an amyloid spleen, 

 and could not detect any conjugated sulphuric acid in it. According to 

 his investigations true amyloid is not a chondroprotein. MAYEDA 2 

 has also prepared an amyloid substance free from chondroitin-sulphuric 

 acid. On the other hand, HANSSEN has found that amyloid organs 

 (liver and spleen) are much richer in sulphuric acid that splits off than 

 normal organs, and it is not improbable that the amyloid formation goes 

 hand in hand with the formation of a chondroprotein. 



The amyloid prepared by KRAWKOW and NEUBERG had about the 

 same composition: C 49.0-50.1; H 7-7.2; N 14-14.1, and S 1.8-2.8 



1 Krawkow, Arch. f. exp. Path. u. Pharm., 40, which contains the literature; Neu- 

 berg, Verhandl. d. d. Pathol. Gesellsch., 1904. 



2 Hanssen, Bioch. Zeitschr., 13; Mayeda, Zeitschr. f. physiol. Chem., 58. 



