THE ORIGIN OF AMYLOID 421 



observations on the difference in composition of amyloid of different 

 origins. 



Krawkow studied these reactions witli pure, isolated amyloid, and 

 found evidence that the iodin reaction depends upon the physical 

 properties of the amyloid, while tlie methyl-violet stain is a chemical 

 reaction, and hence the iodin reaction is much the more readily altered 

 or lost. As Dickinson ''^ says, amyloid stains with iodin simply as 

 if it absorbed the iodin more than does the surrounding tissue. The 

 methyl-violet reaction is due to the dye forming a compound with the 

 ehondn)itin-sali)huric acid, for Krawkow found that these substances 

 unite witli one another to form a rose-red precipitate. Hanssen, how- 

 ever, holds tliat the dyes react with the protein, the iodin with some 

 other, unknown labile substance. Schmidt found that implanted 

 pieces of amyloid lost their iodin reaction as they underwent auto- 

 lysis, while the methyl-violet reaction was still very distinct.'*'^ It 

 is evident, therefore, that iodin is not by itself a specific stain for 

 amyloid, especially as glycogen gives a similar reaction,''" while true 

 amyloid may not react. 



THE ORIGIN OF AMYLOID 



This question has not been at all cleared up as j^et by the advances 

 made in our knowledge of the chemistry of amyloid substance. The 

 fact that chondroitin-sulphuric acid is a characteristic constituent 

 suggests that this body may be liberated in considerable amount dur- 

 ing the destructive processes to which amyloidosis is usually sec- 

 ondary: this idea is further supported by the fact that amyloidosis 

 occurs particularly after chronic suppuration in bone and lungs, both 

 of which tissues, according to Krawkow, contain chondroitin-sulphuric 

 acid. This idea was not substantiated, however, by the experiments 

 made by Oddi and by Kettner,^^ who fed and injected into animals 

 large quantities of the sodium salt of chondroitin-sulphuric acid with- 

 out producing amyloid changes. Unpublished experiments of the 

 writer wdth the same material, as well as with ground-up cartilage and 

 with mucin, were equally unsuccessful. Likewise mice injected by 

 Strada "" with the nucleoprotein of pus, the so-called pyin, or with 

 chrondroitin-sulphuric acid, did not develop amyloidosis. Oestreich ^ 

 injected cancer patients with chondroitin-sulphuric acid for thera- 

 peutic purposes, but no amyloidosis resulted. As it is possible to 



95 Allbutt's System, vol. 3, p. 22.^. 



96Litten (Verb. Dent. Path. Gesell.. 1904 (7), 47) states that thionin and 

 kresyl-violet are the most specific stains for amyloid, which they color blue; 

 whereas methyl-violet stains red not only amyloid but also mucin, mast cell 

 granules, and tlie groinul substance of cartilage. V. Gieson's stain usually colors 

 amvloid pale vellow, and hvalin red. 



97 See Wichmann, Ziegler's Reitr., 1803 (13), 487. 



98 Arch. exp. Path. u. Pharm., 1902 (47), 178. 

 99Biochem. Zeit., 1909 (16), 195. 



1 Zeit. Krebsforsch.. 1911 (11), 44. 



