THE ORIGIN OF AMYLOID 351 



THE ORIGIN OF AMYLOID 



This question has not been at all cleared up as yet by the 

 advances made in our knowledge of the chemistry of amyloid 

 substance. The fact that chondroitin-sulphuric acid is a char- 

 acteristic constituent suggests that this body may be liberated 

 in considerable amount during the destructive processes to 

 which amyloidosis is usually secondary ; 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, 1 who fed and injected into animals 

 large quantities of the sodium salt of chondroitin-sulphuric acid 

 without producing amyloid changes. Unpublished experiments 

 of the writer with the same material, as well as with ground- 

 up cartilage and with mucin, were equally unsuccessful. As it 

 is possible to cause amyloidosis experimentally in animals, 

 especially chickens and rabbits, by causing protracted suppura- 

 tion or chronic intoxication with bacterial filtrates, these nega- 

 tive results speak strongly against the idea of a transportation 

 of chondroitin-sulphuric acid, but do not determine it finally. 

 Especially important in this respect is the extreme difficulty of 

 producing amyloid experimentally, for in only a certain proportion 

 of cases are the experiments positive (in but about one-third of 

 Davidsohn's 2 100 trials ; and many other experimenters have been 

 much less successful 3 ). Davidsohn, failing always to get amyloid 

 experimentally after the spleen had been removed, suggests that 

 this organ (in which amyloid is usually earliest and most abun- 

 dantly observed) produces an enzyme, which causes a precipitation 

 of amyloid in the tissues from a soluble precursor brought in 

 the blood from the site of cell destruction. Schmidt 4 gives an 

 excellent discussion of the various features of amyloidosis, and 

 also considers it probable that some enzymatic action causes a 

 precipitation or coagulation of some substance in the tissue- 

 spaces or lymph- vessels. Amyloid is never deposited in the 

 cells themselves, and it seems to be now generally considered 

 that the amyloid material is infiltrated in the form of a soluble 

 modification or precursor, and that it is not manufactured in 

 the organ where it is found. It is an interesting fact that a 



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



2 Verb. Deut. Path. Gesell., 1904 (7), 39. 



3 See Tarchetti, Deut. Arch. klin. Med., 1903 (75), 526. 

 * Verb. Deut. Path. Gesell., 1904 (7), 2. 



