420 RETROGRESSIVE CHANGES 



undergo autolysis."- Neuberg considers, from the above results, that 

 amyloid is probably a transformation-product of the tissue protein, 

 similar to the transformation of simple proteins into protamins that 

 occurs in the testicle of spawning- salmon as they go up the streams, 

 as shown by Micscher's classical studies. Raubitschek "^ found that 

 isolated amyloid, when used for immune reactions, behaved like a 

 specific protein, different from the normal proteins of the animal from 

 whence it came and apparently biologically the same in different spe- 

 cies. (This observation awaits confirmation.) 



Krawkow considers that amyloid differs from normal chondroitin- 

 sulphuric acid compounds, such as cartilage, in that in the latter the 

 acid radical is in a loose combination with the protein, while in amy- 

 loid the combination is a very firm one, perhaps in the nature of an 

 ester. The occurrence of the typical amyloid reaction in what ap- 

 pears otherwise to be normal cartilage, occasionally observed in senile 

 tissues, may be due to the transformation of loosely bound into firmly 

 bound chondroitin-sulphuric acid. In any event, amyloid is not essen- 

 tially a pathological product, but rather a slightly modified nonnal 

 constituent of the body. However, in view of the contradictory results 

 of Hanssen and Mayeda, as yet uncontroverted, the chemical nature of 

 amyloid must be considered as undetennined. An important con- 

 sideration is that amyloid deposition occurs under similar conditions 

 in all sorts of animals, including birds ; it is very often found in 

 the livers of antitoxin horses, and mice are especially prone to a 

 severe amyloidosis after relatively slight and brief infectious pro- 

 cesses."* 



Staining Properties. — The classical reaction for amyloid is its 

 staining a reddish brown when treated with iodin (best as Lugol's so- 

 lution) in the fresh state. Such stained specimens, if afterward 

 treated with dilute sulphuric acid, usually become blue or greenish, but 

 may merely tuni a deeper brown. Occasionally old compact amyloid 

 may stain bluish or green with iodin alone. The iodin reaction dis- 

 appears in specimens that have been kept for some time in preserv- 

 ing fluids, or in tissues that have become alkaline, and is generally 

 less persistent than the metachromatic staining by methyl-violet or 

 methyl-green, which color the amyloid red. Occasionally an otherwise 

 typical amyloid will fail to react to iodin, but will stain well with 

 methyl-violet. All these variations may occui- in different specimens 

 from the same body, and the blue iodin-sul]ihuric acid reaction is 

 usually given well only by splenic amyloid. These variations proba- 

 bly depend upon the age and stage of development of the amyloid, or 

 upon secondaiy alterations, and are perhaps related to Neuberg's 



''2 f 'oncorniTiL,' llic ubsorption of aiinloid soe Dantcliokdw, Virclunv's Arcliiv., 

 1907 nS7), 1. 



osVorh. Dont. Path. Cosoll.. 1010 (14), 27.1 



niSoo Fin/.i, I^ Rporinifiit.. 1011 {C>r^). 4S.1 ; Davidsohn, VirchowV Arcli.. 1008 

 (192), 226. 



