OF THE AMYLOID DEGENERATION, 137 



nei'ation,^' similar to that which takes place in the arteries. 

 Crystalline cholesterin existed only on the surface, beneath 

 which, however, the matrix presented numerous alterations ; 

 isolated portions were composed, in great part, of the un- 

 changed, hyaline, dense substance, close to which might be 

 noticed considerable tracts and masses in which the matrix 

 was stx'eaky and fibrous. The fibres in some parts resembled 

 the rigid filaments in the WL^ll-known asbestos-like portions of 

 the costal cartilages, and in others assumed more the aspect of 

 hard, wavy, and strongly refractive strife. On the addition of 

 solutions of iodine, either the simply aqueous, or made with 

 iodide of potassium, some portions of the microscopic section 

 at once assumed an intense reddish-yellow (iodine-red) colour, 

 Avhilst others remained perfectly clear and colourless ; the 

 greater part presented a yellowish, and, on more prolonged 

 action of the reagent, a yellowish-brown hue. If sulphuric 

 acid or chloride of zinc be now added, the reddish-yellow 

 spots are immediately rendered of a violet, or occasionally, 

 bright blue colour, although a strong reddish tinge is always 

 retained. Under the action of a very concentrated solution of 

 iodine, also, the colour becomes at once dark red, or nearly 

 violet-red, especially when the section so treated is dried and 

 again moistened with water. The places in the section where 

 the iodine reaction took place might be very distinctly recog- 

 nized, even by the naked eye, as dark, reddish, or blackish-red 

 points, particularly when thin sections were viewed over a 

 clean, white surface. When examined with the microscope it 

 was readily seen that it was not cholesterin in any form which 

 aflforded the simple reaction with iodine ; as is usual, this 

 substance, even after the addition of iodine, remained colour- 

 less, and did not exhibit any of the often-noticed changes of 

 colour, except under the energetic action of sulphuric acid or 

 of chloride of zinc. 



It was now a point of much interest to determine in which 

 of the structural elements the reaction took place ; with respect 

 to which it was at once evident that both the matrix-substance 

 and the corpuscles participated in it, either each singly, or 

 both, though less extensively, conjointly. Of the corpuscles, 

 again, it Avas quite evident that it was the thick capsules which 

 afforded the deepest colouring, which was intense in proportion 

 as the corpuscles were of larger size, and more free in the 

 surrounding matrix ; but in some places the true cell (contents 

 of the capsules) also appeared to be similarly affected ; and, 

 especially in the smaller ones, Virchow often noticed the entire 

 corpuscles coloured red or violet throughout. 



It was remarkable that no microscopic characters could be 



