ATSOPHY AND DEGENERATIONS OF TISSUE. 63 



investigation it lias been described — (I.) By Virchow under tlie 

 name of ' animal amyloid,' lie believing, from the behaviour of 

 the transformed substance with iodine and sulphuric acid, that 

 the substance must be classified with the vegetable carbo-hydrates 

 — cellulose and starch : (2.) Meckel retains the name of 

 * lardaceous ' or ' cJiolesterine disease,' believing that the essen- 

 tial character of the degeneration consists in the development of 

 a peculiar fatty or lardaceous matter of the nature of clioles- 

 lerine : (3.) The more extended and definite examinations by 

 Friedreich and Kekule have shown that the substance of the 

 purest amyloid degeneration more closely resembles the alhumi- 

 nous prijicijjles than any other substance we know of ; and (4.) 

 Schmidt has arrived at the same conclusion. The question, 

 therefore, is not yet definitely settled as to the exact nature of 

 the substance into which the tissues are transformed in the so- 

 called amyloid degeneration ; but the weight of evidence points 

 to its being alliimen in some form." The conclusions that the 

 material is allied to albumen are confirmed more recently by 

 Klihne, who, by submitting the amyloid organs to a process of 

 artificial digestion, has completely succeeded in isolating the 

 new material, and has thus been able to determine its albumi- 

 nous nature. Starch-like bodies (the corpora amylacea) have 

 been discovered in various parts of the body, more especially in 

 the nervous system, the ependyma of the ventricles, the white 

 substance of the brain, the choroid plexus, the optic nerve and 

 retina, and the spinal cord of the aged ; and larger varieties of 

 the same bodies in the prostate gland of almost every adult, 

 accumulating here sometimes to such an extent as to form large 

 concretions. 



The characteristic feature of amyloid is its reaction with 

 iodine, iodine and sulphuric acid, and methylaniline violet. A 

 solution of iodine applied to the amyloid organ causes the affected 

 portions to change to a deep reddish brown colour, which 

 is not, however, permanent, but gradually passes off, and the 

 part regains its former aj)pearance. If the apiDlication of iodine 

 is followed by the cautious addition of sulphuric acid, a blackish 

 blue or violet tint is produced. Great nicety of manipulation 

 is, however, necessary to obtain the reaction of the sulphuric acid- 



General characters of tissues which have undergone the amyloid 

 degeneration. — The cut surface of an organ so affected has a 



