ATROPHY 395 



It has been suggested that the chsappcarance of rigor mortis depends 

 upon beginning autolysis of the clot by the intracellular proteases of 

 the muscle, which act best in an acid medium, but proteoses and 

 peptones cannot be found in such muscle. It is improbable that the 

 degree of acidit}' ever becomes so high that the myosin is redis- 

 solved through a conversion into acid albumin (syntonin), as was 

 formerly supposed, v. Fiirth holds that the re-solution of the rigor is 

 caused by coagulation of the proteins, thus reducing this hydrophilic 

 tendency, a view in harmony with recent developments in colloid 

 chemistr}'." 



"Waxy" degeneration of muscles, although usually resulting from 

 the action of toxic substances, is entirely different from cloudy swell- 

 ing, in that the cytoplasm has become homogeneous and not granular. 

 This is undoubtedly due to the increased accumulation of acid which 

 takes place in muscles when they suffer from a defective oxygen sup- 

 ply, for I have found it possible to produce the typical appearance 

 of Zenker's waxy degeneration by letting weak solutions of lactic 

 or other acids act on muscle fibers. Even excessive stimulation of 

 muscles was found to be sufficient to cause waxy degeneration, the 

 acid being formed faster than it can be removed. ^^ 



Muscles showing the "reaction of degeneration" have been anal3'zed by 

 Rumpf and Schumm,'^* who found a great increase in the fatty matter, which was 

 about fifteen times the normal amount. The muscle, deducting the fat, showed 

 a loss of solid matter and an increase of water; sodium and calcium were increased, 

 potassium decreased. There is also a great relative increase in the proportion of 

 phosphorus bound to protein in muscles which have atrophied after nerve section, 

 because of the persistence of nuclear and loss of non-nuclear elements (Grund"®), 

 but there is little change in the proportion of mono- and di-amino nitrogen.^' 

 The creatine content decreases steadily after the reaction of degeneration is first 

 well established.^* 



ATROPHY 



The chemical changes of simple atrophy have not, so far as I can 

 find, been definitely studied. It is to be presumed, in view of the 

 structural changes, that analysis of atrophied tissues would show a 

 relatively high nucleic acid and collagen content. It is known that in 

 atrophy the cell lipoids are not much altered, while the simpler fats 

 maj^ be increased in parenchymatous organs. In fatty tissues, of 

 course, the fat is greatly reduced, its place being partly taken by 

 serum (serous atrophy of fat). In the heart muscle, especially, but 



^' Corroborated by Lentz, Zeit. angew. Chem., 1912 (25), 1513; and Schwarz, 

 Biochem. Zeit., 1912 (37), 35. 



"^ As this work antedates much of the recent work on the influence of acids of 

 metabolic origin upon the swelling of cell structures, attention may be called to 

 the fact that a preliminary report of these experiments w-as made in the first 

 edition of this book, written in 1906. 



«5 Deut. Zeit. f. Xervenheilk., 1901 (20), 445. 



«« Arch. exp. Path., 1912 (67), 393. 



" Wakeman, Jour. Biol. Chem., 1908 (4), 137. 



" Cathcart et al, Jour. Phvsiol., 1918 (52), 70. 



