359 



On the Myelins, Myelin Bodies, and Potential Fluid Crystals 



of the Organism. 



By J. G-. Ad ami, F.E.S., Montreal, and L. Aschoff, Marburg. 

 (Eeceived June 6, — Read June 7, 1906.) 

 (From the Pathological Institute of the University of Marburg.) 



When, in 1854, Virchow recognised myelin as, if not a single substance 

 identical with the essential constituent of the medulla of nerves, at least as 

 a class of substances which chemically were closely allied thereto, he 

 described it as possessing the following characteristics : — 



(i) When brought into contact with water it swells up, exhibiting a 

 characteristic morphology, and developing processes of irregular and bizarre 

 form having a double contour. 



(ii) Easily soluble in hot alcohol, becoming in part precipitated on cooling. 



(iii) Rapidly dissolved in ether, chloroform, and turpentine. 



(iv) Acted upon but slowly and to a slight extent by weak acids and 

 alkalies. 



(v) Undergoing shrinkage under the action of strong alkalies, with loss of 

 characteristic properties. 



(vi) Swelling greatly under the action of concentrated sulphuric and other 

 strong acids, with eventual dissolution. 



Substances possessing these properties to a greater or less extent, and 

 especially the property of swelling in water and exhibiting " myelin forms," 

 have been recorded during the last 50 years as occurring in very many 

 organs, and these either under physiological or under pathological conditions. 

 How widespread they are is indicated by the following table, which we give 

 because we have not met with any attempt at a full classification in the 

 recent literature of the subject : — 



I. Intracellular Myelin Bodies. — These are small, highly retractile bodies 

 situated within the cytoplasm, which, under the action of water or physio- 

 logical salt solution, swell up and assume irregular forms. According to the 

 conditions under which they are found they may be redivided into — 



A. Physiological, or associated with normal regressive processes, in — 



The suprarenal cortex of man and of several vertebrates (Kaiserling 



and Orgler). 

 The granular cells of the corpora lutea (Do.). 

 The thymus gland (Do.). 



