THE MYELINS 169 



cross between four illuminated sectors. Smear a little of the 

 juice of the fresh adrenal on a slide, and these can be examined 

 more narrowly. Under the ordinary lens that juice is found 

 filled with pure fatty globules varying in size ; with the crossed 

 Nicol's prisms a few of these now stand out as illuminated 

 crosses. Turn the prism round, and what had been crosses 

 appear indistinguishable from the abundant surrounding fatty 

 globules (Plate II. Fig. 1). 



Here clearly we have not to do with ordinary fats. Neutral 

 fats and fatty acids under no condition afford these charac- 

 teristic doubly refractive globules. We are dealing with some 

 other substance, a substance apparently acted on by water, 

 for the addition of water to the juice causes the crosses to fade 

 out ; they disappear also if the preparation be desiccated, as 

 again rapidly if it be treated with absolute alcohol. By that 

 apparently they are dissolved, for treat an adrenal with alcohol 

 and now evaporate that alcohol and at a certain stage these 

 doubly refractive globules make their appearance to disappear 

 again as the preparation dries up. Where an adrenal has been 

 hardened in formalin, minute rod-like crystals take the place of 

 these globules. 



The adrenal is far from being the only organ that affords 

 them, although it is the organ which in the normal state affords 

 them in the greatest abundance without previous treatment of 

 any kind. A common morbid state that often yields them in 

 great abundance is atheroma of the aorta — one has but to scrape 

 off a little of the broken-down material in an atheromatous 

 plaque to find again this association of isotropous fatty and 

 doubly refractive anisotropous globules. Or, again, pound up 

 the liver or the spleen or the kidney in absolute alcohol, leave 

 for a few hours, put a drop or two of the fluid on a slide, and 

 as the alcohol evaporates these remarkable bodies make their 

 appearance in relatively large numbers (Plate II. Fig. 2). 



What are they and what do they signify % 



The answer to that question is rather a long story, and a 

 round-about-one at that ; nor as yet is it in my power — or any 

 one's — to tell you its conclusion. The most I can hope to do is 

 to interest you in the story, to show you mto what by-paths of 



