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Dr. W. Ord. Experiments on the [June 19, 



may be compared to the whipping of an egg. In another, it may be 

 compared with the cleavage of the ovum after impregnation. In the 

 ovum up to the time of impregnation the contents of the zona pelku 

 cida form one sphere. After impregnation, after the introduction of 

 a material having the power of inducing new activities, shrinkage is 

 followed by movements having the character of a gradual peristalsis, 

 and subsequent fissions reduce the sphere to the mulberry mass of 

 small equal spherules. 



Regarded from another point of view, we see a series of movements 

 resulting from the tendency of matter to come to rest. We see 

 stages which may be compared to the spring of the bow when the 

 drawn string is let go ; and, again, to the straightening of the un- 

 strung bow. Or we may see in the chain of movements, beginning 

 with the formation of the sphere and ending in the crystal at rest, 

 a parallel to the chain of force formed when water is raised by 

 the sun to the clouds and hill-tops to descend in rain or rivers to the 

 sea — to rest; or to the chemical chain in which oxygen and carbon, 

 torn asunder by light within vegetables, slowly recompose carbonic 

 acid within animals, and in turn come to rest. 



Here, again, the question is suggested to me, how far may 

 the simpler movements of the constituents of animal and vegetable 

 organisms be due (among other things) to the struggle of one group 

 of substances against the grasp of another, to the tendency of each 

 substance to ultimate complete separation from the substances with 

 which it is intermixed, and to the tendency of each separated sub- 

 stance to assume the nearest possible approach to a static condition ? 



The observations have, however, an immediate practical relation 

 to the structure of such biliary calculi as are composed chiefly of 

 cholesterin. Such calculi are seen in sections to be composed of 

 several distinct stratifications. Most commonly they have (1) a 

 thin rugged outer layer, deeply tinged with bile colour ; within 

 this (2) a brown portion marked with concentric lines correspond- 

 ing to laminae ; within this (3) a lighter- coloured layer, presenting 

 radiating markings or distinct radiating fissures between crystalline 

 columns ; and, lastly (4), at the centre a mass of deep colour and 

 friable consistence (fig. 37). The strata are not sharply defined 

 from each other, but are joined by transitional layers. They differ 

 severally in minute structure. In the outer crust (1) distinct 

 independent spherules and spheroidal masses composed of cholesterin, 

 mixed with mucus and bile-pigment, can be seen (figs. 27 — 31). In 

 the concentric layers (2) the microscope shows a substance pretty 

 uniformly inter- penetrated by, and partially coloured with, pigment; 

 it is marked with radiating crystalline fibrations of varying degrees of 

 fineness running sinuously at right angles to the concentric markings ; 

 in fact, it shows a combination of concentric and radiating arrange- 



