( 489 ) 



heating of a .solid substance S above its inviting point without fusion 

 taking place. For the present, at least according to existing ideas, this 

 behaviour can only be explained by assuming the presence of a two- 

 component-system with tautomeric transformations subject to a strong- 

 retardation. 



When the isotropous fusion L which has scarcely cooled to a few 

 doubly-refracting drops is melted cautiously, we may observe some- 

 times that where a moment before the strongly luminous, yellowish- 

 white globules were visible, there are now present greyish globules 

 showing the black cross, which gradually decrease in size and also 

 darken, to disappear finally as (isotropous?) little globules in the 

 isotropous fusion 1 ). This phenomenon, in connection with those of 

 crystallised ferric chloride to be described later, and with similar 

 phenomena observed with the cholesterol esters appears to me to 

 have great significance for the theory of the formation of liquid crystals. 



§ 9. Finally, there is something to be observed as to the separation 

 of a-Phytosterol-valerate from organic solvents. The substance may 

 be obtained from ethyl acetate -j- a little alcohol in beautiful, hard, 

 well-formed little crystals. If, however, the saturated cold solution 

 in ethyl acetate is mixed with much acetone (in which the substance 

 is but sparingly soluble) the liquid suddenly becomes a milky-white 

 emulsion which deposits the compound not as a tine powder, but in 

 the form of a doubly-refracting, very thick and very sticky liquid. 



I have repeated this precipitation in a hollow object glass under 

 the microscope. The emulsion consists of a very great number of 

 doubly-refracting, globular liquid-globules, which are either moving 

 about rapidly in the liquid, or, when united to larger masses, are 

 quite identical with the ordinary anisotropous phase A, when this 

 is cooled to the temperature of the room. These little globules all 

 exhibit the cross of the spherolites, and the doubly-refracting liquids. 

 They soon become solid and then form small needles and spherolitic 

 aggregations. It may be easily proved by stirring that the globules 

 deposited first are liquid ; moreover, the doubly-refracting masses 

 often communicate with each other by means of very narrow, doublx - 

 refracting currents, while they often exhibit the phenomena of pseudo- 

 isotropism. 



Therefore, we have evidently obtained here the liquid-anisotropous 



] ) Before that happens, we may sometimes see here the globules becoming 

 enlarged to multiplets by amalgamation there larger ones being changed into 

 .smaller ones, sometimes lure one disappearing in the liquid while very close bj 

 new individuals appear. 



