( 362 ) 



sterjl-esters usually display the phenomena of the doubly-refracting 

 liquid-conditions. All this seems probable to the investigator, the more 

 so as it has been proved by Lehmann, that in my other cholesteryl- 

 esters, even in the case of the caprinate, botli or one of the two 

 anisotropous liquid-phases were always labile and only realizable on 

 undercooling; some of them, such as the «^(^butyrate, only exhibited 

 their labile anisotropous liquid-phases, when containing some impurities 

 and not when in a pure condition. With the idea of a gradual 

 dissociation of compound molecule-complexes into more simple ones, 

 agrees the fact that the anisotropous liquid phases have never been 

 known yet to occur after the isotropous ones ; this is alwaj^s the 

 end-phenomenon, which is accounted for by the fact that a dissocia- 

 tion of this kind is always found to increase with a rise of temperature. 



That the cooling between solid and anisotropous-liquid does not 

 proceed so suddenly as may be predicted from the great calorific 

 effect is shown in the case of the cinnamylate from the fact that, 

 after the solidification, particularly at the side of the test tubes, the 

 interference-colours, which are characteristic before the transition of 

 the phases into each other, remain visible for a very long time, 

 often many hours, then slowly disappear. Even with great enlarge- 

 ment, no well defined crystals can be discovered in those coloured 

 parts ; the whole conveys the impression of a doubly-refracting, irre- 

 gular network of solidified liquid droplets, just like the liquid crystals 

 which present themselves to the eye with the aid af a powerful 

 enlargement ^). 



In these obscure phenomena we are bound to notice the more or 

 less labile and partially realized intermediate stadia in a continuous 

 transition liquid t^ solid. The view expressed by IjEHmann, that there 

 should be present a difference between the kinds of molecules in 

 the different aggregate conditions, is adopted here with this difference, 

 that such a difference of association of the molecules is thought quite 

 compatible with the phenomenon of the continuity of the aggregate 

 conditions, treated of here. 



§ 3. I wish to observe, finally, that cholesteryl-cinnamy late when 



subjected frequently to these melting experiments, soon undergoes 



a small but gradually increasing decomposition, which shows itself 



in the yellow colour of the mass and the fall of the characteristic 



temperature-limits. 



Zaandam, 26 Oct. '06. 



1; A still more dislinct case of this [jheiiomeiion has now been found by me 

 in ^.-phytosteryl-propionate, which 1 hope soon to discuss in another communication. 



