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liquid phases) possess such ethylene double bonds, one might indeed 

 imagine thai the presence thereof in the molecule is of great 

 importance for the occurrence of the said phenomena, if not the 

 conditio sine qua non, as the structure of the azoxy-compounds is 

 not yet firmly established and because it may be assumed that they 

 contain, perhaps, similar double bonds between N and 0. 



Moreover, the cholesterol esters all contain three liquid phases, so 

 that this peculiar complication might perhaps also be connected with 

 the possibility of very intricated isomerism-phenomena of those 

 substances. 



§ 4. In order to answer these questions, I asked Prof. Dr. C. Neuberg 

 of Berlin to furnish me with a specimen of his synthetic Dihydro- 

 cholesterol, to which request this savant most willingly acceded. 



I wish to thank Prof. Kei berg once more for his kindness. 



In this DihydrOcholesterol the ethylene double bond has disappeared 

 owing to the addition of two atoms of hydrogen, and the malenoid 

 and fumaroid isomerism is therefore, a priori excluded. 



§5. I have prepared from this alcohol the acetic and the normal 

 butyric esters, by means of the pure acid-anhydrides, and have 

 examined the same as to their phase transitions. The acetic ester 

 will be described elsewhere later on; here the butyric ester only 

 will be discussed. 



As a highly important result I may mention that the colour pheno- 

 mena on melting and the occurrence of three liquid modifications in 

 the normal butyrate remain unaltered as before, but that the irre- 

 versibility of the phase-transitions is shown in a manner just the 

 reverse as in the case of most of the cholesterol esters, e.g. the laurate. 



Whereas of the tw T o doubly-refracting liquid phases of the last 

 named substance, one is always passed over on cooling, whilst both 

 are found on melting the solid substance, this is just the reverse 

 in the case of the dihydrocholesterol-?z-butyrate. 



6. The solid phase S consists of an aggregate of very thin, 

 colourless, and clear transparent laminae in which the plane of polari- 

 sation makes an obtuse angle with the sides of demarcation and 

 exhibit in convergent polarised light a hyperbole with very strong 

 colour dispersion q ^> v. 



On heating, this phase S passes into a doubly-refracting liquid B, 

 consisting of very small, feebly doubly-refracting individuals, which 

 in turn passes at a higher temperature into the isotropous fusion L. 



