. ( 84 ) 



§ 6. Tlie beliaviour of cholesterol-isohutyrate is a very remarkable 

 one. Microscopic and macroscopic investigation shows absolutely nothing 

 of an anisotropons liquid phase, not even on sudden cooling and this 

 in spite of the fact that the normal butyrate gives the phenomenon 

 with great splendour. This differently-behaving ester has been prepared 

 from the same bulk of cholesterol as was used for preparing the 

 other esters. The cause of the difference can, therefore, be found only 

 in the structure of the fatty acid-residue, which contrary to that of 

 the other esters, is branched. 



All this induced mo, to prepare the analogous ester of isovaleric 

 acid; perhaps it might be shown also here that the branching of the 

 carbon-chain of the acid destroys the phenomenon of the anisotro- 

 pons liquid phase. At first T thought this w\as indeed the case, but 

 a more accurate observation showed that in the rapid cooling there 

 occurs, if only for an indivisible moment, a hhile anisotropons 

 liquid ; the duration, however, is so short that, for a long time, I 

 was in doubt whether this phase ought to be called stable or labile 

 as in the case of the formiate and capry late! Even though the carbon- 

 branching does not cause a total abrogation of the phenomenon of 

 liquid crystals, the realisable traject appears to become so much smaller 

 by that branching, that it almost approaches to zero, and the expected 

 phase is, moreover, even still labile. From all this I think we may 

 conclude, as has been stated more than once by others, that the occur- 

 rence of the liquid phases is indeed a inherent property of the 

 matter, which cannot be explained by^ the presence of foreign admix- 

 tures etc. (Tammann c. s.). 



§ 7. We now give the melting points of the analogous phytosterol- 

 esters which, with one exception, do not exhibit the phenomenon of 

 the double-refracting liquids. As the phytosterols from different vege- 

 tal)le fats seem to differ from each other, and as B()Mer does not 

 mention any phytosterol esters from Calabar-fat in particular, 1 have 

 indicated in the second cohuim only the limits within which the melting 

 points of the various esters prepared by him from diverse oils, vary, 

 (See table following page.) 



From a comparison of the two tables it will be seen that the lowering 

 of the melting point of phytosterol by the introduction of fatty acid- 

 residues of increasing carbon-content, takes place much- more rapidhj 

 than with cholesterol. On the other hand, the succession of the melting 

 points of the acetate, propionate, butyrate and /i- valerate is more 

 regular than with the cholesterol-derivates. 



All phytosterol-esters share with phytosterol itself the great {qr- 



