( 86 ) 



Accordinp,- to Prof. Lehmann, normal phjtosterol-valerate forms 

 very beautiful liquid crystals, which are analogous to tliose of chole- 

 sterol-oleate ; like these they are not formed until the fused mass is 

 undercooled. Consequently, the anisotropous liquid phase is here also 

 labile in regard to the isotropous one. 



I do not think it at all improbable that the changes in the melting 

 points observed by Schey with his higher tryglicerides also owe 

 their origin to the occurrence of labile, double-refracting liquid phases. 

 A further investigation is certainly desirable. 



§ 8. We now arrive at the discussion of the mutual behaviour 

 of both series of fatty esters in I'egard to each other. 



It has been sufiiciently proved by Bomer that the meltingpoint- 

 line of cholesterol and of phytosterol is a rising line. In connection 

 with Mügge's and my own crystal determinations w^e should have 

 here indeed a gradual mixing between heterosymmetric components ! 

 In mixtures which contain about 3 parts of cholesterol to 1 part 

 of phytosterol, the microscopical research appears to point to a new 

 solid phase, which seems to crystallise in trigonal prisms. This com- 

 pound (?) also occurs with a larger proportion of cholesterol ^). Whether 

 we must conclude that there is a iniscibility of this new kind of 

 crystal with both comjionents, or whether an eventual transformation 

 in the solid mixing phases proceeds so slowly that a transition 

 poijit in the meltingpoint-line escapes observation, cannot be decided 

 at present. 



The matter is of more interest with the esters of both substances. 

 According to Bomer ^) the formiates give a meltingpoint-line with a 

 eutectic point ; the acetates, however, a continuously rising melting 

 point-line. 



The method of experimenting and the theoretical interpretation is, 

 however, rather ambiguous, as Bomer prepares mixed solutions of 

 the components, allows these to crystallise and determines the melt- 

 ingpoint of the solid phase tirst deposited. By his statement of the 

 proportion of the components in the solution used, he also gives an 

 incompletfc and confusing idea of the connection between the melting- 

 point and the concentration. 



Although a rising of the binary meltingpoint-line may, of course, 

 be ascertained in this manner quite as well as by otiier means 

 — and Bömer's merit certainly lies in the discovery of the fact 



1) Compare Bomer, Z. f. Nalir. u. Gen. M. (1901) 546. 



2) BöMER, Z. f. Nahr. u. Gen. Mitt. (1901) 1070. In connection with tlie dimor- 

 phism of the formiates, a mixing series witli a blank is however very probable in 

 this case. 



