174 Proceedings of the Royal Society of Edinburgh. [Sess. 
Finally, Kipping and Pope * observed that the addition of c£-glucose to 
a solution of sodium chlorate always caused a preponderance of dextro- 
rotatory crystals of sodium chlorate to separate out on spontaneous 
crystallisation ; and later, they extended their experiments to solutions of 
sodium ammonium racemate.f 
In this case also they found that a solution of sodium ammonium 
racemate to which <i-glucose had been added, if allowed to crystallise 
spontaneously below 27° C. (i.e. at a temperature at which the racemate is 
the unstable form and the tartrates the stable form), always deposited 
crystals of d- tartrate in greater quantity than of ^-tartrate ; in some of the 
experiments almost pure d- tartrate was obtained. 
It is difficult to see in what way the sugar brings about this result. 
In view of the results of the researches mentioned above on the solubility 
of optically-active stereoisomers in optically-active liquids, investigations 
which were subsequent to and, in all probability, consequent upon these 
crystallisation experiments of Kipping and Pope, the glucose cannot be 
considered to diminish the solubility of the dextro-salt, nor yet to form a 
more soluble complex with the laevo-salt. If the aqueous solution of sugar 
be looked upon as an optically-active solvent for the salt, it is not easy to 
see why an optically-active liquid, which is at the same time a pure 
substance, does not cause an inactive d + 1 mixture to deposit on crystallisa- 
tion an excess of the one or the other isomer ; nevertheless H. O. Jones j 
was unable to obtain any trace of separations of inactive camphoroxim, or 
of inactive mandelic acid by crystallisation of its solutions of them in 
d-pinene. 
Whatever the explanation may be, the interesting fact remains that 
the glucose influenced the two optically-active isomers in a different manner 
or to a different extent. 
The experiments described in this paper were directed to the mixed 
solutions of the two independent optically-active substances rather than to 
the heterogeneous systems-solid and solution, certain physical properties 
of the solutions being measured in order to find out if there were any 
recognisable differences in the two sets of solutions. 
* Ghem. Soc. Jour., 73, p. 606, 1898. 
t Proc. Ghem . Soc., 1898, p. 113. 
| Loc. cit. 
