76 ORGANIC CONSTITUENTS. 



to about the twentietli part^ and the still hot concentrated ley 

 then reduced to dryness in a retort. 



" The saline mass obtained in this manner consists of two por- 

 tionSj one easy, the other difficult of solution. The more so- 

 luble portion consists, according to circumstances, of butyrate 

 and caproate of baryta, or solely of the barytic salt of vaccinic 

 acid ; but in this case there is little or no butyric or caproic 

 acid present. The portion difficult of solution consists of the 

 baryta salts of two distinct acids, which Chevreul described to- 

 gether as caprate of baryta. The more insoluble portion 

 amounts to about the twentieth part of the soluble, and the en- 

 tire mass to about the tenth part of the saponified butter. To 

 separate the diff'erent salts, the residuary saline mass is boiled 

 with about 5 or 6 parts of water ; one portion dissolves, the other 

 remains behind. The solution of the readily soluble salts is set 

 aside to crystallize; if, on the first crystallization, the crystals 

 which separate have the appearance of benzoate of lime, and do 

 not effloresce, i. e. if they are caproate of baryta, the butyrate of 

 baryta has still to be sought for in the solution ; but if nests of 

 small crj^stals form, which quickly effloresce, and resemble nests 

 of the native carbonate of lime, it is vaccinate of baryta, and it 

 is then unnecessary to look for butyrate and caproate of baryta. 



" The circumstances under which butter contains vaccinic acid 

 or butyric and caproic acids are not known. The butter of 

 1842, and likewise that of the following winter, contained, in 

 several experiments, not a trace of any other easily soluble salt 

 of baryta than the vaccinate ; while the butter in the summer 

 of 1843 contained no vaccinic acid, but only the other two. 



" The soluble saline mass, containing the but^nric and caproic 

 acids is dissolved in water and evaporated to crystallization, in 

 order to separate them. Long silky needles, aggregated in 

 bundles, separate even in the first crystallizations ; and if the 

 solution has been sufficiently concentrated, nearly the wJiole of 

 the caproate salt is deposited. The entire solution solidifies to 

 a paste of minute needles, which ai'c separated by pressure from 

 the mother-ley, and purified by recrystallization. The remaining 

 ley is now allowed to crystallize spontaneously, which is best 

 eff'ected b}^ exposure to the sun ; at first a little caproate of ba- 

 ryta still separates, the form of the crystal then changes, laminae 

 of mother-of-pearl lustre make their appearance, and all the 



