Analysis of the Pericarp of the Litliospermum officinale. 25 



seeds resemble small, pear-shaped, porcelain beads ; they are 

 very hard, difficult to break, and have a high polish. AVhen 

 heated, they at first become black ; but they do not shrink, nor 

 does a white heat change their form, in the slightest degree ; it 

 destroys, however, their lustre, and renders them, when the ve- 

 getable matter has been consumed, whiter than they were origi- 

 nally. Before the blowpipe, small pointed fragments of the 

 pericarp may be partially fused ; but this requires a good heat. 



To determine the nature and quantity of the earthy consti- 

 tuents, the pericarps were carefully separated from the enclosed 

 seeds, and exposed to the action of dilute muriatic acid ; a 

 violent effervescence immediately commenced, which did not 

 entirely cease for upwards of two hours. At the end of twelve 

 hours, the acid liquor was decanted, and the pericarps were well 

 washed. Their appearance was not in the least changed ; when 

 dried, at a moderate heat, they still retained their original lustre. 

 The acid liquor was found to contain a great deal of lime, a very 

 little phosphate of lime and oxide of iron, with traces of potash 

 and magnesia, which were separated in the usual manner. 



The pericarps were then heated to destroy the vegetable mat- 

 ter, which it is exceedingly difficult to effect ; but, notwithstand- 

 ing the intense heat employed, the form of the fragments was 

 not changed by it, they merely lost their lustre, and became 

 very white. When the vegetable matter was entirely consumed, 

 they were again treated with muriatic acid, and left in a warm 

 place for several hours. The acid took up a very little phos- 

 phate of lime and oxide of iron. The matter insoluble in the 

 acid, was fused with carbonate of soda, and found to be pure 

 silica. The analysis was repeated, and the composition of the 

 substance appeared to be very uniform. The following is the 

 result : — 



Carbonate of Lime, , . . . . 43.70 



Silica, ....... 16.5 



Vegetable matter, small quantity of phosphate of lime and 



oxide of iron, with traces of potash and magnesia, . 39.8 



100 



The silica appears to form the polished surface of the seeds. 

 As the acid acted upon the vegetable matter of the pericarps, 

 and took up a little phosphate of lime and oxide of iron, that 



