ON BLUE PILL. 163 
tity to these waters is condemned by experience, as not preventing but increas¬ 
ing the tendency to form acetic acid. 
The President expressed concurrence in Mr. Pooley’s opinions. He was strongly im¬ 
pressed with the importance of using distilled water only, even in such case- as the pre¬ 
paration of tinctures. Nothing could be clearer than the error of adding spirit to medi¬ 
cated waters ; a large percentage was, of course, improper, because of its physiological 
action, and a small amount involved certain acidity. With regard to aq. laurocerasi, 
he had found that in spring the very young leaves of the shrub contained but little of the 
volatile and active principles, when at maturity a maximum of these was reached, and 
in autumn it had again declined greatly: he hoped the preparation would soon go out 
of use. 
In reply to Mr. Brevitt, Mr. Pooley stated that he had not made any experiments 
upon preserved flowers. 
Mr. Schacht was glad that the author’s results favoured the use of the volatile oils, 
since every consideration of convenience to the dispenser tended in this direction. In his 
neighbourhood, aq. laurocerasi was much used. It was a critical preparation, and not 
only did the percentage of hydrocyanic acid vary greatly, hut the same might be said of 
its accompanying volatile oil. Since the flavour of this oil was the only ground for the 
use of cherry-laurel water in preference to hydrocyanic acid, a want of uniform compo¬ 
sition was a troublesome fault. After filtration, changes occurred which produced float¬ 
ing particles again. 
Mr. Brady urged the objections that existed to the use of magnesia for the prepara¬ 
tion of medicated waters, since volatile oils were mostly liable to become oxidized when 
acid products resulted. 
Dr. Attfield pointed out further, that even in their fresh and unchanged state, vola¬ 
tile oils were composed of two proximate principles, one a hydrocarbon, and the other an 
oxidized principle, sometimes having qualities of an acid ; thus, pimento oil contained 
very large quantities of eugenic acid. These oils might decompose chalk, and certainly 
would decompose the ordinary basic carbonate of magnesia with production of soluble 
soaps, making the water abnormally and unpleasantly strong. Ground flints, an impal¬ 
pable powder of silica, very largely used at potteries, was the best agent to use in making 
medicinal waters by trituration with essential oil. He took some exception to the method 
adopted in determining the strength of camphor water, and suggested further experi¬ 
ments. 
Dr. Parkinson inquired if copper cisterns had been found to contaminate distilled 
water, but the replies were negative. The same speaker advocated kaolin instead of 
powdered silex. 
Mr. Caswell endorsed the use of kaolin. It was for pimento water that he first tried 
it, in consequence of the troublesome deposit which occurs upon bottles containing this 
water. The result was quite successful. 
Mr. Reynolds said that the choice now appeared to he between kaolin and powdered 
silex, as prepared for pottery. The substitution of fine sand could not be regarded as 
desirable. Some comparative experiments between the two diffusants might soon de¬ 
cide which of them was least open to such objections as choking the filters, etc. 
Mr. Richardson and several other members spoke in favour of the use of ground flint. 
ON BLUE PILL. 
BY MR. F. B. BEXGER. 
The state in which mercury exists in blue pill can be no longer a matter of 
conjecture among Pharmaceutical Chemists. In the present day men are not 
much given to placing implicit confidence in supposititious or popular notions, 
but prove all things for themselves, and it is remarkable that until recently, 
frequent assertions were made in the medical and chemical journals, that the 
efficacy of “ blue pill ” was dependent upon the amount of oxidation which had 
taken place in the metal; it has however been periodically shown that the mer- 
