ON HOME-GROWN PODOPHYLLUM AND JALAP. 
461 
sp. gr. 0845, for six days, with occasional agitation. It was then transferred 
to a percolator, and the percolation continued till a few drops of the fluid, when 
evaporated, left but a slight residue, which was soluble in water. The spirit 
was distilled off till the liquid was of a syrupy consistence, and it was then 
poured into about eight times its bulk of distilled water, constantly stirring. 
The light yellow flocculent precipitate which fell down was allowed to stand for 
twenty-four hours, then filtered off and dried. The concentrated filtrate was 
added to twice its bulk of water, acidulated with hydrochloric acid. The pre¬ 
cipitate, consisting of muriate of berberine and probably also of a little resin 
which had not been previously precipitated, was collected as before. 
Resin precipitated by water, 12*543 grs. = 4*02 per cent. 
Precipitated by HC1, 1*641 grs. = 0*52 „ 
Mr. Tichborne, who at my request kindly undertook the analysis of another 
portion, obtained by the process of the British Pharmacopoeia, 4*8 per cent, of 
resin, besides a small additional quantity of hydrochlorate of berberine. 
In a previous experiment I found that one day’s maceration before the perco¬ 
lation did not answer so well, and that a less amount of resin was the result. 
For some reasons I thought it possible that the resin might include sulphur as a 
constituent, but an experiment performed with that view gave negative results. 
It is worth noticing, that the solution of the resin in nitric acid was at first of 
a clear deep red, and that the addition of a little water caused a greyish-yellow 
precipitate ; the solution ultimately became green. The resin of jalap, when 
similarly treated, gave a yellow solution with nitric acid, and a milky-white 
precipitate on the addition of water. 
From the foregoing analyses it will be seen, that the percentage of resin is 
good, and is fully equal to that of American podophyllum, which Parrish states 
at 3*75 per cent., and Wood gives as varying from 3*12 to 5*25 per cent. This 
high yield of resin is the more remarkable, since the soil of the Botanic Gardens 
is dry, though the plant naturally favours moist shady woods or low damp 
situations, and is only occasionally found in dry and exposed localities. The 
apparent percentage of resinoid matter is sometimes fictitiously increased by 
the practice of adding alum or other reagents, in order to promote the precipi¬ 
tation of the resin. 
Mr. J. Spearing found alumina in five out of twelve commercial specimens ; 
two contained iron, and one copper. A specimen that 1 have in my collection 
contains both alumina and lime. It is probable that the exceptionally dry and 
hot summer through which we have passed, was not without influence on the 
secretion of resinous products, such as those under discussion. Thus, the mean 
temperatures at Dublin for the months of May, June, and July, of the past 
summer, were 52*37, 58*20, and 60*21, answering respectively to 51*89, 58*03, 
and 59 84, the mean for the four years preceding. 
According to Mr. Glaisher, “ there is no instance in ninety-eight years of so 
high a mean temperature in the corresponding quarter (July, August, Septem¬ 
ber), as in the present year.” The deficiency of rain during these three months 
amounted to two and a half inches. A striking instance of the prevailing high 
temperature of the summer months was afforded by the unusually fine growth 
of the castor-oil plant, a native of the East Indies and north of Africa, which 
reached a height of six or seven feet, and produced seeds in October, many of 
which nearly approached maturation, and exhibited their characteristic mark¬ 
ings. But the point which it was of greatest interest to ascertain was, whether 
the resinoid principle was possessed of physiological activity equal to that of 
American podophyllum, and to this end the following experiments were made :— 
