PAULLINIA S0RBIL1S. 
IB 5 
C> - 0 grammes methyl-alcohol, 
8 - 7 grammes iodide of ethyl, 
U-7 
which shows that in this case the less volatile constituent had boiled the faster, the less 
volatile iodide of ethyl having a very much higher vapour-density than methyl-alcohol. 
It will be obvious that when the vapour-densities and tensions are inversely propor¬ 
tional, the mixture must distil over unchanged. This influence of vapour-density goes a 
great way to explain why homologous bodies are so difficult of separation by means of 
fractional distillation. The more complex the formula, the higher the boiling-point, 
but also the higher the vapour-density, and therefore the greater the value of the 
vapour. Why oils, etc., distil so readily in steam is also explamed; for aqueous vapour 
is one of the lightest, while oily vapours are generally heavy. 
VINUM DIURETICUM. 
^ Bacc. Juniperi.partes 50 
Folioruin Digitalis. 10 
Rad. Scillse. 5 
Vini albi.. 750 
Macera per dies quatuor, deinde adde 
Potassae acetatis .partes 15 
et filtra. 
Dose .—Two or three tablespoonfuls daily.— Trousseau , Bulletin de Therapeutiqve. 
SOME ACCOUNT OF PAULLINIA SORBILIS AND ITS PRODUCTS. 
BY T. C. ARCHER, ESQ. 
The author remarked :—There is no more remarkable plant in the Order Sapindacese, 
if regarded from an economic point of view, than Paullinia sorb ills, although, as a 
plant, it is not well known to the botanical world. From its large seeds is manufac¬ 
tured the substance called “ Guarana,” which is extensively used in Brazil, Guate¬ 
mala, Costa-Rica, and other parts of South America, as a nervous stimulant and re¬ 
storative. The seeds deprived of their coverings are pounded into a paste, which, 
hardened in the sun, constitutes Guarana. It is used both as a remedy for various 
diseases, and also as a material for making a most refreshing beverage ; and it adds, 
another of those incidents so puzzling in human history of the discovery of such 
qualities in plants least likely to be suspected : such, for instance, as that the leaves 
of Tea, the seeds of Coffee and Cacao, the leaves and twigs of the various American 
Ilexes, and other plants, should have this wonderful restorative effect on the nervous 
system, and that this should not be a mere vague notion, such as attaches to thousands of 
other plants, but that it should really depend upon the presence of a chemical prin¬ 
ciple, the same in all, and the operation of which can be satisfactory explained. The 
presence of an alkaloid, which he called Guaranine, was discovered some years ago in 
Guarana by Dr. Theodore von Martius, of Erlangen, but its identity with tlieine was 
soon established, and subsequent analyses, especially one by Dr. Stenhouse in 1856, 
proved that not only was the active principle of Guarana identical with Tlieine, but 
that, as far as is known, no other substance yields it so abundantly, the amount being 
5 - 07 percent, as against good black tea, which yields 2T3, and coffee from 0'8 to l'OO. 
The mode of using the Guarana is curious and interesting. It is carried in the pocket 
of almost every traveller, and with it the palate bone or a scale of the large fish (Sudis 
gigas), locally called “ pirarucu,” the rough surfaces of which form a rasp upon which 
the Guarana is grated, and a few grains of the powder so formed are added to water, 
and drunk as a substitute for tea. The effect is very agreeable, but as there is a large 
