Professor Wilson, in a notice on the medical science of the Hindoos, published in the Oriental Magazine, examines into the distinctive qualities of the various sorts of leeches, and shows that the description given in Avicenna, in the section “De Sanguisugis,” is almost identical with the Hindoo author’s description of the twelve sorts of leeches, in distinguishing the appearance and properties of the various sorts.

That this is more than a mere coincidence is clear from the fact that Avicenna says “Indi dixerunt.”

I do not think it will be seriously disputed that the Arabs had access to the Hindoo works of and before their time, and we will find, if we carefully examine the subject, that the science of medicine as distinguished from surgery, and of chemistry as a part of that science of medicine, was much more ancient than we have been prepared to admit.

It would be incredible to believe that amongst a people so observant and highly cultured as the Brahmins must have been, that medicine and the changes occurring in mixtures of various substances should have been unstudied, and there is no doubt that this subject was far from being neglected by them.

Many natural productions of the country, such as nitrate of potash, borax, carbonate and sulphate of soda, sulphate of iron, alum, common salt, and sulphur, could scarcely escape the notice of even ordinary men; but Dr. Ainslie has shown, from the evidence of old Indian medical works, that they were not only acquainted with ammonia (which they made by distilling salammoniac one part, and chalk two parts), but that they prepared sulphuric acid by burning sulphur and nitre together in earthen pots, calling it Gunduk Ka Attar, or “attar of sulphur.”  Nitric acid, which was prepared, not by the process described by Geber, but by mixing saltpetre, alum, and a portion of a liquor obtained by spreading cloths over the common gram plant, and leaving them exposed to the dew, when they were found to absorb the acid salt so abundantly secreted by the plant on the surface of its leaves, and which, when examined by Vauquelin, was found to contain both oxalic and acetic acids.

Muriatic acid was also made by distilling alum and common salt, dried and pounded with the above acid liquor.

Arsenic was used by them for the cure of palsy, and also for venereal diseases, and is still used by them for this purpose, and in intermittent fevers.

It would occupy too much time to go further into this subject at the present time, but there are many chemical compounds which are still made and sold in the Indian bazaars which have been used from time immemorial, and which require a knowledge of chemical manipulation in the arts of subliming, distilling, &c.

Mr. Rodwell says, “that the distillation of cinnabar with iron, described by Dioscorides, is the first crude example of distillation, which afterwards became a principal operation among the alchemists and chemists for separating the volatile from the fixed.”