407. _In Gonorrhœa and Vaginal Discharges_ the above solution is an excellent application, though not so uniformly useful as in Ophthalmia. In Gonorrhœa, it may be commenced with at once, the injections being repeated frequently during the day, in addition to general remedies; but in Vaginal discharges other remedies may be tried first. (See _Index._) 408. Sugar is an excellent dressing for certain forms of _Foul, Gangrenous looking Ulcers_, the Sugar (white or refined) in grain being merely sprinkled over the sore, which under its use soon assumes a healthy appearance. As a drawing plaster for _Boils_ equal parts of Sugar and Yellow Soap, is an old remedy. (Dr. Aitchison.) 409. +Petroleum. Rock Oil.+ Mittí-ká-tél (_Hind._, _Duk._), Mátiyá-tail (_Beng._), Man-yenney, Man-tayilam (_Tam._, _Mal._), Manti-tayilam, Manti-núné (_Tel._), Mannunyanné (_Can._), Mattí-cha-téla (_Mah._), Mattí-nu-tel (_Guz._), Yé-ná (_Burm._). 409_a_. Petroleum, a mineral oil, semi-liquid, somewhat of the consistence of treacle, tenacious, semi-transparent, of a deep sherry red or nearly opaque, tar-like brown, with a peculiar though not unpleasant aromatic odour and pungent acrid taste, exudes spontaneously from the rocks in volcanic regions, and collects on the surface of certain lakes in Persia, Burmah, Assam, and the islands on the Arracan Coast, as well as in Barbadoes, Trinidad, and other West Indian Islands. As a medicinal agent, it is a terebinthinate (turpentine-like) stimulant, and as such appears to act specially on the kidneys, increasing in a marked degree the urinary secretion. The dose is about half a fluid drachm (thirty drops) suspended in mucilage. 410. Petroleum is very generally employed by the Native practitioners externally as a stimulant in _Paralytic Affections_ and in _Chronic Rheumatism_, and Dr. Fleming (Cat. p. 53), commenting on this, adds that he can, from his own experience, recommend it in the latter disease as an efficacious remedy, having derived more benefit from it than from the more costly Cajeput Oil, which he had previously used. A case of _Beri-beri_ successfully treated by it, externally and internally, is recorded by Mr. S. Arokeum (_Madras Quart. Med. Journ._, July 1863), but how far the recovery was due in this instance to the Petroleum seems doubtful. Still, it seems worthy of further trials in this obscure affection. 411. _In Skin Diseases_, it is a useful external application, and a case of _Chronic Eczema_, which had resisted a host of remedies cured by it, is recorded by Dr. J. W. Mudge (_Indian Ann. of Med. Science_, 1854, p. 450). He used it incorporated with Soap in the proportion of a drachm to an ounce.