For pharmaceutical purposes crude petroleum is no longer generally used by civilized races, though the product vaseline is largely employed in this way, and emulsions of petroleum have been administered internally in various pectoral complaints; while the volatile product termed rhigolene has been largely used as a local anaesthetic.
Externally chloroforrr ‘ is an antiseptic, a local anaesthetic if allowed to evaporate, and a rubefacient, causing the vessels of the skin to dilate, if rubbed in.
The uses of chloroform which fall to be mentioned here are: - as a counter-irritant; as a local anaesthetic for toothache due to caries, it being applied on a cotton wool plug which is inserted into the carious cavity; as an antispasmodic in tetanus and hydrophobia; and as the best and most immediate and effective antidote in cases of strychnine poisoning.
It acts similarly, though less markedly, upon the nerves which determine the secretion of the perspiration, and is therefore a local anaesthetic or anodyne and an anhidrotic. Being rapidly absorbed into the blood, it exercises a long and highly important series of actions on nearly every part and function of the nervous system.
Its use as a local anaesthetic (see Anaesthesia) makes it the most valuable of the coca alkaloids, and it is much used in ophthalmic practice.