Pharmacology

Perhaps the most important internal disinfectant to be dis covered is the compound "Bayer 205," a derivative of the dye trypan blue. This substance has a powerful action both in pre venting and relieving the trypanosomal disease sleeping sickness (q.v.), the worst scourge of tropical Africa.

Mollgaard showed recently that an organic compound of gold, sodium aurithiosulphate, named "sanocrysin" can produce very remarkable curative effects, in a certain proportion of cases of tuberculosis (q.v.), but is equally capable of producing deleterious effects, and therefore great care is needed in its administration.

Antiseptics.

The special conditions of World War surgery made the discovery of powerful wound disinfectants an urgent problem, and a number of new disinfectant compounds of great activity were discovered, for example the dye "acriflavine," and the quinine derivatives "vuzin" and "optochin" (see ANTISEPTICS).

Although the synthesis of the alkaloid quinine has not yet been effected, nevertheless its chemical structure is known, and it is possible to modify the structure of the alkaloid and thus produce new compounds. Vuzin and optochin are two quinine derivatives which differ from quinine in having a far more potent disinfectant action on bacteria. Another important new wound disinfectant is chloramine-T, an organic chlorine compound which acts by slowly liberating chlorine. The disinfection of the kidney and the bladder is another important problem in which advances recently have been made. A new organic compound termed hexyl resorcinol appears to be a very powerful urinary' disinfectant.

Use of Active Principles.

Most of the advances mentioned hitherto have depended upon the discovery of new synthetic organic compounds of greater potency than any known hitherto, but cures for other diseases have been discovered by substituting purified active principles for crude vegetable extracts.

Ipecacuanha has been known for more than a century to benefit amoebic dysentery, but the administration of the drug by mouth was limited by its action as an emetic. Sir Leonard Rogers showed in 1912 that subcutaneous injections of the alkaloid emetine, the chief active principle present in ipecacuanha, usually produced a rapid cure in cases of amoebic dysentery (see DYSENTERY).

Similarly, it has been known for many years that leprosy (q.v.) is often benefited by administration of Chaulmoogra oil, but it was found impossible to administer large doses of this oil by mouth on account of its irritant properties. Organic chemists isolated from Chaulmoogra oil certain complex fatty acids named hydnocarpic and chaulmoogric acids, which were believed to be the chief active principles present in the oil. Sir Leonard Rogers in India and Heiser in the Philippines introduced the method of injecting prep arations of these purified fatty acids intravenously or intramus cularly and obtained remarkable curative effects even in the cases of leprosy of many years' duration (see LEPROSY). The most striking recent successes of pharmacology have been achieved in the cure of infectious diseases, because in most other serious diseases some vital organ has received irreparable damage, which drugs may alleviate but cannot cure.

Anaesthetics and Hypnotics.

Important progress has, how ever, been made in the discovery of drugs needed to produce cer tain temporary alterations in the functions of the body. General anaesthetics are perhaps the most important group of drugs of this class. In 1924 and 1925 acetylene and ethylene were tried as substitutes for nitrous oxide, but at present it is doubtful whether the new gases will prove superior to nitrous oxide.

Many drugs produce some very useful action but have in addi tion some highly undesirable side action. Cocaine (q.v.), for example, is an excellent local anaesthetic, with the grave dis advantage of sometimes producing dangerous effects on the brain. Of the large number of local anaesthetics, which have been syn thesised in the hope of producing some complete substitute for cocaine, Novocaine is one of the best known and can replace cocaine completely for many but not for all purposes. Since 1910 a number of new compounds of great potency as local anaesthetics have been discovered, and cocaine may soon be superseded.