I. Concerning the influence of polarized light on some convulsant drugs

Abstract

In connection with a study of the effects of light on the actions of various drugs and poisons, which the author has been carrying on during the last few years—a field of science to which the term “photo-pharmacology” may be appropriately applied—the author made some extremely interesting observations on the influence of polarized light on the pharmacological action of certain drugs on animals, which it is the purpose briefly to describe in this communication.

The influence of light on the effects of certain cerebrally acting convulsant drugs in rats was investigated. The drugs studied in particular were camphor, santonin, and cocain. A number of experiments were also made with solutions of carbolic acid. The above drugs were injected either subcutaneously or intraperitoneally in equivalent doses in white rats, and the onset, severity and duration, etc., of the convulsions were noted under different conditions. Equivalent quantities of a drug per body weight were injected simultaneously into two or more rats. One of the animals was exposed to polarized light, while the other was illuminated by a non-polarized light of the same intensity, the temperature and other conditions being the same in the two sets of experiments. The source of light used was electric Mazda lamps of 150 or more kilowatts. Polarized light was obtained in some experiments by means of a large Nicol prism, while in others by the well known physical expedient of allowing rays of light to fall on a pile of glass plates at the proper (“polarizing”) angle. The latter method was the more convenient one for the present investigation.

It was found that after injection of camphor (in the form of camphorated oil, U. S. P.), of santonin (in the form of solutions of sodium santoninate), and of cocain hydrochloride, the convulsions came on much more quickly and were of greater violence in the rats exposed to polarized light, than in those rats which were injected with the same quantities of the same drugs and exposed to non-polarized light.