ALKALOIDS. — The alkaloids are or ganic basic substances, the active prin ciples of most poisonous plants. They are termed "alkaloid" owing to their be havior with acids, which simulates that of alkaline substances: ammonia, etc. Combining with acids they form salts which are convenient, owing to the smallness of their doses and their com parative precision as to the effects to be produced.
Dose and Properties.—A point of im portance in prescribing alkaloids, when they are administered in tablet form, is to avoid too rapid drying of the tablets, the preparation otherwise becoming de teriorated.
Case showing that certain alkaloids are so delicate that they are injured if the tablets are dried too quickly. A prescription of his, calling for a tablet of hyoscyine, morphine, and atropine, was dried in a half-hour instead of a day and a half, as recommended to him by druggists. J. A. Cutter (Medical Bul letin, June, '90).
The following alkaloids are official in the rnited States Pharmacopoeia, but many others are employed that will be considered under their appropriate head Apomorphine hydrochlorate, dose, to grain.
Atropine, dose, to grain. Atropine sulphate, dose,/ 200 to grain.
Caffeine, dose, 2 to 10 grains.
Caffeine citrate, dose, 2 to 5 grains. Caffeine effervescent citrate, dose, 1 to 3 drachms.
Chinoidine, dose, 3 to 30 grains. Cinchonicline sulphate, dose, 5 to 40 grains.
Cinchonine, dose, 5 to 30 grains. Cinchonine sulphate, dose, 5 to 30 grains.
Cocaine hydrochlorate, dose, to 2 grains.
Codeine, dose, to 2 grains. Hydrastine hydrochlorate, dose, grain.
Hyoscine hydrobromate, dose, to grain.
Hyoscyamine hydrobromate, dose, to grain.
Hyoscyamine sulphate, dose, to grain.
Morphine, dose, to grain. Morphine acetate, dose, to grain.
Morphine hydrochlorate, dose, to grain.
Morphine sulphate, dose, to V, grain.
Physostigmine salicylate, dose, to grain.
Physostigmine sulphate, dose, to grain.
Pilocarpine hydrochlorate, dose,/ 12 to grain.
Piperine, dose, to 10 grains. Quinidine sulphate, dose, 5 to 30 grains.
Quinine, dose, 1 grain to 1 drachm. Quinine bisulphate, dose, 1 to 15 grains.
Quinine hydrobromate, dose, 1 to 20 grains.
Quinine hydrochlorate, dose, 1 to 15 grains.
Quinine sulphate, dose. 1 grain to 1 drachm. • Quinine valerianate, dose, 1 to 20 grains.
Sparteine sulphate, dose, 7, to 1 grain.
Strychnine, dose, to grain. Strychnine sulphate, dose, to grain.
Veratrine, dose, 1/so to 1/30 grain.
Physiological Action.—Alkaloids have various degrees of physiological activity when introduced into the animal body. Many are slow in their action, and a large dose is required to produce any observable effect, while others act more rapidly, and arc so potent that even a minute dose may destroy life. Compare, for example, narcotise, one of the al kaloids of opium, with nicotine, the alka loid of tobacco. Twenty to 30 grains of the former have been taken by the human subject without producing any marked symptoms, while the twentieth part of a grain of the latter may induce symptoms so severe as to threaten death.
It is also well known that alkaloids may have a different kind of action on different animals. Thus, grain of atropine will produce serious symptoms of a complex character in a dog, while 3 or even 4 grains may be given to a rabbit without causing any more marked effect than dilatation of the pupil. In considering the physiological actions of those substances, the following general ization may, in the present state of science, be made tentatively: 1. As a general rule, the more complex the or ganic molecule, and the greater the sum of its atomic weight, the more intense will be the action of the substance. 2. Substances that split up quickly into simpler bodies produce rapid. but tran sient, physiological effects, whereas sub stances which resist decomposition in the blood or tissues may produce no appreciable results for a time, but, when they do begin to break up, the effects are sudden and violent, and usually last for a considerable time. 3. Alkaloids have frequently a double action on different parts of a great, physiological system; and their action in a particular group of animals will depend on the relative de gree of development of the parts of the system in that group. Thus most of the alkaloids of opium have such a double action: a convulsive action resembling that of strychnine, due to their influence on the spinal cord or on the motor cen tres in the brain; and a narcotic, or soporific, action resembling that of anaes thetics, due to their influence on sensory centres in the brain. Hence, in animals, where the spinal system predominates, as in frogs, these alkaloids act as convul sants; while in the higher mammals their principal action is apparently on the encephalic centres, which have now become largely developed. (J. G. Me Kendrick.) Besides the individual physiological properties of alkaloids (these will be described under their respective head ings), a few possess a property in coin mon: that of reducing temperature when applied to the surface. This question was studied by Guinard and Geley, of Lyons. Of eighteen substances tried by the authors in solution or as ointments applied on the inner part of the thighs, four were found to possess a constant regulating effect upon thermic reaction. These were cocaine, solanine, sparteine, and helleborine. In cases of true hyper pyrexia a lowering of from 0.9° to 5.-1° F. was produced, the average fall being from 1.8° to 2.7° F., the effect varying according to the patient, and especially according to the disease. They produced a more marked change at the beginning and end of acute affections than in the middle of the attack, and in mild rather than in grave forms. In healthy sub jects the effects were less apparent. It may be hoped to influence the tempera ture in this manner without administer ing the remedy internally.