Definition. - The cleaned, dried, and powdered thyroid glands of the sheep, freed from fat.

Description and Properties. - A yellowish amorphous powder, having a slight, peculiar odor; partially soluble in water.

Dose. - Average dose: 4 grains (0.250 Gm. = 250 milligrammes), U. S. P.

Numerous extracts of the thyroid are upon the market, many of them purporting to be the active constituent. Aiodine, opothyroidine, and thyroglandine are other preparations on the market.

Thyreoidectin and rodagen represent a new series of preparations quite recently introduced which must not be confused with the above; their action is stated to be exactly the opposite of that of the thyroid preparations. Thyreoidectin is prepared from the blood, rodagen from the milk, of animals from which the thyroids have been removed.

Numerous chemical studies made during the past few years have seemed to show that the action of the thyroid extract is due to a peculiar body rich in iodine. It is found principally in the colloid substance of the gland, and is rich in globulin, a thyreoglobulin from which a principle, iodothyrin, has been insolated. Although much remains to be learned concerning this iodothyrin, it is safe to assume it as the active principle of the gland. It varies greatly in amount in different glands and at different ages in the human subject.

The most rational and successful application of organotherapy, perhaps, was that of Murray in 1891, who, following Horsley's deductions from Kocher's surgical results, proposed the subcutaneous injection of a thyroid extract in the treatment of myxedema, many cases of which have improved, while others have been definitely cured by the adoption of the remedy. The preparations in this case have included the ingestion of the dry powder, the injection of a glycerin extract, and the raw or partially cooked gland administered as food. The testimony of competent authorities amply attests the efficacy of the agent, which now receives almost universal acceptance. It has, therefore, been made official in the Pharmacopoeia of 1900.

Action. - If injected into the veins of animals, iodothyrin causes an acceleration of the heart action, lowers the blood-pressure, increases the amount of urine excreted, and may give rise to dyspnea and diarrhea. It seems probable that many of the peculiar toxic symptoms that were observed when the older extracts were in use were in reality due to the presence of putrefactive ptomains. In large doses, in man, symptoms somewhat similar to those observed in exophthalmic goiter have been reported. Iodothyrin has also the effect of increasing catabolism and produces a marked breaking-down of proteids, in this way causing loss of flesh. This effect, combined with its diuretic action, renders it valuable in the treatment of obesity.

Therapeutics. - With the treatment of myxedema, cretinism, Basedow's disease, lipomatosis universalis, cachexia strumipriva, and thyroid insanity, it would seem as if the use of thyroid had reached its limitations. The successful administrations and beneficial resultbtained in some of the above diseases, however, have stimulated many observers and experimenters to make a wider trial of this form of medication. Psoriasis has been helped by its use.

The dosage, method of administration, and danger-signals are no less important than the indications for its use. The hypodermic administration of the liquid extract and the grafting of the fresh gland have long fallen into disuse, and the tendency of the present day is to administer the powder or to give tablets or capsules prepared from the desiccated fresh gland. The dose varies with the individual, and for this reason it is advisable to begin with small doses, which should be gradually increased until the desired effect is produced. Beginning with 1 or 2 grains a day, as much as 15 grains may be administered, the prescriber always being on the qui vive for poisonous symptoms. During the course of administration especial attention should be given to the respiratory and cardiac apparatus, and at the first appearance of rapid pulse, embarrassed respiration, rise of temperature, vertigo, or gastric disturbance, its use should be abandoned.

Improvement has been noted in several cases of malignant syphilis, Menzies considering that thyroid acts as a powerful skin-tonic and a useful adjuvant to mercury and potassium iodide in the treatment of this disease.

The favorable results often attending the partial employment of animal agents in diseases of corresponding organs, and especially the noteworthy benefits derived from the application of the thyroid treatment in myxedema, have suggested the preparation of many extracts of varying efficacy.

Parathyroid Gland. - These glands when given in animals are capable of causing muscular tremor and other symptoms. It has been suggested that they may prove of value in treating pathological tremors, particularly paralysis agitans.

Thymus Gland - This organ contains bodies rich in iodine similiar to those found in the thyroid, but as yet no therapeutic application has been followed by marked success.

Pituitary Body. - Inasmuch as acromegaly has been found to be associated very frequently with disease of the pituitary body it has been suggested that this body might be of some service, but thus far success in its use for this disease has been negative. The gland is a complex structure anatomically, and further research may give some results.

Nuclein is a complex proteid body, characterized by its large percentage of phosphorus. The phosporus exists in the form of nucleinic acid; so far as is known, this acid is the same in all cells, yet the basic part differs in various nucleins.

When administered hypodermically or orally, nuclein increases the number of leucocytes in about three hours. The amount of increase varies with the subject; it may be slight or it may be threefold; it occurs principally in the polynuclear cells.

Nuclein is of some value in conditions of infection where the symptoms are due to general invasion of the bacteria. Favorable results are obtained in simple anemias. It is found on the market in a 5 per cent. solution, dose 1 to 2 drams. It should be given on an empty stomach. Vaughan reports that in tuberculosis the effect of moderate injections has been to lower the temperature, without untoward manifestations. Indolent ulcer has yielded completely to a similar treatment.

It is also stated upon high authority that the nucleins are useful in "all forms of anemia, in chronic and recurrent malaria, in digestive disorders, and in acute and chronic pulmonary affections" (Aulde), the nuclein adopted being obtained from the thyroid and thymus glands. The latter author suggests the use of nuclein in the treatment of typhoid, in which disease the activity of leucocy-tosis is defective.

Bile. - This has already been treated.

Bone-marrow has proved efficacious in anemia (Dickson, Frazer), and has also been employed by Filleau in tuberculosis.

Pancreas Extracts. - These have been employed in diabetes, but as yet very crudely and with no effect.

Careful technic is desirable in the use of this class of bodies, and their further study may be crowned with brilliant results.

Suprarenal Glands. - These have already been discussed.