Diabetes is well established as a disease involving the Islands of Langerhans of the pancreas and it is generally regarded as consisting in the failure of the internal, glycolytic ferment secreted by these portions of the pancreas. Unfortunately there is, as yet, no practical realization of the theoretic treatment by administering such a ferment.

The relative fatness of castrated and spayed animals, of eunuchs and of many women after the natural or artificial establishment of the menopause, suggests that the testicles and ovaries have an internal secretion which controls the oxidation of fat. Extracts of these organs sometimes seem to have a beneficial influence in the rather vague senile changes occurring after the menopause or after the suspension of sexual function in men but their action is uncertain, particularly, in the treatment of obesity.

Extracts of kidney, liver and various other organs have been used empirically in the treatment of corresponding diseases but not with demonstrable benefit that could be distinctly attributed to the extract, and, on the contrary, sometimes with exacerbation of the disease.

The use of hydrochloric acid, pepsin, pancreatic ferments etc., may be mentioned as instances of organotherapy.

Subject to modification by further discoveries, the following general principles may be laid down in regard to organotherapy:

1. Providing an organ has no especial chemic ingredient, its anatomic correspondence to a human organ, gives it no special virtue in the nutrition of the healthy organ or the treatment of the diseased organ. Thus the use of lung to nourish or to heal lung and similar examples, are absurdities.

2. In so far as an organ or secretion contains chemic substances not contained in other parts of the body, or contained in other parts only to a slight degree, its use is logical to provide nourishment for the corresponding organ, or any other that may require the special substance in question. But, if this substance is not a ferment or if, being a ferment, its ferment function is destroyed in the method of preparation, as cooking, or in the course of digestion and absorption or if the substance requires material change by digestion before it can be assimilated, its action is purely nutritive and does not possess any conspicuous advantage over ordinary animal foods. For instance, it is logical to assume that the brain and spinal cord and even nerve trunks and ganglia administered as food or as properly prepared extracts, somewhat facilitate the supply of special reconstructives to these organs. But it is absurd to imagine that they can have any direct therapeutic value in the treatment of diseases of these organs or that they can even materially increase intellectual and nerve function.

3. While chemic processes are included in the activity of all organs, we can distinguish pretty clearly (1) those whose function is mechanic, chemic manifestations being concerned only in the general nutrition and metabolism; (2) those whose function is physical in ridding the body of chemic substances not secreted in the organ itself or in supplying the body with substances not materially changed by the organ itself; (3) those whose function is to effect a decided chemic change in the material brought to them. The muscles, including the heart, and in a more recondite sense of discharging energy, the nervous organs are included in the first category. The dense supporting structures, bones, cartilage, ligaments, connective tissue conform even more closely to this conception of mechanic function.

The kidneys, sweat glands and lungs belong in the second category. The other glands, with or without ducts, perform strictly chemic functions though in some instances, as the liver, both physical excretion and true chemic activity are united.

As a general principle, it may be stated that organs performing purely mechanic and physical functions, cannot be benefited either in health or disease - excepting as mentioned under 2 - by organotherapy. On the contrary, the use of an excreting organ or its extract is, in general directly harmful and especially so when its function is in any way embarrassed. But it must not be overlooked that these organs may possess functions not at present known so that properly prepared extracts, free from toxic waste substances, may ultimately prove of benefit.

4. The mere fact that an organ possesses a true chemic, secreting function is not an assurance that it or its extract will prove of value. To fulfill this condition, there must be some sub-stance, usually a ferment, which performs some definitely useful function, which is not toxic to any decided degree, which can be artificially introduced in efficient and harmless state. The liver, for instance, acts both as a ductless and a duct-discharging gland, bile contains both excreta and secreta, the bile pigments, although toxic excreta, are actually secreted by the liver, that is to say, they do not preexist in the blood but are manufactured by the liver. Obviously, we cannot stimulate the internal secretion of the liver by administering bile - nor by any other "extract" as yet discovered - and we should limit the attempt to supply bile to the use of the taurocholate and glycocholate salts.

5. Animal extracts should be very cautiously employed till it is proved that the condition under treatment is due to a deficiency and not to an excess of the substance in question. For example, exophthalmic goitre though undoubtedly due to thyroid disease, is made worse by the use of thyroid extract, iodothyrin, or even iodin in other form.

6. They should also be employed cautiously until it is determined that as administered, they have no serious deleterious influence. (See discussion of adrenalin.)

7. Even when there is a demonstrable deficiency of a definite secretion, as the digestive ferments, there may be practical contraindications to the use of these substances. For instance, pepsin is very rarely indicated. If the stomach has any secretory activity at all, pepsin is usually present in the form of an undeveloped enzyme which can be perfected by the administration of a sufficient quantity of hydrochloric acid. If there is a genuine achylia, the stomach can be made to secrete by appropriate measures, if the achylia is functional; if the achylia is due to organic change, it is usually better not to attempt an artificial performance of its function but the food should either be predigested or reliance should be placed on pancreatic and intestinal digestion.