It is unnecessary to go into details regarding the effects of ablation of the testes. The changes in the hair and skin, the loss of subcutaneous fat, the alteration of the voice, and the mental peculiarities which develop in time are so well understood that further details are unnecessary. In the present state of our knowledge there can be little doubt that the effects of removal of the testes could be obviated by the persistent administration of a normal testicular extract. There is therefore contained in the testes a leucomaine, or organic principle, of great importance in the growth and development of the body.

The testicular extract now employed is obtained from the testes of the bull. These bodies are carefully selected, cut up into small particles, macerated in glycerin with the addition of salt solution, filtered, and sterilized in a suitable apparatus in which it is exposed to the action of liquid carbonic acid. The liquefied carbonic acid is made use of because it is a strong antiseptic and does not impair the virtues of the albuminoids and soluble ferments. This is the method of D'Arson-val, as carried out under Brown-Séquard's direction. Other modes of preparing the extract are followed, but it must be aseptic, and free from all foreign substances. The dose ranges from τη xv to 3 j, injected subcutaneously.

The composition of testicular fluid is complex. Some of its constituents are to be found in the body generally; some are peculiar to these glands. A crystalline principle, a phosphate called spermine, which is contained in it, is held by Poehl to be the active material; but this is not generally admitted. Whatever physiological action the testicular fluid has is due to the albuminoid matters, the leucomaines, and the nucleins which it contains. Brown-Séquard showed in a series of experiments on animals that the fluid increases the power while it lessens the reflex excitability of the nerve-centers. It does not modify the circulation or respiration, but it notably increases the power of the heart when greatly enfeebled by loss of blood. Ataxic symptoms, and paralysis of muscles artificially induced in animals, were made to disappear quickly under its influence. As regards the function of haematosis and the general nutrition, it exercises but little influence.

As the first experiences with testicular extract were in respect to its influence over senility, the condition of senile debility was the first malady in which it was employed therapeutically. Cases are reported by Brown-Séquard, Vogt, Villeneuve, J. J. Putnam, and Loomis, in which the physical and mental decline of age were notably improved. Of a group of 39 cases of senile debility reported by Brown-Séquard and D'Arsonval only 4 or 5 cases were unimproved. Villeneuve says that the fluid revives the organic energies, rejuvenates the faculties, and so improves the mind that mental activity long dormant becomes possible again. It seems certain that decline in the sexual vigor, when purely functional, is one of the conditions improved, even cured, by this remedy. There is by no means unanimity on this, the least questionable point regarding the utility of the testicular fluid. Thus Für-bringer, in his trials of the various extracts, finds them devoid of therapeutical activity. In a discussion recently before the Berlin Medical Society it seemed to be the consensus of opinion that the animal extracts, including the testicular, were of little or no value, except the thyroid.