The second character of the glandular life, is that of being subject to habitual alternations of increase and diminution. Sleep extends especially to the animal functions; they alone are completely suspended in the ordinary state, and it is this which constitutes sleep. But the glands sleep also to a certain extent, though there is never a complete suspension except in diseases. I would compare the sleep of animal life to the intermissions of intermittent fevers in which the apyrexia is complete, and the sleep of the glands to those of remitting fevers in which the paroxysm is only moderated, though it always continues. The saliva is copiously poured out when aliments enter the mouth, at other times it only moistens this cavity. Whilst the chyme is passing through the duodenum, the pancreas and liver moisten it abundantly; they are also in action during hunger, but in an infinitely less degree. I have convinced myself of this by many experiments upon the comparative state of digestion and hunger; the substance of these experiments I have given elsewhere. We know that it is some time after eating before the kidneys commence their action. The intermissions of the action of the mammæ are almost as real as those of the organs of animal life. Each mucous gland has its time of secretion; it is that in which the surfaces, to which the excretories go, are in contact with any substance that is remaining there, or that is only passing. The glands then must be considered as continually separating a fluid from the blood, and as being at certain periods in greater activity, and consequently as furnishing more fluids. This remission of the glands appears to be owing to a cause nearly analogous to that of sleep, which, in animal life, is produced by the weariness the sensitive and locomotive organs experience, after long continued action. The kind of weariness which the glands are capable of experiencing, is not in general attended with a painful sensation, as in animal life; its nature appears to be wholly different. Yet women, after nursing too long, feel a pain in the breast that warns them to leave off. The testicles become the seat of a painful sensation, when the emission of semen has been many times forced. _Third Character. The Glandular Life is never simultaneously raised in the whole system._