There can be no doubt as to the importance of the internal secretions of the three chief ductless glands. What about other organs—the glands which make external secretions, for example? Does each of them make also an internal secretion which influences the activity of other organs? It is very difficult to prove the production of internal secretions by such organs as the salivary glands, the pancreas, the kidneys, because all the effects which result from their removal may be due to the suppression of their external secretions. It is almost impossible to distinguish the consequences which might be due to the abolition of an internal secretion from those which ought to be attributed to the loss to the body of the chief functions of the organ. Certain physiologists are inclined to think that all organs—not only the glands, but the liver, spleen, muscles, etc.—produce chemical messengers which are discharged into the blood; and recent discoveries tend to justify this view. As the time approaches when milk will be wanted for the nourishment of offspring, it begins to appear in the breast. Hitherto this has been attributed to nervous control. It is now known that the secretion is provoked by a chemical messenger. If this messenger, extracted from the organ in which it is formed, be injected into the veins of an animal which has no call to secrete milk, it sets up a condition of activity in its mammary glands. Such an illustration of the possibilities of chemical, as distinguished from nervous, control inclines us to attribute the harmonious working of the body in large measure to the mutual influence of its several parts, instead of invoking in every case, as used to be the custom, the directing power of a somewhat bureaucratic nervous system. It is curious to note that an internal secretion is essentially a drug. Faith in drugs has suffered eclipse in latter days, and with good reason. The medicines of fifty years ago so little resembled Nature’s pharmacy that there is cause enough for astonishment at the credulity of a generation that believed them to be charms by the exhibition of which they could direct the working of the body. To be quite just, our forebears did not exactly adopt this view. They still believed in remedies. Docks grew in the same hedgerow as nettles. Therefore the juice of the dock was an antidote to nettle-stings. Washerwomen found wasps vexatious, but, fortunately, “blue-ball” cured the pain of their stings, and prevented the swelling which otherwise would have occurred.