The physiologist who succeeds in penetrating deeper and deeper into the digestive canal becomes convinced that it consists of a number of chemical laboratories equipped with various mechanical devices.
Perfect as the wing of a bird may be, it will never enable the bird to fly if unsupported by the air. Facts are the air of science. Without them a man of science can never rise.
Our success was mainly due to the fact that we stimulated the nerves of animals that easily stood on their own feet and were not subjected to any painful stimulus either during or immediately before stimulation of their nerves.
Our experiments not only proved the existence of a nervous apparatus in the above-mentioned glands, but also disclosed some facts clearly showing the participation of these nerves in normal activity.
Only by observing this condition would the results of our work be regarded as fully conclusive and as having elucidated the normal course of the phenomena.
