Page:Popular Science Monthly Volume 26.djvu/763

 spinal cord to the blood-vessels through the ganglia and fibers of the sympathetic system. These nerves, being constantly active, maintain a tonic contraction of the arterial walls.

The medulla is a center for the movements of chewing and swallowing. This center can be excited in a reflex manner, and by the will, but not automatically. There seems to be good evidence that the medulla is a center for combined or co-ordinated movements of the body. Wundt is of opinion that the collective motor-fibers of the body are brought into closer union with each other in this organ. His opinion rests upon the fact that, as long as the medulla is intact, sensible excitations occasion general movements of the body much more easily than when this organ is destroyed.

The question now arises as to the relation between the medulla and consciousness. I do not think we are justified in supposing that consciousness appears in connection with this portion of the nervous system. It is a fact that a frog, having simply the cord and medulla, will react not only in the manner already described, but also by movements of the entire body, away from the scarce of trouble; the animal may even utter a cry as if in pain, yet he may be "merely a non-sentient, non-intelligent reflex mechanism." We know that the medulla is the last portion of the nervous system to come under the influence of anæsthetics. Persons submitting to severe surgical operations frequently cry out violently, and as if in intense pain; yet they assure us afterward that they were not conscious of suffering.

It is common to cite, as Dr. Hammond has done in the article before mentioned, those human beings who are born without a cerebellum or cerebrum, but who perform such actions as breathing, sucking, swallowing, and crying. In these cases the spinal cord and medulla oblongata are well developed. Why consciousness should be ascribed to the activities just named it seems difficult to understand, especially when we consider that similar activities can be produced by a machine constructed for the purpose. To say that, "if these activities are not indicative of the existence of mind, we must deny this force to all human beings on their entrance into the world," is a singular declaration—what would be the harm of such denial?

Most human beings on their entrance into the world have the higher cerebral centers, yet they are so soft and undeveloped as to make it doubtful whether consciousness even then appears; certainly it does not except in most elementary form. We have now to inquire