Most works on mind in the lower animals are large and ponderous volumes, replete with technicalities, and unfit for the general reader; therefore the author of this book has endeavored to present the evidences of mental action, in creatures lower than man, in a clear, simple, and brief form. He has avoided all technicalities, and has used the utmost brevity consistent with clearness and accuracy. He also believes that metaphysics has no place in a discussion of psychology, and has carefully refrained from using this once powerful weapon of psychologists.
eyes." These eyes are supplied with nerves, one of whose functions is volitional, as I will endeavor to show in my chapter on Conscious Determination.
The manubrium, or handle, is also the centre of a nerve-system. Nerves proceed from it and are spread out on the inner surface of the bell. These nerves preside over digestion, and are involuntary. Certain ganglia in the manubrium appear to preside over volitional effort. I have never been able, however, to locate their exact position, nor to determine their precise action. They will be discussed more fully in the next chapter.
The nervous system of the nectocalyx is exceedingly sensitive, responding with remarkable quickness to stimulation. When two or three minims of alcohol are dropped into a pint of water in which one of these creatures is swimming, the pulsing of the nectocalyx is notably increased in frequency and volume.
Romanes determined that the centres governing pulsation were located in the nerve-ring of the swimming-bell, and t