T244 HE WILL IN NATURE.
their being occasioned by stimuli or by motives, i.e. in their having a brain for their medium or not; and the stimulus may again be merely interior or exterior. In several animals of a higher order crustaceans and even fishes he finds that the voluntary and vital movements, for instance locomotion and respiration, entirely coincide: a clear proof that their origin and essence are identical. He says on p. 188: "In the family of the actinia, star fishes, sea-urchins, and holothurice (echinodermata pedata Cuv.), it is evident that the movement of the fluids depends upon the will of the animals and that it is a means of locomotion." Then again on p. 288: "The gullet of mammals has at its upper end the pharynx, which expands and contracts by means of muscles resembling voluntary muscles in their formation, yet which do not obey the will." Here we see how the limits of the move ments proceeding from the will and of those assumed to be foreign to it, merge into one another. Ibid., p. 293: "Thus movements having all the appearance of being voluntary take place in the stomachs of ruminants. They do not however always stand in connection with the ruminating process only. Even the simpler human stomach and that of many animals only allows free passage to what is digestible through its lower orifice, and rejects what is indigestible by vomiting."
There is moreover special evidence that the movements induced by stimuli (involuntary movements) proceed from the will just as well as those occasioned by motives (voluntary movements): for instance, when the same movement follows now upon a stimulus, now again upon a motive, as is the case when the pupil of the eye is contracted. This movement, when caused by in creased light, follows upon a stimulus; whereas, when occasioned by the wish to examine a very small object minutely in close proximity, it follows upon a motive; because
