Von Hartmann says: "The explanation that unconscious psychical activity itself appropriately forms and maintains the body has not only nothing to be said against it, but has all possible analogies from the most different departments of physical and animal life in its favor, and appears to be as scientifically certain as is possible in the inferences from effect to cause." Maudsley says: "The connection of mind and body is such that a given state of mind tends to echo itself at once in the body." Carpenter says: "If a psychosis or mental state is produced by a neurosis or material nerve state, as pain by a prick, so also is a neurosis produced by a psychosis. That mental antecedents call forth physical consequents is just as certain as that physical antecedents call forth mental consequents." Tuke says: "Mind, through sensory, motor, vaso-motor and trophic nerves, causes changes in sensation, muscular contraction, nutrition and secretion.... If the brain is an outgrowth from a body corpuscle and is in immediate relation with the structures and tissues that preceded it, then, though these continue to have their own action, the brain must be expected to act upon the muscular tissue, the organic functions and upon the nervous system itself." Von Hartmann also says: "In willing any conscious act, the unconscious will is evoked to institute means to bring about the effect. Thus, if I will a stronger salivary secretion, the conscious willing of this effect excites the unconscious will to institute the necessary means. Mothers are said to be able to provide through the will a more copious secretion, if the sight of the child arouses in them the will to suckle. There are people who perspire voluntarily. I now possess the power of instantaneously reducing the severest hiccoughs to silence by my own will, while it was formerly a source of great inconvenience to me.... An irritation to cough, which has no mechanical cause, may be permanently suppressed by the will. I believe we might possess a far greater voluntary power over our bodily functions if we were only accustomed from childhood to institute experiments and to practice ourselves therein.... We have arrived at the conclusion that every action of the mind on the body, without exception, is only possible by means of an unconscious will; that such an unconscious will can be called forth partly by means of a conscious will, partly also through the conscious idea of the effect, without conscions will, and even in opposition to the conscious will."