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    Untitled Article

    We now come to the action of the heart . * In man , and in all warm-blooded animals , the whole blood of the body , in successive streams , is collected and concentrated at the heart . The object of the accumulation of a certain mass of it at this

    organ is to subject it to the action of a strong muscle , and thereby to determine its transmission with adequate force and precision through the different sets of capillary vessels . All the blood in the body is in succession brought to the heart ; the heart is , therefore , the central engine that works the current .

    * But it i 3 different from every other engine with which we are acquainted . It generates the power , it communicates . It accomplishes what no mere mechanism ever has or ever can accomplish . It originates a motive power . * In the best constructed machinery , and in machinery that acts with the most prodigious power , there is no real generation of power . There is merely concentration , merely direction of pre-existing power .

    There are particular applications of it to the accomplishment of specific purposes , but there is no origination of it . But when we pass into the region of life we are in a new world , where , though there is still mechanism , put and kept in play by adjustments the most admirable , there is always something beyond mechanism , something

    not only not mechanical nor physical , but to which neither mechanics nor physics present anything analogous . '— ' And of this the action of the heart affords a beautiful illustration . The heart is a muscle ; its action is muscular action , and its action consists in the exercise of one single property , that of diminishing its length or shortening itself . But what is it that causes the muscle to contract ? Take the case of

    a voluntary muscle . What is it that causes the muscles of my arm to contract , and that thereby enables me to move it ? I apply no force to the muscle ; I make use of no pressure ; I employ nothing analogous to the force , without the previous exercise of which there would be no recoil in the spring ; no expansion in the body compressed . I perform a mental act ; that state of consciousness takes place which is called volition . I have a desire to gratify , a purpose to accomplish—instantly , as soon as the thought is conceived , as if

    by the conception of the thought , the required muscular motion is performed . —Where is the physical force here ? Where the mechanical power ? There is nothing analogous to it . The force that is exerted , the power that is called into exertion , is new power ; it is generated at the moment it is needed ; it passes away the instant it has performed its office ; there is no possibility of accumulating it ; no means of concentrating it ; no mode of perpetuating it . Every act of voluntary motion performed by a voluntary muscle must be preceded by the mental state of volition ; this is necessary , but this is all that is

    necessary . 4 Take , on the other hand , the case of the involuntary muscle . Though the property of contractility resides in the muscle , yet no muscle can contract of itself . It must be excited to contraction by 6 Qme agent exterior to itself ; and that agent , whatever it be , is called p . stimulus . Of a voluntary muscle the appropriate stimulus is volition , or , more correctly speaking , some nervous influence sent from the brain , or spinal cord , into the muscle by the act of volition .

    Untitled Article

    128 Dr . Southwood Smith on the Animal Economy '•

• Citation
  • Monthly Repository (1806-1838) and Unitarian Chronicle (1832-1833), Feb. 2, 1833, page 128, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/mruc/issues/vm2-ncseproduct2608/page/60/