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sure, which would be thus induced, is counteracted by greater rapidity of the heart, and constriction of the vessels in other regions. Thus dilatation of the abdominal vessels during the act of digestion is accompanied by the proverbial coldness of the skin, and the constricted vessels and cold feet of active brain work are familiar to us all. These instances of the obviously protective action of the cardiac and vascular reflexes might be multiplied indefinitely, but there are many others the significance of which is not so apparent. Among these may be mentioned the reflex inhibition of the heart, which is so easily excited by irritation of the air passages[1] and lungs.[2] There is little reason to doubt, however, that like the similar inhibition of the respiration from irritation of the interior of the heart,[3] they play an important part in the mutual regulation of the intimately interdependent functions of the circulation and respiration. The cardiac, vaso-motor, and respiratory
