ELECTRICAL CONDUCTIVITY, ELECTRICAL POTENTIAL AND HYDROGEN ION CONCENTRATION MEASUREMENTS ON THE SUBMAXILLARY GLAND OF THE DOG RECORDED WITH CONTINUOUS PHOTOGRAPHIC METHODS

Abstract

Electrical resistance, electrical deflections and acidity of the venous blood of the sub-maxillary gland of the dog were photographically recorded. In marked contrast to the variability of the electrical deflections obtained under less stringent conditions was the uniformity of the changes in electrical resistance. When visible secretion was elicited an increase in electrical resistance invariably occurred. The difference in behavior of the gland in these respects is probably accounted for by the fact that the electrical deflection is an algebraic sum of the potential differences of individual cells, whereas the net resistance is the arithmetic sum of the resistances of the cells. It is suggested that the changes in resistance may be accounted for by a constancy or decrease in resistance of the lumen side of the cell and an increase in resistance of the opposite side. Stimulation of the cervical sympa thetic fibers caused a smaller and less rapid increase in resistance than stimulation of the chorda tympani or injection of pilocarpin. With the duct occluded during stimulation of the chorda tympani the resistance increase was greater than normal, but subsequently fell below its pre-stimulation value. Retarded blood supply during stimulation likewise elicited a greater increase in resistance followed by a slower return to normal. Secretory activity of the gland was accompanied by increased acidity of the venous blood. Secretion with the duct occluded or with decreased blood supply caused greater than normal increase in blood acidity. Increased acidity of the blood produced by mechanical asphyxia resulted in decreased resistance of the gland.