Studies on Developing Rats

Recognition of the existence of measurable amounts of electrical currents within the animal body has been widespread ever since the initial experiments upon this form of energy by Galvani" and by Volta.'6' 17, 18 The measurement of action currents was a natural outgrowth of these discoveries. The clinical use of the electrocardiogram brought these phenomena first to the fore and later into the background of thought as the system became a routine of technological exploitation. Vacuum-tube amplifiers have made possible a refined approach to this subject from the biological point of view. Unfortunately, the refinements of method have been emphasized more than have the more significant experimental results. Today the field of electropotential variations is actually limited by the boundaries which must delimit experimental approach in the basic sciences. This blessing is not unmixed, for the application of these methods to fields other than those for which they were invented has led not only to misinterpretations but to the elaboration of unwarranted pseudophilosophical implications. It is not with this ideological compleity that the present study was planned to deal; its province is restricted to the interpretation of physiological manifestation recorded by the changes in electropotential of a specific living organism under specific conditions.