What I plan to report here grew out of our joint experimental work and represents a certain, not yet completed, attempt to theoretically interpret what was determined in quite a number of investigations. [1] The main goal of these investigations was to draw together two lines of investigation—the genetic and the pathological one. Thus, this attempt (not formally, but according to its essence) can be regarded as an attempt to point out the new problems that emerge here. These emerge because we now compare a number of psychological problems which have thus far been investigated in the plane of the development of functions with the same problems stated in the plane of the loss of these functions and select what may have practical value for the investigations of our laboratory.