The suggestion I venture to make here is that if we take a comprehensive view of certain two great groups of phenomena in nature, which may be termed universal in their extent, it is difficult to conceive that they are not causally connected in the sense that one is the universal antecedent of the other. On the one hand are found universal minute differences, not only between any pair of organisms, but of any two corresponding parts of any organism, even to the size and shape of each leaf on each plant. On the other is universal discontinuity of _total experience_ of all organisms. This term includes all the stimuli of use and environment to which an organism is exposed throughout its whole existence, and its response to them. It includes the whole succession of active and passive stimuli which begin with the formation of a zygote in higher forms, for example, and continue till the death or end of reproductive life of the individual. It stands for such stimuli as arise from _habitat_ on or in the earth, in various levels of salt or fresh water, in sea, lake, pool and river, and in the branches of trees, from _climate_, from degrees of _light_, _temperature_, _moisture_ and _wind_, from presence and activity of _enemies_ and _rivals_, from _supplies of food_, from _geographical_ and _topographical_ position. Such an enumeration of stimuli might be much extended if it would serve any purpose. But it is enough to say that the number of such stimuli, and the varying degrees in which these are received and responded to, have hardly any limit which we can conceive. It is a very different and harder task to find out the proportion in which such stimuli are advantageous, injurious or indifferent to the organisms, but it may be taken as certain that the vast majority are indifferent in the sense of producing structural change, and, that the advantageous stimuli transmit structural effects to offspring, is only a matter of very strong probability. If the above two groups of phenomena are not causally connected they are intertwined with remarkable closeness and perversity. This aspect of the “web of life” has received attention, and deserves more. Discontinuous Environments.