584 THE AMERICAN JOURNAL OF SOCIOLOGY
As examples of the utilization of subsequent methods by the antecedent sciences we may cite :
First, the application of the historical method to sciences other than the social sciences, and the utility of this application from the point of view of the progress of inventions.
Second, the physical experiment of Plateau upon the forma- tion of nebulae. By means of a tube, a drop of oil was intro- duced into the center of a mixture of water and alcohol contained in a vase. Through the axis of this drop there was passed a spindle, which was given a regular rotary movement. The sphere of oil turned with its axis. It became flattened at the poles and expanded at the equator. From this enlargement there became detached a sort of ring which broke into globules, each of which began to turn around the central mass.
As examples of the utilization of antecedent methods by the subsequent sciences we may cite :
First, the application of the experimental method to physi- ology and biology.
Second, the application of this same method to sociology, for example, in the private and collective experiments made con- cerning the influence of a reduction of the hours of work upon productivity.
The retrospective view which we have just taken of the struc- ture and evolution of the social theories and methods which have united in the formation of sociology permits us to observe that it is the simplest and most general sciences with their appro- priate methods, consequently the sciences first perfected (the mathematical sciences, mechanics, astronomy), which imparted the first forms and the original direction to sociology. Later, and successively, social conceptions have been under the influ- ence of the physico-chemical sciences, especially in theories of the natural order of societies and of liberal economy. Still later they received the impress of biology; and finally, toward the end of the nineteenth century, and also at the present time, they have been influenced by psycho-physiology.
This subjective evolution and this subjective organization of our social knowledge are parallel with the objective formation
