It is, however, a truism to state that initiation is essential for group differentiation; excluding, of course, the case where membership in a group is not synonymous with birth. When Schurtz, therefore, reconstructs the evolution of initiation, and connects the initiation into a society with that at puberty, he must have been guided by some more fundamental facts than that of the presence of initiation. The postulation of a genetic relationship between the two initiations lay really in the fact that he detected in the form of initiation into the society certain “symptoms” which he regarded as being primarily associated with puberty initiation. These symptoms were the presence of “tests” as essential for admission into a society; and group-initiation or the initiation of a number of youths at the same time. That he was thinking of tests in the most general way, can be seen by the following statement. “Das Austeilen von Schlägen ... im Duk-Duk hängt wohl mit den Mutproben der Knabenweihe zusammen.”[29] It is hardly necessary to insist that the test concept used in this generalized manner is found associated with the ordinary forms of eligibility; so that, wherever the idea of eligibility is associated with a social or ceremonial group, there it will be natural to find tests. There is no need of giving any examples: they must occur to every one. The test feature must consequently be considered so general a cultural possession that its association with diverse cultural phenomena is quite natural, and its significance will in each case depend upon specific conditions. We cannot, therefore, predicate any general significance for the association of the test feature in specific cultural complexes. Schurtz’s second symptom comes out strongly in his discussion of the Ruk-Ruk Society of Northern Bougainville.[30] We have here, he says, a remarkable connecting link between simple men’s associations (_Männerbünde_), firmly established by puberty rites and secret societies. He arrives at this conclusion, because he finds it customary there to have a group of youths initiated into the society at the same time. Here both the youth of the novices and the group initiation are emphasized as being symptomatic of a development from former men’s associations (_Männerbünde_).