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Are, according to some, all those in the life of man, which are multiples of the number 7, Septen'niads. Others have applied the term to years, resulting from the multiplication of 7 by an odd number. Some have admitted only three climacterics; others, again, have extended them to multiples of 9. Most, however, have considered the 63d year as the Grand Climacteric ;-63 being the product of the multiplication of 7 by 9, and all have thought that the period of three, seven, or nine, which they respectively adopted, was necessary to the entire renewal of the body; so that there was, at these times, in the economy, none of the parts of which it had previously consisted. The climacteric years have also been called, (Anni) hebdomad'ici, scala'res, grada'rii, scan'siles, genethliaci, natalit"ii, fata'les, crit'ici, decreto'rii, hero'ici, &c. All the notions on the subject are essentially allied to the doctrine of numbers of Pythagoras.