But if these personages represent, as they certainly do, the spirit of vegetation in spring, the question arises, Why kill them? What is the object of slaying the spirit of vegetation at any time and above all in spring, when his services are most wanted? The only answer to this question seems to be given in the explanation already proposed of the custom of killing the divine king or priest. The divine life, incarnate in a material and mortal body, is liable to be tainted and corrupted by the weakness of the frail medium in which it is for a time enshrined; and if it is to be saved from the increasing enfeeblement which it must necessarily share with its human incarnation as he advances in years, it must be detached from him before, or at least as soon as, he exhibits signs of decay, in order to be transferred to a vigorous successor. This is done by killing the old representative of the god and conveying the divine spirit from him to a new incarnation. The killing of the god, that is, of his human incarnation, is, therefore, only a necessary step to his revival or resurrection in a better form. Far from being an extinction of the divine spirit, it is only the beginning of a purer and stronger manifestation of it. If this explanation holds good of the custom of killing divine kings and priests in general, it is still more obviously applicable to the custom of annually killing the representative of the tree-spirit or spirit of vegetation in spring. For the decay of vegetation in winter is readily interpreted by primitive man as an enfeeblement of the spirit of vegetation; the spirit has (he thinks) grown old and weak and must therefore be renovated by being slain and brought to life in a younger and fresher form. Thus the killing of the representative of the tree-spirit in spring is regarded as a means to promote and quicken the growth of vegetation. For the killing of the tree-spirit is associated always (we must suppose) implicitly, and sometimes explicitly also, with a revival or resurrection of him in a more youthful and vigorous form. Thus in the Saxon and Thüringen custom, after the Wild Man has been shot he is brought to life again by a doctor;(824) and in the Wurmlingen ceremony there figures a Dr. Iron-Beard, who probably once played a similar part; certainly in another spring ceremony (to be described presently) Dr. Iron-Beard pretends to restore a dead man to life. But of this revival or resurrection of the god we shall have more to say anon.