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 plant life 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.