We have seen that the Flamen Dialis was not allowed to walk under a trellised vine.(638) The reason for this prohibition was perhaps as follows. It has been shown that plants are considered as animate beings which bleed when cut, the red juice which exudes from some plants being regarded as the blood of the plant.(639) The juice of the grape is therefore naturally conceived as the blood of the vine.(640) And since, as we have just seen, the soul is often believed to be in the blood, the juice of the grape is regarded as the soul, or as containing the soul, of the vine. This belief is strengthened by the intoxicating effects of wine. For, according to primitive notions, all abnormal mental states, such as intoxication or madness, are caused by the entrance of a spirit into the person; such mental states, in other words, are regarded as forms of possession or inspiration. Wine, therefore, is considered on two distinct grounds as a spirit or containing a spirit; first because, as a red juice, it is identified with the blood of the plant, and second because it intoxicates or inspires. Therefore if the Flamen Dialis had walked under a trellised vine, the spirit of the vine, embodied in the clusters of grapes, would have been immediately over his head and might have touched it, which for a person like him in a state of permanent taboo(641) would have been highly dangerous. This interpretation of the prohibition will be made probable if we can show, first, that wine has been actually viewed by some peoples as blood and intoxication as inspiration produced by drinking the blood; and, second, that it is often considered dangerous, especially for tabooed persons, to have either blood or a living person over their heads.