Let us see, in the first place, how human beings were supposed to be affected by this mysterious influence under certain circumstances and at particular periods of their existence. As universally in primitive life, the new-born infant must originally have been taboo; for every Roman child needed purification or disinfection, boys on the ninth, girls on the eighth day after birth. This day was called the _dies lustricus_, the day of a purificatory rite; "est lustricus dies," says Macrobius, "_quo infantes lustrantur_ et nomen accipiunt."[30] In historical times the naming of the child was doubtless the more practically important part of the ceremony; though we may note in passing that the mystic value attaching to names, of which there are traces in Roman usage, may have even originally given that part a greater significance than we should naturally attribute to it.[31] Again, when the child reaches the age of puberty, it is all the world over believed to be in a critical or dangerous condition, needing disinfection; of this idea, so far as I know, the later Romans show hardly a trace, but we may suppose that the ceremony of laying aside the _toga_ of childhood, which was accompanied by a sacrifice, was a faint survival of some process of purification.[32] Once more, after a death the whole family had to be purified with particular care from the contagion of the corpse,[33] which was here as everywhere taboo; a cypress bough was stuck over the door of the house of a noble family to give warning to any passing pontifex that he was not to enter it;[34] and those who followed the funeral cortege were purified by being sprinkled with water and by stepping over fire.[35] _Society had effectually protected itself against the miasma in all these cases by the discovery of the means of disinfection._