De Opificio Mundi

It also happens that all the changes of the voice amount to seven; the acute, the grave, the contracted, in the fourth place the aspirated sound, the fifth is the tone, the sixth the long, the seventh the short sound.

There are also seven motions; the motion upwards, the motion downwards, that to the right, that to the left, the forward motion, the backward motion, and the rotatory motion, as is most especially shown by those who exhibit dances.

It is affirmed also that the secretions of the body are performed in the aforesaid number of seven. For tears are poured out through the eyes, and the purifications of the head through the nostrils, and through the mouth the saliva which is spit out; there are, besides two other channels for the evacuation of the superfluities of the body, the one being placed in front and the the other behind; the sixth mode of evacuation is the effusion of perspiration over the whole body, and the seventh that most natural exercise of the generative powers.

Again, in the case of women, the flux called the catamenia, is usually carried on for seven days. Also, children in the womb receive life at the end of seven months, so that a very extraordinary thing happens: for children who are born at the end of the seventh month live, while those who are born at the expiration of the eighth month are altogether incapable of surviving.