One of the commonest forms of taboo is that on women, who, especially at certain periods, were apparently believed to be "infectious."[36] Of this belief we have very distinct survivals in Roman ritual, which I must here be content to mention only, leaving details to trained anthropologists to explain. We find them both in _sacra privata_ and _sacra publica_. Cato has preserved the formula for the propitiation of Mars Silvanus in the private rites of the farm; it is to take place _in silva_, and its object is the protection of the cattle, doubtless those which have been turned out to pasture in the forest, and are therefore in danger from evil beasts and evil spirits. Now this _res divina_ may be performed either by a free man or a slave, _but no woman may be present_, nor see what is going on.[37] In _sacra publica_ women were excluded from the cult of Hercules at the Ara Maxima, and were not allowed to swear by the name of that god; facts which are usually connected with the doubtful identification of Hercules with Genius, or the male principle of life.[38] More conclusive evidence of taboo in the case of women is the fact that at certain sacrifices they were ordered to withdraw, both _mulieres_ and _virgines_, together with other persons to be mentioned directly.[39] Unfortunately we are not told what those sacrifices were; but it seems clear enough that there had been at one time a scruple (_religio_) about admitting women of any age to certain sacred rites. If so, it is remarkable how the good sense of the Roman people overcame any serious disabilities which might have been produced by such ideas; the Roman woman gained for herself a position of dignity, and even of authority, in her household, which had very important results on the formation of the character of the people.[40] Traces of the old superstition doubtless continued to survive in folklore; an example, interesting because it seems to illustrate the positive aspect of taboo (_mana_), may be found by the curious in Pliny's _Natural History_, xxviii. 78.