A curious point may be noticed in the last place. The practical Roman mind seems to have invented a kind of sacrificial insurance, by which a piacular sacrifice might be offered beforehand to atone for any omission in the ritual which was to follow. Thus the Fratres Arvales, if they had to take an iron implement into their sacred grove, offered a piaculum before as well as after this breach of religious rule.[403] Again, the _porca praecidanea_, which I have already mentioned as offered before harvest, was an example of the same system of insurance; for the first cutting of the corn was a sacred rite, and one in which it was easy to take a false step. Writing of this, Gellius says in general terms that _hostiae praecidaneae_ are those which are offered the day before _sacrificia solennia_.[404] The term "piacular sacrifice" (_piaculum_) had a wide range of meaning, apart from the examples here given. With one important form of it I shall deal in the next lecture:[405] others we shall come across later on. NOTES TO LECTURE VIII [340] See Appendix C. [341] Cato, _R.R._ 139, where the language suggests that as the deity was unknown, the _ius_ of the religious act was also uncertain, _i.e._ the ritual was not laid down. De Marchi translates (_La Religione_ _nella vita domestica_, i. 132) "sia a te fatto il debito sacrificio," etc., which sufficiently expresses the anxiety of the situation. Keil reads here "ut tibi ius _est_," and gives no variant in his critical note; but the words just below, "uti id recte factum siet," seem to me to suggest the subjunctive. In any case there is no doubt about _ius._ In _Tab. Iguv._ vi. A. 28 (_Umbrica_, p. 58) Buecheler translates the Umbrian _persei mersei_ by "quicquid ius sit," and compares this passage of Cato, together with Gellius i. 12. 14, where the phrase is used of the duties of a Vestal under the _ius divinum_ in the formula used by the Pontifex Maximus, _cum virginem capiat_: "Sacerdotem Vestalem, quae sacra faciat, quae ius siet sacerdotem Vestalem facere pro pop. Rom." etc. [342] _e.g._ _Aen._ iv. 56, x. 31 ("si sine pace tua atque invito numine," etc.). Cp. _Tab. Iguv._ vi. 30, 33, etc. (_Umbrica_, p. 59), "esto volens propitiusque pace tua arci Fisiae." [343] Livy vi. 41 _ad fin._ [344] Wissowa, _R.K._ p. 318, and p. 319 for the illustrations that follow. Cp. Cicero, _Part. Or._ xxii. 78, where _religio_ is explained as "iustitia erga deos." [345] _Lex Coloniae Genetivae_, cap. 64; _C.I.L._ ii., supplement No. 5439. [346] Livy i. 20. 5.