Though there were priests appointed to conduct the ceremonies of public worship, they were in no sense intermediaries. Every suppliant addressed himself directly to the divinity. He might consider it to his advantage to consult the professional men, who were skilled in the knowledge of how most persuasively to approach the gods; but the act of intercession was each person's own affair, and did not need the intervention of a proxy. Therefore, the women were as free to address the gods as were the men; and, in fact, in the many matters which concerned their sex particularly, and in other things in which it seemed fitting, they alone could properly do so. Bespeaking the favor of a particular deity consisted in paying that god more or less extra attention; generally it was a very simple process. There is in existence a painting, found at Rome, which represents two women offering incense to Mars, their husbands probably being absent with the army. Each of these matrons has brought a portable altar, and into the rising flames, before a small figure of the deity, they are dropping the fragrant oblation. This sacrifice may have taken place in the open air; probably in the Forum. Thus easy was it for women to pay their devotions and to invoke protection for those in whose welfare they were interested. The practical Romans looked upon their relations to the deities as partaking somewhat of the nature of commerce; for a certain amount of attention they were justified in expecting a corresponding amount of protection. They even practised what might truly be called pious frauds upon the powers whom they worshipped. In certain cases, it seemed to them that, inasmuch as the gods could not make use of the reality, an inexpensive substitute might well take its place. For instance, it is a relief to know that the yearly sacrifice of men which the Vestals made to Father Tiber from the Sublician Bridge had nothing in it more human than representations of men made out of osiers; but when we read of the heads of poppies and even onions being presented to Jupiter, in order that he might practise his thunderbolts upon them, instead of upon the heads of the citizens, the instinct of self-preservation is more apparent than is the reasoning faculty which they attributed to the god. The Romans studied economy in their religion. Their meat offerings constituted the family meal; and a pig seemed to them the more proper object to sacrifice to the gods, in that its flesh was a favorite article of diet with themselves.