Chrism, chrism oil, chrismatory. Chrism, literally, is the gift of the Holy Spirit. It can be understood as the mystical power handed down by the church from Christ to the present day. It is what makes ordination of priests by bishops valid, since the bishops, themselves ordained by other bishops, can trace this line back to the original apostles. It is conferred on lay people at Confirmation.
One of the ways in which this power is contained for use by the church is in the form of holy oils, called chrism oils. In the Catholic Church, these are used at baptism, confirmation and in the sacrament of the sick (formerly called last rites). These holy oils are stored either in the sacristy or the aumbry, and taken out and used by the priest as needed.
The Anglican church completely rejected the use of chrism oils at the Reformation, but it was reintroduced in many places in the late 19th century under the influence of the Oxford Movement. Considered rather militant, it gradually fell into disuse; but a growing interest in the healing mission of the church in the last 20 years has seen its use increasing again.
On the some medieval seven sacrament fonts the chrism oils can be seen conveyed in a Chrismatory, a box with a hole for each kind of oil. On other fonts, the chrism oil is held in a deacon's hand. The chrism cloth, a white garment used in baptism, is shown on other fonts. Infants who died before their mother had been 'churched' are sometimes shown wrapped in this cloth on a brass or ledger stone.