Critical Days

Those which coincide with the formation, by the Moon, directional or transitory, of each successive semi-square or 45° aspect, to its position at birth; or at the commencement of any illness, operation, or event under Horary 
consideration. By noting the positions of the Moon at successive crises, aspects thereto will indicate the prognosis. 
Favorable crises occur at the sextiles of the Moon to its radical place; but the ephemeral aspects it forms while in these 
positions determine the manner in which the crises will pass, and the eventual outcome.

DeVore, Nicholas. Encyclopedia of Astrology. New York: Philosophical Library, 1947.