Translating to “spirit of life” and taken from its original form “Spiritus Mundi” (spirit of the Universe), Spiritus Vitae refers to the interaction between the cosmic forces and the matter of the human body.
Sam confirms to Dean, that Dean's suspicion that they are dealing with a witch is right. Sam goes on to tell Dean that they are dealing with a shtriga, a kind of Albanian witch, with legends that date back to ancient Rome that feed of off spirtus vitae. Confused as to what spritus vitae is, Sam tells Dean it is Latin and translates to "breath of life" -- a person's life force or essence.
In order to get Sam and Dean to stop performing the trials, Crowley begins killing all the people the Winchesters have saved. While on a blind date with Sheriff Jody Mills as "Roderick," Jody excuses herself to the bathroom. Crowley then goes on to set-up a spell and begins chanting a death spell.
Manu mortis accesso spiritus vitae recedit.