Mystici Corporis Christi §55

⁵⁵ But in virtue of that higher, interior, and wholly sublime communication, with which We dealt when We described the manner in which the Head influences the members, Christ our Lord wills the Church to live His own supernatural life, and by His divine power permeates His whole Body and nourishes and sustains each of the members according to the place which they occupy in the body, in the same way as the vine nourishes and makes fruitful the branches which are joined to it.