these movements of the flesh hinder a man from
receiving this sacrament.

Obj. 4: Further, venial sin is no hindrance to receiving the
sacrament, nor is mortal sin after repentance. But even supposing
that seminal loss arises from some foregoing sin, whether of
intemperance, or of bad thoughts, for the most part such sin is
venial; and if occasionally it be mortal, a man may repent of it by
morning and confess it. Consequently, it seems that he ought not to
be prevented from receiving this sacrament.

Obj. 5: Further, a sin against the Fifth Commandment is greater than
a sin against the Sixth. But if a man dream that he has broken the
Fifth or Seventh or any other Commandment, he is not on that account
debarred from receiving this sacrament. Therefore it seems that much
less should he be debarred through defilement resulting from a dream
against the Sixth Commandment.

_On the contrary,_ It is written (Lev. 15:16): "The man from whom the
seed of copulation goeth out . . . shall be unclean until evening."
But for the unclean there is no approaching to the sacraments.
Therefore, it seems that owing to such defilement of the flesh a man
is debarred from taking this which is the greatest of the sacraments.

_I answer that,_ There are two things to be weighed regarding the
aforesaid movements: one on account of which they necessarily prevent
a man from receiving this sacrament; the other, on account of which
they do so, not of necessity, but from a sense of propriety.

Mortal sin alone necessarily prevents anyone from partaking of this
sacrament: and although these movements during sleep, considered in
themselves, cannot be a mortal sin, nevertheless, owing to their
cause, they [sometimes] have mortal sin connected with them; which
cause, therefore, must be investigated. Sometimes they are due to an
external spiritual cause, viz. the deception of the demons, who can
stir up phantasms, as was stated in the First Part (I, Q. 111, A. 3),
through the apparition of which, these movements occasionally follow.
Sometimes they are due to an internal spiritual cause, such as
previous thoughts. At other times they arise from some internal
corporeal cause, as from abundance or weakness of nature, or even
from surfeit of meat or drink. Now every one of these three causes
can be without sin at all, or else with venial sin, or with mortal
sin. If it be without sin, or with venial sin, it does not
necessarily prevent the receiving of