 As the Tenth Doctor he repeats this assertion, adding also that he is somehow innately able to sense which events in time are 'fixed' and which are in 'flux'.<ref></ref> The Eleventh Doctor slightly amends what was said earlier in "The Doctor's Wife", saying that he could only sense if there were other Time Lords in this universe.In the original series episode "Warriors' Gate", Romana is called a 'time-sensitive' by a marauding slaver and, though she seems to deny this, is able to interface with his spaceship in ways that only a 'time-sensitive' is supposed to be able to.<ref name="warriors"></ref> In "Utopia", the Tenth Doctor states that he finds it difficult to look at Captain Jack Harkness because Jack's existence has become fixed in time and space.In the Series 4 episode "Journey's End", the Tenth Doctor was shown to use his telepathic abilities to wipe Donna Noble's mind of certain memories, specifically the memories of her travels in the TARDIS and to 'implant' a defence mechanism which is activated in "The End of Time".