Whatever I had preached to prove my point and forward my ambition, in truth I had never doubted the efficacy of vaccination, although I was well aware of the dangers that might result from the use of impure or contaminated lymph, foul surroundings, and occasionally, perhaps, certain conditions of health in the subject himself.

Therefore I had no prejudice to overcome, and certainly I was not a Conscientious Objector.
It came to this then.

There were only two reasons why I should not immediately vaccinate myself--first, that I might enjoy in secret a virtuous sense of consistency, which, in the case of a person who had proved himself so remarkably inconsistent in this very matter, would be a mere indulgence of foolish pride; and secondly, because if I did I might be found out.

This indeed would be a catastrophe too terrible to think of, but it was not in fact a risk that need be taken into account.
But where was the use of weighing all these pros and cons?
Such foolish doubts and idle arguments melted into nothingness before the presence of the spectre that stood upon my threshold, the hideous, spotted Pestilence who had slain my father, who held my daughter by the throat, and who threatened to grip me with his frightful fingers.

What were inconsistencies and risks to me compared to my living terror of the Thing that had dominated my whole existence, reappearing at its every crisis, and by some strange fate even when it was far from me, throwing its spell over my mind and fortunes till, because of it, I turned my skill and knowledge to the propagation of a lie, so mischievous in its results that had the world known me as I was it would have done wisely to deal by me as it deals with a dangerous lunatic?
I would do it and at once.
First, although it was unnecessary as all the servants had gone to rest, I locked that door of my study which opened into the hall.