Quote 19
Who shall conceive the horrors of my secret toil as I dabbled among the unhallowed damps of the grave or tortured the living animal to animate the lifeless clay? (4.9)
Victor’s obsessive drive to create life forces him into secret "horrors."
Quote 20
I saw plainly that he was surprised, but he never attempted to draw my secret from me; and although I loved him with a mixture of affection and reverence that knew no bounds, yet I could never persuade myself to confide in him that event which was so often present to my recollection, but which I feared the detail to another would only impress more deeply. (6.12)
Victor feels disconnected from Henry because he is keeping his knowledge as well as his monster a secret.
Quote 21
My father had often, during my imprisonment, heard me make the same assertion; when I thus accused myself, he sometimes seemed to desire an explanation, and at others he appeared to consider it as the offspring of delirium, and that, during my illness, some idea of this kind had presented itself to my imagination, the remembrance of which I preserved in my convalescence.
The secrecy of Victor’s discovery makes him appear crazy to those around him.