One of the phenomena which had peculiarly attracted my attention was the structure of the human frame, and, indeed, any animal endued with life.

Whence, I often asked myself, did the principle of life proceed?

It was a bold question, and one which has ever been considered as a mystery; yet with how many things are we upon the brink of becoming acquainted, if cowardice or carelessness did not restrain our inquiries.

Frankenstein, M. W. Shelley