Literature: 'Why' at the beginning of sentences [duplicate]

"Why" in this case is not being used as a question word, but as an interjection, such as:

• "Oh! It tastes just like chicken!"
• "Why, it tastes just like chicken!"

It's a old usage, dating back centuries, and it is not obsolete.

It usually indicates a degree of mild surprise in the speaker in response to a remark or a question. I recall a scene in an old movie starring Edward G. Robinson, in which Robinson portrayed a newspaper reporter. He was interviewing a rather rough individual, and when this person saw that Robinson's character was scribbling what looked like incomprehensible gibberish, asked "What the hell is that?" Whereupon Robinson responded in mild surprise: "Why, that's shorthand!"