I'm in the UK, signed into Google, and I can't read it. It says "no preview available". :S
If our level of understanding of psychology hasn't increased since 1909, then the date of the book is irrelevant, of course. However, I was led to believe that massive advances in psychology took place in the 1920s an 30s, and still do today. Thus I'd contend that using that book to explain a psychological position is like using Charles Darwin's "Origin of Species" to explain modern developmental evolution.
If our level of understanding of psychology hasn't increased since 1909, then the date of the book is irrelevant, of course. However, I was led to believe that massive advances in psychology took place in the 1920s an 30s, and still do today. Thus I'd contend that using that book to explain a psychological position is like using Charles Darwin's "Origin of Species" to explain modern developmental evolution.