it is a bogus quote written by nationalists.
the author of this quote, Siem, was born in 1861. he states to have received this in a letter from bismarck himself in 1876 .... writing letters with high profile leaders while being 15 years old?

What is the source of Siem's fabricated quotation? A 1926 book by a notorious anti-Semite, The Secret World Government Or "The Hidden Hand": The Unrevealed in History By Count Cherep-Spiridovich.

You can read this book for free on nationalist websites.

Here is a full article about this bogus quote including sources:
http://www.garynorth.com/public/6940.cfm