Joseph Collins had a novel reaction to “Blood on the Street: The Sensational Inside Story of How Wall Street Analysts Duped a Generation of Investors.” The 2005 book by Charles Gasparino, now of Fox Business News, inspired Collins to create a potentially revolutionary Internet communications tool. “I was reading Charlie’s book and I thought it was very unfair that Eliot Spitzer could just walk into companies and demand their email,” Collins recalled. Spitzer was New York’s Attorney General when the Internet busted, and he exposed a steady stream of embarrassing emails from Wall Street cheats. Some of the most memorable were from Merrill Lynch’s former star Internet analyst Henry Blodget calling a company he was publicly hyping “a pos.” That stood for “piece of” something I can’t even spell in this column. What the world really needed, Collins decided after reading Gasparino’s book, were emails that couldn’t be copied, forwarded or saved. That way, people could speak candidly without worrying about overreaching snoops like Spitzer.Collins, 32, a Northwestern University graduate, was struggling to build a chain of gas stations amid rising real estate and gasoline prices. He saw a brighter future in designing disappearing emails. The result is VaporStream electronic conversation software, which is available on a free-trial basis at www.vaporstream.com. “It’s just a new form of instant messaging or email,” Collins said. “We like to think of it as the natural evolution of online communications.”