Why Immigrate?

In 1911 my grandfather immigrated to Canada. Records show that he made the trip alone. What made him leave the country of his birth and why was he by himself? The family story was that he saw a poster advertising Canadian immigration in a railway station. Could it really have been a simple as that to leave family and country? Armed with these questions, I uncovered a story that explained so much and shed light on a scourge that devastated so many people that there were few families not affected by it. The scourge was tuberculosis.