1836 The Mirror of Literature https://books.google.com/books?id=amBEAQAAMAAJ&pg=RA1-PA21&d...
1841 Proceedings of the Royal Society of Edinburgh https://books.google.com/books?id=tC4_AQAAMAAJ&pg=PA449&dq=%...
1874 Popular Science https://books.google.com/books?id=_B8DAAAAMBAJ&pg=PA347&dq=l...
1877 Popular Science https://books.google.com/books?id=gisDAAAAMBAJ&pg=PA404&dq=p...
1947 Life Magazine https://books.google.com/books?id=bkgEAAAAMBAJ&pg=PA81&dq=%2...
1952 Boys Life https://books.google.com/books?id=QXO4WXYxnAwC&pg=PA50&dq=%2...
1953 Natural Religion and Christian Theology https://books.google.com/books?id=j0yEUu8A5hEC&pg=PA116&dq=l...
1953 Boys' Life https://books.google.com/books?id=z-p67xyiQpQC&pg=PA4&dq=%22...
Where "some reason" is because TV told us so. I wonder where the original myth came from. Obviously the population fluctuation gave rise to it - but someone decided they were committing mass suicide. I'd love to know how much of a "fact" it was before the Disney piece.
http://www.snopes.com/disney/films/lemmings.asp