Why The 50-Year Gap In Their History?

DNC: Democratic Party History: "In 1848, the National Convention established the Democratic National Committee, now the longest running political organization in the world. The Convention charged the DNC with the responsibility of promoting 'the Democratic cause' between the conventions and preparing for the next convention.

As the 19th Century came to a close, the American electorate changed more and more rapidly. The Democratic Party embraced the immigrants who flooded into cities and industrial centers, built a political base by bringing them into the American mainstream, and helped create the most powerful economic engine in history. "

This is from the DNC website. Why is there a 50-year gap in their history? You can find the answer at http://moteandbeam.tripod.com and http://mdcurrington.tripod.com/mdc.