"What is a Globular Cluster? What is an Open Cluster?"

Determining the lower mass limit to maintain ejecta from a first generation of stars in a massive cluster in order to form a second generation and therefore display multiple populations is of great interest. I will present high resolution spectral data on 2 clusters that bear on this important topic. I will also discuss how broad-band Washington photometry can be an efficient tool for uncovering multiple populations.