The John Collins is a Cocktail which consists of Genever, Fresh Lemon Juice, Sugar, and Sodawater. Made in the same way as a Tom Collins. However, "Vintage Cocktails" by Susan Waggoner and Robert Markel (1999) describe a John Collins as being made with bourbon.
"A DISCUSSION OF DRINKS", New York Times (Jul 15, 1883)
"THE STEWARD'S HANDBOOK AND GUIDE", by Jessup Whitehead (1893)
Pp. 304-307- John Collins