*appetency*

n.; pl. Appetencies [ L. appetentia, fr. appetere to strive after, long for. See Appetite. ] 1. Fixed and strong desire; esp. natural desire; a craving; an eager appetite. [ 1913 Webster ]

They had a strong appetency for reading. Merivale. [ 1913 Webster ]

2. Specifically: An instinctive inclination or propensity in animals to perform certain actions, as in the young to suck, in aquatic fowls to enter into water and to swim; the tendency of an organized body to seek what satisfies the wants of its organism. [ 1913 Webster ]

These lacteals have mouths, and by animal selection or appetency the absorb such part of the fluid as is agreeable to their palate. E. Darwin. [ 1913 Webster ]

3. Natural tendency; affinity; attraction; -- used of inanimate objects. [ 1913 Webster ]