One who contributes for a poor person, his neighbor or his townsman is exempt [from a kalbon]. But if he lent [the half shekel to] them, he is obligated [to pay a kalbon].  Brothers who are partners, when they are obligated to pay a kalbon they are exempt from the animal tithe; but when they are obligated to give the animal tithe, they are exempt from the kal-bon.  And how much is this kalbon? A silver ma’ah; the words of R’ Meir. But the Sages say: Half [a ma’ah].