A priest was walking along the corridor of the parochial school near the preschool wing when a group of little ones were trotting by on the way to the cafeteria. Little Johnny stopped and looked at him in his clerical clothes and asked, "Why do you dress funny?" 
He told him he was a priest and this is the uniform priests wear. 
Little Johnny pointed to the priest's plastic collar tab and asked, "Do you have an owie?" 

The priest was perplexed till he realized that to him the collar tab looked like a band-aid. So the priest took it out and handed it to Little Johnny, to show him. On the back of the tab were raised letters giving the name of the manufacturer. 

Little Johnny felt the letters, and the priest asked, "Do you know what those words say?" 
"Yes I do," said Little Johnny, who was not old enough to read. Peering intently at the letters he said, "Kills ticks and fleas up to six months!"