Uncle Jack Finch is Atticus’ younger brother, therefore also Scout and Jem’s uncle.  His real name is John Hale Finch.  The Finch children mainly see him around Christmas, when their family gets together in Maycomb Junction.  He is a doctor, he has a cat named Rose Aylmer, and he smells sweet, according to Scout.  He also is around Miss Maudie’s age and they have known each other for a while, so they like to tease each other.  Uncle Jack gets the Finch children air rifles one Christmas, to Scout and Jem’s delight.  Uncle Jack also reprimands Scout when he hears her swearing.  He breaks up a fight between Cousin Francis and Scout, but only listens to Cousin Francis’ side.  Later, Scout has the chance to explain to him that Francis provoked her because he called Atticus a “Negro-lover”.  Uncle Jack tells Atticus that he learned his first lessons about children that day.