Many of the brethren chew tobacco, and I have advised them to be modest about it.  Do not take out oa whole plug of tobacco in meeting before the eyes of the congregation, and cut off a long slice and put it in your mouth, to the annoyance of everybody around.  Do not glory in this disgraceful practice.  If you must use tobacco, put a small portion in your mouth when no person sees you, and be careful that no one sees you chew it.  I do not charge you with sin.  you have the "Word of Wisdom."  Read it.  Some say, "Oh, as I do in private, so I do in public, and I am not ashamed of it."  It is, at least, disgraceful....Some men will go into a clean and beautifully-furnished parlour with tobacco in their mouths, and feel, "I ask no odds."  I would advise such men to be more modest, and not spit upon the carpets and furniture, but step to the door, and be careful not to let any person see you spit; or, what is better, omit chewing until you have an opportunity to do so without offending....We request all addicted to this paractice, to omit it while in their houses [the tabernacle].  Elders of Israel, if you must chew tobacco, omit it while in meeting, and when you leave, you can take a double portion, if you wish to.

-Brigham Young (sermon, Mar. 10, 1861 in Journal of Discourses 8:361-362; sermon of May 5th, 1870, Deseret News Weekly, May 11, 1870)

-Leonard J. Arrington, Adventures of a Church Historian (pg. 58)