introducing a new dog

Question
i have an 8 year old yorkshire terrier cross who before i got her had been living with a number of other dogs and cats.   I am rescuing a 2 year old male neutered cocker spaniel and would like to know the best way to introduce them.  My yorkie cross will not be a problem and i have been told the cocker does get on with other dogs and cats but still want to know how to make this an easy transition for us all

Answer
The more mature the Cocker, and the less it treats other dogs like chew toys, the better this is going to go.  Likely, the Yorkie is old enough it will want nothing of the typical puppy play biting from the larger, younger Cocker.  A well socialized male will accept the rebuffs from the female.  She may even go ahead and do some of the play.  Sometimes it can be hard to sort out, often you can recognize the quick short snaps and yelps of ''Leave me alone!''.  If so, correct him.  In general, a male and a female is the combination most likely to get along.  Two of one sex sometimes become to competitive for status.  

I don't know if the recommended meet on neutral ground, and keep them on leash at first helps or not.  It can't hurt, and certainly is worth trying.  I try using the new puppy's name and talking excitedly around Aster the grouch, but I don't think it does too much good.  Aster is 12 and has had to put up with a new puppy each of the last 3 years.  She is not impressed, and wants nothing to do with the sharp little teeth.