Story wise, this piece belongs to Tibbs. He finds the pups and becomes Jasper's target. Jasper's violence toward Tibbs, throwing a dart and a bottle at him, are a way of hinting at the violence that the pups might eventually face. By attacking Tibbs, a resourceful adult character, the point is made without yet threatening the helpless pups.
While there is good animation in this sequence, the assignment of shots is very broken up. Nobody gets control of a character and there are few instances where an animator can put together a succession of shots. Cliff Nordberg does some nice Tibbs. Amby Paliwoda does some nice Horace and Jasper. Jasper in this sequence is very much like Bud Abbott of Abbott and Costello. He's teamed with a dumber partner and doesn't hesitate to treat his partner poorly for his own amusement and selfish ends.
Nobody does weak animation here, but the sequence is very much a jigsaw puzzle of different animators' shots. They assemble well, but none of the animators really dominates.
Note the paint mistake on the Colonel's beard in shot 76. There's also a slight continuity error with Horace in shot 99. He enters with two sandwiches. When Jasper slaps him on the belly, one drops to the floor and then vanishes from the film. As Roly later steals the contents of the remaining sandwich, maybe there were shots of Roly eating the first that were cut.
There is quite a bit of re-used footage in this part of the film. Tibbs at the window in shots 78.1 and 78.4 are at least partially lifted from Eric Larson's Figaro animation in Pinocchio. Tibbs wiping the window is lifted from production #2396. As Hans Perk's list of production numbers does not include it, it doesn't appear to come from a full-length feature. The same is true for 86.1. Perhaps these lifts came from the compilation features of the 1940s or perhaps from a short. 86.1 reminds me of Goofy. Perhaps it's a scene that Reitherman animated himself and remembered it for use here.
There is lots of puppy re-use from earlier in the film. Shots 84, 85, 90, 110, 111, 113, 118, 118.1, and 119.1 are all from earlier shots in whole or in part. Many of these shots are from sequence 004 where the pups are watching Thunderbolt and Dirty Dawson on TV. What the pups are watching in this sequence is Springtime, a Silly Symphony from 1929.
There are many shots in this sequence where two animators are credited for a single character. For instance, on shot 91, featuring only Tibbs, both Cliff Nordberg and Hal King get credit. I don't know how the work would be broken down. Would Nordberg have posed out the shot with King doing the animation? Would Nordberg have done the first pass and King do the revisions? It's a mystery to me.
I want to point out a couple of links that relate to earlier sequences. Peter Emslie has done a post about animals as human types and has used the characters of the Captain, the Colonel and Tibbs as examples.
Julius Svendsen is the animator of the horse in the barn known as the Captain, as well as other characters in this film. He is one of the many mostly anonymous animators who contributed to Disney features for years but who receive little attention. Michael Sporn has posted a children's book (part one and part two) based on So Dear to My Heart, lent by John Canemaker. The art is by Svendsen and provides a rare opportunity to see some of his work outside Disney's animated films.