The horse statue in Nellie's room was melted down in the previous episode about the bell.
At 23:52, Charles is walking to the stream with a bucket. When he gets there and he first puts the bucket in water, the bucket is facing downstream in the zoomed out shot. In the next clip they zoom in on him and the bucket is in the water and is facing upstream.
Miss Beadle gives the class 10 minutes to review their spelling words before having an oral quiz. Nellie and Laura have a brief conversation, and Miss Beadle scolds Laura for talking then says she has about 5 minutes left of review time. Nellie and Laura only talked for about a minute, but the review time has gone from 10 minutes to 5.
As Nelly is screaming while riding down the hill in her wheelchair, modern dental devices can be seen on her teeth.