I live in a house that is 100+ years old. It has finished wood floors that I suspect may be the original subflooring. I don't know my woods really well, but I think it may be pine. In some places, there are gaps between the planks--maybe 1/16 to 1/8 inch wide. These have been filled with a wood putty of some kind, smoothed over, and finished (apparently quite some time ago; I have owned the house for only a few months). This has started to dry out and under the punishment of dogs' toenails, flake and chip out in places. I know diddly-squat about flooring. The gaps/cracks aren't large enough to see through to the lower level or anything, and the floor is very tight (not creaky, crackly, or "floaty" at all). Should these be filled back in? If so, what would you suggest I use?
Thanks in advance for all advice, Jo Ann