I've just bought a 1880's house built from brick and stone with a small, quite damp cellar. I noticed that at low level on the wall adjoining next door, the mortar is very soft in one place. I scraped it out and around the bottom course of bricks for the length of 18 inches or so there is now practically no mortar at all and I can push a metal rod upto about 10 inches deep into the wall in places. The mortar also came out in the course or two above but in a smaller patch. The mortar I scaped out was like mud and seemed to be wetter the deeper I scraped. I'm not sure how to replace the mortar as if I put new mortar in I think it won't set properly as the wall is permanently damp. Also, would I be better off leaving it altogether so that any damp behind the wall can escape? Any advice would be much appreciated.