Pyroblock – used since the early 1900’s for wall partitions. Sometimes it has asbestos in it – but not here. Pretty soft stuff once you get through the plaster coating. Probing the wall for the architect. Carving it up for the electrician.
Pyroblock 
Probing the wall in the kitchen 
building systems 
outlet box additions for lighting and media center. 
adding an outlet box for TV 
to offset switch box 
Seroy Inc. - contractor 