Werth said that it had been run by `` a German professor called Spanner '' and `` was a nightmarish sight , with its vats full of human heads and torsoes pickled in some liquid , and its pail full of a flakey substance - human soap '' . According to Werth it had been run by `` a German professor called Spanner '' and `` was a nightmarish sight , with its vats full of human heads and torsoes pickled in some liquid , and its pails full of a flakey substance - human soap '' .