Cows were the most efficient humidifiers I came across. Fifty or sixty of them in pens spread along the full length of the cabin produced an immense amount of humid breath. During the cruise there was no real problem, the trouble started in the descent. Water poured out of the sound proofing in the flight deck roof, soaking everything below. The Britannia was the original all electric aeroplane and prone to short circuits, popped fuses and sticking relays, water was not welcome. Experienced hands donned their hats and dirty old raincoats before TOD.
Fortunately these deluges never caused any problems for me, but an angry Boar bursting through the flight deck door with the loadmaster hanging on to its tail was a different story when it buried its nose in the central pedestal as we crossed the outer marker on an ILS approach into Malpensa. The situation was saved after I abandoned the approach and the flight engineer grabbed the pig's left ear, the first officer took it's right ear and the loadmaster was pulling it by the tail. They managed to force the monster animal into it's pen at the front of the cabin and bent the bars back into place while we were in the holding pattern and I was trying to explain what was happening to ATC.