Ah! the fan......... I did not think it appropriate to mention this, but as someone else has started it ..... One day we placed a full sieve stack on the Endecotts in the fume cabinet to separate out some faecal material. To paint this particular picture I will need to explain that the lower collector pan has a stainless steel 6mm spigot drilled in the side and fixed well above the maximum filtrate level. We have also fabricated also another 6mm venting spigot in the centre of the lid so that we can connect the collector to the top sieve chamber with a 6mm clear tube in order to equalise pressures as the sample moves down through the sieves. Stay with me here ...... The whole sieve stack is charged with CO2 to displace air and create an aerobic environment for the Obligate Anaerobes. Still with me? ...... A "slightly" inexperienced lab rat was trying to be helpful by topping up the CO2 to the lower chambers by pulling off the top end of 6mm flexible tube and popping the CO2 gun into it, the aim being to add a little more gas to displace any air before the whole sieve stack was clamped down. Who is already ahead of me (and still standing) ? ....... Being unfamiliar with the pressure, in goes gas ........ out comes homogenised stream of faeces vertically straight into the fume cab extractor fan. Four lab techs almost unable to breath for laughing, all in unison screeched "oh no! the sh*t's hit the fan........" ....... took us weeks to get over it (and clean the fume cab.)