Copy letter from Robert William Frederick Harrison to Professor W M Thornton 'Your paper on bacteria has been referred to me. I cannot tell what property you really equilibrate by altering the surrounding solution. There is no orientating force on the bacteria due to the current unless they are in a steady magnetic field. It might be a polarization static influence or it might be hydrodynamical due to endosmotic and other currents. Thus in my view there is no evidence for much of your exposition - but there is an interesting problem as to what you are really balancing. I do not feel that I can get any further: up to this the physiological referee agrees independently with me.' 20 February 1912