My neurone (3 synapses, 2 inhibitory) informms me that this question has been posed before but I cannot remember the answer (barin aluminium too high) What is the vailidity of biochemical measurements of the aqueous and vitreos humour of the eye? Do the mimic serum values PS can anyone point me in the direction of a reference on measurements of things (the technical term is probabaly analytes) in fluids other than blood and urine -- Paul Collinson %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%