The con-struction of a simple Perspex electrodialysis cell involving the use of Permaplex ion-exchange membranes or collodion membranes is described. The apparatus can be used for desalting or for fractionation of complex mixtures by electro-dialysis. As an example of the use of the apparatus, meat extract containing 33% of ash was desalted to an ash content of 5.7% without appreciable loss of N. The same meat extract was separated into an anionic, a cationic and a middle fraction by electrodialysis and the constituents were identified by paper chromatography.