more clearly illustrates the sponges 20 placed between the electrodes 14 and 16 and the gel 22 additionally as illustrated in fig2 an aluminum cooling block 26 may be used beneath the tray 12 and placed adjacent the tray bottom 17 however the use of an aluminum cooling block 26 has been found to be unnecessary in nearly all applications and will generally not needed for the operation of the present invention referring to fig1 and 2 the basic operation of the present invention can readily be appreciated the gel 22 may be preferably cast between the sponges 20 or precast and then placed between the sponges 20 a relatively small amount of liquid buffer solution is applied to the sponges 20 soaking them the buffer solution is restrained or held within the sponges 20 preventing the possibility of spillage and requiring only sufficient buffer to perform the electrophoresis with very little waste a voltage is then applied between the electrodes 14 and 16 by power source 18 causing a relatively small current to flow as a result the test sample for example dna fragments is caused to separate various features of the test sample can then be identified using conventional techniques such as staining or viewed directly with ultraviolet light fig3 is a plan view illustrating another embodiment of the present invention that is adjustable to accommodate different.