EN
As, Fe, Cd, Pb, Zn and Sr contents were determined in the organs, tissues and body liquids of cows suffering from enzootic bovine leukaemia. Moreover, the concentration of Mg was determined by the plasma spectophotometry method under the control of a computer combined with an analytic apparatus (Philips Scientific PU 7000). An increase of all the metals was observed and a drop in Mg content. Bovine leukaemia virus (leukomovirus) probably induces the permeability of heavy metals to cells which undergo transformation due to the metals as cocarcino- genic factors.