microelectrodes have been constructed for measuring glucose, lactate and other metabolites in tissues with special reference to ischaemic brain and soft tissue wounds. the electrodes were either glass coated, platinum-iridium needles with a tip diameter of 0. 5 to 1. 0 $mu$ m, or carbon fiber electrodes set into glass. the glucose-measuring devices were coated with platinum black by electrodeposition, cleaned in nitric acid to remove residual lead, dipped into a 1 percent solution of glucose oxidase and air-dried in the dark. to confer mechanical stability on the adsorbed enzyme, the electrodes were then treated for 5 sec with a 1 percent solution of glutaraldehyde, washed, dried and coated with cellulose diacetate they were tested for linearity of response in h//2o//2 solutions and in serial dilutions of glucose, after polarization at $plus$ 600 mv against a ssc reference electrode. the lactate transducer was based on a vitreous carbon fiber electropolished in naoh and fused into glass. it was coated with a mixture of nad** $plus$ and nadh and lactate dehydrogenase, air-dried and subsequently coated with cellulose diacetate