Study of the threshold dose of penicillin which induces an epileptogenic focus during ontogenesis in the rabbit

: A local application on the cortex surface of a very small drop of Ringer solution containing Penicillin was performed to establish the threshold dose required to elicit and epileptogenic focus and consequently the occuring latency of it. Threshold doses are small (20 - 60 International Units) and show a significant decrease during the maturation of the C.N.S. On the other hand latencies, whatever the animal's age, decrease fairly. The results are confronted to the various supposed modes of action of penicillin, modes which involve a dysfonctioning of the Na+ and K+ ionic pump.