Electric Excitation of Nerve

The electrical behaviour of nerve has provided the same fascination for physiologists as the conduction of electricity through gases for physicists. The former has not yet led to such striking changes in theory and practice as the latter, but that may be due to the fact that the nerve is more complicated than the atom. Already it has given essential and objective knowledge of the physiology of movement and sensation, and it is reaching out into the nervous system and the brain itself. The elementary facts in the electrical behaviour of nerve are those of electric excitation and of the electric manifestations of activity. It is clear now that the conduction of the nerve impulse is a function of these two, each element of the nerve being excited electrically in turn by a neighbouring active region. The extent to which transmission over neuro-muscular junction or synapse depends on similar electric factors is not yet certain. In the " accommodation " of nerve to a gradually increasing or maintained current we have an obvious parallel to the adaptation of sensory organs. In the changes of excitability of nerve under the influence of electric current we have clues to the nature of central nervous phenomena. The subject, therefore, of electric excitation is one not only of intrinsic interest in itself but of almost certain importance in neurology. It is with such ideas in mind that one can turn to Electric Excitation of Nerve, by Dr. Bernhard Katz. The author (originally from Gildemeister's laboratory in Leipzig) has been intimately in touch, since 1935, with English physiology, particularly on this subject, and in 1938 was invited by the editors of the Ergebnisse der Physiologie to write a review of electric excitation for their journal. The finished manuscript was submitted and accepted, but refused by the German publishers on "racial " grounds; though they offered to publish it if Katz's name could be coupled with that of an Aryan colleague. It was playfully suggested that perhaps Mr. Winston Churchill might accept joint responsibility for the review, but other counsels prevailed and the manuscript was returned. The Oxford University Press then offered to publish it, and it was rewritten in the form of a monograph. It is an admirable survey of the subject, written in a clear and concise way which makes it as intelligible as a rather difficult and complex subject can be. The last chapter, on the initiation and propagation of the nerve impulse, will be perhaps the most interesting to the general reader, since it deals with novel and obviously fundamental ideas which are not yet in the textbooks, and can scarce but have an important bearing on neurology. It contains an excellent bibliography, not neglecting the older work of famous German authors-it is striking, as Katz says, how little has been added to our fundamental ideas which was not already suggested by Hermann, Bernstein, and Cremer long ago; though convincing experimental evidence is new. But the monograph is not merely a summary: it has adopted the standpoint of recent English physiology and has avoided the dangers both of producing an uncritical book of reference and of pushing any special theory too far. It will not be easy reading for those unacquainted with electrophysiology; but for those who are it will provide a store of critical thought and information. A. V. HILL.