Obituary: Professor J. Z. Young

The zoologist and comparative anatomist J.Z. Young was acknowledged by many biologists to be the most distinguished invertebrate anatomist of this century.

His main interest was the functional anatomy of the nervous system, the details of how its nerve cells were arranged and how they were linked together on the one hand, and on the other, what the properties of a nervous system might be, how we and other animals learned, and what was the basis of memory.

Directed towards biology by A.G. Lowndes, his teacher at Marlborough College, Young later wrote that he loved it from the first day, dissecting a rabbit before breakfast. He went up to Magdalen College, Oxford, as a Demy, to read zoology and, gaining the best First, was awarded the Naples Scholarship upon graduation, to study the visceral autonomic nervous system of fish.

Two excellent papers on the fish autonomic system resulted, but the most important consequence of his early visits to Naples was his introduction to the cephalopods, the group containing octopus, cuttlefish, squid and nautilus. His first published papers, in 1929, both dealt with cephalopods. One was on a new organ he had discovered next to a nerve ganglion in octopus and the other on the degeneration of cuttlefish nerve fibres after section. Thus began his remarkable research career, spanning no less than 65 years from the date of these first papers. In all, he wrote more than 150 articles on cepha-lopods as well as several books, and at the time of his death was working with Marion Nixon on a large book The Brains and Lives of Cephalopods.

Whilst searching in squid for the new organ he had discovered in octopus, Young observed large transparent tubes in the nerves passing from the star-like stellate ganglion to the mantle muscle which powers squid jet propulsion. These tubes arose from masses of small nerve cells in the ganglion and after some simple experiments, Young was able to show that they were in fact enormously thick giant nerve fibres. Nerve fibres in most animals, and indeed the other nerve fibres in squid mantle nerves, are only a few thousandths of a millimetre in diameter, but the giant nerve fibres or axons in large squid may be up to a millimetre in diameter.

The discovery of the squid and cuttlefish giant axons, first announced in a short note in 1934, was of cardinal importance. In a series of magisterial papers, many in the Philosophical Transactions of the Royal Society (where Young regularly contributed long superbly illustrated papers on cephalopods for over 50 years) he described the very complex anatomy of the giant fibre systems.

As a zoologist, he was not only interested in the anatomy, but also in how the system functioned, and he was able to show by measuring the speed of conduction of giant fibres of different diameters, that the size of the giant axons was related to the need for rapid escape responses from the mantle muscles. Curiously enough, giant cells and axons in the cephalopod brain had been discovered by another anatomist, L.W. Williams, in 1909, but he gave no figures and misunderstood the arrangement of the fibres, so that it was Young's prepared mind that understood the system and worked it out correctly, seizing in his first note the great significance of his discovery.

The importance of the giant axons to neurophysiology lay in their accessibility and colossal diameter, compared with other "normal' nerve fibres. Their size permitted the experiments by Sir Alan Hodgkin and Sir Andrew Huxley in which they actually inserted two electrodes into the axons. This led to the understanding of the excitability of the nerve membrane and the mechanism of nerve conduction. It even became possible, as was found later, to roll out the contents of the axon with a miniature roller, and to replace them with artificial solutions. Work on the giant axons, and their surrounding sheath cells, has continued ever since, not only by those interested in excitable membranes and synaptic transmission, but also by biochemists and microscopic anatomists.

Space does not permit description of all of Young's later anatomical discoveries. As well as the detailed anatomy of different cephalopod brains, and the anatomy of curious and rare cephalopods, he worked out the organisation of the eye muscles (including a muscle which spans the head transversely linking the two eyes) and the statocysts (extraordinarily, not so different in principle to our own ears), and had just completed with a colleague a fortnight before he died, a remarkable paper, on the cephalopod rasping rows of radular teeth, in which he was able to explain the existence of structures found in many other molluscs whose function had not been understood. He confided to me that he felt this last paper was one of his best.

In addition to his anatomical work, Young pioneered the use of the octopus for experimental neurobiology, and worked for many years each summer at the Stazione Zoologica in Naples examining the changes in visual and tactile learning and in memory which resulted from different brain lesions. Of course this went hand in hand with studies of brain anatomy, and led to later more philosophical articles and books such as Doubt and Certainty in Science (1950), Programs of the Brain (1978) and Philosophy and the Brain (1982). As he remarked in a recent essay, he was concerned to show how knowledge about brain functions can help in everyday human affairs.

The visits to Naples, begun in 1928, continued whilst he was a Fellow of Magdalen and University demonstrator in Zoology, until the beginning of the Second World War. During the war, Young worked in Oxford with H.J. Seddon studying nerve injuries and their repair by grafting. After the war, he became the first zoologist to be appointed to a chair of anatomy, at University College London, in 1945. Further research visits to Naples were made from the late 1940s until the early 1980s. The great distinction of this regular scientific visitor was fittingly recognised in 1991 when Young received the freedom of the city he was so fond of and had known so long.

As Professor of Anatomy in University College 1945-74, he wrote The Life of Vertebrates (1950) and An Introduction to the Study of Man (1971), the former making his name familiar to generations of students, influencing them more than any of his other contributions.

In person, J.Z. (as he was universally known outside the circle of his friends and pupils to whom he was John) was tall and commanding, latterly with a mane of silver hair, and his personality was a strong one. Perhaps his most striking and engaging characteristic was his infectious enthusiasm for whatever he did, whether it was about the Roman snail colony in Wychwood, or his latest experimental results.

He had a formidable intellect and an even more formidable capacity for work. Even in his eighties he worked a long day, pausing for an hour in the pub before a late dinner and continuing in the evening. Sundays were devoted to walking 20 miles or so, but anyone who knew him cannot imagine that he was even then not pondering his next paper or book.

His marriage to the painter Raye Parsons was supremely happy, and he owed much to her. She organised a magnificent lunch for his 90th birthday earlier this year, and it was astonishing how many of his former pupils and friends came from all over the world to see John and to wish him well.

He was in truth a scientist who was exceptionally good at what he did, and loved doing it. For him, research was certainly a way of life rather than work. He received during his life many distinctions: elected Fellow of the Royal Society at the early age for a biologist of 38, he received the Royal Medal of the society in 1967, the Linnean Gold Medal of the Linnean Society in 1973, and was given the unusual honour for a scientist, which pleased him much, of election as an honorary fellow of the British Academy in 1986. He was also a member of several foreign academies, and was given many honorary degrees.

John Zachary Young, zoologist: born 18 March 1907; Fellow, Magdalen College, Oxford 1931-45, Honorary Fellow 1975; Demonstrator in Zoology and Comparative Anatomy, Oxford University 1933-45; FRS 1945; Professor of Anatomy, University College, London 1945-74 (Emeritus); Fullerton Professor of Physiology, Royal Institution 1958-61; married first Phyllis Heaney (one son, one daughter), second Raymonde Parsons (one daughter); died Oxford 4 July 1997.