Dissecting eels

One of Freud’s first courses was ‘General Biology and Darwinism’, taught by Carl Claus, who ran the university’s Institute for Comparative Anatomy.

Claus arranged for Freud to spend several months at a marine biology research station in Trieste, where Freud had the task of dissecting 400 eels, undertaking anatomical research in the hope of determining the location of the eels’ genitals – a subject of much heated debate at the time!

Under the microscope

When he returned to Vienna, Freud obtained a post at the university’s Physiological Institute, working under the supervision of the renowned physiologist Ernst Brücke.

Freud greatly enjoyed pure research, seated for hours in a laboratory. He soon became a proficient microscopist, spending much of his time examining tissue samples from humans and other animals under the microscope.

A sketch by Sigmund Freud of the spinal nerve cells of the petromyzon planerei

He spent much of his time studying the nervous system of the petromyzon planeri – the sea lamprey. He meticulously documented the lamprey’s spinal nerve cells, which were the subject of his first scientific publication.

By 1882, Freud had published five scientific papers, mostly on the nervous systems of fish.

A breakthrough in histology

As his studies developed, Freud analysed not only the cells and tissues of lampreys and eels but also of human beings, developing a special interest in the nervous system.

In 1884, he published one of his most important pre-psychoanalytic contributions. While investigating the structure and development of the medulla oblongata – a key structure in the brain – he could not easily see the translucent tissue samples under the microscope.

In order to make the tissue more visible, he developed a new histological staining technique which allowed investigators to examine these previously near-invisible microscope slides more distinctly.

This pioneering work in histology proved to be of great value to anatomical and neurological researchers, helping them to better visualise what could not be seen clearly.

In some respects, Freud’s work on the development of the staining technique was a sign of things to come. It anticipated his subsequent psychoanalytical work, helping patients to understand parts of their unconscious mind which previously could not be seen.