Besides being a good place to do research, NIH was also a good place to learn about new developments in biology. During the course of any given year, most good scientists working on the brain visit the NIH campus. As a result, I was able to speak with many people and to attend seminars in which I learned about the experimental advantages of various invertebrate animals, such as crayfish, lobsters, honeybes, flies, land snails, and the nematode work Ascaris…After about six months of careful consideration, I settle on the giant marine snail Aplysia as a suitable animal for my studies. I had been greatly impressed with lectures I had heard about the snail…The American species of Aplysia that lives off the California coast, and which I have spent most of my career studying, measures more tha one foot in length and weights several pounds…It is a large, proud, attractive, and obviously highly intelligent beast…Aplysia has a small number of cells…In addition, some of Aplysias cells are the largest in the animal kingdom, making it relatively easy to insert microelectrodes into them…It had been found that few nerve cells are uniquely identifiable—that is, the same cells can easily be recognized by sight under the microscope in every single snail. In time I realized that the same thing is true of most other cells in its nervous system, heightening the prospect of mapping the entire neural circuitry controlling a behavior….No one in the United States was working on Aplysia. The only two people in the world who were studying it in 1959 were in France…
As I left NIH in June 1960, I felt a deep sadness, somewhat similar to that which I experienced when I graduated from Erasmus Hall High School. I had come as a novice, and I left as a limited but nonetheless working scientist. (p.145)