At each stage of my career, I entered some constancy, a whole new approach to my science. When I left the NIH and went to Harvard, I joined the Department of Pharmacology. But the reason I went to Harvard is they had a wonderful Department of Neurobiology, founded by Steve Kuffler from the Department of Pharmacology. It was the first one in the country, in the world, to form a department and bring together physiologists, anatomists and biochemists. A legendary department, in their own eyes legendary.

By the time I went back there the second time, it wasn't so legendary. It had gotten very stale and stodgy, so we revolutionized it. But at each stage the emphasis of my career changed. When I went to Harvard, I was more focused on, as I said, pharmacology and physiology and teaching. That's what I missed at the NIH, the education aspects of science. Having students, graduate students, so I loved that. And I emphasized more the biochemistry when I got to Harvard. And not just the phenomenon, but the mechanisms, how do the nerves do this?

We began to purify from the spinal cord and the chick brain, substances which when added to muscle would increase the level of acetylcholine receptor. I want to be clear on why we took that as an assay. When I found that adding nerve to muscle caused the formation of a synapse, it also caused the accumulation of acetylcholine receptors. What we could then determine was the point of contact of neurite nerve and muscle. The thought arose that there must be something coming from the nerve that is signaling to the muscle to put more receptors here.

So, we began to act like biochemists, and it worked. Tom Jessell, who was in my lab at the time, began doing extracts of brain tissue. We didn't go to cow brains, we stayed with chicks. I don't know why; it was just a bias. If this is a phenomenon in chicks, it'd be better to stick with the chicks.