He did some freelance art work for pharmaceutical companies, most notably CIBA, and it tuned out to pay a lot more than his own private practice. He then gave up the practice of medicine and started to make medical illustrations full-time.
Doctors still use and love his illustrations. I have seen them in my current Histology and Physiology classes. There were posters of Netter's illustrations hanging up in the cadaver lab at BYU.
Here's an example of his art:
|From University of Waterloo|
I guess I think he is really cool because I like drawing and I like the human body. It reminds me of when I drew a bunch of pictures to study for my anatomy class.