It was indistinguishable from the rest of his life, and Somer learned at his knee.

'For her father, medicine was more than a profession, it was a calling.'

Our profession is our career, how we earn our money. At the end the working day, we can forget about our work and go home and think about other things - family, friends, going out, vacations, etc.

A 'calling' is much more than a profession. It is what we would do even if we were not paid money for it. Nurses are not well paid, yet they are renowned for the amount of care they give. People in religious orders, such as priests and nuns are said to 'have followed a calling', Volunteer workers are the same. It is a belief in giving of yourself to help others.

'It was indistinguishable from the rest of his life,'

Somer's father lived his whole life this way - giving of himself, helping others, being kind, friendly, charitable - not just doing things because he was paid to do them.

'and Somer learned at his knee.'

This is a very common expression. Imagine a man sitting in his chair after a hard day's work. His child idolizes him and sits on the floor next to him with her head resting on his knee. She is watching everything he does, listening to every word he speaks, aware of everything about him, storing it away in her memory. And she will grow up wanting to be just like him.

Children learn by watching their parents . The more they love their parents the more they will want to copy them, to be like them. It is saying that Somer learned to be like her father by following his example.

Many thanks!

Exactly. I'll add that learning at the father's knee means learning at a very early age.