Mark Twain got it

From "Two Views of  the Mississippi."
Picking up on the transition from innocence to experience that William Blake explores in his poetry, Twain encapsulates the gain that also entails loss:

Now when I had mastered the language of this water and has come to know every trifling feature that bordered the great river as familiarly as I knew the letters of the alphabet, I had made a valuable acquisition. But I had lost something, too. I had lost something which could never be restored to me while I lived. All the grace, the beauty, the poetry, had gone out of the majestic river! 

Twain offers further details and then suggests a parallel with the medical profession:

 Since those days, I have pitied doctors from my heart. What does the lovely flush in a beautyʹs cheek mean to a doctor but a ʺbreakʺ that ripples above some deadly disease? Are not all her visible charms sown think with what are to him the signs and symbols of hidden decay? Does he ever see her beauty at all, or doesnʹt he simply view her professionally, and comment upon her unwholesome condition all to himself? And doesnʹt he sometimes wonder whether he has gained most or lost most by learning his trade?   

Read more in http://uncommoncontent.blogspot.com/2016/07/innocence-and-experience.html