The primary concern that the elder doctor seems to be addressing is that there are so many ways that a doctor's psychology could interfere with his ability to succeed. In a way, the doctor is urging his young protege to accept responsibility for his ethical progress as a person, understanding that any kind of aversion or laziness could mean real human death for his patients.
He doesn't pull any punches. He reminds the doctor that he will encounter death frequently, and he says that he will need to consult the gift that the doctor sent (a medical textbook used to diagnosis patients) when doing autopsies on the dead. The dual service of the textbook is a reminder that the stakes of medicine (especially surgical medicine which is what the stories treat) are death. The deaths of patients are difficult to discuss, but he does it anyway, because he feels it is important.
This underscores a need in the medical community for a deep appreciation for human life. The stories lend the medical student with the Humanities study that he needs to appreciate. By categorizing medicine within the broader context of man's desire for life, and the meaning of life, the elder doctor hopes to instill something ineffable that might help the young doctor to take responsibility not only for his medical practice, but for his ethical growth as a person.
