Here's a breakdown:

* Hematology is the branch of medicine that deals with the study of blood, blood-forming organs (bone marrow, lymph nodes, spleen), and blood diseases.

* Hematologists are medical doctors specializing in hematology. They diagnose and treat blood disorders, including anemia, leukemia, lymphoma, and clotting problems.

They might also be involved in research, developing new treatments, or working in blood banks.