As expected, the Kindle version of Black's Medical Dictionary cannot be faulted on it's content.
Unfortunately, it is not set up as a dictionary on the Kindle in the same way as the OED and so you cannot set it as the default dictionary for the device to look up terms in Kindle textbooks and PDFs. Neither does it let you search for terms and definitions easily within the dictionary (other than as you might search for a word or phrase within a book). Finally, whilst words in the definitions which are themselves defined elsewhere in the volume are highlighted in capitals, they are not hyperlinked and so not easy to cross reference for readers.
Given the price of the book, it's a real shame that this basic functionality on the Kindle has been overlooked and I hope Blacks consider including it in future revisions.