    Sentence 1: How many bodies did Public Health  England exhume?    Sentence 2: Archaeologist Barney Sloane has argued  that there is insufficient evidence of the extinction of  a large number of rats in the archaeological record of  the medieval waterfront in London and that the  plague spread too quickly to support the thesis that  the Y. pestis was spread from fleas on rats; he argues  that transmission must have been person to person.