In the early part of this paper the author adverts to the antiquity of researches into the causal relations of health and mortality. Nevertheless, long as these have been the subject of inquiry, the literature of medical meteorology is meagre in the extreme; and in proportion to the time and labour bestowed upon the many other branches of medical science, this department may justly be regarded as having met with unmerited neglect. Reference is made, however, to the names of many eminent physicians, whose researches into the influence of weather upon the human constitution have contributed not a little to adorn the medical literature of the present century.