BACTERIOLOGIC FLORA OF THE LUNGS.

When the pathologist studies the etiology and genesis of an infection, he utilizes the results of the bacteriologic and histologic examination, as well as the clinic observations, in order to form an opinion concerning the disease and the causes of death. Now, there are various sources of error, especially in the bacteriologic examinations of organs after death, which must be carefully eliminated, and among these sourses of error the post-mortem or agonal invasion of the tissues or organisms from the intestines has long been held as an important one. The relation of the lungs to more or less wide-spread agonal invasion of bacteria, especially from the higher tracts, has not been carefully considered. Lucien Beco¹ took up this question and found that the respiratory tracts of ordinary laboratory animals are nearly always sterile from the center of the trachea downward; occasionally he found a non-virulent micrococcus lanceolatus in the