The structure of the bacterial cell has been the subject of numerous investigations since the early years of bacteriology. Up to a quarter of a century ago a considerable literature accumulated, as it is easy to see from the last extensive review, "Die Zelle der Bakterien,"' published by A. Meyer in 1912. Since then the literature has been relatively scanty. It can, therefore, be said that this interesting branch of bacteriology has been sadly neglected in recent years. The writer knows of only one other lecture course in this country, aside from his own, which teaches cytology and morphology of bacteria exclusively. Surprise is often expressed that there should be enough known on the subject to justify a course in cytology and morphology. The following brief review is an outline of the main topics investigated and the progress made.