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Knaysi (1938, 1942, 1944) and Lewis (1941) have reviewed the literature on the existence of a nucleus in the Coccaceae. The first critical attempt to study the nucleus in the Coccaceae was made by Ellis (1902-1903). Using methods developed by Meyer (1912), he was able to detect one or two granules in the cell of Sarcina ureae. However, he was unable to observe similar granules in the cells of Streptococcus pyogenes. Dobell (1911) stated that "the Coccus forms studied possess a single, centrally placed, spherical nucleus in each cell, which divides by a simple amitosis." This type of nuclear organization was found in forms belonging to the genera Micrococcus and Sarcina. Meyer (1912) also described structures he considered to be nuclear in various sareinae. Gutstein (1925) observed an eccentric granule having a diameter equal to one-fourth to one-third of that of the cell in the cells of Staphylococcus, Streptococcus, and Pneumococcus. Gutstein thought these granules consisted of lipoprotein. Schumacher (1926) studied a micrococcus and a gonococcus and claimed a nucleus for both of these organisms. Petter (1933), Milovidov (1935), and Sassuchin (1935) applied the Feulgen technique to various sarcinae and reported that the reaction was restricted to discrete bodies of regular size and shape. Delaporte (1936, 1939) studied five strains of Sarcina and nine strains of Micrococcus; she observed a central structure which was not identifiable with any of the known reserve materials and which gave a positive nucleal reaction. In 1936 she interpreted this structure as a central body, but in her later work (1939) she considered it a granular nucleus. Stille (1937), by reducing the temperature of acid hydrolysis to 40 C, demonstrated localized, positive nucleal reactions with various bacteria, including Sarcina. Piekarski (1938, 1939a,b) studied Sarcina alba and various staphylococci, among other bacteria, microchemically and with the ultraviolet and the electron microscopes. In Sarcina alba and the staphylococci studied he found a Feulgenpositive granule which he called a "nucleoid". The electron microscope failed to resolve any structure in the "nucleoid", which led Piekarski to believe that it was not made up of individual elements (chromosomes).

EVIDENCE FOR THE OCCURRENCE OF MITOSIS IN THE MICROCOCCI