" INCLUSION BODIES," occurring in the polymorpho-nuclear leucocytes of the blood of patients suffering from scarlet fever, were first described by Dohle (191lS1) in November 1911, and were later confirmed by Kretschmer (1912 ') in March 1912. Since then much work has been done by many workers, not only in confirming the observations of Dohle and Kretschmer, but in carrying the investigations further, so as to include Inany other diseases. The so-called inclusion bodies are found in the cytoplasni of the polymorpho-nuclear cells, generally situated near the periphery of the cell. Their shape varies-bacillary, coccoid, diplococcal, streptococcal, pyriform, annular, and amorphous fornis being found. I n size also they vary greatly,-sometimes being little larger than the neutrophil granules, and a t others filling a considerable portion of the cell. The number of inclusions found in one cell likewise is very variable, depending upon the severity of the case, but from one to four is a usual number. They are not present in all the polymorphs, but in scarlet fever about 70 per cent. of these cells contain them, depending upon the type of infection and severity of the case. Extra-cellular forms of inclusion bodies can occasionally be seen, although some writers have denied their presence. These extracellular forms are sometimes to be found lying quite free, and at others attached to the periphery of the polymorphs. Bodies resembling inclusions are also found in specimens of pus taken from scarlet fever patients. I n addition to the various forms of inclusions already mentioned, Dohle describes a spirochztal form, which he has named the Spiyochceta scarlatina?. Curiously, little attention has been paid to these spiro-chaAal forms by writers on this subject. They appear to be quite distinct from the inclusions already described, and occur as thin threadlike structures, sometimes coiled, sonietimes straight, which are only to