We describe a quantitative histological study of 34 breast biopsies using a marker for human macrophages, the monoclonal antibody EBM/11. Seventeen of the biopsies were of malignant tumours. Both benign and malignant breast tissue contained large numbers of macrophages with significantly higher numbers occurring in the malignant group. An analysis was made of macrophage counts according to stage, grade and prognostic index of the malignant tumours. There was no correlation between macrophage numbers and any of these parameters in malignant breast tumours. We discuss the possible reasons why some earlier studies (using other markers such as lysozyme), have shown an apparently insignificant number of intratumoral macrophages. Images Figure 1 Figure 2

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Using a panel of monoclonal antibodies against a variety of lymphoid and non-lymphoid antigens the immunohistological staining pattern of giant cells from a case of giant-cell tumour of bone has been compared with that of osteoclasts from the developing ends of fetal long bones. Only EBM-11, an antibody reacting with a wide spectrum of macrophages, stained both osteoclasts and giant cells; stromal cells and osteoblasts did not react. This indicates that osteoclasts and giant cells are phenotypically and presumably functionally similar. It is argued that the osteoclasts and the tumour-derived giant cells in bone are derived from a similar mononuclear precursor.

In previous papers (Long and Bliss, 1934; Long, Bliss and Walcott, 1934) the cultural characteristics and distribution of minute hemolytic streptococci were discussed. These may be summarized as follows: Minute hemolytic streptococci produce extremely small colonies, ranging in size, in poured blood agar plates, from complete invisibility to 0.13 mm. in diameter after 18 hours and from 0.14 to 0.40 mm. after 48 hours growth. The zone of hemolysis, which is of the beta type, may be from 2' to 18 times as large as the colony. The organisms, as observed in smears, are about two-thirds the size of ordinary beta streptococci. They tend to lie in clumps, although moderately long chains also are present. They are amphophilic to the Gram stain. They are easily grown in blood broth and blood agar and in plain broth containing as little as 0.075 per cent glucose. Cultures in blood broth under a vaseline seal have been found to be viable after a year in the refrigerator. Most of the strains were isolated from throat cultures, some from normal individuals, more from patients suffering from nephritis and rheumatic infections. We are indebted to Dr. Rebecca C. Lancefield and to Drs. Beatrice and David Seegal for a number of strains.2 Fifty strains, isolated from 44 individuals were studied in detail. None reduced methyl

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In a recent brief report (1) we discussed the isolation of small, amphophilic cocci which possess the power of producing the beta type of hemolysis in poured plates of rabbit's blood, sugar-free agar. These minute organisms resembled the ordinary type of beta hemolytic streptococci in many of their morphological and cultural characteristics. They were isolated from the rhinopharynx in a variety of diseases and from normal human beings, but were recovered most frequently from the throats of individuals suffering from glomerular nephritis or progressive rheumatic infection. These organisms occur in pairs, short chains and masses and are one-half to two-thirds the size of ordinary beta hemolytic streptococci. While it seems unlikely that these organisms have not been previously observed, a thorough search of the available literature has failed to reveal any description of them. In this report their cultural characteristics will be described. MethodsTechnique of Primary Isolation.--The majority of our strains have been isolated from the throats of human beings and we believe that the method of swabbing the throat is of prime importance. We have found that cotton-tipped sterile twisted wire swabs are ideal for this purpose. They must not be tipped with too much cotton. The ordinary cotton-tipped, wooden applicators which one generally encounters on hospital wards are too bulky and too difficult to maneuver in the process of swabbing a throat. It is our practice to rub thoroughly each tonsil or tonsillar fossa, exploring the tonsillar crypts, if any are present, and