For of the 450th anniversary of the Royal College of Physicians and its first joint conference with the American College of Physicians, in Boston, we have chosen to span the Atlantic with a comparison of sarcoidosis in London and New York city. We have analyzed and compared a series of 537 personally studied patients with both clinical and histological evidence of sarcoidosis in London with a group of 311 patients delineated by the same rigid diagnostic criteria in New York city. It is clear from these data that most organs of the body are invaded, emphasizing the fact that sarcoidosis transcends boundaries demarcating various disciplines and makes specialists realize that it is a disorder of general medical interest. Sex, Age and Ethnic Background Women outnumbered men by two to one and Negroes constituted nearly one half the New York patients (Table 1). This was not so in London where women