The opportunity to observe and study four cases of milkers' nodules during the summer of 1939, and my inability to find in the American literature any description of this disease, prompt this report. This is an occupational infection of milkers which may be widely distributed among the dairying communities of our country. Is is my purpose to give a clinical description of milkers' nodules and differentiate this disorder from other diseases occurring on the hands of milkers, and discuss the cause, pathology and immunology. The initial lesions may vary from one to forty in number and they are usually located on the hands and fingers. The incubation period is from five to seven days after contact with a diseased cow, and the infection enters the human skin through abrasions. At the onset an erythematous papule develops, which slowly increases in size, becoming a firm, elastic, bluish red nodule from 1