There has been described within recent years a symptom-complex characterized especially by cyanosis, enlarged spleen and increased number of red blood corpuscles. Although cases had been reported and the subject had been referred to in the literature previously, it was not until Osler, in 1903, published the results of a thoughtful study of the disorder that it received the attention its importance warranted. Since that time additional cases have been recorded and the clinical account has been supplemented by the pathologic findings in a few cases that have come to autopsy. An admirable description of the clinical and pathologic features of the disorder is given by Dr. John H. Watson1 on the basis of personal observation in conjunction with a study of the literature of the subject.
The disorder in question continues for many years. It has been observed most commonly at the middle period of life, and the largest