The tendency to bleed is a symptom which many times evades all efforts to find an explanation for its cause or a remedy for its relief, and the classification of the various forms of this tendency is very unsatisfactory. The knowledge we have of its causes is entirely inadequate for satisfactory treatment. Cases are frequently reported, especially in the more severe forms of the condition, which do not fit into any classification, and the possible relations between groups are not well understood. The two patients (61 and 62) whose records are presented here are sisters belonging in the fifth generation on the accompanying chart. Of ten half-brothers and half-sisters (51 to 59 inclusive) none show the tendency to bleed, but six out of nine children of the patients' mother had a bleeding tendency and five of them are dead as the result of it (60, 61, 64, 66 and 67).