|    |          |            |            |.           |             | |   |          |            |            |.           |             | M   M          M            MB           F.           F             F    |                                    |.           |             |    |                                  Mother   +--+--+---+--+--+   |   +----+                                 |.     |  |  |   |  |  |   |   |    |                                 |.     M  M  MB  F  F  F   |   M    F                                 |.                         |     Not Married                           |.             +---+---+---+---+                                           |.             |   |   |   |   |                                           |.             MB  M   MB  M   M                              .............|.                         +-----+-----+-----+-----+-----+                         |    .|    .|     |     |     |                         |    .|*   .|*    |     |     |                         M    MB    MB     F     F     F F = Females. M = Males (not bleeders). MB = Males (bleeders) ** the patients observed by the authors. The dotted line shows the transmission of the disease to our patients through four generations. The disease is met with in boys who are otherwise healthy, and usually manifests itself during the first few years of life. In rare instances profuse hæmorrhage takes place when the umbilical cord separates. As a rule the first evidence is the occurrence of long-continued and uncontrollable bleeding from a comparatively slight injury, such as the scratch of a pin, the extraction of a tooth, or after the operation of circumcision. The blood oozes slowly from the capillaries; at first it appears normal, but after flowing for some days, or it may be weeks, it becomes pale, thin, and watery, and shows less and less tendency to coagulate. Female members of hæmophilia families sometimes show a tendency to excessive hæmorrhage, but they seldom manifest the characteristic features met with in the male members. Sometimes the hæmorrhage takes place apparently spontaneously from the gums, the nasal or the intestinal mucous membrane. In other cases the bleeding occurs into the cellular tissue under the skin or mucous membrane, producing large areas of ecchymosis and discoloration. One of the commonest manifestations of the disease is the occurrence of hæmorrhage into the cavities of the large joints, especially the knee, elbow, or hip. The patient suffers repeatedly from such hæmorrhages, the determining injury being often so slight as to have passed unobserved. There is evidence that the tendency to bleed is greater at certain times than at others--in some cases showing almost a cyclical character--although nothing is known as to the cause of the variation.