=Melæna Neonatorum.=--Another hæmorrhagic condition in which blood transfusion is of the very greatest value is that known as _melæna neonatorum_. Severe hæmorrhage takes place from the bowel of an infant, sometimes only a few hours after birth. The cause is quite unknown, but it is found that absolute hæmostasis is usually brought about by blood transfusion. Horse serum has often been successfully used as in treating hæmophilia, but blood transfusion again has the additional merit that the blood which has been lost is thereby replaced. A single transfusion is usually enough, as the hæmorrhage does not tend to recur when once it has been stopped. For a newly born infant, even if _in extremis_, only a small quantity of blood is needed, so that a transfusion of 50 to 100 cc. is usually found to be enough. Bruce Robertson suggests that, as a good working rule, the amount should not exceed 15 ccm. per pound of body weight. The superficial veins of an infant are exceedingly small, so that the introduction even of a fine needle into the median basilic may be matter of the greatest difficulty. The best method of transfusing an infant, therefore, demands special consideration. A description of this will be found on p. 134 of the present work. The value of transfusion for _melæna neonatorum_ has not been very generally recognized, but a number of striking cases have been reported. Defibrinated blood had been used in 1873 by Sir Thomas Smith as described in Chapter I, but the first case in which whole blood was used was published by Lambert in 1908. Later, in 1910, Welch, and then Schloss, recommended the subcutaneous injection of serum or of blood, but these measures were clearly not so effective as the intravenous transfusion of blood, as has been testified by numerous observers (Lespinasse, Unger, Vincent, Graham, Bruce Robertson, Lapage, Hutchinson, etc.). The patients may be actually moribund, for a new-born infant can only afford to lose a relatively small amount of blood, but even then transfusion is often successful. Bruce Robertson reports that of a series of forty cases of hæmorrhagic disease of the new-born which were treated by transfusion, all recovered except four; of these two died from associated umbilical sepsis, one from intracranial hæmorrhage, and the fourth had already ceased breathing when the treatment was begun. It has sometimes been stated that for transfusing an infant either parent can be safely used as blood donor, on the assumption that the serum reactions are not yet developed. This may sometimes be true, but the fallacies and possible dangers of this are explained in a later chapter.