Transient or persistent cyanosis appearing in new-born infants is not uncommon. In fact, premature infants almost invariably show slight blueness of the skin or mucous membranes at one time or another. Especially is this noted at the time of feeding, and it seems to bear out the supposition of Hess1 that it may in part be due to a weakness of the respiratory muscles, which is exaggerated by the fatigue of nursing. Von Reuss2 expressed the belief that in the premature child, cyanosis is due to lack of cerebral development. In the present study, however, there were definite pathologic lesions to explain the cyanosis in the premature infants as well as in those born at full term.
Lundsgaard and Van Slyke3 have shown that the appearance of cyanosis is coincident with an oxygen unsaturation of 5 Gm. of hemoglobin. Whether the cause of this lack of oxygen