The course of the blood through the heart of the fetal mammal, with a note on the reptilian and amphibian circulations

The problem of the course of the blood through the heart of the fetal mammal has been taken up because there sre three distinct theories regarding the fate of the blood entering the heart through the superior and inferior caval veins. Each of these theories is based upon anatomical findings-a correlation of function to structure, and while injection experiments hare been carried out which seem to substantiate each theory, experimental evidence derived from a study of the fetal circulation in the living embryo is entirely lacking. It is our purpose, therefore, to review the important literature ; to state the position of the various theories together with their modifications ; to analyze critically the evidence produced by the observers ; to present the results of personal findings in the living mammalian embryo; and to offer a general summary of the physical, anatomical, and pathological evidence in favor of the one as opposed to all other theories. Finally to give preliminary account of our observations on the circulation of the reptile and amphibian. The literature up to the time of Harvey (1628) is drawn from Dalton’s excellent work. Extremely comprehensive reviews are to be found in Knabbe’s dissertation in Latin, and also in Kilian’s article in German. With the exception of the first six references, where direct control is offered by comparison with the original text, and of TVolff’s treatise, the articles hare been read personally. The reader is referred to literature reviews mentioned for more exhaustive study.