The blood is the highway for the carrying on of traffic on which animallife, from practically the lowest to the highest form, is dependent. It is a very complex tissue, many of the mysteries and intricacies of which are only now being revealed and reduced to the exactness of chemical science. Further research will unfold more, but there will ever remain that realm of darkness, unfathomable by intellect and research, but nevertheless existent.
For this reason, when the facts in the case cannot be reduced to chemical or biologic terms, a certain amount of empiricism in therapeutics must prevail. Empiric therapy will always offer ground for doubt, contention and debate about which reasonable, thinking men may differ. But even in the presence of empiric therapy an unbiased mind and keen clinical observer will obtain much that is of value from blood transfusion in many critical periods in disease.