Simultaneous with Mr. Galton's article, there appeared a communication in the _Contemporary Review_ entitled "The Prayer for the Sick: Hints toward a serious attempt to estimate its value," with the indorsement of Dr. Tyndall. The proposal contained in this communication came to be generally known in newspaper slang as "Tyndall's Prayer-gauge," though Tyndall was not its author. The proposition was that "One single ward or hospital under the care of first-rate physicians or surgeons, containing a number of patients afflicted with those diseases which have been best studied, and of which the mortality rates are best known, should be, during a period of not less than three to five years, made the subject of special prayer by the whole body of the faithful, and that at the end of that period the mortality rates should be compared with the past rates, and also with those of other leading hospitals similarly well managed during the same periods." This experiment, the writer thinks, offers "to the faithful an occasion of demonstrating to the faithless an imperishable record of the power of prayer." There was a tone of moderation and candor in this proposition which for a moment beguiled the popular mind, and there were Christian ministers so injudicious as to admit that the proposal should be entertained and the experiment tried. But its superficial fairness was delusive, and its plausibility concealed a snare. The writer must have been sufficiently conversant with the Christian doctrine concerning prayer to know that the acceptance of his challenge would be a theological blunder; for there are no unconditional assurances in the Word of God that prayers for health and long life shall always be answered. We presume also that he must have been sufficiently acquainted with medical science to perceive that the acceptance of his challenge would be a scientific blunder, for there are elements in the problem which can not be scientifically appreciated, measured, and recorded. Such, for example, are the temperament, idiosyncrasy, hereditary diathesis, previous habits of life, and mental characteristics of the patients; such the variety in skill, care, sympathy, and almost inspiration among physicians and nurses; such also the differences of climatal, sanitary, and hospital conditions; all these elements, whose varied degrees of potency are incapable of being estimated, enter into the problem and affect the results. The multiplicity and complexity of these elements render the effects as irregularly variable as if each cause had not been subject to any previous conditions.[432] The problem is not even capable of being scientifically presented in terms of experience, and until that is done it can not be subjected to experiment. Suppose the experiment to be tried in the manner proposed by the writer, and the mortality rates to be in favor of the hospital for which prayer had been offered, it