Professor RUSSELL H. CHITTENDEN, _Director Sheffield Scientific School_, NEW HAVEN, CONN. SIR,—In compliance with your verbal request I have the honor to inform you that at this date the men of this detachment are all in good physical condition. Very respectfully, (Signed) WALLACE DEWITT, _1st Lieut. and Asst. Surgeon U. S. Army, Commdg. Det. H. C._ Finally, attention may be called to the photographs of the men, taken just prior to the close of the experiment, from which may be gained some idea of their physical condition so far as it can be judged by external appearance. Certainly, there is no indication in these photographs of any lack of bodily vigor. On the contrary, there is good muscular development, without any undue amount of fat, and indeed every indication of a good bodily condition, coupled with that appearance of quickness and alertness that belongs to the well-developed man, in a state of physiological balance. The photographs scattered through this section of the book, showing the soldiers at work in the gymnasium, likewise give some idea of the lighter forms of exercise they followed each day in the training of bodily movements. * * * * * What now is to be said regarding the nervous condition of the men; _i. e._, their ability to respond to stimulation or, in other words, their mental quickness or reaction time? To study this question, the soldiers were sent with regularity to the Yale Psychological Laboratory, where their reaction time was studied with great care. The results of this investigation are contained in the following report made by Dr. Charles H. Judd, in charge of the Yale Psychological Laboratory. REPORT ON REACTION TIME.