Three years ago when inaugurâting this system of periodic tours in Europe, my primary object was to study the equipment of laboratory buildings, laboratory rooms, and the designs of apparatus, with a view to introducing many of these ideas into the construction and equipment of the Nutrition Laboratory. As has been said before, this has been hi^ily beneficial. On my tour in the spring of 1910, my object was quite different, namely, for consultation with European investigators in regard to the planning of ex¬ periments, securing more detailed opinions and instructions in regard to many published researches both from the Nutrition Laboratory and from other laboratories, and particularly to consult with the eminent clinicians of Europe with regard to the research on diabetes now in progress in the laboratory. The uniform courtesy and consideration with which I was received in all labo¬ ratories is a new testimonial to the appreciation of the Nutrition Laboratory by foreign investigators. While these were primarily the reasons for talcing this trip, other material of value to the Laboratory was simultaneously accumulated. Thus, approximately 80 to 100 photographs were taken of new or modified apparatus which had been developed since my last visit of three years ago, and a col¬ lection of reprints, supplied by the different investigators, was obtained for the Laboratory, these reprints being frequently accompanied by notes made by the investigator or myself with regard to particular points in the publi¬ cation. Opportunity was also afforded to purchase a number of pieces of appa¬ ratus of different types, which seemed to me advantageous and desirable for use in .the Nutrition Laboratory. The tour covered very much the same ground as that taken three years ago, somewhat more time being given to Scotland and England than previously. A list of cities and institutions visited, as well as the investigators personally seen and consulted, is given on the page following the title page. Before leaving for Europe a letter was sent to each one of the physiologists and chemists