The method of teaching, however, that uses the pupil’s experience as a basis upon which to build has a value not to be overlooked. The fact that such expressions as those quoted above are so easily remembered proves the value of connecting new knowledge with the pupil’s experience. But _the inadequacy of this experience must be recognized_ and taken into account. The concepts of the average pupil are entirely too indefinite and limited to supply the necessary _foundation for a science_ such as physiology. Herein lies the great value of experiments and observations. They supplement the pupil’s experience, and increase both the number and definiteness of his concepts. No degree of success can be attained if this phase of the study is omitted. The best results in physiology teaching are of course attained where laboratory work is carried on by the pupils, but where this cannot be arranged, class experiments and observations must suffice. The Practical Work described at the close of most of the chapters is mainly for class purposes. While these serve a necessary part in the development of the subject, it is not essential that all of the experiments and observations be made, the intention being to provide for some choice on the part of the teacher. A note-book should be kept by the pupil. To adapt the book to as wide a range of usefulness as possible, more subject-matter is introduced than is usually included in an elementary course. Such portions, however, as are unessential to a proper understanding of the body by the pupil are set in small type, to be used at the discretion of the teacher. The use of books of reference is earnestly recommended. For this purpose the usual high school texts may be employed to good advantage. A few more advanced works should, however, be frequently consulted. For this purpose Martin’s _Human Body_ (Advanced Course), Rettger’s _Advanced Lessons in Physiology_, Thornton’s _Human Physiology_, Huxley’s _Lessons in Elementary Physiology_, Howell’s _A Text-book of Physiology_, Hough and Sedgwick’s _Hygiene and Sanitation_, and Pyle’s _Personal Hygiene_ will be found serviceable.