Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: fied and signed by each student. This receipt will be retained by the Department. The apparatus is issued in good condition, and students will be held responsible for its return in good condition. The cost of cleaning, repairing, or replacing articles which become damaged will be charged to the students to whom they were issued. A list of the articles liable to be broken beyond repair is posted in the laboratories, with the cost opposite each (see Appendix, Form O, page 101). Students desiring additional apparatus must present a signed requisition for the desired article (see Appendix, Form F, p. 90). Frogs and tortoises will be issued on the presentation of signed requisitions. Students using more than the average number of animals will be charged ten cents for each additional medium- sized frog, and twenty-five cents for each large frog and each tortoise. Every charge will be divided equally between the two members of the pair represented by the name on the requisition. You are advised to keep this letter for reference. Very truly yours, W. T. Porter. Laboratory Experiments The student works in the laboratory fourteen hours a week during six weeks, and ten hours a week during the ten other weeks of the course. Pairing. — Many of the experiments cannot be done by one person. Others are performed more rapidly and with better results by twoworkers than by one. Moreover, discussion and mutual criticism are valuable. The class is therefore divided into pairs. Students are urged to select their comrades for themselves. Those who fail to choose are paired by lot. The pair usually decides to divide the experimental work so that upon one day the preparation of the frog, or other material, shall fall to one student, while the arrangement of the apparatus shall fall...