CONTENTS. The Sense of Hearing in Frogs. By ROBERT M. YERKES. (From the Harvard Psychological Laboratory.) With seven figures in the text. The Reactions of Ranatra to Light. By S. J. HOLMES. (From the Zoological Laboratory of the University of Michigan.) With six figures in the text. Literary Notices. 279 305 350 THE JOURNAL OF COMPARATIVE NEUROLOGY AND PSYCHOLOGY is published bi-monthly. The annual volume of six numbers comprises about 500 pages, with plates and text-figures. The subscription price is $4.00 a year, strictly net (foreign subscription, $4.30, 18 s., M. 18, 22 fr., L. 22), postage prepaid. Authors receive 50 reprints of their papers gratis and additional copies are supplied at cost. All MSS. and matter for review relating to the Structure of the Nervous System and all business correspondence should be addressed to the MANAGING EDITOR AT DENISON UNIVERSITY, GRANVILLE, OHIO. Editorial Matter relating to Comparative Psychology and the Physiology of the Nervous System should be sent directly to DR. ROBERT M. YERKES, PSYCHOLOGICAL LABORATORY, HARVARD UNIVERSITY, CAMBRIDGE, MASS. Entered as second-class matter in the Postefice at Granville, O. J. MARK BALDWIN, Johns Hopkins University S. I. FRANZ, McLean Hospital, Waverley, Mass. S. J. HOLMES, University of Michigan B. F. KINGSBURY, Cornell University ADOLF MEYER, N. Y. State Pathological Inst. C. LLOYD MORGAN, University College, Bristol A Published bi-monthly DENISON UNIVERSITY, GRANVILLE, OHIO ས་་༽ Neurology and Psychology. PUBLISHER'S ANNOUNCEMENT. Back numbers of most issues of this Journal may be had separately at the rate of $3.50 per volume for the first thirteen volumes and $4.00 per volume for subsequent issues, postage extra. A few of the numbers, however, will be sold only in complete sets. Single copies of current issues 75c. CONTENTS OF RECENT NUMBERS. Volume XV, Number 4, July, 1905. Seven figures. The Sense of Hearing in Frogs. By ROBERT M. YERKES. Volume XV, Number 3, May, 1905. The Morphology of the Vertebrate Head from the Viewpoint of the Functional Divisions of the Nervous System. By J. B. JOHNSTON. Four plates. Volume XV, Number 2, March, 1905. Observations on the Spinal Cord of the Emu and its Segmentation. IRVING HARDESTY. Four figures. By The Selection of Random Movements as a Factor in Phototaxis. By S. J. HOLMES. Notes on the Development of the Sympathetic Nervous System in the Common Toad. By WALTER C. JONES, M. D. Twelve Figures. Editorial: Concerning the Genetic Relations of Types of Action.-The Basis for Taxis and Certain Other Terms in the Behavior of Infusoria.-The Problem of Instinct. A Review of Some Recent Literature on the Chemistry of the Central Nervous System. By ISADOR H. CORIAT. Literary Notices. Volume XV, Number 1, January, 1905. On the Areas of the Axis Cylinder and Medullary Sheath as seen in Cross Sections of the Spinal Nerves of Vertebrates. By HENRY H. DONALDSON and G. W. HOKE. One figure. On the Number and Relations of the Ganglion Cells and Medullated Nerve Fibers in the Spinal Nerves of Frogs of Different Ages. By IRVING HARDESTY, Editorial: Psychology and Neurology.-The International Commission on Brain Research. Literary Notices. SEP 2 1905 Comparative Neurology and Psychology Volume XV 1905 Number 5 A STUDY OF THE FUNCTIONS OF DIFFERENT PARTS OF THE FROG'S BRAIN. By WILHELM LOESER, M.D. (From the Physiological Laboratory of the University of Kansas.) As a contribution to the study of the comparative physiology of the brain, it seemed important to undertake a more detailed investigation of the functions of the different parts of the frog's brain than had hitherto been made. The work done by me under the supervision of Dr. IDA H. HYDE to whom I am under great obligations-can, at best, constitute only a small link, in the long and complex chain of comparative physiology. The experiments extended over a period of two and a half months, and the material operated on consisted of more than fifty frogs of the species Rana temporaria. I employed GOLTZ's method, i, e., that of excising various parts, or aggregations of parts, of the central nervous system, and observed the resulting phenomena, particularly the deficiency phenomena. Both uni- and bilaterial excisions were resorted to. The animals were anesthetized with ether until they would not readily turn over on the ventrum when put on the dorsum, but would respond only with convulsive jerks of the muscles of the limbs. For operations on the medulla the anesthesia was carried further to prevent movements during the operation After the frog had reached this stage of anæsthesia, it was tied with its ventrum upon the frog board. sponge moistened with ether and placed in front of the nares was sufficient to keep the animal in the desired stage of anesthesia A during the operation. The skin over the cranium of the frog was first washed with a weak solution of bichloride of mercury, which was immediately removed with sterilized cotton and then with 95% alcohol. The instruments and the hands of the operhad been previously sterilized with 5% carbolic acid, followed by 95% alcohol. An incision was made through the skin of the cranium, following the mid-dorsal line. The skin was held apart by a pair of weighted hooks, and an opening was made with a small trephine through the cranium over the part of the brain to be removed. Since the two occipital arteries take their course laterally, this opening was made as near as possible on the mid-dorsal line of the cranium. With a delicate pair of forceps small pieces of the cranial bones were carefully broken away to make the primary opening of sufficient size for the operation. Great care was taken not to injure the meninges and the vessels of the choroid plexus therein. A 1% solution of adrenelin was used with great success whenever injury to the choroid plexus, or even the internal carotid and branches caused profuse hemorrhage. A small pointed knife and a very fine needle were used for excising or burning the different parts. RINGER's solution was used to moisten the wound after the operation. No antiseptics were used in the wound, which was closed with sterilized silk sutures. The animals were kept isolated in moist moss, which was frequently changed. At first they were observed two or three times a day, but, after several days, once a day, and after seven to ten days, once every two days was sufficient. Most of the frogs were fed after the operation; a few-depending upon the nature of the operation-were soon able to catch flies. The observations were tabulated, dated, and later the post mortem findings were added. Two animals were used for each operation, and the reactions compared with one another and with the reactions of normal frogs. I seldom noted the immediate effects within one-half hour after the operation, since they were obscured by the effects of the ether. In some instances where it was quite evident that |