hands of anatomists, were similarly reproduced in the three brains. Illustrations were given.

The Bimeric Distribution of the Spinal Nerves in Elasmobranchii and Urodela, by CHARLES R. BARDEEN. In those vertebrates in which a definite metameric segmentation is maintained in the body wall, both the cutaneous and the motor nerves of each segment reach their distribution through the myoseptum and supply structures both cephalad and caudad to their septum. Occasionally a single motor nerve fiber may be seen dividing and sending one branch to the myotom anterior to the septum and the other to the myotom posterior. Attention is called to the difficulty of reconciling these facts with a strict adherence to an extreme form of the neuro-muscular theory such as is maintained by some morphologists.

A Description of the Gross Anatomy of the Adult Human Brain, by BERN BUDD GALLAUDET. The description was confined to the thalmus and was based on forty adult brains.

On the program of the Eastern Branch of the American Society of Zoologists, meeting at Philadelphia, the following titles, among others, were announced:

The Physiology of the Lateral Line Organs in Fishes, by G. H. PARKER. To appear in abstract in this Journal and in full in the Bulletin of the U. S. Fish Commission.

A Pair of Giant Nerve Cells of the Squid, by LEONARD W. WIL

LIAMS.

The Nervous System of Lamellibranchs, by GILMAN A. DREW. The Origin and Function of the Medullary Sheaths of Nerve Fibers, by PORTER E. SARGENT. To appear in full in this Journal.

The Relation of the Size of Nerve Elements and Their Constituent Parts to Structural and Functional Conditions, by PORTER E. SARGENT.

At the Philadelphia meeting of the American Physiological Society the following papers, of special interest to neurologists, were read:

The Survival of Irritability in Mammalian Nerves after Removal from the Body, by W. D. CUTTER and P. K. GILMAN. Making use of the fact noted by other observers that the mammalian nerve retains its irritability for some time after removal from the body, the authors attempted to determine the duration of this survival, the variations in irritability during the period of survival, and, lastly, the effect of prolonged anesthesia upon the phenomenon. Irritability was determined by measuring the action current of the nerve when

stimulated by a series of induction shocks. The experiments were made upon dogs, and the sciatics of both legs were taken for observation. One sciatic was removed as soon as the animal was anesthetized sufficiently for the operation. The nerve was placed at once in the moist chamber, and its action current was determined at intervals of half an hour, as long as a response could be obtained to stimulation. With the values of these action currents as ordinates, a curve was constructed, showing the duration and variations of irritability in the "unanesthetized nerve" during the period of observation. The other sciatic was left in the animal for a period of four to six hours, and during this time the animal was kept completely anaesthetized by morphia and ether. At the end of this period, there was a considerable fall in rectal temperature (30°-31° C.). The anaesthetized nerve was then removed, and galvanometric observations were made similar to those just described. The results obtained show that the nerve removed from the anesthetized (and cooled) animal survives for a longer period than that taken from the animal at the beginning of the period of anesthesia, the difference in time of survival being as much as four or five hours. A more marked difference, however, is that the "anesthetized" nerve exhibits throughout a much greater irritability. The curves obtained were irregular; but that for the "unanæsthetized" nerve shows a small increase in irritability occuring shortly after the excision, and soon followed by a steady decline to zero; while that for the "anesthetized" nerve exhibits, as its most marked feature, a large and sudden increase in irritability coming on some hours after the excision, and followed by a more rapid fall to zero.

The Condition of the Vaso-constrictor Neurones in "Shock," by W. T. PORTER and W. C. QUINBY. The normal fall of blood-pressure produced by stimuli of uniform intensity applied to the central end of the depressor nerve was measured in the rabbit and the cat. In the same animals the shock was then brought on, and the measurements repeated. The experiments make clear (1) that the normal percentage fall in blood-pressure may be obtained by stimulating the depressor nerve during shock; (2) if during shock the blood-pressure be raised to normal values by the injection of suprarenal extract or normal saline solution, and the depressor nerve be stimulated while the pressure is still high, the absolute fall in blood-pressure may be as great as it was in the same animal before shock began. Exhaustion of the vaso-constrictor neurones cannot therefore be the essential cause of the symptoms termed shock.

Demonstration of Rabbit's Nerves, Showing the Effect of Ligation

upon Vital Staining, by S. J. MELTZER.

A single ligation of a nerve

has no influence upon the staining of the nerve on either side of the ligature. When, however, two ligatures are applied, the section of the nerve between the ligatures remains free of color, while both ends are stained. This is the case, even if the section between the ligatures comprises nearly the entire length of the nerve.

The Effect of a Subcutaneous Injection of Adrenalin on the Eyes of Cats whose Sympathetic Nerve is Cut, or whose Superior Cervical Ganglion is Removed, by S. J. MELTZER. When the sympathetic is cut, a subcutaneous injection of adrenalin causes a retraction of the nictitant membrane, and no change is seen in the size of the pupil or the width of the palpebral fissure. When, however, the superior cervical ganglion is removed, an injection causes a strong dilatation of the pupil, a considerable widening of the palpebral fissure, and a retraction of the nictitant membrane.

The Delineation of the Motor Cortex in the Dog, by H. CUSHING. Demonstration of Expressive Motions in a Decerebrate animal, by R. S. WOODWORTH.

At the meeting of the American Philosophical Association at Princeton the paper, "An Establishment of Association in Hermit Crabs," by EDWARD G. SPAULDING, which we publish herewith, was read. There was one paper on comparative psychology read at the meeting of the American Psychological Association at St. Louis.

A Preliminary Paper on the Psychology of the English Sparrow, by JAMES P. PORTER. Experiments were made with the food box, with SMALL'S complex maze and in other ways to determine the method of approaching the food, to investigate the so-called senses of number and of direction and the color preferences.

A paper was read before the section of physics of the American Association at St. Louis, which is of some interest to physiologists, especially when taken in connection with the physiological experiments of NAGEL on the rate of diffusion of odors and savors in water.

Attention is

The Rate of Propogation of Smell, by JOHN ZELENY. drawn to the extreme slowness of diffusion of odors in air tubes where convection currents are avoided. The time required for the diffusion of odors is roughly proportioned to the square of the distance.

LITERARY NOTICES.

Animal Education.1

Under this title Dr. WATSON has published the results of a study of the white rat made for the purpose of correlating the psychical development with the growth of the nervous system. The work is naturally divided into three parts: (1) an experimental study of the psychical development; (2) an histological study of the central nervous system, for the purpose of tracing the development of medullation, and (3) a correlation of the psychical facts with the neurological facts.

Part I. The ability of the white rats at different ages to form simple associations was tested by various forms of the labyrinth method. The obtaining of food was employed as a motive. Usually the food was placed in a box and the animals were given a chance to get it by finding a hidden opening into the box, by opening a spring door, or by wending their way through a labyrinth. The observer watched the behavior of the animals, and recorded the time required for the accomplishment of a given act. The results of this psychological study include certain interesting points of difference between young and mature rats which cannot be better stated than in the words of the author: No form of problem which the adult rat is capable of solving presents insurmountable difficulties to the rat of twenty-three days of age. 2. a) The time of first success in solving problems conditioned chiefly upon physical activity is shorter for young rats than for adults. b) For the second solution of such a problem, adult rats do not require a longer time than young rats.

c) Problems not so conditioned upon physical activity are solved, even the first time, more quickly by adult than by young rats.

3. a) Young rats make many more useless movements than adult.

1 WATSON, JOHN B. Animal Education: An experimental study on the psychical development of the white rat, correlated with the growth of its nervous system. Chicago, The University of Chicago Press, 1903, 122 pp., 22 Figs., 3 Plates.

b) After once associating the various parts of a problem, adult rats make only the movements necessary to attain the desired end, while young rats-owing to their superabundant physical activity and lack of muscular control-continue to make useless movements long after adult rats have discarded them entirely.

c) There is a gradation in the number of useless movements made by rats at different ages. At thirty-five days of age, when physical activity appears to have reached its highest stage, the percentage of useless movements is largest. As the rats grow older this superabundant activity disappears, and in its place comes direction of activity.

Concerning the stages of memory the author writes:

1. Until the rat has reached the age of twelve days, life to it is simply a matter of pure instinct. Certain movements are made, but these movements are dependent upon the ready-made adjustments of neural and motor elements with which the rat begins life; intelligence plays little or no part.

2. At twelve days of age memory is present in a simple form.

3. From the twelfth to the twenty third day there is a gradual but rapid increase in the complexity of the memory processes until at the latter age psychical maturity is reached. Development after this age is analogous to the development that takes place in a child of ten years as he gradually becomes more and more mature.

Parts II and III. Having investigated the capacity of rats to learn simple associations, at different stages of development, the author proceeded to make a careful histological study of the changes which occur in the nervous system from birth to maturity in order that he might be able to correlate the psychical and neural conditions and definitely determine whether associations are dependent upon the medullation of nerve fibers. As a result of this work Dr. WATSON concludes: (1) that the "medullated fibers in the cortex of the rat are not a conditio sine qua non of the rat's forming and retaining definite associations, and (2) that the complexity of the psychical life increases much. more rapidly than does the medullation process in the cortex, psychical maturity being reached when approximately only one-fifth of the total number of fibers in the cortex are medullated."

Instead of speculating about the general significance of medullation the author very wisely confines himself to the discussion of his own particular facts. The experimental work is clear cut and decisive, and if one sometimes feels that fewer words might have sufficed and and space been saved by the condensation of results into tables, the excellent summaries more than compensate for the lengthiness of the descriptions. Dr. WATSON has done a valuable piece of work in a field which has been open thus far for the theorizing of neurologists and psychologists.

ROBERT YERKES.