ism v. UEXKÜLL gives accounts of certain experiments which had to do with food taking and various forms of behavior which are apparently intelligent, and with the forms of reaction of one, two, three or four armed animals. The descriptions of the reactions, which cannot be summarized within the few sentences of this notice, are followed by a consideration of the structure of the animal in its relation to reaction. The mechanics of movement are discussed. In connection with an examination of the principles of action in the nervous system the author takes occasion to show that the nerve impulse always passes in the direction of the expanded muscle (p. 28). The paper is a valuable contribution to our knowledge of the workings of the nervous and muscular systems in this form. Considering the great possibilities of the kinematographic method for the investigation of reactions and their reproductions on paper or on a screen, it is surprising that it is not more widely used. Photo graphs taken at the rate of 20 to 30 per second make possible the careful analysis of movements which are too rapid for the naked eye to follow satisfactorily. Moreover, a series of photographs will often make clear at a glance what pages of description may fail to make intelligible. R. M. Y. L'Année Psychologique. Tenth year, 1904. Paris, Masson et Cie, Binet, A. The tenth issue of the Année contains the Bibliography for 1903 (about 3000 titles) and the annual abstracts of the more important works. The original memoirs include several of interest to our readers, notably the paper by LECAILLON, "La biologie et la psychologie d'un araignée" and ZWAARDEMAKER'S "Sur la sensibilité de l'oreille aux différentes hauteurs des sons." Besides these features, we have the announcement of systematic annual digests of cytology, anatomy, physiology, pathology, anthropology and a number of other collateral fields, each by a specialist, which promise to be of great value. Twelve such digests are given in this issue. Attention should be called to the fact that the publisher of the Année has been changed since the last issue. C. J. H. Smallwood, W. M. Notes on the Natural History of Some of the Nudibranchs. Bulletin of Syracuse University, Series IV, No. 1, pp. 14-17, Oct. 1, 1904. Data on the copulation and eggs. C. J. H. 1. The Usual Movements; Spiral Swimming, p. 443. 2. Modification of the Movements under Stimulation; Reaction Types, p. 450. 3. The Avoiding Reaction, p. 450. 4. The Avoiding Reaction as a Factor in Be- A. Reactions Produced through the "Avoiding Reaction.” I. Reactions to Water-Currents; Rheotaxis, p. 468. 2. Part played by the Action System, p. 484. Peculiarity of the Reaction to Elec- tric Current, p. 488. Cause of Backward Swimming in Strong Currents, p. 494. Re- lation between Contact Reaction and Re- action to Electric Current, p. 496. Irreg- ularities of Reaction to the Electric Cur- rent, p. 503. Reaction of Paramecia to Since Paramecium is usually taken as a type for the study of unicellular animals, it is desirable to have its reactions to stimuli as fully known as possible. In attempting to put together the results of numerous investigations made during the last fifteen years on the behavior of this animal, I have found that there are still a number of reactions which have not been described, or have been described incorrectly, and that certain general relations running through the behavior have never been brought out. The present paper attempts to fill, so far as possible, these gaps in our knowledge, supplementing and unifying previous accounts of the behavior of Paramecium. The writer tries to point out omissions or errors in his own previous work with the same impartiality as in the works of others. The chief subjects dealt with are, in the first place, what we may call the action system of Paramecium; in the second place, the fundamental character of the stimulations to which the animal responds. In the third place an account is given of certain imperfectly or incorrectly known reactions, with particular reference to their relation to the "action system" of Paramecium. The chief reactions thus taken up are "rheotaxis," "geotaxis" and "electrotaxis." Methods.-A word should be said here as to certain methods of work. Throughout the following paper accounts are given of the direction of the effective beat of the cilia. This was determined in every case by mingling finely ground India ink with the water containing the Paramecia, thus observing the direction of the currents caused by the cilia. By using such a method one is not reduced to conjecture as to the really effective direction of the ciliary beat, as has been the case in certain papers on this subject, but this effective direction is determined immediately by observation. I have supplemented this method by observing the cilia of animals partly confined in a gelatin solution, in the usual way, and of animals partly stupefied with chloretone. These methods gave especially good results when combined with the use of India ink, to show the currents. Owing to its fineness, blackness, and absolute lack of chemical action, I have found the use of India ink (or Chi The nese ink) much preferable to that of carmine or indigo. ink is procured in sticks and rubbed up with water in the usual way. I. THE ACTION SYSTEM. By the behavior of an organism we mean essentially the regulation, by means of movement, of its relations to environmental conditions. The characteristic complex of movements by which the relations of Paramecium to its environment are determined may be called the "action system" of the organism. Most animals have certain peculiar methods of action, depending largely upon their structure-upon what VON UEXKÜLL (1903, p. 269) calls the "biologische Bauplan"-by which most of their behavior is brought about. These characteristic ways of acting are usually few in number and form a unified system, providing a definite reaction combination for any stimulus. The reaction systems of different animals vary as much as do their structures. Thus many different agents acting on a given animal may produce the same set of movements, while on the other hand the same agent acting on organisms of different "action systems" produces in each case different movements. The method of reaction then depends as much on the action system of the organism in question, as upon the physical or chemical action of the stimulus. The usual relation between the two factors may be expressed as follows: The action system supplies a limited number of methods of action, the character of the stimulus (including its localization) determines which of these methods shall be set in operation. In dealing with the action system of Paramecium, we have to consider, first, the usual movements and the environmental relations which they induce; second, the typical modifications of these movements (the reaction types), under the influence of stimulation. I. The Usual Movements; Spiral Swimming.—As is well known, Paramecium continually swerves toward the aboral side and revolves on its long axis as it swims through the water, so that its course is a spiral one (Fig. 3). The revolution, so far as I have observed, is always over to the left, when the anterior end is directed away from the observer. That is, the upper surface is continually passing to the observer's left (the lower surface of course to his right). Before using the stereoscopic binocular I supposed that the revolution was sometimes over to the right, sometimes over to the left (JENNINGS, 1899. p. 316). But observation of thousands of cases since this instrument was used has never shown a single exception to the revolution over to the left. I have repeatedly known observers working with the usual monocular microscope to assert that part of the Paramecia in a given culture were revolving over to the right, but on examination with the stereoscopic binocular they invariably became convinced that there was no exception to the revolution over to the left. The appearances shown by the monocular microscope are very deceptive in such phenomena, and I do not believe that observations with it even by practiced observers are reliable on this particular point. The revolution is still over to the left when the animals are swimming backward. This is contrary to the statement made in the second of my "Studies" (JENNINGS, 1899, p. 316), when I was working with the monocular microscope. But the binocular leaves no doubt upon this point. When the forward movement is reversed, the direction of rotation is not reversed. The oral groove of Paramecium always passes, if the oral side is down and the anterior end away from the observer, from the right behind to the left in front (as represented in BÜTSCHLI, 1889, Pl. 63, Fig. 1a). Many observers have reported Paramecia in which the direction of the groove is "reversed," running from the middle obliquely to the right instead of to the left. There is no general agreement as to the designation of the direction of a spiral. The above method seems most convenient for free swimming organisms, since it gives the results of immediate observation, and other methods of desig nation usually have to be translated, for practical purposes, into this one. If we used the method of designation proposed by NÆGELI (1860), the spiral of Paramecium rises from south to west. If we designate the direction of rotation by the method used in spiral cleavage, imagining a small observer situated in the long axis of Paramecium with head toward the anterior end (Kofoid, 1894, p. 180), then we must say that the rotation is to the right. |