tropical countries. Dr. P. Manson has traced out the life history of certain microbic forms which are present in the blood of an animal suffering from malaria. These bodies are either crescent shaped or flagellated, the latter form being a constant feature of malarial blood, although it is not present till ten or fifteen minutes after the blood is drawn, and seems to be formed from the break up of the crescentiform bodies. These latter bodies appear to resist the action of phagocytic cells, and to persist in the blood unchanged for weeks, not undergoing any development while in the body. Dr. Manson suggests that a stage in their life history may be passed in a suctorial insect such as a mosquito. The exact importance of the "cell" as a biological unit has for some time been a subject for sharp controversy. The original idea that every organic structure is made up of a number of cells, each consisting of a mass of protoplasm bounded by a more or less definite cell wall, has been shown not to be true, the protoplasm of a plant being continuous throughout the organism, as has been shown by Gardiner and others. Similarly Mr. A. Sedgwick has pointed out that the so-called mesenchyma tissue of the embryo of the Elasmobranch fishes is often described as a layer of branched cells lying between the ectoderm and endoderm. There are, however, no separate cells, but only a network of pale protoplasmic substance holding nuclei at the junctions of the net. The tissue is, in fact, continuous with the ectoderm and endoderm, the primary layers of which are simply parts of this reticulum in which the meshes are closer and the nuclei more numerous and arranged in layers. In effect Mr. Sedgwick argues that the development of either nervous or muscular or connective tissue takes place out of and as part of a continuous protoplasmic mass. On the other hand, Mr. G. C. Bourne points out that the cell theory has still plenty of support. Thus the ovum in Unio or Nereis shows a clear subdivision into separate protoplasmic corpuscles. As the nucleus is the most important part of a cell, he would make this nucleus the basis of his definition and describe a cell as "a mass of protoplasm containing a specialised element nuclein." Cells could then be divided into those of discrete protoplasm, or not united with any other, and concrescent, and this latter would be again sub-divided into continuous, where the nuclei are separate but the protoplasm is fused into one mass, and conjoint, where the masses are united to one another by fine bonds or prolongations of protoplasm. A new view as to the cause of coagulation of blood has been put forward by L. Lilienfeld, who ascribes this effect to the influence of a nucleo-albuminous substance on fibrinogen. The so-called fibrin ferment he considers a product and not a cause of coagulation. In this connection the observations lately made by Mr. Ramsden deserve notice. It appears that if solutions of certain proteid bodies be taken clots or flocculi can be obtained merely by mechanical agitation even when substances are used which, like alkali albumen, are not precipitated by heat. Even fibrinogen when extracted from the blood yields a precipitate by this method. Important researches on secretion have been published during the year. Thus Dr. Weymouth Reed has found that the cells of the skin of the frog take no active secretory part in the elimination of carbonic acid gas, which forms an

But of more general

important respiratory function of the skin. interest are the experiments of Pawlow on the conditions determining the secretion of gastric juice by the stomach. He has determined that in the dog no active secretion of gastric juice is produced by the mastication of starchy foods nor by the passage of such food into the stomach. If, however, meat be taken into the mouth and chewed a secretion of gastric juice rapidly takes place, even when the meat is prevented from entering the stomach. It thus appears that the secretion is dependent not on any actual stimulation of the coats of the stomach by the presence of food, but is a reflex action connected in some unexplained way with a discriminative action of the palate and glands of the mouth. From the observations of Starling and Leather it would appear probable that the physical laws of transpiration and osmosis are sufficient to account for the phenomena of the absorption of liquids by the serous surfaces of the body without calling in the aid of any selective vital action. The causes of muscular fatigue have been studied by Professor Stockvis of Amsterdam, who finds that a muscle becomes exhausted, not from want of available nutritive material, but from fatigue of the nerve centres. It is therefore rest rather than food which is primarily necessary to enable a muscle to recover its energy, the nerve centre becoming tired long before the store of material at the disposal of the muscle is used up. The effect of gravity upon the circulation of the blood has of course been long recognised. Some interesting results have, however, been obtained in this respect by Dr. Hill. Thus the restriction of the flow of blood to the abdominal viscera increases the vascularity of the brain and muscles of the trunk. Even slight changes in position, such as turning from lying on the side to lying on the back, cause a marked alteration in the arterial pressure. The time taken for a blood corpuscle to make a circuit of the body has been redetermined by Dr. A. Stuart of Sydney as not more than fifteen to twenty seconds. The definition of certain skin areas in their relation to deep-seated parts of the body has been carried out from the experimental side by Sherrington, Langley, and others, and from the clinical side by Head. The connection between the sensory nerves supplying certain parts of the skin and those which belong to internal organs is the cause of the occurrence of sympathetic or referred pain, such, for example, as the pain between the shoulder blades experienced in liver disease. Dr. G. Mann has compared the brain areas in certain rodents, carnivora, and insectivora, tracing the particular parts of the brain which, when electrically stimulated, produce the same series of bodily movements, and has thus added much valuable material for the better solving of problems in cerebral surgery. In the development of the permanent teeth Dr. W. Dietlein finds from a study of over 7,000 cases that the canine teeth of girls appear on an average nine months earlier than those of boys, and that a similar sex difference is noticeable in the anthropoid apes. With regard to the gradual degeneration of the teeth, he finds that in an average town population the upper lateral incisor is lost or defective in three per cent. of townsfolk, though the percentage is much less among those born and brought up in the country.

H

The question of the evolution of the various senses from a general touch sensation has always been one to attract biologists. Thus Dr. W. A. Nagel has found that the whole surface of Amphioxus is responsible to sudden illumination, and that this sensibility to rapid change from light to darkness is shared by many other animals quite apart from the possession of special sight organs. Mr. Child has traced an auditory organ in the swollen basal joint of the antennæ in certain gnats and midgets. A similar organ he finds exists in a more rudimentary form in other genera of dipterous insects and in certain members of the Lepidoptera, Hymenoptera and Coleoptera. He was, however, unable to detect its presence in any orthopterous insect. In the gnat this sense organ is specially developed in the male, and Dr. Hurst and Mr. Child conclude that the hairs on the shaft of the antennæ of the male vibrate to the same note as is produced by the membranes connected with the thoracic spiracles of the female. In the small water bug Corixa this note is produced by drawing the front feet across the face, and thus causing vibrations in a series of extremely fine peg-like processes with which these feet are furnished.

Another interesting discovery in the insect world has been made by Mr. O. H. Latter, who finds that many moths assist their emergence from the cocoon by exuding an alkaline liquid which softens the anterior end of the cocoon substance. An analysis of the fluid secreted by Dicranura vinula showed the presence of 14 per cent. of caustic potash. Mr. J. J. Lister has shown that in a great number of cases species of Foraminifera are dimorphic. These dimorphic forms do not appear to be sexually different, but are probably members of a cycle of generations. The two main varieties of form he classes as microspheric and megalospheric. When in the life history of the species a parent microspheric form becomes divided into young, these all belong to the megalospheric form; but the actual converse of this relationship does not appear to have been as yet satisfactorily worked out.

The discussion of dimorphism or polymorphism has also been raised in another fashion by Forel, who gives seven possible forms, under which may be classed the various intermediate stages in ants. These forms he would ascribe to the action of "germinal variation." Mention must also be made of the elaborate work of Mr. F. E. Beddard on the worms, a subject he has made peculiarly his own.

Mr. J. G. Kerr has made a careful study of the anatomy of Nautilus pompilius, and pointed out many analogies between its structure and that of Chiton. A number of experiments on the effect of cold on seeds have been made by M. C. de Candolle. He finds that in the case of wheat and oats the temperature may be lowered time after time to -30°C. without affecting the subsequent germination of the seed. In the case of the mimosa or lobelia this temperature was, however, fatal. It would appear from these experiments that the protoplasm of seeds passes into a more or less thorough state of suspended animation from which it is only aroused when placed in suitable conditions of moisture and temperature. The phrase to see or hear a plant growing will now acquire a more literal meaning, for Mr. A. Möller noticed in a Brazilian fungus Dictyophora phalloidia that the rate of growth was

from two to five millimetres per minute; so rapid was the expansion of tissue that a slight crackling sound could be heard. The necessity of studying foliage as well as flowers in plant determination has been well illustrated by Mr. Thistleton Dyer, who has pointed out that whereas the flower of the cultivated Cineraria is quite unlike that of the wild Cineraria cruenta of the Canaries, yet the foliage and anatomical form of the two plants are alike. The fixation of nitrogen in the soil has been ascribed by M. S. Winogradsky to the action of Closterium Pasteurianum, which he considers is the only microbe capable of working up the free nitrogen into an insoluble organic product. Among the causes which have produced the present geographical distribution of marine flora and fauna, Mr. R. Vallentin places as most important the action of floating sea-weed. By this means many hydroids and bryozoans could be carried from place to place. In connection with this it may be noted that Mr. W. Faxon finds that the littoral zone is richer in representatives of archaic forms than the deeper sea.

GEOGRAPHY.

There has been no falling off during the past year in the interest felt by geographers in Polar exploration, but this interest is being directed to the Antarctic rather than to the Arctic regions. The voyage of the Antarctic under Captain C. A. Larsen has directed attention to the South Polar Continent, which has not been visited since Sir James Ross' expedition of fifty years ago. Mr. E. Borchgrevink made a number of observations on the character of the rocks, the temperature of the air and water, and the formation of the ice, which will be of great value to future explorers. The course of Arctic discovery has been again marked by misfortune. Lieutenant Peary and the remains of his company were brought back from Inglefield Gulf by the sealing steamer Kite. After wintering in Whale Sound, Peary had endeavoured once more to move northward, and complete his survey of the north coast of Greenland, but owing to the depth of snow which had fallen the caches of food which had been prepared in the previous year could not be found, and the party had to return. They suffered dreadful privations on this journey, the last forty-six hours' travelling having to be accomplished without any food amid all the rigours of the Greenland climate. According to Professor Salisbury, who accompanied the Kite in its voyage from Newfoundland, the snowline in Greenland is lower on the American than on the European side. The Windward, which conveyed the members of the Jackson-Harmsworth expedition to their base of operations in Franz Josef Land, returned early in September to Vardö after having taken sixty-five days to force its way through the ice. The Windward was permanently frozen in within five days after its arrival on September 7, 1894. An exploration of the Greenland Sea has been in progress under Captain Wandet of the Danish navy, and a Russian explorer, M. Tchelnirscheff, has been at work in Nova Zembla. The country to the north-west of the Hudson Bay, beginning at Reindeer Lake, has been visited by Mr. J. Burr Tyrrell. The new ground covered was chiefly in the direction of the Ice River, but many obser

vations of interest were made in the earlier portion of the route between the Saskatchewan and the Reindeer River. Dr. R. Bell has reported the existence of a large river in the country between 74° and 80° W. longitude and 48° to 51° 30′′ N. latitude situated in the northern part of the province of Quebec or of North-west Labrador. This river he reports flows for 250 miles through forests. Exploration in Africa is not often now carried out by mere enthusiasm for geographical knowledge. The struggle between European nations for the hinterland of their respective possessions is gradually leading to a more complete acquaintance with the interior of the continent. Among the most interesting of these expeditions was that of Captain T. D. Lugard to Borgu. Leaving Akassa on August 28 he reached Jebba, 550 miles up the river, on September 9, and by the 27th had arrived at Bussa, 200 miles higher. A treaty was made with the local chiefs of Kishi on the northern frontier of Yorubaland. On November 5, Captain Lugard arrived at Nikki, being the first European to set foot in that town, and was followed later in the same month by a French expedition under Captain Delcœur. Borgu is described as an undulating fertile country inhabited by plundering bands. The natives, who call themselves Pariba, were not conquered by the Fula invasion which overran so much of Central Africa, nor were they beaten by Behanzin and his Amazons. Captain Lugard speaks in very high terms of the straightforward behaviour of the first Borgu chief he met, named Kiama. Owing to the hostility of certain tribes he was compelled to return by a roundabout route to Saki in Yorubaland, and with the aid of Captain Bower delimited the territory of Ilorin. Captain Delcœur in a second expedition from Dahomey succeeded in reaching Sai on the Upper Niger and in descending the river to Bussa, a feat which has not been accomplished since the days of Mungo Park. The representatives of Germany have not been behindhand in the race. Lieutenant van Carnap starting from Togoland managed to reach the capital of the kingdom of Surma, which had been described by Barth though not actually visited. This expedition, like its French predecessor, made for Sai and then proceeded along the river to Somba. The heat at Sai is described as very trying, a shade temperature of 107° being recorded in the month of February. These various journeys have practically completed the exploration of the main stream of the river Niger from source to mouth. Next in interest to the work done in the Niger country is that achieved by Dr. Donaldson Smith on the other side of the continent. Dr. D. Smith has been the first to reach Lake Rudolf from the north after an adventurous journey through the disturbed country lying between Abyssinia and Somaliland. Among the collection of birds which he has brought home are no less than twenty-two species previously undescribed. Mr. G. F. Scott Elliott has published his observations made on his journeys between the Victoria Nyanza and the other great lakes of Central Africa. He finds traces of former glacial action, not only on the slopes of Ruwenzori, but even in the valleys. In the north of Africa Mr. H. S. Cowper has completed a journey to Tarhuna and Gharian in Tripoli, undertaken for the purpose of studying the megalithic ruins mentioned by Barth as existing in those localities. The Sahara district lying im