THE LOCOMOTION OF LIMAX : II. VERTICAL ASCENSION WITH ADDED LOADS.

In Limax the lifting of additional loads during vertical ascension does not alter the law of linear proportionality between speed and frequency of pedal waves, or that between speed and dimensions of the single waves; for equal velocities of progression these quantities are the same, regardless of the mass lifted. The pedal organ of the slug, although under the control of central impulses, is thus essentially an independent effector.     

THE RELATION BETWEEN TEMPERATURE AND THE PEDAL RHYTHM OF BALANUS

1. The relation of temperature to the pedal rhythm of Balanus balanoides L. has been studied under otherwise constant conditions. 2. The frequency of movement increases with temperature, showing three groups of thermal increments and three critical temperatures. Five animals yielded µ = 5,700 above 14.5° C. and 12,100 below; 3 gave µ = 7,800 above 9.3° and 22,500 below; while 9 showed µ = 9,500 above 8.1° and 22,100 below. 3. The upper critical temperatures, above which different effects appeared in different animals were 23.4°, 26.0°, and 27.0°. Above 27.0° none of the valves remained open. 4. Excepting the values 5,700 and 9,500, the increments are similar to those previously found to be associated with respiratory and with neuromuscular activities. 5. Dilution of the sea water with from 3 to 4 per cent fresh water decreases the rate without altering the increments. More than 4 per cent dilution causes irregularity.     

DYNAMICS OF NERVE CELLS : I. THE TEMPERATURE COEFFICIENT OF THE NEUROGENIC RHYTHM OF THE HEART OF LIMULUS POLYPHEMUS.

In the case of the heart of Limulus polyphemus the same magnitude and variation of the temperature coefficient (Q ₁₀) is obtained from the whole heart as from the ganglion alone. From the magnitude of the temperature coefficients and their variation with changes of temperature we may conclude that the rate of the heart beat is determined by alteration of chemical processes in the ganglion cells.     

THE TEMPERATURE COEFFICIENT OF PHOTOSYNTHESIS

The temperature coefficient of photosynthesis in Ulva (between 17° and 27°C.) is 1.81. This may be explained by assuming that the process involves a light reaction with a low coefficient followed by an ordinary reaction with a high coefficient.     

THE TEMPERATURE COEFFICIENT OF PHAGOCYTOSIS

1. The experiments of Madsen and Watabiki on the effect of temperature on the phagocytosis of bacteria are discussed and a new analysis of their curves is given, showing that the rate of phagocytosis is very nearly a logarithmic function of the temperature from 0° to 35°C.; i.e., Q ₁₀ is constant over that range and is equal to 2.0. 2. New experiments are reported on the effect of temperature on the phagocytosis of quartz and carbon particles of uniform sizes, showing a marked increase in the temperature coefficient below 30°C.     

THE TEMPERATURE COEFFICIENT OF THE UREA DENATURATION OF EGG ALBUMIN

Evidence is brought forward to show that at concentrations of urea high enough to split the egg albumin molecule the solubility changes produced by urea are profoundly modified. The degree of precipitation after dialysis is the net result of two changes produced by the urea: the first, normally spoken of as denaturation, which makes the protein insoluble in dilute solution and the second, a splitting of the molecule which makes it soluble. These two reactions may proceed independently and simultaneously or the second reaction may follow the first, taking place in the denatured molecule only. In view of the decrease in the opalescence with time, the latter process is more probable. Both of these reactions have positive temperature coefficients, but as the concentration of urea increases the second reaction is more affected by increase in temperature than the first, and consequently the resulting opalescence decreases rather than increases with temperature. This accounts for and explains reports of negative temperature coefficients of denaturation, when denaturation is measured by the amount of insoluble material found on dilution. The occurrence of these two reactions, one leading to an increase and the other to a decrease in the amount of insoluble protein, should be taken into account when denaturation changes in egg albumin with urea are studied.     

FEEDING ACTIVITY OF LIMAX VALENTIANUS FERUSSAC: NOCTURNAL RHYTHM AND ALIMENTARY COMPETITION

Feeding activity of the slug Limax valentianus Férus-sacthroughout a 24-hour period began with the decrease in light.Feeding began 41 minutes after the start of locomotor activityand showed a maximum level in the beginning of the night L.valentianus had two to five meals each night, each meal lasting8.5 to 14 minutes. The overcrowding of the slugs induced a shorterduration of individual feeding periods and acts of aggressionduring meals. ^*Present address: Centre de Neurochimie, Laboratoire de neurobiologiemolécuiaire des interactions cellulaires. 5 rue BlaisePascal, 67084 Strasbourg, France (Received 7 July 1996; accepted 21 April 1997)     

PHOTOTROPIC CIRCUS MOVEMENTS OF LIMAX AS AFFECTED BY TEMPERATURE

1. The theory of animal phototropism requires for particular instances a knowledge of the action of light as exerted through each of two bilaterally located receptors functioning singly. The measurement of "circus movements" which this involves must be concerned with such aspects of the reaction as are demonstrably dependent upon the effect of light. 2. The negatively phototropic slug Limax maximus exhibits very definite and continuous circus movement under vertical illumination when one eye-tentacle has been removed. The amplitude of the circling movement, measured in degrees deflection per cm. of path as an index of maintained differential tonus, is intimately related to the concurrent velocity of creeping. Analysis of the orienting mechanism is facilitated by the fact that in gasteropods such as Limax the animal creeps by means of the pedal organ, but orients (turns) by a totally distinct set of muscles in the dorsal and lateral regions of the body wall. 3. The expression of the phototropic orienting tendency, with illumination constant, is greatly influenced by the temperature. Above a zone centering at 15°, the amplitude of turning (degrees per cm. of path) is determined by the temperature in accurate agreement with Arrhenius'' equation for chemical reaction velocity, with the critical increment µ = 16,820; and the rate of creeping is progressively less as the temperature rises, µ for its reciprocal being 10,900. Below 15°, the velocity of creeping becomes less the the lower the temperature, µ being again 16,800; while the amplitude of orientation is limited merely by the velocity of creeping, its reciprocal being directly proportional thereto. 4. Measurements of Limax circus movements in terms of turning deflection as function of light intensity must therefore be carried out at a temperature well above 15°. 5. The analysis provides a gross physical model of how an end-result may be influenced by temperature according to the effect of temperature upon each of several interconnected processes when the "temperature vs. effect" curves for these processes dynamically intersect. 6. It is pointed out that a certain type of unpredictability (quantative variability) in animal behavior under "normal" natural conditions probably results from dynamic equilibrium there obtaining between diverse mechanisms competing for effector control (in the present case, the creeping mechanism and that for turning, in the range 14–16°C.). It follows that the unraveling of the elements of conduct necessitates experimentation under diverse abnormal conditions favoring individual mechanism of response.     

THE PHOTOTROPIC EXCITATION OF LIMAX

The photic orientation of Limax creeping geotropically upon a vertical plate is such that the phototropic vector determining the angular deflection β from the vertical path is proportional to log I. This is proved by the fact that with horizontal illumination tan β is directly proportional to log I; with non-horizontal light rays from a small source the ratio See PDF for Equation is directly proportional to log I (where A = the angle between light rays and the path of orientation), the vector diagram of the field of excitation being in this case not a right-angled triangle.     

THE ANTIPROTEOLYTIC ACTIVITY OF SERUM : I. THE NATURE AND EXPERIMENTAL VARIATION OF THE ANTIPROTEOLYTIC ACTIVITY OF SERUM

1. An equation is derived for the calculation of a constant which, experimental results indicate, may be a more reliable index of the antiproteolytic activity of serum than those equations hitherto used. 2. (a) Intramuscular administration of trypsin resulted in a slow rise in the antiproteolytic activity of the serum, followed by a lesser decline. (b) Intravenous administration resulted in no appreciable variation. (c) Oral administration resulted in a rapid rise, which was sustained during the period of administration. (d) Intramuscular, intravenous, or oral administration of denatured trypsin resulted in no appreciable variation. (e) The extent of the local necrosis following subcutaneous injection of trypsin varied inversely with the antiproteolytic activity of the serum. 3. The experimental results indicate that the products of protein hydrolysis in the intestine and parenterally are an important factor in the antiproteolytic activity of the serum. They also indicate that antibodies to trypsin are not an important factor in the antiproteolytic activity of the serum.     

THE TEMPERATURE COEFFICIENT OF INACTIVATION OF CRYSTALLINE PEPSIN BY ULTRA-VIOLET RADIATION

Determinations of the temperature coefficient of inactivation of pure crystalline pepsin solutions by ultra-violet irradiation give values very close to unity (1.02).     

THE R?LE OF THE ACTIVITY COEFFICIENT OF THE HYDROGEN ION IN THE HYDROLYSIS OF GELATIN

1. The hydrolysis of gelatin at a constant hydrogen ion concentration follows the course of a monomolecular reaction for about one-third of the reaction. 2. If the hydrogen ion concentration is not kept constant the amount of hydrolysis in certain ranges of acidity is proportional to the square root of the time (Schütz''s rule). 3. The velocity of hydrolysis in strongly acid solution (pH less than 2.0) is directly proportional to the hydrogen ion concentration as determined by the hydrogen electrode i.e., the "activity;" it is not proportional to the hydrogen ion concentration as determined by the conductivity ratio. 4. The addition of neutral salts increases the velocity of hydrolysis and the hydrogen ion concentration (as determined by the hydrogen electrode) to approximately the same extent. 5. The velocity in strongly alkaline solutions (pH greater than 10) is directly proportional to the hydroxyl ion concentration. 6. Between pH 2.0 and pH 10.0 the rate of hydrolysis is approximately constant and very much greater than would be calculated from the hydrogen and hydroxyl ion concentration. This may be roughly accounted for by the assumption that the uncombined gelatin hydrolyzes much more rapidly than the gelatin salt.     

THE EFFECT OF TEMPERATURE ON THE MECHANICAL ACTIVITY OF THE GILLS OF THE OYSTER (OSTREA VIRGINICA Gm.)

1. The method is described whereby the rate of flow produced by the gills of the oyster can be measured accurately. 2. The rate of doing work in maintaining a constant current along the glass tube can be expressed by the formula W = 2πlµ S ², where W = ergs/sec., l = length of the tube, µ = viscosity in poises, and S = speed at the axis of the tube. 3. The relationship between the rate of doing work and the temperature cannot be described by the equation of Arrhenius. 4. The optimum temperature for the mechanical activity of the gills lies between 25° and 30°C. Below 5° no current is produced, though the cilia are beating. Ciliary motion stops entirely at the freezing temperature of sea water. 5. The factors responsible for the production of current are discussed. The study of the relations between the variability of the rate of flow and the temperature shows that between 15° and 25°C. the absolute variability remains constant and increases considerably above 25° and below 15°. The rôle of the coordination in the production of current is discussed, and the conclusion is reached that coordination is affected by the changes in temperature.     

温度对家白蚁的生存和活动的影响

家白蚁 Coptotermes formosanus Shiraki 的生存、行为和取食活动与温度密切相关。探索温度对家白蚁的生存以及行为、取食诸活动的影响,对于研究其生态学和防治学,都具有重要意义。广东省昆虫研究所对此曾进行过许多有益的研究,并作过一些有价值的报道。笔者于1986—1987年,对此问题作了系统的试验,得到一些新的结果,报道如下。     

干燥温度对苏云金芽孢杆菌伴孢晶体的结构及杀虫活性的影响

用电镜、电泳、生物鉴定等方法,研究了干燥温度对苏云金芽孢杆菌库斯塔克变种苏云金芽孢杆菌库斯塔克变种（ＢａｃｉｌｌｕｓｔｈｕｒｉｎＦｉｅｎｓｉｓｖａｒ．Ｋｕｒｓｔａｋｉ）ＨＤ－１的伴孢晶体的结构及杀虫活性的影响。结果表明,０℃冷冻干燥的效果最好,对伴抱晶体的电泳图谱、形态、结构及杀虫活性均无影响;７５Ｃ以下干燥对伴孢晶体的形态和结构略有影响,但对电泳图谱和杀虫活性尚无影响,生产上可以采用。但在７５℃下超过５小时的长时间干燥,对晶体蛋白的空间结构和杀虫活性也有影响,因此,要适当控制干燥时间。８０