A note on the physiological arrangement of tissuesMorales, M. F.;Smith, R. E.
doi: 10.1007/BF02478452pmid: N/A
Abstract Presented are the kinetics of uptake of an inert solute by tissues arranged in series, distinct parallel and competitive parallel, with respect to the circulation. The uptake in all cases can be described by a series of exponentials, but the number of these terms and the character of the constants is specific for each arrangement. This fact can be of value in deducing tissue arrangement from uptake data.
A theory of photosensitivity of some lower animalsRunge, Richard
doi: 10.1007/BF02478454pmid: N/A
Abstract The two-factor nerve excitation theory is applied to the photoreactions of some lower animals along with the assumption that the threshold itself varies under the action of light, thus behaving formally like a third factor. The dependence of the reaction time upon the intensity of the stimulus is derived and is shown to follow the Bunsen-Roscoe law. The dependence of reaction time upon the time of exposure to light of a fixed intensity is derived and analyzed. The effect of dark adaptation upon the reaction time is analyzed quantitatively. Light adaptation and the effects of termination of exposure after light adaptation are discussed from the standpoint of this theory and the theory is found to be in agreement with observations.
Outline of a mathematical approach to the cancer problemRashevsky, N.
doi: 10.1007/BF02478455pmid: N/A
Abstract The fact that the growth of every organism, as it develops through cell multiplication from the ovum, eventually ceases, makes plausible the hypothesis that each cell of an organism exerts some kind of inhibitory influence upon the growth and multiplication of every other cell through the medium of some factorj. Each cell, however, is considered to possess an amount of a “growth factor”g, the activity of which is inhibited byj. In the course of development, most cells differentiate. A number of them remains relatively undifferentiated, and those are used for repairs of natural tear and wear as well as for healing of wounds. With age either the number of those cells or their “potency” decreases, which accounts for a general decrease in the speed of wound healing. Due to statistical fluctuations, the amount of theg is not uniformly distributed amongst the cells. Some of them have accidentally a greater amount than others. As the number or potency of the undifferentiated cells decreases with age, so does their inhibitory influence upon other cells. Therefore, those cells which do have an accidental dental excess ofg-factor will begin to grow and multiply, producing neoplasms. Putting the above assumptions into mathematical form, it is possible to derive a relation which gives theprobability of cancer incidence as a function of age. The theoretical relation is compared to the rather inadequate empirical data and found in agreement with them. A relation for the speed of wound healing as a function of age is also derived, and also found in general agreement with the rather scant data. Several other conclusions are discussed and possibilities of their practical applications pointed out.
A heterarchy of values determined by the topology of nervous netsMcCulloch, Warren S.
doi: 10.1007/BF02478457pmid: N/A
Abstract Because of the dromic character of purposive activities, the closed circuits sustaining them and their interaction can be treated topologically. It is found that to the value anomaly, whenA is preferred toB,B toC, butC toA, there corresponds a diadrome, or circularity in the net which is not the path of any drome and which cannot be mapped without a diallel on a surface sufficient to map the dromes. Thus the apparent inconsistency of preference is shown to indicate consistency of an order too high to permit construction of a scale of values, but submitting to finite topological analysis based on the finite number of nervous cells and their possible connections.