It is sometimes said that lime acts as a poison on some plants and not on others, and sometimes that it is the physiological dryness of calcareous soils that is the important factor.
Notwithstanding the fact, however, that these cells are capable of acting as very efficient lenses the explanation given by Haberlandt has not been widely accepted and evidence both morphological and physiological has been brought forward against it.
All soils which are physically dry are also physiologically dry; and hence only the physiological dryness or wetness of soils need be considered in ecology.
(From Lankester, "Limulus an Arachnid.) of adaptation to the changed physiological conditions of respiration, and not of morphological significance, since a pair of renal excretory tubes of this nature is found in certain Amphipod Crustacea (Talorchestia, &c.) which have abandoned a purely aquatic life.
An absolutely imperceptible physiological difference arising as a variation may be of selective value, and it may carry with it correlated variations which appeal to the human eye but are of no selective value themselves.
It may be, however, that there is no special mechanism, but that this power is a particular differentiation of a physiological kind, existing in all vegetable protoplasm, or in that of certain cells.
In 1900 a high school for shipbuilding was founded, and in 1901 an institute for seamen's and tropical diseases, with a laboratory for their physiological study, was opened, and also the first public free library in the city.
The treatment is to empty the stomach by tube or by a non-depressant emetic. The physiological antidotes are atropine and digitalin or strophanthin, which should be injected subcutaneously in maximal doses.
By Fisher, Plant Geography upon a Physiological Basis (Oxford, 1903f 904).
Morphologically, the spiders are remarkable for the concentration and specialization of their structure, which is accompanied with high physiological efficiency.
Anatomy and the study of animal mechanism, animal physics and animal chemistry, all of which form part of a true zoology, were excluded from the usual definition of the word by the mere accident that the zoologist had his museum but not his garden of living specimens as the botanist had; 1 and, whilst the zoologist was thus deprived of the means of anatomical and physiological study - only later supplied by the method of preserving animal bodies in alcohol - the demands of medicine for a knowledge of the structure of the human animal brought into existence a separate and special study of human anatomy and physiology.
Ludwig, under whom he studied at Zurich, decided him to devote his attention to physiological chemistry, and therefore he went, after his graduation (18J4), to Heidelberg, where R.
Nine memoirs, entitled "Electro-Physiological Researches," were published in the Philosophical Transactions, 1845-1860.
This physiological wasting is termed senile atrophy.
Whether it was physiological or psychological didn't matter at this point.
The differentiation of the plants substance so indicated is, however, physiological only; there is no histological difference between the cells of these regions that can be associated with the several properties they possess.
Schimperl made a distinct advance when he distinguished between physical and physiological dryness or wetness of the soil.
With regard to the occurrence of plants, such as Juncus effusus, which possess xerophytic characters and yet live in situations which are not ordinarily of marked physiological dryness, it should be remembered that such habitats are liable to occasional physical drought; and a plant must eventually succumb if it is not adapted to the extreme conditions of its habitat.
However, until more is known of the exact chemical composition of naturalas contrasted with agriculturalsoils, and until more is known of the physiological effects of lime, it is impossible to decide the vexed question of the relation of limeloving and lime-shunning plants to the presence or absence of calcium carbonate in the soil.
Upon our knowledge of its minute structure or cytology, combined with a study of its physiological activities, depends the ultimate solution of all the important problems of nutrition.
Evolution means the gradual development of highly organized from lowly organized forms; that is, of forms in which the physiological division of labor is more complete, from those in which it is less complete; of forms possessing a variety of organs, from forms possessing but few.
The investigation of these may raise and solve interesting physiological problems, but throw no light on the facts and genetic relationship which a rational explanation of distribution requires.
From the point of view of the economy of the globe this classification by species is perhaps less important than that by mode of life and physiological character in accordance with environment.
He retired to Darmstadt, where he practised as a physician and contributed regularly to pathological and physiological magazines.
This method, which in process of time was dignified by the title of a Physiological Arrangement, was insisted upon with more or less pertinacity by the author throughout a long series of publications, some of them separate books, some of them contributed to the memoirs issued by many scientific bodies of various European countries, ceasing only at his death, which in July 1857 found him occupied upon a Conspectus, Generum Avium, that in consequence remains unfinished.
The views of Bonaparte were, it appears, also shared by an ornithological amateur of some distinction, John Hogg, who propounded a scheme which, as he subsequently stated (Zoologist, 1850, p. 2797), was founded strictly in accordance with them; but it would seem that, allowing his convictions to be warped by other considerations, he abandoned the original " physiological " basis of his system, so that this, when published in 1846 (Edinb.
Yet the idea of a " physiological " arrangement on the same kind of principle found another follower, or, as he thought, inventor, in Edward Newman, who in 1850 communicated N ewman.
Many other points of physiological optics are touched on, in general erroneously.
He had already acquired a considerable reputation in physiological research.
For the Heteronemertines arguments have been adduced to prove that here they have the physiological significance of a special respiratory apparatus for the central nervous tissue, which in all these forms is strongly charged with haemoglobin.
Colour and Constitution.-In this article a summary of the theories which have been promoted in order to connect the colour of organic compounds with their constitution will be given, and the reader is referred to the article Colour for the physical explanation of this property, and to Vision for the physiological and psychological bearings.
In Scorpio the completion of the horizontal plate by oblique flaps, so as to form an actual diaphragm shutting off the cavity of the prosoma from the rest of the body, possibly gives to the organs contained in the anterior chamber a physiological advantage in respect of the supply of arterial blood and its separation from the venous blood of the mesosoma.
William of Conches, a pupil of Bernard's, devoting himself to psychological and physiological questions, was of less importance for the specific logico-metaphysical problem.
Examples of physiological hypertrophy are found in the ovaries, uterus and mammary glands, where there is an increased functional activity required at the period of gestation.
Their physiological activities gradually fail owing to the constructive processes having become so exhausted from long use that the destructive ones are able to overtake them.
According to our present knowledge of physiological and pathological processes, we must regard the cell as the ultimate biological unit - a unit of structure and a unit of function; this was first put forward by Schleiden in 1838, and by Schwann in 1839, but we owe to Virchow the full recognition of the fundamental importance of the living cell in all the processes of life, whether in health or disease.
In 1857 Pasteur decisively proved that fermentation was a physiological process, for he showed that the yeast which produced fermentation was no dead mass, as assumed by Liebig, but consisted of living organisms capable of growth and multiplication.
Thus, associ- 1~e] ions of Agropyrum (Triticum) junceum, of Carex arenaria, of ~ ~nmophila (Psamma) arenaria, and of other plants occur on sa rid dunes: the associations are related by the general identity ph the habitat conditions, namely, the physiological dryness f d the loose soil; but they are separated by differences in f~1
He showed that all the organs of plants are built up of cells, that the plant embryo originates from a single cell, and that the physiological activities of the plant are dependent upon the individual activities of these vital units.
AdaptationThe morphological and physiological differentiation of the plant-body has, so far, been attributed to (I) the nature of the organism, that is to its inherent tendency towards higher organization, and (2) to the indefinite results of the external conditions acting as a stimulus which excites the organism to variation, but does not direct the course of variation.
Everything you saw, that your eyeballs tracked to, how long you looked at it—and not just everything you ever looked at, but your physiological response.
Evolution, or development, is, in fact, at present employed in biology as a general name for the history of the steps by which any living being has acquired the morphological and the physiological characters which distinguish it.
- p elagic floating Hydrozoa with great differentiation of parts, each performing a special function; generally regarded as colonies showing differentiation of individuals in correspondence with a physiological division of labour.
Moreover, we have good reasons for inferring that different constellations of external causes may determine whether the internal physiological disturbances induced by a given agent shall lead to pathological and dangerous variations, or to changes which may be harmless or even advantageous to the plant concerned.
Related to the physiological drought, such plants possess some xerophytic characters; and, related to the physical wetness, the plants possess the aeration channels.
It is true that in the unicellular plants all the vital activities are performed by a single cell, but in the multicellular plants there is a more or less highly developed differentiation of physiological activity giving rise to different tissues or groups of cells, each with a special function.
He also admitted among his characteristics a physiological consideration (apparently derived from Oken 1) dividing the class A y es into two sections Altrices and Praecoces, according as the young were fed by their parents or, from the first, fed themselves.
The earliest scientific result of the study of plants was the recognition of the fact that the various parts of the body are associated with the performance of different kinds of physiological work; that they are, in fact, organs discharging special functions.
Of the precise anatomical, not to say the physiological, knowledge which appears to be displayed by the insect in stinging only the nerve-centres of its prey.
The discovery of a single fossil creature in a geological stratum of a wrong period, the detection of a single anatomical or physiological fact irreconcilable with origin by descent with modification, would have been destructive of the theory and would have made the reputation of the observer.
It is sometimes maintained, for example, by Schimper, that their xerophytic characters are related to the physiological dryness of the habitat: this, however, is denied by others who maintain (Clements, 1905: 127) that the xerophytism is due to the persistence of ancestral structures.