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Modern medicine is often said to have originated with nineteenth century germ theory, which attributed diseases to bacterial contagions. The success of this theory is often associated with an underlying principle referred to as the “doctrine of specific etiology”. This doctrine refers to specificity at the level of disease causation or etiology. While the importance of this doctrine is frequently emphasized in the philosophical, historical, and medical literature, these sources lack a clear account of the types of specificity that it involves and why exactly they matter. This paper argues that nineteenth century germ theory involves two types of specificity at the level of etiology. One type receives significant attention in the literature, but its influence on modern medicine has been misunderstood. A second type is present in this model, but it has been completely overlooked in the extant literature. My analysis clarifies how these types of specificity led to a novel conception of etiology that continues to figure in medicine today.  相似文献   

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The Welsh pantothere Kuehneotherium praecursoris   总被引:1,自引:0,他引:1  
A new genus and species of pantothere ( Kuehneotherium praecursoris ) from the Welsh Rhaetic is defined, named and briefly described. Its molars are tritubercular, with a lingual cingulum in the uppers and a tiny talonid with a large hypoconulid in the lowers. The molars and premolars do not appear to intergrade. There were between nine and eleven lower posteanines; at least five of these were premolars. The number of upper postcanines is unknown; it is unlikely to have differed by more than one from the number of lowers. The dentary terminated in a, well-developed condyle, there was no angle, and there is evidence of a full complement of accessory jaw bones including a coronoid. A new family Kuehneotheriidae is established for Kuehneotherium and related forms. The pantotheres are divided among three suborders: the new suborder Amphitheria, which includes the families Kuehneotheriidae, Amphitheriidae, Peramuridae and Paurodontidae; the Dryolestoidea and the Symmetrodonta.  相似文献   

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The third party     
Abstract. Spatial and temporal variation in interactions among plants, other species and the abiotic environment create context‐dependency in vegetation pattern. We argue that we can enhance understanding of context‐dependency by being more explicit about the kinds of direct interactions that occur among more than two living and non‐living entities (i.e., third through nth parties) and formalizing how their combinations create context‐dependency using simple conceptual models. This general approach can be translated into field studies of context‐dependency in communities by combining: progressive sampling of local variation in vegetation pattern that encompasses variation in combinations of direct interactions; spatial and temporal measures of these direct interactions; locally parameterized versions of the conceptual models; and appropriately scaled experiments.  相似文献   

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Evolution and devolution of knowledge: a tale of two biologies   总被引:2,自引:0,他引:2  
Anthropological enquiry suggests that all societies classify animals and plants in similar ways. Paradoxically, in the same cultures that have seen large advances in biological science, practical knowledge of nature has dramatically diminished. Here we describe historical, cross-cultural, and developmental research on the ways in which people ordinarily conceptualize organic nature (folk biology), concentrating on cognitive consequences associated with knowledge devolution. We show that the results of psychological studies of categorization and reasoning from 'standard populations' fail to generalize to humanity at large. The populations most commonly used in studies by psychologists (Euro-American college and university students) have impoverished experience of nature, and this generates misleading results about knowledge acquisition and the ontogenetic relationship between folk biology and folk psychology. We also show that groups living in the same habitat can manifest strikingly distinct behaviours, cognitions, and social relations relative to it. This has novel implications for environmental decision making and management, including commons problems.  相似文献   

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Some evidence of the existence of an ancient pharmacological theory—the Doctrine of Signatures—has been found in the folk medicine of Israel. The research reported 14 plants with folk medicinal uses based on the Doctrine of Signatures categories including: similarity of the plant or plant organ to the damaged human organ (Alhagi maurorum, camel thorn;Astragalus macrocarpus, milk-vetch; andCynoglossum creticum, blue hound’s tongue), similarity to animal shape or behavior (Heliotropium europaeum, European turnsole;Asteriscus spinosus, starwort; andBriza maxima, large quaking grass), similarity of plant color to the color of the disease’s symptoms or the medical phenomena (Rhamnus alaternus, Italian buckthorn;Citrullus colocynthis, bitter gourd; andEcballium elaterium, squirting cucumber), and similarity of plant habitat or characteristic to human features (Parietaria judaica, wall pellitory; andRuta chalepensis, African rue).  相似文献   

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Global demand to increase food production and simultaneously reduce synthetic nitrogen fertilizer inputs in agriculture are underpinning the need to intensify the use of legume crops. The symbiotic relationship that legume plants establish with nitrogen‐fixing rhizobia bacteria is central to their advantage. This plant–microbe interaction results in newly developed root organs, called nodules, where the rhizobia convert atmospheric nitrogen gas into forms of nitrogen the plant can use. However, the process of developing and maintaining nodules is resource intensive; hence, the plant tightly controls the number of nodules forming. A variety of molecular mechanisms are used to regulate nodule numbers under both favourable and stressful growing conditions, enabling the plant to conserve resources and optimize development in response to a range of circumstances. Using genetic and genomic approaches, many components acting in the regulation of nodulation have now been identified. Discovering and functionally characterizing these components can provide genetic targets and polymorphic markers that aid in the selection of superior legume cultivars and rhizobia strains that benefit agricultural sustainability and food security. This review addresses recent findings in nodulation control, presents detailed models of the molecular mechanisms driving these processes, and identifies gaps in these processes that are not yet fully explained.  相似文献   

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