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The paper focuses on three important themes in historical sociolinguistics: (1) the emergence of national language planning in the Netherlands around 1800, (2) the influence of historical prescriptivism on usage, and (3) genre as a crucial factor in explaining variation and change. The case study deals with relativisation, particularly the neuter relative pronoun in eighteenth-and nineteenth-century Dutch. Analysing both internal and external factors, we show that the definiteness of the antecedent does not explain the variation, contrary to what is assumed in the research literature. Likewise, a strong effect of language norms on usage patterns cannot be established. The crucial factor turns out to be genre.

The study deals with multilingualism in a historical perspective, focusing on code-switching between English and other languages in letters written in fifteenth-and early sixteenth-century England. The data is drawn from the Corpus of Early English Correspondence, a large electronic tool designed for historical sociolinguistic research. A related database containing background information on the writers makes it possible to apply the framework of correlational sociolinguistics. While testing the relationship of code-switching with many social variables, the study concentrates on social stratification. The analysis shows clear correlation between the writers' social rank and their code-switching behaviour both in terms of quantity and quality. Other interlinked variables such as gender and education are also significant. The study also confirms that for a full understanding of the phenomenon, microlevel analyses of idiolects and interpersonal relations are needed.

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The effects of chilling in the light (4 days at 50C and 100-200 micromoles of photons per square meter per second) on the distribution of chlorophyll (Chi) protein complexes between appressed and nonappressed thylakoid regions of pumpkin (Cucurbita pepo L.) chloroplasts were studied and compared with the changes occurring during in vitro heat treatment (5 minutes at 400C) of isolated thylakoids. Both treatments induced an increase (18 and 65%, respectively) in the relative amount of the antenna Chi a protein complexes (CP47 + CP43) of photosystem 11 (PSII) in stroma lamellae vesicles. Freeze-fracture replicas of lightchilled material revealed an increase in the particle density on the exoplasmic fracture face of unstacked membrane regions. These two treatments differed markedly, however, in respect to comigration of the light-harvesting Chi a/b protein complex (LHCII) of PSII. The LHCII/PSII ratio in stroma lamellae vesicles remained fairly constant during chilling in the light, whereas it dropped during the heat treatment. Moreover thylakoid membrane (3). However, some PSII of smaller antenna size can be found in the PSI-rich thylakoid region, too (2). This PSII (PSII,6) does not seem to be functionally connected with PSI (20, 27). The segregation effected by the lateral heterogeneity is not rigid, but allows many acclimative reorganizations in response to environmental changes (1).A mechanism known to regulate the distribution of excitation energy is the light-induced phosphorylation of LHCII and subsequent migration of phospho-LHCII from the appressed to the nonappressed thylakoid regions (8). In this way, the allocation of excitation energy between PSII and PSI can be optimized in varying light conditions. Phosphorylation of LHCII also provides protection against photoinhibition (15). However, low temperatures have been observed to inhibit the phosphorylation of LHCII in chilling-sensitive rice, though not in chilling-resistant barley (21,22). This probably makes rice PSII more susceptible to light-induced inhibition at chilling temperatures.High, nonlethal temperatures are also known to cause changes in the lateral distribution of thylakoid components (24, 26). Heating of isolated thylakoids to temperatures above 30°C causes migration of PSII and an inner portion of its LHCII from the appressed to the nonappressed thylakoid regions. Concomitantly, there is conversion of PSIIa to PSII,,.The migration of PSII was postulated to play a role in preventing overexcitation and subsequent damage of PSII under photoinhibitory conditions (24). This suggestion is supported by the fact that PSII, is less sensitive to photoinhibition than PSILa (10,18