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The article informs that modern students of human migrations set out initially with two categories of human movements. These they label as modern and prehistoric. Conclusions about the latter must necessarily be good guesses, but a good guess is permissible in any science where evidence from current observations is available for making generalizations and comparisons. Of the social, human interactive forces governing prehistoric migrations, nothing certain is known. But in the consideration of modern migrations much is known and may be deduced- Students have, therefore, divided modern migrations into various categories. Thus, in the modern sense, we may find religious movements, political movements, aggressive wars, and adventuring as categories of human migrations. Modern movements may be classified broadly as social and practical. The latter type of migration is brought about by population pressure, famine, drought, and similar natural phenomena. The former type includes such movements as those brought about by a search for political refuge, those instigated by labor recruiting, and by religious migrations. But there are factors basic to all human migrations which this paper attempts to deal with as initial phases of study. The logic is based on two major assumptions: that all men wish to survive; and that all men need land for-survival.

Acute phosphorus deficiency was induced in seedlings of a number of species over a period of 5 weeks. Deficiency affected dry weight, root/shoot ratio, leaf water content, leaf water deficits and the time taken for the plants to show visible stress after watering was stopped. Populations of two of the species from soils differing in phosphorus status showed consistent and major differences in the effects of phosphorus deficiency. The ecological implications of the results are discussed. [ABSTRACT FROM AUTHOR]

The article presents information on several articles about drought resistance in ferns. One author stresses that the means of protection against strong insolation and transpiration are much the same among ferns. Another author offers details of the anatomy of four species of Cheilanthes and Pellaea andromedaefolia. One article points out that little is known regarding drought resistance in fern prothalli. An article also emphasizes that the part played by the prothalli in the ecological history of ferns has received little attention.

Tissue injuries in winter are sometimes interpreted as caused by drought damages. The possibility that the tolerance of conifers of winter and spring conditions is increased through decrease in transpiration rate has been little investigated. The transpiration rate of 3 or 6 months old unhardened, hardened, and dehardened seedlings of Pinus silvestris L. and Picea abies (L.) Karst. was assessed gravimetrically, at 20°C. The transpiration rates of seedlings of spruce and pine which had been hardened for 3 months were about ½ the raes of dehardened seedlings. Transpiration during a dehardening period increased at different rates in pine and spruce. After a dehardening period of 3-5 days the transpiration rate of spruce reached a maximum, whereas pine reached the maximum transpiration rate after a dehardening period of 10-14 days. Transpiration of seedlings of spruce and pine hardened for 3 months showed only a very slight reaction to light and darkness. This indicated that stomata of hardened seedling remained closed. The results are discussed in connection with frost and drought injuries in pine and spruce during early spring. [ABSTRACT FROM AUTHOR]

The article discusses the presowing treatments and their relation to growth, drought, frost and heat resistance. Winter wheat grains were soaked in water at room temperature. After 30 hours, when the radicle just started to emerge, the grains were blotted and left dry under room conditions until they reached their original weight. The results of the growth experiments reveal no significant differences between the shoot or roots weights of the various pretreatments. The results of the drought tolerance tests indicate as well that no induction of a higher drought tolerance could be seen under the conditions of the experiments.

This article presents a study regarding the tissue water relations of some wooden species of the Accra Plains in Ghana. It discusses that extensive evidence exists to indicate that plant distribution in West Africa is to a great extent controlled by some aspect of the moisture factor of the environment. The principal division of the natural vegetation of this area into forest and savanna is believed to reflect this control, savanna species having greater adaptation to drought that forest species.

The article presents a study on the water relations of Erica cinerea, Calluna vulgaris and Vaccinium myrtillus from open and shaded habitats. It states that in general, the shade plants were found to be more sensitive to water stress than plants from the open sites. It mentions that the differences between sun and shade plants were least noted in Vaccinium than Erica or Calluna. Shade samples of the three species, however, appear to retain their increased sensitivity to drought throughout the year.

The article presents an ecophysiological studies on Rhagodia baccata (Labill.) Moq. in arid and semi-arid regions in western Australia. The study reveals that the plants exert control over water loss and have a higher net assimilation rate as compared to other native plants of Western Australia. Moreover, the plants also have a high resistance to heat and has drought-resistant properties. These also exhibited capacity to grow on a wide range of soil types, ease of propagation, and pallability for sheep.

The article presents an experiment which examines the significance of light rainfall to the survival of plants, particularly maize, in East Africa. Maize, a type of corn, is an annual field crop across the region. It explores the water distribution of the plant's root system during dry seasons. Findings reveal that the amount of water available to the plant from each shower depends on the water holding capacity of the soil. It states that the plant's surface, which will be exposed to the rain, varies to its canopy structure.

The article presents a study on the habitat and plant species in the desert of Egypt. The vegetation were classified into five types including ephemeral, drought-deciduous, succulent and evergreen. Meanwhile, the four types of plant growth in the area includes summer, deciduous, succulent and evergreen. The vegetation has certain common features which pertains to structure, composition and dynamics. Meanwhile, one of the types of vegetational changes is slow and gradual which is due to the gradual building up of the surface deposits.

The article provides information on the British species of Silene nutans L., a perennial herb with a tough, branched, woody stock and deeply ramifying roots. It has been found that the degree of exposure to wind and drought affect the stature of the plants in Britain. It enumerates the vice-counties where the plant is well-established. Information is presented on the habitat, climatic and topographical limitations of the plant. It offers a list of various soil types on which the species occurs. It relates the effect of frost and drought on the plant.

The article presents a study that investigates the drought resistance (DR) and water relations of plants in the Near East. It discusses DR problem among plants, suggests principal ways of balancing water to escape plants from death, and evaluates the effectiveness of equilibration of water. It states that the rhythm of plant life in the country reflects the regular interchange of a winter vegetation that adapted to the wet and cool conditions of the rainy season and a drought-resistant summer vegetation.

The article offers information on the vegetation of the Venezuelan llanos. It states that the elevation of the llanos is in general no more than 250-300 ft. above sea-level. Relative to this, the most marked climatic feature is the very long drought-stricken season (from November to March) rendered still more damaging to vegetation by the dry north-east wind. Moreover, it is mentioned that the llanos between the Coastal Cordillera and the Apure River consist for the most part of bunch grass savannah. The dominant grasses are Cymbopogon rufus, and over smaller but still extensive areas, the Andropogon condensatus and Sporobolus indicus.

The article highlights a report discussing the pleistocene climatic changes and the distribution of life in East Africa. It reports that the present evergreen forest boundaries are generally not natural, noting that they have been reduced by human agency as much as they would have been appreciable drop in rainfall. It discusses the changes that have occurred in the West African forest for a period prior to 400,000 thousand years ago. It also examines the impact of the subsequent dry period in the areas including Elgon, Kilimanjaro, and the highland forms in Southern Tanganyika Territory.

The article discusses the process of wilting of plants relative to the phenomenon of drought resistance. An experiment was conducted to test plants and measured the daily rate of transpiration and absorption of water. Results showed that, in the morning, transpiration increases much faster than absorption while there is greater absorption in the evening hours. Leaves of the plants subjected at midday to the direct sunlight are on the limits of wilting. Although wilting is accompanied by an extreme reduction of the rate of transpiration, the author declares that wilting must also be considered as one of the major means of preserving the plant's water content in periods of drought. He concludes that the rate of transpiration cannot be used for judging the drought resistance of a plant.

Shoot extension, leaf growth, xylem radial growth and xylem structure in 1-year old Liriodendron tulipifera L. seedlings maintained in a growth chamber were affected more by reduction of atmospheric relative humidity from about 95 to about 45% than by simultaneous reduction of the root medium water potential(∊[SUBsol]) from - 0.4 to about - 11 bars. For plants subjected to the same minimum ∊[SUBsol] the rate of change of ∊[SUBsol] during the imposition and relief of simulated drought had no apparent effect on growth. Xylem formed near the stem base during a period of simulated drought resembled that characteristic of the terminal stage of seasonal growth under normal conditions; vessel elements, fibres and ray parenchyma cells were narrower in the radial direction, vascular rays increased in width and more vertical parenchyma was evident than under conditions of rapid growth. The differences between the structure of xylem formed at high and low plant water potentials diminished towards the apex of the stem and it is suggested that these differences may be due chiefly to an impairment of synthesis and translocation of growth factors. [ABSTRACT FROM AUTHOR]

The article focuses on the state aid given to drought sufferers in Haskell County, Kansas. Since the settlement of the county in 1885, marked deficiencies of rainfall have occurred in 1887, 1889, 1893-1897, 1899-1901, 1907-08, 1910-11, 1913, 1916-17, 1924, 1926 and 1932-36. The last drought was the worst in the history of the county. But unlike the previous droughts, there was less emigration, less dislocation of schooling and other community agencies and less interruption of social and economic life generally. This is to be accounted for by the federal assistance in the form of farm loans, relief grants, assistance by the Farm Security Administration, through Work Progress Administration and National Youth Administration projects and Agricultural Adjustment Administration benefit payments which ran as high as $450,000 per year from 1933 to 1936 and were received by ninety per cent of the farmers. During the droughts of the 1880's and 1890's Haskell County was almost depopulated by migration of distressed settlers.

This study of a drought area county in the Southern Great Plains attempts to analyze the effects of recurrent droughts on population, systems of farming, standard of living, community organization, public relief and assistance, and attitudes and opinions. A striking similarity of the effects of drought upon community life is apparent in a comparison of several drought periods. The general pattern of social changes during drought is summarized. An outstanding feature of the recent drought of 1932-36 has been the large amount of federal assistance which has served to stabilize the farming economy. Recommendations to avert the most disastrous effects of future droughts do not involve a complete shift from wheat growing hut rather a better adaptation of this type of farming to the climate of the Great Plains along with increased diversification and greater emphasis on measures designed to control soil blowing. [ABSTRACT FROM AUTHOR]

Reports on the relief program organized by the Ethiopian Nurses Association aimed to bring assistance to the regions in the country that have been affected by droughts. Bases of the program; Move done by "International Nursing Review" to assist the association to carry out the program.