DR. WATSON'S book shows clearly the wide range of scientific knowledge which is required by those who work in the tropics either as physicians or as sanitarians. It is unnecessary nowadays to insist upon the importance of the control of malaria in the development of those vast areas from which is derived so much of the food supplies and raw materials of manufacture of all civilised countries, but only those who have had practical experience of the methods used to deal with the disease can appreciate how many and how varied these must be.
LABOURERS in factories in South Malaya who cut up pineapples by hand for canning invariably show an abnormality of those parts of the body which are exposed to slight pressure and pineapple juice, notably the palmar surfaces of the fingertips and the periphery of the palms. At the beginning of the canning season, the left hand, which comes more into contact with the fruit than the knife-holding hand, becomes sore and small superficial raw areas on the fingertips are often seen. Within several days, however, these heal, and the skin ceases to be sore. The labourers state that this tolerance to the pineapple juice is due to the development of an abnormality of the skin, which in the affected area becomes bluish-white and so smooth that fingerprints may be completely lost. Deep cracks are sometimes seen in the region of the skin creases. These often stay raw and bleeding for a long time, and show no clinical signs of infection, presumably because of removal of dead tissues by enzymatic action.
IN connexion with a programme of studies of the relationships between biochemical and ethnological differentiations (some aspects of which have already been discussed1) proceeding in this Department, we wished to explore the possibility of improving existing procedures for the estimation of amino-acids separated on paper chromatograms2, before beginning an investigation of the patterns of urinary excretion of amino-acids by normal members of various ethnic groups living in Malaya.
ANTHROPOLOGISTS are again indebted to Mr. Ling Roth for presenting to them, in a convenient form, the results of wide reading and diligent compilation. It is by such well-directed enthusiasm that the labours of the student are materially lightened; for not only has the author, in this instance, marshalled a portentous array of accurately acknowledged quotations, but he has sedulously collected illustrations of objects preserved m numerous museums and private collections, in order to fully illustrate the descriptions that he quotes.
BEFORE Sir Ronald Ross's epoch-making discovery, there was no more puzzling problem in medicine than the cause of malaria; no secret in Nature more cunningly hid than the malaria secret. Malaria was known to be connected with swamps, and to be reduced by drainage and cultivation. Yet, as if merely to confuse, men found that to flood some swamps actually improved health; and elsewhere that drainage and the cultivation of the soil produced the most serious and devastating outbursts of the disease. Yet again, malaria was found not only in swamps, but also often on hills and dry sandy deserts. Some jungle-covered land was singularly free from malaria: other jungle land was intensely malarial. In fact, malaria existed on soils of every conceivable variety, of every age in geological time. It was-impossible to point to any mineral, chemical, or vegetable condition essential to its presence. It was, and had been for hundreds of years, a dark, inscrutable mystery.
The tropical forests of Borneo and Amazonia may each contain more tree species diversity in half a square kilometre than do all the temperate forests of Europe, North America, and Asia combined. Biologists have long been fascinated by this disparity, using it to investigate potential drivers of biodiversity. Latitudinal variation in many of these drivers is expected to create geographic differences in ecological and evolutionary processes, and evidence increasingly shows that tropical ecosystems have higher rates of diversification, clade origination, and clade dispersal. However, there is currently no evidence to link gradients in ecological processes within communities at a local scale directly to the geographic gradient in biodiversity. Here, we show geographic variation in the storage effect, an ecological mechanism that reduces the potential for competitive exclusion more strongly in the tropics than it does in temperate and boreal zones, decreasing the ratio of interspecific-to-intraspecific competition by 0.25% for each degree of latitude that an ecosystem is located closer to the Equator. Additionally, we find evidence that latitudinal variation in climate underpins these differences; longer growing seasons in the tropics reduce constraints on the seasonal timing of reproduction, permitting lower recruitment synchrony between species and thereby enhancing niche partitioning through the storage effect. Our results demonstrate that the strength of the storage effect, and therefore its impact on diversity within communities, varies latitudinally in association with climate. This finding highlights the importance of biotic interactions in shaping geographic diversity patterns, and emphasizes the need to understand the mechanisms underpinning ecological processes in greater detail than has previously been appreciated.