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Presents a study on free and sulphate sulphur contents and Potential of Hydrogen (pH) values in soil profiles from barren flats and mangrove swamps of Keneba in the lower Gambia river basin. Concentrations of soluble sulphate and free sulphur content in layers of soils under vegetation and barren flats; Distribution in depth and range in pH of fresh and air dried mangrove soils; Variations in the levels and pH of water table of a barren flat during the dry season.

Describes the climate of the mangrove swamps and the physical composition of their soils in Gambia. Historical development of swamps; Distribution of chemicals in swamp soils; Levels of moisture content in swamp soils.

This article focuses on the culture of the Africans of the New World. Acknowledge of the provenience of the Afro-Americans in the New World is basic to the study of New World Afro-American cultures, since to comprehend the cultural equipment with which these people entered upon their lives in the western hemisphere is essential in any successful attempt to utilize the materials gained from investigations of their present day life for an analysis of the processes of cultural change and of the results of culture-contact. In the U.S. it has long been held useless to attempt to do more than refer African origins to such vague geographical regions as the Guinea Coast, the Congo, the Gambia, and the interior, since it is felt that documents contemporary to the period of the slave-trade have recorded place and tribal names so poorly that accurate identification of the peoples brought to the western world is impossible. Thus it is to be seen from contemporary documentary evidence that the region from which the slaves brought to the New World were derived has limits that are less vast than stereotyped belief would have them.

This paper considers the participation of macrophages, thymus-dependent lymphocytes (T-cells), and thymus-independent lymphocytes (B-cells) in man's immune response to malaria. Although phagocytosis by macrophages is an important feature of malaria the full extent of cooperation between these cells and T- and B-cells is not known. Evidence that T-cells play an important defensive role is at present unconvincing. B-cells on the other hand function importantly in the synthesis of immunoglobulins and specific antibodies and factors possibly influencing their activity are considered. Different epidemiological patterns of malaria antibodies in sera are described and the need for the routine inclusion of reliable antibody detection tests as part of malaria survey techniques, particularly where antimalarial drug usage is frequent, is emphasized.

Ninety-nine young Gambian children were studied for 61 weeks. About half of them had trachoma at the outset, and 80% of the remainder acquired the disease while under observation. IgG trachoma antibody in the serum and IgG and IgA antibodies in the conjunctival secretions (CS) were titrated by an indirect immunofluorescence method. In serum samples obtained in capillary tubes the mean titre was slightly higher than in samples collected on filter paper. Serum antibody at titres >/= 1/10 was invariably associated with a clinical diagnosis of trachoma; it increased both in frequency and titre as the disease progressed, and was present in about half of those with Tr II. In CS, IgG antibody was present less often and at lower titres than in serum, and IgA antibody was detected even less frequently. There was some evidence of correlation between the titres of IgG and IgA antibodies in CS, but none for a relationship between the titres of the antibodies in serum and those in CS. Antibodies were almost never present in the absence of conjunctival follicles, but their titres were unrelated to the degree of follicular hyperplasia; there was no obvious relationship between the serological findings and corneal lesions. In children diagnosed clinically as trachoma, serum antibody was present in almost all those with conjunctival inclusions, and in a proportion of inclusion-negative subjects; the mean titre was much higher in the inclusion-positive group.These findings do not settle whether CS antibodies are made locally, or are derived partly or wholly from the blood. They suggest that the indirect immunofluorescence test may be a useful diagnostic aid in trachoma, particularly in view of the rarity of false positive reactions; but there is at present little to choose between it and complement-fixation tests in terms of sensitivity.

Light-traps have been used successfully as mechanical sampling tools for insects of agricultural importance but medical entomologists have had only limited success because of the assumption that light-traps would attract vectors, even when sited in open fields well away from hosts. The investigations reported in this paper suggest that vectors are attracted primarily by their hosts and that only when light-traps are placed in the immediate vicinity of hosts, or in the narrow flight paths followed by host-seeking females, are appreciable numbers caught.When the CDC miniature light-trap was placed at various distances from hosts, the number of anopheline and culicine species captured decreased as the distance from the host increased. There were statistically significant differences between the means of catches in light-traps suspended on or in human dwellings, placed inside village compounds, and placed near the breeding site about 1.6 km from the nearest house. The maximum catch of Anopheles gambiae s.l. and culicines exceeded 3000 and 7000 per trap per night, respectively, and the average was in excess of 1200 A. gambiae s.l.The investigations showed that 6 anopheline species could be caught in appreciable numbers in human dwellings and thus demonstrated that light-traps could be used for sampling both endophilic and exophilic anophelines. It also appears that the effective range of the CDC miniature light-trap is about 5 m.