Annual medical report / Tanganyika Territory.

  • Tanganyika. Medical Department.
Date:
[1924]
Catalogue details

Licence: Public Domain Mark

Credit: Annual medical report / Tanganyika Territory. Source: Wellcome Collection.

    237/246 (page 215)
    Endeavours were made to ascertain whether mechanical damage to the beans was responsible for the inhibition of growth. To this end, several beans of Chiroko and Njuglimawe were perforated, shelled, scooped or otherwise intentionally injured. Those in which the germinal area was damaged in the least degree, as also those in which the larger portion of both cotyledons was removed, failed to grow. The remainder were unaffected. Dissection of several beans revealed the fact that insects did not invariably attack the germinal area, being found in some cases at the end of a cotyledon away from it. Growth, however, was inhibited in every single instance where an insect was found in or to have attacked and left a bean, irrespective of its position in relation to the germinal area. This would lend colour to the theory that it is a secretion of or excretion from the insect that destroys the vitality of the bean. A hundred per cent, of the Maharagwe beans apparently sound that were examined, contained imagines of weevils or acari. It is interesting to note too that the perforation of the pericarp in this bean takes place from within, the portion of the husk perforated to form the exit is in the form of a disc as though punched. Beans were forwarded from Tabora, Tanga and Dar-es-Salaam, those from the former • being Njugumawe, the remainder Maharagwe. The results of experiments with these were in every particular identical with those given above. Feeding experiments with white rats, designed with a view to comparing the nutritive and vitaminic values of whole and weevil riddled seeds, had to be abandoned, as none of the white rats on arrival was in good enough condition. APPENDIX II. Experiments with Tabora Water. With reference to the request that the minimum amounts of Sulphate of Alumina and Lime required to precipitate the silica in the samples of Tabora water forwarded, be ascertained with the time required to achieve this end, the following results emerge from experiments conducted in the laboratory. Small amounts (too c.c’s.) of the water were used for each experiment, and it was found that slightly less than o-oi gramme of Sulphate of Alumina completely precipitated the suspended Silica in about 3 to 4 hours. Insufficient water was sent to ascertain the effects on precipitation, of varying amounts of lime, in conjunction with Sulphate of Alumina. Observations made during the experiments point to the probability of proportion¬ ately less alum being required in dealing with larger volumes of water. Further experiments were performed with a view to ascertaining the minimum amount of dried builder’s lime and alum, separately and in combination, required to precipitate the silica in the water samples forwarded from Kidete (Tabora district). The results of these experiments are as follows :— (a) 1. Using alum alone as precipitant the required result was obtained in 3 to 3^ hours with a minimum of -oi gramme of alum per 100 c.c. of water (10 parts per 100,000 or 7 grains per gallon).