The alkaloids of Ragwort (Senecio jacobæa Linn.) are known to be hepatotoxic to farm animals and man. Survivors invariably show permanent impairment of the liver, manifested by cirrhosis and its sequelæ. Senecio infusions may be consumed in small amounts in Britain as a herbal remedy, and in South Africa the Bantu frequently incorporate them in native medicines. It has been shown that these tribes have a high incidence of cirrhosis and primary liver cancer, and there is good evidence that their deficient diet may play an important part in sensitizing the liver to toxins. In the present study, the ragwort alkaloid seneciphylline has been administered by injection to fowls maintained on both adequate and deficient diets, and further fowls received the dried plant in their food. A significant proportion of these birds subsequently developed primary liver tumours. Although there was a higher mortality rate in both treated and controls fed the deficient diet, there was no evidence of a greater tendency to develop liver tumours compared with the birds on the balanced diet.

It is also suggested that the condition known as “cavernous angioma” of the liver of cattle and sheep in Britain may be due to ingestion of ragwort in sub-lethal amounts.

Brief exposure in the young stage to carbon monoxide in concentration c. 1 per cent modifies subsequent sex expression in male plants of the dioecious Cannabis sativa (hemp), inducing the formation of intersexual or even functionally female flowers. The effect is registered in flower primordia of a particular age; older ones are already sexually committed, and younger ones apparently recover from treatment to pursue the genetically established path of ontogeny. Grafting experiments show that the stimulus is retained in the apex even when it is transferred to an untreated plant before the flower primordia have begun differentiation.

The effect of carbon monoxide in modifying sex expression is similar to that induced by auxin administration, and it is possible that the basic function of the gas at the effective concentrations is to upset auxin metabolism in treated tissues, perhaps by inhibiting enzyme systems normally responsible for regulating endogenous auxin levels.

The mineral base of the soils in Islay, Tiree, Coll and the Outer Hebrides is composed mainly of erosion products of Lewisian and Torridonian rocks, together with materials taken from solution in the sea biotically, and subsequently deposited in the form of shell-sand on the windward coasts. The soils composed for the most part of erosion products are acid, and those of marine products basic. Along transect lines at right angles to the coast there is in many places a wide range of soil conditions from calcareous sand to peat, in distances of about 1 kilometre.

The distribution of the Lumbricidæ, a group known to be affected by pH, available calcium content, and moisture content of the soil, is studied within this range in soil types. Seventeen species are involved, three of which are grouped (in numerical considerations) owing to taxonomic difficulties, and these are described in groups living in the main ecological zones of the soil habitat. Relationships are found between the abundance of those species and soil types.

The occurrence of earthworms in three different soil niches—open soil, in and under cow-pats, and under stones—is described, and niche preferences of the dominant species discussed.