H.—29.

has shown greater fluctuation in cobalt content than last year, and some recent samples have contained in the vicinity of only 10 p.p.m. While this may be sufficient to maintain stock health the amount, required is almost certain to be greater than in the case of limonite containing ten times the amount of cobalt. Supplies to Farmers : In view of the trouble experienced by many farmers in obtaining supplies of cobalt at reasonable prices, the difficulty of mixing the extremely minute amount required with salt for lick purposes, and the somewhat erratic cobalt content of limonite, it was decided to make cobalt sulphate available for sale to farmers. A red-coloured, strongly cobaltized salt giving, when mixed with agricultural salt at the rate of 1 lb. to 1 cwt., a product containing 4 oz. of cobalt sulphate per ton of lick, is sold at 2s. per 5 lb. bag. Cobalt sulphate is sold in 1 oz. bottles, with full directions for drenching, at Is. per bottle. During February and March 348 bags of cobaltized salt and 321 bottles of cobalt sulphate were distributed to district offices for sale, and much larger orders are now coming to hand. lodine Survey of New Zealand Live-stock. —The concluding paper dealing with the iodine content of South Island glands covering the Nelson, Marlborough, and Westland districts and summarizing the results for the South Island as a whole has been published by Mr. D. F. Waters in the Transactions of the Royal Society of New Zealand. A final paper covering results from the North Island is in preparation. Pica, Osteomalacia, Waihi Disease, &c.—Several occurrences of trouble with cattle or sheep, suspected of being connected with deficiency of phosphorus, or unbalanced phosphorus calcium ratio, have been investigated from the point of view of the percentage of these elements present in the pastures on which the animals were grazing. On a property at Onewhero, near Tuakau, Raglan County, very persistent bone and stick chewing had occurred among dairy cows, and over a number of years young cattle and sheep had failed to thrive. Analyses at the Veterinary Laboratory had demonstrated low levels for inorganic phosphorus in the blood. Samples of soil and pasture, collected on a personal visit, when analysed supported the contention that deficiency of phosphorus was the cause of the trouble. The soils were leached volcanic ash loams with high lime requirement, high soluble alumina probably resulting in strong phosphate fixation, and with very low contents of total and available phosphoric acid. The pastures contained approximately 1 per cent, of calcium oxide, but only about 0-4 per cent, of phosphoric acid. It was subsequently demonstrated that feeding with bone-meal, when persisted in long enough, overcome the stock trouble. In connection with an outbreak of bandiness in hoggets near Balclutha, turnips on which the animals were being fed were submitted by the Officer in Charge, Veterinary Laboratory, for analysis. The roots from Balclutha contained 0-43 per cent, calcium oxide and 0-75 per cent, of phosphoric acid on the dry weight, while other turnip roots from Ruakura for comparison contained from 0-6 per cent, to 0-7 per cent, of calcium oxide and 0-4 per cent, of phosphoric acid. Mineral Deficiencies and Fruit Tree Growth. A considerable number of citrus-tree leaves have been analysed in connection with a chlorotic condition of the leaves and general unhealthiness of the trees. Some indications of positive response to zinc spraying have been obtained by the Horticulture Division in the Tauranga area, and analyses point to a zinc content of the young leaves of from 5 mg. to 20 mg. per kilo, of dry matter being associated with such conditions, while healthy trees usually have above this level. In the Auckland district joint investigations by the Horticulture Division and the Department of Scientific and Industrial Research indicate a deficiency of manganese as a contributing factor to chlorotic conditions, and leaves of the affected trees were found to vary in zinc content from 16 mg. to 31 mg. per kilo., and in manganese content from 5 mg. to 12 mg. per kilo. Samples of leaves taken under a standard system have been obtained from manurial trials in apple orchards. The analyses when completed will be compared with results as indicated from qualitative and quantitative results on yield and vigour of the trees. Pig Feeding and Carcass-quality. A co-operative series of feeding experiments are being carried out at the Ruakura Farm to determine the effect upon bacon-quality of variation in the nature of the rations, and particular attention is being paid to hardness of fat as influenced by milk, grain, and pasture. Dr. F. B. Shorland is analysing the body-fat from selected portions in the carcass to obtain the distribution of the various fatty acids in an endeavour to correlate the composition of the fat with that of the food. Vitamin A Content of Butters. Through the kind assistance of the Director of the Dairy Division a series of butter samples are being secured from the grading-stores in the various districts with the object of determining local and seasonal variation in vitamin A and carotene content of New Zealand butters. A spectrophotometer is being secured for this and other related work, and will be used in conjunction with the Hilger spectrograph in the Dominion Laboratory. Stock-foods. Arising out of inquiries initiated by the Standards Institute, a survey was made of meat-meals, meat and bone-meals and pollards produced and sold in New Zealand. From the results obtained tentative proposals have been drawn up for standards covering these products. The proposals are at present under consideration by the interested parties. All the samples analysed were of a reasonably good standard, but some confusion appeared to exist in some cases as to the designation of particular products. Certain samples labelled meat-meal would more correctly be described as meat-and-bone meal, as they contained from 16 per cent, to 29 per cent, of ash.

58