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dissolved in drinking-water to make -J per cent, solution, (b) as dolomite (magnesium calcium carbonate) sprinkled on ensilage, and (c) as licks composed of 50 per cent, agricultural salt and either Epsom salts or dolomite. Method (a) was successful in producing a small but definite increase above the normal blood magnesium, accompanied, however, by a small drop in blood calcium. The consumption of water was not affected by the presence of Epsom salts, the cows appearing, in fact, not to object to the taste. Method (b) also produced a similar rise in blood magnesium, but without the fall in blood calcium—this doubtless being due to the influence of the calcium in the dolomite. No blood analyses were made in the ease of the lick experiments. It was observed that the animals at first ignored the licks but later took the Epsom salts or dolomite lick with equal readiness, although both were presented side by side. Again the taste factor of Epsom salts was negligible. The general conclusions from this work are that the blood magnesium of dairy cows may be increased by feeding magnesium, and that simple methods of doing this are by dissolving Epsom salts in drinking-water or by sprinkling dolomite or Epsom salts on ensilage or hay. Since grass staggers is characterized by a very low blood magnesium it is possible that prevention might be achieved by supplying magnesium during the period of greatest susceptibility. As a therapeutic agent sugar-cane molasses was investigated. This material contains considerable amounts of calcium and magnesium. Experiments on sheep have shown that the calcium and magnesium are very readily absorbed into the blood stream, producing considerable increases in the concentration of these constituents in the blood. The effect was greater than that produced by inorganic salt mixtures containing the same quantities of calcium and magnesium. Molasses may therefore be shown to be valuable against both grass staggers and milk fever, and if successful would be particularly useful since it may be advised for use by the farmer himself when the case is inaccessible to a veterinarian. To determine the influence of manurial treatment with magnesium on the magnesium and calcium content of pasture, sixteen plots have been laid down in a Latin square with four replications of the following treatments : (a) Epsom salts, (6) dolomite, (c) calcium carbonate, and (d) control. Results are not yet completed. Cause of Grass Staggers. —Sheep are being used in the preliminary phases of this work since they are cheaper and more easily handled than cattle. The experiments owe their inception to the fact that whenever grass staggers occurs the onset is practically always associated with ingestion of young growing grass. Sheep are being kept on hay and drenched with substances which occur in young pasture. So far malic and citric acids have been tried. It has been found that ingestion of malic acid has no influence whatever on blood calcium or magnesium. Citric acid, however, causes a temporary rise of from 10 per cent, to 15 per cent, in both of these constituents soon after drenching with moderately large quantities. This effect is possibly due to some favourable influence in absorption. Further experiments are proceeding. DETERMINATION OF MAGNESIUM IN BLOOD. An investigation into the method for this determination, which has been conducted in collaboration with Mr. S. W. Josland, has been concluded satisfactorily. High Protein Feeding and Sterility. This work on rats is being continued in collaboration with Mr. C. S. M. Hopkirk. Rats are being fed on diets containing different levels of protein of both animal and vegetable origin, and periodic examinations of sperms and testes are being made. The report made previously that high levels of protein in the diet do not influence the fertility of females has been confirmed in a more comprehensive experiment. Growth of Wool on Angora Rabbits. Investigations of the complaints of a.ngora-rabbit breeders that wool production was small showed that the diets commonly employed were inadequate chiefly in protein, calcium, iron, and Vitamin D. Two breeders are carrying on experiments on their own rabbits in which these deficiencies are made £ood by supplying blood meal, calcium carbonate, limonite, and cod-liver oil. Vitamins. Vitamin work is being carried out by Dr. Marion M. MeOwan, who has been granted a Carnegie Scholarship for work in New Zealand. The main work involves a survey of the Vitamin D content of New Zealand fresh-water and marine fishes. The preliminary results show that whale oils, eel oil, and tarakihi-liver oils are high in Vitamin D content. In addition to this the Vitamins A and D in skim-milk have been assayed, using samples from milk employed by Mr. C. S. M. Hopkirk in a feeding experiment on young pigs. •It has been found that skim-milk contains practically no Vitamin A or D, whereas fresh milk has a fairly good supply. The observed deficiency of Vitamin A in skim-milk assisted in implicating avitaminosis A in the widely observed paralysis in young pigs fed mainly on this substance. BIOCHEMICAL WORK PERFORMED BY Mb. S. W. JOSLAND. Mr. Josland supplies the following sub-report : — Method for Determination of Magnesium in Serum. —As a result of several modifications in technique the micro method now in use gives satisfactory results. Using the modified technique the following values have been obtained on serum from several kinds of animals :—

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Mg. in Serum (nigms. per 100 c.c). Tnttlp Sheen Tint T>i«r COWS With tattle. bneep. Bat. ttg. Grass Staggers. j i Average.. .. .. .. .. 2-3 2-5 2-5 2-5 1-1 Range of variation .-. .. .. 1-7-2-8 1-9-3-1 2-0-3-0 1-9-3-8 0-7-1-7 No. of determination ...... 22 70 59 17 11