1. Crops sensitive to manganese deficiency are generally healthy on soils with more than 0·3 mg. exchangeable Mn%, but they may also be healthy on soils with less than this amount.

2. Other fractions of the soil manganese, including those which are either readily reducible or soluble in sodium hexametaphosphate, are no more successful than the exchangeable manganese in characterizing deficient soils.

1. A fraction of soil manganese soluble in buffered pyrophosphate solutions has been identified as three-valent manganese, present in the extract as a soluble complex salt of mangani-pyrophosphoric acid H[MnP3O7].

2. Evidence is given to show that a very significant part of soil manganese may be present as three-valent manganese, and that the product of oxidation of divalent manganese in soils is three-valent manganese. In any soil where the production of divalent manganese by reducing processes is going on at any appreciable rate, the oxidation of divalent manganese will supply three-valent manganese, which may therefore be expected to form a relatively large part of the manganese of certain soils.

A continuous cattle census scheme was started in the Central Province of Nyasaland in 1943, and data thus accumulated on the calving rate of native cattle form the basis of this paper.

The system of animal management prevailing in the area is described, and meteorological data collected at Lilongwe over 3 years are also given.

There was a significant positive correlation between the buffer capacity and motility of sperm and a highly significant negative correlation between the buffer capacity and the pH. There was no correlation between the buffer capacity and the volume of the ejaculate or the number of sperm per c.mm. Specimens which maintained a good motility on storage had a better buffer capacity than those which did not.

The specific gravity of 125 semen specimens was 1·0337. There was a highly significant positive correlation between the specific gravity and the number of sperm per c.mm. and the percentage motility and a highly significant negative correlation between the specific gravity and the pH. There was no relationship between the specific gravity of semen and the volume of the ejaculate, or the pH change. In general, the higher the specific gravity of the seminal fluid, the better was motility maintained on storage. The higher the specific gravity, the lower was the pH and the better the buffer capacity of seminal fluid.

The mean sugar content of bull semen was 470±11·7 mg. %. There was no relationship between the sugar content and the volume of the ejaculate, the number of sperm per c.mm., the initial motility and the maintenance of high motility during storage.

The mean percentage reduction in sugar after 24 hr. for undiluted semen stored at 10° C. was 23·85 ·1±76%. There was a significant positive correlation between the sugar reduction and initial motility, and a highly significant positive correlation between sugar reduction and the concentration of sperm. The negative correlation between reduction in sugar and the period for which good motility was retained on storage was not significant.

1. An experiment was performed to obtain information on the fluctuations in excretion of calcium, carbonate, phosphorus and chloride within the day.

2. It was found that there was a lower excretion of calcium and carbonate in the 12 midnight–8 a.m. subperiod than in the 8 a.m.–4 p.m. and 4 p.m.–12 midnight subperiods. Phosphorus showed a much smaller variation, whilst chloride gave inconsistent results.

3. When eggs were laid there was a distinct increase in phosphorus and chloride excretion and a fall in calcium and carbonate excretion. These changes, although related in time to each other, were not clearly related to the time of oviposition. Thin-shelled eggs did not give the same results, much smaller changes being observed.

4. When changes were made in the amount of calcium carbonate added to the basal ration the effect on the composition of the excreta was noted within 4 hr., the full effect showing itself within 16 hr.

5. The significance of these results in relation to egg-shell formation is discussed.

1. One laying and one non-laying bird were fed a normal calcium ration, and one laying and one non-laying bird were fed a low calcium ration. Four hours after feeding the birds were killed, and the contents of the various portions of the alimentary tract were analysed and compared with the composition of the original food.

2. The pH of the crop contents is influenced by the pH of the food. The lowest pH value is given by the gizzard contents, but after that there is a gradual rise, until, by the time the 4th segment of the small intestine is reached, the pH. is almost constant at about 6·8 for all birds.

1. The daily retention of calcium, carbonate, phosphorus and chloride was studied using four birds and changing the calcium carbonate content of the ration every 5 days for 15 days.

2. It was shown that high calcium diets result in a much lower retention of calcium and thin-shelled eggs are produced.

3. Retention of calcium was higher in the laying than in the non-laying bird when calcium carbonate was fed.

4. High calcium diets depressed the retention of phosphorus, and in one case the retention was negative, even when no eggs were laid. Laying birds gave negative values for retention because of the heavy phosphorus excretion associated with egg laying.

5. High calcium diets also depressed the retention of chloride, and on occasion led to negative retention values.

Studies on the feeding of cyclized vitamin A, vitamin-A alcohol, and vitamin-A ester (as cod-liver oil) to chicks receiving a diet of c. 13% protein content, show that chicks do not assimilate cyclized vitamin A and only begin to assimilate vitamin-A alcohol and vitamin-A ester between the 35th and 42nd day, when the results of analytical methods employed to evaluate carcass and liver stores of these substances are used as criteria, or when growth is used as criterion.

Studies on the feeding of green food and yellow maize, as sources of provitamin A, and vitamin-A alcohol, to chicks receiving a diet of c. 17% protein content, show that chicks do not utilize these substances until between the 35th and 42nd day, when the results of analytical methods are employed as criteria of assessment of vitamin A storage in carcass and liver, or when growth is used as criterion.

1. The changes which have occurred in the nutrition of young dairy stock are discussed. It is emphasized that any food shortage of a farm affects young cattle before the rations of the cows are reduced.

2. An estimate of minimum protein level is developed using Mitchell's (1926) method.

3. An experiment designed to show the optimal level of protein in the ration for growing stock showed a difference between this minimum estimate and the optimal. Some considerable economy in protein can, however, be effected in Wood & Woodman's (1936) standard is the one normally used to calculate rations.

4. The growth of young cattle on protein supplemented wartime dietaries of straw is shown to be below that of heifers fed the rations more normal in peace time.

5. Stunted cattle undergrown by 7–8 months when 18 months to 2 years old have been found. This has been attributed to the effects of wartime rations.