1. A simple method is described for the determination of carotene and vitamin A in milk. Figures for the carotene content of milk were higher and those for vitamin A were lower than similar figures reported by Western workers.

2. Figures for vitamin C in milk are similar to corresponding figures of English and American workers. Previous low values for vitamin C, reported by Indian workers, are due to destruction of the vitamin by light.

3. The vitamin C concentration of milk is not subject to great individual variation, probably because cows cannot excrete in milk any vitamin C taken in with the food and because vitamin C of milk is produced by synthesis within the mammary glands from some simple blood constituents.

4. To test the ability of bovines to synthesize vitamin C, young calves were kept for long periods on a strictly vitamin C-free diet. The concentration of vitamin in the blood and other tissues of these animals remained, however, at a normal level. Calves appear therefore to be able to synthesize sufficient vitamin C for their normal growth and activity.

5. Unsuccessful attempts were made to produce vitamin C in vitro by growing bacteria isolated from various parts of the alimentary canal on media prepared from ingesta taken from the regions from which they were isolated.

The total solids of samples of ass's milk ranged from 7·80 to 9·10, the solids-not-fat from 7·14 to 8·50, and the fat from 0·54 to 0·71%.

The nitrogen distribution in ass's milk is: casein 39·5, albumin 35·0, globulin 2·7 and non-protein nitrogen 22·8% of the total nitrogen. Ass's milk contains: casein 0·70, albumin 0·62 and globulin 0·07%. The total protein content is 1·39%. Ass's milk is therefore characterized by a low casein, a low globulin and a high albumin content.

The non-protein nitrogen consists of amino nitrogen 8·1, urea nitrogen 24·3 and uric acid 0·7 mg./100 ml. of milk. The urea content is twice that present in cow's milk.

The mean chloride and lactose contents of the milk samples are 0·037 and 6·1% respectively.

The average calcium and phosphorus content of ass's milk are 0·081 and 0·059% respectively. Half the calcium is ionic, and half is in colloidal form.

The phosphorus distribution is: total acid soluble 84·0, acid soluble organic 38·5, easily hydrolysable ester 27·4, inorganic 46·0, and colloidal inorganic 23·0 % of the total phosphorus. The ratio of CaO: P2O5 is 1:1. 46 % of the total phosphorus is in ester form; this is high when compared with only 12 % in cow's milk; most of the phosphoric ester forms soluble barium salts, which is a distinguishing feature of ass's milk.

The total sulphur content is 15·8 mg./100 ml.

The fat has a penetrating odour and is coloured orange-yellow. It has an iodine value of about 86, which is much higher than that for human milk fat. The Reichert (9·5) and Kirschner values (5·7) are low.

In general, the composition of ass's milk resembles that of human rather than of cow's milk.

1. The direct volumetric copper reduction method of estimation of lactose in unclarified milk gives results which are in good agreement with those on the same milk clarified and decalcified.

2. For the polarimetric' or iodometric methods of estimation of lactose the milk is best clarified with either zinc hydroxide or cadmium hydroxide. Clarification with acid mercuric nitrate or phosphotungstic acid for the polarimetric method and with dialysed iron or phosphotungstic acid for the iodometric method gives high results owing to failure to remove interfering substances.

3. Dialysed iron, phosphotungstic acid, cadmium hydroxide or zinc hydroxide are all suitable for deproteinizing the milk for the chloramine-T method of estimation of lactose.

4. The values for lactose content of milk as estimated by the above methods show good agreement and therefore may be accepted as the true milk sugar content.

In the course of attempts on a field scale to eradicate or control Str. agalactiae infections, comparisons of the efficiency of several bacteriological methods have been made. It has been found that by using a method of enrichment, many cases of infection with small numbers of Str. agalactiae can be demonstrated in animals which give negative results by other methods. The frequency of examination has been shown to have an important influence upon the number of positive cases discovered.

Light infections have been, proved to persist for long periods. Light infections with Str. dysgalactiae and Str. uberis have also been found in many cases. Str. agalactiae has been shown to be present in no less than 21 % of animals in their first lactation and 4·5 % of heifers were found to harbour this organism whilst in isolation before joining the herd. The bearing of these findings on the theory of contagion in Str. agalactiae infections has been discussed.

1.Details are given of the extraction method for the estimation of the volatile acids in cheese, as used in the study of some white and blue-veined varieties.

2. On the basis of the distribution of valatile acids, hydrogen-ion concentration and nitrogen breakdown, distinctions could be drawn not only between the white and blue-veined varieties as a whole, but also between the Roquefort and Stilton groups of the latter varieties.

3. A high total quantity and a characteristic distribution of the volatile acids appeared to be related to the heavy pricking of cheese of the Roquefort group.

1. Six cheese of Cheddar type were made under conditions as similar as possible, except that the consistency of the curd at pitching, and in two cases the rate of scald, were varied.

2. Chemical and rheological analyses, as well as measurements of moisture content and vapour pressure, were made on the cheese and also judgements of firmness under various conditions were given by cheese-makers, bakers and non-experts.

3. A table is given in which the orders of placing of the cheese are compared as between the objective tests and the subjective judgements. The cheese-makers and the non-expert testers gave, in general, characteristically different orders, the orders given by the bakers tending to fall between the two.

4. It appears that the consistency of the curd at the pitching point (W/h as determined by the Scott Blair-Coppen method) and probably the rate of scald, are prime factors in determining the firmness of the cheese.

5. The whole experiment is preliminary in character and it is intended to repeat it in an extended form in the near future.

1. Hydroquinone is an effective antioxidant for the butter-fat of spray-dried whole-milk powder, but in a concentration equivalent to 0·5% of the weight of fat (0·12% on the weight of powder) it produces an objectionable ‘metallic’ flavour in the powder and reconstituted milk.

2. Oat flour is much less efficient than hydroquinone as an antioxidant but 0·25% added to the milk, preferably before condensing, increases the resistance of the resultant powder to the development of tallowiness by the equivalent of about 4 months at normal temperatures. Raising the concentration of oat flour to 0·5% approximately doubles this increase but at the same time imparts a noticeable oat flavour to the powder.

Experiments were carried out to study the effects on the quality and nutritive value of bread of the addition to white flour of roller-dried skim milk and roller-dried whey. Both samples were typical commercial products.

Additions of 2% of the dried milk could be made without any marked effect on loaf quality or on flavour. The addition of 4% or more definitely lowered the quality of the bread, the volume being smaller and the crumb more rubbery. As the content of milk was increased above 2% the flavour of the bread became increasingly distinctive and departed from the normal neutral flavour of water bread.

Up to 5% of dried whey could be added to the flour without any marked deterioration in the crumb of the bread, although with one flour this quantity decreased the volume by 16%. At this level, however, the whey imparted a distinct cheesy flavour to the bread.

Attention is drawn to the fact that the effects produced by the addition of dried milk or whey to bread can only be considered in relation to the particular sample used, since other workers have found that modifications in the method of manufacture considerably alter the value of the product as far as its use in bread is concerned. For this reason improved types of dried milk or whey might well lead to their greater use by the baking industry.