DAY et al. [1931] in America first reported that they had obtained cataract in albino rats by feeding a diet deficient in vitamin B2. The ration used was that of Sherman and Spohn [1923] which has been widely employed in work with this vitamin. Cataracts were produced in 92 % of rats after an average period of 72 days.The work was developed by Langston et al. [1933] and by Langston and Day [1933] who observed an equally high incidence of cataract in mice and in young wild gray rats deprived of vitamin B2. By feeding diets deficient in vitamin B2 Day, Langston and Cosgrove [1934] obtained cataract in rats and chickens and Day [1934] reported cataract in rats, mice, chickens and monkeys. The importance of cataract as a symptom of vitamin B2 deficiency was stressed by these authors.Day and Langston [1934] published further evidence that in nearly all the cases examined rats receiving a diet free from vitamin B2 developed cataract. They found that the appearance of cataract was delayed where small but insufficient amounts of vitamin B2 were given; and the delayed appearance of cataract was correlated with the growth-rate data. It was concluded that cataract was probably a better criterion of vitamin B2 deficiency than was dermatitis.These observations are of great interest since they are related to the problem of the aetiology of cataract as well as to that of vitamin deficiency. It is important that it should be established beyond doubt whether or not degenerative changes in the eye-lens can be produced by the omission of a specific substance, such as a vitamin, from the diet. It is equally important from the point of view of vitamin studies to know if cataract, which can readily be observed, is in fact a consistent symptom of a vitamin deficiency. In addition a technique for producing cataract regularly in a laboratory animal by dietary control would prove most useful in further studies in the aetiology of cataract. For these reasons it was considered advisable to attempt to repeat the work of Day and his colleagues. Experiments were therefore undertaken in which diets deficient in vitamin B2, including the Sherman and Spohn [1923] diet as used by the American workers, were fed to rats and the eyes examined with an ophthalmoscope at weekly intervals. The results of these experiments form the subject of the present communication.EXPERIMENTAL. Thirty-six young black and white rats of about 70 g. weight were obtained from a commercial source and kept in single cages with wire screen bottoms. The Sherman-Spohn [1923] diet was fed. This consists of alcohol-extracted caseinogen ( 1865 )

The special character of grain whisky distilled in Scotland depends on a number of factors. The conversion of the starch from cooked maize during the mashing process by the diastatic activity of barley malt is done in such a way that, besides a spectrum of soluble sugars, oligosaccharides and dextrins, some insoluble solids are also present. A significant proportion of initially unfermentable material becomes fermentable by a process of secondary conversion during the fermentation stage in the distillery. The fully fermented worts contain, besides ethanol, the higher alcohols, N‐propanol, N‐butanol, iso‐butanol and iso‐amyl alcohol, certain esters and aldehydes, and glycerol. After distillation in a Coffey still, the whisky contains higher alcohols, esters and aldehydes derived from the fermented worts. Lactic and acetic acids are also present as a result of fermentation by microbiological flora other than yeast. Among the changes in composition that take place during the maturing process are increases in the concentrations of esters, volatile acids and aldehydes.

WHEN vitamin B1 is oxidized in an alkaline medium it is converted into thiochrome [Barger et al. 1935]. This substance has a vivid blue fluorescence which can be detected in dilutions of 1: 2,000,000. Recently Jansen [1936] published a quantitative method for the measurement of vitamin B1 which was dependent on the conversion of the vitamin into thiochrome and the subsequent measurement of fluorescence by means of a photoelectric cell. When it was attempted in this laboratory to apply the method to the measurement of vitamin B1 in foodstuffs certain difficulties arose. The following paper indicates the limitations of the method and the means which were devised in order to overcome them.Since the completion of the work reported below, two papers have appeared in which the thiochrome reaction for the measurement of vitamin B1 has been used. Karrer & Kubli [1937] have used Jansen's method with very little modification for preparations of high activity (between 500 and 220,000 i.u. per g.) which had been prepared during the production of crystalline, natural and synthetic vitamin B1. With substances of this high activity, these workers found it more convenient to compare the intensity of fluorescence by eye rather than use the somewhat delicate fluorimeter of Cohen [1935] in which a photoelectric cell is employed. Where vitamin B1 in foodstuffs is being measured, however, comparison by direct observation is not sufficiently accurate.Another Tecent paper by Goudsmit & Westenbrink [1937] reports the use of a procedure almost identical with that devised by the author for the measurement of vitamin B1 in urine. EXPERIMENTAL(1) Standardization of the reaction with International Standard adsorbate The procedure of Jansen [1936] was carried out with very slight modification. 0-1 ml. of 1 % K3Fe(CN)6 was required to oxidize each 10 mg. of acid clay. This solution was mixed with 2 ml. redistilled methyl alcohol and 1 ml. 30 % NaOH, and the accurately weighed and finely powdered International Standard added. The reagents were shaken for a few moments and made up to 5 ml. with water, and 13 ml. of isobutylalcoholwere added. The mixture was again vigorously shaken and finally centrifuged.The measurement of fluorescence was carried out on the Cohen fluorimeter. The blank reading obtained with 10 ml. of the original isobutyl alcohol was subtracted from the galvanometer deflexion given by exactly 10 ml. of isobutyl alcohol solution. Compensation for any variation in the intensity of the ( 1958 )

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