Six ruminally fistulated Holstein cows were utilized in a randomized block design to examine effects of yeast culture supplement on ruminal metabolism and apparent digestibility. Cows were fed a diet of 40% corn silage and 60% concentrate (DM basis). Treatments were control (supplement without yeast cells) and yeast culture supplement. Treatment periods were 6 wk. Ruminal pH, ammonia, molar proportions of acetate and isovalerate, and acetate: propionate ratio were lower and molar proportions of propionate and valerate higher in cows receiving yeast. The concentration of anaerobic bacteria tended to be higher and cellulolytic bacteria concentrations were greater in cows fed yeast than in cows receiving control diet. Supplemental yeast did not affect molar proportions of isobutyrate or butyrate, total VFA, or viable yeast concentrations in ruminal fluid. Ruminal liquid dilution rate and total tract apparent digestibilities were not different between treatments. Rate of disappearance of cellulose in vitro was lower in cows receiving yeast. Less variation in ammonia concentrations and microbial numbers suggest that ruminal fermentation was more stable in cows receiving yeast culture supplement.

Twelve lactating Holstein cows were blocked according to age and milk production into groups of three cows and assigned to three 4 x 4 Latin squares in a split-plot design with subtreatments. Treatments on each square were four diets formulated to provide -10, 0, +10, or +20 meq/Na + K) -Cl/100 g diet DM. The four balances were achieved on squares 1, 2, and 3 by manipulating Na, K, and Cl, respectively. Actual milk yield was 8.6% higher on +20 than -10 averaged across the three squares. Blood pH and bicarbonate increased linearly with dietary cation-anion balance. Rumen pH increased linearly with dietary cation-anion balance, but fermentation patterns were largely unaffected. Urine pH increased linearly and quadratically with increasing dietary cation-anion balance. Square times balance response differences proved nonsignificant for all parameters except blood bicarbonate and rumen isovalerate, indicating responses could be attributed to the dietary cation-anion balance itself rather than to the effects of a single ion. Regulation of dietary cation-anion balance may become a useful tool for improving the performance of lactating dairy cattle.

Following a general consideration of the chemical nature of compounds which provide sensations of taste or of odour, the flavour components of beer are discussed in some detail. Methods suitable for determining individual flavour compounds are indicated in relation to organoleptic assessment by a selective panel of testers. The concept of “flavour index” (flavour threshold of a component divided by the concentration of that component in beer) is introduced: substances with a low flavour index require close control in the production of beer.

SOLEREMA NEONATORUM is a rare but interesting condition peculiar to infants and is characterised by the appearance of hard well-defined thickenings of the subcutaneous tissue. It is with the material composing these swellings that this investigation is concerned. Frozen sections of the tissue show large numbers of sheaves of crystals which, seen through crossed Nicol prisms, are doubly refracting. It was the observation of the presence of these crystals which led to this work being undertaken, for their doubly-refracting nature suggested that they were probably cholesterol or its esters. Subsequent work proved that this view was probably incorrect, and the work finally took the form of an enquiry into the nature of the subcutaneous fat in normal children and in those suffering from sclerema. Observations of the behaviour of these crystals in the frozen sections of sclerema cases towards various solvents under the polarising microscope were made. By direct observation in this way, they appeared to be insoluble in ether, acetone, light petroleum, pyridine and alcohol; likewise in acid alcohol, alcoholic sodium hydroxide, water, hydrochloric acid and sodium hydroxide. It is to be noted, however, that the temperature of a volatile solvent rapidly evaporating on a slide is probably well below 00. On slightly warming, the crystals were soluble in ether, acetone, light petroleum and pyridine, but insoluble in water, aqueous hydrochloric acid and sodium hydroxide; in the other reagents they were slightly soluble. Between 400 and 500 the crystals melted, to reappear in situ on cooling and in the original form. There was no liquid crystal formation. Similar crystals with like behaviour were observed in ether extracts of the tissue. They appeared therefore to be ether-soluble and of fatty nature. Frozen sections and ether extraction of normal subcutaneous tissue revealed that there were present similar doubly-refracting crystals with like solubilities but a lower melting point. Experiments with pure tripalmitin showed that, on slow crystallisation from