The extent of heterosis for number of heads per plant, seeds per head, weight per seed, and yield per plant was determined in six crosses between varieties of barley. The yield in relation to the parent varieties was determined in replicated yield trials of the same crosses in F2, F3, and F4. The yield of the parent varieties was compared also with the average yield of the F2, F3, and F4 generations for each of the six crosses. As an average of all crosses the F1 exceeded the average of the parents by 8.3% in number of heads per plant, 11.1% in number of seeds per head, 4.9% in weight per seed, and 27.3% in yield per plant. The average yield of six crosses in F2 and F3 in replicated trials, as an average of two years, exceeded the average of the parents by 24% and 13%, respectively. In F4 the average increase in a single year test was 5% over the average of the parents. It is suggested that the average yield performance of different crosses may be determined by means of replicated yield trials in the F2 or F3 generations. Such yield trials may be used for discarding certain crosses since the proportion of high-yielding genotypes in the low-yielding crosses will be less than in crosses with a higher average yield.

By means of nitrogen metabolism experiments, the biological values of 94 for white fishmeal, 81 for crayfishmeal, 71 for fishmeal, 67 for meatmeal, 67 for meat and bonemeal and 63 for whale and fishmeal were determined. From these figures and the digestibility coefficients it was shown that white fishmeal is superior in its utilizable protein content, and that whale and fishmeal is the poorest in this respect.

The distribution of carbon within morphological units (columns) from the B horizons of Solnetz-like soils from California and Nevada was determined. Quantities of carbon in the outermost layers on the column faces were, on the average, 123% of those in the central portions of the units, whereas the amounts in the light-colored caps were 55% of the amounts in the core or central portion. The carbon content decreased gradually from the face to the core of each unit and increased from the top of the column downward, at least for one or two mm layer. Quantities of carbon were low in all of the four columns or units studied.

Field percolation rates were determined on undisturbed soil profiles of two poorly-drained and two well-drained Wisconsin soils by means of a buffer compartment method. In addition, laboratory percolation rates, volume weights, total porosities, and maximum water-holding capacities were determined on soil cores taken from the different horizons and substrata of each of the four soils. The buffer compartment method was found to give good measurement of the field percolation rate of the soil and is believed to possess several advantages over the steel cylinder method which is commonly used in infiltration determinations. The lateral movement of water is diminished by means of buffer compartments, the soil structure is undisturbed, and the apparatus is simple, inexpensive, and very easily installed. The poorly drained Spencer silt loam and Superior clay loam had field percolation rates of 0.04 inch per hour or less. Percolation through the laboratory cores showed the B2 horizons and substrata to be practically impermeable to water movement. The impervious subsoils had relatively high volume weights, low total porosities, and low water-holding capacities. The well-drained Marathon silt loam had a field percolation rate of 0.3 inch per hour. while that of the Miami silt loam was 0.5 inch per hour. The laboratory percolation rates of the subsoils and substrata were over 0.4 inch per hour. In general, the subsoils of these well-drained soils had lower volume weights. higher total porosities, and higher water-holding capacities than did the poorly drained soils. The results of this study correlate well with the characteristics of the soil profiles and explain to a large extent, the differences in cropping and drainage conditions found on these soils.

A comparison is made of five methods of determining the fine ness of the fibres of each of five cottons. The methods used are weight per inch; area of cross sections; and widths of fibres col lapsed, flooded with sodium hydroxide, and mercerized without tension. Identical fibres were used where methods permitted. It is concluded that small differences may not be determined with certainty but that wide differences in fineness may be de tected by any of these methods. It is suggested that the choice of method be made after deciding whether the area the fibre oc cupies or the quantity of material in the fibre is the information desired.

1. Carotene values were determined by analysing veldgrass samples, collected monthly in the areas, Onderstepoort (Pretoria district), Ermelo (Transvaal Highlands) and Vryburg (Bechuanaland). 2. From the values for Carotene found, the daily intake was calculated and one can safely conclude that no deficiency of Carotene existed for the season August, 1939, to August, 1940, for all the areas in question. During 1938, due to low rainfall in the Vryburg area, a low intake of Carotene was registered, which was, however, still above the minimum requirement of 9 mgms. daily. Low intakes for a few months in winter (during dry periods) were found, but these instances were the exception rather than the rule.

The structural constituents, natural cellulose, hemicelluloses and lignin, in graminaceous food materials, faeces, and the crude fibre isolated from these have been determined. The results showed that: (1) crude fibre is almost wholly composed of natural cellulose but that the method for its isolation underestimates the natural cellulose content of the feed and of the faeces; (2) natural cellulose is the most digestible portion and lignin the least digestible portion of the cell-wall structure. From this finding it is inferred that a closer association exists between the lignin and the hemicelluloses than between the former and the natural cellulose of the cell-wall complex; (3) with regard to roughages the standard feeding stuffs analysis does not divide the carbohydrate complex into substances of relatively low and substances of relatively high digestibility.

(1) Details of the technique employed for the preparation of gradocol membranes are given together with the technique employed in the filtration of neurotropic horsesickness virus. (2) From data collected from the filtration of 6 strains of virus it is found that the limiting membrane is one with a porosity of 100 mµ. Hence the diameter of the virus particles is from 40-60 mµ with a mean of 50 mµ. (3) Details of the technique used for determinations by the inverted capillary method of centrifugation are given. (4) The method used for determining the density of the virus particles is given. By this method a density of 1.25 gm. per c.c. was calculated. (5) By the centrifugation method a mean value of 45.4 mµ for the particle diameter was calculated. (6) The particle diameter determined by both methods agree closely. (7) There was no significant difference in the size of the virus particles of 6 strains of different antigenic structure.

This investigation was undertaken for the purpose of developing, if possible, a procedure for measuring the small amounts of replaceable potassium found in many soils, e.g., in Alabama about 15% of the soils contain less than 40 pounds per acre of replaceable potassium. Displacement of the potassium is achieved by leaching the soil with ammonium acetate. The displaced potassium, after being freed of ammonia and organic matter, is taken up in 0.16 normal acetic acid and precipitated as potassium sodium cobaltinitrite. Complete precipitation is obtained by rapidly adding the solution containing the potassium to an equal volume of 20% sodium cobaltinitrite containing an additional 4% of sodium as the acetate. Mixing of the solutions is done at room temperature and precipitation is allowed to go to completion at about 3 degrees C. The amount of potassium present is finally determined by dissolving the washed precipitate in water and titrating with permanganate. The method is sensitive to a concentration of potassium as low as 0.005% (0.1 mgm per 20 cc).

A rapid colorimetric method for determining the base exchange capacity of soils based on the sorption of copper from a standard cupric acetate-acetic acid solution by a definite quantity of soil is presented. The exchange capacity is found by measuring the decrease in copper concentration produced in a measured volume of the cupric acetate-acetic acid reagent by a weighed quantity of soil. The acidity of the reagent is adjusted to 0.07 normal with respect to acetic acid and to 0.2 normal in cupric ions for best results. The soil is shaken with the reagent to insure a practically complete reaction and the resulting suspension is filtered. The quantity of copper remaining in a measured volume of the filtrate is determined colorimetrically by treating the filtrate with dilute ammonium hydroxide to produce the stable, highly colored cupra-ammonio complex ion and then comparing the intensity of the color produced with standards containing known quantities of copper. The values obtained by this quick method with 21 soils correlated reasonably well with those obtained by two different leaching methods and took only a fraction of the time required by the leaching methods. Visual comparison of the unknown solutions with the standards was made in a simple and convenient combination filter rack and color comparator.