A study was made of four methods for the determination of the amount of exchangeable H in soils. The methods were used on 12 sods of widely different texture, origin, and content of exchangeable H. The H content of a soil was assumed to be equal to the difference between the exchange capacity of the soil and its content of exchangeable bases. This difference was determined. Exchangeable H was then determined by titrating the soil to pH 7.0 with Ba(OH)2 by determining the amount of H replaced by leaching the soil with neutral Ba(C2H3O2)2, and by conductometric titration. The results may be summarized as follows: 1. The difference method, titration to ph 7.0, and the Ba(C2H3O2)2 method give similar results for exchangeable H when compared on 12 Soils. 2. The conductometric titration method is unsatisfactory for the determination of exchangeable H. 3. Acid soils do not contain an appreciable amount of exchangeable Fe and Al. 4. A tentative method, the Ba(C2H3O2)2-NH4Cl method, for the determination of exchangeable H is described.

The need of methods for the accurate determination of replaceable bases in calcareous soils is pointed out, and some of the faults of the earlier procedures, when applied to soils containing CaCO3, are discussed. The method which is proposed for the quantitative determination of replaceable bases in calcareous soils employs alcoholic salt solutions as the displacing agents. We prefer 0.1 N BaCl2 in 68% ethyl alcohol. Percolation, rather than shaking with subsequent filtration, is advocated where large numbers of determinations are to be made. The alcohol is evaporated, the residue is taken up in water and made up to volume, the excess Ba is precipitated as the chromate where Ca and Mg are to be determined or as the sulfate where Na and K are sought. Subsequently, the bases are separated by appropriate methods. Where "alkali salts" are present, these are removed by leaching with pure water before the soils are treated with the replacing solutions.

Bees were kept in an indoor hive and could reach the outside only through a glass-covered low gallery. In the middle of this was a passage 5 cm. wide, closed by 2 parallel elastic bands. A light push on the elastic was sufficient to restrain her, to mark her or to sample (with a needle) some pollen from her she collected. The species of the pollen was identified. Most bees spent the whole day on one plant species and repeated this several days. Water collectors were marked at the drinking place. They spent the whole day collecting water from one site. By bringing their tongues momentarily into contact with pollen during drinking, these bees suddenly changed their behaviour. They no longer looked for water at the drinking place but for the sweet material they had encountered. They returned to saucers of sugar syrup for days on end. These and complementary observations showed that the environment of the worker bee was extraordinarily limited. Her behaviour was primarily determined by habit.

Tobacco (Turkish) has been used with very successful results as an indicator plant to show the fertilizer response of soils under greenhouse conditions. A deficiency in available supply of a nutrient element is evidenced by significant yield reduction and physiological characteristics of tobacco grown on soils unfertilized with that particular element. No correlation between response and total amounts of nitrogen, phosphorus, or potassium was observed on any of the 24 different soil types under investigation, but a good correlation existed between phosphorus response and amounts of soil phosphorus soluble in 0.01 N sulfuric acid as determined by the coereleomolybdate method. Potassium availability was apparently reduced by liming under the conditions of these experiments. Lime had no beneficial effect except on soils at pH values below 4.8 pH. On soils below 4.2 pH abnormal plants were produced, and the injurious effects of this degree of acidity may be associated with toxicity of soluble aluminum or manganese, or both. Data given in this paper are incidental to the discussion and final conclusions should not be attempted until the investigations are concluded.

Bees were kept in an indoor hive and could reach the outside only through a glass-covered low gallery. In the middle of this was a passage 5 cm. wide, closed by 2 parallel elastic bands. A light push on the elastic was sufficient to restrain her, to mark her or to sample (with a needle) some pollen from her she collected. The species of the pollen was identified. Most bees spent the whole day on one plant species and repeated this several days. Water collectors were marked at the drinking place. They spent the whole day collecting water from one site. By bringing their tongues momentarily into contact with pollen during drinking, these bees suddenly changed their behaviour. They no longer looked for water at the drinking place but for the sweet material they had encountered. They returned to saucers of sugar syrup for days on end. These and complementary observations showed that the environment of the worker bee was extraordinarily limited. Her behaviour was primarily determined by habit.

International audience | I. — The period 1924-1927 has been marked out in the East of France by heavy attacks of Bupalus piniarius L. (Lepidopt. Geometridae) in the pine-forests of Haguenau and of Dasychira pudibunda L. (Lepidopt. Lymantriidae) in the broad-leaved forests. B. piniarius was particularly prejudicial.— Followed by Myelophilus piniperda (Coleopt. Ipidae), it determined, at Haguenau only, untimely fellings of 35.000 cubic-meters. II. — At the end of September 1927, a bacterium which contaminated the larvae of D. pudibunda, has been isolated. —This germ presented some resemblance with a bacillum, parasite on Schistocerca, isolated and described by D'HÉRELLE, and on which trials were made to destroy these Insects. The bacillum parasite on D. pudibunda larvae, interesting at a theorical point of view, seemed to be difficult to use practically. III. — In the forest of Haguenau, another way of destruction was adopted : an aircraft, loaded with pulverulent calcium arsenate, poured the poison on the crowns of the injured crops. — Inspite of the gropings impossible to avoid at the start of such a new method, this process, already employed abroad several times, seems apt for doing a good service.

In the F1 crosses, smut-infected plants yielded less than comparable smut-free plants, regardless of the location of the galls. This also was true with the inbred lines, except where the smut occurred in the tassel. In this case, there were only three pairs of comparable plants and the odds are only 3:1 that the difference was not due to chance. In 50 paired comparisons in the selfed lines, the smutted plants yielded 39% less than comparable smut-free plants and in 366 paired comparisons in the F1 crosses they yielded 50% less. Odds are sufficiently large so that these differences were not due to chance. These results are comparable to those obtained by some recent investigators (2) who obtained differences ranging from 7 to 94% in selfed lines, using the same method. They are contrary to those obtained by others (1) who were unable to demonstrate any differences in yield, other than those due to barrenness, between smutted and smut-free plants in the F1 crosses between inbred lines. Here the two plants compared were separated by not more than three hills. Whether or not similar differences would be obtained under other environmental conditions has not been determined. The differences in yield in the F1 crosses probably approximate more nearly the condition in normal corn than do the differences in selfed lines, as the former are more nearly comparable in vigor.

Early in the process of soil formation, the pH of the A1 horizon of the soils in Illinois becomes 5.7, which seems to be a position of equilibrium between the accumulation of bases from the decay of organic matter and the loss of bases by leaching. This pH is maintained as long as the soil is able to support a good vegetative growth. It appears that a soil in this region which is productive must have been able to maintain surface pH of at least 5.7 in the virgin profile. The highest acidity which might be expected in the mature soils of this region under present environment is a pH of about 4.8. Differences in the rate of leaching were observed in immature soils. Soils developed on rolling well-drained topography were more acid throughout the profile than those developed on flat topography under poorly drained conditions. A significant difference was observed in the amount of leaching in two profiles of the same soil type differing only in the length of time they had been subjected to weathering. The pH of the Slick Spot profiles shows a good correlation with the texture, structure, and consistence characteristics as observed in the field and with replaceable sodium as determined in the laboratory. The above points lead to the conclusion that the reaction profile is a relatively stable soil character, and that it can be considered as an aid to the separation of soil types.

The nitrogen content of 99 plats, located at three different points in semi-arid western Kansas, was determined in 1916 and again in 1927 and 1928. The quantities of nitrogen found at both analyses, together with the treatments to which the plats have been subjected, are reported in this paper. These data would seem to indicate the following relative to the nitrogen changes taking place in these soils during this short period of time: 1. Very large losses of nitrogen may take place under certain conditions. 2. The principal factor governing the nitrogen balance for this period seems to have been the nitrogen content of the soil at the beginning of the period. A correlation coefficient of 0.64 +/- 0.04 was found between the original nitrogen content and changes taking place in the nitrogen content for the entire 99 plats, or for 38 similarly cropped plats the corresponding value was 0.747 +/- 0.048. 3. Of the various cropping systems compared, continuous small grain or alternate small grain and fallow seemed to be conducive of the smallest changes in nitrogen content. One year of grain and three years of fallow apparently induced very large losses. Sorghums (kafir and milo), either continuous or alternating with fallow, also caused relatively large losses. The data relative to the influence of the various rotations are less conclusive, being complicated by the influence of the nitrogen content of the soil at the beginning, but on the average the losses were much greater than for small grain alone and less than for the sorghums. Losses when stable manure was added in a rotation were very high in spite of the nitrogen added in the manure, but again the influence of the original nitrogen content was probably partially responsible for such heavy losses. 4. There are indications that when the nitrogen content of the soil in this region falls to approximately 0.1% the factors responsible for additions of nitrogen to the soil will counterbalance those tending to cause its removal, thereby establishing a nitrogen equilibrium near this level. The very important question is raised whether at such a low nitrogen level the soil will be able to supply an adequate quantity of soluble nitrogen to enable the maximum utilization of the available moisture.

1. The percentages of winterkilling of winter wheat plants determined on date of seeding test trials during three consecutive years, 1923 to 1925, inclusive, were found to vary, depending upon the date on which the seed was sown. For a series of seedings made on or close to August 15, August 31, September 21, October 6, and October 19, the percentage of winterhardiness followed in decreasing order the seedings of September 21, September 4, October 3, October 17, and August 5, respectively. 2. The root development of plants for the various dates of seeding is strikingly different. The plants from the first seeding, August 18, show the greatest development of fall root system, followed in order by plants of the second, third, fourth, and fifth seedings. New root development in the spring usually proceded from the crowns of the plant. The old fall roots as a rule do not continue active growth in the spring, but subsequent spring root development continues from the crown of the plant. 3. Winterkilling did not occur, as a rule, from the fracturing of the roots, but because of the fact that the plants were raised out of the soil. As a result of this raising of the plant, death resulted through desiccation. This is an important factor in the late dates of seeding. If the spring season is humid, the dislodged plants may form new roots and become reestablished in the soil and continue growth. 4. Plants grown in soil, with 10% moisture content lived through the winter better and recovered better in the spring than did plants grown in soil having 25 to 30% moisture content. 5. Grain yields for the three years, 1922 to 1924 inclusive, are directly correlated with the amount of winterkilling. A low percentage stand of plants in the spring and also grain yield are not always indicative of high percentage of winterkilling. Especially is this true for the late seedings, namely, October 5 and October 19. It is on these late seeding dates that the greatest "heaving" of plants results which leads to plant desiccation. Therefore, death of plants in many of these instances is due to spring desiccation and not to actual winterkilling.