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The numbers of lipolytic bacteria in various dairy products, as determined with Nile-blue sulfate
1934
Hammer, Bernard W. (Bernard Wernick) | Collins, M. A.
Studies in mineral metabolism XXIX. The iodine content of foodstuffs in relation to the occurrence of endemic goitre in the Langkloof Valley Texte intégral
1934
Iodine was determined in foodstuffs from different parts of South Africa including those from endemic goitre areas in the Uniondale district, and such widely differing results were obtained that no fixed relationship could be established between the iodine content of foodstuffs and the incidence of goitre.
Afficher plus [+] Moins [-]Testing the Crêpage of Yarns Before Weaving Texte intégral
1934
Saxl, Irving J.
In view of the importance of investigating the crêpage of individual yarns before their going into production, a new apparatus has been designed with which the crêpage of yarn samples can be determined previous to their being woven into cloth. By the contraction of the yarn, a drum is rotated and a pointer attached to the drum directly indicates the shrinkage of the sample. For bringing the yarn into contact with the solution, under uniform conditions, the latter is heated electrically and the temperature is controlled thermostatically.
Afficher plus [+] Moins [-]Physiological acidity and alkalinity of inorganic nitrogenous compounds in solution cultures Texte intégral
1934
Conrad, J.P.
1. The experimental procedure included complete utilization of the nitrogen in the single salt solutions by the sorghum and maize seedlings used. Simultaneous comparisons were made between parallel solution cultures. Typical comparisons included NH4Cl vs. HCl, NaNO3 vs. NaHCO3, etc. Titrable acidity of the solutions before and after absorption and the pH values of the dried and ground plants after absorption were determined. 2. Parallel cultures of (NH4)2SO4 vs. H2SO4 and of NH4Cl vs. HCl gave residual titrable acidity in each case after the disappearance of the NH4 ions from the cultural solutions. The residual liquids from the ammonium salts showed a greater amount of acidity than did those where the acid was supplied chemically. The pH determinations of the ground material showed that the acids absorbed or physiologically formed within tbe plants were still in evidence. Parallel cultures of NaNO3 vs. NaHCO3 and KNO3 vs. KHCO3 gave residual titrable alkalinity in each case after the disappearance of NO3 ions from the cultural solutions. The residual liquids from the nitrate salts gave smaller amounts of alkalinity in each comparison. The alkalinity absorbed or physiologically formed in each case was clearly shown as still present by the pH determinations of the ground plants. 4. Parallel cultures in solutions of HNO3, NH4NO3, NH4HCO3, and H2O after absorption of all NH4 and NO3 ions gave small amounts of titrable alkalinity in each case. These titration values were practically equal to each other, although the original solutions of HNO3 had marked titrable acidity and those of NH4HCO, marked titrable alkalinity. The pH values determined on the plants from the nitrogen compounds furnished in this group were practically equal to those on the plants grown in water. This showed that the acidity and alkalinity absorbed by plants in this group had largely disappeared in the transformations following absorption. These findings are in accord with theories previously proposed. 5. The plants must use energy in forming proteins from NH4 and NO3 compounds. The amounts of energy required to secure OH ions to go with the NH4 ions and of H ions to go with NO3 ions seem to bear a qualitative relationship to the rates of NH4 and NO3 ion absorption from solutions of different pH values.
Afficher plus [+] Moins [-]Technics and civilization
1934
Mumford, Lewis
'Technics and Civilization' first presented its compelling history of the machine and critical study of its effects on civilization in 1934 -- before television, the personal computer, and the Internet. Drawing upon art, science, philosophy, and the history of culture, Lewis Mumford explained the origin of the machine age and traced its social results, asserting that the development of modern technology had its roots in the Middle Ages rather than the Industrial Revolution. Mumford sagely argued that it was the moral, economic, and political choices we made, not the machines that we used, that determined our then industrially driven economy. Equal parts powerful history and polemic criticism, 'Technics and Civilization' was the first comprehensive attempt in English to portray the development of the machine age over the last thousand years -- and to predict the pull the technological still holds over us today.
Afficher plus [+] Moins [-]A chemical study of a soil under long-continued field experiments Texte intégral
1934
Snider, H.J.
The application of relatively large quantities of superphosphate, rock phosphate, and basic slag over a long period of years created in the surface soil a large supply of residual phosphorus. The phosphorus applied to the soil in the form of rock phosphate had at the end of a 27-year period a much higher solubility than superphosphate or basic slag phosphate. The penetration of applied phosphorus into the subsurface soil might be said to be negligible on the soil under consideration. Eight tons of lime increased the solubility of the native phosphorus in the soil, while 3 tons of limestone applied over a relatively short period of years had but little effect on the solubility of the native phosphorus. The Neubauer values indicated that the 8 tons of lime depressed the availability of rock phosphate and increased the availability of superphosphate and slag phosphate. This soil was low in replaceable potassium and the Neubauer method showed it to be low in available potassium, although it is relatively high in total potassium. The 8 tons of lime depressed the availability of potassium as determined by the Neubauer method, and tended to give lower values for replaceable potassium as determined by the chemical method. The reaction of the untreated soil was pH 5.0. The soil to which 8 tons of lime were added had a pH ranging from 6.3 to 7.0 and where 3 tons of lime had been applied the pH ranged from 5.9 to 6.3. The various phosphates caused some variation in soil reaction. The lime applications increased the replaceable calcium values. The heavy lime treatment showed little, if any, increase in replaceable magnesium, while light lime maintained the replaceable magnesium values considerably above that of the untreated check. The total nitrogen and organic matter values were maintained at a slightly higher level on the soils with the light application of lime as compared with the heavy application. The wheat grain yields and the total phosphorus content of the grain from the unphosphated plats coincided with the phosphorus solubility values of the soils from these plats. The phosphorus content of the second year spring growth of sweet clover indicated that the heavy liming apparently aided the assimilation of phosphorus from superphosphate and basic slag and tended to depress the assimilation of phosphorus from rock phosphate.
Afficher plus [+] Moins [-]Earliness in northern corn as affected by phosphate fertilizers, manure, and other soil treatments Texte intégral
1934
Olson, P.J. | Walster, H.L.
The comparative maturity of corn was studied during an 8-year period on plats receiving various soil treatments. Phosphorus advanced maturity significantly. During 3 of the 8 years when the date on which plants silked in the various plats was determined, it was found that phosphorus had advanced silking about 2 days. The combination of manure and phosphorus advanced the silking date about 3 days during this period. Lime or potassium did not influence maturity consistently. Manure advanced maturity somewhat. During 3 consecutive years that date of silking was noted, the crop was definitely advanced on the manured plats. The differences during the other years were of a low order in the majority of cases. The correlation between yield rank and maturity rank was low. The increased maturity of the crop was not sufficient in degree to warrant, by itself, the application of phosphorus. However, the increased yield of corn, wheat, and oats, all of which was a credit to phosphorus since the application was made only once during a rotation period including these crops, was apparently sufficient to cover the cost of application. The enhanced maturity, therefore, essentially represented the margin of profit from the soil treatment.
Afficher plus [+] Moins [-]Border rows of oat plats as affecting yields and variability Texte intégral
1934
McClelland, C.K.
It is clearly shown that the inclusion of border rows in plat yields when exact areas are considered gives an exaggerated yield, varying from about 4 to 8% from that obtained from interior rows, with higher percentages when wider alleys accompany narrow plats. The yield of first borders showed increases varying from 18.4 to 54.0%, the larger increases being due to wider alleys. The yields of second borders showed variations from -- 5.2 to 8% and were significant in only one case, that with 8-inch alleys in 1930. The inclusion of the alley area with the occupied area changes the yields as determined from all rows from an exaggerated yield into one usually significantly below that obtained from the interior rows. Inclusion of border rows of variety tests of winter grain caused greater variability than in tests where but one variety was concerned. There was less difference with spring oats varieties. The use of wide alleys caused greater variation in the first border rows and added to the inaccuracy of the results. The data are of value as an indication of the accuracy of the work in cases where insufficient help is available to harvest border rows.
Afficher plus [+] Moins [-]The effect of some forms of nitrogen on the growth and nitrogen content of wheat and rice plants Texte intégral
1934
Thélin, G. | Beaumont, A.B.
Varieties of wheat and lowland rice were grown in complete nutrient solutions supplied with different chemical forms of nitrogen. Sodium nitrate, ammonium sulfate, and urea and combinations of sodium nitrate and ammonium sulfate to furnish nitric and ammoniacal nitrogen in the ratios of 1 to 3, 2 to 2, and 3 to 1 were used to supply chemically equivalent amounts of nitrogen. The plants were harvested in three growth stages and dry weight of plants and certain nitrogen fractions in the plants were determined. Both species of cereals assimilated all forms of nitrogen to a certain extent. On the whole, rice was more at home with ammonium sulfate than was wheat. Both kinds of plants assimilated nitrogen from ammonium sulfate better in the early stages than in the later stages of growth. The best growth of rice in all stages of growth was obtained with the 3 to 1 ratio of nitric and ammoniacal nitrogen and of wheat with the same ratio except that in the second stage urea gave the greatest weight. Toxicity of ammonium sulfate was more pronounced with wheat than with rice, and this toxicity increased with the age of the plant. The toxic effect rather closely paralleled the amount of ammoniacal nitrogen found in the plants. Rice exhibited a much higher iron requirement than did wheat.
Afficher plus [+] Moins [-]The immunization of horses and mules against horsesickness by means of the neurotropic virus of mice and guinea pigs Texte intégral
1934
Details of the results obtained from the injection of horses and mules with neurotropic mouse and guinea pig adapted virus are given. It is shown that the virulence of horsesickness virus progressively decreases for equines as neurotropic fixation takes place by serial passage through mice and guinea-pigs. The attenuation occurs more rapidly through the guinea-pig, but it is not known whether the ultimate level will not be the same. All animals which survive an injection of one infective dose of neurotropic virus, whether or not a demonstrable reaction is produced, are immune to the homologous strain of virus. Immunity to heterologous strains is at most only partial. No difference in favour of either the subcutaneous or intravenous method of injection could be determined. It is shown that the subcutaneous injection of as small a dose as 10 c.c. of a 1:10,000 dilution of infective brain emulsion is adequate. Attention is directed to the phenomenon of a high concentration of infective guinea-pig brain emulsion producing a milder reaction than a low but still infective concentration. The possibility of developing a polyvalent vaccine is discussed.
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