Probleme der chemischen Bekämpfung schädlicher Tiere im Walde
Spraying Toxaphen against mice in forest cultures seems to be doubtful on the strength of side effects. The effectiveness of toxic baits for mice control should be increased by raising attractiveness as well as by reducing the size of baits. Experiments showed that Tetrachlorvinfos can be used forHylobius-control in place of DDT. Within young coniferous stands cleared by chemicals bark beetles can be controlled by felled stems sprayed with BHC. For avio chemic measures against larvae in the crowns of conifer the best results were obtained by using insecticides mixed with Diesel oil.
Waldschutz und DDT-Verbot
SummaryForest protection and ban on applying DDT
 The bans on applying DDT enacted by the governments of BRD an other States are founded politically but not scientifically, DDT is the best and most harmless insecticide we ever have had. Its accumulation within the fat body of animals and men for a certain time does not cause pathological symptoms. Some effects unfavourable to wildlife animals are consequences of incorrect application.In forest protection in Germany DDT is needed also in future for controlling the weevielHylobius abietis, the lepidoptersRhyacionia buoliana andChoristoneura murinana as well as the sawflies of genusDiprion. It is demanded of the legislator to prolong the use of DDT in these cases until equivalent insecticides have been found. Lindan (γ-BHC)-compounds are not suitable for controllingHylobius beetles.
Some additional notes on the kinetics and theory of fatty oil hydrogenation
Summary1.Equations are given for estimating from the composition of oil samples the relative reaction rates of the different unsaturated fatty acids in an oil subjected to catalytic hydrogenation.2.Application of the equations to data from the hydrogenation of cottonseed oil reveals that the ratio of reaction rates, linoleic acid to oleic acid, varies from about 4 to 1 in very non-selective to about 50 to 1 in very selective hydrogenation. Re-examination of analytical data on two series of linseed oils hydrogenated selectively and non-selectively showed the following relative reaction rates for oleic, isolinoleic (9: 10, 15: 16 octadecadienoic), linoleic, and linolenic acids, respectively: non-selective, 1, 2.5, 7.5, 12.5; selective, 1, 3.85, 31, 77. In the non-selective hydrogenation of the oil, 24% of the linolenic acid reacting went to linoleic acid, 65% to isolinoleic acid, and 11% directly to oleic acid. In the selective reaction the corresponding figures were none to linoleic acid, 54% to isolinoleic acid, and 46% to oleic acid. The behavior of soybean oil hydrogenated selectively was quite similar to that of linseed oil.3.The results are discussed in relation to the theory of catalytic hydrogenation. They indicate that the solution of hydrogen in the oil and the adsorption of unsaturated oil on the catalyst are the two steps which are controlling with respect to the reaction rate. It is suggested that the hydrogen pressure, the degree of hydrogen dispersion through the oil, the catalyst concentration, and the temperature all affect the selectivity of the reaction through their influence on the concentration of hydrogen in the reaction zone, with selectivity being favored by a low concentration.