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This paper describes the use of fluorescent materials for tracing insecticides in soil. The mixing of insecticide dusts with dry, finely sieved soil in the laboratory has shown that the concentrations of a toxic chemical available to a soil insect will vary greatly according to the depth of soil with which it has been thoroughly mixed. The state of the soil also affects the distribution of the material; if the soil is dry it can be evenly distributed, though frequently it is not. When the soil is damp and has a fine crumb structure, a dust becomes distributed on the outside of the individual crumbs. Subsequent mixing of the soil distributes the contaminated crumbs throughout the mass, but this does not result in transfer of the dust to other crumbs; the result is uneven distribution.

Observation of small particles in positive columns shows that considerable interaction can occur between and the plasma. This paper suggest methods for analysing the complex situations which may arise and discusses some simplified cases, illustrated by reference to discharges in argon at about 1 torr. Ordinary positive column theory can be modified to allow for presence of cold particles by treating them as distributed insulated negative surface ionization sinks, additional tot he wall sink if their effect is relatively small, and replacing it if their effect is large. Increases in electron temperature and axial field result and the radial electron concentration pattern may be altered, an off-centre maximum developing under some conditions if the particles are concentrated near the axis. Dust-laden discharges may be noisy. The particle temperature will usually exceed the gas temperature because of the surface recombination. Equilibrium temperature are obtained by equating the recombination heat to the sum of the radiation and gas-cooling losses. The temperature lag which occurs when plasma parameters alter near a particle is also discussed. The tendency of the particles, like massive negative ions, to congregate near the axis stagnant gas is accounted for as an effect of the radial electric field, modified substantially in some instances by the dust. When the electron concentrating is large, for example in the core of a constricted column, particles may heat sufficiently to become thermionic emitters, and evaporate and recondense farther out, or react rapidly chemically. The accompanying local heating and distortion of the plasma is one of several possible causes of gas turbulence in which the particles can participate. In strongly inhomogeneous discharges, differential ion pressure may contribute significantly to the particle dynamics.
The main results obtained for positive column theory ( 2), particle temperatures ( 3), and particle dynamics (<... [ABSTRACT FROM AUTHOR]

The section of "A Critical Appreciation of Recent Developments" focuses on the textile industry's actions which are directed towards environmental hazards. It is reported that noise levels depend largely on the design of the spinning room. It is further stated that operatives are not to be consistently exposed, over long periods, to a noise-emission level higher than 90 dBA. It is stated that the dust is common to the manufacturing of fibres. It is further informed that the dust problem in cotton-processing has been linked to the industrial diesease of byssinosis.

The ventilatory functions (forced vital capacity, forced expiratory volume in one second, and peak expiratory flow rate) of West Pakistani immigrants working near Manchester were measured. There were 198 `normal' healthy adult workers aged 25 to 60 years and 129 workers aged 16 to 24 years. The subjects were considered `normal' if they did not admit to persistent cough and phlegm. The regression equations on age and height for the two groups are presented together with the corresponding nomograms for the adult group. Ventilatory function reached its maximum between the ages of 25 and 30 years; smokers and dust-exposed subjects did not differ significantly from non-smokers and non-dust-exposed subjects (P>0·1). This was probably due to their relatively light smoking habits and the short duration of dust exposure. The effects of age, in workers over the age of 25 years, and the predominant effects of height on the FVC, FEV, and PEFR are similar to those found in other studies. The ventilatory capacity of the subjects was found to be somewhat lower than that of Caucasians, about equal to that of Negroes living in America, and higher than that of Indians of Asian origin living in Guyana or of Bantu Negroes in South Africa. The predicted FEV/FVC% in the West Pakistani subjects is a little higher than any calculated from the results of other authors, but its regression on age is consistent with the findings of other studies and, therefore, can be used in clinical practice to assess the pulmonary conductance. [ABSTRACT FROM PUBLISHER]

The postnatal growth of the pre-acinar or conducting airways of the lung was examined by measuring the dimensions of selected axial pathways in lungs at different stages of development. The material included both formalin-fixed specimens and bronchograms. A method of comparing the relative sizes of each part of the pathways was developed which allowed for differences between the number of branches or generations measured in each specimen. The results indicate that the pre-acinar airways of the infant may be regarded as a miniature version of those in the adult and that this relationship persists during postnatal growth. Each individual branch grows in a symmetrical fashion both in length and in diameter and bears a constant relation to the whole. The physiological function of the conducting airways during growth was investigated using published data on the breathing pattern of infants. Particular attention was given to the conditions of airflow, to the warming and humidification of inhaled air, and to the filtration of airborne dust. [ABSTRACT FROM PUBLISHER]

Fifty-four opium smokers with chronic obstructive lung disease were studied for two-and-a-half years. Forty-eight patients had a cough for at least two years before the onset of inappropriate exertional dyspnoea. Fine, bubbling adventitious sounds suggesting small airway disease were heard on auscultation over the middle and lower lobes in 38 patients. The prevalence of inflammatory lung disease and chronic respiratory failure in this series is suggested as the main cause for the frequent finding of right ventricular hypertrophy and congestive heart failure. Physiological studies revealed moderate to severe airways obstruction with gross over-inflation and, in 32 patients, an additional restrictive defect probably due to peribronchiolar fibrosis. Radiological evidence of chronic bronchitis and bronchiolitis was observed in 45 patients, `pure' chronic bronchiolitis in six patients, and `widespread' emphysema in 25 patients respectively. Necropsy examinations in nine patients, however, showed destructive emphysema of variable severity in all. Chronic bronchiolitis often associated with striking bronchiolectasis was present in six cases. More severe bronchiolar rather than bronchial inflammation was noted. The heavy opium smokers had characteristic nodular shadows on chest radiography, sometimes associated with a striking reticular pattern not seen in `pure' cigarette smokers. This was due to gross pigmented dust (presumably carbon) deposition in relation to blood vessels, lymphatics, and bronchioles, and also within the alveoli. It is speculated that the initial lesion is an acquired bronchiolitis. Opium smoking induces an irritative bronchopathy favouring repeated attacks of acute bronchiolitis and eventually resulting in obliterative bronchiolitis, peribronchiolar fibrosis, chronic bronchitis, and destructive emphysema. [ABSTRACT FROM PUBLISHER]

This article presents information on chimney-sweepers. In the sixteenth and seventeenth centuries the trade or mystery of chimney-sweeping was carried on in England, as in other European countries, by men who stood in the cavernous chimneys and swept the light soot deposit from the sides with birch brooms affixed to long poles, or who climbed ladders in especially lofty chimneys and used short-bandied brushes. A chimney-sweeper on the roof would lower a rope, weighted with an iron ball, down a flue to his companion waiting on the hearth. The latter would pull on the rope until a bunch of furze or broom, tied to the center, appeared; then, turning the bunch with the twigs uppermost, he would signal to his fellow to haul it up. The twigs, scraping the sides of the flue as they were pulled up and down several times, would dislodge the soot. Instead, however, of employing two grown men to clean their tortuous flues, householders in England began early in the eighteenth century to transform small children into human brooms for sweeping out their flues, which were easily clogged by soot from coal fires.