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Thirty anesthetized, male White Leghorn chickens, approximately six months old (average body weight, 2.030 ± 0.048 kg.), individually inhaled radioactively labeled (1-128) monodispersed latex particles. Six birds each were exposed to one of five particle sizes (0.091, 0.176, 0.312, 1.1, and 3.7 to 7 microns). During exposure, the respiratory rate and tidal volume were monitored by a whole-body plethysmograph. Inhaled aerosol was detected externally for each of seven, equal-length sections along the axis of the body. Percentages of deposition for each section were calculated from the corrected time-decay activity.Significant differences (P < 0.05) were found for regional deposition as a function of particle size. The largest particles (3.7 to 7 |x.) were captured in the head and anterior trachea; other particles were deposited uniformly throughout the remainder of the system. The 1.1-micron-size particles were deposited primarily in the lung and posterior air sacs; those of 0.312-microns (having weak interception, impaction, and diffusion-capture mechanisms) tended to pass through the posterior to the anterior sacs (assuming the Hazelhoff-Bethe gas pathway theory); and smallest particles, influenced by diffusion, were captured in the birds' caudal regions.

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Effects of heat and estrous cycle on food and water intake and on the kinetics of water metabolism were studied in Holtzmann rats, 12 adult females per group. The animals were housed individually in metabolic cages, in series, in a controlled-environment room at (24.5 degrees C) followed by two experimental temperatures (29.2 degrees C and 34.0 degrees C). In all cases relative humidity was 50% and the photoperiod 12L:12D (L = 0600--1800 h). Intake of food and water, available ad libitum, were measured and recorded daily for at least five consecutive estrous cycle (about 25 days). Water turnover was measured using tritiated water. The results indicate that the experimental conditions constituted stressful environments for the rats. Their corticosterone levels were significantly (P less than 0.01) elevated and a relative lymphopenia and neutrophilia (P less than 0.01) were observed. Additionally, food intake was decreased and water intake increased, both significantly (P less than 0.01). Body water turnover was increased (P less than 0.01) while body water pool size and the biological half-life for 3H2O were reduced. However, the cyclic variation of food and water intake and its relationhsip to the estrous cycle were unchanged.