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Ammonia at levels of 0, 25 or 50 parts per million (p.p.m.) was introduced into 12 controlled-environment chambers containing male Leghorn chicks. Ammonia was introduced continuously into the test chambers from the 4th to 8th week of the experiment. An infectious bronchitis vaccination was administered to all chickens at 5 weeks of age. Body weights and feed efficiencies were determined at 4, 6 and 8 weeks of age. At 4, 5, 6 and 8 weeks of age lung and bursae of Fabricius weights, hematocrits and air sac scores were determined.Body weights and feed efficiencies were significantly reduced in the ammonia chambers. The bursae of Fabricius of the ammonia-stressed chickens were significantly larger than those of controls at 5 weeks of age and significantly smaller at 8 weeks of age. Chickens grown in ammoniated environments had significantly larger lungs at 8 weeks. Hematocrits were not significantly different among the treatments. Total air sac scores were significantly higher in the ammonia-stressed chickens at 8 weeks. Results indicated that chickens are affected by the stress of ammonia at levels of 25 or 50 p.p.m. and infectious bronchitis vaccination. ABSTRACTBlood plasma from non-laying turkey hens was subjected to size exclusion chromatography on columns of 2% Agarose gel. No material corresponding to either the low-density-fraction (LDF) of egg yolk or to phosvitin-lipovitellin complex was noted. After egg laying was initiated, two new phosphate containing peaks were observed in blood plasma. One was isolated by flotation in the ultracentrifuge (d < 1.006) and had a mean molecular weight of 4.48 x 10 6 . Egg yolk LDF, isolated by ultracentrifugation, had a mean molecular weight of 2.50 x 10 6 . Both the blood plasma and egg yolk LDF fractions had similar ratios of optical density (280 nm.): ng. phosphorus per ml. of column eluate and all of the phosphorus was extracted with organic solvents. The second phosphate containing peak (molecular weight 5.33 x 10 s ) was probably a phosphotin-lipovitellin complex as only part of the total phosphorus was extractable with organic solvents.

Workers were studied at a tannery that operated from 1873 to 1960, once one of the biggest in Scandinavia. The results show a slight numerical increase of deaths from cancer of the stomach and a significant, threefold excess mortality from cancer of the pancreas. Even in view of critical questions about validity it seems likely that this excess might be related to exposure to chemicals in tannery work.Work in tanneries may entail exposure to several chemicals for which there is evidence of carcinogenicity in people or laboratory animals or both.' Some surveys have suggested an association between working in leather industries and cancer of the lung, larynx, buccal cavity, pharynx, bladder, and lymphomas' and cancer of the kidney.1 2 A study dealing specifically with leather tanners and bladder cancer, however, showed no significantly increased risk of this disorder.3 Recently Pippard et al reported a study of the mortality of tanners in which no significant excess mortality was found for any of the common sites of cancer (stomach, large intestine, rectum, lung, prostate and bladder).4 In the light of the inconsistency between the various studies further information seems to be needed, and the present study was carried out on workers at a tannery in the south east of Sweden. The company had been in operation from 1873 to 1960, and in the 1940s it was one of the biggest in Scandinavia, with more than 600 people employed, producing mainly leather for shoe uppers. No other sizable industry operated in the area, most people being farmers or forestry workers or employed in associated services.The tanning operations were primarily carried out manually, but became more and more mechanised. The main method was chrome tanning, which was introduced at the beginning of the century but vegetable tanning also took place. Chrome tanning entailed exposure to trivalent and hexavalent chromium compounds and vegetable tanning to European chestnut, oak, and red quebracho. Some exposure to fungicides, especially chlorophenols, is also likely to have occurred as well, but the extent of the exposure is not known exactly. Nor are there any quantitative data available from hygienic measurements. Materials and methodsThe local register of deaths and burials, covering all people in the parish where the tannery was located, was used as the source of subjects for this study focusing on cancer deaths. Since cancer is rare in the younger age groups, the study was restricted to include only men aged 45 or more. This also allowed for a latent period thus increasing the likelihood of demonstrating a possible effect from long term occupational exposure.The study period was 1951-79 and the estimated background population for the parish was based on the average of the censuses from 1960, 1965, 1970, and 1975. Causes of death were classified in accordance with the 8th revision of the International Classification of Disease (ICD 1965). According to the principles for classification, only the underlying

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5 (1979) 10-151 has indicated a possible relationship between lung cancer and exposure to radon and radon daughters in dwellings. Indoor radon concentrations seem to depend on both building material and leakage of radon from the ground. This new study, in a rural area, is a further attempt to elucidate the etiology of lung cancer, taking into consideration type of house and ground conditions, as well as smoking habits. Although the choice of a rural study population helped to eliminate various confounding exposures in the urban environment, it limited the size of the study because of the rareness of lung cancer in rural populations. Long-term residents, 30 years or more in the same houses, were studied, and again an association was found between lung cancer and estimated exposure to radon and radon daughters in homes. The data also seem to indicate the possibility of a multiplicative effect between smoking and exposure to radon and radon daughters in homes, but there was also some confounding between these factors in the data.