Ionizing Radiation and the dose is small The effects of irradiation on living systems may be studied by looking for effects on the living cells, for changes m the biochemical reactions, for evidence of production of dis ease, or for changes m the life or normal growth patterns (Fig 44-4) Interpretation of such findings is not simple Extensive research m this field is continually being earned out in many laboratories The human body is composed largely of water and of other materials containing hy drogen, carbon, oxygen, nitrogen, and smaller amounts of other elements In human tissue, these elements are present in the proportion of about one nitrogen atom to twenty oxygen, to five carbon, and to forty-five hydrogen atoms It is therefore important to study the effects of radiation on water and on ma terials of a composition which resemble human bssue Irradiation of water produces large num bers of free electrons which have been ejected from the parent atoms, leaving positive ions In this process of ionization, there is dissocia tion of the water molecule and the release of oxidizing agents In the human body, there may be changes of structure of organic mole cules and changes in the biochemical proc esses Some of these same changes may be occurring independently of the radiation, so the mechanisms are complex and are being studied intensively Types of injuries The accumulation of knowledge of the effects of radiation on man was begun in 1895 when Roentgen discovered the X ray Radiation from uranium was discovered by Becquerel m 1896 Alpha, beta, and gamma rays were identified shortly thereafter, and the neutron was discovered m 1930 Injuri ous effects were experienced by these early workers m nuclear science As radiation was applied to man for healing purposes, effects such as skin redness, dermatitis, and skin cancer were noted, as were loss of hair and eye inflammation It was found that the incidence of cancer and of certain blood dis eases was higher among radiologists than would be expected for a chance distribution in the population studied The pool of health experience data was obtained from (a) early radiation workers.

V Industrial Health Section Decenber 1937 'LAINTIFF'S EXHIBIT MET-1058 Industri&1 Hygiene Laboratory Surreys of the .follesini plants ere utde during the ascth by aesbers of the Laboratory staff; florthem Eire Division Unicntoca, Pennsylvania W. 4 C.

204 junjxtr im ... 4ert, 4<atrj *U, 1936.

Yur 1933 1934 1953 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 AMERICAN BRAKKBLOK DIVISION SALK3 TO NAPA HONOLULU HEAVY DUTY THICK BLOCKS Cubic Inch** 7,600 82,200 95,900 150,600 248,600 213,600 198,900 231,800 133,400 134,200 182,162 167,195 90,297 Dollar* $ 466 5,356 6,253 9,860 16,263 14,577 13,075 14,668 8,428 8,386 11,387 10,340 5,779 1 Sailing Prica Par MCI $ 61.39 65.14 65.20 65.46 65.41 68.25 65.74 63.27 63.16 62.50 62.51 63.04 64.00 SCI 02136

TUMORS OF THE SKIN 137 Switzerland, Holland, Italy, Russia, Australia, New Jersey, New York, Penn sylvania, Illinois, Massachusetts, and Wisconsin).

`-:i of Eouioment I for Maintenance -. y,~v-: "- - -- - or IM IS* Vtf;y.

766 Twentieth Congress--National Safety Council Utfrchai-gc his duties.

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OCCUPATIONAL NEOPLASIA AND CANCERIGENESIS 817 McIntosh obtained in 1933 four tumors in fowls treated with tar, three of which could be propagated readily by filtrates prepared from the original neoplasms.

ABSTRACTS FROM CURRENT LITERATURE 329 In investigations covering hundreds of persons engaged in lead mining, lead smelting, etc., he confirmed the general observafions of Ferguson and Ferguson (1934) in regard to the ratio of large to small lymphoid cells.

(Imw f -Wftifr<. cun 4I4-4U * c**.

344 FRANK A.

234 CHAPTER 6 Not all cigarette companies were enthusiastic about the rise of German fascism.

360 BIBLIOGRAPHY Liek, Erwin.

Asbestos use faces further restrictions Although asbestos is one of the most heavily regulated materials used in commerce today, some federal agen cies maintain that it continues to be a hazard and they are making a con certed effort to restrict its use even further