188 NEUTRON EFFECTS ON ANIMALS 



activity, disorganization and atrophy of the germinal epithelium without 

 apparent injury to the Sertoli cells. The shrunken tubules became sur- 

 rounded by edema fluid in which the interstitial cells remained unaffected. 

 The degree of injury, judged b}^ histological changes and breeding experi- 

 ments, was proportional to the dose, and the time required for recovery was 

 proportional to the dose. 



The testicular changes following exposure to neutron radiation were the 

 same as those reported following X-rays and gamma radiation. 



Neutron irradiation of the white rat was followed by prompt reduction 

 in the size of the spleen and injury to the lymphoid tissue of this organ. 

 The degree of injury depended on the size of the dose. Recovery of the 

 spleen to an approximately normal status occurred after all doses, including 

 the maximum dose of 113 n. 



The livers and kidneys were found to be unaffected by neutron radiation 

 so far as could be determined by histological examinations. 



Femur marrow reacted to neutron radiation by a temporary decrease 

 in the number of megakaryocytes and cells of the granulocytic series, a 

 widening of the sinuses and infiltration of fatty tissue. 



REFERENCES 



(1) Lawrence, J. H., and Tennant, R., J. Exvtl. Med., 66, 667 (1937). 



(2) Yamashita, H., Gann, 31, 629, German Abstract, 654 (1937). 



(3) Yamashita, H., Nature, 141, 416 (1938). 



(4) Enns, T., Terrill, H. M., and Garner, J. M., Jr., Chapter 3. 



(5) Moore, Carl R., in "Sex and Internal Secretions", edited by Allen, Danforth, 



and Doisy, 2nd Ed., p. 367, Williams and Wilkins Company, Baltimore, 1939. 



(6) Mason, K. E., J. Exptl. Zool, 55, 101 (1930). 



(7) Ely, J. O., and Ross, M. H., Chapter 17. 



(8) Ross, M. H., AND Ely, J. O., Chapter 18. 



(9) Chrom, Sv. a., Acta Radiol, 16, 641 (1935). 



Since this book went to press, two articles have appeared describing the pathologic 

 changes resulting from products of Atomic Fission at Hiroshima, Nagasaki and 

 Bikini. That of LeRoy ("The Medical Sequelae of the Atomic Bomb Explosion", 

 J. Am. Med. Assoc, 134, 1143, 1947) shows photographs of the various organs, spleen, 

 testis, bone marrow, etc., which seem identical with our photographs shown above 

 and produced by neutrons alone. He states, "The proper objectives in the treatment 

 of patients who have been exposed to the amount of gamma radiation emitted by an 

 exploding atomic bomb are quite clear". It should be noted that the effects shown 

 in our photographs were produced by neutrons alone while the gamma radiation was 

 screened out by 3 inches of lead (see Chapter 3), so that to claim that the lesions 

 produced were by gamma radiation is without proof. Tullis and Warren ("Gross 

 Autopsy Observations in the Animals Exposed at Bikini", J. Am. Med. Assoc, 134, 

 1155, 1947) also show photographs of pathologic lesions produced by "ionizing radia- 

 tions" which seem identical with those produced by us by neutrons alone and when 

 shielded from gamma radiation. All this does not mean that neutrons are the sole 

 cause, but that they can possibly be the chief culprit, for we have been impressed 

 with the much greater effect of neutrons than of gamma and X-radiation which we 

 have studied previously since 1932. 



Ellice McDonald 



