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37. Reddy, B. S., and Pollard, M. Eifect of germfree 
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40. Pollard, M., and Sharon, N. Prevention and 
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43. Pollard, M., and Wagner, M. (Unpublished in- 
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45. Kajima, M., and Pollard, M. Virus-like particles 
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46. Gordon, H. A., Bruckner-Kardoss, E., and 
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tables and lesions observed at natural death. J. Ger- 
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47. Pollard, M. Senescence in germfree rats. Geron- 
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48. Wilson, R., Sjodin, K., and Bealmear, M. The 
absence of wasting in thymectomized germfree 
(Axenic) mice. Proc. Soc. Exp. Biol, and Med. 
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49. Wilson, R., and Bealmear, P. M. Radiation 
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51. Jones, J. M., Wilson, R., and Bealmear, P. M. 
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in germfree mouse radiation chimeras. Radiation 
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52. Pollard, M., Matsuzawa, T., and Salomon, J. C. 
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53. Pollard, M. Chemical induction of mammary 
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55. Pollard, M., and Sharon, N. Irradiation-induced 
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47:229-234, 1971. 
56. Pollard, M., Kajima, M., and Zacharia, T. P. 
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58. Pollard, M. (Unpublished information) 1971. 
DISCUSSION 
Stevan SiBiNOViC, Bionetics Research 
Lab. : I am interested in the question of mice 
with neoplasm development. More specifically, 
when you say that all three strains of mice ac- 
tually develop neoplasms. 
Dr. Pollard : They all have leukemia virus, 
but only one strain develops it spontaneously. 
The others have to be irradiated in order to 
elicit the disease. 
Dr. Sibinovic: On B strain, if you use 
chronic immunosuppressant, do you use it prior 
to development of the disease or do you stop the 
disease somewhere else ? 
Dr. Pollard : We have two papers published 
on this, one of them in the Journal of the Na- 
tional Cancer Institute, and the other in the 
Proceedings of the Society for Experimental 
Biology and Medicine. 
If we treated the mice that were sick with 
subtoxic doses of cyclophosphamide, we would 
prolong their life expectancy at least eight to 
nine times. And if we treated mice before they 
developed symptoms of the disease, we lost none 
of them; all of them surviving for thirteen 
