Document EmjYb4V7a52N67vVqb6XokDXV

9*tduihud BIO-TIST laioiatoMei, Dnc. 1810 FRONTAGE ROAD NORTHBROOK. ILLINOIS 60062 aia coos Jia eiEPHONS 3T3- 3030 May 23, 1969 MAY i; 6 1969 Mr. Elmer P. Wheeler Monsanto Company 800 N. Lindbergh Boulevard St. Louis, Missouri 63166 Dear Elmer: It Is our opinion that the addition of 15/15 rats per group to the chronic Aroclor studies in rats can be justified to provide some information prior to completion of the two-year study and to give some basis for possible changes in dose levels as the chronic study proceeds. The addition of this number of animals would permit sacrifice of 5/5 animals per group after 90 days, six months and one year. All animals from the high dose level groups and controls would be sub jected to histopathological examination with follow-up at lower levels in case of positive findings. Additional hematological and clinical studies would not be required. The cost of the addition of 300 animals to the rat study would be $12,000. A similar increase in the dog study would be difficult to justify economi cally and no purpose would be served by increasing the number of animals in the chicken, duck and reproduction studies. We will await your instructions. With best regards. Sincerely yours, OEF:psh Otis E. Fancher, Ph. D. Director MQNS 090111