Dr. Cantril's Men: For Rockefeller From Mcclintock: Informs Very Dangerous For-, To Make Survey Of Catholic Church. Informs Landes In Beunos Aires Not At All Fitted To Make Such A Survey. Also Mail Being Sent In Open Mail On Very Confidential Subjects To These Men And Should Not Be Sent In Plain English But In State Dept. Code, And In Diplomatic Pouch For Safety.