“…Numerous electron microscopic studies have been published on the pancreatic islets in a variety of animal species, but those on the normal human islets are relatively few (YOKOH, IIZUKA and KANO, 1959;EKHOLM and EDLUND, 1959;GUSEK andKRACHT, 1959, 1961;ZAGURY, BRUX, ANCLA and LEGER, 1961;LACY, 1961LACY, , 1964LAZARUS and YOLK, 1962;BENCOSME, ALLEN and LATTA, 1963;GREIDER, ELLIOTT and ZOLLINGER, 1963;GREIDER and ELLIOTT 1964;BJORKMAN, HELLERSTROM, HELLMAN and PETERSSON 1966; on human fetus: SCHULTRICH, 1966 andLIKE, 1967). Among these authors LAZARUS and YOLK, GREIDER and ELLIOTT and BENCOSME, ALLEN and LATTA used biopsy materials taken from the uninvolved areas around pancreatic tumors.…”