“…Spies (1946aSpies ( , 1946b claims that the doses the above authors employed were too small, and he has obtained moderate haematological responses in pernicious anaemia using the natural polyglutamates and also one synthetic diglutamate. Others (e.g., Sharp et al, 1947) have also obtained responses with natural conjugates. This requires further confirmation using synthetic conjugates, as it is of the greatest importance.…”