Contribution to the quantitative aspects in medical research.

Both the advantages and dangers of fallacies in the quantitative approach are discussed, having Laplace's "...le bon sens réduit au calcul..." for motto. The general rules are briefly presented. Stressed is the prerequisite of prior thorough qualitative study of the topic at stake. The medical and mathematical ways of thinking are contrasted, stressed is the leading role of the former. The rebound effect of the quantitative study on the qualitative aspects is treated, with special regard to medical terminology. The necessity to distinguish physiological values and population data is emphasized. Some further aspects are briefly mentioned. The illustrative examples are from diverse terrains of Medicine. The leading role of the well-trained and disciplined medical cortex is stressed throughout.