Karl Landsteiner

“It is a peculiar and mysterious circumstance that the first experiments on the subject of blood transfusion in man were not made upon persons whose lives were in danger.”

“The serological reactions are on a par with the most delicate and specific chemical reactions, and we are justified in applying the term 'chemical' to them in a figurative sense.”

“The designation of the blood groups is not based on any essential differences in the blood of different human races.”

“The discovery of the blood groups, which has proved to be of such great importance in medicine, was not the result of a preconceived plan of research.”

“The differences between the blood of individuals are as characteristic as the differences in their fingerprints.”

“Thus, it may be expected that in the case of a transfusion from a person of one group to a person of another group, the serum of the recipient will agglutinate the corpuscles of the donor.”

“Besides the four main blood groups, a number of subgroups have been discovered.”