Cohnheim1 in his monograph on embolic processes, published in 1872, first clearly enunciated the theory that infarcts could occur only where there was no anastomosis between arteries. In his own words: "Alles nämlich hängt davon ab, ob hinter dem Pfropf, zwischen ihm und dem betreffenden Capillargebiet, noch ein arterieller Zweig abgeht, der mit einer anderen beliebigen Arterie in unmittelbarer Continuität steht, also eine echte Collaterale oder richtiger gesagt, Anastomose bildet, oder ob eine solche fehlt." He thus impressed the medical world with the idea that unless "end-arteries" supplied an organ, or part of an organ, no infarction could occur. He made little reference to the brain, but in one place said that emboli in the brain usually cause simple necrosis, while in the spleen and lung the infarcts are usually hemorrhagic ("hämoptoische").
In spite of anatomic studies which have clearly shown the presence of anastomosis between the different arteries