weismann's demarkation between germ-line and soma rested on the work of (mostly) german biologists during the second half of the 19th century. this was the time that the mechanisms of cell division began to be understood. eduard strasburger, walther flemming, and the belgian edouard van beneden laid the basis for the cytology and cytogenetics of the 20th century. strasburger, the outstanding botanical physiologist of that century, coined the terms nucleus and cytoplasm. he said "new cell nuclei can only arise from the division of other cell nuclei". van beneden discovered how chromosomes combined at meiosis, during the production of gametes. walther flemming, the founder of cytogenetics, named mitosis, and pronounced "omne nucleus e nuclei" (which means the same as strasburger's dictum). the discovery of mitosis, meiosis and chromosomes is regarded as one of the 100 most important scientific discoveries of all times, and one of the 10 most important discoveries in cell biology.