... A bit later in the latter half of the 19th century, the German medical pathologist Rudolph Virchow stated positively that all cells, both animal and plant, came only from pre-existing cells though he was not sure how this came about. Then, about 1880, the process of mitosis was discovered, and the secret of how both plant and animal cells make exact duplicates of themselves was revealed.
Another very important scientist during the late 1880s and early 20th century was August Weismann, who died in 1914. Weismann was an avid supporter of Darwin’s theory of the evolution of species by means of natural selection. Prior to Darwin, the most widely-accepted theory of evolution was the one embracing the inheritance of acquired characters that was proposed by Jean Baptiste Lamarck in 1810.
Weismann set out to prove Lamarck’s theory was nonsense. For 14 generations, he cut the tails off mice and bred them. All of the offspring generated during the 14 generation period were born with tails, while their parents had been tailless.
Weismann said the body of an animal is made of two parts, the body cells or somatoplasm and the reproductive cells or the germplasm. He stressed that hereditary characters were passed on only through the germplasm. He pointed out that the somatoplasm died with each generation, but the germplasm was immortal, it went on forever. This is true.
Did you ever wonder where you came from? (...)
Though our body cells may die, our germplasm does not but lives forever if we do our biological duty and reproduce. In this simplistic sense, the physical side of man is truly immortal.