Weismann cut off the tails of rats for about 22 generations but there was no reduction in the size of the tail. On the basis of this experiment, Weismann proposed the theory of the continuity of germplasm. According to Weismann,Two type of matters is present in organism, somatoplasm and germplasm. Somatoplasm in the somatic cells and germplasm in the germinal cell. Somatoplasm dies with the death of organisms while germplasm is transferred into the next generation.
If any variation develops in germplasm, it is inherited, while if variation develops in somatoplasm it is not transmitted. So, the correct answer is 'Weismann'