Heredity : with preludes on current events / by Joseph Cook.
- Josephus Flavius Cook
- Date:
- 1882
Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)
Credit: Heredity : with preludes on current events / by Joseph Cook. Source: Wellcome Collection.
155/208 page 147
![IDENTITY OF PARENT AND OFFSPRING. 147 their own explanation. While we listen only to facts which speak for themselves, we are on firm ground, 1. Many of the physical organisms of the lower forms of life propagate themselves by self-division. 2. In a self-divided organism there is in the two halves phj'sical identity. Suppose that we have here [drawing a figure on the blackboard] what Häckel calls a Moneron, one of the lowest types of life, an animal of irregular shape, a mass of protoplasm. It moves. It feeds itself. It grows. It has life. After it has grown to its natural size, it constricts itself in the mid^dle [illustrating on the blackboard], and finally falls into two portions. Self-division like this is the simplest form of self- multiplication of organisms. There appears to be con¬ cerned here just that mysterious property which aliving mass of bioplasm exhibits when we see it under the microscope throw out a promontory, which becomes de¬ tached at last, and then, as it takes up nutriment, goes on enlarging according to the law which governs its parent. The supposition is that the mass of bioplasm is homogeneous, or of the same qualities throughout. The promontory it projects will be physically of the same qualities with the parent mass ! When that promontory breaks ofi*, there will be in the island the qualities it had as a promontory. Therefore, between the island and the original mass there will be physical identity. So when an organism, consisting of a homo¬ geneous mass of bioplasm, multiplies itself by self- division, the original organism and the subdivided halves are related to each other by physical identity. 3. In a self-divided organism, physical identity is transmitted by hereditary descent. Here begins, but here by no means, as Häckel thinks, ends, the explanation of the law that like breeds like. Two yet greater facts are equally de¬ monstrable with the three already mentioned :— 4. The co-ordinating powers governing the move¬ ments of the two halves are also identical.](https://iiif.wellcomecollection.org/image/b18030051_0156.JP2/full/800%2C/0/default.jpg)
