The plasma is itself immortal and will in fact live forever,
provided only external circumstances are favorable.
Death is always said to be inherent in the nature of protoplasm. This
is not so. The plasm, as such, is immortal.
But a further complication of great importance affects the
reproduction and the rejuvenescence of these unicellular organisms;
this is the process of conjugation. Two separate cells, distinct
individuals, fuse together. Their protoplasmic bodies not only unite
but intermingle, and their nuclei do likewise; from two individuals
one results. A single cell is thus produced, and this divides. As a
rule this cell seems stronger than the single individual before the
union. The offspring of a double individual, originated in this way,
increase for some time parthenogenetically by simple fission without
conjugation, until at length a second conjugation takes place among
them. I cannot consider further the origin of this universally
important process of conjugation. I will only suggest that a kind of
conjugation may have existed from the very beginning and may have been
determined by the original method of reproduction, if such existed.
At any rate conjugation has been observed in very many plants and
animals, and is possibly universally present in the living world.
Pages:
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156