468 Beard. — Reproduction in Animals and Plants. 
represent abortive eggs. It has now been proved that in the 
Infusorian conjugation abortive spores are invariably, and 
abortive gametes occasionally, formed. 
It also follows that the essential act of conjugation, apart 
from the spore-formation and other processes leading up to 
the formation of like gametes, is the same in both Protozoa 
and Metazoa 1 , i.e. the union of two like nuclei, not, as is often 
stated, two like half-nuclei. 
Finally, from all that has been adduced in the course of the 
discussion, it may be concluded that there is one universal 
law underlying all those processes (conjugation, fertilization), 
which are classed together as sexual in nature, and this law 
has been defined in the preceding pages. 
And in plants. 
