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APPENDIX. 
complex units, and these again into still higher units, just as 
letters are built up into words, words into sentences, and sentences 
into books. 
Weismann divides up the body of an animal or plant into 
an immense number of spots or areas, which he calls determinates. 
A determinate is the smallest part of the body which is inde- 
pendently variable. In a Fern, for instance, a determinant must be 
something smaller than a pinna, because one part of a pinna may 
vary while another remains normal. In Moly’s pulcherrimum 
variety of P. angulare, for instance, the upper half of the pinna 
is frequently normal, while the lower half shows the pulcherrimum 
character. On an average, a determinate would perhaps corre- 
spond with a pinnule, though it may be smaller even than this. 
Each determinate has its character controlled or “determined” 
by a unit of idioplasm called a determinant, and which consists 
of a group of biophors. It is an independent vital unit, capable 
of multiplying, and having its constituent biophors built up in a 
particular order or arrangement. It has the same relation to a 
biophor that a molecule has to a chemical radical, or that a word 
has to a syllable. 
The id is a still more complex vital unit, consisting of a 
group of many determinants, which are again built up in a definite 
and systematic order. Every id of the germ plasm is supposed 
to contain the whole of the elements which are necessary for the 
development of all subsequent idic stages (i.e., stages of growth 
in an individual). If animals or plants existed (as not improbably 
they do) in the whole series of ancestors of which sexual repro- 
duction had never occurred, their ids would be exactly similar to 
each other. Weismann expresses the opinion that those rod-like, 
loop-like or granular masses of chromatin in the nucleus — the 
chromosomes — are to be considered not as single ids but as 
series or agglomerations of ids. In some cases, as in Ascaris 
megalocephala (a kind of parasitic worm), the chromosomes can 
be seen to be made up of spherical bodies, like little beads strung 
together, and it is these beads which are supposed to be the ids. 
But what have all these biophors and determinants and ids 
to do with heredity ? 1 am coming to this now. 
As I said before, it is a known fact that whenever a cell 
divides, the idioplasm of the nucleus divides with it and a portion 
passes into each daughter cell. It has also been long known 
that it is the nucleus of a cell which somehow governs its growth 
and character. If a one-celled organism be divided artificially 
in such a way that the whole of the nucleus is left in one part, 
the part which has no nucleus ceases to grow and soon dies, 
while the part containing the nucleus goes on growing and 
dividing as if nothing had happened. 
