APPENDIX. 
129 
Weismann supposes that the idioplasm of the nucleus governs 
the rest of the cell by the ids breaking up into their constituent 
biophors, which pass through the pores of the nuclear membrane 
into the cell body, and so work upon the crude sap which is 
absorbed into the cells as to convert it into protoplasm like them- 
selves. He assumes that during development the idioplasm, 
being handed on from cell to cell (as we know it to be), is 
gradually disintegrated into smaller and smaller groups, until 
finally only one kind of determinant is contained in the cell, viz., 
that which has to determine it. At each stage of this breaking 
up, certain and particular determinants are given off and broken 
up into biophors, but only just sufficient are so given off to do the 
work required as development proceeds. That is to say, certain 
of the determinants remain in an inactive condition until the time 
comes for them to do their work. It is like a contractor, who, in 
building a house, keeps the bulk of his capital in the bank, only 
drawing out sufficient every week to pay for the work as it 
proceeds. If he paid all his money the first week to the men 
who laid the foundations, the men would of course go on the 
spree, and no more work would be done. This metaphor of the 
contractor is not quite exact, however. To make it so we should 
have to suppose that certain kinds of money only could buy 
excavating, and stonework, and carpenters’ work, and plumbers’ 
work, and plasterers’ work, and pamters’ work, and so on, and 
we should have to suppose further that the contractor had his 
different kinds of money so arranged that they could only be got 
at in exactly the order in which they would be required. 
But if the idioplasm is all used up in building the body, how 
is new idioplasm to be obtained when a new body has to be 
formed at the next generation, or when the old one has to be 
repaired in case of accident ? The answer is that the idioplasm 
is not all used up, but a certain amount of it is preserved in an 
inactive or latent condition (as if it were money sealed up in a 
purse), and handed on from cell to cell until it reaches the place 
where the germ cells of the succeeding generation are to be found, 
when it is handed over to the new generation. This theory is 
called by Weismann the continuity of the germ plasm. The ids 
of which this latent germ plasm is composed are, moreover, 
capable of growing and multiplying without thereby becoming 
active or breaking up. Under certain abnormal circumstances 
certain of them are capable of becoming active, as it were, before 
their usual time, as when a cutting of a plant emits roots, although 
the ordinary root determinants had presumably passed into the 
roots of the plant when its first roots were formed. 
We now come to another very important question, viz., What 
is the object of fertilisation, or, as Weismann calls it, Amphimixis ? 
