136 SECRETS OF ANIMAL LIFE 
to be compared, as Professor Brachet says, to a 
harlequin’s coat, composed of non-interchangeable 
pieces. For a part of an egg is often as good as the 
whole, in the early stages of development at least; 
and a relatively large piece of the ovum may 
often be cut off without doing the future embryo 
any harm. Besides the nutritive yolk, which the 
egg usually builds up from materials furnished by 
the parent, it elaborates, as M Fauré Fremiet 
has shown in a unique research, a variety of other 
chemical substances which are among the building- 
stones of future structures. And besides these 
bodies which the egg-cell makes for itself, there are 
often ab initio others, with weird names, such as 
mitochondria, which are regarded by many as 
definite inheritance-vehicles. 
Lying in the midst of the complex cell-substance, 
which often shows an intricate microscopic structure 
(reticular or otherwise), there is a nucleus—a mi- 
crocosm within a microcosm. For inside this nu- 
cleus there are all sorts of things, notably a definite 
number of readily stainable bodies or chromo- 
somes, which again may be resolved into beads of 
chromatin embedded on pieces of a transparent 
(jinin) ribbon. The number of these chromosomes 
is definite, e.g. 24 for mouse and lily, and each cell 
throughout the whole body usually adheres to the 
characteristic number. So each species, like the 
Beast, has its number. Some say that a white man 
has 47 and a white woman 48, anda negro only 22; 
but in case any political advantage be taken of this 
