584 The American Naturalist. [July, i 
the number 5 is the predominating one, in others 6, or another 
amount in the parts of the calyx as well, as in the petala, 
stamina, stigmata and carpella. Perfect symmetry in the ar- 
rangement and division of organs also is frequently found in 
plants and beautifully exhibited in many forms of ferns. 
Pursuing the enforcing faculty, the impulse or will in ani- 
mals or plants to conduct the formation of organs in certain 
unvariable ways, independent from external influences, we 
find it concealed in the minute embryo from which all creat- 
ures originate. But we have to admit at the same time, that 
the researches hitherto performed on this subject were but lit- 
tle successful, inasmuch as our knowleege in this respect is not 
much beyond that of our predecessors a century ago. They 
knew as well as we, that it is the germ or embryo, which is 
endowed with this power. The only apparent progress made 
is a hypothetical one, and consists in the prevailing opinion 
that in germination and growing, two different kinds of cells 
are active, some of them, the vegetative cells, being chiefly en- 
gaged in nutrition and growth, the others, or reproducing cells, 
for transferring to young individuals and preserving the char- 
acter of the parents, family, tribe, etc. It is upon the presence 
of this last kind of cells—most frequent in reproductive organs 
—that the resemblance in members of families and nations 
and of genera and classes is believed to depend. Scientists 
attribute the reproductive faculty to the nucleus of proto- 
plasma or albuminous matter found in these cells. 
The growth of cells is a limited one. When a certain store 
of food has been taken up and a certain amount of protoplasma 
has been formed, the latter, forming the kernel or nucleus of the 
cell, receives a gradually increasing stricture, dividing it into 
two halves, which finally separate; the stricture extends to the 
whole cell, which by division gives rise to two new cells per- 
fectly resembling the mother cell as to form, organization and 
general characters.. In this way multiplication of all repro- 
ducing cells takes place, including that of micro-organisms ; it 
is the simplest and primitive way of generation of new individ- 
uals. We see, that the progress of our knowledge in this 
question is limited to the fact, that while formerly the embryo 
