552 TWO PRINCIPAL MODES OF REPRODUCTION. 
CHAPTER XV. - 
OF REPRODUCTION. 
723, Tere is no one of the functions of living beings, that 
distinguishes them in a more striking and evident manner 
from the inert bodies which surround them, than the process 
of Reproduction. By this function, each race of Plants and 
Animals is perpetuated ; whilst the individuals composing it 
successively disappear from the face of the earth, by that 
death and decay which is the common lot of all.—A very un- 
necessary degree of mystery has been spread around this pro- 
cess. It has been regarded as one altogether inscrutable, 
whose real nature could not be unveiled, even by the scientific 
inquirer, and whose secrets the uninitiated should never seek 
to comprehend. But so much light has been thrown upon it 
by recent investigations, that we now know at least as much 
of this, as of almost any other function; and the Author's ex- 
perience has led him to believe that such knowledge may be 
communicated to the general reader, without the least in- 
fringement of the purest delicacy of feeling. In his own 
judgment, indeed, it is far better to afford a legitimate satis- 
faction to the curiosity which naturally exists upon the sub- 
ject, than, by refusing all information, to drive the inquirer 
into objectionable methods of gratifying it. 
724. It has been elsewhere shown (Vucer. Prys., Chaps. 
Ix., X11), that, in the Vegetable Kingdom, there are two 
distinct modes by which the propagation of Plants may 
take place ;—the extension of the parent structure into new 
portions, which, being independent of it and of each other, 
can maintain their lives when separated from it ;—and the 
origination of a new being by the concurrent action of two — 
sets of cells set apart for this special function, and desig- 
nated “sperm-cells” and “germ-cells.” The bodies of the 
first class are known as leaf-buds or gemme in the Flowering 
Plants, and sometimes also among Cryptogamia, some of which 
last, as the Marchantia (Vecrr. Puys. § 757), are fur- 
nished with a peculiar means of producing them ; and it | 
appears from recent investigations that the “ spores ” of Ferns, 
