204 THE HISTORY OF CREATION. 
of attraction and repulsion in the particles or molecules—in 
fact, to the motional phenomena of matter. 
Now, before we turn our attention to the second function. 
the phenomenon of Adaptation or Mutability, which counter- 
acts the Transmission by Inheritance, it seems appropriate 
first to cast one more glance at the various manifestations of 
Heredity, which we may perhaps even now denominate the 
“ laws of transmission by inheritance.” Unfortunately, up 
to the present time very little has been done for this most 
important subject, either in zoology or in botany, and almost 
all we know of the different laws of inheritance is confined 
to the experiences of gardeners and farmers. It is not 
therefore to be wondered at, that on the whole these exceed- 
ingly interesting and important phenomena have not been 
investigated with desirable scientific accuracy, or reduced 
to the form of scientific laws. Accordingly, what I shall 
relate of the different laws of transmission are only some 
preliminary fragments taken out of the infinitely rich store 
which lies open to our inquiry. 
We may first divide all the different phenomena of inherit- 
ance into two groups, which we may distinguish as the 
transmission of inherited characters, and the transmission of 
acquired characters ; and we may call the former the con- 
servative transmission, and the latter the progressive trans- 
mission by inheritance. This distinction depends upon the 
exceedingly important fact that the individuals of every 
species of animals and plants can transmit to their de- 
scendants, not only those qualities which they themselves 
have inherited from their ancestors, but also the peculiar, 
individual qualities which they have acquired during their 
own life. The latter are transmitted by progressive, the 
