1877.] On the Study of Biology. 213 
into which the microscope will enable them to break him up. 
They consider the performance of his various functions and ac- 
tivities, and they look at the manner in which he occurs on the 
surface of the world. Then they turn to other animals, and, tak- 
ing the first handy domestic animal, — say a dog, — they profess 
to be able to demonstrate that the analysis of the dog leads them 
in gross to precisely the same results as the analysis of the man ; 
that they find almost identically the same bones, having the same 
relations; that they can name the muscles of the dog by the 
names of the muscles of the man, and the nerves of the dog by 
those of the nerves of the man, and that such structures and or- 
gans of sense as we find in the man, such also we find in the dog; 
they analyze the brain and spinal cord, and find the nomenclat- 
ure which does for the one answer for the other. They carry 
their microscopic inquiries in the case of the dog as far as they 
can, and they find that his body is resolvable into the same ele- 
ments as those of the man. Moreover, they trace back the dog’s 
and the man’s development, and they find that at a certain stage 
of their existence the two creatures are not distinguishable the 
one from the other ; they find that the dog and his kind have a 
certain distribution over the surface of the world comparable in 
its way to the distribution of the human species. What is true 
of the dog they tell us is true of all the higher animals ; and they 
find that for the whole of these creatures they can lay down a 
common plan, and regard the man and the dog, the horse and 
the ox, as minor modifications of one great fundamental unity. 
Moreover, the investigations of the last three quarters of a cent- 
ury have proved, they tell us, that similar inquiries carried out 
through all the different kinds of animals which are met with in 
nature will lead us, not in one straight series, but by many roads, 
step by step, gradation by gradation, from man at the summit to 
Specks of animated jelly at the bottom of the series; so that the 
idea of Leibnitz and of Bonnet, that animals form a great scale 
of being in which there is a series of gradations from the most 
complicated form to the lowest and simplest, —that idea, though 
hot exactly in the form in which it was propounded by those phi- 
losophers, turns out to be substantially correct. More than this, 
When biologists pursue their investigations into the vegetable 
world, they find that they can in the same way follow out the 
Structure of the plant from the most gigantic and complicated 
trees through a similar series of gradations until they arrive at 
Similar specks of animated jelly, which they are puzzled to dis- 
tinguish from those which they reached by the animal road. 
