208 THE STRUGGLE FOR LIFE. 
glands by which the nutrition of the body is effected and 
its waste removed, the blood, the heart and vessels by 
which the circulation of the blood is carried on, and the 
delicate structures of the brain, the organ of thought, are 
one and all ‘ab origine” cells. Even the surface of the 
skin, which requires constant renewal in order that we may 
maintain relations with the external world is covered with 
cells. If the skin be lightly scraped, or a fragment of a 
finger nail be taken and treated with caustic potash, and 
the result examined under the microscope, a single glance 
will show its origin. The secretions of the glands them- 
selves, whether they are destined for further use in the 
body, or. are mere waste to be got rid of, have been at one 
time parts of cells. 
If this were not so, how could a wound of any organ or 
tissue be repaired? If they were formed of a homogeneous 
substance, as of India Rubber for example, repair would be 
impossible. The nuclei of the adjoining cells however, 
retaining their pristine powers of division, nature can and 
does form new cells, and so repairs the continuity by pro- 
cesses similar to the original growth. 
In every living animal there are two kinds of life, viz: 
the life of the animal as a whole, that is, the bodily or 
somatic life, and the separate lives of every individual cell 
of which it is built up. The lives of the separate cells 
are so independent of each other, that an old friend of 
mine, one of the most distinguished Zoologists of the second 
quarter of this century, actually published a classification of 
the Animal Kingdom, in which he grouped the different 
forms of the cells in the body into distinct genera, as inde- 
pendent animals. He was moreover, no mere theorist, but 
an able and acute observer, as you may conclude from the 
fact that he was the first to demonstrate the animal nature 
of the sponge. I do not mention this in order to affirm 
the truth of his theory, but to emphasise the fact that 
