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extreme illustration to test the truth of this principle. 
The simplest type of an animal is an amceba. It consists 
of a minute mass of protoplasm or living jelly, every part 
of which has the same endowments and takes an equal 
share in every action which the creature performs.* The 
amoeba is sensible to impressions ; moves more or less 
quickly and voluntarily ; selects the food which it likes, 
and assimilates organic matter; it breathes in as much 
as it expires carbonic acid formed in the process.j- Of 
one of these “ jelly-specks,” the gromia, Dr. Carpenter 
says:— 
“ Suppose a human mason to be put down by the side of a pile of 
stones of various shapes and sizes, and to be told to build a dome of 
these, smooth on both surfaces, without using more than the least 
possible quantity of a very tenacious but very costly cement in 
holding the stones together. If he accomplished this well, he would 
receive credit for great intelligence and skill. Yet this is exactly 
what these little ‘jelly-specks’ do on a most minute scale; the ‘tests’ 
they construct, when highly magnified, bearing comparison with the 
most skilful masonry of man. From the same sandy bottom one 
species picks up the coarser quartz-grains, cements them together 
with phosphate of iron secreted rom its own substance, and thus 
constructs a flask-shaped ‘test’ having a short neck and a single 
large orifice. Another picks up the finest grains and puts them 
together with the same cement into perfectly spherical ‘ tests ’ of the 
most extraordinary finish, perforated with numerous small pores, 
disposed at pretty regular intervals. Another selects the minutest 
sand-grains and the terminal portions of sponge-spicules, and works 
these up together—apparently with no cement at all ; by the mere 
‘laying’ of the spicules—into perfect white spheres, like homoeopathic 
globules, each having a single fissured orifice. And another which 
makes a straight, many-chambered test that resembles in form the 
chambered shell of an orthoceratite, the conical mouth of each 
chamber projecting into the cavity of the next, while forming the 
walls of its chambers of ordinary sand-grains rather loosely held 
together, shapes the conical mouths of the successive chambers by 
firmly cementing together grains of ferrugmous quartz, which it must 
have picked out from the general mass.”—{Principles of Mental 
Physiology, pp. 42-43.) 
Carpenter, 
t Semper.