“The simplest type of an animal consists of a minute mass of ‘protoplasm,’ or living jelly, which is not yet _differentiated_ into ‘organs;’ every part having the same endowments, and taking an equal share in every action which the creature performs. One of these ‘jelly specks,’ the amœba, moves itself about by changing the form of its body, extemporising a foot (or pseudopodium), first in one direction, and then in another; and then, when it has met with a nutritive particle, extemporises a stomach for its reception, by wrapping its soft body around it. Another, instead of going about in search of food, remains in one place, but projects its protoplasmic substance into long pseudopodia, which entrap and draw in very minute particles, or absorb nutrient material from the liquid through which they extend themselves, and are continually becoming fused (as it were) into the central body, which is itself continually giving off new pseudopodia. Now we can scarcely conceive that a creature of such simplicity should possess any distinct _consciousness_ of its needs” (why not?), “or that its actions should be directed by any _intention_ of its own; and yet the writer has lately found results of the most singular elaborateness to be wrought out by the instrumentality of these minute jelly specks, which build up tests or casings of the most regular geometrical symmetry of form, and of the most artificial construction.” On this Dr. Carpenter remarks:—“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 from its own substance” (should not this rather be, “which it has contrived in some way or other to manufacture”?) and thus constructs a flask-shaped ‘test,’ having a short neck and a large single 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 them up together—apparently with no cement at all, by the mere laying of the spicules—into perfect white spheres, like homœopathic globules, each having a single-fissured orifice. And another, which makes a straight,