APPLICATION OF FOREGOING PRINCIPLES. 67 



pseudopodia, which entrap and draw in very minute 

 particles, or absorb nutrient material from the liquid 

 through which they extend themselves, and are con- 

 tinually becoming fused (as it were) into the central 

 body, which is itself continually giving off new pseudo- 

 podia. Now we can scarcely conceive that a crea- 

 ture of such simplicity should possess any distinct 

 consciousness of its needs " (why not ?), " or that its 

 actions shoiild be directed by any intention of its ow r n ; 

 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 geo- 

 metrical 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 tena- 

 cious, 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 'plwspliate of iron secreted from its 

 own substance " (should not this rather be, " which it 

 has contrived in some way or other to manufacture " ?), 



