498 Br. W. B. Carpenter, [March 12, 



Physiologist and the Zoologist may draw the most instructive 

 lessons, whilst tlie Geologist finds in it the key to the existence of 

 various stratified deposits of no mean importance both in extent and 

 thickness. 



Though the doctrines of Prof. Ehrenberg as to the complexity 

 of organization possessed by the minutest forms of Animalcules, 

 have now been rejected by the concurrent voice of the most com- 

 petent observers, working with the best instruments, yet the 

 wonders of animalcular life are not in the least diminished by this 

 repudiation of them. Indeed, as great and small are merely relative 

 terms, it may be questioned whether the marvel of a complex 

 structure comprised within the narrowest space we can conceive, is 

 really so great as that of finding those operations of life which we 

 are accustomed to see carried on by an elaborate apparatus, per- 

 formed without any instruments whatever ; — a little particle of 

 apparently homogeneous jelly changing itself into a greater variety 

 of forms than the fabled Proteus, laying hold of its food without 

 members, swallowing it without a mouth, digesting it without a 

 stomach, appropriatiiig its nutritious material without absorbent 

 vessels or a circulating system, moving from place to place without 

 muscles, feeling (if it has any power to do so) without nerves, mul- 

 tiplying itself without eggs, and not only this, but in many instancess 

 forming shelly coverings of a symmetry and completeness not sur- 

 passed by those of any testaceous animals. 



As an example of this type of existence, the Amceha, a common 

 inhabitant of fresh waters, may be first selected. This may be 

 described as a minute mass of " sarcode," presenting scarcely any 

 evidence of organisation, even of the simplest kind ; for although 

 its superficial layer has a somewhat firmer consistency than the 

 semifluid interior, this differentiation does not proceed to the extent 

 of constituting even a body so simple as the " cell " of physiologists, 

 which consists of a definite membrane investing and limiting its 

 contents. Although at some times shapeless and inert, the Amoeba 

 at others is a creature of no inconsiderable activity. Its gelatinous 

 body extends itself into one or more finger-like prolongations ; 

 the interior substance transfers itself into one or other of these, 

 distending it until the entire mass is (as it were) carried into it ; 

 and then, after a short time, another prolongation is put forth, either 

 in the same or in some different direction, and the body being again 

 absorbed into it, the place of the animal is again changed. When 

 the creature, in the course of its progress, meets with a particle 

 capable of affording it nutriment, its gelatinous body spreads itself 

 over or around this, so as to envelope it completely ; and the par- 

 ticle (sometimes animal, sometimes vegetable) thus taken into this 

 extemporised stomach, undergoes a sort of digestion there, the 

 nutrient material being extracted, and any indigestible part 

 making its way to the surface, and being finally (as it were) 

 squeezed out. The Amoeba jnultiplies itself by self-division ; and 



