THE LOWEST FORMS OF LIFE. 
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c encased ’ or ‘ encysted ,’ that is, enclosed in a f cyst ’ (from a 
Greek word, signifying a bag). The cilia disappear, the pedicle 
soon drops off, the contents of the calyx lose their granular 
appearance, and the only signs of organization that remain are 
the ‘ contractile vesicle ’ and the sausage-shaped ‘ nucleus.’ 
“ The last-named begins to subdivide in a similar manner to 
the contents of the cell in Yolvox, and in the course of time 
the whole ‘cyst’ or capsule is filled with a swarm of little 
oval animalcules. 
“ At length, the outer integument can no longer resist the 
pressure of the young brood, and it bursts. The freed 
Yorticellae make their escape and swim off in every direction, 
being furnished at their birth with a little wreath of long cilia. 
Just as in the two preceding cases, they sport about for a time 
in the watery element, and when they have attained a certain 
growth, put forth a footstalk, and ‘ settle down to a quiet life/ 
as you were pleased to designate their ‘'sessile’ stage. 
“ I must now draw your attention to another parallel between 
these lowest forms of animal existence, and the protoph.yta, or 
lowest plants, namely, the ‘settling down’ and becoming 
encysted ■ for, if you recollect, precisely the same process pre- 
ceded the reproductive act in the little ciliated plant forms, and 
not that alone, but the budding process, the ‘gemmation’ of 
Yorticella strongly resembles the same operation in plants, with 
this difference, not to be overlooked, namely, that the Yorticella 
bud derives its nutriment from the fluids in the parent, 
elaborated on the digestion of organized substances, whilst in 
the case of plants the ‘ pabulum’ or food is derived from the 
inorganic constituents of the surrounding elements. 
“More I cannot tell you about Yorticella, for it would 
occupy too much time to describe the various shapes under 
which it presents itself. Sometimes it resembles a shrub, of 
which the central stem only is rigid, and the branches with 
their calyxes contractile : it is then called ‘ Epystilis,’ the 
‘ pillar animalcule ;’ at others it is enclosed in a beautiful cup- 
shaped sheath ; indeed, its varieties or species are manifold, but 
all are alike interesting and beautiful, 
“ Before, however, we bid adieu to these humblest forms of 
life, let me just remark that you are daily in the habit of 
employing, perhaps unconsciously, substances whose nature is 
akin either to the lowest animal or vegetable types. 
“ The common sponge, for example, which you use in your 
bath, is closely allied to Amceba ; for whilst it was growing 
in the sea it formed the support or framework of an extended 
slimy skin similar to Amoeba in its living properties. Some- 
times the inner skeleton, instead of being flexible and horny, is 
silicious ; that is to say, it is composed of innumerable flinty 
