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an appliance within the entrance to the rudimentary stomach 
that aids in the selection of suitable nourishment.” 
“ I see the little whirlpool very distinctly, for here the course 
of the current is plainly indicated by the innumerable parti- 
cles of blue colouring matter mixed with the water (plate vii.); 
but, curiously enough, although I fancy I can see a little ball 
of food (of indigo, I should say,) forming near the mouth, 
yet I do not see the particles enter at the aperture.” (Plate viii., 
fig. 3 c.) 
“No; because they chase one another with such rapidity that 
it requires a practised eye to follow them in their course. You 
were correct in saying that you see a ball of food forming near 
the mouth. The food accumulates at the bottom of a little tubular 
or funnel-shaped excavation in the external envelope of the 
body (communicating with the water through the oral aper- 
ture), and when the ball has attained a certain size, it is 
forced, either by its own weight or by the current from 
without, into the interior substance of the calyx, whilst the 
formation of another little pellet at once commences. If you 
were to watch these pellets, you would find that, after they 
have escaped into the cup, they continue to rotate (very 
slowly in Y orticella, but more rapidly in some others of the 
Infusoria,*) until the whole of the nutritive portion is 
extracted, and then the residue is ejected at the rim, and 
carried away by the receding current. Some microscopists 
believe that it is expelled by a second special aperture. This 
observation may be correct, but I will not be responsible for 
its accuracy. So much for the digestion of the food. Now 
a word regarding the means whereby the liquid product of 
digestion is circulated through the body so as to minister to 
its growth. 
“ This fluid, which is analogous to the blood of the higher 
animals, is collected in a contractile cavity resembling those 
which we found in Amoeba and Actinophrys Sol, but in 
the Infusoria it is more perfectly organized. You know in 
what manner our heart operates, driving the blood by its con- 
tractions through arteries to all parts of the body, and receiving 
it back through the veins. Well, in some of the Infusoria the 
contractile vesicle, which is, in fact, the first trace of a heart 
in the animal kingdom,! mimics this operation of the more 
* Plate viii., fig. 4, represents the digestive process in another infusorial 
animalcule, “ Glaucoma scintillans,” in which it may more readily be fol- 
lowed : — 
a Oral aperture, or mouth. 
b Pellet forming at the bottom of the rudimentary throat. 
c Pellets in the body. 
d Digested remains of food escaping from the body, 
t According to some naturalists, it is the rudiment of what is termed the 
‘‘ vascular water system” in the worms. 
