PROTOZOA. 
19 
the tenacity with which the smaller rotifer retained its 
hold ; for although one might think that it was being 
almost jerked to pieces, after each bout of jerking it was 
seen to be still attached. This trial of strength, which 
must have involved an immense expenditure of energy in 
proportion to the size of the animals, lasted for several 
minutes, till eventually the small rotifer wns thrown 
violently away. It then returned to the conflict, but did 
not succeed a second time in establishing its hold. The 
entire scene was as like intelligent action on the part of 
both animals as could well be imagined, so that if we were 
to depend upon appearances alone, this one observation 
would be sufficient to induce me to attribute conscious 
determination to these microscopical organisms. 
But, without denying that conscious determination may 
here be present, or involving ourselves in the impossible 
task of proving such a negative, we may properly affirm 
that until an animalcule shows itself to be teachable by in- 
dividual experience, we have no sufficient evidence derived 
or derivable from any number of such apparently intelli- 
gent movements, that conscious determination is present. 
Therefore, I need not wait to quote the observations of 
the sundry microscopists who detail facts more or less 
similar to the above, with expressions of their belief that 
microscopical organisms display a certain degree of instinct 
or intelligence as distinguished from mechanical, or wholly 
non-mental adjustment. But there are some observations 
relating to the lowest of all animals, and made by a com- 
petent person, which are so remarkable that I shall have to 
quote them in full. These observations are recorded by 
Mr. H. J. Carter, F.R.S., in the c Annals of Natural 
History , 5 and in his opinion prove that the beginnings of 
instinct are to be found so low down in the scale as the 
Rhizopoda. He says 6 Even jEthalium will confine 
itself to the water of the wntch-glass in which it may be 
placed when away from sawdust and chips of wood among 
which it has been living ; but if the watch-glass be placed 
upon the sawdust, it will very soon make its way over the 
side of the watch-glass and get to it . 5 
This is certainly a remarkable observation : for it seems 
