QUARTERLY CHRONICLE, 163 
animal or part of the tissues of a higher organization, is in 
itself, subjectively, an animated being. The want of self- 
dependence in the cell, which forms a part of the tissues of a 
higher animal, is really not greater than in the single-celled 
infusorium, which lives freely by itself. In fact, each organism 
has its own conditions of life ; and as the tissue-cells can only 
live, for any length of time, in a certain fluid, or in their 
appointed self-wrought habitation, where they dwell as a 
compound organism, so can certain single-celled infusoria 
live persistently only in certain fluids ; they also die if placed 
under conditions to which their organization is not adapted. 
I am not, moreover, at all certain, as before said, of the im- 
possibility of a cell, if once removed from the blood or con- 
nective tissue of a higher animal, and placed in another soil 
(as it were) under favorable auspices, proceeding with its 
life as an independent animal, and becoming the mother of a 
brood of infusoria. 
“From the standing-point which we have now gained, we 
cannot call an organism which consists of more than one cell 
an individual. Such an object is much more like an associa- 
tion of individuals, which live together in a habitation 
wrought by them. ‘The cells have themselves secreted the 
materials for building from their bodies. Association makes 
a division of labour possible. It is no longer necessary for 
each cell to execute for itself every organic function—diges- 
tion, assimilation, &c., in their different stages. One group 
is able much more satisfactorily to execute this, and another 
that office for the whole household ; and thus the particular 
functions are brought to greater perfection, and the per- 
formances of the entire organism become more varied and 
numerous. 
“ The best type of such an association of organic individuals 
is a plant. Here we see different groups of cells execute 
different offices which benefit the whole plant. One set 
extracts material from the ground, another elaborates it in 
various ways ; others again draw material from the air ; others 
are especially fruitful in producing new generations. But we 
do not attain to the higher efforts of physical activity in the 
plant. The reason of this is easily seen. 
“In plants each single cell surrounds itself directly with a 
membrane of the so-called cellulose, the substance which we 
have before us in wood, in cotton, and in paper. The cells 
are by means of this individually shut up; they can, it is 
true, influence one another to a certain degree, in that they 
can transmit material to one another; but they cannot influ- 
ence one another to an unlimited extent; they cannot share 
