
122 THE NORTHERN MICROSCOPIST. 
themselves by preying on one another) could the ocean waters be purified of 
the carbonic acid which animal respiration and decomposition would be contin- 
ually imparting to them. A Diatomaceous deposit exists in Sweden and Norway, 
under the name of ‘‘ Berg mehl,” or mountain flour ; and in times of scarcity 
the inhabitants mix this with their dough in making bread. Mr. Kirk explained 
the methods for collecting, preserving, and mounting the various Diatoms, and 
illustrated his paper by a large number of beautifully executed drawings of 
typical forms, among the most elaborate of which may be mentioned the 
representations of Arachnoidiscus, Heliopelta, and Isthmia. A discussion 
followed, after which a vote of thanks to Mr. Kirk was proposed by Mr. Selby 
and seconded by the Rev. George Smith ; and the meeting resolved itself into 
a conversazione, Many microscopes being exhibited showing specimens of 
Diatoms. 
DONCASTER MICROSCOPICAL AND GENERAL SCIENTIFIC 
SOCIETY.—A meeting of the above Society was held in the Grammar School 
on Wednesday evening, April 4th, the Rev. G. Smith (vice-president) in the 
chair. An extremely valuable and interesting paper on ‘‘ Cell Life” was read 
by Mr. J. W. Smith, L.R.C.P. Mr. Smith first defined what is meant by a 
cell, and incidently referred to the question of the genesis of cells. Taking the 
amoeba as the most convenient and typical representative of the cell, its actions 
were described—(1) It exhibits movement, (2) receives and digests food, (3) is 
sensitive and volitional, and (4) is reproductive. These qualities are the 
common endowments of all cells wherever found, and may be taken as 
representing all the ordinary manifestations of vitality as seen in the higher 
animals. Whilst these fundamental qualities appertain to every cell, they are 
capable of wide modification and of bringing about many diversified results, 
as is well exemplified in studying the life history of the lowest forms of life, such 
as the yeast plant, protococcus, bacteria, sponges, foraminifera, and the diatoms, 
all of which are essentially single-celled organisms. There is a limitation, how- 
ever, to the performances of the cell organism in its isolated existence. Under 
such circumstances there can be no advance in function. This result is only 
attained when by aggregation, mutual association, and interdependence, a 
division of labour is brought about. The sponges and foraminifera were 
referred to as presenting cell associations in which the separate units are merely 
banded together for obtaining food supplies without establishing any more im- 
portant reciprocal relations with one another. Hence no advance to a higher 
grade of existence. This advance is seen in the higher animals, which are 
simply aggregations of cells, and may be regarded as cell communities in which 
division of labour obtains, certain cells being set apart for the performance of 
certain functions or duties. It was pointed out how in tracing the highest from 
the lowest in the animal kingdom one gradually increasing purpose seems to run, 
viz., aggregation and colonisation of cells with an ever increasing division of 
labour, differentiation of structure and exaltation of function. Illustrative 
examples were given. Mr. Smith remarked that in the infusoria we see the 
greatest perfection attainable by the simple cell as an isolated individual. The 
organisation of the Hydra fusca, which is perhaps the lowest organism in the 
sub-kingdom Ccelenterata, was described as presenting one of the most rudimen- 
tary instances of purposive cell federation. The contractility of the tentacles 
which are used for obtaining food, the performance of digestion by the cells of 
the endoderm, and of reproduction by those of the ectoderm, were mentioned 
as examples of the division of labour which obtains in these little animals. The 
class actinozoa, comprising the corals, sea-anemones, &c., and constitutes a 
more advanced division of the ccelenterata, exhibits further progress in cell 
organisation. In these animals a rudimentary alimentary canal exists. In 
other words, instead of the entire cells of the endoderm performing the office of 
digestion, certain cells are grouped into the formation of a digestive sac for this 

