A CRITICISM OF THE CELL-THEORY. 167 
Continuous cells, whose protoplasm is fused but whose 
nuclei are separate, e.g. Myxomycetes, Celoblaste, 
Opalina. 
Conjunct cells, those which having a protoplasmic body 
of definite outline are united inter se by fine bonds of proto- 
plasm, e.g. vegetable tissue cells, epithelial cells of many 
animals; mesenchyme cells, &c. 
Experience shows us that independent cells may, in process 
of growth, give rise to coherent cells, continuous cells, con- 
junct cells, or to all three together, and that coherent, con- 
tinuous, or conjunct cells may, and in fact do, give rise to 
independent cells. As thus stated, can there be a better 
illustration of von Sachs’s principle that cell-formation is an 
accompaniment of growth? 
It will be observed that, in adhering to the present termi- 
nology, I am obliged to classify organisms usually (though not 
always) called unicellular as multicellular. I have tried to 
escape from this necessity, but the limitations of language 
compel me to it. I should be grateful for a better and more 
logical definition. 
The view of Mr. Sedgwick—if I do not misrepresent him— 
is this, that there are no coherent cells; that all which I have 
classified as continuous and conjunct cells are not cells, but 
tracts of protoplasm; that the only cell, sensu stricto, is 
the independent cell, and that morphologically and physio- 
logically it is of no consequence. 
I have already shown that there are cells which we must 
regard as coherent. I cannot, for reasons which I will explain 
directly, consider the independent cell of no consequence, and 
the difference between us as to conjunct cells is simply this: 
Are they to be regarded as one or many? I can, perhaps, best 
express this difference by an illustration. 
Is a house to be regarded as one room or composed of 
separate rooms? A room isa certain portion of space enclosed 
by walls, ceiling, and floor; but it is also in connection, by 
means of the door, with other similar rooms. Is it, then, not 
a separate room, but part of a larger room? Or if I shut the 
