A CRITICISM OF THE CELL-THEORY. 14] 
exist between some cells composing adult tissues, there is an 
antecedent probability that similar connections exist between 
all cells composing all tissues ; and this probability is heightened 
by observations made on the development of Peripatus, by the 
fact that the so-called mesenchyme cells in Avian and Selachian 
embryos are continuous, and not isolated, as was once supposed, 
and by a study of the developing nerves of Elasmobranchs. 
And that it follows from this that the morphological concept 
of a cell, so far from being of primary, is altogether of secon- 
dary importance, and that progress in the knowledge of 
structure is impossible so long as men persistently regard 
cells as the fundamental structural units on which the pheno- 
mena manifested by organised beings depend. The true 
method of enquiry must be a study of the growth, extension, 
vacuolation and specialisation of the living substance—proto- 
plasm. 
It is in this sense that I propose to deal with Mr. Sedgwick’s 
views, and he will pardon me if I have misinterpreted them. 
At any rate, I have done my best to understand them. 
I would wish to show, in the first place, that there is very 
slender ground for the accusations which Mr. Sedgwick levels, 
in an unsparing manner, against his zoological contemporaries. 
He goes so far as to say that their eyes are blinded by theory 
to the most patent facts, and that ‘‘ they are constrained by 
this theory,’—the cell theory,—“ with which their minds are 
saturated, not only to see things which do not exist, but 
actually to figure them.” This is abuse and not argument ; 
if Mr. Sedgwick were to remember the qualifying sentence in 
his writings of 1886, “if they are of general application,” he 
would recognise that there is little occasion for accusing 
zoologists of perversely ignoring the views which he then 
set forth. 
For, in fact, the phenomena to which he draws our attention 
have received their due meed of recognition from the time 
that the cellular structure of tissues was first studied. 
More recent researches have enlarged our knowledge of proto- 
plasmic continuity, but it is still a phenomenon far from- being 
