A QRITICISM OF THE CELL-THEORY. 147 
light facts, such as the continuity of cartilage cells, which were 
unsuspected when Hickel wrote. 
I am therefore far from being satisfied that the independent- 
life-unit theory has had such a dominant influence as Mr. 
Sedgwick would have us believe; and I am quite certain that 
the picture which he draws of the teaching given to every 
student of biology is a travesty of the truth. 
Biology includes botany as well as zoology, and if we were 
to allow (which I do not) that zoologists generally have 
become as narrow in their conceptions of the processes of 
development as Mr. Sedgwick says, it is quite certain that 
botanists have not. And as all students of biology are—or if 
they are not, they ought to be—put through a course of 
elementary botany as well as of zoology (in many schools the 
subjects are combined), grave blame must be imputed to those 
teachers who have, in the later stages of their education, 
warped the liberal conceptions which they must have formed 
on the subject of organic growth and development. For I take 
it that, after a study of Mucor, Vaucheria, and the Myxomy- 
cetes, there is no student so dull but he will have imbibed 
ideas respecting cell growth which impel him to ask the 
question which as Mr. Sedgwick says it is so difficult to find 
an answer to—“ What, after all, is a cell?” If, when he asks 
this question, he is told that the cell is an isolated corpuscle 
of protoplasm, the unit of vitality, and that there is “a most 
fundamental distinction” between unicellular and multicellular 
organisms, and so forth, the student may go on his way 
rejoicing, for that he has at last been given a clear and tangible 
statement; but none the less he will have been started on a 
very wrong path. I have not a widespread experience of 
zoological teaching, but I know, at least, that Professor 
Lankester’s pupils are not started on that path. The truth is, 
and, if I am not much mistaken, zoologists and botanists alike 
have long been possessed of it, that there is no fundamental 
but only a formal distinction between unicellular and multi- 
cellular organisms; that the cell is a form concept founded 
on a very wide basis of experience, whereby we can conveniently 
