138 GILBERT C. BOURNE. 
better and more distinct principles are put in their place, the 
course of speculation may be expected to be very erratic 
indeed. It is not without serious misgivings as to my own 
competence that I, in default of a better champion, take up 
one of these challenges, and I propose to criticise Mr. Sedg- 
wick’s recent article on the inadequacy of the cellular theory 
of development, leaving for a future occasion the consideration 
of his earlier article on von Baer’s law. 
It is to be regretted that Mr. Sedgwick should, in putting 
forward a view affecting one of the fundamental propositions 
of biology, have chosen to adopt a controversial method, which 
cannot but have the effect of weakening his case. And it is 
still more a pity that he should be so unsparing in abuse of 
his imaginary opponents, whilst he himself commits the very 
fault. for which he so much blames them. For he lays, in the 
front of his indictment, a charge of vagueness and unsub- 
stantiality against the supporters of the cellular theory. 
‘We are dealing,” he says, “ with a kind of phantom which 
takes different forms in different men’s eyes. There is a want 
of precision about the cell-phantom, as there is also about the 
layer-phantom, which makes it very difficult to lay either of 
them. Neither of these theories can be stated in a manner 
satisfactory to every one. The result is that it is not easy to 
bring either of them to book.” 
I shall show, later on, that this charge of vagueness is not 
altogether justified ; what I am at present concerned with is 
to show that Mr. Sedgwick is as much open to the charge of 
vagueness as the rest of the zoological world which he ceasti- 
gates. 
Read his article through as carefully as one may, one 
cannot find any definite or precise statement of his own stand- 
point, saving that he quotes passages from one of his earlier 
works. The critic, therefore, must be content to infer 
from the tenor of the whole article, and from particular 
passages in it, as well as from his previous writings, what 
Mr. Sedgwick does or does not believe with regard to the cell- 
theory, and if he is misinterpreted, it is his own fault. 
