24 REPORT ON BOTANY, MDCCCXLI : 
in the vegetable kingdom. Sclileiden is right, when he says, 
that it is a genuine philosophical principle, to limit the num- 
ber of explanations, provided the reasons existing are sufficient. 
Thus Newton applied this doctrine, by stating, that the move- 
ment of the heavenly bodies did not require any other ex- 
planation than the one given by him. But it would, indeed, 
be unphilosophical to carry this doctrine so far as the author. 
For how can any one admit the impossibility, in experi- 
mental sciences, of explaining an experiment, according to 
an old theory, when one is bold enough to create hypotheses ; 
such, for instance, as has been done here about a deposit in 
spirals. Such a doctrine would be very acceptable to 
M. Dutrochet and the mechanists. 
Herr Sclileiden mentions my former opinions respecting 
the spiral formations in plants, at the commencement of his 
treatise, in the twenty-second volume of the Flora, with a 
view to pronounce them incorrect. He is perfectly right there, 
for I myself have found them to be incorrect. He further 
says : — ‘‘ Link is still far from understanding all the facts 
connected with Botany, and unable to arrange them from a 
correct point of view, as is seen in his newest edition of the 
Philosophia Botanica.” He may likewise not be wrong there, 
for I am far from being so conceited, as to imagine that I 
have perfectly understood nature. 
We have not enumerated, above, a slight controversy which 
took place between Mold and Schleiden, respecting the right 
and left directions of the spiral fibres, because Schleiden re- 
nounces his opinions at the commencement of his preliminary 
answer, and even accuses himself of thoughtlessness. 
Mold says (Flora, vol. xxii. p. 676), No doubt can be 
entertained by any one, who has investigated the development 
of the spiral fibres and the spiral cells, and who has re- 
cognized the decided analogy between these two formations 
and the dotted cells, that the fibre of the spiral vessels is no 
peculiar formation, existing by itself, but that it must be 
considered as the secondary membrane of the vascular sac, 
which has a spiral direction, and is divided into one, or into 
several parallel bands.” I beg to ask. Was the membrane 
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