4 J.D. Hooker, Introductory Essay to the Flora of Tasmania. 
estimated by one mind and eye, the errors made under each 
genus will so far counteract one another, that the mean results 
method adopted has absorbed many weeks of labor during the 
last five years, and a much greater degree of accuracy could 
only have been obtained by a disproportionately greater outlay 
of time, whilst it would not have materially affected the general 
results. 
With regard to my own views on the subjects of the varia- 
bility of existing species and the fallacy of supposing we can 
ascertain anything through these alone of their ancestry or of 
originally created types, they are, in so far as they are liable to 
influence my estimate of the value of the facts collected for the 
analysis of the Australian Flora, unaltered from those which 
maintained in the ‘Flora of New Zealand.’ On such theoretical 
questions, however, as the origin and ultimate permanence of 
