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are brought into contact with pi-eviously undisturbed and purely native races. 

 Now, there can bs no doubt that whenever man transplants a vegetable 

 organism, for example, from its native habitat to a foreign soil, he introduces 

 a new force to act upon the indigenous floi-a, a force which experience has 

 shown to be usually so exerted as to lead to the more or less rapid, but in the 

 long run, certain displacement of some portion of that flora. Dr. Hooker, in 

 his admirable paper on "Insular Flora," has shown how effectually this dis- 

 placement has been carried out in small oceanic islands, instancing Madeira, 

 St. Helena, and others, but he did not in that essay apply the theory to such 

 extensive tracts of land as the islands of Kew Zealand. 



[The lecturer then adverted to instances of " displacement," collected 

 from the writings of Hooker, Marsh, and other authors, and proceeded as 

 follows] : — 



The most important point, however, to be noticed in this connection, and 

 one which must be carefully borne in mind in all investigations into the 

 character and extent of the changes to which I am now referring, is, that man 

 has been either intentionally or imintentionally the chief instrument in bringing 

 them about, and that it is only when he co-operates, if I may use the term, 

 with the forces he sets in motion, that they produce any striking or rapid 

 results. 



It must furthur be borne in mind, that such operations, when civilized 

 man engages in the work of colonization, are usually conducted on a very 

 large scale, and this whether the result be intentional and contemplated, or 

 unintentional and imforeseen. And it must still further be observed, that 

 man is naturally aided in this respect by the circumstance that vegetable 

 organisms when naturalized in a new country, either as the result of design or 

 accident, generally exhibit an increased luxui'iance of growth. This is 

 attributable, amongst other things, in the first place to the fact that they have 

 been removed from the influence of those checks to undue increase which 

 have gradually develoj^ed themselves in their natui'al habitat, whether under 

 the operation of the laws governing the " struggle for life," or in consequence 

 of their interfering with the cultivation of the soil ; in the next place to the 

 existence of that attribute to which Mr. Darwin has applied the term " pre- 

 potency ;" and, moreover, to the circumstance that the indigenous vegetation is 

 invaded by a new and unexpected force, against which it had not previously 

 been armed. Until the Ngapuhi tribes had become possessed of firearms, the 

 wars of the New Zealanders were conducted upon a general scale of equality ; 

 bi;t the possession of this force gave to that tribe an increase of power which 

 led to the most frightful results to other tribes. Bands of these heroes mai'ched 

 from one end of this Island to the other, spreading desolation and terror, and 

 ultimately driving the whole native people to the alternative of either adopting 

 a different system of living and of warfare, or of submitting to extinction. The 



