NATURE-RESERVES 21 



or small. Once man is present in the neighbourhood, 

 even at a long distance, he upsets the " balance of 

 Nature." The naturalist's small " nature-reserve " may 

 be ravaged by predatory animals driven from the outly- 

 ing region occupied by man, or again, the absence from 

 the " reserve " of predatory animals which act as natural 

 checks on the increase of other animals, may lead to 

 excessive and unhealthy multiplication of the latter. 

 Man must " weed " and artificially manage his " reserve " 

 after all ! Man brings also into the neighbourhood of 

 reserves, great and small, disease germs in his domestic- 

 ated animals, which are carried by insects into the 

 cherished " reserve," and there cause destruction. Con- 

 versely, the animals maintained in a reserve carry in 

 their blood microscopic parasites to the poisons of 

 which they have become immune by natural selection 

 in the course of ages. They act as " reservoirs " of 

 such microscopic germs. These germs carried by flies 

 or other insects to the carefully reared cattle imported 

 by civilized man from other regions of the world into the 

 neighbourhood of such " reserves," cause deadly disease 

 (such as the tsetse-fly diseases or trypanosome diseases) 

 to those imported cattle, as also to man himself. Whilst, 

 then, we may do something to retain small tracts of our 

 own country in the modified state which it attained after 

 the earlier inhabitants had destroyed lion, bear, wolf, and 

 other noxious animals, as well as great herbivora, such as 

 giant deer, red deer, aurochs (or great bull), and bison — 

 yet in reality a true " Nature-reserve " is not compatible 

 with the occupation of the land, within some hundreds of 

 miles of it, by civilized, or even semi-civilized, man. 



Nothing but the isolation given by a wide sea or high 

 mountain ranges will preserve a primeval fauna and flora 

 ' — the indigenous man-free living denizens of the isolated 



