THE WEB OF LIFE 65 



Colorado Beetle in Ireland. " Ignorance of nature," 

 Mr. A. H. S. Lucas says, " is costly. By disturbing 

 the balance of nature, man has introduced foes 

 into his own household." Speaking of Australia, 

 he says : " How much is needed for the eradication 

 of Bathurst Burr, Prickly Pear, Water-hyacinth, 

 Bramble and Sweetbriar, Codlin Moth, Waxy 

 Scale, Pear Slug, and Red Spider, owing to care- 

 lessness or lack of knowledge in early days ? " ' 



An obvious moral is that we should be careful 

 in our introductions of new organisms — ^man 

 included — into new surrotmdings. The primary 

 consequences may be predictable, but the secondary 

 and the tertiary consequences — ^who is sufficient 

 for these things ? We have records of the un- 

 conscious introduction of rats into Jamaica, where 

 they became a pest. To destroy them mongooses 

 were imported, and the rats were soon checked. 

 But the mongooses, having finished the rats, began 

 to eat up the poultry and young birds of various 

 kinds. As this went on the injurious iasects and 

 ticks, that the birds used to eat, began to gain 

 the ascendant. A recent report — which requires 

 confirmation — says that the increase of ticks is 

 making Hfe a burden to the mongooses. Thus a 

 balance will be again arrived at. There is no 

 doubt of that, but how much is often unnecessarily 

 lost by the way ! 



^ " Presidential Address, Proc. Linueaa Society N.S. Wales " 

 (1908), voL xxxiii. pp. 1-38. 



