58 



(See p. 292). The intensity of attack in higher temperatures may be accounted for 

 in part by the facts that propagation and activity of the borers is increased in the 

 warmer waters, and that such water tends to leach out chemical preservatives more 

 quickly than does the colder, hence destroys the effectiveness of preservatives sooner. 



TESTS AND OBSKRVATION'S OF INFKSTATION 



If information on actual conditions of infestation in any locality is lacking, 

 tests should be conducted to determine the condition. Thev must be made with care, 



22. (1) Creosoted Douglas fir pile from Pier 7, San Francisco, destroyed near the mud line by 

 Baukia and Limnoria. Note deviating direction of Bankia burrows. 

 (2) The same, Bankia burrows, only, within creosoted zone. 



bearing in mind all the influences to be considered, as pre\iously discussed; and it 

 must be understood that the results thus olitained will show only conditions prevailing 



