240 



The problem was then attacked from another angle by Dore and Miller (192.?), 

 in connection with the investigations of this Committee. It was undertaken to deter- 

 mine whether or not the wood particles are chemically changed in their passage through 

 the digesti\e tract, by analyzing and comparing the composition of the ejected borings 

 with that of the original wood. Blocks of wood containing numerous teredos were 

 kept in aquaria, where the organisms continued boring and appeared to thrive. From 

 time to time the wood borings ejected from the siphons were remo\ed from the aquaria 

 with a long pipette. In about eight months sufficient material was accumulated by 

 this method to permit of successful analysis. 



The possibility was recognized of changes occurring in the composition of the 

 wood subsequent to ejection, especially as it was not always possible to collect the 

 borings with desirable promptness. In order to test the probability of such changes, 

 some of the borings (series 1, sample 2, below) were allowed to remain on the bottom 

 of the aquarium for about si.K months before being pipetted ofif. 



^f<. ..:--. y-^ ^\ \. r-^ 



1^ 



.. *"*.-;•.. u ' ».'.' \ ,f^ ^ ^ 



^ ^ ''-.- ' . I ■ ■ Jfc* , - 



t;X"y •■< 



Fig. 91. Wood borings ejected by Teredo, x 300. Observe that in many of the particles the cell 

 walls are visible. 



The borings as collected were dried overnight at 100 degrees C. in an electric 

 oven, and the dried mass then crushed to pass a wire sieve having 50 meshes to the 

 linear inch. Samples of the original wood were reduced to sawdust, then ground to 

 pass through the 50-mesh sieve. 



In tables 32 and 33 below are given the results of analysis of wood and borings 

 from two different aquaria. 



The purpose in determining moisture, ash and protein was to enable all the data 

 to be reduced to a comparable basis. Since normal wood contains but small amounts 

 of ash and protein, the amounts found of these constituents may be taken as an 

 approximate measure of the non-woody substances present in the samples. Accord- 



