19-3] Dore-Miller: The Digestion of Wood by Teredo navalis 393 



TABLE 4 

 Data of Table 3 Calculated to Percentages op Original Wood 



On this basis, it appears that (luring its passage through the 

 animal's digestive tract the wood has lost about SO per cent of its 

 cellulose, and from 15 to 56 per cent of its hemicelluloses. including 

 from 11 to 10 per cent of it's furfural yielding constituents such as 

 pentosans, etc. 



The simplest explanation of this disappearance of carbohydrate 

 material is that the cellulose and hemicelluloses of wood are partly 

 digested by the teredo and probably hydrolyzed to simple carbo- 

 hydrates which the animal can use as food. This view is consistent 

 with Harrington's (1921) suggestion that the teredo contains enzymes 

 capable of hydrolyzing cellulose; also with the results of Billard 

 (1914), Bierry (1914), and Bierry and Giaja (1912), who have found 

 cellulose-splitting enzymes in other mollusks. 



The cellulose content and lignin content of the three samples of 

 borings are remarkably uniform (see table 3). This would seem to 

 indicate the composition of the residue which the teredo is incapable 

 of digesting. 



The experimental data rest upon the assumption that the ana- 

 lytical products, cellulose and lignin, are true to name. The results 

 for the wood are based on well established methods (Dore, 1919, 1920) 

 and may be accepted without question. In the case of the ejected 

 matter, which is somewhat contaminated with animal remains, there 

 might be some doubt as to whether the product after solution in 

 72 per cent sulfuric acid is actually lignin and whether the loss in 

 weight which the chlorinated residue underwent really represents 

 cellulose. 



In order to determine the possibility of animal matter remaining 

 undissolved by 72 per cent sulfuric acid and contaminating the 

 lignin, the following experiment was performed: Several teredos 

 were taken from the wood and the caeca dissected out and rejected, in 



