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University of California Publications in Zoology [Vol. 22 



order to eliminate the wood particles they contained. The flesh, thus 

 freed from woody matter, was then dried and pulverized. The residue 

 was digested overnight in cold 72 per cent sulfuric acid and then 

 diluted in the same manner as in carrying out the lignin determina- 

 tion. Solution of the material was practically complete, showing that 

 the presence of animal remains in the residue does not interfere with 

 the lignin determination. 



In the case of the cellulose, considerable difficulty was experienced 

 in filtering and washing the material after the second chlorination. 

 This appeared to be due to the presence of colloidal material in the 

 mass. On dissolving out the cellulose from this residue by 72 per 

 cent sulfuric acid, considerable amounts of insoluble substance were 

 obtained, as shown by table 5. 



TABLE 5 



Cellulose Content op "Wood and Borings 



(Expressed in grams obtained from 1 gram of original material) 



It is not believed that the insoluble residue contained a great deal 

 of animal matter, as such material appears to be largely soluble in 

 72 per cent acid under the conditions employed. The residue is con- 

 sidered as consisting largely of lignin which escaped chlorination, due 

 partly to the protective action of the colloidal mass and partly to the 

 fact that the chlorination was not continued as long as usual on 

 account of mechanical difficulties. 



It is to be noted that the second sample of borings in Series I 

 contains considerably more protein than the first sample of borings 

 of the same series (see table 1). Nevertheless, it gave a much smaller 

 yield of insoluble material in the cellulose determination, and the 

 figures for cellulose and lignin were very similar to those from the 

 other samples. This would tend to indicate that the methods used 

 for cellulose and lignin are not affected by the amount of animal 

 debris present in the sample. 



It can be shown that, even if the analytical methods are seriously 

 defective, the greatest possible allowance for contamination of 

 products does not invalidate the general conclusion that the borings 



