1915] ; HARVEY—ETHYLENE 201 
from (d)—[(6)—(c)] should give an approximate figure for the 
cellulose present. 
2. Carbohydrates 
Reducing sugars, before and after hydrolysis, were determined 
for the alcohol-ether soluble fraction. The methods employed 
were those of Munson and WALKER (26, pp. 241-251). The 
reduced copper was determined by the volumetric permanganate 
method described in the above-named bulletin (p. 52). Similarly, 
the reducing sugars were determined for the insoluble fraction after 
2.5 hours of hydrolysis with 3.5 per cent HCl. 
3. Nitrogenous substances 
Total nitrogen was determined by the KyELDAHL method and 
the amino acids and amids by both the formol titration (as described 
by JESSEN-HANSEN, 14, and VAN SLYKE’s methods, 34). While 
employing the latter method, estimations were made of ammonia 
and alpha-NH, groups both before and after a 24-hour hydrolysis 
with 20 per cent HCl at 98-99° C. (see 35). 
4. Fats 
Only the dry weight of the ether extract and the free fatty acid 
value were estimated. Separate samples were used for fat deter- 
minations. The tissue was collected and preserved as previously 
described, but instead of the alcohol extraction being used as before, 
the tissue was spread out to dry in a current of air, absolute alcohol 
being added from time to time to hasten the drying process. The 
dried tissue was then extracted for 12 hours with absolute ether. 
Also, the preserving liquid was evaporated, the residue dried in 
vacuo, and taken up with absolute ether. The ether extracts were 
combined, dried in vacuo, and the weight determined. Free fatty 
acids of this residue were estimated by titration in the usual manner. 
5. Results 
The following statements are made in explanation of the tables 
of results. Whenever percentages are given, the figures are always 
in terms of the total dry weight of the samples. Also, the numbers 
of the samples are given in order to facilitate proper comparison 
