184 Chittenden and Lambert— Post-mortem Formation 
remove any traces of suspended matter which might have passed the 
cotton. Of these fluids, 200 ¢. c. of each were used for the deter- 
mination of glycogen and sugar, and 200 ¢. c. also, for the determi- 
nation of total carbohydrates. 
Determination of glycogen and sugar.—The 200 ¢. ¢. of fluid for 
the determination of glycogen and sugar were evaporated to a small 
bulk and then, when cool, precipitated by a large volume of alcohol. 
After standing 24 hours the clear supernatant fluid was filtered from 
the precipitated glycogen and peptones. The alcoholic filtrate and 
washings, containing the sugar, were then evaporated, the residue 
dissolved in water and made up to 100 ¢.c., in an aliquot portion 
of which the sugar was determined gravimetrically, by Allihn’s* 
improved method. 
The precipitate of glycogen, with its frequent admixture. of pep- 
tone, was dissolved in water, the solution made up to 200 c.c. and 
then sufficient 10 per cent. hydrochloric acid added to make the 
solution contain 2 per cent. HCl. The mixture was then heated in a 
closed flask at 100° C. for 17 hours in order to convert the glycogen 
into dextrose, after which the solution was neutralized, concentrated 
somewhat, again made up to 200 ¢. c. and in an aliquot portion of 
this fluid, dextrose was determined by Allihn’s method, from which 
was calculated the amount and percentage of glycogen. Delpratt 
states that in attempting to determine glycogen by Briicke’s method 
he found the results considerably higher than when, the isolated gly- 
cogen was converted into sugar by boiling with acid and the glyco- 
gen calculated from the data obtained. In our own experiments, the 
frequent presence of peptone prevented entirely the use of Briicke’s 
method. 12 hours heating at 100° C., however, with 2 per cent. 
hydrochloric acid was found in our case insufficient to completely 
convert the glycogen into dextrose, while 17 hours was found amply 
sufficient for complete conversion and at the same time allowed no 
decomposition of the sugar formed. This is well illustrated by the 
following experiments : 
A. 0°7665 gram pure, dried glycogen dissolved in 100 c« «¢ of 
water, was heated at 100° C. for 12 hours with sufficient hydrochloric 
acid to make the entire fluid contain exactly 2 per cent. The solution 
was neutralized, care being taken that the reaction did not become 
alkaline, then concentrated and finally made up to 50 ¢. ¢. 
14 c.c. gave 0°4215 gram Cu=0°2251 gram dextrose=0°2025 gram glycogen. 
14 ‘ “ 0°4233)0 “* S Cu==0°2263 = 0°2036 . 
* Zeitschrift fir analytische Chemie, xxii, p. 448. 
+ Jahresbericht fiir Thierchemie, 1881, p. 322, 
a 
