406 Fatty Acids in Human Blood 
II. 
A review of the literature has shown that in the determination 
of blood fats the extraction followed by saponification of the ex- 
tract was to be preferred to the direct saponification. 'Theformer 
method was introduced by Shimidzu who tried to apply the 
Kumagawa-Suto direct saponification, but found lower results 
than when he had first extracted the blood with alcohol and then 
saponified the extract. Berczeler!* confirmed Shimidzu’s claim 
and recently Rosenthal and Trowbridge! discussing the methods 
of fat determination concluded also that in blood Shimidzu’s 
alcoholic extractions should precede saponification. As a control 
for the blood fat determinations in the present work it was thought 
advisable to run duplicate determinations according to the Gep- 
hart-Csonka" method. To saponify in alcoholic KOH medium 
TABLE III. 
Gm. of Fatty Acids in 100 Cc. of Blood. 
Caseig Be ssce eae pase Bee tee Ane oe os 3 6 9 14 16 18 
CIODE aie tee hati ie 0.300} 0.300) 0.263} 0.282) 0.362) 0.252) 0.307 
Gephart-Csonka method...| 0.325) 0.326) 0.271) 0.318] 0.355) 0.268) 0.428 
in a concentration sufficient to be sure that also the more resist- 
ant esters such as cholesterol esters are split with certainty, only 
5 cc. of blood were used. 
The results in Table III verify the applicability of the Gephart- 
Csonka method for blood in cases where we are interested only 
in the absolute values, with the advantage also of avoiding the 
time-consuming extraction. The above results show further 
that the accuracy was not limited by using such small amounts of 
blood; the higher results were expected, as the extraction is never 
complete, especially in case such large amounts of blood are 
extracted. 
The method as applied to blood is as follows: To 5 cc. of blood meas- 
ured into the author’s saponification and extraction flask 20 cc. of alcohol 
13 Shimidzu, Y., Biochem. Z., 1910, xxviii, 237. 
14 Berczeler, L., Biochem. Z., 1912, xliv, 193. 
15 Rosenthal, H., and Trowbridge, P. F., J. Biol. Chem., 1915, xx, 711. 
