34 
Here again we note a marked retarding effect on the oxidizing 
power of blood towards alkaline phenolplitlialin on the part of all the 
tissues^ with the possible exception of the suprarenals, and in this 
case the solution had become turbid and hence difficult to read in 
the colorimeter. 
The solutions of blood and of blood containing the several tissues 
were kept on ice for twenty-four hours, at the end of which time 
they were again tested towards alkaline phenolphthalin solution, 
using 2 c. c. of the reagent and 1 c. c. of the several solutions. The 
tests were allowed to stand twenty-four hours at ordinary tempera- 
ture, at the end of which time they were compared in the colorimeter 
with the phenolphthalein standard with the following results: 
[Dec. 18, 1908.] 
Tube. 
Contents 
Colorimeter scale 
readings. 
Test. 
Standard. 
Number (1) 
1 
1 Blood 
5 
1.8 
Number (2) . . 
* Blood and liver 
5 
1.3 
Number (3) 
Blood and marrow 
5 
3.0 
Number (4) 
Blood and pancreas 
5 
3.0 
Number (5) 
Blood and spleen 
5 
1.8 
Number (6).. 
j Blood and muscle. 
5 
.1 
Number (7) 
Blood and lung 
5 
2.0 
Number (8) 
Blood and suprarenals. . . . 
5 
2.0 
Number (9) 
Blood and brain 
5 
.3 
Control 
Water 
Not m( 
iasurable. 
1 
Comparing these results with those obtained with the same solu- 
tion on December 17, 1908, we note a considerable falling off in oxi- 
dizing power in the blood alone (1). Solutions (2), (5), (6), (7), 
and (9) show about the same activity on the two dates, and solu- 
tions (3) and (4) show a considerable increase in activity. It is also 
interesting to note that whereas when first mixed with blood both 
bone marrow and pancreas retard the oxidizing power of blood 
towards alkaline phenolphthalin alone, they seem to accelerate its 
action after twenty-four hours, or possibly they prevent, in some 
way, its decomposition by water. The great retarding effect of mus- 
cle (6) and brain (9) tissues is still seen with solutions of blood and 
these tissues that have stood twenty-four hours. As to the precise 
cause of these remarkable effects, nothing definite can be said at 
present. It is known, however, that most of the fresh animal tis- 
sues possess considerable reducing power, and it is conceivable that 
these have a greater affinity for oxygen than phenolphthalin itself. 
