Juty 5, 1918] 
dicotyls themselves. Among various dicotyls, 
which haye a Lower Cretaceous record and nu- 
merous present representatives, are not only 
the Magnoliacee and Trochodendracex, but 
Berberidacer, Myricacee, Salicacee, Fagacer, 
Moracee (figs), Lauracer, Myrtacee (Huca- 
lyptus). The list might be greatly extended. 
As a clue to the nature of the real early char- 
acters of dicotyls attention may be turned to 
the sassafras, poplars, elms, oaks and mag- 
nolias, all typical in the Comanchian. All 
these must show recognizable archaic char- 
acteristics in the seedlings; and in making 
comparisons with gymnosperms, Araucaria and 
the cycads afford just as critical data as the 
cycadeoids. G. R. Wievanp 
YALE UNIVERSITY 
SPECIAL ARTICLES 
THE REGULATION OF BLOOD VOLUME AFTER 
INFUSIONS OF SOLUTIONS OF VARIOUS 
SALTS. PRELIMINARY NOTE 
In the recent work of Rous and Wilson? it 
was demonstrated that the disastrous effects of 
hemorrhage are not the result of the with- 
drawal of hemoglobin from the circulation. 
They bled an animal until the hemoglobin was 
reduced from 80 per cent. to 20 per cent., i. e., 
three fourths of the original hemoglobin of the 
animal was removed without consequent serious 
effects. A reduction of four fifths, however, 
resulted in a somnolent, torpid condition, fol- 
lowed by death. Under the conditions of 
severe, sudden hemorrhage observed in man, 
the hemoglobin content is never reduced as 
much as these authors report. 
Bayliss? has shown that the factor which 
makes the results of sudden hemorrhage severe 
is the lowered blood pressure consequent to the 
reduction of volume of fluid in the circulatory 
system. Bayliss and Rous and Wilson state 
that saline infusion is almost useless in sus- 
taining blood volume; and Bogert, Mendel and 
Underhill? have shown in what a surprisingly 
1 Rous and Wilson, Jour. American Medical As- 
sociation, 70, 219. 
2 Bayliss, Proc. Royal Society, 89, 380. 
8 Bogert, Underhill and Mendel, Am. Jour. Physi- 
ology, 41, 189. 
SCIENCE 21 
short time infused saline solution leaves the 
circulation. Bayliss reports satisfactory re- 
sults in sustaining blood volume when colloidal 
solutions of approximately the same viscosity 
as blood are used as infusion fluids. He used 
6 per cent. gelatin or 7 per cent. acacia in 
Ringer’s solution. Rous and Wilson have 
used the same solutions with the same satis- 
factory results. They also have used human 
plasma and horse serum. Human plasma has 
given them their best results. They dispute 
Bayliss’s contention that the infusion fluid 
must have the same viscosity as blood. Hur- 
witz* has used Locke solution containing 5 per 
cent. acacia for infusion in human patients 
and reports satisfactory results. 
In the course of some experiments of a some- 
what different nature, the writer has had oc- 
casion to measure the rate of disappearance 
from the circulation of various isotonic solu- 
tions, each containing the same cation but a 
different anion. In view of the timeliness of 
this question of maintenance of blood volume, 
it seemed worth while to offer at this time what 
information was available which had a bear- 
ing on this problem. 
The solutions examined were isotonic with 
rabbit’s blood. The bromide, nitrate, acetate, 
chloride, sulfate and thiocyanate of sodium 
were the salts used. These solutions were in- 
jected into the jugular vein of rabbits which 
had been anesthetized with ether. Blood sam- 
ples were taken from the carotid and the dilu- 
tion of the blood after injection was followed 
by the hemoglobin percentage, using the Hal- 
dane technic. Fifty cubic centimeters per 
kilo body weight, or the approximate blood 
volume, was injected in two minutes. The 
average time for the blood volume to return 
to normal after the injection was less than an 
hour for every salt used except one. This ex- 
ception was the sulfate. When this salt was 
used the blood volume did not return com- 
pletely to normal during the entire experiment. 
The amount of infused fluid which remained 
in the circulation was about 9 per cent. of the 
amount put in. 
4 Hurwitz, Jour. American Medical Association, 
68, 699. 
