80 General Notes. [ January, 
may frequently find recently hatched embryos, around the affixed 
pole of the yolk-sack of which shreds of the ruptured egg-mem- 
brane still adhere ; during the later stages such shreds are not 
usually visible. There is a decidedly heterocercal tail developed 
from a special tail-fold, since there is no absolutely continuous 
median fin-fold developed, as in many other forms. 
Oviposition occurs about the middle of July, in the latitude of 
Wood's Holl. How long it lasts has not been determined, but 
judging from the condition of the roes and milt of the adults at 
that time, it seems very probable that they do not spawn later.— 
John A. Ryder. 
PHYSIOLOGY. 
CONDITIONS WHICH DETERMINE COAGULATION OF THE BLOOD.— 
Herr Holzmann adds something to our knowledge of the con- 
ditions of blood-clotting. His results are summed up as follows: 
1. A body called fibrinogen, belonging to the class of globulins, 
can be obtained from horse’s blood, and solutions of fibrinogen 
neither coagulate spontaneously at ordinary temperatures nor 
upon dilution with water. 2. Defibrinated blood, blood serum, 
watery extract of the albuminous coagulum formed in blood 
serum by the addition of alcohol, or the extract obtained from egg- 
albumin coagulated in the same way, the putrescent fluids ob- 
tained from cooked egg-albumin, and long-continued passage of 
oxygen, all cause typical coagulation of the solution of fibrinogen 
at ordinary temperatures, with the production of fibrin. 3. Fib- 
rin-ferment is not peculiar to the blood, but occurs among the 
decomposition products of albumin. 4. It is probable that fibrin 
is the product of the oxidation of fibrinogen. 5. When a dog is 
rapidly bled to death (one and a half to three hours), the last 
portions of blood drawn clot quicker than the first, though the 
amount of fibrin formed does not markedly vary. 6. Venous 
blood clots more slowly than arterial blood; suffocation delays 
coagulation. Curare, chloralhydrate, chloroform, quinine and 
soda carbonate, also delay the coagulation. 
SPECIAL PHYSIOLOGY OF THE Empryo.2— The last of the four 
separately issued parts of this work having now appeared, it 
becomes possible to speak of it asa whole. It may be said that the 
author has done for the physiology of the embryo what Balfour 
did for the morphology in his Hand-d00k. Some of the researches 
described here are closely connected with those on new-born 
children described in the author’s previous work, Die Seele des 
Kindes, to which he has frequently occasion to make reference. 
His most important general results are that mobility appears long 
before sensibility, and that the sense-organs and the parts of the 
1 This department is edited by Professor HENRY SEWALL, of Ann Arbor, Michigan. 
2 By Professor W. Preyer, Leipzig, 1885. pp. xu. 644. 
