38 Composition of Hggs. 
tude of oscillation is on the side of India. ‘The northern excur- 
sion is much greater in the northern hemisphere than is the 
southern excursion on the side of the southern hemisphere. The 
European atmospheric relations, especially in summer, are there- 
fore essentially of a secondary nature; and we must regard: the 
little alteration in the atmospheric pressure in the course of the 
year in Europe as a secondary result, of which the explanation 
would not have been possible without the observations from Asia 
and Australia. 
Berlin, January 5, 1853. 
Arr. VIL.—On the waar of Eggs in the series Fd Ani- 
mals—Partl. By A . Vauencrennes and Fremy 
Anaromists who undertake new researches on the eggs of ani- 
mals, are obliged, while extending their a to the dif- 
ferent species of the animal series, to recur o the eriods, now 
distant, of the publications of Prevost and TAak and of Charles 
Ernest Baér. The discovery of the former confirmed the opinions 
of William Cruikshanks, founded on observations and exact ex- 
periments; and that of M. Baér, who succeeded in seeing the 
first rudiments of the ovule, even under the stroma of the ovary 
of mammals, made one step more in Ovology. 
That distinguished anatomist, while aiming to follow the evo- 
lution of the feetus, not only in the eggs of animals of that class, 
but in’ the different members of the animal kingdom, did not 
attempt to ascertain the nature of the liquids, more or less dense, 
of the egg, nor of those bodies held in suspension or dissolved 
in these liquids. 
same direction was pursued by those anatomists who 
have treated this subject before and after M. Baér. We should 
digress too much if we were to give a bisa of their success- 
ful labors. We believe it useful however to recall the course 
followed by the clever anatomist of Kenigsberg and by his 
successors, in order to explain how it is that no one has yet 
investigated what the microscope has discovered in the vitellus 
(the yolk) of different eggs. It seems to us beyond a doubt that 
ér saw the granular yolks of different kinds of ray fish and 
sharks, without ‘studying them in detail. He did not try to 
oneemer their real nature by the aid of chemical analysis. He 
ited himself in fact, to saying that the yellow consists of a 
tte liquid, of colorless grains of albumen, and of fat almost 
always divided into minute drops, This yellow is surrounded 
* white but M. Baér did not try whether it would coagulate 
: parca ee TINS 2 by Dr, J. Ro- 
Dall 
RE thems Ri ne i SaaS le te, la 
TO ate | 
