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DR, W. II. RANSOM ON THE OVUM OF OSSEOUS FISHES. 
cept the oil-drops. The surface of the drop within the inner sac I had some reason to 
think a little less dense than the centre, as it ran rather more freely, but all parts 
flowed from a rupture like a very thick syrup. 
The oil is collected into a group of large and small drops and granules, which moves 
freely through the fluid food-yelk, hut not through its centre, to get to the uppermost 
segment when the egg is rolled; in so doing the drops often separate to unite again. 
Sometimes, especially in impregnated ova, they adhere to the germinal mass, and then 
cause it always to float uppermost. 
The food-yelk is acid in reaction to blue litmus, to an extent which more than suffices 
to neutralize the alkalinity of the viscid layer, but its taste is astringent rather than acid. 
It is coagulated firmly by boiling, by nitric acid, or by spirit of wine. Water causes a 
fine molecular precipitate in it, soluble in alkaline chlorides and acetates. Dilute 
acetic acid precipitates freely very fine dark molecules in rapid vibratory movement, 
after the action of the chlorides, or previously, and then dilute nitric acid causes a still 
further molecular deposit of a darker aspect. 
I tested for cellulose in the different parts of the egg without finding any. 
2. The ovarian ovum . — The development of ova in ovario I have only attempted to 
trace in its later stages, i. e. after the first germs of the egg in a distinctly recognizable 
form have been laid. This has been done, mainly, with a view of throwing light upon 
the mode of growth of the parts of the ovum, and upon the ultimate fate of the germinal 
vesicle and its contents. 
a. The ovaries appear completely formed, and containing their characteristic elements 
in very young fry, certainly in those not more than a month old and about long. 
They are, however, better studied in the adult, in which they exist as complex folds of 
vascular connective tissue, not separable from the peritoneum, attached on either side 
of the bodies of the vertebrae, and projecting as leaflets, in which lie the ova contained 
in ovisacs which are lined with epithelial cells, but have no demonstrable basement 
membrane. There is no connexion, beyond that of simple contact, between the outer 
surface of the yelk-sac and the ovisac ; certainly no peduncle. As the position of the 
micropyle can be easily and certainly determined in early ovarian ova by the buttons 
which surround it, the absence of such attachment connected with it is not difficult to 
prove, by watching eggs escape from the ovisacs under graduated pressure. 
The ovisacs are supplied with blood-vessels running in one, two, or more directions, so 
that they are not pedunculated. Younger and more advanced eggs are met with 
together in all parts of the ovary without any definite arrangement. 
The ovaries are enclosed in a sac, which is attached to their bases on either side, and 
anteriorly, but continuous with the sexual aperture behind the vent, and must be looked 
upon as the oviduct. Into its cavity the ova escape when ripe, and remain there for a short 
time before they are deposited ; its walls are muscular, and its inner surface secretes a 
viscid substance which defends the eggs when deposited from the too rapid action of water, 
and which serves as a suitable medium for the spermatozooids to move in. 
