448 
DE. W. H. EANSOM ON THE OVUM OE OSSEOUS EISHES. 
Observations on the staining of the eggs of the Pike. 
Ripe ova put into water tinged with common alkaline magenta dye, after ninety-six 
hours show a rose colour in the yelk-sac, and a deeper tinge in the granular contents of 
the yelk, in those eggs only, which had a ruptured and collapsed inner sac, with alkaline 
contents. But in those with clear acid food-yelk and unruptured inner sac, there was 
no dye seen beyond the yelk-sac ; while in those with partly diffused formative yelk, and 
partly emptied inner sac, the dye extended only to the diffuse granular matter. Thus 
the inner sac resists the passage of the solution, and the deeper parts of the egg are not 
stained until materially altered. 
Fertile ova, ninety-six hours after impregnation, placed for twenty-four hours in a 
similar solution, continued to develope as in water ; the yelk-sac alone took the dye, the 
embryonic tissues resisted it completely. 
Unimpregnated eggs, put fresh from the parent fish into the same solution, soon 
become stained in the yelk-sac, and if then they he broken, the contents escape free 
from colour. 
A weak ammoniacal solution of carmine acts just like that of magenta, and when tried 
on ovarian ova, I could not succeed in staining the yelk-matter of either kind by cutting 
them in halves, and leaving them in it, although the yelk-sac was easily dyed in the 
same time. The yelk-sac must, I suppose, be looked upon as “ formed material,” yet it 
takes the carmine dye even more quickly and almost, if not quite as deeply, as does the 
formative yelk. The food-yelk, with its portion of inner sac, must, I imagine, be looked 
upon as “ germinal matter ; ” at least it is a protoplasm and contractile, yet it cannot be 
made to take the dye. 
The substance of the primitive yelk after a time takes the dye strongly, and then, 
..compared with the more delicate translucent tissue in which it lies, is a very prominent 
object ; hut it is important not to forget the effect of thickness and physical condition 
in influencing the apparent colour of objects. 
The substance of the formative yelk appears only then to take the stain when it is no 
longer defended by that of the inner sac ; so that it is changed in form and structure 
before it can be dyed, 
I am therefore not disposed to consider staining a satisfactory test of germinal matter, 
for some “formed material” takes the colour quicker and some “germinal matter” is 
destroyed, while other is much changed by the dye fluid ; and some cannot be stained if 
the food-yelk and its cortex be considered one of its varieties. So far as my own observa- 
tions permit me to form an opinion on the constant characters of protoplasm, I should 
at present say that the tendency to vacuolate is the most trustworthy test ; in other 
words, protoplasm is in such unstable equilibrium that its proximate elements easily 
separate by contact with most aqueous solutions. 
e. Remarks on the mode of growth of the yelk-sac and on the germinal vesicle. — The 
former I am, notwithstanding its highly complex structure, disposed to consider as a 
cell-membrane. Whatever may be said as to the mode of its earliest formation, it cannot 
