486 
DR. W. H. RANSOM ON THE OVUM OF OSSEOUS FISHES. 
quickly through the oil on to the eggs, directly after they had been introduced into the 
beaker in the way before described. 
Experiment d . — I used one part ova to ten parts of water, but the attempt to fecun- 
date failed, perhaps from the action of the oil upon the testis. 
Experiments b\ c\ and d', made with varying proportions of ova to water, also failed, 
apparently from a similar cause. The results only served to confirm those obtained from 
the experiments upon unimpregnated eggs, as to the long duration of the rhythmic con- 
tractions. 
I then sought to ascertain the comparative duration of these movements in aerated 
distilled water, with a layer of oil on its surface, employing varying proportions of eggs 
to water ; but as in all these experiments the proportion of eggs which, being defended 
by the superincumbent layers, did not freely imbibe water was large and variable, the 
results obtained lost much of their value. I will mention, however, that the supernatant 
water, after 100 hours, did not precipitate baryta-water more freely than that from 
the experiment a, and had the same very faintly acid reaction. 
These results not being conclusive, partly because of the difficulty of properly watching 
with the higher powers contractions going on in the eggs contained in beakers, partly 
on account of the eggs not being all equally acted on by water, partly in consequence of 
the failure to fecundate through a layer of oil, I obtained a further supply of ripe male 
and female pike, and on April 12th and 13th made a second series of observations, using 
glass cells having a depth of and a cubic capacity of about •05". In these experi- 
ments I sought to ascertain, by varying the proportions of eggs to water, air being 
excluded, whether the duration of the rhythmic contractions of the yelk, or their 
vivacity and the activity of the cleavage, were inversely as the number of eggs. 
Control experiment 3. — For purposes of comparison, unimpregnated ova were passed 
from the female fish into ordinary distilled water in a wide beaker, so that they formed 
only one layer on the bottom. Four hours after, they were contracting freely, and the 
discus proligerus was concentrated, but smooth on its surface. Twelve hours after, it was 
in some lobulated, and in many detached, wholly or in part. Twenty-five hours after, 
they were vigorously contracting and oscillating; in nearly all the discus proligerus was 
detached, and in many of these its substance was fused, so as to run like a stream of lava : 
in a majority the inner sac was ruptured and more or less emptied. Thirty-five hours 
after, in all the discus was detached and diffused, but where the inner sac was not rup- 
tured, or ruptured and only partly emptied, the yelk was actively contracting and rotating. 
Forty-eight hours after, the water, which had not been changed, was faintly milky, of a 
neutral reaction, and did not precipitate baryta-water : filtered and concentrated, it was 
alkaline, was precipitated by baryta-water, and the flocculent precipitate was only in part 
dissolved by hydrochloric acid : dried and strongly heated, it charred, and gave off fumes 
having the smell of burning hair, and it left an alkaline ash which did not effervesce with 
dilute hydrochloric acid. In this case there must have been a transudation of some 
organic substance, which probably was limited to the eggs with ruptured inner sacs. 
