DR. W. H. RANSOM ON THE OVUM OP OSSEOUS PISHES. 
491 
Experiment s was similar to the above, using two free embryos hatched twenty-four 
hours previously. The beating of the heart was regular, 112 per minute, the blood was 
circulating vigorously, no yelk-contractions being seen, and as yet no movement of the 
gill-covers. After three hours the heart’s action was reduced to ninety per minute, the 
movements of the trunk seemed unimpaired. After five hours the heart heat only fifty 
a minute, the blood-corpuscles tended to block up the channels near the auricular aper- 
ture. After seven hours the heart’s action was irregular, and failed at times for forty 
seconds, afterwards beating once a second ; the blood formed a red coagulum near the 
heart ; the trunk did not move. Nine and a half hours after, the heart was beating 
feebly at long intervals, although the trunk was rigid, and recurved as it often is in 
dead fry, and the tissues were opalescent. In eighteen hours all movement had ceased. 
Experiment t was similar to the above, using two free embryos, two days hatched (I 
may say here that the young fry burst the yelk-sac at various stages of development, so 
that the number of days they have been hatched is no safe measure of the stage of deve- 
lopment). At this time they were somewhat further advanced than those in experi- 
ment s, but no action of the gills was seen. After 4f hours they became still as regards 
the trunk, and the heart beat rarely and feebly. 
Experiment v . — As a supplement to these experiments, and as a measure of the value 
of my tests for carbonic acid, I sought for respiratory products in the water in which 
free embryos had been suffocated. 
Sixteen young pike, about one week old (when they are seen to move the gill-covers 
and to vibrate the pectoral fins), were put into 800 grains of distilled water, and the 
beaker, which was full, was covered by a glass plate. They soon showed indications of 
distress, moving the gill-covers much more than their fellows in the aquarium did. 
5f hours after, most of them were motionless at the bottom ; a few were attached to an 
air-bubble which had got in, and these were able to swim. Six and a quarter hours 
after they were all unable to move. The water was filtered and evaporated, the con- 
centrated fluid was neutral, and gave an indistinct cloud with baryta-water. 
Experiment w . — In order to have a physiological test of the extent to which, by pro- 
longed boiling, I had exhausted the oxygen of the distilled water in preparing the 
beakers for the first series of experiments a, b, c, d, I put into one of the same beakers 
twelve young pike, about six or seven days old, passing them through the oil on the 
surface, wrapped in moist bibulous paper unrolled afterwards by a needle. In one 
hour all were quiet but one, although their hearts were acting feebly. In one hour 
and forty-five minutes they were dead. The beaker contained 700 grains of water. 
Experiment x . — Ova passed into pure olive-oil formed no breathing-chamber, and did 
not undergo any change resembling those which occur in water. 
Experiment y . — Ova passed into spirit of turpentine resembled the above, but became 
more opaque. 
These two experiments were made in reference to Nelson’s observations on the ova 
of Ascaris mystax. 
