DR. W. H. RANSOM ON THE OVUM OE OSSEOUS FISHES. 
489 
they were cleft into the mulberry stage, but somewhat coarser than their control ova : 
the contractions were vivid. After twenty-three hours the germinal mass was in the finer 
mulberry stage. After twenty-nine hours no further progress was made in the cleavage, 
but the contractions continued. 
Concurrently with these suffocative experiments, as they may be termed, I tried to 
ascertain whether any, and what respiratory products could be detected in the sur- 
rounding medium, and I considered separately impregnated and unimpregnated ova, 
with the view of comparing the rhythmic contraction with the movements of cleavage. 
Experiment 7c . — I placed unimpregnated ova, fresh from the fish, in a tube with two 
parts of distilled water, agitating to ensure that all were well exposed to the water. 
The contractions continued for forty-eight hours, although latterly with less vigour than 
in the control eggs. The water, which was then clear, and neutral when filtered, gave 
no precipitate with baryta-water, was not coagulated by boiling or by alcohol, but was 
by protonitrate of mercury. 
Experiment l was the same as the above, with one part of eggs to five of distilled 
water ; the results after forty-eight hours were the same. 
Experiment 7c ' was similar to the last, but made with impregnated eggs in the ratio of 
one to four of water, the semen being washed away as quick as possible. Development 
was arrested before the germinal mass had extended over one-third of the yelk. After 
fifty hours all were still. The water, which was not quite bright even when filtered, 
was neutral or faintly acid in its reaction, was not precipitated by baryta-water, was 
coagulated by heat and nitric acid and by alcohol, more freely precipitated by proto- 
nitrate of mercury. Probably in this experiment an egg may have been ruptured while 
introducing it into the tube. 
Experiment l' was the same as the above, with one part of ova to eight of water. 
Eifty hours after, all were still. The water when filtered was clear, the reactions were 
the same as those in experiment 7c', except that it was not coagulated by heat and nitric 
acid, or by alcohol ; so that the albumen must have been accidental in 7(7. 
Experiment m . — As the number of ova used in experiment 7c was small, I repeated 
it in a flask, in which about half an ounce of spawn was put into two ounces of distilled 
water. Agitation was kept up for a time to ensure that all the eggs were duly exposed 
to the water. After twenty-eight hours they were contracting freely. No ruptured 
eggs were seen among them. The water was bright ; it was filtered and evaporated ; the 
concentrated liquid was faintly alkaline, the dry residue resembled dry serum, contained 
an organic colloid, not albumen, with alkaline phosphates, chlorides and sulphates; but 
no evidence of carbonic acid was found. The organic matter was not further examined. 
Experiment m' was the same as the above with fertilized ova. After thirty hours, 
while all the movements were active and cleavage was progressing, there being but few 
opaque ova in the flask, the water was filtered quite bright, and evaporated. The resi- 
due had the same reactions as had that of experiment m. 
In order to permit a comparison of the consumption of oxygen in protoplasmic move- 
3 u 2 
