Development of the Ovum. By W. II. Dallinger & J. Drysdale. 95 
destiny of the nucleus and nucleolus ; and quite repudiates the 
changes said to come upon the nucleus during conjugation. But 
to establish his own hypothesis th& whole process of morphological 
change in the nucleus at least should have been followed, and not 
once but many times. Yet the very first complete change effected 
in this organ could not be explained ; and after following it into 
fission as the result of conjugation, he observed four “ nucleolus 
capsules ” as the issue, in each paramaecium. Two of these became 
light and clear ; the other two diminished in size, and became fibrous, 
but on the second day they lost their fibres and became homo- 
geneous and dark ; and on the third day — vanished ! that is to 
say, by the method pursued by the observer, they were lost, and 
‘•no trace of them was to be found.” From this Biitschli con- 
cludes that they were “ cast out,” and no further concern in rela- 
tion to them is evinced ! Yet it must be remembered that Balbiani 
describes a similar condition of the same forms, and considers the 
granules germs or ova. To deal thus lightly with the ejection of 
apparently organized bodies in a set of observations designed to 
prove that what have been considered ovarian, or at least sexual, 
products, was erroneous, is certainly remarkable. Clearly no result 
can be arrived at until the manner of the vanishing of these bodies 
be understood ; and if they were ejected, until their future destiny 
became known. This is all the more imperative from the fact that 
after the ejection of the “ bodies,” the paramaecimn resumes its 
normal condition in size and appearance, although the method by 
which this conclusion is reached is by saltative inferences, and not 
by continuous proofs. 
Again, in B. bursaria and aurelia, two “ light bodies ” — definite 
products of the nucleolus — are repeatedly seen in successive stages 
after conjugation, but having been followed to a certain point we are 
told that “ the further destiny of these two light bodies escaped 
me ” ! and yet it is assumed that the life-history of the creatures 
is known. 
Again, in these same forms the nucleus broke up into a hundred 
spherules ; and yet our author frankly declares, “I am not quite 
certain of the destiny of the . . . fragments of the old nucleus ” ! 
This is the more important since Schaafhausen affirms that he has 
seen P. aurelia lay or deposit ova ; “ the organisms crammed full 
of egg-spheres, surrounded with clear fluid, extrudes in an hour 
several times one such egg.” 
Again, in Colpidium colpoda, after conjugation, two small 
light spheres appear, these the author “ thinks most probably ” 
grow out of the nucleus capsules, while the nucleus itself is cast 
out ; Biitschli followed it “ for some time ” and then it was lost, so 
he does not know its final destiny ! Of what service can all the 
subsequent transformations of the organism itself be when this 
