MATURATION AND FECUNDATION OF THE OVUM. 133 
starts with the process of sexual multiplication in the colonial 
Volvocineae. He does not agree with the theory which regards 
polar globules as the eliminated male element, pointing out that 
in the lower Algae there is no such elimination in the sexual 
conjugation. In this connection I am led to refer to the most 
suggestive remarks on the origin of sexual reproduction in a 
paper by P. Geddes 1 on the cell-theory. Geddes regards the 
original life of a cell as a cycle passing from the encysted 
stage to the ciliated, then to the amoeboid and then to the 
plasmodial. In the last stage the amoebae unite and the union 
results in increased activity of the cells which is shown by 
their greater power of motion and especially in their more rapid 
multiplication. From this plasmodial union, exemplified in 
Myxomvcetes, he derives the sexual union of a male and female 
cell. He points out that a multiple union exists according to 
Gabriel in Actinosphaeria, according to Gruber in Gregarines, 
and results in reproduction. That the nucleus is not indis- 
pensable in conjugation results he thinks from the demonstra- 
tion by Gruber 2 3 that in the young Actinophrys a nucleus is 
really absent and develops independently in adult life; and 
even if the essence of reproduction lies in the union of nuclei 
rather than in that of the protoplasm, we must suppose on the 
evolution theory a primitive stage in which nuclei had not yet 
been developed. All this, however, although giving a common 
me aning to phenomena at first sight isolated, does not explain 
why the nucleus when it does exist plays such a conspicuous 
part in fecundation and exhibits such a universal and striking 
process as the formation of polar globules. We require yet a 
series of patient and skilful researches like these of Van 
Beneden into the phenomena in question in all living forms, 
to give us accurate and more extensive data from which to 
generalise. It is not ten years since Biitschli first discovered 
the directive spindle, and ten years more will probably throw 
1 “ A Restatement of the Cell-theory,” ‘ Proc. Roy. Soc. Edinb.,’ vol. xii, 
1883-4. 
3 * Zool. Anzeiger,’ No. 118, 1882. 
