In the beginning...animal fertilization and sea urchin development.
What I most wished to discover [in my study] was the role that spermatozoids play in fertilization. In order to determine this, I put a droplet of red liquid, and at a small distance, a similar droplet of white liquid in a little trough on the viewing slide of the microscope; then, after covering all of this with a thin strip of glass, I added a drop of sea water. I was then able to watch the spermatozoids advance progressively towards the eggs. Some of [the eggs] were soon encircled by a compact mass of moving corpuscles; others, farther away, only found themselves in contact with a very small number [of sperm]; in both cases, I saw the signs of fertilization. The first apparent effect of this union is the almost immediate appearance of a perfectly transparent envelope that encircles the yolk at a certain distance, which is manifested by the appearance of a circular line. I saw this envelope manifest when in contact with a very small number of spermatozoids (three or four, sometimes even one only).
Briggs
Elissa
E
Department of Molecular Biology, Cell Biology and Biochemistry, Box G, 69 Brown Street, Brown University, Providence, RI 02912, USA.
Wessel
Gary M
GM
D000818:Animals; D004625:Embryo, Nonmammalian / Q000502:physiology; D005260:Female; D005306:Fertilization; D005854:Germ Cells / Q000502:physiology; D008297:Male; D012617:Sea Urchins / Q000196:embryology / Q000254:growth & development*