By taking unfecundated eggs and placing them for two minutes in a mixture of sea water and acetic, or butyric, or valerianic acid, then placing them back in sea water and twenty minutes later, immersing them for about an hour in hypertonic sea water or sugar solution, and finally returning them to sea water, Loeb was able to bring to life young larvæ. A French scientist, Delage, repeating the same experiments managed to keep those larvæ alive until the time of their sexual maturity.
Loeb also succeeded in fertilising eggs by placing them in the blood serum of cows, sheep, pigs or rabbits.
Mathews has fertilised some by shaking them gently for a period of time.
Twins To Order. Loeb and others have gone further even than that and produced not only single individuals but twins, triplets, etc.
The secrets of nature's laboratory are being revealed more and more clearly from day to day.
The conceited fathers who imagine that the bringing into life of twins is a symptom of their powerful virility must learn that a mere chemical phenomenon called osmosis is responsible for the over-fertility of some wives.
Remove from sea water sea urchin's eggs and place them for fifteen minutes or so in ordinary water. The density of water being lower than that of sea water, the eggs will absorb a great deal of water and burst open. A drop of protoplasm will come out at the break in the membrane. Replace the exploded egg into sea water and two larvæ will hatch out of it. Separate the two portions of the exploded egg and the twins will be as healthy as tho they had been allowed to grow for a while in Siamese style.
By repeating the experiment, Loeb has produced not only twins but triplets and quadruplets, all normal and growing out of the same egg which was only meant originally to produce one urchin.
One can understand how a variation in the pressure of the liquids surrounding the human egg may lead to the same result.