THE ORIGIN OF LIFE 159 



cell by the union (or, we might say, reunion) of two 

 daughter-nuclei derived from the same mother-nucleus. Au- 

 togamy occurs not only among the protists {e.g. Amoeba 

 albida), but also among the metists, as is the case with the 

 brine shrimp, Artemia salina, in which the diploid number 

 of chromosomes is restored after reduction by a reunion of 

 the nucleus of the second polar body with the reduced nu- 

 cleus of the egg. Autogamy is somewhat akin to kleistogamy, 

 which occurs among hermaphroditic metists of both the plant 

 and animal kingdoms. The violet is a well-known example. 

 In kleistogamy or self-fertilization, the zygote is formed 

 by the union of two gametes derived from the same parent 

 organism. Strictly speaking, however, kleistogamy is not 

 autogamy, but syngamy, and must, therefore, be classed as 

 bisexual reproduction. It is, of course, necessarily confined 

 to hermaphrodites. 



Loeb's experiments in artificial parthenogenesis have been 

 sensationally misinterpreted by some as an artificial produc- 

 tion of life. What Jacques Loeb really did was to initiate devel- 

 opment in an unfertilized egg by the use of chemical and phys- 

 ical excitants. The writer has repeated these experiments with 

 the unfertilized eggs of the common sea urchin, Arbacia punc- 

 tulata, using very dilute butyric acid and hypertonic sea 

 water as stimulants. Cleavage had started within an hour 

 and a half after the completion of the aforesaid treatment, 

 and the eggs were in the gastrula stage by the following morn- 

 ing (9 hours later). In three days, good specimens of the 

 larval stage known as the pluteus could be found swimming 

 in the normal sea water to which the eggs had been trans- 

 ferred from the hypertonic solution. Since mature sea urchin 

 eggs undergo reduction before insemination takes place, the 

 larval sea urchins arising from these artificially activated 

 eggs had the reduced or haploid number of chromosomes in- 

 stead of the diploid number possessed by normal larvae arising 

 from eggs activated by the sperm. For, in fertilization, the 

 sperm not only activates the egg, but is also the means of secur- 



