XIX 
THE FERTILIZING EFFECT OF SPERM EXTRACT 
1. In 1899 Piéri published a note to the effect that by merely 
shaking up the testes of the sea-urchin in sea-water he had 
been able to extract a substance which fertilized the egg of the 
sea-urchin.! The sea-water containing the spermatozoa was 
filtered after the shaking, and the filtrate added to the eggs. 
The eggs developed. As the author himself states, and as is 
generally known, spermatozoa pass through filter paper, and 
so one cannot quite understand on what the author bases his 
statement that we are concerned here with a fertilization by 
sperm extract, and not by living spermatozoa; control experi- 
ments were not performed. A better addition to the solution 
of the problem was made by Winkler.? He states that his 
work has not gone beyond a preliminary stage. His experi- 
ments consisted in putting the spermatozoa of two kinds of 
Naples sea-urchins, Sphaerechinus and Arbacia, into distilled 
water for half an hour. The filtrate was able to produce the 
first segmentation stages in the sea-urchin. It will be seen, 
however, that Winkler did not work with unaltered sea-water, 
and it is possible that the alteration of the sea-water and not 
the hypothetical substances extracted from the sperm was the 
cause of the segmentation that he observed. 
If the spermatozoa were simply killed by being heated in sea- 
water to between 50° and 60°C., and the eggs put in this liquid, 
nothing happened. But if they were put into distilled water for half 
17. B. Piéri, ‘‘ Un nouveau ferment soluble: L’ovulase,"’ Arch. de Zool. expér. 
et gén., XXIX, 1899. 
2H. Winkler, ‘‘ Ueber die Furchung unbefruchteter Eier unter der Einwirkung 
von Extractivstoffen aus dem Sperma,’’ Nachrichten der Ges. d. Wissensch. zu 
Géttingen, 1900, 187. 
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