886 OYSTERS, AND ALL ABOUT THEM. 



have continued to exist. A thousand mature oysters 

 will produce during a breeding period, ... at least 

 440,000,000 of young ; but upon the beds alongside of 

 these 1000 mature oysters are to be found, on an average, 

 not more than 421 half-grown ones ; so that, as a rule, for 

 every Holstein oyster which is placed upon the table, more 

 than 1,045,000 young are destroyed or die; and indeed 

 even more than this, for not only do those oysters which 

 are over six years of age produce eggs, but those which are 

 two and three years old also reproduce their kind to a cer- 

 tain extent. The younger oysters, however, produce much 

 less spawn than those which are mature, so I estimate that 

 those half-grown oysters lying beside the mature ones, on 

 the same banks, and which are their offspring, will produce 

 60,000,000 young oysters. 



We thus have, upon a surface of oyster-bed occupied 

 by 1000 full-grown and 421 half-grown oysters, at least 

 500,000,000 of young produced during the course of the 

 summer, and of this immense number only 421 arrive at 

 maturity. The immolation of a vast number of young 

 germs is the means by which nature secures to a few germs 

 the certainty of arriving at maturity, In order to render 

 the ideas of germ-fecundity and productiveness more easily 

 understood, I will make a comparison between the oyster 

 and man. 



According to Wappaus, (e) for every 1000 men there 

 are 34-7 births. According to Bockh, ( f) out of every 

 1000 men born 554 arrrive at maturity, that is, live to be 

 twenty years or more of age ; thus, on an average, 34*7 



(e) "Wappaus, Handbuch der Geographic und Statistik. Band I, 

 1855, Abth. I, p. 197. 



(f) Bockh, Sterblichkeitstafel fur den Preussichen Staat im Um- 

 fange von 1865. Jena, 1875. 



