PROFITABLE CULTIVATION OF THE OYSTER. 877 



for if this mitnber of oysters is spread over a space 30 German miles 

 square, there would be 1,332 to every square meter.* 



If, iu spite of this, the oyster-beds have uot extended over the whole 

 ^^Watten Sea,''^ the reason cannot be that the quality of the water is 

 less favorable to the oyster in some places than in others; for throughout 

 this whole sea it has the same quantity of salt, viz, 3 to 3.2 per cent. The 

 temperature is likewise the same everywhere, for both in the oyster-beds 

 and in other places it varies in the course of the year 20^ above to 2° 

 below zero (Celsius). Want of food cannot be the cause why the oyster- 

 beds have for centuries kept within certain limits, for the water of this 

 sea is full of microscopic plants and animals and decaying organic mat- 

 ter, all of which might serve as food for the oysters. The only remain- 

 ing natural cause which could hinder the oyster-beds from extending and 

 increasing is the unfavorable character of the bottom in the greater por- 

 tion of the " Wattcn Sea.''^ Oysters do not flourish on hottom consisting of 

 quicJx'sand or deposits of clayey mud mixed with organic matter. And one 

 of the two is found in the greater portion of the bottom of the " Watten 

 SeaJ^ The size and number of those places where, iu spite of the tide, 

 the bottom remains firm and free from deposits, is very limited, and only 

 in these limited spaces oyster-beds can be formed. In order to explain 

 this I must say a few words on the structure and development of the 

 oyster. 



The mother-oyster does not lay her eggs immediately in the water, 

 but keeps them in the so-called beard (the gills of the oyster) until the 

 little creatures are able to swim. These young oysters, of a bluish color 

 and 0.15 to 0.18™™ long, swarm about in the water and finally settle on 

 the bottom. 



If this young oyster gets to a place where there are clean stones or 

 shells on which it can grow, there is a prospect of its reaching its full 

 size, but if it gets on quicksands or muddy deposits, it is lost ; for, as it 

 has no feet, like some other shell-fish, it cannot work itself out of the 

 sand and clay. 



Most of these young oysters doubtless die very soon, because they find 

 no clean places on which to grow. This circumstance has led to the 

 artificial cultivation of the oyster in France, whose author is Professor 

 Coste, of Paris. In the spring of 1858 he distributed in the bay of St. 

 Brieux shells and heavy fagots over a space of 1,000 hectares (1 hectare 

 = 2.4711 acres), and on these spread 3,000,000 mother-oysters. In 

 autumn all the fagots were of course covered with young oysters ; for, 

 if these oysters were as fruitful as the Holstein oysters, there were 

 132,000 young oysters to every square meter. The boldest expectations 

 were exceeded. It was thought that now the means had been found to 

 surround every French coast with oyster-beds, and people already com- 



* Iu a work on "The Oyster and its Cultivation," which I intend to xiublish very- 

 soon, I shall give the data on which these figures are based. I feel convinced that 

 they are not exaggerated, but are rather below the actual figures. 



