OYSTER CULTURE. 283 



been successful in getting much, tlie amount being quite insigni- 

 ficant to tlie labour and expense of putting tbem down. 



There are plenty of shells and natural stuff for oysters to settle 

 on in the river if ever a fall of spat matures. That some do mature 

 every year I have no doubt, but the quantity is very small. 



I do not know that new natural spat in the river is stronger than 

 that collected in the ponds. The shallowness of the water in the ponds 

 causes the water to be warmer in summer, and this stimulates a 

 greater growth in the young oysters in the ponds, but exposes them 

 to greater risk from cold or snow water in the winter. 



That oysters sicken and give a fall of spat every year I do not 

 doubt, but it has always been a difficulty to ascertain if that spat is 

 mature.* There has been a fall of spat every year in the ponds 

 more or less, but it has most yeai's come to nothing. After floating 

 about for a week it will disappear altogether. I should like to 

 know the cause of this, and here is where some scientific research 

 is greatly needed. The problem is, why does this spat disappear ? 

 I have not been able to account for it from any natural causes. I have 

 had large bottles of spat and watched it through powerful magni- 

 fying glasses and under a microscope, and have never been able to 

 see any other living organism preying upon it. The spat has been 

 very lively and moving about, apparently full of life, and, as far as I 

 could see, having no marked difference from spat which has matured 

 and adhered properly to collectors. Why does it not do so ?t I have 

 tried every kind of oyster in the ponds, putting about 10,000 in each 

 pond. French oysters from Arcachon, French oysters from Auray, 

 Solent oysters, river oysters, Falmouth oysters. The former breed 

 much the most prolifically ; and my belief is that this is owing to 

 their being matured in a warmer climate. If, therefore, there 

 happens to be a fine week when they emit their spat, the chances of 

 realising a good result are greater with them than other oysters. I 

 have usually placed the oysters I intended to breed from in shallow 

 ponds by the sea-shore ; this has the effect of bringing them on, and 

 causing them to mature their spat. I believe that climate and 

 warm weather has more to do with success than anything else, and 

 the maturity of the spat when it is emitted from the oyster depends 

 greatly on this also. 



It is also most essential that the surface for oysters to spat upon 



* The fall of spat has varied greatlj' in date : sometimes in June, often not till the end 

 of July. I have hardly ever known a late spat come to maturity. 



t I have generally put the mother oysters into the ponds about the end of May or 

 beginning of June. The oysters I have selected have been generally about three years old. 

 It is a question perhaps whether the spat from older oysters do not mature better. Those 

 I have had from France have been between three and four years old. 



