AQUICULTURE 285 



is sewage contamination in the neighbourhood, disease 

 germs such as the bacillus of typhoid. Experiments have 

 shown that the common intestinal colon bacillus is of fre- 

 quent, if not constant, occurrence in the oyster and other 

 shellfish, and that the typhoid bacillus may, though very 

 rarely, be present, and can hve for a short time in the mollusc's 

 interior. These disease organisms can, however, be readily 

 washed out by a stream of running water or by placing for 

 some hours in water which is frequently changed. The 

 living shellfish, in fact, tends by its vital processes to clear 

 itself of such matters, and the t5rphoid bacillus is fortunately 

 a comparatively dehcate organism, and cannot Hve for 

 long in pure sea-water. 



Oyster-culture is pursued in Holland on much the same 

 lines as in France, with somewhat less elaboration, and 

 without the differentiation between the collecting and 

 rearing and the later stages of cultivation seen at Arcachon 

 and Marennes. In a Dutch oyster-farm, as at lerseke or 

 at Bergen-op-zoom, or elsewhere on the Scheldt, we may 

 see spat collection by means of tiles, and also the distribution 

 of cockle-shells to form a " cultch," the rearing of young 

 oysters in ambulances, their further cultivation in the later 

 years of their life in ponds, which can be filled and emptied 

 from canals with sluices ; and in some cases young oysters 

 shipped from Arcachon are relaid and fattened in Holland, 

 and even on some parts of the EngUsh coast, in place of 

 going to the "claires" of Marennes and Brittany. 



Oyster-culture in the Mediterranean, where there is little 

 or no tide, is carried on in the Bay of Spezia and elsewhere 

 by means of poles stuck in the sea-bottom in shallow water 

 connected by a network of coarse twisted ropes, in the 

 interstices of which the oysters are attached so that they 

 hang in great vertical strings in the water. This is merely 

 a device for accumulating as large a number of oysters as 

 possible in a given area of water, and also to render them 

 easily accessible, so that a man going round the poles in a 



