(39) 



XII.— CONDITION OF OYSTER BEDS AND LAYINGS. 



It has been known for some time that many of the places in estuaries or 

 harbours where oysters are laid down to fatten, or to await their market, have been kept 

 in a most insanitary condition, either because the water as a whole is polluted, or 

 because the opening of some drain-pipe is in such close proximity that the discharge 

 from the drain is liable to pass over the shellfish. We showed in 1895, in our 

 preliminary paper, that oysters have a very remarkable power of withstanding organic 

 impurities in the water, and can continue to live in water much polluted with sewage. 

 In fact they are able, if kept sufficiently aerated, to render water almost opaque with 

 sewage clear in a wonderfully short time. 



As the result of our observations on oyster-beds, and our experiments on the 

 kinds of water in which oysters will live, we recommended, in January, 1896,* 



" 1st, A strict examination of all grounds upon which oysters are grown or 

 bedded so as to ensure their freedom from sewage ; and 

 2nd, If practicable, the use of ' degorgeoirs ' or disgorging tanks, in which the 

 oysters should be placed for a short time before they are sent to the 

 consumer." 



Towards the end of the same year, the Local Government Board Report on 

 Oyster culture in relation to Disease, containing sections by Sir Richard T. Thorne, Dr. 

 H. T. Bulstrode, and Professor E. Klein, appeared, giving detailed statements as to the 

 insanitary conditions under which oysters are grown or kept on various parts of our 

 coasts. Dr. Bulstrode has shown conclusively, by his descriptions and plans, what was 

 known previously only to those who had taken the trouble to look into the matter, 

 that while some of the localities from which our oysters come to market are excellently 

 suited for the purpose and free from reproach, other " layings " are in a disgraceful 

 condition of sewage contamination. That is undoubted ; but as to the further question, 

 whether the typhoid organism, if it gains access to the body of the oyster from sewage, 

 finds itself in a suitable medium for continued life and multiplication, it is difficult 

 to arrive at any definite conclusion. Professor Klein's experiments, like our own (see 

 below, p. 45), are not sufficiently extended to be positive upon this point. There is, however, 

 a marked difference between the cultures obtained from oysters taken from a contaminated 

 source and those from pure water free from all possible sewage pollution. The body 

 of the oyster is probably not a favourable medium for the growth of pathogenic organisms, 

 the risk of infection is probably therefore never great, and if a little more care were 

 exercised there would be practically no danger at all. 



* Report to the Lancashire Sea Fisheries Committee: Trans. Biol. Soc. Liverpool. Vol. X., p. 174. 



