STERILIZATION 



171 



sewage-polluted shell-fish, and afterwards proved that the per- 

 centage of cases due to this cause was in 1894, 1895, 1896, and 

 1897, 38*2, 33*9, 31*8, and 307 respectively/ and that at least 

 one-third of these cases are due to mussels/^ Dr. Nash in 1900 

 obtained clear evidence that a severe outbreak of typhoid fever 

 at Southend was originated by infected cockles.^ These had 

 been obtained from a sewage-polluted creek in another district ; 

 had been scraped up with an ample amount of mud attached, 

 then washed on a sieve in the creek water, and partially cooked 

 by being plunged into an open copper containing very hot 

 water. In a few minutes, when the shells opened, the cockles 

 were removed, the shells separated by sifting, and the fish either 

 Isold at once or pickled in brine for transport. 



The important points are that the usual cleansing is delusive, 

 and the parboiling commonly practised is no protection. 

 Dr. Thresh, in an experiment with these cockles, washed them 

 ^twice with pure water, and then plunged them into boiling 

 water. At the end, living sewage bacteria were present in the 

 liquid draining from them, a result confirmatory of conclusions 

 previously arrived at by Dr. Klein, working with oysters, 

 |cockles, and mussels, and with typhoid and cholera organisms, 

 who, moreover, found that the organisms remained even when 

 the infected water had been replaced for three days by clean 

 ■ sea water, and that they actually increased in numbers within 

 |the bodies of the shell-fish.* Dr. Nash also remarks^ that 

 inquiries should not be limited to the eating of shell-fish, but 

 should extend to the handling of such from suspicious sources, 

 since germs can easily be carried from the hands to the mouth. 



The proofs of the connection between polluted shell-fish and 

 typhoid are clear and numerous, and have been summed up by 

 Newsholme,^ and also in the Fourth Report of the Royal Com- 

 mission on Sewage, vol. i., p. xv. In the careful surveys of the 

 gathering-grounds of England and Wales in 1894 and 1895, 

 and of Ireland in 1903, conducted for the Local Government 

 Board, it became evident that a number of them were liable to 

 invasion by recent sewage. Its discharge into tidal waters 

 came into wide public notice in 1903, in connection with serious 



^ Journal of the Royal Sanitary Institute^ vol. xvii., part iv., January, 1897. 



- Ibid., vol. XXV., part iii., October, 1904. 



^ Ibid.y vol. xxiii., part iv., January, 1903. 



"* Report of Medical Officer to Local Government Board, 1900-1901, p. 567. 



^ Public Health, August, 1902. 



^ Journal of the Royal Sanitary Institute, October, 1904, p. 454. 



