47 



infection with typhoid fever through eating raw mussels, 

 and particularly raw cockles, is an occurrence of which 

 several instances are on record. I would refer amongst 

 others to the reports of Dr. Nash, Dr. Thresh, and Dr. Allen. 

 It is, therefore, important to see in what way the cockle 

 and mussel are capable of dealing with the B. typhosus 

 which happen to have access to them. 



EXPERIMENT V. 



A batch of fine cockles was received direct from Leigh- 

 on-Sea; they arrived in sand. After well rinsing several 

 dozen of the cockles on the outside they were transferred to a 

 clean tub, and 2000 c.c. of sea water infected with B. typhosus 

 to the amount of four millions per 1 c.c. were poured over 

 them ; in this infected sea water they were left for 24 hours. 

 They were then taken out, well rinsed on the outside with 

 clean sea water, and two cockles being retained for immediate 

 analysis, the rest were placed in clean sand wetted with 

 sterile sea water. This procedure, namely, rinsing them with 

 clean sea water and then keeping them in clean sand wetted 

 with a little sterile sea water, was found to be the safest way 

 of keeping them alive. Keeping them in sea water alone 

 which was tried with a portion of the infected cockles 

 failed, because they soon died; but keeping them in wet 

 sand succeeded, as it is the nearest approach to the way in 

 which cockles naturally live. 



The fresh sand wetted with sterile sea water was again 

 changed after two, four, six, nine, and eleven days. As stated 

 just now, two of the cockles (1 and la) were analysed after 

 having been 24 hours in the typhoid infected sea water. In 

 this, as also in all the subsequent analyses, both of cockles and 

 mussels, exactly the same methods were followed as have 

 been described in the experiments with the oysters, and it 

 is not necessary to repeat the details of the entire procedure 

 again, except to state that after opening the cockles or 

 mussels the liquor within the shell was drained off as much 



