458 MICRO-ORGANISMS AND DISEASE [chap. 



however, that Pestana's and similar conclusions, notably 

 those arrived at with regard to the non-choleraic origin of the 

 water vibrios previously mentioned, are not to be accepted 

 unconditionally. The observations to which I refer were made 

 on oysters kept in sea-water tanks to which previously culture 

 of the typical cholera vibrio had been added. These vibrios 

 had been originally derived from the flakes of the rice-water 

 contents of a typical fatal case of cholera that had occurred 

 on board of a steamer arriving in the Thames in August 

 1894, from a cholera-infected port; these vibrios had in cul- 

 tivation all the characters of the typical Koch's vibrio, and 

 tested on the guinea-pig's peritoneum showed a considerably 

 high degree of virulence — and, be it also noted, having been 

 carried on in subcultures through many generations showed 

 both the Pfeiffer's test in corpore as also the Bordet-Durham 

 test in vitro with " cholera serum." 



From the slanting surface of an Agar culture — incubated 

 for two days at 37° C. — the growth was scraped off and dis- 

 tributed in sterile salt solution, and then added to the sea 

 water in a tank in which oysters fresh from the oyster-beds 

 had been previously deposited. Several of these oysters as 

 also the sea water had for control been previously carefully 

 examined by the culture test for the presence of vibrios. In 

 the case of the oysters, after well brushing off under a stream 

 of water from the tap the exterior of the shell, the latter was 

 dried with a clean towel, opened with a sterile knife, and of 

 the liquor and the mashed-up substance of the oyster a 

 number of peptone salt cultures were made. Of the sea water 

 90 cc. were placed in a sterile flask, to it were added 10 cc. of a 

 10 per cent, peptone, 5 per cent, salt solution, and the whole 

 was incubated at 37° C. In neither case, the interior of several 

 oysters as also the sea water, were any vibrios discovered. 



After the addition of cholera culture to the sea water in 



