LIVING SPIROCHAETES 19 



pipette and injures the mollusc. On many occasions I hâve 

 found Spirochaetes swimming freely in the hquid in the mantle 

 cavities of oysters and Anodons, and also at différent levels 

 in the water in which thèse molluscs were kept. This occurrence 

 of Spirochaetes in the water surrounding the molluscs, in their 

 mantle cavities and in their mouths conclusively confirms the 

 statement of Fantham that the mode of infection is casual, 

 namely, by the mouth. 



Examination of organs of the Anodon and oyster, other than 

 those of the digestive tract, yielded Httle resuit. The heart, 

 gills, liver and organ of Bojanus were carefully searched, but 

 with négative results. Many Glochidia were examined and also 

 reproductive tissues, but with one exception no Spirochaetes 

 were found. Once, however, a fresh préparation of Glochidia 

 showed a solitary Spirochaete, so that possibly Anodons 

 become infected early in hfe. No « cysts » were ever found in 

 the faeces of the molluscs. 



VII. — Some effects of environmeiit on Spirochaetes. 



There is no doubt that Spirochaetes are affected by their 

 environment to some extent, but they are often not noticea- 

 bly sensitive to environmental change, possibly owing to the 

 thickness of their periplast. The behaviour of S. baîbianii and 

 S. anodontae under différent conditions of température and 

 pressure, and in cultures, has been very fuUy investigated by 

 Fantham (1908) who also performed a séries of chemical reac- 

 tions to détermine the nature of the periplast of thèse organisms. 

 In connection with environmental effects I hâve noticed the 

 folio wing in the course of my investigations. 



Effect of change of TEMPERATURE. I put portions 

 of infected styles, containing 8. baîbianii or S. anodontae, in 

 sea-or fresh-water respectively, and then placed the préparation 

 in a thermostat kept at about 20^ 0. Though this température 



