122 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



habitat so experienced would influence the " bacterial flora " 

 characteristic of faeces. Some organisms might be very- 

 resistant, and would maintain themselves, and multiply in 

 sea- water and estuarine shellfish, just as they did in the 

 alimentary canal of man ; while others, being more delicate, 

 that is, more habituated to a truly parasitic mode of life, 

 would speedily die out when they enter a new medium.* 



The organisms which inhabit shellfish must therefore be 

 precisely diagnosed by the application of the fermentation 

 reactions recommended by MacConkey, and their original 

 habitat must be traced. Conversely the organisms inhabiting 

 the human alimentary canal must also be differentiated from 

 each other and diagnosed, and then we must study what is 

 their behaviour in media like fresh water, estuarine sea-water, 

 and the bodies of shellfish. A systematic description of the 

 species of bacteria present in faeces, and an estimate of the 

 relative abundance of the various forms ought to be made, and 

 compared with a similar description and estimate of the 

 species found in shellfish. There will be a difference, and this 

 difference will be due to the change of habitat. The various 

 faecal organisms ought then to be isolated in pure cultures, 

 and their individual behaviour in sea-water and shellfish 

 studied. 



It must be confessed that it is easy to make such a 

 programme of research, but difficult to carry it out. It has, in 

 fact, been little more than suggested in this Report. The work 

 is simply impossible for anyone who has anything else to do. 

 The results here described merely suggest that much more 

 valuable ones might be obtained if a really adequate investiga- 

 tion could be made. 



* See MacConkey, " Further observations on the differentiation of 

 lactose-fermenting bacilli, with special reference to those of intestinal origin," 

 Journal of Hygiene, Vol. IX, No. 1, April, 1909. Clemesha, " The 

 bacteriology of surface waters in the tropics," Calcutta, 1912. 



