212 ORIGIN AND NATURE OF LIFE 



strength, is placed under a microscope, 

 the organisms are to be seen propelling 

 themselves about actively in all directions, 

 and fairly uniformly distributed. The same 

 effect is seen if the enteric culture be mixed 

 with a small amount of the fluid part of the 

 blood of a normal person (diluted normal 

 serum). But if the serum of a person suffering 

 from enteric fever be taken, a minute drop 

 being all that is necessary, and equally 

 diluted, then on mixing this with the enteric 

 culture as before, and examining under 

 the microscope a most remarkable result is 

 seen. All the enteric organisms, which before 

 were swimming about freely, in about ten 

 to fifteen minutes are found to have gathered 

 themselves together, into clumps of half-a- 

 dozen to a score, or, as it is termed, have 

 agglutinated. The flagellae are still moving 

 but only to preserve the clumped arrange- 

 ments. If bacteria possessed minds it would 

 almost seem as if the situation were being 

 debated at meetings, much as war news 

 might be discussed in a distracted com- 

 munity. The chemical basis of the pheno- 

 menon is that in the blood of the patient 

 afflicted with the enteric fever, minute traces 

 of an anti-body to the enteric organism have 

 been produced in an amount far too slight 



