292 BACTERIA GERMS IN THE BODY. 



more probable that the germs were derived from some 

 which existed in a passive dormant state in the tissue 

 itself (see page 66). Such an origin appears never to 

 have suggested itself to Prof. Lister, and he remarks, 

 as if it were an argument in favour of his doctrine, 

 that if we do not admit that the germs were intro- 

 duced from without, there is nothing left for us but to 

 accept the ridiculous notion that bacteria were formed 

 spontaneously out of the pus. Bacteria can no more 

 be produced by pus than they can by epithelium. Pus 

 can have no more to do with the origin of bacteria 

 than the latter with the origin of pus. Pus may live 

 without bacteria and bacteria without pus. If we 

 assume that the only way in which bacteria can get 

 into the substance of the tissues is directly from the 

 outer air, we shall find it impossible to explain some 

 of the facts adverted to on p. 69, and new difficulties 

 would arise in connection with other phenomena, 

 which are to be fully accounted for if, as I believe is 

 the fact, living bacteria germs exist dormant in the 

 tissues even in the healthy state, but do not grow and 

 multiply unless certain changes take place in the 

 organic matters around them. 



And it seems equally unreasonable to infer that 

 when bacteria are found in the blood, the germs ob- 

 tained access to that fluid from without shortly before 

 they were discovered. Bacteria are developed upon the 

 surfaces of calculi in the urinary organs, and probably 

 exist in some parts of the living fcetus while yet in 



