BACTERIA AND THEIR ALLIES 171 



effect an entry into a single vegetable cell, and then let him imagine 

 what an army of Bacteria would be needful, with all the cytase 

 they could excrete, to get through such a tough and thick layer as 

 that presented by the fibrous capsule of the kidney. But surely the 

 whole notion as to such a mode of infection of the kidney and 

 other abdominal organs is too absurd for serious consideration. 



We are, then, driven back to inquire whether it is true that the 

 blood is germless, and whether it has, in reality, the bactericidal 

 qualities with which it is credited. I have no evidence whatever 

 to oppose to these beliefs ; nor is it easy to see, even if bacteri- 

 ologists generally should be wrong in their views as to these 

 points, how it would suffice to explain the development of 

 Bacteria within all the cells of a kidney treated in the way I 

 have mentioned. 



It is perfectly certain that the blood of healthy persons does not 

 contain any appreciable number of active Bacteria. But are 

 bacteriologists right in supposing that such Bacteria as get into the 

 blood stream are " destroyed " ? May they not rather be reduced 

 to a condition of latent vitality ? Their answer to this is, that if it 

 were true, the organisms would be capable of revealing their 

 presence when suitable media were inoculated with them and 

 subsequently exposed to proper incubating temperatures. And it 

 is the negative results of all such experiments with the blood of 

 healthy animals that confirm them in their belief as to the germi- 

 cidal qualities of the blood. 



Nor, in fact, if the blood were assumed to be full of latent germs 

 of Bacteria would it be easy, as I have intimated, to see how that 

 would enable us to explain the development of Bacteria within 

 almost every epithelial cell in the kidney referred to. Could 

 organisms reduced to a condition of " latent vitality " penetrate 

 the walls of the capillaries, and thence migrate into all the cells of 

 a kidney tubule ? The notion is again too preposterous to be 

 entertained ; so that we are compelled, by evidence of a most 

 convincing character, to admit that the Bacteria have in reality 

 been born in the individual cells of the kidney — ^we are compelled 

 to believe that heterogenesis has, in fact, been taking place here, as 

 in the other instance previously cited. 



We may turn now to see what evidence is forthcoming con- 

 cerning the heterogenetic origin of Bacteria and their allies within 

 the tissues of plants and other vegetal organisms. 



