PUTEEFACTION AND INFECTION. 83 



particles, and that in forty-eight hours subsequently buds 

 and blades of well-defined cresses and grasses appear 

 above the soil. Suppose the experiment when repeated 

 a hundred times to yield the same unvarying result. 

 "What would be our conclusion ? Should we regard 

 those living plants as the product either of dead dust, 

 or of mineral particles ? or should we regard them as 

 the offspring of living seeds ? The reply is unavoidable. 

 We should undoubtedly consider the experiment with the 

 flower-pot as clearing up our pre-existing ignorance; 

 we should regard the fact of their producing cresses and 

 grasses as proof positive that the particles sown in the 

 earth of the pot were the seeds of the plants which have 

 grown from them. It would be simply monstrous to 

 conclude that they had been ' spontaneously generated.' 



This reasoning applies word for word to the develop- 

 ment of Bacteria from that floating matter which the 

 electric beam reveals in the air, and in the absence of 

 which no Bacterial life has been generated. I cannot 

 see a flaw in the reasoning ; and it is so simple as to 

 render it unlikely that the notion of Bacterial life being 

 developed from dead dust can ever gain currency among 

 the members of the medical profession. 



It has been said of those whom the evidence adduced 

 in favour of spontaneous generation fails to convince, 

 that they seem willing to believe in almost any infringe- 

 ment of natural uniformity rather than admit the 

 doctrine.' This surely is an inversion of the true order 

 of the facts. Natural uniformity is the record of expe- 

 rience ; and, apart from the phenomena to be accounted 

 for, there is not a vestige of experience, possessed either 

 by the man of science or the human race, which warrants 

 the notion that dead dust, and not living seed, is the 

 source of the crops which spring from our infusions 

 ' Transactions of the Pathological Society, vol. xxvi. p. 273. 



