458 THE POPULAR SCIENCE MONTHLY. 



enee of these, and the development of bacteria is inevitable. The in- 

 ference is that the motes are germs. The above experiments show 

 that, in closely allied septic organisms, the germs of which have been 

 demonstrated and their developments watched, if the dry debris of a 

 maceration in which these forms are found be scattered in the air 

 around a prepared fluid, and demonstrated by similar optical means, 

 the said organisms develop; but if the minute dust from the debris 

 be optically proved to be absent, none of the monad -forms ap- 

 pear. Here we do not hypothecate a germ, but we know that it 

 exists ; and its deportment in similar conditions is identical with that 

 of the assumed bacterial germ. Do we need more irresistible evi- 

 dence that the bacteria develop, not de novo, but from genetic prod- 

 ucts ? 



Evidently Dr. Bastian thinks we do. He tells us in effect that, if 

 Dr. Tyndall has not succeeded, others have, in seeing bacteria reap- 

 pear in infusions that have been exposed to a boiling-heat for five 

 minutes. This is true ; but not to the extent nor with the meaning 

 Dr. Bastian claims. He furnishes a list in Nature, 1 for example, of 

 those who are supposed to have secured the results he insists on. 

 But this list is, perhaps hastily, but in effect, most unjustly framed. 

 It is not surprising to see strong protests from the investigators con- 

 cerned. 2 The citing of Roberts, for example, or Lankester and Pode, 

 or Pasteur or Schwann, is simply a meaningless exercitation to all but 

 the ignorant. Stripped of all disguise, the number of cases of the 

 appearance of bacteria in sealed infusion after five or ten minutes' 

 boiling is few and doubtful indeed. But still there are cases, and in 

 one instance at least admirably attested ; but they are confessedly 

 exceptional in a high degree. Dr. Bastian, however, prefers to inter- 

 pret Nature from the exceptional flasks, and infer " spontaneous gen- 

 eration" rather than be guided by the cumulative and overwhelming 

 evidence of the existence of bacterial germs, as the medium of their 

 normal reproduction. This must mean either that he believes that 

 these organisms originate de novo as well as by germs, which is a 

 direct petitio principii / or else that he is incapable of seeing the 

 force of the facts which render the existence of germs inevitable. 

 From the conflicting evidence of his own writing it would almost 

 appear that he endeavored to maintain both these views. He has 

 recently said, "Prof. TyndalPs results, admirable as they may be in 

 themselves, are altogether collateral, and do not bear upon the main 

 point at issued 3 Surely the " main point at issue " is the mode of 

 origin of bacteria, and w r e cannot get much nearer the origin of an 

 organic form than by tracing it to a genetic product a spore ! This 

 was originally Dr. Bastian's question did bacteria originate de novo, 

 or from parents ? It is not so now. He says, " The question is, not 



1 February 10, 1876. 2 E. G., Nature, February 24, 1876, p. 324. 



3 Times, January 29, 1876. 



