BACTERIA NOT PROVED. 263 



that creature must also be killed by the same agency. 

 To this it is replied that, 1st, Owing to various cir- 

 cumstances, especially the presence of solid particles 

 in the solutions, the heat really did not penetrate to 

 all the individuals in the time during which it was 

 applied ; and 2nd, It was shown by the observations 

 and experiments of Mr. Dallinger and myself* that, in 

 the case of several mona,ds found in putrefying solu- 

 tion having the same title to be called spontaneous 

 products as bacteria, besides their mode of multiplica- 

 tion by fission, they were propagated by extremely 

 minute germs, which were seen to grow to the adult 

 form after exposure of the slide to a heat which was 

 fatal to any adult living creature. I hold, therefore, 

 that, although the question is not yet fully settled, the 

 adherents of spontaneous generation of putrefactive 

 infusoria have entirely failed to establish their posi- 

 tion. 



Nevertheless, I admit that the recent investigations 

 of the subject, especially by Dr. Bastian, in his " Be- 

 ginnings of Life," are worthy of all praise, and it is 

 consistent with sound philosophy that the question 

 should be submitted to experiment. It was not a 

 matter to be cried down, as some have wished to do, 

 but it is a subject in which repeated experiment was 

 necessary, and is still necessary. 



Nor do I agree with those who condemn the whole 

 object of the investigation as impious. Those who 

 suggest that it is so should remember that Needham, 

 who revived the doctrine in the last century, was a 

 Catholic priest, and was, nevertheless, free from any 

 * "M. Microscop. J.," 1873-4.J 



