472 THE BEGINNINGS OF LIFE. 



He says l : t If, on the one hand, it is urged that all 

 organisms, in so far as the early history of them is 

 known, are derived from ova, and therefore from 

 analogy, we must ascribe a similar origin to these 

 minute beings whose early history we do not know; 

 it may be urged with equal force, on the other hand, 

 that all ova and spores, in so far as we know anything 

 about them, are destroyed by prolonged boiling : there- 

 fore from analogy we are equally bound to infer that 

 Vibrios, Bacteriums, &c., could not have been derived 

 from ova, since these would all have been destroyed by 

 the conditions to which they have been subjected. 

 The argument from analogy is as strong in the one 

 case as in the other. 3 



We do not think, however, that the analogical 

 arguments are so nearly balanced as Prof. Wyman 

 appears to consider them. Whilst it would contradict 

 all our previous experience, and violate the uniformity 

 of natural laws, if certain pre-existing germs had been 

 able to survive the exposure to which they must have 

 been subjected in my experimental flasks, it would in 

 no way outrage our experience if we found that specks 

 of living matter might form de novo in some fluids, just 

 as specks of crystalline matter form in other fluids 

 especially as they do actually appear, under the micro- 

 scope, to arise in this way. The physical doctrines of 

 life which are now so widely believed in, speak unhesi- 



1 ' American Journal of Science and Art,' July, 1862. 



